Steven H. Strauss

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Name: Strauss, Steven

Organization: Colorado State University , USA

Department: Department of Chemistry

Title: Professor(PhD)

TOPICS

Inorganic Chemistry

Organic Chemistry

Chemicals
References

X-ray structures and electronic properties of the 1,1′,2,2′- and 1,1′,3,3′-tetra-t-butylferrocenium(1+) cations

Co-reporter:Kristina M. Gansle, Alexander E. Gash, C. Kevin Chambliss, Brady J. Clapsaddle, Brian S. Newell, Susie M. Miller, Oren P. Anderson, Russell P. Hughes, Steven H. Strauss

Polyhedron 2017 Volume 121() pp:88-94

Publication Date(Web):10 January 2017

DOI:10.1016/j.poly.2016.09.027

The compounds 1,1′,2,2′- and 1,1′,3,3′-tetra-t-butylferrocene (1,2-BUT and 1,3-BUT, respectively) were oxidized with AgReO4 in dichloromethane and the ferrocenium(1+) salts were isolated, after recrystallization from acetone, as dark-blue or dark-green crystals of [1,2-BUT+][ReO4−] and [1,3-BUT+][ReO4−]·acetone, respectively, which were suitable for X-ray diffraction. As expected from the known structures of the neutral ferrocenes, the di-t-butylcyclopentadienyl (Cp′) rings are virtually parallel in the 1,2-BUT+ cation and are tilted by 11.6° in the 1,3-BUT+ cation. The FeC distances in both cations span a greater range and are, on average, longer than in the corresponding neutral ferrocenes. UV–Vis spectra revealed that λmax for yellow 1,2-BUT (442 nm) is lower than for orange 1,3-BUT (466 nm) and that λmax for blue 1,2-BUT+ (674 nm) is lower than for green 1,3-BUT+ (682 nm). In addition, E1/2(+/0) values determined by cyclic voltammetry in dichloromethane, reported here for the first time, show that 1,3-BUT (−0.24 V versus Fe(Cp)2+/0) is 50 mV easier to oxidize than 1,2-BUT (−0.19 V versus Fe(Cp)2+/0). A comparison of the structure of [1,2-BUT+][ReO4−] with that of the literature compound [1,3-DEC+][ReO4−] shows that the shortest Fe⋯Re distances in the two salts are ca. 5.8 Å, indicating that the effective ion-pairing radii of the two cations are essentially the same in spite of the much greater overall size of the 1,3-DEC+ cation (1,3-DEC+ = 1,1′,3,3′-tetra(2-methyl-2-nonyl)ferrocenium(1+)). This surprising result is significant as far as differences in anion-extraction equilibria reported previously.The effects of t-butyl group positions on structure and E1/2 and λmax values of 1,1′,2,2′- and 1,1′,3,3′-tetra-t-butylferrocenium(1+) cations are reported. Minimum Fe⋯Re distances show that their effective ion-pairing radius is not smaller than that of the 1,1′,3,3′-tetra-(2-methyl-2-nonyl)ferrocenium(1+) cation, a result that bears on anion-extraction equilibria reported previously.

Efficient direct fluorination of the B12H11(NH3)− anion in acetonitrile and comparison of the structures of Na(H2O)4(B12F11(NH3)), Na(H3O)(H2O)3(B12F12), and Na2(H2O)4(B12F12)

Co-reporter:Eric V. Bukovsky, Amanda M. Pluntze, Steven H. Strauss

Journal of Fluorine Chemistry 2017 Volume 203(Volume 203) pp:

Publication Date(Web):1 November 2017

DOI:10.1016/j.jfluchem.2017.06.006

•Direct per-B-fluorination of K(B12H11(NH3)) in acetonitrile is more efficient than in liquid anhydrous HF.•The yield of recrystallized K(B12F11(NH3)) is 70% based on K(B12H11(NH3)).•The addition of solid KF to the reaction mixture results in decomposition of B12H11-nFn(NH3)− anions as n approaches 11.•The buildup of HF does not slow down the direct fluorination of either B12H11(NH3)− or B12H122− in anhydrous acetonitrile.•The structures of Na(H2O)4(B12F11(NH3)) and Na(H3O)(H2O)3(B12F12) were determined by X-ray crystallography.An efficient procedure for the direct per-B-fluorination of the potassium salt of the mono-ammonioborane anion B12H11(NH3)− in anhydrous CH3CN with 20:80 F2:N2 is reported. It differs significantly from the previously reported procedure in that anhydrous CH3CN (a-CH3CN) replaced anhydrous HF (a-HF) as the solvent and the yield of recrystallized K(B12F11(NH3)) increased from 40% to 70%. It also differs from the published procedure for the direct per-B-fluorination of K2(B12H12) to form K2(B12F12) in CH3CN containing 2% H2O (wet CH3CN) in that (i) a-CH3CN was used instead of wet CH3CN and (ii) addition of excess KF at the start of the reaction to sequester the HF byproduct was deleterious in the case of K(B12H11(NH3)) fluorination, not advantageous as in the case of K2(B12H12) fluorination. The addition of excess KF resulted in decomposition of B12H11−nFn(NH3)− intermediates as the average value of n approached 11, and even small amounts of K(B12F11(NH3)) free of incompletely fluorinated K(B12HF10(NH3)) could not be isolated. In contrast to the direct fluorination of K2(B12H12) in wet CH3CN, which is inhibited by the buildup of HF, the fluorinations of both K(B12H11(NH3)) and K2(B12H12) in a-CH3CN were not inhibited by HF. A competition experiment in which approximatetly equimolar amounts of K(B12H11(NH3)) and K2(B12H12) were fluorinated together in a-CH3CN showed that B–H vertex fluorination was ca. 50% faster for B12H122− than for B12H11(NH3)−. The single-crystal X-ray structures of Na(H2O)4(B12F11(NH3)) and Na(H3O)(H2O)3(B12F12) were determined. They both contain trans-Na(H2O)2F4 moieties, with ranges of Na–O and Na–F distances of 2.331(1)–2.339(1) and 2.264(1)–2.456(1) Å, respectively, in contrast to the cis-Na(H2O)4F2 moieties in the published structure of Na2(H2O)4(B12F12), with ranges of Na–O and Na–F distances of 2.368(9)–2.473(9) and 2.313(8)–2.381(7) Å, respectively. The O atoms of the nearly-square array of four hydrogen-bonded H2O molecules in Na(H2O)4(B12F11(NH3)) or the H3O+ ion and three H2O molecules in Na(H3O)(H2O)3(B12F12) are co-planar to within 0.016 Å and have O⋯O distances of 2.74–2.83 Å and O⋯O⋯O angles of 80–100°.Efficient per-B-fluorination of B12H11(NH3)− and the structure of Na(H2O)4(B12F11(NH3)) are reported and compared with the previously reported per-B-fluorination of B12H122− and the structures of Na(H2O)4(B12F12) and Na(H3O)(H2O)3(B12F12).Download high-res image (87KB)Download full-size image

Structures of M2(SO2)6B12F12 (M = Ag or K) and Ag2(H2O)4B12F12: Comparison of the Coordination of SO2 versus H2O and of B12F122– versus Other Weakly Coordinating Anions to Metal Ions in the Solid State

Co-reporter:Moritz Malischewski, Dmitry V. Peryshkov, Eric V. Bukovsky, Konrad Seppelt, and Steven H. Strauss

Inorganic Chemistry 2016 Volume 55(Issue 23) pp:12254-12262

Publication Date(Web):November 14, 2016

DOI:10.1021/acs.inorgchem.6b01980

The structures of three solvated monovalent cation salts of the superweak anion B12F122– (Y2–), K2(SO2)6Y, Ag2(SO2)6Y, and Ag2(H2O)4Y, are reported and discussed with respect to previously reported structures of Ag+ and K+ with other weakly coordinating anions. The structures of K2(SO2)6Y and Ag2(SO2)6Y are isomorphous and are based on expanded cubic close-packed arrays of Y2– anions with M(OSO)6+ complexes centered in the trigonal holes of one expanded close-packed layer of B12 centroids (⊙). The K+ and Ag+ ions have virtually identical bicapped trigonal prism MO6F2 coordination spheres, with M–O distances of 2.735(1)–3.032(2) Å for the potassium salt and 2.526(5)–2.790(5) Å for the silver salt. Each M(OSO)6+ complex is connected to three other cationic complexes through their six μ-SO2-κ1O,κ2O′ ligands. The structure of Ag2(H2O)4Y is unique [different from that of K2(H2O)4Y]. Planes of close-packed arrays of anions are offset from neighboring planes along only one of the linear ⊙···⊙···⊙ directions of the close-packed arrays, with [Ag(μ-H2O)2Ag(μ-H2O)2)]∞ infinite chains between the planes of anions. There are two nearly identical AgO4F2 coordination spheres, with Ag–O distances of 2.371(5)–2.524(5) Å and Ag–F distances of 2.734(4)–2.751(4) Å. This is only the second structurally characterized compound with four H2O molecules coordinated to a Ag+ ion in the solid state. Comparisons with crystalline H2O and SO2 solvates of other Ag+ and K+ salts of weakly coordinating anions show that (i) N[(SO2)2(1,2-C6H4)]−, BF4–, SbF6–, and Al(OC(CF3)3)4– coordinate much more strongly to Ag+ than does Y2–, (ii) SnF62– coordinates somewhat more strongly to K+ than does Y2–, and (iii) B12Cl122– coordinates to K+ about the same as, if not slightly weaker than, Y2–.

Structures and structure-related electronic properties of new C60(CF3)10 isomers

Co-reporter:Eric V. Bukovsky, Bryon W. Larson, Tyler T. Clikeman, Yu-Sheng Chen, Alexey A. Popov, Olga V. Boltalina, Steven H. Strauss

Journal of Fluorine Chemistry 2016 Volume 185() pp:103-117

Publication Date(Web):May 2016

DOI:10.1016/j.jfluchem.2016.02.007

•Addition patterns of eight isomers of C60(CF3)10 are confirmed by X-ray crystallography.•The CF3 groups are arranged in the para or meta positions on fullerene hexagons.•Reduction potentials for the isomers vary by 0.53 V, a record for fullerene derivative isomers.•DFT calculations show that the LUMOs are directly connected to the placement of double bonds in fullerene pentagons.The largest collection of well-characterized homoleptic fullerene derivatives C60(X)n is for X = CF3 and n = 2–18. The largest subset of these with a given composition is the set of 27 isomers of C60(CF3)10. The X-ray structures of five of them were reported previously. In this paper we report the X-ray structures of, and extensive DFT calculations on, eight additional C60(CF3)10 isomers and the electrochemical reduction potentials of eight of the (now) 13 structurally-characterized isomers. The connections between their molecular structures (i.e., their addition patterns), the positions, extents of delocalization, and relative energies of their DFT-predicted LUMOs, and their first reduction potentials are compared and contrasted with each other and with the previously reported isomers. It is shown that addition patterns that produce the greatest number of non-terminal double bonds in fullerene pentagons are the best electron acceptors and tend to exhibit relatively small HOMO–LUMO gaps. A detailed analysis of the nearest-neighbor packing patterns in the 13 X-ray structures reveals significant differences in the number of nearest neighbor fullerene molecules and differences in the ranges of fullerene centroid⋯centroid distances even when the number of nearest neighbors is constant. Nevertheless, ten solvent-free structures exhibit nearly equally-efficient lattice packing arrays as far as crystal density is concerned. When the addition pattern results in two sterically-accessible C(sp2)6 hexagons on the fullerene surface, a one-dimensional chain of electronically-coupled nearest-neighbor C60(CF3)10 molecules is formed.Molecular and electronic structures of 13 isomers of C60(CF3)10 are analyzed, including eight new X-ray structures.

Frontispiece: Incremental Tuning Up of Fluorous Phenazine Acceptors

Co-reporter:Dr. Karlee P. Castro;Dr. Tyler T. Clikeman;Nicholas J. DeWeerd;Dr. Eric V. Bukovsky;Kerry C. Rippy;Dr. Igor V. Kuvychko;Dr. Gao-Lei Hou;Dr. Yu-Sheng Chen;Dr. Xue-Bin Wang;Dr. Steven H. Strauss;Dr. Olga V. Boltalina

Chemistry - A European Journal 2016 Volume 22( Issue 12) pp:

Publication Date(Web):

DOI:10.1002/chem.201504564

Incremental Tuning Up of Fluorous Phenazine Acceptors

Chemistry - A European Journal 2016 Volume 22( Issue 12) pp:3930-3936

Publication Date(Web):

DOI:10.1002/chem.201504122

Abstract

In a simple, one-step direct trifluoromethylation of phenazine with CF₃I we prepared and characterized nine (poly)trifluoromethyl derivatives with up to six CF₃ groups. The electrochemical reduction potentials and gas-phase electron affinities show a direct, strict linear relation to the number of CF₃ groups, with phenazine(CF₃)₆ reaching a record-high electron affinity of 3.24 eV among perfluoroalkylated polyaromatics.

Perfluoroalkylfullerenes

Co-reporter:Olga V. Boltalina, Alexey A. Popov, Igor V. Kuvychko, Natalia B. Shustova, and Steven H. Strauss

Chemical Reviews 2015 Volume 115(Issue 2) pp:1051

Publication Date(Web):January 15, 2015

DOI:10.1021/cr5002595

A faux hawk fullerene with PCBM-like properties

Co-reporter:Long K. San, Eric V. Bukovsky, Bryon W. Larson, James B. Whitaker, S. H. M. Deng, Nikos Kopidakis, Garry Rumbles, Alexey A. Popov, Yu-Sheng Chen, Xue-Bin Wang, Olga V. Boltalina and Steven H. Strauss

Chemical Science 2015 vol. 6(Issue 3) pp:1801-1815

Publication Date(Web):16 Dec 2014

DOI:10.1039/C4SC02970D

Reaction of C60, C6F5CF2I, and SnH(n-Bu)3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C60(CF2C6F5)H (1) and 1,9-C60(cyclo-CF2(2-C6F4)) (2). The highest isolated yield of 1 was 35% based on C60. Depending on the reaction conditions, the relative amounts of 1 and 2 generated in situ were as high as 85% and 71%, respectively, based on HPLC peak integration and summing over all fullerene species present other than unreacted C60. Compound 1 is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to 2 upon addition of Sn2(n-Bu)6 at this temperature. In contrast, complete conversion of 1 to 2 occurred within minutes, or hours, at 25 °C in 90/10 (v/v) PhCN/C6D6 by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp2). DFT calculations indicate that when 1 is deprotonated, the anion C60(CF2C6F5)− can undergo facile intramolecular SNAr annulation to form 2 with concomitant loss of F−. To our knowledge this is the first observation of a fullerene-cage carbanion acting as an SNAr nucleophile towards an aromatic C–F bond. The gas-phase electron affinity (EA) of 2 was determined to be 2.805(10) eV by low-temperature PES, higher by 0.12(1) eV than the EA of C60 and higher by 0.18(1) eV than the EA of phenyl-C61-butyric acid methyl ester (PCBM). In contrast, the relative E1/2(0/−) values of 2 and C60, −0.01(1) and 0.00(1) V, respectively, are virtually the same (on this scale, and under the same conditions, the E1/2(0/−) of PCBM is −0.09 V). Time-resolved microwave conductivity charge-carrier yield × mobility values for organic photovoltaic active-layer-type blends of 2 and poly-3-hexylthiophene (P3HT) were comparable to those for equimolar blends of PCBM and P3HT. The structure of solvent-free crystals of 2 was determined by single-crystal X-ray diffraction. The number of nearest-neighbor fullerene–fullerene interactions with centroid⋯centroid (⊙⋯⊙) distances of ≤10.34 Å is significantly greater, and the average ⊙⋯⊙ distance is shorter, for 2 (10 nearest neighbors; ave. ⊙⋯⊙ distance = 10.09 Å) than for solvent-free crystals of PCBM (7 nearest neighbors; ave. ⊙⋯⊙ distance = 10.17 Å). Finally, the thermal stability of 2 was found to be far greater than that of PCBM.

Fullerene cyanation does not always increase electron affinity: an experimental and theoretical study

Co-reporter:Tyler T. Clikeman, Shihu H. M. Deng, Alexey A. Popov, Xue-Bin Wang, Steven H. Strauss and Olga V. Boltalina

Physical Chemistry Chemical Physics 2015 vol. 17(Issue 1) pp:551-556

Publication Date(Web):07 Nov 2014

DOI:10.1039/C4CP04287E

The electron affinities of C70 derivatives with trifluoromethyl, methyl and cyano groups were studied experimentally and theoretically using low-temperature photoelectron spectroscopy (LT PES) and density functional theory (DFT). The electronic effects of these functional groups were determined and found to be highly dependent on the addition patterns. Substitution of CF3 for CN for the same addition pattern increases the experimental electron affinity by 70 meV per substitution. The synthesis of a new fullerene derivative, C70(CF3)10(CN)2, is reported for the first time.

Core Perylene Diimide Designs via Direct Bay- and ortho-(Poly)trifluoromethylation: Synthesis, Isolation, X-ray Structures, Optical and Electronic Properties

Co-reporter:Tyler T. Clikeman;Eric V. Bukovsky;Xue-Bin Wang;Yu-Sheng Chen;Garry Rumbles;Olga V. Boltalina

European Journal of Organic Chemistry 2015 Volume 2015( Issue 30) pp:6641-6654

Publication Date(Web):

DOI:10.1002/ejoc.201501024

Abstract

We developed an efficient solvent- and catalyst-free direct polytrifluoromethylation of solid perylene-3,4,9,10-tetracarboxylic dianhydride that produced a new family of (poly)perfluoroalkyl bay- and ortho-substituted PDIs with two different imide substituents. Direct hydrogen substitution with CN group led to the synthesis of a cyanated perfluoroalkyl PDI derivative for the first time. Absorption, steady-state and time-resolved emission, X-ray diffraction, electrochemical, and gas-phase electron affinity data allowed for systematic studies of substitution effects at bay, ortho, and imide positions in the new PDIs. Solid-state packing showed remarkable variations in the intermolecular interactions that are important for charge transport and photophysical properties. Analysis of the electrochemical data for 143 electron poor PDIs, including newly reported compounds, revealed some general trends and peculiar effects from substituting electron-withdrawing groups at all three positions.

Poly(trifluoromethyl)azulenes: structures and acceptor properties

Co-reporter:Tyler T. Clikeman, Eric V. Bukovsky, Igor V. Kuvychko, Long K. San, Shihu H. M. Deng, Xue-Bin Wang, Yu-Sheng Chen, Steven H. Strauss and Olga V. Boltalina

Chemical Communications 2014 vol. 50(Issue 47) pp:6263-6266

Publication Date(Web):08 Apr 2014

DOI:10.1039/C4CC00510D

Six new poly(trifluoromethyl)azulenes prepared in a single high-temperature reaction exhibit strong electron accepting properties in the gas phase and in solution and demonstrate the propensity to form regular π-stacked columns in donor–acceptor crystals when mixed with pyrene as a donor.

An elusive fulvene 1,7,11,24-C60(CF3)4 and its unusual reactivity

Co-reporter:James B. Whitaker, Igor V. Kuvychko, Natalia B. Shustova, Yu-Sheng Chen, Steven H. Strauss and Olga V. Boltalina

Chemical Communications 2014 vol. 50(Issue 10) pp:1205-1208

Publication Date(Web):22 Nov 2013

DOI:10.1039/C3CC47899H

The X-ray crystal structure of a trifluoromethylfullerene (TMF), 1,7,11,24-C60(CF3)4, is reported for the first time. This elusive intermediate, while highly air stable as a solid, exhibits highly regioselective reactivity towards molecular oxygen in polar solvents, and only when exposed to light.

Single-Step Gas-Phase Polyperfluoroalkylation of Naphthalene Leads to Thermodynamic Products

Co-reporter:Long K. San;Eric V. Bukovsky;Dr. Igor V. Kuvychko;Dr. Alexey A. Popov; Steven H. Strauss;Dr. Olga V. Boltalina

Chemistry - A European Journal 2014 Volume 20( Issue 15) pp:4373-4379

Publication Date(Web):

DOI:10.1002/chem.201304554

Abstract

High-temperature gas-phase, solvent- and catalyst-free reaction of naphthalene with an excess of R_FI reagent (R_FCF₃, C₂F₅, n-C₃F₇, and n-C₄F₉) was used for the first time to produce a series of highly perfluoroalkylated naphthalene products NAPH(R_F)_n with n=2–5. Four 95+ % pure 1,3,5,7-NAPH(R_F)₄ with R_FCF₃, C₂F₅, n-C₃F₇, and n-C₄F₉ were isolated using a simple chromatography-free procedure. These new compounds were fully characterized by ¹⁹F and ¹H NMR spectroscopy, X-ray crystallography (for R_FCF₃ and C₂F₅), atmospheric-pressure chemical ionization mass spectrometry, and cyclic and square-wave voltammetry. DFT calculations confirm that the proposed synthesis yields the most stable isomers that have not been accessed by alternative preparation techniques.

Anion packing, hole filling, and HF solvation in A2(HF)nB12F12 and K2(HF)TiF6 (A = K, Cs)

Co-reporter:Dmitry V. Peryshkov, Roland Friedemann, Evgeny Goreshnik, Zoran Mazej, Konrad Seppelt, Steven H. Strauss

Journal of Fluorine Chemistry 2013 Volume 145() pp:118-127

Publication Date(Web):January 2013

DOI:10.1016/j.jfluchem.2012.10.009

The crystal structures of three new HF solvates of fluoroanion salts of alkali metal ions are reported, K2(HF)TiF6, K2(HF)3B12F12, and Cs2(HF)B12F12. The anion packing in K2(HF)TiF6 (P21/m) is distorted cubic close-packed with Ti⋯Ti distances that range from 5.717(1) to 7.394(1) Å (average 6.18 Å). Half of the K+ ions are in Td holes and half are in Oh holes (i.e., this is a distorted version of the Cs2S structure). Each HF molecule is bonded to a K+ ion in the Oh holes (KF(H) = 2.679(5) Å) and also weakly interacts with two other K+ ions in adjacent Oh holes (K⋯F(H) = 3.238(2) Å). The anion packing in K2(HF)3B12F12 (Fm3¯m) is simple cubic. The (B12 centroid)⋯(B12 centroid) distance (⊙⋯⊙ distance) is 7.242 Å, and disordered K2(μ-HF)32+ cations occupy each cube. The anion packing in Cs2(HF)B12F12 (P21/c) is distorted hexagonal close-packed with ⊙⋯⊙ distances that range from 7.217 to 9.408 Å (average 8.304 Å). The HF molecule bridges Cs+ ions in adjacent Oh holes, forming infinite Cs+(μ-HF)Cs+(μ-HF) chains. The other half of the Cs+ ions are in Td holes, displaced nearly 1 Å from the center of those holes. This structure is similar to the distorted Ni2In structure exhibited by Cs2(H2O)B12F12. The new results are used to compare and contrast the strength of M–F(H) interactions with M–F interactions involving F atoms from fluoroanions as well as the solid-state packing of icosahedral B12F122− anions and octahedral MF62− anions in alkali-metal salts, both with and without the inclusion of weakly-basic HF solvent molecules.Graphical abstractThe crystal structures of three HF solvates of fluoroanion salts of alkali metal ions are reported, K2(HF)TiF6, K2(HF)3B12F12, and Cs2(HF)B12F12. The results are used to compare and contrast the strength of M–F(H) interactions with M–F interactions involving F atoms from fluoroanions as well as the solid-state packing of icosahedral B12F122− anions and octahedral MF62− anions in alkali-metal salts, both with and without the inclusion of weakly-basic HF solvent molecules.Highlights► Three new compounds with HF coordinated to metal ions. ► Crystal structures of TiF62− and B12F122− salts. ► Anion packing and hole filling in fluoroanion salts. ► Simple-cubic packing of B12F122− anions observed for the first time.

Regioselective Sequential Additions of Nucleophiles and Electrophiles to Perfluoroalkylfullerenes: Which Cage C Atoms Are the Most Reactive and Why?

Co-reporter:Tyler T. Clikeman;Dr. Igor V. Kuvychko;Dr. Natalia B. Shustova;Dr. Yu-Sheng Chen;Dr. Alexey A. Popov;Dr. Olga V. Boltalina; Steven H. Strauss

Chemistry - A European Journal 2013 Volume 19( Issue 16) pp:5070-5080

Publication Date(Web):

DOI:10.1002/chem.201203571

Abstract

The sequential addition of CN⁻ or CH₃⁻ and electrophiles to three perfluoroalkylfullerenes (PFAFs), C_s-C₇₀(CF₃)₈, C₁-C₇₀(CF₃)₁₀, and C_s-p-C₆₀(CF₃)₂, was carried out to determine the most reactive individual fullerene C atoms (as opposed to the most reactive CC bonds, which has previously been studied). Each PFAF reacted with CH₃⁻ or CN⁻ to generate metastable PFAF(CN)⁻ or PFAF(CH₃)₂²⁻ species with high regioselectivity (i.e., one or two predominant isomers). They were treated with electrophiles E⁺ to generate PFAF(CN)(E) or PFAF(CH₃)₂(E)₂ derivatives, also with high regioselectivity (E⁺=CN⁺, CH₃⁺, or H⁺). All of the predominant products, characterized by mass spectrometry and ¹⁹F NMR spectroscopy, are new compounds. Some could be purified by HPLC to give single isomers. Two of them, C₇₀(CF₃)₈(CN)₂ and C₇₀(CF₃)₁₀(CH₃)₂(CN)₂, were characterized by single-crystal X-ray diffraction. DFT calculations were used to propose whether a particular reaction is under kinetic or thermodynamic control.

Solid-state solvation and anion packing patterns in X-ray structures of crystalline K2(solv)nB12F12 (solv=H2O2(aq), CH3OH, CH3NO2, and CH3CN)

Co-reporter:Dmitry V. Peryshkov, Eric V. Bukovsky, Travis C. Folsom, Steven H. Strauss

Polyhedron 2013 58() pp: 197-205

Publication Date(Web):

DOI:10.1016/j.poly.2012.11.004

Fullerene Superhalogen Radicals: the Substituent Effect on Electronic Properties of 1,7,11,24,27-C60X5

Co-reporter:Tyler T. Clikeman;Dr. S. H. M. Deng;Dr. Stanislav Avdoshenko;Dr. Xue-Bin Wang;Dr. Alexey A. Popov ; Steven H. Strauss;Dr. Olga V. Boltalina

Chemistry - A European Journal 2013 Volume 19( Issue 45) pp:15404-15409

Publication Date(Web):

DOI:10.1002/chem.201301234

Abstract

Hexasubstituted fullerenes with the skew pentagonal pyramid (SPP) addition pattern are predominantly formed in many types of reactions and represent important and versatile building blocks for supramolecular chemistry, biomedical and optoelectronic applications. Regioselective synthesis and characterization of the new SPP derivative, C₆₀(CF₃)₄(CN)H, in this work led to the experimental identification of the new family of “superhalogen fullerene radicals”, species with the gas-phase electron affinity higher than that of the most electronegative halogens, F and Cl. Low-temperature photoelectron spectroscopy and DFT studies of different C₆₀X₅ radicals reveal a profound effect of X groups on their electron affinities (EA), which vary from 2.76 eV (X=CH₃) to 4.47 eV (X=CN). The measured gas-phase EA of the newly synthesized C₆₀(CF₃)₄CN equals 4.28 (1) eV, which is about 1 eV higher than the EA of Cl atom. An observed remarkable stability of C₆₀(CF₃)₄CN⁻ in solution under ambient conditions opens new venues for design of air-stable molecular complexes and salts for supramolecular structures of electroactive functional materials.

Taming Hot CF3 Radicals: Incrementally Tuned Families of Polyarene Electron Acceptors for Air-Stable Molecular Optoelectronics

Co-reporter:Dr. Igor V. Kuvychko;Karlee P. Castro;S. H. M. Deng;Dr. Xue-Bin Wang; Steven H. Strauss;Dr. Olga V. Boltalina

Angewandte Chemie International Edition 2013 Volume 52( Issue 18) pp:4871-4874

Publication Date(Web):

DOI:10.1002/anie.201300085

C20H4(C4F8)3: A Fluorine-Containing Annulated Corannulene that Is a Better Electron Acceptor Than C60

Co-reporter:Dr. Igor V. Kuvychko;Cristina Dubceac;Dr. Shihu H. M. Deng;Dr. Xue-Bin Wang;Dr. Alexer A. Granovsky;Dr. Alexey A. Popov; Marina A. Petrukhina; Steven H. Strauss;Dr. Olga V. Boltalina

Angewandte Chemie International Edition 2013 Volume 52( Issue 29) pp:7505-7508

Publication Date(Web):

DOI:10.1002/anie.201300796

Perfluoroalkyl [70]-Fullerenes as Robust Highly-Luminescent Fluorocarbons, or Position of One CF3 Group Matters

Co-reporter:Karlee P. Castro, Yuhuan Jin, Jeffrey J. Rack, Steven H. Strauss, Olga V. Boltalina, and Alexey A. Popov

The Journal of Physical Chemistry Letters 2013 Volume 4(Issue 15) pp:2500-2507

Publication Date(Web):July 10, 2013

DOI:10.1021/jz401068t

The photophysical properties of two C70(CF3)8 and three C70(CF3)10 isomers were studied using steady-state and time-resolved absorption and fluorescence spectroscopy. Four of the compounds exhibited quantum yields (ΦF) higher than for any C70 derivative reported to date, and three exceeded 0.24, the highest ΦF reported for any fullerene or fullerene derivative. A difference in the location of only one CF3 group in C70(CF3)8 and C70(CF3)10 isomers resulted in 200-fold and 14-fold increases in ΦF, respectively. The isomer of C70(CF3)10 with the highest ΦF (0.68 in toluene) also exhibited the longest fluorescence lifetime, 51 ns, thus competing favorably in its luminescent properties with the most luminescent carbon materials studied to date. Formation of the S1 state in one of the C70(CF3)10 isomers occurred within 0.6 ps and its nanosecond-long decay was monitored by ultrafast transient absorption spectroscopy. Time-dependent density functional theory calculations were performed to provide a physically meaningful understanding of the photophysical properties of C70(CF3)n derivatives.Keywords: fluorescence; fullerene; graphene quantum dots; perfluoroalkylation; quantum yield;

Electron Affinity of Phenyl–C61–Butyric Acid Methyl Ester (PCBM)

Co-reporter:Bryon W. Larson, James B. Whitaker, Xue-Bin Wang, Alexey A. Popov, Garry Rumbles, Nikos Kopidakis, Steven H. Strauss, and Olga V. Boltalina

The Journal of Physical Chemistry C 2013 Volume 117(Issue 29) pp:14958-14964

Publication Date(Web):June 5, 2013

DOI:10.1021/jp403312g

The gas-phase electron affinity (EA) of phenyl–C61–butyric acid methyl ester (PCBM), one of the best-performing electron acceptors in organic photovoltaic devices, was measured by low-temperature photoelectron spectroscopy for the first time. The obtained value of 2.63(1) eV is only ca. 0.05 eV lower than that of C60 (2.683(8) eV), compared to a 0.09 V difference in their E1/2 values measured in this work by cyclic voltammetry. Literature E(LUMO) values for PCBM that are typically estimated from cyclic voltammetry and commonly used as a quantitative measure of acceptor properties are dispersed over a wide range between −4.38 and −3.62 eV; the reasons for such a huge discrepancy are analyzed here, and a protocol for reliable and consistent estimations of relative fullerene-based acceptor strength in solution is proposed.

Structures of 1,1′,3,3′-Tetra(2-methyl-2-nonyl)ferrocenium(1+) Oxoanion(1−) Salts. Layered Materials with Alternating Ionic and Low-Dielectric Paraffin-Like Domains Through Which Anion Diffusion is Rapid

Co-reporter:Brady J. Clapsaddle, Samira Caamaño, Gretchen N. Hebert, Michael B. Bayless, Yoshihiro Kobayashi, Susie M. Miller, Oren P. Anderson, and Steven H. Strauss

Crystal Growth & Design 2012 Volume 12(Issue 8) pp:3868-3877

Publication Date(Web):May 30, 2012

DOI:10.1021/cg3000872

The unprecedented interdigitated and layered structures of 1,1′,3,3′-tetra(2-methyl-2-nonyl)ferrocene (DEC) and the oxoanion ferrocenium salts DEC+NO3–, DEC+ClO4–, and DEC+ReO4– were determined by single-crystal X-ray diffraction. The four structures are similar except that the three DEC+ salts have layers of XOn– oxoanions stuffed between the layers of interdigitated ferrocenium ions. The perpendicular distances between layers of Fe atoms are 8.530, 9.108, 9.009, and 9.158 Å for DEC, DEC+NO3–, DEC+ClO4–, and DEC+ReO4–, respectively. The structures also contain layers of rigorously coplanar Fe and X atoms that are tilted 65.4, 75.9, 61.9, and 61.1° from the aforementioned layers of Fe atoms for DEC, DEC+NO3–, DEC+ClO4–, and DEC+ReO4–, respectively. The local environments of the XOn– oxoanions consist of networks of C–H···O hydrogen bonds, and the structures exhibit channels through which these anions could diffuse. Facile diffusion of these anions in thin films of DEC+XOn–, with structures that appear to resemble the crystal structures, has been demonstrated.

The Structure of (H3O)2B12F126H2O a CCP Lattice of B12F122 Anions Intercalated with a Nonplanar Network of OHO Connected O6 Rings

Co-reporter:Eric V. Bukovsky;Stephanie R. Fiedler;Dmitry V. Peryshkov;Alexey A. Popov

European Journal of Inorganic Chemistry 2012 Volume 2012( Issue 2) pp:208-212

Publication Date(Web):

DOI:10.1002/ejic.201101118

Abstract

Hydrates of the dihydronium salt of the superweak anion B₁₂F₁₂^2– have been synthesized and structurally characterized. The structure of (H₃O)₂B₁₂F₁₂·6H₂O consists of a cubic close-packed (CCP) array of B₁₂F₁₂^2– anions intercalated with nonplanar, infinite networks of O₆ rings composed of H₃O⁺ ions and H₂O molecules. Similar to other salts of B₁₂F₁₂^2–, (H₃O)₂B₁₂F₁₂·6H₂O exhibits rapid structural modification, termed latent porosity, and reversibly desorbswater to form other hydrate phases: (H₃O)₂B₁₂F₁₂·4H₂O,(H₃O)₂B₁₂F₁₂·2H₂O, and (H₃O)₂B₁₂F₁₂. (H₃O)₂B₁₂F₁₂·6H₂O is another example of the weak coordinating properties of the B₁₂F₁₂^2– anion.

Synthesis, structure, and reactivity of AlMe2(1-Me-CB11F11): An AlMe2+ cation-like species bonded to a superweak anion

Co-reporter:Sergei V. Ivanov, Dmitry V. Peryshkov, Susie M. Miller, Oren P. Anderson, Anthony K. Rappé, Steven H. Strauss

Journal of Fluorine Chemistry 2012 Volume 143() pp:99-102

Publication Date(Web):November 2012

DOI:10.1016/j.jfluchem.2012.02.001

Treatment of AlMe3 with [CPh3][1-Me-CB11F11] in toluene produced the dimeric compound [AlMe2(1-Me-CB11F11)]2 in 89% isolated yield. The compound was characterized by 1H and 19F NMR spectroscopy and by single crystal X-ray diffraction. The structure consists of a AlMe2+ cation-like species bonded to two F atoms from two 1-Me-CB11F11− superweak anions, forming an AlMe2F2 coordination unit with the unusually large H3C–Al–CH3 angle of 147.6(2)° (cf. the corresponding angle of 117.1(1)° in the AlMe2F2− anion in [N(n-Bu)4][AlMe2F2]). This large angle is due in part to the long Al–F distances of 1.922(3) and 1.928(3) Å (cf. 1.711(1) and 1.7113(1) Å in [N(n-Bu)4][AlMe2F2]), which is why the dimethylaluminum moieties in [AlMe2(1-Me-CB11F11)]2 should possess a considerable degree of positive charge and should be considered as cation-like AlMe2+ species.Graphical abstractTreatment of AlMe3 with [CPh3][1-Me-CB11F11] in toluene produced the dimeric compound [AlMe2(1-Me-CB11F11)]2. The structure consists of AlMe2+ cation-like species bonded to two F atoms from two 1-Me-CB11F11− superweak anions, forming an AlMe2F2 coordination unit with the unusually large H3C–Al–CH3 angle of 147.6(2).Highlights► Synthesis of [AlMe2(1-Me-CB11F11)]2. ► X-ray structure of [AlMe2(1-Me-CB11F11)]2, which consists of AlMe2+ cation-like species bonded to two F atoms from two 1-Me-CB11F11− superweak anions. ► [AlMe2(1-Me-CB11F11)]2 undergoes rapid exchange on the NMR timescale with both AlMe3 and [N(n-Bu)4][1-Me-CB11F11].

A Buckybowl with a Lot of Potential: C5-C20H5(CF3)5

Co-reporter:Dr. Igor V. Kuvychko;Sarah N. Spisak;Dr. Yu-Sheng Chen;Dr. Alexey A. Popov; Marina A. Petrukhina; Steven H. Strauss;Dr. Olga V. Boltalina

Angewandte Chemie International Edition 2012 Volume 51( Issue 20) pp:4939-4942

Publication Date(Web):

DOI:10.1002/anie.201200178

Poly(perfluoroalkylation) of Metallic Nitride Fullerenes Reveals Addition-Pattern Guidelines: Synthesis and Characterization of a Family of Sc3N@C80(CF3)n (n = 2−16) and Their Radical Anions

Co-reporter:Natalia B. Shustova ; Dmitry V. Peryshkov ; Igor V. Kuvychko ; Yu-Sheng Chen ; Mary A. Mackey ; Curtis E. Coumbe ; David T. Heaps ; Bridget S. Confait ; Thomas Heine ; J. Paige Phillips ; Steven Stevenson ; Lothar Dunsch ; Alexey A. Popov ; Steven H. Strauss ;Olga V. Boltalina

Journal of the American Chemical Society 2011 Volume 133(Issue 8) pp:2672-2690

Publication Date(Web):February 4, 2011

DOI:10.1021/ja109462j

A family of highly stable (poly)perfluoroalky-lated metallic nitride cluster fullerenes was prepared in high-temperature reactions and characterized by spectroscopic (MS, 19F NMR, UV−vis/NIR, ESR), structural and electrochemical methods. For two new compounds, Sc3N@C80(CF3)10 and Sc3N@C80(CF3)12, single crystal X-ray structures are determined. Addition pattern guidelines for endohedral fullerene derivatives with bulky functional groups are formulated as a result of experimental (19F NMR spectroscopy and single crystal X-ray diffraction) studies and exhaustive quantum chemical calculations of the structures of Sc3N@C80(CF3)n (n = 2-16). Electrochemical studies revealed that Sc3N@C80(CF3)n derivatives are easier to reduce than Sc3N@C80, the shift of E1/2 potentials ranging from +0.11 V (n = 2) to +0.42 V (n = 10). Stable radical anions of Sc3N@C80(CF3)n were generated in solution and characterized by ESR spectroscopy, revealing their 45Sc hyperfine structure. Facile further functionalizations via cycloadditions or radical additions were achieved for trifluoromethylated Sc3N@C80 making them attractive versatile platforms for the design of molecular and supramolecular materials of fundamental and practical importance.

Chemical tailoring of fullerene acceptors: synthesis, structures and electrochemical properties of perfluoroisopropylfullerenes

Co-reporter:Natalia B. Shustova, Igor V. Kuvychko, Dmitry V. Peryshkov, James B. Whitaker, Bryon W. Larson, Yu-Sheng Chen, Lothar Dunsch, Konrad Seppelt, Alexey A. Popov, Steven H. Strauss and Olga V. Boltalina

Chemical Communications 2011 vol. 47(Issue 3) pp:875-877

Publication Date(Web):09 Nov 2010

DOI:10.1039/C0CC03247F

High-temperature syntheses of the new C60(i-C3F7)2,4,6 and C70(i-C3F7)2,4 isomers and their characterization by spectroscopic methods, X-ray crystallography, cyclic voltammetry and density functional theory provide compelling evidence that they are superior electron acceptors than trifluoromethylfullerenes.

Pressure effect on heterogeneous trifluoromethylation of fullerenes and its application

Co-reporter:Igor V. Kuvychko, James B. Whitaker, Bryon W. Larson, Rachel S. Raguindin, Kristin J. Suhr, Steven H. Strauss, Olga V. Boltalina

Journal of Fluorine Chemistry 2011 Volume 132(Issue 10) pp:679-685

Publication Date(Web):October 2011

DOI:10.1016/j.jfluchem.2011.03.008

The first systematic study of heterogeneous fullerene trifluoromethylation using an innovative gradient-temperature gas–solid reactor revealed a significant effect of CF3I pressure on the conversion of C60 and C70 into trifluoromethylated products and on the range of fullerene(CF3)n compositions that were obtained. The design of the reactor allowed us to lower the residence times of fullerene(CF3)n species in the hot zone which resulted in the significant differences in relative isomeric distributions as compared to the earlier methods. For the first time, gram quantities of trifluoromethylated fullerenes were prepared using the new reactor, and the selective synthesis of a single-isomer C60(CF3)2 was developed. The relative reactivity of C70 as a CF3 radical scavenger was found to be much lower than that of C60, especially at an early radical addition stage, which led to the cost-efficient synthesis of C60(CF3)2 from a fullerene extract.Graphical abstractThe first systematic study of heterogeneous fullerene trifluoromethylation using an innovative gradient-temperature gas–solid reactor revealed a significant effect of CF3I pressure on the conversion and on the range of fullerene(CF3)n compositions. The selective synthesis of a single-isomer C60(CF3)2 was developed.Highlights► Significant improvements in understanding of heterogeneous trifluoromethylation of fullerenes. ► Preparation of trifluoromethylated fullerenes in hundreds of mg. ► Effect of gas pressure has been studied using an original gradient-temperature-gas–solid reactor. ► Selective preparation of bis-trifluoromethylated C60, using “low-conversion regime”, including an economical method with the use of inexpensive fullerene extract. ► We discovered that C70 has much lower reactivity towards CF3 radical addition than C60.

Pairing heterocyclic cations with closo-dodecafluorododecaborate (2−): Synthesis of binary heterocyclium(1+) salts and a Ag4(heterocycle)84+ salt of B12F122−

Co-reporter:John L. Belletire, Stefan Schneider, Scott A. Shackelford, Dmitry V. Peryshkov, Steven H. Strauss

Journal of Fluorine Chemistry 2011 Volume 132(Issue 11) pp:925-936

Publication Date(Web):November 2011

DOI:10.1016/j.jfluchem.2011.07.009

Eight binary salts that pair triazolium(1+), imidazolium(1+), pyrimidinium(1+), or purinium(1+) cations with the icosahedral closo-dodecafluorododecaborate(2−) anion (B12F122−) were synthesized using open-air benchtop metathesis reactions in water or acetonitrile. The scale of the reactions varied from just milligrams to nearly one gram of the K2B12F12 starting material. Other reaction conditions, the scope of the reaction, and the solubilities for the new salts are discussed. Five [heterocyclium]2[B12F12] salts, which were obtained in yields ranging from 84% to 99%, displayed significantly higher densities than the corresponding previously reported analogous [heterocyclium]2[B12H12] and [heterocyclium][CB11H12] salts. A ninth high-density salt consisted of B12F122− paired with a complex Ag4(triazole)84+ cation. The structures of eight of the nine new compounds were determined by single-crystal X-ray diffraction analysis. The density of five [heterocyclium]2[B12F12] salts was found to increase approximately linearly as the distance between the five-membered-ring heterocyclium(1+) cation centroids decreased. This work demonstrates additional flexibility for the rational design of ionic structures with predictable properties, which will ultimately permit the tailoring of ingredient-response behavior.Graphical abstractDescribed are the first syntheses and single-crystal X-ray diffraction characterization of eight binary [heterocyclium]2[B12F12] salts and a complex [Ag4(heterocycle)8][B12F12]2 salt.Highlights► First synthesis of heterocyclium icosahedral perfluoroborane salts: [heterocyclium]2[closo-B12F12]. ► Unique salt [Ag4(heterocycle)8][B12F12]2 isolated containing the [Ag4(heterocycle)8]4+ tetracation. ► Open-air benchtop synthesis using standard chemical glassware with H2O or CH3CN solvent. ► Linear correlation between salt density and cat⋯cat separation was discovered by X-ray analyses.

In Search of Fullerene-Based Superacids: Synthesis, X-ray Structure, and DFT Study of C60(C2F5)5H

Co-reporter:Dr. Igor V. Kuvychko;Dr. Natalia B. Shustova;Dr. Stanislav M. Avdoshenko;Dr. Alexey A. Popov;Dr. Steven H. Strauss;Dr. Olga V. Boltalina

Chemistry - A European Journal 2011 Volume 17( Issue 32) pp:8799-8802

Publication Date(Web):

DOI:10.1002/chem.201101328

Cover Picture: Nitrogen Directs Multiple Radical Additions to the 9,9-Bi-1-aza(C60-Ih)[5,6]fullerene: X-ray Structure of 6,9,12,15,18-C59N(CF3)5 (Angew. Chem. Int. Ed. 24/2011)

Co-reporter:Dr. Natalia B. Shustova;Dr. Igor V. Kuvychko;Dr. Alexey A. Popov;Max vonDelius; Lothar Dunsch; Oren P. Anderson;Dr. Andreas Hirsch; Steven H. Strauss;Dr. Olga V. Boltalina

Angewandte Chemie International Edition 2011 Volume 50( Issue 24) pp:

Publication Date(Web):

DOI:10.1002/anie.201102438

Nitrogen Directs Multiple Radical Additions to the 9,9-Bi-1-aza(C60-Ih)[5,6]fullerene: X-ray Structure of 6,9,12,15,18-C59N(CF3)5

Co-reporter:Dr. Natalia B. Shustova;Dr. Igor V. Kuvychko;Dr. Alexey A. Popov;Max vonDelius; Lothar Dunsch; Oren P. Anderson;Dr. Andreas Hirsch; Steven H. Strauss;Dr. Olga V. Boltalina

Angewandte Chemie International Edition 2011 Volume 50( Issue 24) pp:5537-5540

Publication Date(Web):

DOI:10.1002/anie.201101227

Latent Porosity in Potassium Dodecafluoro-closo-dodecaborate(2−). Structures and Rapid Room Temperature Interconversions of Crystalline K2B12F12, K2(H2O)2B12F12, and K2(H2O)4B12F12 in the Presence of Water Vapor

Co-reporter:Dmitry V. Peryshkov ; Alexey A. Popov

Journal of the American Chemical Society 2010 Volume 132(Issue 39) pp:13902-13913

Publication Date(Web):September 10, 2010

DOI:10.1021/ja105522d

Structures of K2(H2O)2B12F12 and K2(H2O)4B12F12 were determined by X-ray diffraction. They contain [K(μ-H2O)2K]2+ and [(H2O)K(μ-H2O)2K(H2O)]2+ dimers, respectively, which interact with superweak B12F122− anions via multiple K···F(B) interactions and (O)H···F(B) hydrogen bonds (the dimers in K2(H2O)4B12F12 are also linked by (O)H···O hydrogen bonds). DFT calculations show that both dimers are thermodynamically stabilized by the lattice of anions: the predicted ΔE values for the gas-phase dimerization of two K(H2O)+ or K(H2O)2+ cations into [K(μ-H2O)2K]2+ or [(H2O)K(μ-H2O)2K(H2O)]2+ are +232 and +205 kJ mol−1, respectively. The calculations also predict that ΔE for the gas-phase reaction 2 K+ + 2 H2O → [K(μ-H2O)2K]2+ is +81.0 kJ mol, whereas ΔH for the reversible reaction K2B12F12 (s) + 2 H2O(g) → K2(H2O)2B12F12 (s) was found to be −111 kJ mol−1 by differential scanning calorimetry. The K2(H2O)0,2,4B12F12 system is unusual in how rapidly the three crystalline phases (the K2B12F12 structure was reported recently) are interconverted, two of them reversibly. Isothermal gravimetric and DSC measurements showed that the reaction K2B12F12 (s) + 2 H2O(g) → K2(H2O)2B12F12 (s) was complete in as little as 4 min at 25 °C when the sample was exposed to a stream of He or N2 containing 21 Torr H2O(g). The endothermic reverse reaction required as little as 18 min when K2(H2O)2B12F12 at 25 °C was exposed to a stream of dry He. The products of hydration and dehydration were shown to be crystalline K2(H2O)2B12F12 and K2B12F12, respectively, by PXRD, and therefore these reactions are reconstructive solid-state reactions (there is also evidence that they may be single-crystal-to-single-crystal transformations when carried out very slowly). The hydration and dehydration reaction times were both particle-size dependent and carrier-gas flow rate dependent and continued to decrease up to the maximum carrier-gas flow rate of the TGA instrument that was used, demonstrating that the hydration and dehydration reactions were limited by the rate at which H2O(g) was delivered to or swept away from the microcrystal surfaces. Therefore, the rates of absorption and desorption of H2O from unit cells at the surface of the microcrystals, and the rate of diffusion of H2O across the moving K2(H2O)2B12F12 (s)/K2B12F12 (s) phase boundary, are even faster than the fastest rates of change in sample mass due to hydration and dehydration that were measured. The exchange of 21 Torr H2O(g) with either D2O or H218O in microcrystalline K2(D2O)2B12F12 or K2(H218O)2B12F12 at 25 °C was also facile and required as little as 45 min to go to completion (H2O(g) replaced both types of isotopically labeled water at the same rate for a given starting sample of K2B12F12, demonstrating that water molecules were exchanging, not protons. Significant portions of mass (m) vs time (t) plots for the 1,2H2O(g)/K2(2,1H2O)2B12F12 (s) exchange reactions fit the equation m ∝ e−kt, with 103k = 1.9 s−1 for one particle size distribution and 103k = 0.50 s−1 for another. Finally, K2(H2O)2B12F12 was not transformed into K2(H2O)4B12F12 after prolonged exposure to 21 Torr H2O(g) at 25 °C, 37 Torr H2O(g) at 35 °C, or 55 Torr H2O(g) at 45 °C.

Unraveling the Electron Spin Resonance Pattern of Nonsymmetric Radicals with 30 Fluorine Atoms: Electron Spin Resonance and Vis−Near-Infrared Spectroelectrochemistry of the Anion Radicals and Dianions of C60(CF3)2n (2n = 2−10) Derivatives and Density Functional Theory-Assisted Assignment

Co-reporter:Alexey A. Popov ; Ivan E. Kareev ; Natalia B. Shustova ; Steven H. Strauss ; Olga V. Boltalina ;Lothar Dunsch

Journal of the American Chemical Society 2010 Volume 132(Issue 33) pp:11709-11721

Publication Date(Web):July 28, 2010

DOI:10.1021/ja1043775

The charged states of C60(CF3)2n (2n = 2−10) derivatives have been studied by electron spin resonance (ESR) and vis−near-infrared (NIR) spectroelectrochemistry. The anion radicals and diamagnetic dianions were furthermore described by theoretical calculations. The ESR spectra of anion radicals exhibit complex patterns due to multiple CF3 groups. Their interpretation is accomplished by DFT calculations with B3LYP functional. It is shown that calculations provide reliable results when the extended aug-cc-pCVTZ basis set is used for fluorine atoms; however, specially tailored basis sets such as EPR-III also give very similar results with only a fraction of the computational cost. Absorption spectra of the anions exhibit NIR absorption bands, whose assignment is provided by time-dependent DFT calculations.

Soluble Chlorofullerenes C60Cl2,4,6,8,10. Synthesis, Purification, Compositional Analysis, Stability, and Experimental/Theoretical Structure Elucidation, Including the X-ray Structure of C1-C60Cl10

Co-reporter:Igor V. Kuvychko ; Alexey V. Streletskii ; Natalia B. Shustova ; Konrad Seppelt ; Thomas Drewello ; Alexey A. Popov ; Steven H. Strauss ;Olga V. Boltalina

Journal of the American Chemical Society 2010 Volume 132(Issue 18) pp:6443-6462

Publication Date(Web):April 21, 2010

DOI:10.1021/ja1005256

The efficacy of various analytical techniques for the characterization of products of C60 chlorination reactions were evaluated by (i) using samples of C60Cl6 of known purity and (ii) repeating a number of literature syntheses reported to yield pure C60Cln compounds. The techniques were NMR, UV−vis, IR, and Raman spectroscopy, FAB, MALDI, LDI, ESI, and APCI mass spectrometry, HPLC, TGA, elemental analysis, and single-crystal X-ray diffraction. Most of these techniques are shown to give ambiguous or erroneous results, calling into question the composition and/or purity of nearly all C60Cln compounds reported to date. The optimum analytical method for chlorofullerenes was found to be a combination of HPLC and either MALDI or APCI mass spectrometry. For the first time, the chlorination of C60 by ICl, ICl3, and Cl2 was studied in detail using dynamic HPLC analysis and APCI mass spectrometry. Suitable conditions were found for the preparation of the new chlorofullerenes 1,7-C60Cl2, 1,9-C60Cl2, 1,6,9,18-C60Cl4, and 1,2,7,10,14,24,25,28,29,31-C60Cl10. The latter compound was also studied by 13C NMR spectroscopy and X-ray diffraction, which led to the unambiguous determination of its asymmetric addition pattern. The unusual structure of C60Cl10 was compared with other possible isomers using DFT-predicted relative energies. These results, along with additional experimental data and an analysis of the DFT-predicted frontier orbitals of likely intermediates, were used to rationalize the formation of the new compound C60Cl10 from C60Cl6 and excess ICl without the rearrangement of any C−Cl bonds. For the first time, the stability of C60Cln compounds under a variety of conditions was studied in detail, leading to the discovery that they are, in general, very light-sensitive in solution. The X-ray structure of C60Cl6 was also redetermined with higher precision.

Dynamic HPLC study of C70 chlorination reveals a surprisingly selective synthesis of C70Cl8

Co-reporter:Igor V. Kuvychko, Alexey A. Popov, Alexey V. Streletskii, Leanne C. Nye, Thomas Drewello, Steven H. Strauss and Olga V. Boltalina

Chemical Communications 2010 vol. 46(Issue 43) pp:8204-8206

Publication Date(Web):27 Sep 2010

DOI:10.1039/C0CC03134H

A dynamic HPLC study of C70 chlorination led to the discovery, isolation, characterization, and development of the efficient preparatory procedures for two previously unknown soluble chlorofullerenes C70Cl8 and C70Cl6 and for insoluble [C70Cl8]n. A novel synthesis of 99% pure C70Cl10 with a nearly quantitative yield was also developed. The first stability study of C70Cl10,8,6 in solution showed that these compounds are very light-sensitive.

Co-crystallization of octahedral and icosahedral fluoroanions in K3(AsF6)(B12F12) and Cs3(AsF6)(B12F12). Rare examples of salts containing fluoroanions with different shapes and charges

Co-reporter:Dmitry V. Peryshkov, Evgeny Goreshnik, Zoran Mazej, Steven H. Strauss

Journal of Fluorine Chemistry 2010 Volume 131(Issue 11) pp:1225-1228

Publication Date(Web):November 2010

DOI:10.1016/j.jfluchem.2010.05.009

Crystals grown from anhydrous HF solutions of CsAsF6 and Cs2B12F12 or KAsF6 and Cs2B12F12 are shown by Raman spectroscopy and single-crystal X-ray diffraction to be the ternary salts K3(AsF6)(B12F12) or Cs3(AsF6)(B12F12). Both compounds exhibit a modified version of the anti-perovskite structure. They are rare examples of crystals that simultaneously contain octahedral and icosahedral molecular species and are also rare examples of salts containing fluoroanions with different shapes and charges. The crystallographic results show that both compounds are densely packed.Combining (K,Cs)AsF6 and Cs2B12F12 in HF produced crystals that are shown by Raman spectroscopy and X-ray diffraction to be K3(AsF6)(B12F12) or Cs3(AsF6)(B12F12), which exhibit a modified anti-perovskite structure and are rare examples of crystals that simultaneously contain octahedral and icosahedral species and contain fluoroanions with different shapes and charges.

High-temperature and photochemical syntheses of C60 and C70 fullerene derivatives with linear perfluoroalkyl chains

Co-reporter:Natalia B. Shustova, Ivan E. Kareev, Igor V. Kuvychko, James B. Whitaker, Sergey F. Lebedkin, Alexey A. Popov, Lothar Dunsch, Yu-Sheng Chen, Konrad Seppelt, Steven H. Strauss, Olga V. Boltalina

Journal of Fluorine Chemistry 2010 Volume 131(Issue 11) pp:1198-1212

Publication Date(Web):November 2010

DOI:10.1016/j.jfluchem.2010.08.001

New experimental results on perfluoroalkylation of C60 and C70 with the use of RfI (Rf = CF3, C2F5, n-C3F7, n-C4F9, and n-C6F13), along with a critical overview of the existing synthetic methods, are presented. For the selected new fullerene (Rf)n compounds we report spectroscopic, electrochemical and structural data, including improved crystallographic data for the isomers of C70(C2F5)10 and C60(C2F5)10, and the first X-ray structural data for the dodecasubstituted perfluoethylated C70 fullerene, C70(C2F5)12, which possesses unprecedented addition pattern.New fullerene (Rf)n compounds were prepared in high-temperature reactions, and characterized by spectroscopic, electrochemical and structural methods.

K2B12F12: A rare A2X structure for an ionic compound at ambient conditions

Co-reporter:Dmitry V. Peryshkov, Steven H. Strauss

Journal of Fluorine Chemistry 2010 Volume 131(Issue 11) pp:1252-1256

Publication Date(Web):November 2010

DOI:10.1016/j.jfluchem.2010.06.015

The anhydrous salt K2B12F12 crystallized from aqueous solution and its structure was determined by single crystal X-ray diffraction. The Ni2In-type structure it exhibits is rare for an A2X ionic compound at 25 °C and 1 atm., consisting of an expanded hexagonal close-packed array of B12F122− centroids (cent⋯cent distances: 7.204–8.236 Å) with half of the K+ ions filling all of the Oh holes and half of the K+ ions filling all of the D3h trigonal holes in the close-packed layers that are midway between two “empty” Td holes. The structure is also unusual in that the bond-valence sum for the K+ ions in Oh holes is less than or equal to 0.73 (the bond-valence sum for the other type of K+ ion is 1.16). A variation of the Ni2In structure is exhibited by the previously published monohydrate Cs2(H2O)B12F12, for which an improved structure is also reported here. For K2B12F12: monoclinic, C2/c, a = 8.2072(8), b = 14.2818(7), c = 11.3441(9) Å, β = 92.832(5)°, Z = 4, T = 120(2) K. For Cs2(H2O)B12F12: orthorhombic, P212121, a = 9.7475(4), b = 10.2579(4), c = 15.0549(5) Å, Z = 4, T = 110(1) K.The structure of the K2B12F12, crystallized from an aqueous solution, is extremely rare for an A2X salt. It consists of an expanded HCP array of B12F122− anion centroids with half of the K+ ions filling Oh holes and half filling D3h trigonal holes midway between two “empty” Td holes.

Redox-Tuning Endohedral Fullerene Spin States: From the Dication to the Trianion Radical of Sc3N@C80(CF3)2 in Five Reversible Single-Electron Steps

Co-reporter:AlexeyA. Popov Dr.;NataliaB. Shustova;AnnaL. Svitova;MaryA. Mackey;CurtisE. Coumbe;J.Paige Phillips ;Steven Stevenson ;StevenH. Strauss ;OlgaV. Boltalina Dr.;Lothar Dunsch Dr.

Chemistry - A European Journal 2010 Volume 16( Issue 16) pp:4721-4724

Publication Date(Web):

DOI:10.1002/chem.201000205

Electron DonorAcceptor Interactions in Regioselectively Synthesized exTTF2C70(CF3)10 Dyads

Co-reporter:Yuta Takano;M.Ángeles Herranz Dr.;Nazario Martín Dr.;Gustavo deMiguelRojas Dr.;DirkM. Guldi Dr.;IvanE. Kareev Dr.;StevenH. Strauss Dr.;OlgaV. Boltalina Dr.;Takahiro Tsuchiya Dr.;Takeshi Akasaka Dr.

Chemistry - A European Journal 2010 Volume 16( Issue 18) pp:5343-5353

Publication Date(Web):

DOI:10.1002/chem.200902336

Abstract

The decakis(trifluoromethyl)fullerene C₁-C₇₀(CF₃)₁₀, in which the CF₃ groups are arranged on a para⁷-meta-para ribbon of C₆(CF₃)₂ edge-sharing hexagons, and which has now been prepared in quantities of hundreds of milligrams, was reacted under standard Bingel–Hirsch conditions with a bis-π-extended tetrathiafulvalene (exTTF) malonate derivative to afford a single exTTF₂–C₇₀(CF₃)₁₀ regioisomer in 80 % yield based on consumed starting material. The highly soluble hybrid was thoroughly characterized by using 1D ¹H, ¹³C, and ¹⁹F NMR, 2D NMR, and UV/Vis spectroscopy; matrix-assisted laser desorption ionization (MALDI) mass spectrometry; and electrochemistry. The cyclic voltammogram of the exTTF₂–C₇₀(CF₃)₁₀ dyad revealed an irreversible second reduction process, which is indicative of a typical retro-Bingel reaction; whereas the usual phenomenon of exTTF inverted potentials (>), resulting in a single, two-electron oxidation process, was also observed. Steady-state and time-resolved photolytic techniques demonstrated that the C₁-C₇₀(CF₃)₁₀ singlet excited state is subject to a rapid electron-transfer quenching. The resulting charge-separated states were identified by transient absorption spectroscopy, and radical pair lifetimes of the order of 300 ps in toluene were determined. The exTTF₂–C₇₀(CF₃)₁₀ dyad represents the first example of exploitation of the highly soluble trifluoromethylated fullerenes for the construction of systems able to mimic the photosynthetic process, and is therefore of interest in the search for new materials for photovoltaic applications.

Inside Cover: Redox-Tuning Endohedral Fullerene Spin States: From the Dication to the Trianion Radical of Sc3N@C80(CF3)2 in Five Reversible Single-Electron Steps (Chem. Eur. J. 16/2010)

Co-reporter:AlexeyA. Popov Dr.;NataliaB. Shustova;AnnaL. Svitova;MaryA. Mackey;CurtisE. Coumbe;J.Paige Phillips ;Steven Stevenson ;StevenH. Strauss ;OlgaV. Boltalina Dr.;Lothar Dunsch Dr.

Chemistry - A European Journal 2010 Volume 16( Issue 16) pp:

Publication Date(Web):

DOI:10.1002/chem.201090074

Photoelectron Spectroscopy of C60Fn− and C60Fm2− (n = 17, 33, 35, 43, 45, 47; m = 34, 46) in the Gas Phase and the Generation and Characterization of C1-C60F47− and D2-C60F44 in Solution

Co-reporter:Xue-Bin Wang, Chaoxian Chi, Mingfei Zhou, Igor V. Kuvychko, Konrad Seppelt, Alexey A. Popov, Steven H. Strauss, Olga V. Boltalina and Lai-Sheng Wang

The Journal of Physical Chemistry A 2010 Volume 114(Issue 4) pp:1756-1765

Publication Date(Web):January 8, 2010

DOI:10.1021/jp9097364

A photoelectron spectroscopy investigation of the fluorofullerene anions C60Fn− (n = 17, 33, 35, 43, 45, 47) and the doubly charged anions C60F342− and C60F462− is reported. The first electron affinities for the corresponding neutral molecules, C60Fn, were directly measured and were found to increase as n increased, reaching the extremely high value of 5.66 ± 0.10 eV for C60F47. Density functional calculations suggest that the experimentally observed species C60F17−, C60F35−, and C60F47− were each formed by reductive defluorination of the parent fluorofullerene, C3v-C60F18, C60F36 (a mixture of isomers), and D3-C60F48, respectively, without rearrangement of the remaining fluorine atoms. The DFT-predicted stability of C60F47− was verified by its generation by chemical reduction from D3-C60F48 in chloroform solution at 25 °C and its characterization by mass spectrometry and 19F NMR spectroscopy. Further reductive defluorination of C60F47− in solution resulted in the selective generation of a new fluorofullerene, D2-C60F44, which was also characterized by mass spectrometry and 19F NMR spectroscopy.

Saturnene Revealed: X-ray Crystal Structure of D5d-C60F20 Formed in Reactions of C60 with AxMFy Fluorinating Agents (A=Alkali Metal; M=3d Metal)

Co-reporter:NataliaB. Shustova;Zoran Mazej Dr.;Yu-Sheng Chen Dr.;AlexeyA. Popov Dr.;StevenH. Strauss ;OlgaV. Boltalina Dr.

Angewandte Chemie International Edition 2010 Volume 49( Issue 4) pp:812-815

Publication Date(Web):

DOI:10.1002/anie.200905832

Saturnene Revealed: X-ray Crystal Structure of D5d-C60F20 Formed in Reactions of C60 with AxMFy Fluorinating Agents (A=Alkali Metal; M=3d Metal)

Co-reporter:NataliaB. Shustova;Zoran Mazej Dr.;Yu-Sheng Chen Dr.;AlexeyA. Popov Dr.;StevenH. Strauss ;OlgaV. Boltalina Dr.

Angewandte Chemie 2010 Volume 122( Issue 4) pp:824-827

Publication Date(Web):

DOI:10.1002/ange.200905832

Direct Perfluorination of K2B12H12 in Acetonitrile Occurs at the Gas Bubble−Solution Interface and Is Inhibited by HF. Experimental and DFT Study of Inhibition by Protic Acids and Soft, Polarizable Anions

Co-reporter:Dmitry V. Peryshkov ; Alexey A. Popov

Journal of the American Chemical Society 2009 Volume 131(Issue 51) pp:18393-18403

Publication Date(Web):December 2, 2009

DOI:10.1021/ja9069437

During the optimization of the F2 perfluorination of K2B12H12 in acetonitrile with continuous bubbling of 20/80 F2/N2, it was discovered that (i) HF and other protic acids inhibit each of the 12 fluorination steps (in contradiction to recently published findings) and (ii) the fluorinations appear to take place at the gas bubble−solution interface. Experimental results and DFT calculations suggest that these two phenomena are related by the relative propensities of the various B12H12−xFx2− anions to partition from bulk solution to the interface (i.e., their relative polarizabilities or softness; 0 ≤ x ≤ 12). Relative to the previously reported syntheses of K2B12F12 or Cs2B12F12, the new optimized procedure has the following advantages: (i) the scale was increased 10-fold without sacrificing yield (74% for K2B12F12, 76% for Cs2B12F12) or purity (99.5+%); (ii) the reaction/purification time was decreased from ca. 1 week to 2 days; and (iii) the solvent was changed from anhydrous HF to acetonitrile, allowing ordinary glassware to be used. The anhydrous salt Cs2B12F12 was found to be thermally stable up to 600 °C.

Sc3N@(C80-Ih(7))(CF3)14 and Sc3N@(C80-Ih(7))(CF3)16. Endohedral Metallofullerene Derivatives with Exohedral Addends on Four and Eight Triple-Hexagon Junctions. Does the Sc3N Cluster Control the Addition Pattern or Vice Versa?

Co-reporter:Natalia B. Shustova ; Yu-Sheng Chen ; Mary A. Mackey ; Curtis E. Coumbe ; J. Paige Phillips ; Steven Stevenson ; Alexey A. Popov ; Olga V. Boltalina

Journal of the American Chemical Society 2009 Volume 131(Issue 48) pp:17630-17637

Publication Date(Web):November 12, 2009

DOI:10.1021/ja9069216

The compounds Sc3N@(C80-Ih(7))(CF3)14 (1) and Sc3N@(C80-Ih(7))(CF3)16 (2) were prepared by heating Sc3N@C80-Ih(7) and Ag(CF3CO2) to 350 °C in a sealed tube. The structures of 1 and 2 were determined by single-crystal X-ray diffraction. They are the first X-ray structures of any endohedral metallofullerene with more than four cage C(sp3) atoms. The structures exhibit several unprecedented features for metallic nitride fullerenes, including multiple cage sp3 triple-hexagon junctions (four on 1 and eight on 2), no cage disorder and little (2) or no (1) endohedral atom disorder, high-precision (C−C esd’s are 0.005 Å for 1 and 0.002 Å for 2), an isolated aromatic C(sp2)6 hexagon on 2, and two negatively charged isolated aromatic C(sp2)5− pentagons on 2 that are bonded to one of the Sc atoms. DFT calculations are in excellent agreement with the two Sc3N conformations observed for 2 (ΔE(calc) = 0.36 kJ mol−1; ΔE(exp) = 0.26(2) kJ mol−1).

X-ray structure and DFT study of C1-C60(CF3)12. A high-energy, kinetically-stable isomer prepared at 500 °C

Co-reporter:Ivan E. Kareev, Natalia B. Shustova, Dmitry V. Peryshkov, Sergey F. Lebedkin, Susie M. Miller, Oren P. Anderson, Alexey A. Popov, Olga V. Boltalina and Steven H. Strauss

Chemical Communications 2007 (Issue 16) pp:1650-1652

Publication Date(Web):19 Mar 2007

DOI:10.1039/B617489B

The title compound, prepared from C60 and CF3I at 500 °C, exhibits an unusual fullerene(X)12 addition pattern that is 40 kJ mol−1 less stable than the previously reported C60(CF3)12 isomer.

Synthesis and structures of poly(perfluoroethyl)[60]fullerenes: 1,7,16,36,46,49-C60(C2F5)6 and 1,6,11,18,24,27,32,35-C60(C2F5)8

Co-reporter:Ivan E. Kareev, Igor V. Kuvychko, Sergei F. Lebedkin, Susie M. Miller, Oren P. Anderson, Steven H. Strauss and Olga V. Boltalina

Chemical Communications 2006 (Issue 3) pp:308-310

Publication Date(Web):21 Nov 2005

DOI:10.1039/B513477C

The high-temperature reaction of C60 and C2F5I produced poly(perfluoroethyl)fullerenes with unprecedented addition patterns.

Reaction of C60 with KMnF4: Isolation and characterization of a new isomer of C60F8 and re-evaluation of the structures of C60F7(CF3) and the known isomer of C60F8

Co-reporter:Alexey A. Goryunkov, Ivan E. Kareev, Ilya N. Ioffe, Alexey A. Popov, Igor V. Kuvychko, Vitaliy Y. Markov, Ilya V. Goldt, Anna S. Pimenova, Mihail G. Serov, Stanislav M. Avdoshenko, Pavel A. Khavrel, Lev N. Sidorov, Sergey F. Lebedkin, Zoran Mazej, Boris Žemva, Steven H. Strauss, Olga V. Boltalina

Journal of Fluorine Chemistry 2006 Volume 127(Issue 10) pp:1423-1435

Publication Date(Web):October 2006

DOI:10.1016/j.jfluchem.2006.06.016

The volatile fluorofullerene products of high-temperature reactions of C60 with the ternary manganese(III, IV) fluorides KMnF4, KMnF5, A2MnF6 (A+ = Li+, K+, Cs+), and K3MnF6 were monitored as a function of reaction temperature, reaction time, and stoichiometric ratio by in situ Knudsen-cell mass spectrometry. When combined with fluorofullerene product ratios from larger-scale (bulk) screening reactions with the same reagents, an optimized set of conditions was found that yielded the greatest amount of C60F8 (KMnF4/C60 mol ratio 28–30, 470 °C, 4–5 h). Two isomers of C60F8 were purified by HPLC, one of which has not been previously reported. Quantum chemical calculations at the DFT level combined with 1D and 2D 19F NMR, FTIR, and FT-Raman spectroscopy indicate that the C60F8 isomer previously reported to be 1,2,3,8,9,12,15,16-C60F8 is actually 1,2,3,6,9,12,15,18-C60F8, making it the first high-temperature fluorofullerene with non-contiguous fluorine atoms. The new isomer, which was found to be 1,2,7,8,9,12,13,14-C60F8, is predicted to be 5.5 kJ mol−1 more stable than 1,2,3,6,9,12,15,18-C60F8 at the DFT level. In addition, new DFT calculations and spectroscopic data indicate that the compound previously isolated from the high-temperature reaction of C60 and K2PtF6 and reported to be 16-CF3-1,2,3,8,9,12,15-C60F7 is actually 18-CF3-1,2,3,6,8,12,15-C60F7.Two isomers of C60F8 were prepared by fluorination of C60 with KMnF4 at high temperature. Their structures, and that of the related compound C60F7(CF3) have been elucidated using a combination of spectroscopic and computational results.

Tetrabutylammonium salt of the B24F224− anion. Two B12F112− icosahedra linked by a 2c–2e BB bond and surrounded by a sheath of CH· · ·FB hydrogen bonds

Co-reporter:Alexey A. Popov;Susie M. Miller;Oren P. Anderson;Konstantin A. Solntsev;Yoshihiro Kobayashi;Sergei V. Ivanov

Heteroatom Chemistry 2006 Volume 17(Issue 3) pp:181-187

Publication Date(Web):10 APR 2006

DOI:10.1002/hc.20220

The B₂₄F₂₂⁴⁻ anion, which was formed as a minor by-product when the B₁₂H₁₂²⁻ anion was treated with F₂ in liquid HF, has been isolated as its N(n-Bu)₄⁺ salt and characterized by ¹⁰B, ¹¹B, and ¹⁹F NMR spectroscopy, electrospray mass spectrometry, cyclic voltammetry, single-crystal X-ray diffraction, and calculations at the DFT level of theory. The B₂₄F₂₂⁴⁻ anion has idealized D₅ symmetry and consists of two B₁₂F₁₁²⁻ icosahedra linked by a 2c–2e boron–boron single bond with a BB distance of 1.725(4) Å. In the solid state, the anion interacts with eight N(n-Bu)₄⁺ cations via a network of 34 CH···FB hydrogen bonds with H· · ·F distances that range from 2.26 to 2.55 Å. These hydrogen bonds were successfully modeled by DFT calculations, which showed that the hydrogen bonds probably have a measurable, albeit subtle, effect on the structure of the B₂₄F₂₂⁴⁻. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:181–187, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20220

Synthesis, Characterization, and Theoretical Study of Stable Isomers of C70(CF3)n (n = 2, 4, 6, 8, 10)

Co-reporter:Eugenii I. Dorozhkin;Daria V. Ignat'eva;Nadezhda B. Tamm Dr.;Alexey A. Goryunkov Dr.;Pavel A. Khavrel;Ilya N. Ioffe Dr.;Alexey A. Popov Dr.;Igor V. Kuvychko;Alexey V. Streletskiy Dr.;Vitaliy Y. Markov Dr.;Johann Spl Dr. ;Olga V. Boltalina

Chemistry - A European Journal 2006 Volume 12(Issue 14) pp:

Publication Date(Web):21 MAR 2006

DOI:10.1002/chem.200501346

Reaction of C₇₀ with ten equivalents of silver(I) trifluoroacetate at 320–340 °C followed by fractional sublimation at 420–540 °C and HPLC processing led to the isolation of a single abundant isomer of C₇₀(CF₃)_n for n = 2, 4, 6, and 10, and two abundant isomers of C₇₀(CF₃)₈. These six compounds were characterized by using matrix-assisted laser desorption ionization (MALDI) mass spectrometry, 2D-COSY and/or 1D ¹⁹F NMR spectroscopy, and quantum-chemical calculations at the density functional theory (DFT) level. Some were also characterized by Raman spectroscopy. The addition patterns for the isolated compounds were unambiguously found to be C₁-7,24-C₇₀(CF₃)₂, C₁-7,24,44,47-C₇₀(CF₃)₄, C₂-1,4,11,19,31,41-C₇₀(CF₃)₆, C_s-1,4,11,19,31,41,51,64-C₇₀(CF₃)₈, C₂-1,4,11,19,31,41,51,60-C₇₀(CF₃)₈, and C₁-1,4,10,19,25,41,49,60,66,69-C₇₀(CF₃)₁₀ (IUPAC numbering). Except for the last compound, which is identical to the recently reported, crystallographically characterized C₇₀(CF₃)₁₀ derivative prepared by a different synthetic route, these compounds have not previously been shown to have the indicated addition patterns. The largest relative yield under an optimized set of reaction conditions was for the C_s isomer of C₇₀(CF₃)₈ (ca. 30 mol % of the sublimed mixture of products based on HPLC integration). The results demonstrate that thermally stable C₇₀(CF₃)_n isomers tend to have their CF₃ groups arranged on isolated para-C₆(CF₃)₂ hexagons and/or on a ribbon of edge-sharing meta- and/or para-C₆(CF₃)₂ hexagons. For C_s- and C₂-C₇₀(CF₃)₈ and for C₂-C₇₀(CF₃)₆, the ribbons straddle the C₇₀ equatorial belt; for C₁-C₇₀(CF₃)₄, the para–meta–para ribbon includes three polar hexagons; for C₁-7,24-C₇₀(CF₃)₂, the para-C₆(CF₃)₂ hexagon includes one of the carbon atoms on a C₇₀ polar pentagon. The 10.3–16.2 Hz ⁷J_F,F NMR coupling constants for the end-of-ribbon CF₃ groups, which are always para to their nearest-neighbor CF₃ group, are consistent with through-space Fermi-contact interactions between the fluorine atoms of proximate, rapidly rotating CF₃ groups.

Seven-Minute Synthesis of Pure Cs-C60Cl6 from [60]Fullerene and Iodine Monochloride: First IR, Raman, and Mass Spectra of 99 mol % C60Cl6

Co-reporter:Igor V. Kuvychko;Alexey V. Streletskii Dr.;Alexey A. Popov Dr.;Sotirios G. Kotsiris Dr.;Thomas Drewello Dr. ;Olga V. Boltalina

Chemistry - A European Journal 2005 Volume 11(Issue 18) pp:

Publication Date(Web):8 JUL 2005

DOI:10.1002/chem.200500185

Three previously reported procedures for the synthesis of pure C_s-C₆₀Cl₆ from C₆₀ and ICl dissolved in benzene or 1,2-dichlorobenzene were shown to actually yield complex mixtures of products that contain, at best, 54–80 % C_s-C₆₀Cl₆ based on HPLC integrated intensities. MALDI mass spectrometry was used for the first time to identify other components of the reaction mixtures. An improved synthetic procedure was developed for the synthesis of about 150 mg batches of chlorofullerenes containing 90 % C_s-C₆₀Cl₆ based on HPLC intensities. The optimum reaction time was decreased from several days to seven minutes. Small amounts of the product were purified by HPLC (toluene eluent) to 99 % purity. The pure compound C_s-C₆₀Cl₆ is stable for at least three months as a solvent-free powder at 25 °C. The Raman, far-IR, and MALDI mass spectra of pure C_s-C₆₀Cl₆ are reported for the first time. The Raman and far-IR spectra, the first reported for any C₆₀Cl_n chlorofullerene, were used to carry out a vibrational analysis of C_s-C₆₀Cl₆ at the DFT level of theory.

High-Temperature Synthesis of the Surprisingly Stable C1-C70

Co-reporter:Ivan E. Kareev, Igor V. Kuvychko, Alexey A. Popov, Sergey F. Lebedkin, Susie M. Miller, Oren P. Anderson, Steven H. Strauss,Olga V. Boltalina

Angewandte Chemie International Edition 2005 44(48) pp:7984-7987

Publication Date(Web):

DOI:10.1002/anie.200502419

Chemical tailoring of fullerene acceptors: synthesis, structures and electrochemical properties of perfluoroisopropylfullerenes

Chemical Communications 2011 - vol. 47(Issue 3) pp:NaN877-877

Publication Date(Web):2010/11/09

DOI:10.1039/C0CC03247F

Poly(trifluoromethyl)azulenes: structures and acceptor properties

Co-reporter:Tyler T. Clikeman, Eric V. Bukovsky, Igor V. Kuvychko, Long K. San, Shihu H. M. Deng, Xue-Bin Wang, Yu-Sheng Chen, Steven H. Strauss and Olga V. Boltalina

Chemical Communications 2014 - vol. 50(Issue 47) pp:NaN6266-6266

Publication Date(Web):2014/04/08

DOI:10.1039/C4CC00510D

Fullerene cyanation does not always increase electron affinity: an experimental and theoretical study

Co-reporter:Tyler T. Clikeman, Shihu H. M. Deng, Alexey A. Popov, Xue-Bin Wang, Steven H. Strauss and Olga V. Boltalina

Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 1) pp:NaN556-556

Publication Date(Web):2014/11/07

DOI:10.1039/C4CP04287E

X-ray structure and DFT study of C1-C60(CF3)12. A high-energy, kinetically-stable isomer prepared at 500 °C

Co-reporter:Ivan E. Kareev, Natalia B. Shustova, Dmitry V. Peryshkov, Sergey F. Lebedkin, Susie M. Miller, Oren P. Anderson, Alexey A. Popov, Olga V. Boltalina and Steven H. Strauss

Chemical Communications 2007(Issue 16) pp:NaN1652-1652

Publication Date(Web):2007/03/19

DOI:10.1039/B617489B

The title compound, prepared from C60 and CF3I at 500 °C, exhibits an unusual fullerene(X)12 addition pattern that is 40 kJ mol−1 less stable than the previously reported C60(CF3)12 isomer.

An elusive fulvene 1,7,11,24-C60(CF3)4 and its unusual reactivity

Co-reporter:James B. Whitaker, Igor V. Kuvychko, Natalia B. Shustova, Yu-Sheng Chen, Steven H. Strauss and Olga V. Boltalina

Chemical Communications 2014 - vol. 50(Issue 10) pp:NaN1208-1208

Publication Date(Web):2013/11/22

DOI:10.1039/C3CC47899H

Dynamic HPLC study of C70 chlorination reveals a surprisingly selective synthesis of C70Cl8

Co-reporter:Igor V. Kuvychko, Alexey A. Popov, Alexey V. Streletskii, Leanne C. Nye, Thomas Drewello, Steven H. Strauss and Olga V. Boltalina

Chemical Communications 2010 - vol. 46(Issue 43) pp:NaN8206-8206

Publication Date(Web):2010/09/27

DOI:10.1039/C0CC03134H

A faux hawk fullerene with PCBM-like properties

Chemical Science (2010-Present) 2015 - vol. 6(Issue 3) pp:NaN1815-1815