John D. Protasiewicz

Insertion of sodium phosphaethynolate, Na[OCP], into a zirconium–benzyne complex

Co-reporter:Jerod M. Kieser;Robert J. Gilliard, Jr.;Arnold L. Rheingold;Hansjörg Grützmacher

Chemical Communications 2017 vol. 53(Issue 37) pp:5110-5112

Publication Date(Web):2017/05/04

DOI:10.1039/C7CC01482A

Reaction of the zirconium–benzyne complex [Cp2Zr(PMe3)(C6H4)] with sodium phosphaethynolate, Na[OCP], affords a zircono-phosphaalkene complex. Notably, unlike reactions of other transition metal complexes with Na[OCP] that yield the products of simple salt metathesis, this transformation represents novel Na[OCP] insertion chemistry and formation of an unusual solid state coordination polymer. The polymer is disrupted upon addition of Me3SiCl to afford a silyl-capped dimer that retains the zirconophosphaalkene functionality. Protonation of either form of zirconophosphaalkenes results in the formation of benzoylphosphine, PhC(O)PH2.

Synthesis of P2C2O2 and P2CO via NHC-mediated coupling of the phosphaethynolate anion

Co-reporter:Robert J. Gilliard, Jr.;Riccardo Suter;Erik Schrader;Zoltán Benkő;Arnold L. Rheingold;Hansjörg Grützmacher

Chemical Communications 2017 vol. 53(Issue 91) pp:12325-12328

Publication Date(Web):2017/11/14

DOI:10.1039/C7CC07654A

The reaction of the chloroimidazolium chloride salt, [NHC-Cl][Cl], NHC = C{N(2,6-iPr2C6H3)CH}2 (1) with two equivalents of sodium phosphaethynolate, Na[OCP]·(dioxane)2.5, results in the formation of NHC-{cyclo-(CO)-P2-C(O)} (2) and NHC-P2-C(O)-NHC (3). Notably, in the presence of free NHC ligand, compound 2 converts to compound 3via extrusion of CO at elevated temperatures. The nature of the bonding in these complexes was probed computationally and spectroscopically.

Tungsten pentacarbonyl complexes of 1,3-benzoxaphospholes

Co-reporter:Alexandra B. Grimm, Sloane Evariste, Arnold L. Rheingold, Curtis E. Moore, John D. Protasiewicz

Journal of Organometallic Chemistry 2017 Volume 851(Volume 851) pp:

Publication Date(Web):15 November 2017

DOI:10.1016/j.jorganchem.2017.08.021

•The synthesis and characterization of a series of air-stable pentacarbonyl-tungsten coordinated 1,3-BOPs have been described.•All [W(CO)5(2-Ar-BOP)] complexes were authenticated by single crystal X-ray diffraction studies.•The optical properties of the Ar-BOPs are strongly influenced after coordination of the P-atom by the [W(CO)5] fragment.2-R-1,3-Benzoxaphospholes (R-BOPs) are examples of fluorescent conjugated materials possessing low coordinate phosphorus centers. A series of 2-(p-XC6H4)-BOPs (X = H, Cl, Br, Me, OMe) react with [W(CO)5(NCMe)] to produce the crystalline complexes [W(CO)5(2-Ar-BOP)] (2a-e). All complexes were characterized by NMR spectroscopy and by single crystal X-ray diffraction. The crystal structures all displayed extensive π-stacking of the BOP ligands and gear locking of the CO groups. Addition of the protecting [W(CO)5] group to the BOPs was discovered to significantly diminish fluorescence of the BOP moiety.Download high-res image (116KB)Download full-size image

Synthesis of a Luminescent Azaphosphole

Co-reporter:Shanshan Wu;Arnold L. Rheingold;James A. Golen;Alexra B. Grimm

European Journal of Inorganic Chemistry 2016 Volume 2016( Issue 5) pp:768-773

Publication Date(Web):

DOI:10.1002/ejic.201501279

Abstract

A carbazole-based azaphosphole (compound 3) has been prepared by acid-catalyzed dehydrocyclization of 1-phosphino-9H-carbazole (2) with benzoyl chloride. Unlike other benzazaphospholes having σ²,λ³-multiply bonded phosphorus atoms, compound 3 displays significant fluorescence in solution, as does primary phosphine 2. Compound 3, as well as the materials on route to its synthesis, were characterized by multinuclear NMR, UV/Vis, and fluorescence spectroscopy. The optical data of 2 and 3 are consistent with results of DFT and TDDFT [6-311G+(d,p) CAMB3LYP] calculations. The computed structure of compound 3′ (R = Ph) is also consistent with the experimental X-ray structural determination, which reveals a planar heterocyclic system and slight rotation of the p-tolyl group out of plane with respect to the heterocyclic core.

Development of new hypervalent iodine reagents with improved properties and reactivity by redirecting secondary bonds at iodine center

Co-reporter:Viktor V. Zhdankin, John D. Protasiewicz

Coordination Chemistry Reviews 2014 Volume 275() pp:54-62

Publication Date(Web):1 September 2014

DOI:10.1016/j.ccr.2014.04.007

•Rational design of soluble, thermally stable, and highly reactive hypervalent iodine reagents.•Iodosylbenzene, (tosylimino)iodobenzenes, and iodonium ylides for atom and group transfer reactions.•Homogeneous catalysis achieved by use of soluble reagents.•Secondary bonding can control solubility and reactivity.•Hypervalent iodine atoms as pseudo-transition metal centers.Hypervalent iodine reagents have found wide application in organic synthesis as versatile, efficient, and environmentally sustainable reagents. Particularly important hypervalent iodine reagents used as atom and group transfer reagents include: iodosylbenzene, (PhIO)n, (tosylimino)iodobenzene, (PhINTs)n, and iodonium ylide, PhI = C(CO2CH3)2. Despite the significant interest in these reagents as primary sources of “O”, “NR” and “CR2” units in transition metal catalyzed processes, their practical application is hampered. In particular, their tightly aggregated and polymeric structures in the solid state render these polyvalent iodine species insoluble in all nonreactive media and prevent their use in chemical reactions under homogenous conditions, which can be undesirable for many synthetic and mechanistic studies. In this review we describe our work on the rational design and development of new soluble, thermally stable, and highly reactive hypervalent iodine reagents based on structural modifications that lead to redirection of secondary bonding from intermolecular to intramolecular modes. Specifically, the introduction of a coordinating donor in the ortho-position of the phenyliodine (III) moiety leads to a significant improvement of solubility of a hypervalent iodine reagent. Based on this approach, we have developed a series of new hypervalent iodine reagents, which can be used as selective oxidants, nitrene or carbene precursors, and atom transfer reagents. Specific examples of these new reagents are represented by iodosylarenes and iminophenyliodanes bearing tert-butylsulfonyl group in the ortho-position of the phenyl ring and by the ortho-alkoxy substituted iodonium imides and ylides. These new pseudocyclic (and cyclic) reagents have excellent solubility in organic solvents and can be used as efficient reagents for catalytic formation of new CO, CN and CC bonds, as well as to enable the generation and detection of highly reactive metal species involved in catalysis and biomimetic reactions.

Luminescent materials containing multiple benzoxaphosphole units

Co-reporter:Shanshan Wu, Arnold L. Rheingold and John D. Protasiewicz

Chemical Communications 2014 vol. 50(Issue 75) pp:11036-11038

Publication Date(Web):07 Aug 2014

DOI:10.1039/C4CC05259E

A series of bisbenzoxaphospholes and a trisbenzoxaphosphole have been prepared and characterized. These extended π-conjugated heterocyclic phosphaalkenes display significant fluorescence in solution having quantum yields between 0.12 and 0.85. The solid state structure of a bisbenzoxaphosphole reveals evidence for extended conjugation, as do DFT calculations.

Phosphoryl-Rich Flame-Retardant Ions (FRIONs): Towards Safer Lithium-Ion Batteries

Co-reporter:Michael F. Rectenwald;Joshua R. Gaffen; Arnold L. Rheingold;Dr. Alexer B. Morgan; John D. Protasiewicz

Angewandte Chemie 2014 Volume 126( Issue 16) pp:4257-4260

Publication Date(Web):

DOI:10.1002/ange.201310867

Abstract

The functionalized catecholate, tetraethyl (2,3-dihydroxy-1,4-phenylene)bis(phosphonate) (H₂-DPC), has been used to prepare a series of lithium salts Li[B(DPC)(oxalato)], Li[B(DPC)₂], Li[B(DPC)F₂], and Li[P(DPC)₃]. The phosphoryl-rich character of these anions was designed to impart flame-retardant properties for their use as potential flame-retardant ions (FRIONs), additives, or replacements for other lithium salts for safer lithium-ion batteries. The new materials were fully characterized, and the single-crystal structures of Li[B(DPC)(oxalato)] and Li[P(DPC)₃] have been determined. Thermogravimetric analysis of the four lithium salts show that they are thermally stable up to around 200 °C. Pyrolysis combustion flow calorimetry reveals that these salts produce high char yields upon combustion.

Phosphoryl-Rich Flame-Retardant Ions (FRIONs): Towards Safer Lithium-Ion Batteries

Co-reporter:Michael F. Rectenwald;Joshua R. Gaffen; Arnold L. Rheingold;Dr. Alexer B. Morgan; John D. Protasiewicz

Angewandte Chemie International Edition 2014 Volume 53( Issue 16) pp:4173-4176

Publication Date(Web):

DOI:10.1002/anie.201310867

Abstract

The functionalized catecholate, tetraethyl (2,3-dihydroxy-1,4-phenylene)bis(phosphonate) (H₂-DPC), has been used to prepare a series of lithium salts Li[B(DPC)(oxalato)], Li[B(DPC)₂], Li[B(DPC)F₂], and Li[P(DPC)₃]. The phosphoryl-rich character of these anions was designed to impart flame-retardant properties for their use as potential flame-retardant ions (FRIONs), additives, or replacements for other lithium salts for safer lithium-ion batteries. The new materials were fully characterized, and the single-crystal structures of Li[B(DPC)(oxalato)] and Li[P(DPC)₃] have been determined. Thermogravimetric analysis of the four lithium salts show that they are thermally stable up to around 200 °C. Pyrolysis combustion flow calorimetry reveals that these salts produce high char yields upon combustion.

An unusually unstable ortho-phosphinophenol and its use to prepare benzoxaphospholes having enhanced air-stability

Co-reporter:Shanshan Wu, Nihal Deligonal and John D. Protasiewicz

Dalton Transactions 2013 vol. 42(Issue 41) pp:14866-14874

Publication Date(Web):30 Aug 2013

DOI:10.1039/C3DT51919H

The primary phosphine 3,5-di-tert-butyl-2-phosphinophenol has been prepared and characterized. Oddly, the presence of a sterically demanding tert-butyl group adjacent to the PH2 centre renders the molecule very sensitive to loss of PH3 and formation of 3,5-di-tert-butyl-phenol in chloroform solutions in the presence of air. The process was catalyzed by HCl and dependent on the purity of CDCl3. Despite the instability of 3,5-di-tert-butyl-2-phosphinophenol, this material could be employed to produce a series of luminescent 2-R-4,6-di-tert-butyl-1,3-benzoxaphospholes having greater air stability than corresponding less bulky 2-R-1,3-benzoxaphospholes.

Naphthoxaphospholes as examples of fluorescent phospha-acenes

Co-reporter:Feng Li Laughlin, Arnold L. Rheingold, Nihal Deligonul, Brynna J. Laughlin, Rhett C. Smith, Lee J. Higham and John D. Protasiewicz

Dalton Transactions 2012 vol. 41(Issue 39) pp:12016-12022

Publication Date(Web):17 Aug 2012

DOI:10.1039/C2DT30902E

Seven new fluorescent 2-R-naphtho[2,3-d]oxaphospholes (R-NOPs) (4a–g; R = tBu (a), Ad (b), C6H5 (c), 4-MeC6H4 (d), 4-ClC6H4 (e), 4-BrC6H4 (f), 4-MeOC6H4 (g)), have been synthesized by cyclocondensation reactions of benzimidoyl chlorides with 3-phosphino-2-naphthol (3). The compounds were characterized by multinuclear NMR, UV-vis, and fluorescence spectroscopy. Compounds 4a–d and 4g were characterized by cyclic voltammetry experiments. The solid state structures of compounds 4b and 4d were also determined by single-crystal X-ray diffraction experiments.

Coordination-Like Chemistry of Phosphinidenes by Phosphanes

Co-reporter:John D. Protasiewicz

European Journal of Inorganic Chemistry 2012 Volume 2012( Issue 29) pp:4539-4549

Publication Date(Web):

DOI:10.1002/ejic.201200273

Abstract

This microreview examines chemistry of phosphane adducts of phosphinidenes (phosphanylidene-σ⁴-phosphoranes, RP=PR₃) whose formation or reactions are reminiscent of the coordination chemistry of phosphane ligands in transition metal complexes.

Redox Behavior of 2-Substituted 1,3-Benzoxaphospholes and 2,6-Substituted Benzo[1,2-d:4,5-d′]bisoxaphospholes

Co-reporter:Marlena P. Washington, John L. Payton, M. Cather Simpson, and John D. Protasiewicz

Organometallics 2011 Volume 30(Issue 7) pp:1975-1983

Publication Date(Web):March 10, 2011

DOI:10.1021/om200014f

The electrochemical behavior of a series of 2-substituted 1,3-benzoxaphospholes and 2,6-disubstituted benzo[1,2-d:4,5-d′]bisoxaphospholes has been examined by cyclic voltammetry methods. One-electron reductions near −1.99 V vs SCE in THF (0.1 M [nBu4N][BF4]) are observed for 2-aryl-1,3-benzoxaphospholes, with the exception of compounds where aryl = p-C6H4Br or p-C6H4Cl, which show irreversible reduction processes. 2,6-Dimesityl-benzobisoxaphosphole and 2,6-dixylyl-benzobisoxaphosphole show two reduction waves, with the first wave displaying reversibility (ca. E1/2 ≈ −2.0 V vs SCE). By contrast, 2,6-di-tert-butyl-benzobisoxaphosphole and 2,6-diadamantyl-benzobisoxaphosphole show single reversible reductions near −2.36 V vs SCE. DFT calculations have been conducted in order to give a greater understanding of the electronic factors influencing the electrochemical results.

Phosphorus Can Also Be a “Photocopy”

Co-reporter:Marlena P. Washington ; Vittal B. Gudimetla ; Feng L. Laughlin ; Nihal Deligonul ; Susan He ; John L. Payton ; M. Cather Simpson

Journal of the American Chemical Society 2010 Volume 132(Issue 13) pp:4566-4567

Publication Date(Web):March 17, 2010

DOI:10.1021/ja1009426

The syntheses of benzoxaphospholes and new benzobisoxaphospholes that display blue fluorescence are presented. The latter compounds were accessed by the use of a new precursor, 2,5-diphosphinohydroquinone. The new compounds were fully characterized, including a structural study of 2,6-tert-butylbenzo[1,2-d;4,5-d′]bisoxaphosphole. Quantum yields for photoluminescence were determined for a series of compounds. These materials feature bona fide P═C p−p π bonds suitable for conjugated materials having phosphorus as a participatory atom and can thus “photocopy” the properties of other conjugated organic molecules.

A Hybrid Lithium Oxalate−Phosphinate Salt

Co-reporter:Andrew R. Shaffer, Nihal Deligonul, Daniel A. Scherson, and John D. Protasiewicz

Inorganic Chemistry 2010 Volume 49(Issue 23) pp:10756-10758

Publication Date(Web):November 8, 2010

DOI:10.1021/ic1018532

The novel organophosphorus-containing lithium salt Li(THF)[(C2O4)B(O2PPh2)2] (1; THF = tetrahydrofuran) was synthesized and characterized using a variety of spectroscopic techniques. An X-ray structural analysis on crystals of 1 grown from THF reveals a dimeric structure [Li(THF)(C2O4)B(O2PPh2)2]2·THF, whereby the two units of 1 are bridged via P−O···Li interactions. Compound 1 displays high air and water stability and is also thermally robust, properties needed of electrolytes for their possible use as electrolytes and/or additives in lithium-ion battery applications.

meta-Terphenyl Phosphaalkenes Bearing Electron-Donating and -Accepting Groups

Co-reporter:Vittal B. Gudimetla;Liqing Ma;Marlena P. Washington;John L. Payton;M. Cather Simpson

European Journal of Inorganic Chemistry 2010 Volume 2010( Issue 6) pp:854-865

Publication Date(Web):

DOI:10.1002/ejic.200900870

Abstract

A set of para-substituted meta-terphenyl phosphaalkenes of the form 4-X-2,6-Mes₂C₆H₂P=C(H)C₆H₄-4-X′ (X = H, MeO or NMe₂; X′ = H, CN, or NO₂) have been synthesized to allow systematic studies of the impact of remote X and X′ substituents on the phosphaalkene unit. The new compounds were characterized by ¹H and ³¹P NMR spectroscopy, UV/Vis absorption spectroscopy, single X-ray crystal structures (for four compounds) and by electrochemical studies. The introduction of remote groups (X′) on the less hindered phenyl ring generated more significant effects on the physical properties of the materials than did substituents (X) on the hindered meta-terphenyl rings. These effects were also explored by computational methods in order to assess the influence of substituents on structures and properties. The polarization of these molecules is less than that produced for analogous alkenes, as the phosphaalkenes bear sterically demanding groups that constrain the systems to adopt conformations that are less than ideal for maximum π-conjugation of the central π network

A closer look at the phosphorus–phosphorus double bond lengths in meta-terphenyl substituted diphosphenes

Co-reporter:John D. Protasiewicz, Marlena P. Washington, Vittal B. Gudimetla, John L. Payton, M. Cather Simpson

Inorganica Chimica Acta 2010 Volume 364(Issue 1) pp:39-45

Publication Date(Web):15 December 2010

DOI:10.1016/j.ica.2010.07.018

The single crystal X-ray structure of DmpPPDmp (1, Dmp = 2,6-Mes2C6H3), which was previously reported to have a relatively short PP bond distance of 1.985(2) Å at room temperature, has been reexamined at variable temperatures. Crystallographic analyses of 1 at 100 K allow for resolution of disorder of the two phosphorus atoms (which is unresolvable from room temperature diffraction data), and for determination of a more conventional PP bond length of 2.029(1) Å. Single crystals of the closely related diphosphene DxpPPDxp (2, Dxp = 2,6-(2,6-Me2C6H3)2C6H3) show similar disorder in one of two crystallographically independent molecules in the unit cell. A value of 2.0276(4) Å is found for the non-disordered PP bonds at 100 K for 2. A new diphosphene Ar′PPAr′ (3, Ar′ = 2,6-Mes2-4-OMe–C6H3) has been prepared and its structure has also been examined. The PP bond length for 3 was determined to be 2.0326(9) Å and relatively free of the effects of disorder.Detailed X-ray structural analyses of some diphosphenes of the form Ar′PPAr′ (Ar′ = meta-terphenyl) reveal the phosphorus atoms to be disordered, giving the impression that the P atoms are rattling around in between the two well ordered ligands (as if “in a can”). The disorder, if unresolved, can give rise to erroneous PP bond distances.

Enhancing the solubility for hypervalent ortho-sulfonyl iodine compounds

Co-reporter:Bindu V. Meprathu, John D. Protasiewicz

Tetrahedron 2010 66(31) pp: 5768-5774

Publication Date(Web):

DOI:10.1016/j.tet.2010.04.087

Unusual Phosphorus−Phosphorus Double Bond Contraction upon Mono- and Di-auration of a Diphosphene

Co-reporter:David V. Partyka ; Marlena P. Washington ; Thomas G. Gray ; James B. Updegraff III ; John F. Turner ; II

Journal of the American Chemical Society 2009 Volume 131(Issue 29) pp:10041-10048

Publication Date(Web):July 1, 2009

DOI:10.1021/ja900813v

The diphosphene Mes*P═Mes* (Mes* = 2,4,6-tri-tert-butylphenyl; 1) reacted with 1 or 2 equiv of Au(tht)Cl (tht = tetrahydrothiophene) to produce the stable monoaurated adduct Mes*{AuCl}P═PMes* (2) or diaurated adduct Mes*{AuCl}P═P{AuCl}Mes* (3) respectively. The products were characterized by X-ray crystallography, UV−visible, IR, Raman, and multinuclear NMR spectroscopies, as well as by density functional theory calculations. The crystallographic and Raman spectroscopic data provide physical evidence that the P═P bond grows shorter and increases in strength upon auration; these observations are further examined by DFT calculations for a series of model compounds CH3{AuCl}nP═P{AuCl}n′CH3 1′−3′ (n, n′ = 0 or 1). Compounds 1−3 represent a rare series of crystallographically characterized diphosphenes bearing zero, one, or two AuCl units on each phosphorus atom, allowing for a systematic analysis of the impact of Lewis acids on the phosphorus−phosphorus double bond.

Phosphinidene group-transfer with a phospha-Wittig reagent: a new entry to transition metal phosphorus multiple bonds

Co-reporter:Uriah J. Kilgore, Hongjun Fan, Maren Pink, Eugenijus Urnezius, John D. Protasiewicz and Daniel J. Mindiola

Chemical Communications 2009 (Issue 30) pp:4521-4523

Publication Date(Web):06 Jul 2009

DOI:10.1039/B910410K

The phosphanylidene-σ4-phosphorane reagents Me3PPAr (Ar = 2,4,6-tBu3C6H2 and 2,6-Mes2C6H3) are good delivery vehicles of the terminal phosphinidene moiety, PAr, to early-transition metals composed of zirconium and vanadium.

Improved synthesis of pincer ligand precursor, and synthesis and structural characterization of terphenyl scaffolded S–C–S palladium pincer complex

Co-reporter:Paul M. Schroder, Thomas F. Spilker, Wilson Luu, James B. Updegraff III, Man Lung Kwan, Paul R. Challen, John D. Protasiewicz

Inorganic Chemistry Communications 2009 Volume 12(Issue 12) pp:1171-1174

Publication Date(Web):December 2009

DOI:10.1016/j.inoche.2009.08.036

An easier and more expedient synthesis of 2,6-(BrCH2C6H4)2-4-I-C6H3 (2) is reported. This material allowed easy synthesis of the new pincer ligand precursor 2,6-(4-CH3C6H4SCH2C6H4)2-4-I-C6H3 (3) in 87% yield. Compound 3 reacts with Pd2(dba)3 to give the new palladium pincer complex 4. Compound 4 has been fully characterized, including structural characterization by single crystal X-ray diffraction methods. The results of the crystallographic work on 4 reveal a twisted type pincer complex not unlike related terphenyl pincer complexes.A quicker preparation of terphenyl pincer ligand intermediate has been developed, and used to prepare a new S–C–S pincer ligand precursor. The new S–C–S palladium pincer complex has been prepared from this ligand precursor and structurally characterized.

Latent cationic palladium(II) phosphine carboxylate complexes for norbornene polymerization

Co-reporter:Natesan Thirupathi;Dino Amoroso;Andrew Bell

Journal of Polymer Science Part A: Polymer Chemistry 2009 Volume 47( Issue 1) pp:103-110

Publication Date(Web):

DOI:10.1002/pola.23125

Abstract

The catalytic efficacy of trans-[(R₃P)₂Pd(O₂CR′)(LB)][B(C₆F₅)₄] (1) (LB = Lewis base) and [(R₃P)₂Pd(κ²-O,O-O₂CR′)][B(C₆F₅)₄] (2) for mass polymerization of 5-n-butyl-2-norbornene (Butyl-NB) was investigated. The nature of PR₃ and LB in 1 and 2 are the most critical components influencing catalytic activity/latency for the mass polymerization of Butyl-NB. Further, it was shown that 1 is in general more latent than 2 in mass polymerization of Butyl-NB. 5-n-Decyl-2-norbornene (Decyl-NB) was subjected to solution polymerization in toluene at 63(±3) °C in the presence of several of the aforementioned palladium complexes as catalysts and the polymers obtained were characterized by gel permeation chromatography. Cationic trans-[(R₃P)₂PdMe(MeCN)][B(C₆F₅)₄] [R = Cy (3a), and ⁱPr (3b)] and trans-[(R₃P)₂PdH (MeCN)][B(C₆F₅)₄] [R = Cy (4a), and ⁱPr (4b)], possible products from thermolysis of trans-[(R₃P)₂Pd(O₂CMe)(MeCN)][B(C₆F₅)₄] [R = Cy (1a) and ⁱPr (1g)], as well as trans-[(R₃P)₂Pd(η³-C₃H₅)][B(C₆F₅)₄] [R = Cy (5a), and ⁱPr (5b)], were also examined as catalysts for solution polymerization of Decyl-NB. A maximum activity of 5360 kg/(molPd h) of 2a was achieved at a Decyl-NB/Pd: 26,700 ratio which is slightly better than that achieved with 5a [activity: 5030 kg/(molPd h)] but far less compared with 4a [activity: 6110 kg/(molPd h)]. Polydispersity values indicate a single highly homogeneous character of the active catalyst species. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 103–110, 2009

m-Terphenyl Anchored Palladium Diphosphinite PCP-Pincer Complexes That Promote the Suzuki−Miyaura Reaction Under Mild Conditions

Co-reporter:Mark C. Lipke, Robert A. Woloszynek, Liqing Ma and John D. Protasiewicz

Organometallics 2009 Volume 28(Issue 1) pp:188-196

Publication Date(Web):December 5, 2008

DOI:10.1021/om800626b

Diphosphinite PCP-pincer pro-ligands anchored by a meta-terphenyl backbone were synthesized. These pro-ligands, [2,6-(2-Ph2POC6H4)2C6H3X] (3a X = I, 3b X = Br) and [2,6-(2-iPr2POC6H4)2C6H3X] (4a X = I, 4b X = Br) upon reaction with Pd2(dba)3 yield PCP palladium pincer complexes [2,6-(2-Ph2POC6H4)2C6H3PdX] (5a X = I, 5b X = Br) and [2,6-(2-iPr2POC6H4)2C6H3PdX] (6a X = I, 6b X = Br). The structures of 5a−b and 6a−b were determined by single crystal X-ray diffraction analyses. Complexes 5b and 6b were evaluated for their efficacy in promoting catalytic Suzuki−Miyaura CC coupling reactions. A variety of aryl bromides efficiently underwent CC coupling reactions with p-tolylboronic acid with high yields in the presence of either 5b or 6b. Compound 6b also proved to be a very active pro-catalyst for the coupling of aryl chlorides with p-tolylboronic acid. Excellent to good yields (in some cases greater than 90%) were achieved even with electron rich or sterically hindered aryl chlorides.

Surveying the {AuCl} adducts of bulky phosphines bearing the 2,6-dimesitylphenyl group

Co-reporter:David V. Partyka, Marlena P. Washington, James B. Updegraff III, Xufang Chen, Christopher D. Incarvito, Arnold L. Rheingold, John D. Protasiewicz

Journal of Organometallic Chemistry 2009 694(9–10) pp: 1441-1446

Publication Date(Web):

DOI:10.1016/j.jorganchem.2008.12.051

Synergistic Binding of Both Lewis Acids and Bases to Phosphinidenes

Co-reporter:DavidV. Partyka Dr.;MarlenaP. Washington;JamesB. Updegraff III;RobertA. Woloszynek;JohnD. Protasiewicz

Angewandte Chemie International Edition 2008 Volume 47( Issue 39) pp:7489-7492

Publication Date(Web):

DOI:10.1002/anie.200801741

Synergistic Binding of Both Lewis Acids and Bases to Phosphinidenes

Co-reporter:DavidV. Partyka Dr.;MarlenaP. Washington;JamesB. Updegraff III;RobertA. Woloszynek;JohnD. Protasiewicz

Angewandte Chemie 2008 Volume 120( Issue 39) pp:7599-7602

Publication Date(Web):

DOI:10.1002/ange.200801741

Suzuki and Heck coupling reactions mediated by palladium complexes bearing trans-spanning diphosphines

Co-reporter:Rhett C. Smith, Christina R. Bodner, Meredith J. Earl, Nathaniel C. Sears, Nicholas E. Hill, Lee M. Bishop, Nicholas Sizemore, Dave T. Hehemann, Justin J. Bohn, John D. Protasiewicz

Journal of Organometallic Chemistry 2005 Volume 690(Issue 2) pp:477-481

Publication Date(Web):17 January 2005

DOI:10.1016/j.jorganchem.2004.09.077

Palladium complexes of three trans-spanning diphosphines are examined for effecting C–C coupling reactions. Ten aryl halides of varying electron density were screened in Suzuki coupling reactions with phenylboronic acid and in Heck reactions with styrene. The results are discussed in terms of the unique flexibility and shape of the meta-terphenyl backbone upon which the diphosphine ligand is built.Suzuki and Heck coupling reactions mediated by palladium complexes bearing trans-spanning diphosphinesPalladium complexes of three trans-spanning diphosphines are examined for effecting C–C coupling reactions. Ten aryl halides of varying electron density were screened in Suzuki coupling reactions with phenylboronic acid and in Heck reactions with styrene.

Insertion of sodium phosphaethynolate, Na[OCP], into a zirconium–benzyne complex

Co-reporter:Jerod M. Kieser, Robert J. Gilliard, Jr., Arnold L. Rheingold, Hansjörg Grützmacher and John D. Protasiewicz

Chemical Communications 2017 - vol. 53(Issue 37) pp:NaN5112-5112

Publication Date(Web):2017/04/21

DOI:10.1039/C7CC01482A

Reaction of the zirconium–benzyne complex [Cp2Zr(PMe3)(C6H4)] with sodium phosphaethynolate, Na[OCP], affords a zircono-phosphaalkene complex. Notably, unlike reactions of other transition metal complexes with Na[OCP] that yield the products of simple salt metathesis, this transformation represents novel Na[OCP] insertion chemistry and formation of an unusual solid state coordination polymer. The polymer is disrupted upon addition of Me3SiCl to afford a silyl-capped dimer that retains the zirconophosphaalkene functionality. Protonation of either form of zirconophosphaalkenes results in the formation of benzoylphosphine, PhC(O)PH2.

Phosphinidene group-transfer with a phospha-Wittig reagent: a new entry to transition metal phosphorus multiple bonds

Co-reporter:Uriah J. Kilgore, Hongjun Fan, Maren Pink, Eugenijus Urnezius, John D. Protasiewicz and Daniel J. Mindiola

Chemical Communications 2009(Issue 30) pp:NaN4523-4523

Publication Date(Web):2009/07/06

DOI:10.1039/B910410K

The phosphanylidene-σ4-phosphorane reagents Me3PPAr (Ar = 2,4,6-tBu3C6H2 and 2,6-Mes2C6H3) are good delivery vehicles of the terminal phosphinidene moiety, PAr, to early-transition metals composed of zirconium and vanadium.

Naphthoxaphospholes as examples of fluorescent phospha-acenes

Co-reporter:Feng Li Laughlin, Arnold L. Rheingold, Nihal Deligonul, Brynna J. Laughlin, Rhett C. Smith, Lee J. Higham and John D. Protasiewicz

Dalton Transactions 2012 - vol. 41(Issue 39) pp:NaN12022-12022

Publication Date(Web):2012/08/17

DOI:10.1039/C2DT30902E

Seven new fluorescent 2-R-naphtho[2,3-d]oxaphospholes (R-NOPs) (4a–g; R = tBu (a), Ad (b), C6H5 (c), 4-MeC6H4 (d), 4-ClC6H4 (e), 4-BrC6H4 (f), 4-MeOC6H4 (g)), have been synthesized by cyclocondensation reactions of benzimidoyl chlorides with 3-phosphino-2-naphthol (3). The compounds were characterized by multinuclear NMR, UV-vis, and fluorescence spectroscopy. Compounds 4a–d and 4g were characterized by cyclic voltammetry experiments. The solid state structures of compounds 4b and 4d were also determined by single-crystal X-ray diffraction experiments.

An unusually unstable ortho-phosphinophenol and its use to prepare benzoxaphospholes having enhanced air-stability

Co-reporter:Shanshan Wu, Nihal Deligonal and John D. Protasiewicz

Dalton Transactions 2013 - vol. 42(Issue 41) pp:NaN14874-14874

Publication Date(Web):2013/08/30

DOI:10.1039/C3DT51919H

The primary phosphine 3,5-di-tert-butyl-2-phosphinophenol has been prepared and characterized. Oddly, the presence of a sterically demanding tert-butyl group adjacent to the PH2 centre renders the molecule very sensitive to loss of PH3 and formation of 3,5-di-tert-butyl-phenol in chloroform solutions in the presence of air. The process was catalyzed by HCl and dependent on the purity of CDCl3. Despite the instability of 3,5-di-tert-butyl-2-phosphinophenol, this material could be employed to produce a series of luminescent 2-R-4,6-di-tert-butyl-1,3-benzoxaphospholes having greater air stability than corresponding less bulky 2-R-1,3-benzoxaphospholes.

Luminescent materials containing multiple benzoxaphosphole units

Co-reporter:Shanshan Wu, Arnold L. Rheingold and John D. Protasiewicz

Chemical Communications 2014 - vol. 50(Issue 75) pp:NaN11038-11038

Publication Date(Web):2014/08/07

DOI:10.1039/C4CC05259E

A series of bisbenzoxaphospholes and a trisbenzoxaphosphole have been prepared and characterized. These extended π-conjugated heterocyclic phosphaalkenes display significant fluorescence in solution having quantum yields between 0.12 and 0.85. The solid state structure of a bisbenzoxaphosphole reveals evidence for extended conjugation, as do DFT calculations.