Co-reporter:Richard A. Mole, Stephen Greene, Paul F. Henry, Simon M. Humphrey, Kirrily C. Rule, Tobias Unruh, Gerald F. Weldon, Dehong Yu, John A. Stride, and Paul T. Wood
Inorganic Chemistry July 17, 2017 Volume 56(Issue 14) pp:7851-7851
Publication Date(Web):June 22, 2017
DOI:10.1021/acs.inorgchem.7b00597
Kagomé lattice types have been of intense interest as idealized examples of extended frustrated spin systems. Here we demonstrate how the use of neutron diffraction and inelastic neutron scattering coupled with spin wave theory calculations can be used to elucidate the complex magnetic interactions of extended spin networks. We show that the magnetic properties of the coordination polymer Mn3(1,2,4-(O2C)3C6H3)2, a highly distorted kagomé lattice, have been erroneously characterized as a canted antiferromagnet in previous works. Our results demonstrate that, although the magnetic structure is ferrimagnetic, with a net magnetic moment, frustration persists in the system. We conclude by showing that the conventions of the Goodenough–Kanamori rules, which are often applied to similar magnetic exchange interactions, are not relevant in this case.
Co-reporter:Nolan W. Waggoner, Beau Saccoccia, Ilich A. Ibarra, Vincent M. Lynch, Paul T. Wood, and Simon M. Humphrey
Inorganic Chemistry 2014 Volume 53(Issue 24) pp:12674-12676
Publication Date(Web):December 3, 2014
DOI:10.1021/ic5023642
Two new isostructural phosphine coordination materials, Ln-PCM-21 (Ln = Pr, Nd), have been obtained using a tris(p-carboxylated) methyltriphenylphosphonium ligand that is formally dianionic when triply deprotonated, allowing access to materials based on uncommon metal-to-ligand ratios. The polymers of the formula [Ln3(mptbc)4]X·solv (X = Cl–, NO3–) are cationic and contain unusual, linear oxo-bridged [Ln3]9+ clusters. Magnetic susceptibility data for both the Pr and Nd analogues has been compared to models based on three contrasting approaches.
Co-reporter:Richard A. Mole ; John A. Stride ; Paul F. Henry ; Markus Hoelzel ; Anatoliy Senyshyn ; Antonio Alberola ; Carlos J. Gómez Garcia ; Paul R. Raithby ▽
Inorganic Chemistry 2011 Volume 50(Issue 6) pp:2246-2251
Publication Date(Web):February 4, 2011
DOI:10.1021/ic101897a
We report the magnetic structure of two of the mag-netically ordered phases of Co3(OH)2(C4O4)2·3H2O, a coordination polymer that consists of a triangular framework decorated with anisotropic Co(II) ions. The combination of neutron diffraction experiments and magnetic susceptibility data allows us to identify one phase as displaying spin idle behavior, where only a fraction of the moments order at intermediate temperatures, while at the lowest temperatures the system orders fully. This novel magnetic behavior is discussed within the framework of a simple Hamiltonian and representational analysis and rationalizes this multiphase behavior by considering the combination of frustration and anisotropy.
Co-reporter:Dr. John Bacsa;Dr. Robert J. Less;Helen E. Skelton;Zlatko Soracevic;Dr. Alexer Steiner;Thomas C. Wilson;Dr. Paul T. Wood; Dominic S. Wright
Angewandte Chemie International Edition 2011 Volume 50( Issue 36) pp:8279-8282
Publication Date(Web):
DOI:10.1002/anie.201102783
Co-reporter:Simon M. Humphrey, Richard A. Mole, Richard I. Thompson and Paul T. Wood
Inorganic Chemistry 2010 Volume 49(Issue 7) pp:3441-3448
Publication Date(Web):March 5, 2010
DOI:10.1021/ic902527e
The hexaanion of mellitic acid, mel = (C6(CO2)6)6−, links metal ions into extensively connected magnetic coordination polymers. Reaction of alkali metal mellitate salts, M6(mel) (M = K, Rb), with M′Cl2 precursors (M′ = Mn, Co, Ni) under mild (473 K) hydrothermal conditions yields an extensive family of isostructural 3-dimensional mixed alkali metal/transition metal polymers of general formula M2[M′2(mel)(OH2)2] (M/M′ = K/Mn (1a); K/Co (1b); K/Ni (1c); Rb/Mn (2a); Rb/Co (2b); Rb/Ni (2c)). These materials incorporate distorted 2-dimensional magnetic hexagonal nets with a honeycomb topology that are exclusively based on metal-carboxylate-metal bridging interactions. A further isostructural alkali metal-free Co2+ material with NH4+ cations, (NH4)2[Co2(mel)(OH2)2] (3), produced by reaction of H6mel with [Co(NH3)6]Cl3 is also presented. The magnetic susceptibility data for 1a−c, 2a−c, and 3 are presented. The susceptibility data for the Mn(II)- and Ni(II)-containing phases have been analyzed using a simple Mean Field Theory approach, and have been modeled using a high temperature series expansion. The comparative magnetism of the Co(II) phases is also presented, and is more complicated because of significant spin−orbit coupling effects.
Co-reporter:Richard A. Mole, Stephen P. Cottrell, John A. Stride, Paul T. Wood
Inorganica Chimica Acta 2008 Volume 361(12–13) pp:3718-3722
Publication Date(Web):1 September 2008
DOI:10.1016/j.ica.2008.03.108
Muon spin relaxation has been used to study the magnetic phase transition and spin dynamics above Tc in Mn2(OH)2(C4O4). These studies confirm previous findings of a transition to long range order, providing a more accurate determination of Tc = 12.5 K as well as indicating short range order at temperatures above the phase transition. The muon measurements are insensitive to the presence of a small quantity of manganese carbonate in the sample that tend to dominate bulk magnetic susceptibility experiments.Muon spin relaxation has been used to probe the paramagnetic to antiferromagnetic phase transition in manganese hydroxy squarate, Mn2(OH)2(C4O4). This confirms that the ordering temperature is 12.5 K and shows that there is significant short range order well above Tc.
Co-reporter:J. W. Yoon;S. H. Jhung;Y. K. Hwang;S. M. Humphrey;P. T. Wood;J.-S. Chang
Advanced Materials 2007 Volume 19(Issue 14) pp:1830-1834
Publication Date(Web):14 JUN 2007
DOI:10.1002/adma.200601983
As a size-selective molecular sieve, the coordination polymer formed from cobalt and pyridine-2,4-dicarboxylic acid (CUK-1, see figure) shows unprecedented selectivity for O2 and preferential selectivity for CO2 over CH4. The present sorption results encourage the development of new adsorbent materials that may find use in the production of high-purity gas products. This work demonstrates that CUK-1 can be utilized, for the first time, in the separation of light gases via gas chromatography.
Co-reporter:Simon M. Humphrey Dr.;Jong-San Chang Dr.;Sung Hwa Jhung Dr.;Ji Woong Yoon Dr.;Paul T. Wood Dr.
Angewandte Chemie International Edition 2007 Volume 46(Issue 1‐2) pp:
Publication Date(Web):28 NOV 2006
DOI:10.1002/anie.200601627
Resilient hosts: The porous coordination solids CUK-1 (see structure; Co purple, C gray, N blue, O red/pink) and CUK-2 are synthesized from unsymmetrical ligands and CoII ions. Even after the removal of co-crystallized guests, the host frameworks are exceptionally stable. CUK-1 shows a high capacity for H2 adsorption and is one of very few materials capable of separating N2 from O2.
Co-reporter:Simon M. Humphrey Dr.;Jong-San Chang Dr.;Sung Hwa Jhung Dr.;Ji Woong Yoon Dr.;Paul T. Wood Dr.
Angewandte Chemie 2007 Volume 119(Issue 1‐2) pp:
Publication Date(Web):28 NOV 2006
DOI:10.1002/ange.200601627
Unverwüstliche Wirte: Die porösen Koordinationsfestkörper CUK-1 (siehe Struktur; Co violett, C grau, N blau, O rot/rosa) und CUK-2 wurden aus unsymmetrischen Liganden und CoII-Ionen hergestellt. Auch ohne die mitkristallisierten Gäste sind die Wirtgerüste außergewöhnlich stabil. CUK-1 hat eine hohe H2-Adsorptionskapazität und ist eines der wenigen Materialien, die N2 von O2 trennen können.
Co-reporter:Simon M. Humphrey, Antonio Alberola, Carlos J. Gómez García and Paul T. Wood
Chemical Communications 2006 (Issue 15) pp:1607-1609
Publication Date(Web):08 Mar 2006
DOI:10.1039/B600347H
Reaction of Co(II) chloride with the sodium salt of 2-mercaptonicotinic acid in water at 200 °C results in the formation of Co4(2-mna)4(H2O), which orders as a canted antiferromagnet at 68 K.
Co-reporter:Dale Cave, Fiona C. Coomer, Eduardo Molinos, Hans-Henning Klauss,Paul T. Wood
Angewandte Chemie International Edition 2006 45(5) pp:803-806
Publication Date(Web):
DOI:10.1002/anie.200502847
Co-reporter:Dale Cave Dr.;Fiona C. Coomer;Eduardo Molinos;Hans-Henning Klauss Dr. Dr.
Angewandte Chemie 2006 Volume 118(Issue 5) pp:
Publication Date(Web):21 DEC 2005
DOI:10.1002/ange.200502847
Eine neue Seite wird aufgeschlagen: In den titelgebenden Eisenphosphonaten sind Dreiecke und Sechsecke zu einem Ahornblatt-Gitter kondensiert (siehe Polyederdarstellung; grün Fe, violett P). Bei diesem Gitter handelt es sich um eine neue Art eines topologisch frustrierten antiferromagnetischen Netzwerks. Solche frustrierten Materialien zeigen oft exotische Formen des magnetischen Verhaltens.
Co-reporter:Simon M. Humphrey, Richard A. Mole, Jeremy M. Rawson and Paul T. Wood
Dalton Transactions 2004 (Issue 11) pp:1670-1678
Publication Date(Web):06 May 2004
DOI:10.1039/B401887G
The hydrothermal reaction of thiosalicylic acid, (C6H4(CO2H)(SH)-1,2) with manganese(III) acetate leads to formation of the coordination solid [Mn5((C6H4(CO2)(S)-1,2)2)4(μ3-OH)2]
(1)
via a redox reaction, where resulting manganese(II) centres are coordinated by oxygen donor atoms and S–S disulfide bridge formation is simultaneously observed. Reaction of the same ligand under similar conditions with zinc(II) chloride yields the layered coordination solid [Zn(C6H4(CO2)(S)-1,2)]
(2). Hydrothermal treatment of manganese(III) acetate with 2-mercaptonicotinic acid, (NC5H3(SH)(CO2H)-2,3) was found to produce the 1-dimensional chain structure [Mn2((NC5H3(S)(CO2)-2,3)2)2(OH2)4]·4H2O (3) which also exhibits disulfide bridge formation and oxygen-only metal interactions. Compound 3 has been studied by thermogravimetric analysis and indicates sequential loss of lattice and coordinated water, prior to more comprehensive ligand fragmentation at elevated temperatures. The magnetic behaviour of 1 and 3 has been investigated and both exhibit antiferromagnetic interactions. The magnetic behaviour of 1 has been modelled as two corner-sharing isosceles triangles whilst 3 has been modelled as a 1-dimensional chain.
Co-reporter:Siegfried O. H. Gutschke Dr.;Daniel J. Price Dr.;Annie K. Powell Dr.
Angewandte Chemie 2001 Volume 113(Issue 10) pp:
Publication Date(Web):15 MAY 2001
DOI:10.1002/1521-3757(20010518)113:10<1974::AID-ANGE1974>3.0.CO;2-7
Die drei klassischen Koordinationsumgebungen liegen in [Co2(OH){1,2,3-(O2C)3C6H3}(H2O)]⋅H2O vor: Oktaedrisch (schraffiert) und tetraedrisch koordinierte Co-Zentren (punktiert) wechseln sich ab, an den verbrückenden OH-Gruppen befinden sich trigonal-bipyramidal koordinierte Co-Zentren (gestreift). Diese Verbindung wurde durch Hydrothermalsynthese aus CoCl2, NaOH und Benzol-1,2,3-tricarbonsäure erhalten; durch leichte Variation der Bedingungen entstand eine Verbindung ähnlicher Zusammensetzung, aber mit ganz andererer Struktur. Beide Verbindungen sind Beispiele für die seltene Δ-Kettentopologie und zeigen ungewöhnliche magnetische Eigenschaften.
