Towards the design of linear homo-trinuclear metal complexes based on a new phenol-functionalised diazamesocyclic ligand: Structural analysis and magnetism

The formation of two novel phenoxo-bridged linear trimetallic Cu I I and Ni I I complexes, [Cu 3 (μ-L) 2 ](CH 3 OH) 2 (ClO 4 ) 2 (1) and [Ni 3 (μ-L) 2 (CH 3 OH) 2 ](ClO 4 ) 2 (2), with a new diazamesocyclic ligand functionalised by additional phenol donor pendants (H 2 L = N,N'- bis(2-hydroxybenzyl)-1,4-diazacycloheptane), has been achieved and both complexes have been characterised by IR spectroscopy, elemental analyses, conductivity measurements, thermal analyses and UV/Vis techniques. Single-crystal X-ray diffraction analyses revealed that both 1 and 2 have the similar phenoxo-bridged linear trinuclear cores. For 1, two terminal and the central Cu I I ion are in square-planar environments with the adjacent intramolecular Cu...Cu separation of 2.9376(9) A. For 2, however, two terminal Ni I I ions are in square-planar environments and the central Ni I I ion assumes an octahedral geometry by axial coordination of two methanol ligands, the adjacent intramolecular Ni...Ni distance being 3.007(3) A. In both cases, the 1,4-diazacycloheptane (DACH) ring adopts the normal boat configuration. The magnetic properties of complexes 1 and 2 have been investigated by variable-temperature magnetic susceptibility measurements in the solid state. Complex 1 displays a very strong antiferromagnetic coupling interaction between the neighbouring μ-phenoxo Cu I I centres with a J parameter of -314 cm - 1 and the magneto-structural correlation for such complexes is discussed in detail. For complex 2, the result indicates that both terminal Ni I I ions are diamagnetic and the central Ni I I shows typical paramagnetic behaviour. The presence of zero-field splitting for Ni I I with a D parameter of 11 cm - 1 , being active at low temperature, is further corroborated by the magnetisation measurement at 2 K. Additionally, the interesting ESR spectra of 1 at different temperatures (from 298 K to 8 K) were investigated and interpreted.

[1]  X. Bu,et al.  Ligand design for alkali-metal-templated self-assembly of unique high-nuclearity CuII aggregates with diverse coordination cage units: crystal structures and properties. , 2004, Chemistry.

[2]  Robert K Szilagyi,et al.  Electronic structures of metal sites in proteins and models: contributions to function in blue copper proteins. , 2004, Chemical reviews.

[3]  A. Spek,et al.  Two pyrazolato-bridged, linear trinuclear Cu(II) complexes. Crystal structures and magnetic properties , 2003 .

[4]  R. Sessoli,et al.  Quantum tunneling of magnetization and related phenomena in molecular materials. , 2003, Angewandte Chemie.

[5]  X. Bu,et al.  Synthesis, crystal structure and properties of the CuII complex of a tetradentate imidazole-functionalized diazamesocyclic ligand, 1,4-bis(N-1-methylimidazol-2-yl-methyl)-1,4-diazacycloheptane , 2002 .

[6]  K. Nakajima,et al.  Antiferromagnetism induced by successive protonation of terminal phenol groups of a bis(μ-phenoxide)-bridged dicopper(II,II) complex , 2002 .

[7]  X. Bu,et al.  A novel oxalato-bridged dinuclear copper(II) complex with diazamesocyclic terminal ligand: crystal structure, spectroscopy and magnetism , 2002 .

[8]  X. Bu,et al.  Structural and first magnetic characterization of unique mono-μ-chloro bridged dinuclear CuII complexes with heterocycle-functionalized diazamesocyclic ligands , 2002 .

[9]  X. Bu,et al.  Structural and spectral investigation on the Co II complexes with 1,4-diazacycloheptane (DACH) functionalized by heterocyclic pendants , 2002 .

[10]  R. Boča,et al.  Synthesis and Structural Characterization of Trinuclear CuII−Pyrazolato Complexes Containing μ3-OH, μ3-O, and μ3-Cl Ligands. Magnetic Susceptibility Study of [PPN]2[(μ3-O)Cu3(μ-pz)3Cl3] , 2002 .

[11]  J. Reedijk,et al.  X-ray crystal structures, spectroscopic and magnetic measurements of dinuclear alkoxo-bridged copper(II) compounds with substituted bis(2-benzimidazolyl)alkane ligands. First X-ray structure of a copper(II) dinuclear propoxo-bridged compound , 2002 .

[12]  X. Bu,et al.  Ferromagnetic coupling in a unique Cu(II) metallacyclophane with functionalized diazamesocyclic ligands formed by Cu(II)-directed self-assembly: magneto-structural correlations for dichloro-bridged Cu(II) dinuclear complexes , 2002 .

[13]  X. Bu,et al.  Three-dimensional frameworks built from hydrogen bonds and π–π stacking interactions: structural and spectral study on Co(II) complexes of 1,5-diazacyclooctane (DACO) functionalized by heterocyclic pendants , 2001 .

[14]  X. Bu,et al.  Isolation of a thermodynamically unfavorable [Ni(DACO)2]2+ complex and its isomer: syntheses, characterization, crystal structures and theoretical study (DACO=1,5-diazacyclooctane) , 2001 .

[15]  X. Bu,et al.  Varying coordination modes and magnetic properties of copper(II) complexes with diazamesocyclic ligands by altering additional donor pendants on 1,5-diazacyclooctane. , 2000, Inorganic chemistry.

[16]  J. Cano,et al.  Countercomplementarity and strong ferromagnetic coupling in a linear mixed mu-acetato, mu-hydroxo trinuclear copper(II) complex. Synthesis, structure, magnetic properties, EPR, and theoretical studies. , 2000, Inorganic chemistry.

[17]  J. Seco,et al.  Synthesis, spectroscopic, magnetic and EPR studies and crystal structure of di-μ-(N-phenyl-N-methoxy-2-pyridinamine)bis[(NN) copper(II)]perchlorate, NN=2,2′-bipyridyl or 1,10-phenanthroline , 2000 .

[18]  J. G. Haasnoot,et al.  Trinuclear N,N-bridged copper(II) complexes involving a Cu3OH core: [Cu3(mu 3-OH)L3A(H2O)2]A.(H2O)x (L = 3-acetylamino-1,2,4-triazolate; a = CF3SO3, NO3, ClO4; x = 0, 2) synthesis, X-ray structures, spectroscopy, and magnetic properties. , 2000, Inorganic chemistry.

[19]  J. Mouesca,et al.  Ab Initio (Density Functional) Study of the Exchange Coupling Constant in Di-μ-oxo-Bridged Copper(II) Dimers: A Valence Bond/Broken Symmetry Approach , 2000 .

[20]  P. Stang,et al.  Self-assembly of discrete cyclic nanostructures mediated by transition metals. , 2000, Chemical reviews.

[21]  Gautam R. Desiraju,et al.  The Weak Hydrogen Bond: In Structural Chemistry and Biology , 1999 .

[22]  R. Winpenny.  Families of High Nuclearity Cages , 1999 .

[23]  S. Youngme,et al.  The crystal and molecular structures of di-μ-hydroxy-bis(di-2-pyridylamine)dinitratodicopper(II) and aqua-μ-formato-triformato-bis(di-2-pyridylamine)dicopper(II) monohydrate , 1999 .

[24]  M. Darensbourg,et al.  Oxygen Capture by Sulfur in Nickel Thiolates , 1998 .

[25]  C. Carrano,et al.  Synthesis and Characterization of a Series of Edge-Sharing Octahedral-Tetrahedral-Octahedral Linear Trinuclear Complexes [M(3)(L1O)(4)](2+), Where M = Mn(2+), Co(2+), Ni(2+), Cu(2+), and Zn(2+) and L1OH Is the "Heteroscorpionate" Ligand (2-Hydroxyphenyl)bis(pyrazolyl)methane. , 1998, Inorganic chemistry.

[26]  L. Cronin,et al.  Synthesis and single crystal X-ray structure of a novel trinuclear copper(II) methoxide complex , 1998 .

[27]  S. Alvarez,et al.  Structural Modeling and Magneto-Structural Correlations for Hydroxo-Bridged Copper(II) Binuclear Complexes. , 1997, Inorganic chemistry.

[28]  E. Ruiz,et al.  Toward the Prediction of Magnetic Coupling in Molecular Systems: Hydroxo- and Alkoxo-Bridged Cu(II) Binuclear Complexes , 1997 .

[29]  N. Pinto,et al.  Dicopper Complexes with a Dissymmetric Dicompartmental Schiff Base−Oxime Ligand: Synthesis, Structure, and Magnetic Interactions , 1997 .

[30]  J. G. Haasnoot,et al.  Trinuclear copper(II) coordination compounds with the new ligand 1,9-bis-(3-amino-4H-1,2,4-triazol-5-yl)-3,7-dithianonane; X-ray structures and magnetochemistry , 1996 .

[31]  J. Bridson,et al.  Magnetostructural Correlations in Bis(&mgr;(2)-phenoxide)-Bridged Macrocyclic Dinuclear Copper(II) Complexes. Influence of Electron-Withdrawing Substituents on Exchange Coupling. , 1996, Inorganic chemistry.

[32]  M. Halcrow,et al.  Biomimetic Chemistry of Nickel , 1994 .

[33]  D. Gatteschi.  Molecular Magnetism: A basis for new materials , 1994 .

[34]  J. Ribas,et al.  Tailored magnetic properties in trinuclear copper(II) complexes : synthesis, structure, and magnetic properties of complexes derived from [1,3-propanediylbis(oxamato)]cuprate(II) ([Cu(pba)]2-) , 1993 .

[35]  N. Koga,et al.  Study of the Effect of Structural Factors on Magnetism of Di-μ-alkoxodicopper(II) Complexes by Ab Initio MO Calculations , 1988 .

[36]  J. Charland,et al.  Synthesis, structure, and electrochemistry of a novel macrocyclic dicopper(II) complex. Four one-electron-transfer steps producing binuclear copper(III) and copper(I) species and mixed-valence-state species , 1987 .

[37]  O. Kahn,et al.  Copper(II) and nickel(II) trinuclear species with dithiooxamide derivative ligands: structural, magnetic, spectroscopic, and electrochemical properties , 1986 .

[38]  W. Haase,et al.  Direct theoretical abinitio calculations in exchange coupled copper (II) dimers: Influence of structural and chemical parameters in modeled copper dimers , 1986 .

[39]  F. Dahan,et al.  A further example of a dinuclear copper(II) complex involving monoatomic acetate bridges. Synthesis, crystal structure, and spectroscopic and magnetic properties of bis(.mu.-acetato)bis(7-amino-4-methyl-5-aza-3-hepten-2-onato(1-))dicopper(II) , 1985 .

[40]  L. Banci,et al.  EPR spectra of trinuclear complexes. Octachlorodiadeniniumtricopper(II) tetrahydrate , 1983 .

[41]  J. Lehn,et al.  Dinuclear copper(II) cryptates of macrocyclic ligands: synthesis, crystal structure, and magnetic properties. Mechanism of the exchange interaction through bridging azido ligands , 1982 .

[42]  O. Kahn.  Molecular engineering of coupled polynuclear systems: Orbital mechanism of the interaction between metallic centers , 1982 .

[43]  C. O'connor,et al.  Magnetic properties and crystal structure of an acetate-bridged ferromagnetic copper(II) dimer , 1981 .

[44]  J. Jaud,et al.  Crystal structure and magnetic properties of Cu2(fsa)2en, CH3OH, with H4(fsa)2en = N,N′-bis(2-hydroxy, 3-carboxybenzilidene)-1,2-diaminoethane , 1979 .

[45]  D. Gatteschi,et al.  Angular overlap interpretation of the magnetic properties of copper(II) dimers , 1978 .

[46]  K. Nakamoto.  Infrared and Raman Spectra of Inorganic and Coordination Compounds , 1978 .

[47]  D. Hodgson,et al.  Relation between the singlet-triplet splitting and the copper-oxygen-copper bridge angle in hydroxo-bridged copper dimers , 1976 .

[48]  R. Butcher,et al.  Relation Between Magnetic, Spectroscopic, and Structural Properties of Bis[chloro(N-isopropyl-2-hydroxybenzylidene)aminato-μ-O-copper(II)] and Bis(N-isopropyl-2-hydroxybenzylideneaminato)copper(II) , 1976 .

[49]  E. Sinn.  Bis[nitrato(N-ethyl-2-hydroxybenzylideniminato-.mu.-O)copper(II)]. Novel copper dimer structure , 1976 .

[50]  Roald Hoffmann,et al.  Orbital interactions in metal dimer complexes , 1975 .

[51]  E. Fujita,et al.  Crystal and molecular structure of bis[N-(picolinoyl)-3-amino-1-propoxidoaquocopper(II)] dihydrate. A copper(II) dimer containing a bent four-membered ring , 1974 .

[52]  R. Ramage.  The structure and synthesis of speciosine , 1971 .