Premium
5‐Methylthiophene‐2,3‐dithiolene Transition Metal Complexes
Author(s) -
Neves Ana I. S.,
Santos Isabel C.,
Coutinho Joana T.,
Pereira Laura C. J.,
Henriques Rui T.,
Lopes Elsa B.,
Alves H.,
Almeida Manuel,
Belo Dulce
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201402048
Subject(s) - chemistry , isostructural , electron paramagnetic resonance , crystallography , acetonitrile , transition metal , single crystal , crystal structure , ligand (biochemistry) , metal , cyclic voltammetry , inorganic chemistry , electrochemistry , organic chemistry , nuclear magnetic resonance , biochemistry , physics , receptor , electrode , catalysis
Abstract Transition metal complexes based on the new ligand 5‐methylthiophene‐2,3‐dithiolate (α‐mtpdt) and Au, Ni, Fe, Co, Cu Pt and Pd were prepared as tetraalkylammonium and tetraarylphosphonium salts and characterised by cyclic voltammetry, X‐ray diffraction, electron paramagnetic resonance (EPR) spectroscopy and magnetic susceptibility measurements. Except for the Cu complex, which forms a four‐metal cluster [Cu 4 (α‐mtpdt) 3 ] 2– , the metals form complexes of the general formula [M(α‐mtpdt) 2 ]. With Au, Ni and Fe, the complexes are directly obtained from the synthesis as monoanionic salts, and the isostructural crystal structures of [ n Bu 4 N][Ni(α‐mtpdt) 2 ] and [ n Bu 4 N][Au(α‐mtpdt) 2 ] were solved by single‐crystal X‐ray diffraction. For M = Co, Pt and Pd, both monoanionic and dianionic salts were obtained, and the crystal structures of [Ph 4 As] 2 [Co(α‐mtpdt) 2 ] and [Ph 4 As] 2 [Pd(α‐mtpdt) 2 ] were determined by single‐crystal X‐ray diffraction. The Co compound presents a rare tetrahedral coordination geometry. The oxidation of the monoanionic Ni and Au complexes with iodine leads to stable neutral complexes, which are fairly soluble in common organic solvents such as acetonitrile and dichloromethane. The crystal structure of [Ni(α‐mtpdt) 2 ] was solved by single‐crystal X‐ray diffraction. The electrical conductivities of the neutral Ni and Au complexes as polycrystalline compressed pellets are typical of a semiconductor; the room‐temperature conductivities are 5.2 × 10 –7 and 8.7 × 10 –5 S cm –1 , and the activation energies are 325 and 287 meV, respectively.