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Molybdenum Complexes Bearing the Tris(1‐pyrazolyl)methanesulfonate Ligand: Synthesis, Characterization and Electrochemical Behaviour
Author(s) -
Dinoi Chiara,
Guedes da Silva M. Fátima C.,
Alegria Elisabete C. B. A.,
Smoleński Piotr,
Martins Luísa M. D. R. S.,
Poli Rinaldo,
Pombeiro Armando J. L.
Publication year - 2010
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.201000018
Subject(s) - chemistry , moiety , ligand (biochemistry) , molybdenum , medicinal chemistry , crystallography , bridging ligand , chelation , single crystal , stereochemistry , crystal structure , inorganic chemistry , biochemistry , receptor
The tris(1‐pyrazolyl)methanesulfonate lithium salt Li(Tpms) [Tpms = SO 3 C(pz) 3 – ] reacts with [Mo(CO) 6 ] in NCMe heated at reflux to yield Li[Mo(Tpms)(CO) 3 ] ( 1 ), which, upon crystallization from thf, forms the coordination polymer [Mo(Tpms)(CO) 2 (μ‐CO)Li(thf) 2 ] n ( 2 ). Reaction of 1 with I 2 , HBF 4 or AgBF 4 yields [Mo(Tpms)I(CO) 3 ] ( 3 ), [Mo(Tpms)H(CO) 3 ] ( 5 ) or [Mo(Tpms)O 2 ] 2 (μ‐O) ( 7 ), respectively. The high‐oxidation‐state dinuclear complexes [{Mo(Tpms)O(μ‐O)} 2 ] ( 4 ) and [{Mo(tpms)OCl} 2 ](μ‐O) ( 6 ) are formed upon exposure to air of solutions of 3 and 5 , respectively. Compounds 1 – 7 , which appear to be the first tris(pyrazolyl)methanesulfonate complexes of molybdenum to be reported, were characterized by IR, 1 H and 13 C NMR spectroscopy, ESI‐MS, elemental analysis, cyclic voltammetry and, in the cases of Li(Tpms) and compounds 2 , 4· 2CH 3 CN, 6· 6CHCl 3 and 7 , by X‐ray diffraction analyses. Li(Tpms) forms a 1D polymeric structure {i.e., [Li(tpms)] n } with Tpms as a tetradentate N 2 O 2 chelating ligand that bridges two Li cations with distorted tetrahedral coordination. Compound 2 is a 1D coordination polymer in which Tpms acts as a bridging tetradentate N 3 O ligand and each Li(thf) 2 + moiety is coordinated by one bridging CO ligand and by the sulfonyl group of a contiguous monomeric unit. In 4 , 6 and 7 , the Tpms ligand is a tridentate chelator either in the NNO (in 4 ) or in the NNN (in 6 and 7 ) fashion. Complexes 1 , 3 and 5 exhibit, by cyclic voltammetry, a single‐electron oxidation at oxidation potential values that indicate that the Tpms ligand has an electron‐donor character weaker than that of cyclopentadienyl.