Structural Studies of [CpMoL2(CO)2]+ (L = NCMe, L2 = 2,2′‐biimidazole) Complexes and Their Inclusion Compounds with Cyclodextrins

Abstract

AbstractProtonation of [CpMo(η3‐C3H5)(CO)2] followed by addition of acetonitrile or 2,2′‐biimidazole (H2biim) gave the complexes [CpMo(NCMe)2(CO)2](BF4) (1) and [CpMo(H2biim)(CO)2](BF4) (2) in good yields. The structures of 1 and 2 were determined by single‐crystal X‐ray diffraction in the orthorhombic Pbca and triclinic P$\bar {1}$ space groups, respectively. Both complexes have similar metal ion coordination environments, which can be envisaged as slightly distorted pseudo‐square pyramids, a coordination geometry commonly compared with a four‐legged piano stool. The two complexes were immobilised in native and permethylated β‐cyclodextrins (β CD and TRIMEB) by methods tailored according to the stabilities and solubilities of the individual components and this gave four adducts with a 1:1 host/guest stoichiometry. The formation of true inclusion compounds was supported by powder X‐ray diffraction (XRD), thermogravimetric analysis (TGA), 13C{1H} CP/MAS NMR and FTIR spectroscopy. In the case of the TRIMEB adduct containing complex 1, the crystal packing arrangement is markedly similar to that previously reported for the corresponding 1:1 TRIMEB adducts of the neutral guests [CpMoX(CO)3] (X = Cl, CH2CONH2), featuring columns in which the macrocycles are arranged along the b axis in a tilted fashion.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)