Stereoselective synthesis and reactivity of cis- and trans- dimolybdenum nitrosyl derivatives with the bridging bis(dimethylsilanediyl)di(η5-cyclopentadienyl) ligand. X-ray molecular structures of cis-[{Mo(CO)2(NO)}2(μ-(η5-C5H3)2(SiMe2)2}], trans-[(Mo(CO)(NO)(CNtBu)}2(μ-(η5-C5H3)2(SiMe2)2}], cis-[{Mo2(CO)3(NO)2(PMe3)}{μ-(η5-C 5H3)2(SiMe2)2}] and trans-[{Mo(NO)(CNtBu)2}2(μ-(η5-C5H3)2(SiMe2)2}]

Abstract

New dimolybdenum nitrosyl [Mo(CO)2(NO)2μ-(η5-C5H3)2(SiMe2)2] cis-3 and trans-3 complexes have been isolated from the reaction of the previously reported cis-[Mo(CO)3H2μ-(η5-C5H3)2(SiMe2)2] cis-1 and trans-K2[Mo(CO)32μ-(η5-C5H3)2(SiMe2)2] trans-2 respectively, with p-CH3C6H4SO2N(NO)(CH3) (diazald). The reaction of [Mo(CO)2(NO)2μ-(η5-C5H3)2(SiMe2)2] cis-3 and trans-3 with Lewis bases L (L = tert-butylisocyanide and trimethylphosphine) under appropriate conditions gave monosubstituted [Mo2(CO)3(NO)2Lμ-(η5-C5H3)2(SiMe2)2] complexes (L = CNtBu cis-4; PMe3cis-5 and trans-5), disubstituted [Mo(CO)(NO)L2μ-(η5-C5H3)2(SiMe2)2] (L = CNtBu, cis-6, trans-6; PMe3cis-7 and trans-7) and tetrasubstituted [Mo(NO)L22μ-(η5-C5H3)2(SiMe2)2] complexes (L = CNtBu, cis-8 and trans-8), which were isolated in moderate yields and fully characterized by conventional analytical and spectroscopic methods. Addition of PCl5 under appropriate conditions to a diethyl ether solution of cis-3 or trans-3 afforded the dichloronitrosyl derivatives cis- and trans-[MoCl2(NO)2μ-(η5-C5H3)2(SiMe2)2] cis-9 and trans-9. The 13C and variable temperature 1H NMR spectra of complex cis-9 are consistent with the formation of 18 electron metal centres bridged by two chlorine atoms, providing two cis- and trans-nitrosyl isomers, which interchange rapidly in solution at room temperature through a postulated 16 electron intermediate. Treatment of cis-8 and trans-8 with stoichiometric amounts of PCl5 gave the tetrahalo derivatives [Mo(NO)(CNtBu)Cl22μ-(η5-C5H3)2(SiMe2)2] cis-10 and trans-10 respectively, whereas the oxidation of trans-6 with PCl5 under similar conditions gave a mixture of trans-10 and trans-[Mo2(CO)(NO)2(CNtBu)Cl4μ-(η5-C5H3)2(SiMe2)2] (trans-11). In addition, single crystal X-ray crystallographic analyses were performed for cis-3, cis-5, trans-6 and trans-8. All the complexes show two metal fragments bridged by the μ-(η5-C5H3)2(SiMe2)2 ligand, with different dispositions of the metal fragments.

Stereoselective synthesis and reactivity of cis- and trans- dimolybdenum nitrosyl derivatives with the bridging bis(dimethylsilanediyl)di(η5-cyclopentadienyl) ligand. X-ray molecular structures of cis-[Mo(CO)2(NO)2μ-(η5-C5H3)2(SiMe2)2], trans-[Mo(CO)(NO)(CNtBu)2μ-(η5-C5H3)2(SiMe2)2], cis-[Mo2(CO)3(NO)2(PMe3)μ-(η5-C5H3)2(SiMe2)2] and trans-[Mo(NO)(CNtBu)22μ-(η5-C5H3)2(SiMe2)2]. Available from: http://www.researchgate.net/publication/256790936_Stereoselective_synthesis_and_reactivity_of_cis-_and_trans-_dimolybdenum_nitrosyl_derivatives_with_the_bridging_bis(dimethylsilanediyl)di(5-cyclopentadienyl)_ligand._X-ray_molecular_structures_of_cis-Mo(CO)2(NO)2-(5-C5H3)2(SiMe2)2_trans-Mo(CO)(NO)(CNtBu)2-(5-C5H3)2(SiMe2)2_cis-Mo2(CO)3(NO)2(PMe3)-(5-C5H3)2(SiMe2)2_and_trans-Mo(NO)(CNtBu)22-(5-C5H3)2(SiMe2)2 [accessed Nov 23, 2015].