NH-functionalized tungsten complexes of 2-(dimethylphosphino)imidazole

Abstract Ligand substitution in W(CO) 4 (NO)(ClAlCl 3 ) with 2-(dimethylphosphino)imidazole (dmpi) bearing an acidic NH functionality afforded W(Cl)(CO)(NO)(bdmpi)(dmpi) ( 1 ) (bdmpi = 1,2-bis(dimethyl-phosphino)imidazole), while the reaction of dmpi with W(Cl)(NO)(P(OMe) 3 ) 4 led to the isolation of W(Cl)(NO)(dmpi) 4 ( 2 ) together with W(Cl)(NO)(bdmpi)(dmpi) 2 ( 3 ). Attempts to replace the chloride by a hydride ligand in 1 – 3 applying various hydride reagents did not lead to stable products. The soluble compound W(Cl)(NO)(dmpe)(dmpi) 2 ( 5 ) was prepared by an alternative route from W(Cl)(NO)[P(OMe) 3 )] 4 via the intermediacy of W(Cl)(NO)(P(OMe) 3 ) 2 (dmpe) ( 4 ). The protection of the NH function in 5 was approached applying BuLi and subsequently Me 3 SiCl to afford [W(Cl)(NO)(dmpe)(tmsdmpi) 2 ] (tmsdmpi = 1-trimethylsilyl-2-dimethylphosphino-imidazole) ( 6 ) which could not be isolated in pure form. The reaction of 5 with NaHBEt 3 led to the formation of a deprotonated and nitrogen-coordinated salt Na[W(NO)(dmpe)(dmpi)(tebdmpi)] ( 7 ) (tebdmpi = 2-dimethylphosphino-3-triethylboro-imidazole). Compound 7 crystallized from CH 3 CN to establish a one-dimensional chain structure in the solid state. The structures of compounds 1 – 5 and 7 were studied by single-crystal X-ray diffraction.