The coordinating properties of various organic cyanates, isocyanates, thiocyanates, isothiocyanates, and selenocyanates toward the group 6B metal carbonyls have been examined. Twenty complexes of the type M(CO)s(R-XCN) (where M = Cr or W, X = O, S, or Se, and R = alkyl or aryl) have been prepared and characterized; no R-XCN derivatives of molybdenum carbonyl could be obtained. The infrared and and l3C nuclear magnetic resonance spectra of the complexes indicate that these ligands coordinate through the cyano nitrogen rather than the X atom. Complexes of alkyl R-XCN ligands can be prepared by the reaction of the anions [M(CO)sNCX]~w ith alkylating agents such as MeOSOzF or [Et30] [BF4], but the yields are poor. Good yields of the complexes of phenyl cyanate and the alkyl and aryl thiocyanates are obtained by abstraction of iodide from the anions [M(CO)sI]™ by silver ion in acetone solution, followed by addition of the ligand. For the analogous selenocyanate complexes the yields obtained by this method are generally lower. Alkyl and aryl isocyanates and isothiocyanates do not form complexes with any of these metal carbonyls.
Molecular models indicate that they should chelate to metals with the donor groups at 90° with respect to each other. From reactions of the diisocyano ligand DiNC, the following complexes with chelating DiNC ligands have been isolated: Cr(CO),(DiNC), Mo(CO),(DiNC), W(CO),(DiNC), MII(CO)~(D~NC)B~, CpFe(CO)(DiNC)+, and CpFe(CS)(DiNC)+. The characterization of these complexes demonstrates that DiNC can function as a chelating ligand despite its formation of a 13-member chelate ring.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.