Group VI metal pentacarbonyl complexes of 1,2,4-triazoles

Abstract

The synthesis of chromium and tungsten pentacarbonyl complexes with 4-methyl and 4-phenyl-1,2,4-triazole is reported. The nature of the lowest energy absorption in the ultraviolet spectra of these complexes has been examined and shown to be principally a ligand field band. The triazoles are shown to be acting as monodentate ligands by infrared and 1H nuclear magnetic resonance spectroscopy. The compounds show strong solvent dependence in the 1H NMR and these effects are explained by solvent—solute interaction. The temperature dependence of the 1H NMR spectrum of W(CO) 5(4-phenyl-1,2,4-triazole) has also been examined.