Second harmonic generation by bimetallic complexes containing ferrocenyl and molybdenum or tungsten mononitrosyl redox centres

Abstract

Several new molybdenum and tungsten mononitrosyl complexes have been synthesised and their non-linear optic properties investigated using the Kurtz powder test; although complexes containing chiral ligands and, in three examples, resolved chiral molybdenum or tungsten mononitrosyl centres, have been found to give second harmonic generation intensities of less than 0.3 times urea, three complexes containing polarisable ligands, namely [Mo(NO)LCl(NHC₆H₄-4-NN-C₆H₄-4′-Fc)]{Fc =[(η)⁵-C₅H₅)Fe (η⁵-C₅H_4^–)], L = HB(3,5-Me₂C₃N₂H)₃}, [W(NO)LCl(NHC₆H₃-(3-Me)-4-NN-C₆H₄-4′-Fc)] and [Mo(NO)LCl(NHC₆H₃-(3-Me)-4-NN-C₆H₄4′-Fc)], gave respective intensities of 59, 53 and 123 times urea.