Spectroscopic and Structural Properties of Bridge-Functionalized Dinuclear Coinage-Metal (Cu, Ag, and Au) NHC Complexes: A Comparative Study

Hydroxymethyl-functionalized methylene-bridged dinuclear N-heterocyclic bis­(NHC) complexes with Ag­(I) (2), Cu­(I) (3) and Au­(I) (4) have been synthesized and characterized by spectroscopic methods and X-ray diffraction studies. Depending on the metal employed, different isomers are formed. The structural properties and differences of all three new compounds are compared to those of previously reported nonfunctionalized methylene-bridged analogues. DFT calculations were conducted to gain a better understanding of the molecular arrangement observed.