Formation of the Fluorescent Complexes [(carbene)₂M^I^I(CN)₂] (M = Ni, Pd, Pt) by C−C Bond Cleavage of CH₃CN

Abstract

In the presence of NaH and KOBut, 1-(9-anthracenylmethyl)-3-octylimidazolium chloride (1a) or 1-(9-anthracenylmethyl)-3-ethylimidazolium iodide (1b) was treated with Ni(OAc)2, Pd(OAc)2, or Pt(cod)Cl2 in CH3CN/THF solution to afford the fluorescent complexes [1-(9-anthracenylmethyl)-3-alkylimidazol-2-ylidene]2M(CN)2 (2a, alkyl = C8H17, M = Ni; 2b, alkyl = C2H5, M = Ni; 3a, alkyl = C8H17, M = Pd; 3b, alkyl = C2H5, M = Pd; 4a, alkyl = C8H17, M = Pt; 4b, alkyl = C2H5, M = Pt). The metal(II) center has a square-planar geometry, and pairs of 1-(9-anthracenylmethyl)-3-alkylimidazol-2-ylidene and CN- ligands are in a trans configuration. The CN- ligand in 2−4 derives from C−C bond cleavage in the CH3CN solvent. The fluorescent emission spectra of 1−4 are determined.