Highly fluorescent complexes with 3-isocyanoperylene and...

The perylene derivatives 3-isocyanoperylene (Per-N≡C) (4a) and N-(2,5-di-tert-butylphenyl)-9-isocyano-perylene-3,4-dicarboximide (PMI-N≡C) (4b) were prepared and used to synthesize gold complexes [AuX(CNR)] (X = C6F5 (5a,b), C6F4-O(n)Bu-p (6b)). The reaction of 5b and 6b with HNEt2 led to the carbene complexes [AuX{C(NEt2)(NHR)}] (7b, 8b), respectively. The molecular structure of complexes 7b and 8b have been determined by X-ray diffraction analysis showing intermolecular π-stacking of the perylene groups and C6F5 rings and no Au···Au interactions. The derivative compounds [M(CO)5(CNR)] (M = Cr (9a,b), Mo (10a,b) or W (11a,b)) and trans-[Pd(CNR)2(C6F3Cl2)2] (12a,b) were also prepared. All complexes exhibit fluorescence associated with the perylene fragment with emission quantum yields, in solution at room temperature, in the range 0.05-0.93 and emission lifetimes ~ 4 ns. DFT calculations were performed of the absorption spectra of the ligands Per-N≡C and PMI-N≡C and representative complexes [Au(C6F5)(CNR)], [Cr(CO)5(CNR)], showing a perylene-dominated intraligand π-π* emissive state, from the HOMO and LUMO orbitals of the perylene chromophore, but with significantly different absorption maxima by the influence of the metal fragment, particularly significant in the Per-N≡C derivatives.