New trans-configured acetylide-cyanide platinum(II) anions: Spectroscopic and optical studies

Resumen

A novel series of phosphorescent stable mixed acetylide-cyanide anionic (NBu4)2[trans-Pt(C≡CR)2(CN)2] (R = Tol (1), C6H4CF3-4 (2), C 5H4N-4 (3), Np (4)) complexes were prepared by reactions of the neutral [trans-Pt(C≡CR)2(PPh3)2] precursors with excess (NBu4)CN. The formation of 1-4 takes place through monoanionic [trans-Pt(C≡CR)2(CN)(PPh3)] - intermediate species, as confirmed by the isolation of the naphthyl derivative (NBu4)[trans-Pt(C≡CNp)2(CN)(PPh 3)] (5). Further substitution of PPh3 in 5 by CN tBu gives (NBu4)[trans-Pt(C≡CNp)2(CN) (CNtBu)], containing three different isoelectronic ligands. The complexes have been characterized (1H, 13C, 195Pt NMR, IR, MALDI-TOF), including X-ray crystallography for 2, 4, and 6, and their spectroscopic and optical properties compared to those of the related homoleptic [Pt(C≡CR)4]2- complexes. Time-dependent density functional theory (TD-DFT) calculations were performed for anions 12- and 42- and three different conformers of 6- to provide further insight into the nature of the electronic transitions. © 2013 American Chemical Society.