modelling of chelate stabilized tetrylene derivatives

• Published in: RSC advances 2024-03, Vol.14 (15), p.1161-1171
• Main Authors: Tomut, Alex-Cristian, Aghion, Iulia-Andreea, Septelean, Raluca, Porumb, Ioan-Dan, Moraru, Ionut-Tudor, Nemes, Gabriela
• Format: Article
• ISSN: 2046-2069
• DOI: 10.1039/d4ra01515k

The steric and electronic effects of specific ligands can play crucial roles in stabilizing unsaturated tetrylene species. In this work, hybrid density functional theory (DFT) methods, quantum theory of atoms in molecules (QTAIM) investigations and natural bond orbital (NBO) calculations are employed to evaluate the stabilization of low-valent E( ii ) centers (E = Si, Ge, Sn, Pb) through the chelating effect generated by an electron-rich ligand containing the P&z.dbd;C-P&z.dbd;X moiety (X = O or S). Based on several types of analyses, such as the bond dissociation energy (BDE) or the interplay between attractive ( i.e. , charge-transfer) and repulsive ( i.e. , Pauli-exchange) effects, we highlight that the stabilization energy induced by chelation is up to ca. 70 kcal mol −1 for silylenes, yet slightly decreases within the heavier analogues. Moreover, it is emphasized that chelate-stabilized silylenes can form highly stable hybrid metal-metalloid complexes with transition metals ( e.g. , gold). Due to push-pull effects occurring in the X→Si( ii )→Au fragment, the Si( ii )→Au bonding is significantly stronger than the X→Au, P(sp 2 )→Au or π(C&z.dbd;P)→Au donor-acceptor bonds, which are potentially formed by the electron-rich P&z.dbd;C-P&z.dbd;X unit with the AuCl fragment. These findings are supported by energy decomposition analysis (EDA) calculations. The steric and electronic effects of specific ligands can play crucial roles in stabilizing unsaturated tetrylene species.