Electronic structures and properties of dianionic pentacarbonyls [TM(CO) 5 ] 2− (TM = Cr, Mo, W)

• Published in: Physical chemistry chemical physics : PCCP Vol. 23; no. 34; pp. 18640 - 18646
• Main Authors: Pei, Gerui, Shu, Cong-Cong, Li, Mengyang, Sun, Zhong-Ming, Yang, Tao
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 14.09.2021
• Subjects: Bonding; Carbon monoxide; Chromium; Crystallography; Density functional theory; Energy of dissociation; Free energy; Heat of formation; Mathematical analysis; Molybdenum; Transition metals; Tungsten
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d1cp01592c

Density functional theory (DFT) calculations were employed to study the stabilities, electronic structures, and vibrational and bonding properties of dianionic pentacarbonyls [TM(CO) 5 ] 2− (TM = Cr, Mo, W). A D 3h symmetry structure with singlet state was found to be the ground state and C–O stretching vibrational frequencies range from 1719 to 1766 cm −1 , which are in excellent agreement with the experimental observations. The calculation results on bond dissociation energy for the CO loss revealed their stabilities. By employing energy decomposition analysis (EDA), the bonding nature between TM 2− and (CO) 5 was disclosed, in which the [TM(d)] 2− →(CO) 5 π backdonations contribute largely to the orbital interactions while σ donation from the lone pair of CO to metal contributes moderately. Compared with those in the isoelectronic neutral hexacarbonyls TM(CO) 6 , the π backdonations are obviously larger in [TM(CO) 5 ] 2− because there are two extra electrons in ( n − 1)d AOs of the center transition metal.