Observation of Main‐Group Tricarbonyls [B(CO)₃] and [C(CO)₃]⁺ Featuring a Tilted One‐Electron Donor Carbonyl Ligand

Abstract

A combined experimental and theoretical study on the main-group tricarbonyls [B(CO)3 ] in solid noble-gas matrices and [C(CO)3 ](+) in the gas phase is presented. The molecules are identified by comparing the experimental and theoretical IR spectra and the vibrational shifts of nuclear isotopes. Quantum chemical ab initio studies suggest that the two isoelectronic species possess a tilted η(1) (μ1 -CO)-bonded carbonyl ligand, which serves as an unprecedented one-electron donor ligand. Thus, the central atoms in both complexes still retain an 8-electron configuration. A thorough analysis of the bonding situation gives quantitative information about the donor and acceptor properties of the different carbonyl ligands. The linearly bonded CO ligands are classical two-electron donors that display classical σ-donation and π-back-donation following the Dewar-Chatt-Duncanson model. The tilted CO ligand is a formal one-electron donor that is bonded by σ-donation and π-back-donation that involves the singly occupied orbital of the radical fragments [B(CO)2 ] and [C(CO)2 ](+) .

Infrared spectroscopic and theoretical study of the HC2n+1O+ (n = 2–5) cations

“…It is found that these cation complexes dissociate efficiently via the loss of a CO ligand with unfocused infrared laser, indicating that the HC 2n+2 O 2 + (n = 2-5) cations are weakly bound "CO-tagged" [HC 2n+1 O•CO] + (n = 2-5) complexes involving strongly bound HC 2n+1 O + (n = 2-5) core ions. As discussed previously, [55][56][57] CO-tagging usually has a negligible effect on the structure and lowresolution, rotationally unresolved vibrational spectrum of the core ion.…”

Infrared Spectroscopy and Bonding of the B(NN)3+ and B2(NN)3,4+ Cation Complexes

“…The calculated frequencies were scaled by 0.952, which was determined by the vibrational frequency for gas phase N 2 (2330 cm –1 ) and the calculated value. The energy decomposition analysis with the natural orbitals of chemical valence (EDA-NOCV) method was used to study the chemical bonding between boron and the dinitrogen ligand, which was performed at the BP86/TZ2P level ,, with the optimized geometries by using the ADF 2014.10 program package. , The EDA-NOCV bonding analyses focus on the interaction energy of a bond A–B in a frozen geometry formed between two parts A and B in particular electronic reference states, which has proven to be a powerful theoretical tool to understand the donor–acceptor bonding in coordination complexes such as metal–carbonyl complexes and dinitrogen complexes. − ,− …”

Reaction Mechanism of the Hydrogermylation/Hydrostannylation of Unactivated Alkenes with Two‐Coordinate EII Hydrides (E=Ge, Sn): A Theoretical Study

“…[27] The latter term can be separated into contributions that come from pairwise orbital interactions, which makes it possible to identify the dominant orbitals of the interactions in the transition state. For ad etailed description of the method [27] and for recent pertinent examples, [22,28] we refer to the literature. The EDA-NOCV calculations were carried with the M06-2X functional [23] by using uncontracted Slater-type orbitals that have triple-z quality augmented by two sets of polarization functions (TZ2P).…”