Observation of Aromatic B(CO) ( = 1-7) as Boron Carbonyl Analogs of Benzene.

CO as a typical σ-donor is one of the most important ligands in chemistry, while planar B is experimentally known as the most prominent magic-number boron cluster analogous to benzene. Joint gas-phase mass spectroscopy, collision-induced dissociation, and first-principles theory investigations performed herein indicate that B reacts with CO successively under ambient conditions to form a series of boron carbonyl complexes B(CO) up to = 7, presenting the largest boron carbonyl complexes observed to date with a quasi-planar B core at the center coordinated by CO ligands around it. Extensive theoretical analyses unveil both the chemisorption pathways and bonding patterns of these aromatic B(CO) monocations which, with three delocalized π bonds well-retained over the slightly wrinkled B moiety, all prove to be boron carbonyl analogs of benzene tentatively named as boron carbonyl aromatics (BCAs).

Investigation of Pb-B Bonding in PbB(BO) ( = 0-2): Transformation from Aromatic PbB to Pb[B(BO)] Complexes with BB Triple Bonds.

Boron has been found to be able to form multiple bonds with lead. To probe Pb-B bonding, here we report an investigation of three Pb-doped boron clusters, PbB, PbBO, and PbBO, which are produced by a laser ablation cluster source and characterized by photoelectron spectroscopy and calculations. The most stable structures of PbB, PbBO, and PbBO are found to follow the formula, [PbB(BO)] ( = 0-2), with zero, one, and two boronyl ligands coordinated to a triangular and aromatic PbB core, respectively.

[Cs©C] and [Na©C]: perfect planar alkaline-metal-centered polyynic cyclo[]carbon complexes with record coordination numbers.

Searching for the maximum coordination number (CN) in planar species with novel bonding patterns has fascinated chemists for many years. Using the experimentally observed polyynic cyclo[18]carbon C and theoretically predicted polyynic cyclo[14]carbon C as effective ligands and based on extensive first-principles theory calculations, we predict herein their perfect planar alkaline-metal-centered complexes Cs©C (1) and Na©C (4) which as the global minima of the systems possess the record coordination numbers of CN = 18 and 14 in planar polyynic species, respectively. More interestingly, detailed energy decomposition and adaptive natural density partitioning bonding analyses indicate that the hypercoordinate alkaline-metal centers in these complexes exhibit obvious transition metal behaviors, with effective in-plane (π-6s)σ, (π-7p)σ, and (π-5d)σ coordination bonds formed in Cs©C (1) and (π-3s)σ, (π-3p)σ, and (π-3d)σ coordination interactions fabricated in Na©C (4) to dominate the overall attractive interactions between the metal center and its cyclo[]carbon ligand.

Boron-lead multiple bonds in the PbBO and PbBO clusters.

Despite its electron deficiency, boron can form multiple bonds with a variety of elements. However, multiple bonds between boron and main-group metal elements are relatively rare. Here we report the observation of boron-lead multiple bonds in PbBO and PbBO, which are produced and characterized in a cluster beam.