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The HNBeCO complex is generated via the reaction of a beryllium atom with a HNCO molecule in a solid neon matrix, which is identified via infrared absorption spectroscopy with isotopic substitutions. The complex is characterized to have a linear structure with a very short Be–N bond distance. Bonding analyses indicate that the complex involves an unprecedented HNBeCO triple bond consisting of two degenerate electron-sharing π bonds and a dative σ bond with the π bonds being much stronger than the σ bond. [ABSTRACT FROM AUTHOR]

Heteronuclear BeFe(CO)4− anion complex is generated in the gas phase, which is detected by mass‐selected infrared photodissociation spectroscopy in the carbonyl stretching frequency region. The complex is characterized to have a Be−Fe bonded Be−Fe(CO)4− structure with C3v symmetry and all of the four carbonyl ligands bonded on the iron center. Quantum chemical studies indicate that the complex has a quite short Be−Fe bond. Besides one electron‐sharing σ bond, there are two additional, albeit weak, Be ← Fe(CO)4− dative π bonding interactions. The findings imply that metal–metal bonding between s‐block and transition metals is viable under suitable coordination environment. [ABSTRACT FROM AUTHOR]

Homoleptic dinuclear beryllium carbonyl cation complexes have been produced and characterized in the gas phase. Infrared photodissociation spectroscopic and theoretical results confirm that Be2(CO)5+ is a coordination saturated complex that can be assigned to a mixture of two almost isoenergetic structural isomers. Besides a beryllium–beryllium single‐bonded (OC)2Be‐Be(CO)3+ isomer, another structure involving an unusual end‐on and side‐on bridging carbonyl ligand with very low carbonyl stretching frequency is identified. [ABSTRACT FROM AUTHOR]

The reactions of laser‐ablated beryllium atoms with dinitrogen and carbon monoxide mixtures form the end‐on bonded NNBeCO and side‐on bonded (η2‐N2)BeCO isomers in solid argon, which are predicted by quantum chemical calculations to be almost isoenergetic. The end‐on bonded complex has a triplet ground state while the side‐on bonded isomer has a singlet electronic ground state. The complexes rearrange to the energetically lowest lying NBeNCO isomer upon visible light excitation, which is characterized to be an isocyanate complex of a nitrene derivative with a triplet electronic ground state. A bonding analysis using a charge‐ and energy decomposition procedure reveals that the electronic reference state of Be in the NNBeCO isomers has an 2s02p2 excited configuration and that the metal‐ligand bonds can be described in terms of N2→Be←CO σ donation and concomitant N2←Be→CO π backdonation. The results demonstrate that the activation of N2 with the N−N bond being completely cleaved can be achieved via coupling with carbon monoxide mediated by a main group atom. [ABSTRACT FROM AUTHOR]

The preparation and spectroscopic identification of the complexes NNBe(η2‐N2) and (NN)2Be(η2‐N2) and the energetically higher lying isomers Be(NN)2 and Be(NN)3 are reported. NNBe(η2‐N2) and (NN)2Be(η2‐N2) are the first examples of covalently side‐on bonded N2 adducts of a main‐group element. The analysis of the electronic structure using modern methods of quantum chemistry suggests that NNBe(η2‐N2) and (NN)2Be(η2‐N2) should be classified as π complexes rather than metalladiazirines. [ABSTRACT FROM AUTHOR]

The reactions of beryllium atoms with dioxygen A were renvestigated by matrix isolation infrared absorption spectroscopy. Besides the previously reported linear OBeO and cyclic Be2O2 molecules, two interconvertible beryllium iA annealing ozonide complexes were prepared and characterized. The BeOBe (π2O3)complex was formed on annealing, which is characterized to be a side-on bonded ozonide complex with a planar C2n structure. The BeOBe (π2O3) complex isomerized to the BeOBe (π1O3) isomer under visible light excitation, which is an end- on bonded ozonide complex with planar Q symmetry. These two isomers are interconvertible; that is, visible light induces the conversion of the side-on bonded complex to the end-on bonded isomer, and vice versa on annealing. In addition, evidence is also presented for the linear BeOBeOBe duster. [ABSTRACT FROM AUTHOR]