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Ge=B ?-Bonding: Synthesis and Reversible [2+2]?Cycloaddition of Germaborenes.

ABSTRACT: Phosphine-stabilized germaborenes featuring an unprecedented Ge=B double bond with short B???Ge contacts of 1.886(2) (4) and 1.895(3)?Å (5) were synthesized starting from an intramolecular germylene-phosphine Lewis pair (1). After oxidative addition of boron trihalides BX3 (X=Cl, Br), the addition products were reduced with magnesium and catalytic amounts of anthracene to give the borylene derivatives in yields of 78?% (4) and 57?% (5). These halide-substituted germaborenes were characterized by single-crystal structure analysis, and the electronic structures were studied by quantum-chemical calculations. According to an NBO NRT analysis, the dominating Lewis structure contains a Ge=B double bond. The germaborenes undergo a reversible, photochemically initiated [2+2] cycloaddition with the phenyl moiety of a terphenyl substituent at room temperature, forming a complex heterocyclic structure with GeIV in a strongly distorted coordination environment.

SUBMITTER: Raiser D

PROVIDER: S-EPMC7028040 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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Ge=B π-Bonding: Synthesis and Reversible [2+2] Cycloaddition of Germaborenes.

Raiser Dominik D Sindlinger Christian P CP Schubert Hartmut H Wesemann Lars L

Angewandte Chemie (International ed. in English) 20200107 8

Phosphine-stabilized germaborenes featuring an unprecedented Ge=B double bond with short B⋅⋅⋅Ge contacts of 1.886(2) (4) and 1.895(3) Å (5) were synthesized starting from an intramolecular germylene-phosphine Lewis pair (1). After oxidative addition of boron trihalides BX<sub>3</sub> (X=Cl, Br), the addition products were reduced with magnesium and catalytic amounts of anthracene to give the borylene derivatives in yields of 78 % (4) and 57 % (5). These halide-substituted germaborenes were chara ...[more]

PMID: 31804742

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