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Ge=B π‐Bonding: Synthesis and Reversible [2+2] Cycloaddition of Germaborenes
Author(s) -
Raiser Dominik,
Sindlinger Christian P.,
Schubert Hartmut,
Wesemann Lars
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201914608
Subject(s) - chemistry , cycloaddition , intramolecular force , natural bond orbital , substituent , moiety , phosphine , lewis acids and bases , oxidative addition , phosphinidene , double bond , crystal structure , crystallography , medicinal chemistry , photochemistry , stereochemistry , catalysis , polymer chemistry , computational chemistry , organic chemistry , density functional theory
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 3 (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 Ge IV in a strongly distorted coordination environment.