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In search of the smallest boroxol‐type heterocyclic ring system: Planar hexagonal B 3 S 3 + cluster with double 6π/2σ aromaticity
Author(s) -
Zhang LiJuan,
Feng LinYan,
Bian He,
Pei Ling,
Li DaZhi,
Zhai HuaJin
Publication year - 2020
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.26229
Subject(s) - aromaticity , borazine , chemistry , cluster (spacecraft) , ring (chemistry) , boron , crystallography , double bond , coupled cluster , computational chemistry , chemical physics , molecule , organic chemistry , boron nitride , computer science , programming language
Boroxol (B 3 O 3 ) rings and relevant hexagonal B 3 S 3 structural blocks are ubiquitous in boron oxide/sulfide glasses, crystals, and high‐temperature liquids. However, the isolation of an ultimate heterocyclic B 3 O 3 or B 3 S 3 cluster in the free‐standing form, with as few as six atoms, has been unsuccessful so far. We report on computational design of the simplest case of such a system: the highly symmetric D 3 h B 3 S 3 + ( 1 A 1 ′) cluster. It is the well‐defined global minimum on the potential energy surface, following global searches and electronic structure calculations at the B3LYP and single‐point CCSD(T) levels. Chemical bonding analysis reveals an ideal system with skeleton Lewis BS σ single bonds and unique double 6π/2σ aromaticity, which underlies its stability. The cluster turns out to be an inorganic analog of the 3,5‐dehydrophenyl cation, a typical double π/σ aromatic system. It offers an example for chemical analogy between boron‐based heterocyclic clusters and aromatic hydrocarbons. Double π/σ aromaticity is also a new concept in heterocyclic boron clusters. Previous systems such as borazine, boroxine, and boronyl boroxine only deal with π aromaticity as in benzene.