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Endohedral and Exohedral Metalloborospherenes: M@B 40 (M=Ca, Sr) and M&B 40 (M=Be, Mg)
Author(s) -
Bai Hui,
Chen Qiang,
Zhai HuaJin,
Li SiDian
Publication year - 2015
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.201408738
Subject(s) - delocalized electron , atom (system on chip) , metal , valence electron , electron , crystallography , ion , valence (chemistry) , atomic physics , materials science , chemistry , physics , organic chemistry , quantum mechanics , computer science , embedded system , metallurgy
The recent discovery of the all‐boron fullerenes or borospherenes, D 2d B 40 −/0 , paves the way for borospherene chemistry. Here we report a density functional theory study on the viability of metalloborospherenes: endohedral M@B 40 (M=Ca, Sr) and exohedral M&B 40 (M=Be, Mg). Extensive global structural searches indicate that Ca@B 40 ( 1 , C 2v , 1 A 1 ) and Sr@B 40 ( 3 , D 2d , 1 A 1 ) possess almost perfect endohedral borospherene structures with a metal atom at the center, while Be&B 40 ( 5 , C s , 1 A′) and Mg&B 40 ( 7 , C s , 1 A′) favor exohedral borospherene geometries with a η 7 ‐M atom face‐capping a heptagon on the waist. Metalloborospherenes provide indirect evidence for the robustness of the borospherene structural motif. The metalloborospherenes are characterized as charge‐transfer complexes (M 2+ B 40 2− ), where an alkaline earth metal atom donates two electrons to the B 40 cage. The high stability of endohedral Ca@B 40 ( 1 ) and Sr@B 40 ( 3 ) is due to the match in size between the host cage and the dopant. Bonding analyses indicate that all 122 valence electrons in the systems are delocalized as σ or π bonds, being distributed evenly on the cage surface, akin to the D 2d B 40 borospherene.