Publication Date:
2015-08-13
Description:
The concept of boronyl (BO) and the BO/H isolobal analogy build an interesting structural link between boron oxide clusters and hydrocarbons. Based upon global-minimum searches and first-principles electronic structural calculations, we present here the perfectly planar C 2 v B 5 O 5 + ( 1 , 1 A 1 ), C 2 v B 5 O 5 ( 2 , 2 A 1 ), and tetrahedral C s B 5 O 5 − ( 3 , 1 A′) clusters, which are the global minima of the systems. Structural and molecular orbital analyses indicate that C 2 v B 5 O 5 + ( 1 ) [B 3 O 3 (BO) 2 + ] and C 2 v B 5 O 5 ( 2 ) [B 3 O 3 (BO) 2 ] feature an aromatic six-membered boroxol (B 3 O 3 ) ring as the core with two equivalent boronyl terminals, similar to the recently reported boronyl boroxine D 3 h B 6 O 6 [B 3 O 3 (BO) 3 ]; whereas C s B 5 O 5 − ( 3 ) [B(BO) 3 (OBO) − ] is characterized with a tetrahedral B − center, terminated with three BO groups and one OBO unit, similar to the previously predicted boronyl methane T d B 5 O 4 − [B(BO) 4 − ]. Alternatively, the 1 – 3 clusters can be viewed as the boron oxide analogs of phenyl cation C 6 H 5 + , phenyl radical C 6 H 5 , and chloromethane CH 3 Cl, respectively. Chemical bonding analyses also reveal a dual three-center four-electron (3c-4e) π hyperbond in C s B 5 O 5 − ( 3 ). The infrared absorption spectra of B 5 O 5 + ( 1 ), B 5 O 5 ( 2 ), and B 5 O 5 − ( 3 ) and anion photoelectron spectrum of B 5 O 5 − ( 3 ) are predicted to facilitate their forthcoming experimental characterizations. The present work completes the B n O n +/0/− series for n = 1–6 and enriches the analogous relationship between boron oxides and hydrocarbons.
Print ISSN:
0021-9606
Electronic ISSN:
1089-7690
Topics:
Chemistry and Pharmacology
,
Physics
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