Structural Predictions And Stabilities Of Novel Organo-Boron Species

Hydrogenated boron-carbon clusters, i.e., organo-borons, have receivedconsiderable attentions both theoretically and experimentally. Herein, using thetopology searching strategy, we systematically explore the structures and stabilities ofsmall organo-borons with CBHz(z≤8) and CxB3-xHz(x=1,2, z≤14) stoichiometry,with particular interests in the intrinsic stabilities of the organo-boron radicals.At the CCSD(T)/aug-cc-pVQZ//B3LYP/aug-cc-pVTZ andCCSD(T)/aug-cc-pVQZ//MP2/aug-cc-pVTZ levels, the stabilities of these globalminima organo-boron species were evaluated by considering dissociation pathwaysand the average heat of hydrogenation (E). Aside from the five already studiedradicals (CBH2, CBH4, C2BH2, C2BH4and CB2H3), we predict six novel radicals, i.e.,CBH6, C2BH6, C2BH8,CB2H, CB2H5and CB2H7, which could be detected undersuitable circumstances. However, observation of the highly hydrogenated CB2H9radical is much less likely due to its minute stability towards H-extrusion. Thecomputationally determined stable/meta-stable maximum hydrogenation numbers forCB, C2B and CB2(6,8and8respectively) are in excellent agreement with a simpleelectron-counting model for CxBychains. The newly predicted organo-boron radicalsawait future laboratory verification.