The Heptahydrodiborate l- Ion

Selected Structural Parameters for the [BgHy] Anion [2]. = bridging hydrogen. 

Coupled Hartree-Fock (CHF) and equation-of-motion (EOM) calculations at the ab initio level for the B-H indirect nuclear spin-spin coupling constants in [BgHy] have been performed. The values for both methods are 35.26 (CHF) and 29.52 Hz (EOM) for J(B.H ) and 109.47 (CHF) and 91.74 Hz (EOM) for J(B,Ht) [3]. 

diborene, has been studied by ab initio configuration interaction calculations using a double zeta plus polarization basis set. The D h molecule has three low-lying electronic states, 1 Ag, and Zg, just like the O2 molecule, but BgHg has only eight valence electrons. 

Structural parameters of the cited electronic states are r(B=B) =1.498, 1.507, 1.515 A and r(B H)=1.170,1.169,1.169 A, respectively. The bond shortening from H2B-BH2 to HB=BH of 11%, comparable with those from H3C-CH3 to H2C=CH2 (12.7%), indicates a slightly weaker double bond between the boron atoms. The relative energies of the three states are 0, 16.6, and 26.3 kcal/mol, respectively, and the dissociation energy of the ground state ( I ) is 107 kcal/mol. 

Similar calculations for aminoborene, HB=B-NH2, and 1,2-diaminoborene, H2N-B=B-NH2, were carried out structural data and relative energies are given in Table 2/24. 

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