Identification of cyc-B₃H₃ with Three Bridging B–H–B Bonds in a Six-Membered Ring

摘要

Irradiation of samples of diborane(6), B_(2)H_(6) and B_(2)D_(6), separately and together, dispersed in solid neon near 4 K with tunable far-ultraviolet light from a synchrotron yielded new infrared absorption lines that are assigned to several carriers. Besides H, B, BH, BH_(2), BH_(3), B_(2), B_(2)H_(2), and B_(2)H_(4), previously identified, a further species is assigned on the basis of quantum-chemical calculations of vibrational wavenumbers and intensities to be cyc -B_(3)H_(3) (D _(3h ), singlet state) in several isotopic variants, which feature three bridging B–H–B bonds in a six-membered ring.