First B-Organyloxy-Substituted Iminoboranes:  Preparation, Stabilization, and Reactivity

Abstract

The amino(halo)(organyloxy)boranes ROB(X)N(H)R‘ (R = 2,6-tBu2C6H3, X = Cl, R‘ = tBu (7), SiMe3 (8), 2,6-iPr2C6H3 (9), 2,4,6-Me3C6H2 (10), 2,4,6-tBu3C6H2 (11); R = 2,6-C6H5)2C6H3, X = Cl, R‘ = tBu (12); R = 2,6-tBu2C6H3, X = F, R‘ = tBu (13), 2,6-iPr2C6H3 (14); R = tBu3C, X = F, R‘ = iPr (15), tBu (16), SiMe3 (17)) were dehydrohalogenated with tert-butyllithium at low temperature. The reaction involved the intermediate formation of an aryloxy(imino)borane in the case of 7, 9, 11, and 12. The diazadiboretidines [ROBNR‘]2 (R = 2,6-tBu2C6H3, R‘ = tBu (18), SiMe3 (19), 2,6-iPr2C6H3 (20), 2,4,6-Me3C6H2 (21); R = tBu3C, R‘ = iPr (22), SiMe3 (23)) were isolated as the ultimate products of the reactions. The aryloxy(imino)borane 2,6-tBu2C6H3−O−B⋮N-tBu (derived from 7) was reacted with BEt3 and Me3SiN3 to give the corresponding 1,2-addition products across the (B≡N) triple bond (25 and 26, respectively). The compounds were characterized by NMR spectroscopy (1H, 11B, 13C, 29Si), MS (EI and FI), and elemental analyses. X-ray structure determinations are presented for 18, 22, and 26.

Density Functional Calculations of the Anisotropic Effects of Borazine and 1,3,2,4‐Diazadiboretidine

“…It was shown previously that this structure is not subject to Jahn–Teller distortion, as is the case with the square cyclobutadiene 31. 32 The optimized BN bond length is comparable to the previously calculated value (1.47 Å)31 and to the X‐ray structural data for substituted molecules, which range from 1.430 to 1.486 Å 8b. The WBI, which is higher than that of BH 3 NH 3 , points to some electron delocalization,33 as does the π‐bond occupation, which is lower than for the localized BH 2 NH 2 but similar to that of borazine (Table 1).…”

All‐Metal Antiaromaticity in Sb4‐Type Lanthanocene Anions

“…[6] Whereas the cyclic B 2 N 2 fragment was found to be planar (except for in the tetra-tert-butyl derivative), the synthesized B 2 N 2 H 4 derivatives do not follow the expected reactivity of antiaromatic molecules because they survive the thermal elimination of isobutene from the tert-butyl derivative. [6] Them ain reason why these inorganic "aromatic" and "antiaromatic" analogues do not follow the expected behavior is the difference in the electronegativities of nitrogen and boron, resulting in the localization of the p electrons on the more electronegative nitrogen atoms. [7] To discover inorganic aromatic or antiaromatic clusters, which could potentially be used as coordination ligands in solid-state compounds,molecules composed of the same type of atoms need to be considered as they would be more conducive to electron delocalization.…”

The Effect of Substituent on Molecules That Contain a Triple Bond Between Arsenic and Group 13 Elements: Theoretical Designs and Characterizations

“…Therefore, triply bonded RE 13 ≡E 15 R is the next synthetic challenge. To the best of the authors' knowledge, only R 2 BN molecules that contain a B≡N triple bond have been experimentally demonstrated to exist [30][31][32][33][34][35][36][37][38][39][40].…”