Enhanced thermal stability in organodiborane(4) compounds: synthesis and structural characterization of MeO(Mes)BB(Mes)OMe, Mes2BB(Mes)OMe, Mes2BB(Mes)Ph, and Mes2BB(Mes)CH2SiMe3 (Mes = 2,4,6-Me3C6H2)

Luminescent Symmetrically and Unsymmetrically Substituted Diboranes(4)

“…The B–B bond lengths [ 13 : 1.704(2) Å, 15 : 1.690(3) Å] of both compounds are slightly longer than those in the cyclic 1,4‐diaza‐2,3‐diborinanes above (Table ) and hence in the range of bis(dimethylamino)diborane(4) B–B bonds (Table ). They compare well to Mes 2 BBMesPh [1.706(12) Å[17a]] and the equally unsymmetric diborane(4) reported by Erker et al [1.714(5) Å[17c]] but are slightly longer than the B–B bonds in the two conformers of (o‐tol) 2 BB(o‐tol) 2 (1.686 Å / 1.695 Å[17b]). The diduryldiboranes(4) 13 and 15 show planar coordination arrangement around the boron centers (sum of angles close to 360° at each B).…”

“…For example, the treatment of tetrakis(dimethylamino)diborane(4) with HCl or BX 3 yields the mixed 1,2‐bis(dimethylamino)‐1,2‐dihalodiboranes(4), which can subsequently be converted to various 1,2‐bis(dimethylamino)diboranes(4) by reaction with aryl and/or alkyllithium compounds (Figure ). [10a], [14b], Transformation of the amino into chloro groups provides synthetic access to donor‐free tetraaryldiboranes(4) …”

Anionic Organoboranes: Delicate Flowers Worth Caring for

“…[75] It is thus reasonable to state that the B=B double-bond length is influenced not only by the position of the cation but also by the solvation shell, which modifies the effective size and the Lewis acidity of the cation (cf. [77] to [K(18-c-6)(thf ) 2 ][Mes 2 BNB(Ph)Mes] (1.649(11) Å; [12] •-), [41] and [Li(OEt 2 )] 2 [Mes 2 B=B(Ph)Mes] (1.636(11) Å; [12] 2-): [40] while the injection of the first electron results in a significant shortening of the B-B bond, very little further contraction occurs after the addition of the second electron even though the π-bond order concomitantly increases from 0 to 0.5 to 1.0. Power et al have therefore concluded that this increase is compensated in the second step by the electrostatic repulsion between the two negative charges in the dianion.…”

The Borole Route to Reactive Pentafluorophenyl‐Substituted Diboranes(4)

“…The B−B linkage is shorter than in the adducts 7 b and 8 b (Δ d ≈0.05 Å). For example, its B−B bond length of 1.714(5) Å compares well with mes 2 B−BMes(CH 2 −SiMe 3 ) (1.711(20) Å) or mes 2 B−B(Ph)mes (1.706(12) Å) structures reported by Power et al. ; however, it is slightly longer than the B−B bond length in ( o ‐tol) 2 B−B( o ‐tol) 2 (1.686(10)/1.695(9) Å) reported by Yamashita et al .…”