Platinum‐Templated Coupling of B=N Units: Synthesis of BNBN Analogues of 1,3‐Dienes and a Butatriene

The 1:2 reaction of [μ‐(dmpm)Pt(nbe)] 2 (dmpm=bis(dimethylphosphino)methane, nbe=norbornene) with Cl 2 BNR(SiMe 3 ) (R=tBu, SiMe 3 ) yields unsymmetrical (N‐aminoboryl)aminoboryl Pt I 2 complexes by B−N coupling via ClSiMe 3 elimination. A subsequent intramolecular ClSiMe 3 elimination from the tBu‐derivative leads to cyclization of the BNBN unit, forming a unique 1,3,2,4‐diazadiboretidin‐2‐yl ligand. In contrast, the analogous reaction with Br 2 BN(SiMe 3 ) 2 leads, via a twofold BrSiMe 3 elimination, to a Pt II 2 A‐frame complex bridged by a linear BNBN isostere of butatriene. Structural and computational data confirm π electron delocalization over the entire BNBN unit.