Reactivity of Platinum Iminoboryl Complexes toward Covalent Element−Hydrogen Bonds of Opposing Polarity

Reaction of the platinum iminoboryl complex trans-[(Cy3P)2(Br)Pt(BNSiMe3)] (Cy = cyclohexyl) toward covalent element−hydrogen bonds of inverse polarity led to regiospecific formation of the corresponding trans products of 1,2-dipolar addition. Hydrogen bromide reversibly adds to the BN triple bond, and despite the close proximity of the bromide to the trimethylsilyl substituent, the hydrobromination adduct trans-[(Cy3P)2BrPt{B(Br)N(H)SiMe3}] did not show any signs of bromosilane elimination. Furthermore, the reaction of trans-[(Cy3P)2(Br)Pt(BNSiMe3)] and trans-[(Cy3P)2Pt(BNSiMe3)(CCPh)] with the hydroboration reagent catecholatoborane was probed, revealing in both cases clean 1:1 reaction of the reagents. Whereas the reaction product of the latter complex is inherently unstable, both the mono- and the dinuclear hydroboration products of trans-[(Cy3P)2(Br)Pt(BNSiMe3)] could be isolated and fully characterized including X-ray diffraction analysis.