Platinum Oxoboryl Complexes as Substrates for the Formation of 1:1, 1:2, and 2:1 Lewis Acid–Base Adducts and 1,2‐Dipolar Additions

The oxoboryl complex trans-[(Cy3 P)2 BrPt(B≡O)] (2) reacts with the Group 13 Lewis acids EBr3 (E=Al, Ga, In) to form the 1:1 Lewis acid-base adducts trans-[(Cy3 P)2 BrPt(B≡OEBr3 )] (6-8). This reactivity can be extended by using two equivalents of the respective Lewis acid EBr3 (E=Al, Ga) to form the 2:1 Lewis acid-base adducts trans-[(Cy3 P)2 (Br3 Al-Br)Pt(B≡OAlBr3 )] (18) and trans-[(Cy3 P)2 (Br3 Ga-Br)Pt(B≡OGaBr3 )] (15). Another reactivity pattern was demonstrated by coordinating two oxoboryl complexes 2 to InBr3 , forming the 1:2 Lewis acid-base adduct trans-[{(Cy3 P)2 BrPt(B≡O)}2 InBr3 ] (20). It was also possible to functionalize the B≡O triple bond itself. Trimethylsilylisothiocyanate reacts with 2 in a 1,2-dipolar addition to form the boryl complex trans-[(Cy3 P)2 BrPt{B(NCS)(OSiMe3 )}] (27).