34843nas a2200181 45000080041000002450146000412100071001872600008002583000012002664900007002785203413300285100002234418700002134440700002334461700001734484700002534501856013534526 2025 eng d00aHeterolytic cleavage of the B–H bond in H3B·L (L = THF, NMe2H) by an electrophilic Ir(iii) pincer complex [Ir(H)(PMe3)(tBu4POCOP)][BAr F4]0 aHeterolytic cleavage of the B–H bond in H3B L L THF NMe2H by an  cNOV a476-4910 v553 a
Six- and five-coordinate iridium complexes, [Ir(H)Cl(PMe3)(tBu4POCOP)] (2) (tBu4POCOP = κ3-C6H3-2,6-(OPtBu2)2) and [Ir(H)(PMe3)(tBu4POCOP)][BArF4] (3), respectively, have been synthesized and characterized. The reactivity of the electrophilic 16-electron iridium(III) complex 3 with H2, H3B·THF, H3B·NMe2H, and H3B·NMe3 was investigated. The reaction of complex 3 with H2 resulted in the formation of trans-[Ir(H)(η2-H2)(PMe3)(tBu4POCOP)][BArF4] complex 5. Complex 3 was found to activate the B–H bonds in H3B·THF and H3B·NMe2H (DMAB) in a heterolytic fashion. The reaction of complex 3 with H3B·THF at 298 K afforded trans-[Ir(H)2PMe3(tBu4POCOP)] complex 6 and a boronium compound, [H2B(THF)2][BArF4]. Monitoring the reaction from 179 to 298 K by NMR spectroscopy revealed the formation of a σ-borane intermediate, trans-[Ir(H)(η1-HBH2·THF)PMe3(tBu4POCOP)][BArF4] (3a-Int), en route to the final products observed at 298 K. The formation of this intermediate species was also investigated by density functional theory (DFT) calculations. The reaction of complex 3 with H3B·NMe2H at 298 K yielded a mixture of complexes 3 and 5 and a cyclic diborazane [H2BNMe2]2. The reaction was found to proceed via intermediates, a σ-borane complex, trans-[Ir(H)(η1-HBH2·NMe2H)PMe3(tBu4POCOP)][BArF4] (3b), complex 6, [(NHMe2)2BH2][BArF4], and H2B[double bond, length as m-dash]NMe2. Complex 3 exhibited no reactivity with H3B·NMe3.

 

1 aPradhan, Mitarani1 aSurati, Zeel, Y.1 aPal, Apurba, Kumar1 aVanka, Kumar1 aJagirdar, Balaji, R. uhttps://library.ncl.res.in/content/heterolytic-cleavage-b%E2%80%93h-bond-h3b%C2%B7l-l-thf-nme2h-electrophilic-iriii-pincer-complex