Bhattacharjee Jayeeta, Harinath Adimulam, Bano Kulsum, Panda Tarun K
Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, 502285 Sangareddy, Telangana, India.
ACS Omega. 2020 Jan 10;5(3):1595-1606. doi: 10.1021/acsomega.9b03598. eCollection 2020 Jan 28.
We report a series of titanium and zirconium complexes supported by dianionic amidophosphine-borane ligands, synthesized by amine elimination and salt metathesis reactions. The Ti complex [{PhP(BH)N}CHTi(NMe)] () was obtained by the reaction between tetrakis-(dimethylamido)titanium(IV) and the protic aminophosphine-borane ligand [{PhP(BH)NH}CH] () at ambient temperature. Both the heteroleptic zirconium complexes-[η-(CH)Zr{PhP(BH)N}CH] () and [[{PhP(BH)N}CH]ZrCl] ()-and the homoleptic zirconium complex [[{PhP(BH)N}CH]Zr] () were obtained in good yield by the salt metathesis reaction of either zirconocene dichloride [η-(CH)ZrCl] or zirconium tetrachloride with the dilithium salt of the ligand [{PhP(BH)NLi}CH] (), which was prepared in situ. The molecular structures of the complexes , , and in their solid states were confirmed by single-crystal X-ray diffraction analysis. Of these complexes, only titanium complex acts as an effective catalyst for the facile hydroboration of terminal alkynes, yielding exclusive -isomers. The hydroboration of organic nitriles yielded diborylamines with a broad substrate scope, including broad functional group compatibility. The mechanism of hydroboration occurs through the formation of titanium hydride as an active species.
我们报道了一系列由双阴离子氨基膦硼烷配体支撑的钛和锆配合物，它们通过胺消除反应和盐复分解反应合成。钛配合物[{PhP(BH)N}CHTi(NMe)] ()是通过四（二甲基氨基）钛（IV）与质子化氨基膦硼烷配体[{PhP(BH)NH}CH] ()在室温下反应得到的。通过二氯二茂锆[η-(CH)ZrCl]或四氯化锆与配体[{PhP(BH)NLi}CH] ()的二锂盐进行盐复分解反应，均以良好的产率得到了杂配锆配合物-[η-(CH)Zr{PhP(BH)N}CH] ()和[[{PhP(BH)N}CH]ZrCl] ()，以及均配锆配合物[[{PhP(BH)N}CH]Zr] ()，其中配体[{PhP(BH)NLi}CH] ()是原位制备的。配合物、和的固态分子结构通过单晶X射线衍射分析得以确认。在这些配合物中，只有钛配合物能作为末端炔烃简便硼氢化反应的有效催化剂，专一性地生成 -异构体。有机腈的硼氢化反应能生成具有广泛底物范围的二硼胺，包括广泛的官能团兼容性。硼氢化反应的机理是通过形成氢化钛作为活性物种来进行的。
