Reactions of POCOP pincer palladium benzylthiolate complexes with BH3·THF: Isolation and characterization of unstable POCOP-Pd(η1-HBH3) complexes

Publication date: 1 March 2019Source: Journal of Organometallic Chemistry, Volume 882Author(s): Jie Zhang, Yazhou Ding, Qiang-Qiang Ma, Bula Cao, Jiarui Chang, Shujun Li, Xuenian ChenAbstractIn order to explore the boron mediated C-S bond activation of the thiolate ligand in transition metal thiolate complexes, several bis(phosphinite) (POCOP) pincer ligated palladium complexes bearing a benzylthiolate or mercapto auxiliary ligand, [2,6-(R2PO)2C6H3]PdY (Y = SCH2Ph, R = tBu, 1a, iPr, 1b; Y = SH, R = tBu, 2a, iPr, 2b), were synthesized and fully characterized by multinuclear NMR, FTIR, X-ray crystallography and elemental analysis. The reactions of complexes 1a-b or 2a-b with BH3·THF at room temperature produced exclusively the corresponding tetrahydroborate complexes, [2,6-(R2PO)2C6H3]Pd(η1-HBH3) (R = tBu, 3a; iPr, 3b), through Pd-S bond cleavage. Complexes 3a and 3b are air/moisture sensitive and thermally unstable. X-ray crystallography and FTIR spectra supported a η1-HBH3 monodentate coordination mode for the BH4 ligand in complexes 3a and 3b. The boron mediated C-S bond cleavage was not observed in the reactions of complexes 1a and 1b with BH3·THF perhaps due to the relatively weak Pd-S bond.Graphical abstract

Source: Journal of Organometallic Chemistry - January 9, 2019 Category: Chemistry Source Type: research