ABSTRACT
The reaction between [(PNpyrP)NiCl] (1, PNpyrP = 2,5-bis((di-iso-propylphosphino)-methyl)-1H-pyrrolide) and TlPF6 in the presence of a monodentate phosphine ligand led to cationic nickel phosphine and phosphite complexes, [(PNpyrP)Ni(PHPh2)][PF6] (2), [(PNpyrP)Ni(PMe3)][PF6] (3), and [(PNpyrP)Ni{P(OMe)3}][PF6] (4). Compound 2 can be deprotonated resulting in the generation of a terminal phosphido complex, [(PNpyrP)Ni(PPh2)] (5). When 3 is subjected to a base, a methyl proton of PMe3 is abstracted to afford [(PNpyrP)Ni(CH2PMe2)] (6), containing a methylene bridge between Ni and the external phosphine. Compounds 2-6 were characterized by single crystal X-ray diffraction in addition to multi-nuclear NMR spectroscopy and elemental analysis.
ABSTRACT
A PNP ligand, PN(pyr)P ((PN(pyr)P)H = 2,5-bis((di-iso-propylphosphino)methyl)pyrrole), which employs a pyrrole unit as a central anionic nitrogen donor, was designed. The corresponding group 10 metal chlorides as well as iridium and ruthenium compounds were isolated. In order to conduct this work, [(PN(pyr)P)Tl] and [(PN(pyr)P)Ag]2 were synthesized and characterized. The thallium and silver species were paramount in the formation of the iridium and ruthenium complexes, which could not be isolated using (PN(pyr)P)H or the corresponding lithium pyrrolide salt. Interestingly, the solid state molecular structure of [(PN(pyr)P)Tl] indicates that the metal center engages in an η(2) intermolecular interaction with the backbone of a neighboring pyrrole molecule instead of the expected bonding to the phosphine arms.
