Comparing the asymmetric dppf-type ligands with their semi-homologous counterparts

Publication date: Available online 31 January 2018 Source:Journal of Organometallic Chemistry Author(s): Petr Vosáhlo, Ivana Císařová, Petr Štěpnička Two series of asymmetric ferrocene diphosphines, namely the dppf-type ligands R2PfcPPh2 (protected as BH3 adducts; fc = ferrocene-1,1′-diyl) and their singly-homologous counterparts R2PfcCH2PPh2 (both in free and BH3-protected form), with diverse PR2 groups (R = cyclohexyl, isopropyl and tert-butyl), were prepared and further converted into the respective phosphine selenides, R2P(Se)fcP(Se)Ph2 and R2P(Se)fcCH2P(Se)Ph2, which were in turn used to evaluate the electronic properties of these diphosphines through 1 J SeP coupling constants. When reacted with [PdCl2(MeCN)2] or [PdCl2(cod)] (cod = cycloocta-1,5-diene), the dppf-type ligands exclusively afforded the chelate complexes [PdCl2(R2PfcPPh2-κ2 P,P′)], whereas the more flexible, homologous ligands produced mixtures mainly containing the similar chelate complexes [PdCl2(R2PfcCH2PPh2-κ2 P,P′)] and the P,P′-bridged dimers [PdCl2(μ(P,P′)-R2PfcCH2PPh2)]. Graphical abstract

Source: Journal of Organometallic Chemistry - January 31, 2018 Category: Chemistry Source Type: research