A hemilabile binucleating pincer ligand for self-assembly of coordination oligomers and polymers
作者:Chang-Qiu Zhao、Michael C. Jennings、Richard J. Puddephatt
DOI:10.1039/b716035f
日期:——
The bis(PNP)-donor pincer ligand 1,4-C6H4N(CH2CH2PPh2)2}2, 1, contains weakly basic nitrogen donor atoms because the lone pairs of electrons are conjugated to the bridging phenylene group, and this feature is used in the synthesis of oligomers and polymers. The complexes [Pd2X2(µ-1)](OTf)2, X = Cl, Br or OTf, contain the ligand 1 in bis(pincer) binding mode (µ-κ6-P4N2), but [Pd4Cl6(µ3–1)2]Cl2 contains the ligand in an unusual unsymmetrical µ3-κ5-P4N binding mode. The bromide complex is suggested to exist as a polymer [Pd2Br4(µ4-1)}n] with the ligands 1 in µ4-κ4-P4 binding mode. The methylplatinum(II) complexes [Pt2Me4(µ-1)] and [Pt2Me2(µ-1)](O2CCF3)2 contain the ligand 1 in µ-κ4-P4 and µ-κ6-P4N2 bonding modes, while the silver(I) complex [Ag2(O2CCF3)2 (µ-1)] contains the ligand 1 in an intermediate bonding mode in which the nitrogen donors are very weakly coordinated. The complexes [Pd2(OTf)2(µ-1)](OTf)2 and [Ag2(O2CCF3)2(µ-1)] react with 4,4′-bipyridine to give polymers [Pd2(µ-bipy)(µ-1)](OTf)4 and [Ag2(µ-bipy)(µ-1)](O2CCF3)2.