Synthesis and crystal structures of novel one-dimensional polymers, [{M(bpen)X}∞][M = CuI, X = PF6–; M = AgI, X = ClO4–; bpen =trans-1,2-bis(2-pyridyl)ethylene] and [{Cu(bpen)(CO)(CH3CN)(PF6)}∞]
Abstract
The new polymeric compounds [{M(bpen)X}∞][M = CuI, X = PF6–, 1; M = AgI, X = ClO4–, 2; bpen =trans-1,2-bis(2-pyridyl)ethylene] and [{Cu(bpen)(CO)(CH3CN)(PF6)}∞]3 have been synthesised and their structures determined by X-ray crystallography: 1, monoclinic, space group P21/n, a= 13.653(8), b= 9.288(3), c= 11.232(3)Å, β= 96.89(3)° and Z= 4; 2, triclinic, space group P, a= 7.569(1), b= 13.253(5), c= 6.757(1)Å, α= 92.24(3), β= 104.05(1), γ= 78.41(3)° and Z= 2; 3, triclinic, space group P, a= 9.882(8), b= 12.126(9), c= 8.173(8)Å, α= 93.33(9), β= 102.10(9), γ= 106.90(7)° and Z= 2. The complexes show an infinite-chain structure of macrocations with non-interacting PF6– or ClO4– anions. Compounds 1 and 2 are unique polymers having a linear co-ordination geometry, characteristic of d10 metals. They differ in the mode of polymerization, being of rectangular and triangular wave chain types, respectively. A non-coplanar structure between the pyridyl and olefinic groups of the co-ordinated bpen is recognized, indicative of the importance of intermolecular interaction in crystal packing. Compound 3 has a tetrahedral form of copper(I) as a repeating unit, involving a single CO molecule, which exhibits a short CO distance [1.104(6)Å] irrespective of the normal ν(CO) value (2088 cm–1). Proton NMR spectra of the copper(I)–bpen systems demonstrate that the solution species has a dimeric structure having two bridging bpen, where the olefinic moiety is co-ordinated to copper(I), dissimilar to the co-ordination mode of 1. A difference in chemical shifts between the PF6– and ClO4– salts is observed, indicative of the interaction of ClO4– with copper(I). The polymeric complex is predominantly obtained from the PF6– salt. The formation and the structure of CO or C2H4 adducts in solution have also been examined by 1H NMR spectroscopy.