Solvent-Dependent Formations of Supramolecular Isomers and a Single-Crystal to Single-Crystal Transformation from a Cyclic Dimer Complex to a One-Dimensional Coordination Polymer

摘要

Solvent-dependent supramolecular isomers of a tripodal ligand incorporating two para-pyridylmethyl arms, N-naphthylmetyl-N,N-bis(4-pyridylmethyl)amine (L), are reported. A combination of L and copper(II) hexafluoroacetylacetonate, Cu(hfac)(2), in methanol afforded a cyclic dimer complex [Cu-2(L)(2)(hfac)(4)]center dot CH3OH (1). In chloroform/methanol, the same reaction furnished an infinite one-dimensional (1D) complex {[Cu-2(L)(2)(hfac)(4)]center dot 2CHCl(3)}(n) (2). When the cyclic dimer 1 was immersed in chloroform/ether, its transformation to the 1D coordination polymer 2 was observed in an single-crystal to single-crystal manner. In silver(I) triflate complexations, three supramolecular isomers (3-5) were isolated. In chloroform/methanol, a multichannel-type three-dimensional (3D) coordination polymer {[Ag(L)](CF3SO3)center dot 0.5CHCl(3)}(n) (3) was isolated. In isomer 3, the Ag atom link L ligands alternately to form a helix, and these are linked by Ag-Ag contacts to generate an etb topology. In acetonitrile/methanol, a multichannel-type 3D coordination polymer {[Ag(L)](CF3SO3)center dot CH3CN}(n) (4) was isolated. In isomer 4, six Ag atoms and six L ligands form an Ag6L6 hexagonal unit, and these are linked via Ag-Ag contacts, resulting in a pcu-h topology. In toluene/methanol/ acetonitrile, a cross-linked ladder-type coordination polymer {[Ag-4(L)(4)(CF3SO3)(2)](CF3SO3)(2)center dot 3(toluene)}(n) (5) was obtained. The isomer 5 is composed of two types of ladders crossed showing a new topology. Considering the formation of the (pi-pi)-(Ag-Ag)-(pi-pi) unit in 3-5, it is suggested that the anion-solvent interaction could be a major reason.