Polymeric and tetranuclear silver(I) chains encapsulated by a scorpion-like ligand.: Synthesis and structures of [Ag2(tren(mim)3)]n (NO3)2n•nH2O and [Ag4(tren(mim)3)2]-(CF3SO3)4•2H2O (tren(mim)3 = tris{2-[2-(1-methyl)imidazolyl]-methyliminoethyl}amine)

Two compounds, [Ag-2(tren(mim)(3))](n)(NO3)(2n).n H2O (1) and [Ag-4(tren(mim)(3))(2)](CF3SO3)(4). 2H(2)O (2), were obtained by self-assembly of AgX (X = NO3-, F3CSO3-) with tren(mim), (tren(mim), = tris{2-[2-(1-methyl)imidazolyl]methyliminoethyl}amine). The crystal structures of 1 and 2 have been determined by X-ray diffraction analysis. In I, three arms of the ligand, which can be described as a scorpion-like ligand, function in both the usual bidentate chelate fashion and an unprecedented bidentate bridging mode in coordination to Ag(I) atoms; the ligands wrap the infinite Ag(I) wire with the adjacent Ag . . . Ag separation of approximately 3.0 Angstrom, indicating weak metal-metal interaction, to furnish cationic helical chains. The ligand in 2 behaves in two different coordination fashions in comparison to the ligand in 1. Two ligands encapsulate four,Ag(I) atoms in an interlocking fashion. A pair of the tetranuclear cations related by an inversion center is connected to form an octanuclear cation through a ligand-unsupported metallic interaction between two Ag(I) atoms being separated at 3.117(2) Angstrom and belonging to different tetranuclear cations. The H-1 NMR spectra of 1 and 2 in solution are virtually identical, indicating that 1 and 2 have similar structures in solution. (C) 2000 Elsevier Science B.V. All rights reserved.