Channel-containing structures generated from linear coordination polymer chains containing [formula omitted]-bidentate ligands and Cu–Cu dimetal units

Abstract

Four new one-dimensional coordination polymers containing the dimetal cluster Cu 2(OAc) 4 have been synthesized by reacting Cu(OAc) 2 ⋅ H 2O with two different N , N ′ -bidentate ligands. Reaction of the flexible ligand, 1,2-bis(4-pyridyl)ethane ( L 1), with the copper starting material produced two, co-crystallizing coordination polymers: catena-Poly[Cu 2(OAc) 4( L 1)] ⋅ 2H 2O ( 1) and catena-Poly[Cu 2(OAc) 4( L 1)]. In the solid state, 1 (monoclinic, C2/c, a = 24.9471 ( 17 ) Å , b = 13.3539 ( 9 ) Å , c = 8.8050 ( 6 ) Å , β = 93.6480 ( 10 ) ° , V = 2927.4 ( 3 ) Å 3 , Z = 4 ) features linear chains which are organized into layers. These layers stack along the crystallographic c-axis forming small hexagonal channels occupied by the solvent of crystallization. Compound 2 (triclinic, P-1, a = 7.6263 ( 6 ) Å , b = 8.5283 ( 6 ) Å , c = 9.8633 ( 6 ) Å , α = 74.1070 ( 10 ) ° , β = 68.2160 ( 10 ) ° , γ = 74.0090 ( 10 ) ° , V = 561.96 ( 7 ) Å 3 , Z = 1 ) also features linear chains of the coordination polymer, but differs from 1 in that the chains are packed so as to leave no significant channels. Reaction of the rigid ligand, 1,4-bis(4-pyridyl)buta-1,3-diyne ( L 2), with the copper starting material also afforded two co-crystallizing coordination polymers: catena-Poly[Cu 2(OAc) 4( L 2)] ( 3) and catena-Poly[Cu 2(OAc) 4( L 2)] ⋅ solvents ( 4). 3 (monoclinic, P2 1/m, a = 9.8065 ( 9 ) Å , b = 12.3793 ( 11 ) Å , c = 9.9408 ( 9 ) Å , β = 107.6009 ( 17 ) ° , V = 1150.29 ( 18 ) Å 3 , Z = 2 ), like 2, features linear chains and contains no significant solvent accessible void space. 4 (monoclinic, C2/c, a = 28.9810 ( 16 ) Å , b = 12.9301 ( 7 ) Å , c = 8.6954 ( 5 ) Å , β = 98.8010 ( 10 ) ° , V = 3220.0 ( 3 ) Å 3 , Z = 4 ) also consists of linear chains of the coordination polymer. However, the overall topology of 4 is identical to that of 1, with the generated hexagonal channels containing crystallographically unidentifiable solvents of crystallization. Compounds 1 and 2 and compounds 3 and 4 are pairs of polymorphic coordination polymers neglecting the solvents of crystallization in 1 and 4. The compounds, which represent four new examples of coordination polymers containing dimetal units, have been characterized by IR, elemental analysis, and thermogravimetric analysis in addition to X-ray crystallography.