Synthesis and Crystal Structure of an Expanded Square Grid Metal Organic Material, [Cu(L1)(DMF)]n•(2.64 DMF)

A new square grid metal organic material, [Cu(L1)(DMF)](n)center dot(2.64 DMF) (1; L1 = N-(4-carboxyphenyl)-trimellitimide), has been prepared by solvothermal reaction of Cu(NO3)(2)center dot 2.5H(2)O, H(2)L1, and caffeine in N,N-dimethylformamide (DMF). The title compound crystallizes in the monoclinic crystal system, space group C2/c, with a = 18.5176 (6) , b = 23.7473 (7) , c = 18.1998 (5) , beta = 107.527 (2)A degrees, and V = 7631.7 (4) (3). The undulating sheets, formed by linking of Cu-2(mu(2)-CO2)(4) square paddlewheel nodes by the angular L1, stack to form large square channels of approximately 11.9 x 11.9 (2) running along the c axis. The geometry and conformation of the linker result in slight distortion of the grids. Further, the 147A degrees bend angle between coordinating moieties of L1 is amenable to forming a diverse array of paddlewheel-based supramolecular isomers.