Lewis base-directed assembly of two cobalt-based metal-organic frameworks

The employment of different Lewis bases pyridine and 3,5-DMpy under solvothermal conditions gave rise to two isostructural three-dimensional metal-organic frameworks: Co2(py)2(L)(DMA)2 (1) and Co2(L)(DMA)4 (2) (H4L = 5-(3,5-dicarboxybenzoylamino)-isophthalic acid, py = pyridine, DMA = N,N-dimethylacetamide, 3,5-DMpy = 3,5-dimethylpyridine). Single-crystal X-ray analysis has shown that 1 furnishes two different types of one-dimensional channels occupied by bridging DMA and terminal pyridine molecules. Changing pyridine to 3,5-DMpy in the assembly procedure affords 2, in which the channels are filled with bridging and terminal DMA molecules exclusively.