The influence of coordination modes and active sites of a 5-(triazol-1-yl) nicotinic ligand on the assembly of diverse MOFs.

Six new complexes based on 5-(triazol-1-yl)nicotinic acid (HL), namely [Cu(L)(HO)(OH)] (1), [Co(L)(HO)] (2), [Mn(L)(HO)] (3), {[Co(L)(HO)(DMF)(NO)]·(Cl)·DMF·2HO} (4), {[Cu(L)(O)]·CHOH·2.5HO} (5) and {[Co(L)(HO)]·2DMA·2HO} (6), were synthesized under hydro(solvo)thermal conditions. The L ligand in 1-6 reveals various coordination modes and forms diverse secondary building units (SBUs) in the final structures. Complex 1 shows a 2D layered structure with a rare (3,8)-connected topology based on tetranuclear [Cu(COO)(HO)(OH)N] SBUs. 2 and 3 are isostructural and display 2D 4-connected sql nets with a point symbol of (4·6). 4 and 5 have similar spatial 3D porous frameworks, which can be simplified as a (3,6)-connected 2-nodal net via dinuclear [Co(COO)(O)(NO)(N)] SBUs and [Cu(COO)(O)(N)] SBUs, respectively. 6 is a 3D porous framework constructed by dinuclear [Co(COO)(HO)(N)] motifs with a uninodal 4-connected qtz net. The magnetic properties and gas sorption behaviour of these complexes were investigated carefully, showing that 3 exhibits ferrimagnetic character and 4 demonstrates its effective storage capacity for CO as well as high selectivity for CO over CH under ambient conditions.