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 [Cu2 (L)3 (H2 O)(OH)]n (1), [Co(L)2 (H2 O)2 ]n (2), [Mn(L)2 (H2 O)2 ]n (3), {[Co(L)(H2 O)0.5 (DMF)0.5 (NO3 )0.5 ]·(Cl)0.5 ·DMF·2H2 O}n (4), {[Cu(L)(O)0.5 ]·CH3 OH·2.5H2 O}n (5) and {[Co2 (L)4 (H2 O)]·2DMA·2H2 O}n (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 [Cu4 (COO)6 (H2 O)2 (OH)2 N6 ] SBUs. 2 and 3 are isostructural and display 2D 4-connected sql nets with a point symbol of (44 ·62 ). 4 and 5 have similar spatial 3D porous frameworks, which can be simplified as a (3,6)-connected 2-nodal net via dinuclear [Co2 (COO)2 (O)2 (NO3 )(N)4 ] SBUs and [Cu2 (COO)2 (O)(N)4 ] SBUs, respectively. 6 is a 3D porous framework constructed by dinuclear [Co2 (COO)4 (H2 O)(N)4 ] 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 CO2 as well as high selectivity for CO2 over CH4 under ambient conditions.