Coordination driven or/and H-bonded Cu(II)–N,N-dialkylisonicotinamide frameworks

Reactions of N,N-diisopropylisonicotinamide (L) with anhydrous CuCl2, CuBr2 and Cu(ClO4)2·6H2O yielded: (a) an ionic product with the molecular composition of [CuL2(H2O)4]·2[CuLCl3] 1; (b) a coordination polymer [CuL2Br2]n2 and (c) a mononuclear complex [CuL4(C3H8O)2]·(ClO4)2] 3, respectively. Similarly, the reaction of N,N-diisobutylisonicotinamide (L′) with Cu(NO3)2·3H2O yielded a coordination polymer [{CuL′2(H2O)2}(NO3)2]n4. The ligands L and L′ coordinate in a monodentate fashion through the pyridine nitrogen atom to the metal centers in complexes 1 and 3. However, complexes 2 and 4 are coordination polymers in which the corresponding ligands (L and L′) act as bridging bidentate between metal centers to form 1D double chains. All the four complexes form networks through coordination polymerization and/or hydrogen bonding.

Graphical abstractM(II)–N,N-dialkylisonicotinamide complexes self assemble into 1D and 2D networks using H-bonding and coordination polymerization.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► M(II)–N,N-dialkylisonicotinamide complexes self assemble into 1D and 2D networks. ► N,N-dialkylisonicotinamides act as bidentate bridges to form coordination polymers. ► Increase in dimensionality from 1D to 2D by involving ionic moieties in H-bonding.