Synthesis and Structural Diversity of Main Group Metal Coordination Complexes Constructed from V‐Shape Bis(3‐methyl‐1H‐pyrazole‐4‐carboxylic acid)alkane Ligands

Abstract

Reaction of H2L1/H2L2/H2L3 with corresponding main group metal salts generated five complexes, [Mg(L1)(phen)(H2O)3]⋅5H2O (1, mononuclear), [Sr(CH3OH)(L1)2Sr(H2O)2]2n⋅nH2O (2, 2D), [Ba(L2)(H2O)3]n (3, 2D), [Pb(L2)(2,2′‐bpy)]2n⋅9nH2O (4, 1D) and [Pb(L3)(phen)]2⋅2DMF (5, dinuclear) (H2L1=1,1'‐methylenebis(5‐methyl‐pyrazole‐4‐carboxylic acid, H2L2 = 2'‐methylenebis(3‐methyl‐pyrazole‐4‐carboxylic acid, H2L3=1,1'‐methylenebis(3‐methyl‐pyrazole‐4‐carboxylic acid; 2,2’‐bpy=2,2′‐bpyridine and phen=1,10‐phenanthroline). In the zwitterionic complex 1, a loop‐loop water‐water hydrogen bonded chain presented in the 3D supramolecular network, which was constructed by π⋅⋅⋅π interactions and hydrogen bonds. In CPs 2 and 3, the 1D inorganic M–O–M connectivity was built from Sr2O16 and BaO9 polyhedra, respectively. The similar 24‐membered Pb2(L2)2/Pb2(L3)2 macrocycle occurred in both 1D polymer 4 and dinuclear complex 5, with two 2,2’‐bpy molecules located inside or two phen molecules outside each macrocycle respectively. The thermal and photoluminescent properties of 1–5 in the solid state have also been investigated.