Crystal Engineering of the Coordination Architecture of Metal Polycarboxylate Complexes by Hydrothermal Synthesis: Assembly and Characterization of Four Novel Cadmium Polycarboxylate Coordination Polymers Based on Mixed Ligands

Four novel compounds, [Cd(tp)(bpp)] n ( 1 ), [Cd(tp)(bpy)] n ( 2 ), [{Cd 4 (bpa) 4 (bpy) 6 }·(bpy) 0.5 ·7H 2 O] n ( 3 ) and [Cd 2 {(Htp)(tp) 1.5 }(bpe)] n ( 4 ) [tp = terephthalate, bpp = 1,3‐bis(4‐pyridyl)propane, bpy = 4,4′‐ bipyridine, bpa = 4,4′‐biphenyldicarboxylate, bpe = 1,2‐bis(4‐pyridyl)ethane], of cadmium( II ) polycarboxylate coordination polymers based on mixed ligands were obtained by a hydrothermal method. Complex 1 (C 21 H 18 CdN 2 O 4 ) crystallizes in the orthorhombic Pbca space group [ a = 11.9401(0) Å, b = 16.8148(3) Å, c = 20.2743(3) Å, and Z = 8]. Complex 2 (C 18 H 12 CdN 2 O 4 ) belongs to the monoclinic C2 / m space group [ a = 20.299(3) Å, b = 10.720(1) Å, c = 11.764(2) Å, β = 110.944(2)°, and Z = 6]. Complex 3 (C 121 H 98 Cd 4 N 13 O 23 ) belongs to the monoclinic P 2 1 / c space group [ a = 23.2208(0) Å, b = 11.8103(1) Å, c = 45.4670(6) Å, β = 104.516(1)°, and Z = 4]. Complex 4 (C 32 H 23 Cd 2 N 2 O 10 ) belongs to the monoclinic P 2 1 / n space group [ a = 6.9896(1) Å, b = 22.6294(1) Å, c = 19.7738(3)Å, β = 99.380(1)°, and Z = 4].The Cd II centers in the four compounds are bridged by mixed polycarboxylate ligands with bpy and related species to form the twofold parallel interpenetration topology of an undulating 2D 4 4 net for 1 , a twofold interpenetration topology of a 3D α‐Po net for 2 , a fourfold interpenetration topology of a 3D 5‐connected borazone 4 6 6 4 net for 3 and an interesting 3D spiral pipe‐like structure with a bolt for 4 . These four compounds exhibit strong fluorescent emissions at 549 and 582 nm ( λ ex = 532 nm) for 1 , 493 nm ( λ ex = 360 nm) for 2 , 413 and 424 nm ( λ ex = 315 nm) for 3 and 350 nm ( λ ex = 220 nm) for 4 in the solid state at room temperature. These are novel structural topologies and could be significant in the field of photoactive materials. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)