Novel Cadmium( II ) Adipate Coordination Polymers with Structural Transformation via Oxalate Ligand: Syntheses, Structures and Fluorescence Properties

Two novel cadmium adipate coordination polymers [Cd{O 2 C(CH 2 ) 4 CO 2 }{1,10‐phen}] n ( 1 ) and [Cd 2 (C 2 O 4 ){O 2 C(CH 2 ) 4 CO 2 (OH 2 ) 2 }{2,2′‐bipy}]·H 2 O ( 2 ) [adipic acid = HO 2 C(CH 2 ) 4 CO 2 H] have been hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction. Crystallographic data for 1 : monoclinic, C 2/ c , a = 16.186(3) Å, b = 15.487(3) Å, c = 14.052(3) Å, β = 112.73(3)°, Z = 8. Crystal data for 2 : monoclinic, Cc , a = 23.448(5) Å, b = 11.826(2) Å, c = 8.3163(17) Å, β = 99.08(3)°, Z = 4. The structural analysis reveals that 1 forms a novel one‐dimensional chain in which the binuclear Cd centers are linked by adipate anions. Compound 2 is the first example in which both a 2,2′‐bipy ligand and an oxalate group are found in the {M/adipate} system. Compound 2 possesses one‐dimensional sine‐ or cosine‐type chains, which are alternately connected together by the oxalate group to form a three‐dimensional framework. The structural determination reveals that the introduction of the oxalate ligand causes the dimensional transformation of the compounds. Compounds 1 and 2 show strong fluorescent properties at room temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)