The reaction of cobalt(II) chloride with 2 hydroxypyridine (Hhp) and lithium pivalate in acetonitrile affords the 1D polymer [Li 3 CoCl(μ Piv)(μ 3 Piv) 2 (μ 3 ,η 2 Piv)(μ Hhp) 2 (η 1 HPiv)] n , in which the repeating units are linked by bridging pyridone molecules. The reaction of cobalt nitrate hexahydrate with 2 hydroxy 6 methylpyridine (Hmhp) in the presence of the deproto nating agent (Et 3 N) resulted in the crystallization of the 1D polymer of the composition [Li 2 Co 7 (μ 3 OH) 2 (μ 3 Piv) 3 (μ Piv) 2 (μ 3 ,η 2 mhp) 5 (μ,η 2 mhp) 2 (μ 3 mhp)(μ,η 2 NO 3 )•2MeCN] n , in which the bulky metal fragments {Li 2 Co 7 (OH) 2 (Piv) 5 )(mhp) 8 } are linked together through the lithium atoms by chelate bridging nitrate anions. The resulting 1D polymers were charac terized by X ray diffraction, and their magnetic properties were investigated.
The reaction of copper nitrate Cu(NO 3 ) 2 •3H 2 O with potassium salt of 1,1 cyclohex anediacetic acid (H 2 CHDAA) in an EtOH-toluene mixture affords the polymeric com plex {[(EtOH) 2 Cu 2 (CHDAA) 2 ]•EtOH} n (1). The addition of pyridine to the Cu(NO 3 ) 2 •3H 2 O-K 2 CHDAA reaction system in an EtOH-MeCN mixture results in the isolation of the unusual octadecanuclear heterometallic cluster [K 2 (η 1 H 2 O) 6 (η 1 py) 8 Cu 16 (η 1 OH) 2 (μ 4 CHDAA) 16 ]•EtOH•MeCN•3H 2 O (2). In complex 2, the hexadecanuclear metal carboxylate dianion (η 1 H 2 O) 6 (η 1 py) 8 Cu 16 (η 1 OH) 2 (μ 4 CHDAA) 16 acts as the metal con taining macropolycyclic ligand. The newly synthesized compounds 1 and 2 were characterized by X ray diffraction and EPR.Dicarboxylic acids act as polydentate bridging ligands and often play the structuring role in the formation of coordination polymers. 1-3 However, in some cases it is impossible to reliably determine the structures of these compounds and, as a consequence, to interpret with cer tainty their properties because of their poor solubility. For example, according to the published data, only four ade quately characterized complexes with 1,1 cyclohexanedi acetate anions and transition metal atoms have been iso lated, two of which have an island structure, 4,5 whereas two other complexes are polymers. 6 At the same time, the geometric features of these dian ions and their conformational flexibility are such that these organic units can be used in the design of unusual archi tectures with transition metal atoms, including cyclic sys tems, analogous to the known "rings" with chromium and iron atoms bound to monocarboxylic acid anions. 7,8 Evi dently, this can lead to the formation of more complex architectures of polycyclic metal containing cores. Hence, these systems can be considered as promising metal con taining "crowns" suitable for the extraction of other metal ions, for example, of alkali metal ions, from solution.In the present study, we investigated the possibility of the formation of polynuclear complexes with different geometries starting from the copper(II) nitrate-potassium 1,1 cyclohexanediacetate (K 2 CHDAA) system by the self assembly in solution and also studied the effect of the addition of pyridine on the formation of polynuclear structures.
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