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The syntheses, structures and properties of the complexes [CdBr2(L)2·4H2O]n [L = 2,6-dimethyl-3,5-dicyano-4-(4-pyridyl)-1,4-dihydropyridine], 1 and [Cd(SCN)2(L)2(H2O)]n, 2, are reported. In polymeric complexes 1 — 2, the L ligands bridge the metal centers through the pyrimidyl and cyano nitrogen atoms forming 1-D double-stranded chain and zigzag chain, respectively. The L ligands in complex 1 act as κ1, κ1-bidentate bridging ligand, whereas the L ligands in complex 2 act as κ1-monodentae and κ1, κ1-bidentate bridging ligand. The molecules of these complexes are interlinked through various weak interactions that form the packed structure. All the complexes exhibit emissions which may be tentatively assigned as intraligand (IL) ππ* transitions.

BACKGROUND: Biosorption of heavy metals from aqueous solution by modified activated carbon with Phanerochaete chrysosporium immobilised in Ca-alginate beads was investigated using a batch system and comparison of linear and nonlinear methods. RESULTS: The amount of Cu(II), Zn(II) and Pb(II) ion sorption by the beads was as follows: activated carbon with P. chrysosporium immobilised in Ca-alginate beads (ACFCA) (193.4, 181.8, 136.6 mg g−1) > activated carbon immobilised in Ca-alginate beads (ACCA) (174.8, 162.0, 130.7 mg g−1) > P. chrysosporium (F) (148.8, 125.6, 120.4 mg g−1) > activated carbon (AC) (138.8, 112.3, 109.3 mg g−1) > plain Ca-alginate beads (PCA) (125.4, 105.2, 98.2 mg g−1). The widely used Langmuir and Freundlich isotherm models were utilised to describe the biosorption equilibrium process. CONCLUSION: The results of this study suggest that the immobilisation of modified activated carbon with P. chrysosporium in Ca-alginate beads is suitable for a batch system. The isotherm parameters were estimated using linear and nonlinear regression analyses. The surface charge density of the biosorbents varied with the pH of the medium; the maximum biosorption of heavy metal ions on the biosorbents was obtained when the pH was between 5.6 and 7.4. Copyright © 2008 Society of Chemical Industry