دورية
Synthesis, Characterization and Coordination Chemistry of Some Selenium-Containing Macrocyclic Schiff Bases
العنوان: | Synthesis, Characterization and Coordination Chemistry of Some Selenium-Containing Macrocyclic Schiff Bases |
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المؤلفون: | Panda, Arunashree, Menon, Saija C., Singh, Harkesh B., Morley, Christopher P., Bachman, Robert, Cocker, T. Matthew, Butcher, Ray J. |
المصدر: | European Journal of Inorganic Chemistry; March 2005, Vol. 2005 Issue: 6 p1114-1126, 13p |
مستخلص: | The condensation of bis(o-formylphenyl) selenide with 1,2-diaminoethane or 1,3-diaminopropane yielded the new macrocyclic ligands 1 and 2 in very good yields. Crystals of 1 are monoclinic, space group P21/c with a = 10.0648(10) Å, b = 37.390(4) Å, c = 8.0073(11) Å, Z = 4 and those of 2 are triclinic, space group P$\bar {1}$ with a = 7.200(3), b = 9.137(3), c = 12.780(6) Å, Z = 1. The coordination chemistry of 1 and 2 has been studied with the “soft” metal ion PdII and “hard” metal ions NiII and CoII. Reaction of [PdCl2(COD)] with 1 mol-equiv. of 1 or 2 in refluxing methanol and addition of NH4PF6 afforded the PdII complexes 5 and 6, respectively. Compound 5 is an unexpected partially hydrolyzed complex. It crystallizes in the tetragonal space group P41212 with a = 10.7737(10) Å, b = 10.7737(10) Å, c = 28.190(5) Å, Z = 4. The structure shows the PdII ion coordinated to a square-planar arrangement of two selenium and two nitrogen atoms. Reaction of NiCl2·6H2O with 1 or 2 and NH4PF6 yielded complexes 7 and 8, respectively. The assignment of octahedral geometries to [Ni(L)](PF6)2] (7: L = 1; 8: L = 2) follows from their paramagnetism [μeff = 3.23 (7), 1.81 (8) B.M.] and their UV/Vis spectra. This was also confirmed by single-crystal X-ray studies. The crystal structures of 7 and 8 showed a distorted octahedral nickel center coordinated by two selenium and four nitrogen atoms. 7: Monoclinic, space group P21/c; a = 9.979(2) Å, b = 18.901(4) Å, c = 19.333(4) Å; Z = 4. 8:Orthorhombic, space group Pna21; a = 20.277(5), b = 20.865(5), c = 9.416(2) Å; Z = 4. The cyclic voltammograms of 7 and 8 in MeCN solution show well-behaved quasi-reversible NiIII/NiII couples. The analogous CoII complex, [Co(1)](PF6)2] (9) also shows a quasi-reversible CoIII/CoII couple. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) |
قاعدة البيانات: | Supplemental Index |
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