COPPER(II) COORDINATION COMPOUNDS WITH BIS(IMIDAZOL-2-YL)METHYLAMINE AND BIS(IMIDAZOL-2-YL)METHYLAMINOMETHANE IN RELATION TO BIS(IMIDAZOL-2-YL)METHYLAMINE-MODIFIED POLY(GLYCIDYL METHACRYLATE) POLYMERS AND OTHER BIS(IMIDAZOL-2-YL)-CONTAINING LIGANDS

摘要

The synthesis, spectroscopy, and structure of three Cu(II) coordination compounds of the ligands bis(imidazol-2-yl)methylaminomethane (bimam) and bis(imidazol-2-yl)methylamine (bima) are described. The ligands bimam and bima both coordinate to Cu(II) ions in a didentate fashion. In all three complexes the copper(II) ions are coordinated in a distorted octahedral geometry. In [Cu(Hbimam)Cl-3](2)(H2O)(2) and [Cu(Hbima)Cl-3](2)(H2O)(2) each Cu(lI) ion is coordinated by two imidazole nitrogens and four chloride anions. The two mononuclear units are connected by two asymmetric chloride bridges. In [Cu(Hbimam)(2)Cl-2]Cl-2(H2O)(2) the Cu(II) ion is coordinated by four imidazole nitrogens and two chloride anions. In the present complexes the amine nitrogen donor of the ligand is hydronated and not coordinated to the Cu(II) ion. [(De)hydronated is the recommended IUPAC expression to indicate loss/addition of H+.] In all three complexes strong hydrogen bonding is observed between the amine nitrogen donor(s) and the axial coordinated chloride(s). X-ray crystallographic parameters for the copper complexes are as follows: [Cu(Hbimam)Cl-3](2)(H2O)(2), monoclinic, space group P2(1)/c, Z = 4, a = 12.6259(8) Angstrom, b = 8.3452(4) Angstrom, c = 15.9280(8) Angstrom, beta = 124.458(5)degrees, V = 1383.80(15) Angstrom(3), R = 0.037, R(w) = 0.047 for 2792 reflections with I > 2.5 sigma(I); Cu-N 2.0271(18) and 1.992(2) Angstrom, Cu-Cl 2.2705(8), 2.2854(8) 2.9266(11), and 3.2212(12) Angstrom. [Cu(Hbimam)(2)Cl-2]Cl-2(H2O)(2), monoclinic, space group P2(1)/c, Z = 4, a = 7.6507(5) Angstrom, b = 21.4241(13) Angstrom, c = 14.8152(12) Angstrom, beta 93.285(6)degrees, V = 2424.4(3) Angstrom(3), R = 0.0289 for 4781 reflections with I > 2 sigma(I), wR2 = 0.0716 for 5534 reflections; Cu-N 2.0201(15), 1.9970(15), 2.0082(15), and 2.0102(15) Angstrom; Cu-Cl2.9019(5) and 2.9064(5) Angstrom. [Cu(Hbima)Cl-3](2)(H2O)(2), monoclinic space group P2(1)/c, Z = 4, a = 12.549(2) Angstrom, b = 8.345(2) Angstrom, c = 16.630(4) Angstrom, beta 126.22(2)degrees, V = 1405.0(6) Angstrom(3), R = 0.077 for 1774 reflections with I > 2 sigma(I), wR2 = 0.190 for 3208 reflections; Cu-N 1.997(6) and 2.018(6) Angstrom; Cu-Cl2.284(2), 2.286(2), 2.970(3), and 2.9843(3) Angstrom. The ligand bimam was also immobilized onto a solid support, poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate) (p(GMT)), yielding a very Cu(II)-selective chelating ion-exchange resin pGMT-bimam with high uptake capacity. The resin retains its high uptake capacity for Cu(II) even in the presence of 1,2-diaminoethane, 1,3-diaminopropane and 1,4-diaminobutane as competing ligands in solution. When tartrate is used as a competitor, even a positive effect on the Cu(II) uptake is observed. For Na(2)H(2)edta as competitor in solution, both a pH effect and a concentration effect were noticed; i.e., with increasing pH and increasing molar ratios (Na(2)H(2)edta: Cu(II)) the Cu(II) uptake of the ion exchanger decreases rapidly. Comparative spectroscopic studies of the coordination compounds with bimam and bima in their relationship to chelation of Cu(lI) ions on the ion-exchange resin pGMT-bimam, have shown that on the resin only 1:2 (Cu(II):bimam) complexes are formed. [References: 42]