ABSTRACT
A series of heterometallic magnesium diruthenium(ii,iii) carbonates, namely K{Mg(H2O)6}2[Ru2(CO3)4Cl2]·4H2O (1), K2[{Mg(H2O)4}2Ru2(CO3)4(H2O)Cl]Cl2·2H2O (2), K[Mg(H2O)5Ru2(CO3)4]·5H2O (3) and K[Mg(H2O)4Ru2(CO3)4]·H2O (4), were synthesized from the reaction of Ru2(CO3)4(3-) and Mg(2+) in aqueous solution. Compound 1 is composed of ionic crystals with the Ru2(CO3)4Cl2(5-) : Mg(H2O)6(2+) : K(+) ratio of 1 : 2 : 1. Compound 2 consists of two dimensional layer structures, in which each octahedral environment Mg(H2O)4(2+) bonds to two [Ru2(CO3)4(H2O)Cl](4-) units in a cis manner forming a neutral square-grid layer {Mg(H2O)4Ru2(CO3)4(H2O)Cl}n. For compound 3, one water molecule of each Mg(H2O)6(2+) is substituted by an oxygen atom of Ru2(CO3)4(3-) forming [Mg(H2O)5Ru2(CO3)4](-), and then the neighboring Ru2 dimers are linked together by the rest of the two oxygen atoms of carbonates to form a layer structure {Mg(H2O)5Ru2(CO3)4}n(n-). In compound 4, the neighboring squared-grid layers {Ru2(CO3)4}n(3n-), similar to those in compound 3, are linked by each octahedral environment Mg(H2O)4(2+) in a cis manner forming the three-dimensional network {Mg(H2O)4Ru2(CO3)4}n(n-). Compound 3 shows ferromagnetic coupling between Ru2 dimers, and a long-range ordering is observed below 3.8 K. Compound 4 displays a magnetic ordering below 3.5 K, and a systematic study of the size-dependent magnetic properties of compound 4 reveals that the coercivity of 4 has been improved with reduced sample particle size from the micrometer to the nanometer scale.
ABSTRACT
A sodion triethylenetetramine-bisdithiocarbamate (DTC-TETA) and its complexes with heavy metal ions were investigated by FTIR, UV, FAAS and elemental analysis, respectively. The FTIR spectrum of DTC-TETA showed strong absorption peaks at 1 461-1 388 cm(-1) and 1 174-996 cm(-1) which were attributed to partly double bonds of C-N and C-S, respectively. The UV spectrum of DTC-TETA had two absorption peaks at 265 and 290 nm, assigned to pi-pi* transition of N...C...S radical and nonbonding electron n-pi* transition of S...C...S radical to conjugated system, respectively. The elemental analysis results demonstrated that the mol ratio of C, H, N and S in DTC-TETA was about 2 : 4 : 1 : 1. As for UV spectrum of its complexes with Cu(II), Cd(II), Zn(II) and Ni(II), there were four new absorption peaks at 321, 310, 311 and 325 nm, respectively. Coupled to flow-injection, FAAS determination showed that the complexation performance of Cu2+, Cd2+, Ni2+ and Zn2+ complexes of DTC-TETA was better than that of sodium diethyldithiocarbamate (DDTC).
ABSTRACT
Characteristics of an aminated glucose and its complex with Cu (II) were investigated by FTIR, 1H-NMR and UV spectroscopy, respectively. Compared with glucose, the FTIR spectrum of an aminated glucose showed a moderate peak at 1 629-1 608 cm(-1) which was attributed to deltaNH vibration, suggesting that glucose reacted with ethylenediamine. The 1H-NMR spectrum of an aminated glucose demonstrated the signal of the C1 hydroxy proton and one of the amino proton at 4. 82-4. 79 ppm, illustrating that the amino of ethylenediamine was substituted for the hydroxy group of C1. As for UV spectra, an aminated glucose did not show absorbance in the ultraviolet region while its complex with Cu(II) had obvious absorption peak at about 236 nm. The complex ratio of the aminated glucose to Cu(II) was about 1 to 1 and the stability constant of its Cu(II) complex was 6.8 x 10(7) L x mol(-1).
ABSTRACT
Novel polynuclear Cu(II) complexes containing derivatives of 1,2,4-trizaole and pivalate ligands, [Cu(3)(mu(3)-OH)(mu-adetrz)(2)(piv)(5)(H(2)O)].6.5H(2)O (1) (adetrz = 4-amino-3,5-diethyl-1,2,4-triazole, piv = pivalate), [Cu(4)(mu(3)-OH)(2)(mu-atrz)(2)(mu-piv)(4)(piv)(2)].2MeOH.H(2)O (2) (atrz = 4-amino-1,2,4-triazole), [Cu(4)(mu(3)-OH)(2)(mu-tbtrz)(2)(mu-piv)(2)(piv)(4)].4H(2)O (3) (tbtrz = 4-tert-butyl-1,2,4-trizaole), and [Cu(4)(mu(3)-O)(2)(mu-admtrz)(4)(admtrz)(2)(mu-piv)(2)(piv)(2)].2[Cu(2)(mu-H(2)O)(mu-admtrz)(piv)(4)].13H(2)O [4 = 4a.2(4b).13H(2)O; admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole], have been prepared and structurally characterized. 1 is an asymmetrical triangular complex containing a [Cu(3)(mu(3)-OH)] core with two Cu---Cu edges spanned by bridging adetrz ligands. 2, 3, and 4a are novel tetranuclear compounds containing a [Cu(4)(mu(3)-O)(2)] or [Cu(4)(mu(3)-OH)(2)] core with Cu---Cu edges spanned by bridging 1,2,4-triazole or pivalate ligands. 4b is a dinuclear compound with one admtrz and one water bridge, and it is the first dinuclear Cu(II) triazole complex with one bridging water molecule. 1 is one of few reported triangular Cu(II) complexes with derivatives of 1,2,4-triazole, while 2, 3, and 4a are the first group of the nonlinear tetranuclear Cu(II) compounds with derivatives of 1,2,4-triazole. Variable-temperature magnetic susceptibility studies on the powder samples of 1-3 reveal the overall antiferromagnetic coupling between Cu(II) ions with J values of -55.6 to -12.8 cm(-1) (1), -216.4 to 0 cm(-1) (2), and -259.8 to 4.8 cm(-1) (3).
