The macrocyclic ligand(L) and its dinuclear copper(Ⅱ) and zinc(Ⅱ) complexes have been synthesized. The crystal structure of [Cu 2L(Him) 2](ClO 4) 4·2H 2O has been determined by single crystal X ray diffraction....The macrocyclic ligand(L) and its dinuclear copper(Ⅱ) and zinc(Ⅱ) complexes have been synthesized. The crystal structure of [Cu 2L(Him) 2](ClO 4) 4·2H 2O has been determined by single crystal X ray diffraction. It crystallizes in a monoclinic system, the space group P2 1/c , a =0.951 2(2) nm, b =2.010 4(4) nm, c =1.202 5(2) nm, β =98.89(3)°, V =2.271 9(8) nm 3, Z=2, D c=1.599 Mg/m 3 , F (000) = 876 , R =0.059 1, wR =0.173 3, GOF(F)=1.009. The copper(Ⅱ) atom is five coordinated with four nitrogen atoms of the macrocyclic ligand and one nitrogen atom of imidazole. The stepwise stability constants of the 1∶1 and 2∶1 molar ratios of Cu to L and Zn to L complexes were determined by potentiometric titration in KCl supporting electrolyte(0.100 mol/L) at 25 ℃. The results indicated that zinc(Ⅱ) ion can form hydroxide bridged dinuclear complex [Zn 2(OH)L] 3+ , while the copper(Ⅱ) ion can only form dinuclear complex 3+ with macrocyclic ligand.展开更多
The formation constants of Co￣(2+), Ni￣(2+), Cu￣(2+) and Zn￣(2+) complexes with humic acid (HA) and fulvicacid (FA) in red soil were determined by the potentiometric titration method. The constants as a functionof...The formation constants of Co￣(2+), Ni￣(2+), Cu￣(2+) and Zn￣(2+) complexes with humic acid (HA) and fulvicacid (FA) in red soil were determined by the potentiometric titration method. The constants as a functionof composition of the complexation solutions were obtained by two graphical approaches respectively Theformation constants decreased with increasing concentration of metal in the solution. The results provideunambiguous evidence for the heterogeneity of the function groups of humic substances. The formationconstants of FA were much smaller than those of HA, and the formation constants of Cu￣(2+) were muchgreater than those of Co￣(2+) , Ni￣(2+) and Zn￣(2+) . The potentiometric titration method for determining formationconstants are also discussed in the article.展开更多
文摘The macrocyclic ligand(L) and its dinuclear copper(Ⅱ) and zinc(Ⅱ) complexes have been synthesized. The crystal structure of [Cu 2L(Him) 2](ClO 4) 4·2H 2O has been determined by single crystal X ray diffraction. It crystallizes in a monoclinic system, the space group P2 1/c , a =0.951 2(2) nm, b =2.010 4(4) nm, c =1.202 5(2) nm, β =98.89(3)°, V =2.271 9(8) nm 3, Z=2, D c=1.599 Mg/m 3 , F (000) = 876 , R =0.059 1, wR =0.173 3, GOF(F)=1.009. The copper(Ⅱ) atom is five coordinated with four nitrogen atoms of the macrocyclic ligand and one nitrogen atom of imidazole. The stepwise stability constants of the 1∶1 and 2∶1 molar ratios of Cu to L and Zn to L complexes were determined by potentiometric titration in KCl supporting electrolyte(0.100 mol/L) at 25 ℃. The results indicated that zinc(Ⅱ) ion can form hydroxide bridged dinuclear complex [Zn 2(OH)L] 3+ , while the copper(Ⅱ) ion can only form dinuclear complex 3+ with macrocyclic ligand.
文摘The formation constants of Co￣(2+), Ni￣(2+), Cu￣(2+) and Zn￣(2+) complexes with humic acid (HA) and fulvicacid (FA) in red soil were determined by the potentiometric titration method. The constants as a functionof composition of the complexation solutions were obtained by two graphical approaches respectively Theformation constants decreased with increasing concentration of metal in the solution. The results provideunambiguous evidence for the heterogeneity of the function groups of humic substances. The formationconstants of FA were much smaller than those of HA, and the formation constants of Cu￣(2+) were muchgreater than those of Co￣(2+) , Ni￣(2+) and Zn￣(2+) . The potentiometric titration method for determining formationconstants are also discussed in the article.
