This paper reports the biomimetic catalytic properties of new Schiff base mononuclear complexes MH 2L｛M = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L=bis[ N,N′-ethylene-2,2′-(phenylmethylene)bis(3...This paper reports the biomimetic catalytic properties of new Schiff base mononuclear complexes MH 2L｛M = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L=bis[ N,N′-ethylene-2,2′-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)]｝and dinuclear complexes MnML[M=Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)] for studying the monooxygenation of cyclohexane with PhIO and magnetic properties of the dinuclear complexes. The investigation of the magnetic properties(4—300 K) of the dinuclear complexes revealed that their antiferromagnetic spin exchange with J varied from -10.49 to -0.482 cm -1 except MnZnL, and antiferromagnetic spin exchange decreased in the order: Mn(Ⅱ)-Cu(Ⅱ)>Mn(Ⅱ)-Ni(Ⅱ)>Mn(Ⅱ)-Mn(Ⅱ)>Mn(Ⅱ)- Fe(Ⅲ)>Mn(Ⅱ)-Co(Ⅱ)>Mn(Ⅱ)-Cr(Ⅲ). The yield determination of monooxygenation of cyclohexane indicated that the catalytic reactivity of the dinuclear complex was better than that of the corresponding mononuclear complex, so we supposed that there was some cooperative action between the two metals in these dinuclear complexes. It was found that the cooperation lay in the decreasing order: Mn-{Fe>}Mn-Cr>Mn-Cu>Mn-Mn>Mn-Co>Mn-Ni>Mn-Zn. It seems that this cooperation increased with the increase of the number of unpaired d electrons and the magnetic exchange between the two metals in these dinuclear complexes.展开更多
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
文摘This paper reports the biomimetic catalytic properties of new Schiff base mononuclear complexes MH 2L｛M = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L=bis[ N,N′-ethylene-2,2′-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)]｝and dinuclear complexes MnML[M=Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)] for studying the monooxygenation of cyclohexane with PhIO and magnetic properties of the dinuclear complexes. The investigation of the magnetic properties(4—300 K) of the dinuclear complexes revealed that their antiferromagnetic spin exchange with J varied from -10.49 to -0.482 cm -1 except MnZnL, and antiferromagnetic spin exchange decreased in the order: Mn(Ⅱ)-Cu(Ⅱ)>Mn(Ⅱ)-Ni(Ⅱ)>Mn(Ⅱ)-Mn(Ⅱ)>Mn(Ⅱ)- Fe(Ⅲ)>Mn(Ⅱ)-Co(Ⅱ)>Mn(Ⅱ)-Cr(Ⅲ). The yield determination of monooxygenation of cyclohexane indicated that the catalytic reactivity of the dinuclear complex was better than that of the corresponding mononuclear complex, so we supposed that there was some cooperative action between the two metals in these dinuclear complexes. It was found that the cooperation lay in the decreasing order: Mn-{Fe>}Mn-Cr>Mn-Cu>Mn-Mn>Mn-Co>Mn-Ni>Mn-Zn. It seems that this cooperation increased with the increase of the number of unpaired d electrons and the magnetic exchange between the two metals in these dinuclear complexes.
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.
