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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Dinuclear metal(II)-acetato complexes based on bicompartmental 4-chlorophenolate: syntheses, structures, magnetic properties, DNA interactions and phosphodiester hydrolysis
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Dinuclear metal(II)-acetato complexes based on bicompartmental 4-chlorophenolate: syntheses, structures, magnetic properties, DNA interactions and phosphodiester hydrolysis

机译：基于双室4-氯酚盐的双核金属（II）-乙酰基配合物：合成，结构，磁性，DNA相互作用和磷酸二酯水解

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A series of dinuclear metal(II)-acetato complexes: [Ni-2(mu-(LO)-O-Cl)(mu(2)-OAc)(2)](PF6)center dot 3H(2)O (1), [Ni-2(mu-(LO)-O-Cl)(mu(2)-OAc)(2)](ClO4)center dot CH3COCH3 (2), [Cu-2(mu-(LO)-O-Cl)(mu(2)-OAc)(ClO4)](ClO4) (3), [Cu-2(mu-(LO)-O-Cl)(OAc)(2)](PF6)center dot H2O (4), [Zn-2(mu-(LO)-O-Cl)(mu(2)-OAc)(2)](PF6) (5) and [Mn-2(L-Cl-O)(mu(2)-OAc)(2)](ClO4)center dot H2O (6), where (LO-)-O-Cl = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenolate, were synthesized. The complexes were structurally characterized by spectroscopic techniques and single crystal X-ray crystallography. Six-coordinate geometries with doubly bridged acetato ligands were found in Ni(II), Zn(II) and Mn(II) complexes 1, 2, 5 and 6, whereas with Cu(II) complexes a five-coordinate species was obtained with 4, and mixed five-and six-coordinate geometries with a doubly bridged dimetal core were observed in 3. The magnetic properties of complexes 1-4 and 6 were studied at variable temperatures and revealed weak to very weak antiferromagnetic interactions in 1, 2, 4 and 6 (J = -0.55 to -9.4 cm(-1)) and ferromagnetic coupling in 3 (J = 15.4 cm(-1)). These results are consistent with DFT calculations performed at the B3LYP/def2-TZVP(-f) level of theory. Under physiological conditions, the interaction of the dinculear complexes 1-5 with supercoiled plasmid ds-DNA did not show any pronounced nuclease activity, but Ni(II) complexes 1 and 2 revealed a strong ability to unwind the supercoiled conformation of ds-DNA. The mechanistic studies performed on the interaction of the Ni(II) complexes with DNA demonstrated the important impact of the nickel(II) ion in the unwinding process. In combination with the DNA study, the phosphatase activity of complexes 1, 3, and 5 was examined by the phosphodiester hydrolysis of bis(2,4-dinitrophenol) phosphate (BDNPP) in the pH range of 5.5-10.5 at 25 degrees C. The Michaelis-Menten kinetics performed at pH 7 and 10.7 showed that catalytic efficiencies k(cat)/K-M (k(cat) = catalytic rate constant, K-M = substrate binding constant) decrease in the order: Ni(II), 1 > Zn(II), 5 > Cu(II), 3. A similar trend was also observed with the turnover numbers at pH = 7. The results are discussed in relation to the coordination geometry and nature of the metal center as well as the steric environment imposed by the compartmental phenoxido ligand.
机译：一系列双核金属（II）-乙酰复合物：[Ni-2（mu-（LO）-O-Cl）（mu（2）-OAc）（2）]（PF6）中心点3H（2）O（ 1），[Ni-2（mu-（LO）-O-Cl）（mu（2）-OAc）（2）]（ClO4）中心点CH3COCH3（2），[Cu-2（mu-（LO） -O-Cl）（mu（2）-OAc）（ClO4）]（ClO4）（3），[Cu-2（mu-（LO）-O-Cl）（OAc）（2）]（PF6）中心点H2O（4），[Zn-2（mu-（LO）-O-Cl）（mu（2）-OAc）（2）]（PF6）（5）和[Mn-2（L-Cl-O ）（mu（2）-OAc）（2）]（ClO4）中心点H2O（6），其中（LO-）-O-Cl = 2,6-双[双（双（2-吡啶基甲基）氨基甲基] -4-合成了氯酚盐。通过光谱技术和单晶X射线晶体学对复合物进行结构表征。在Ni（II），Zn（II）和Mn（II）配合物1、2、5和6中发现了具有双桥乙酰基配体的六坐标几何形状，而在Cu（II）配合物中获得了五坐标物种。在图4中，在3中观察到具有双桥双金属核的五坐标和六坐标混合几何。在可变温度下研究了配合物1-4和6的磁性，发现在1，2中存在弱至非常弱的反铁磁相互作用。 4和6（J = -0.55至-9.4 cm（-1）），铁磁耦合为3（J = 15.4 cm（-1））。这些结果与在B3LYP / def2-TZVP（-f）理论水平上进行的DFT计算一致。在生理条件下，小分子复合物1-5与超螺旋质粒ds-DNA的相互作用没有显示任何明显的核酸酶活性，但是Ni（II）复合物1和2显示出解开ds-DNA超螺旋构象的强大能力。 Ni（II）配合物与DNA相互作用的机理研究表明，Ni（II）离子在展开过程中具有重要影响。结合DNA研究，通过在25°C下于5.5-10.5的pH范围内通过双（2,4-二硝基苯酚）磷酸酯（BDNPP）的磷酸二酯水解来检查复合物1、3和5的磷酸酶活性。在pH 7和10.7下进行的Michaelis-Menten动力学表明，催化效率k（cat）/ KM（k（cat）=催化速率常数，KM =底物结合常数）按以下顺序降低：Ni（II），1> Zn （II），5> Cu（II），3。在pH = 7时，也观察到了类似的趋势。营业额与金属中心的配位几何形状和性质以及空间环境有关由隔间苯氧配体强加。

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