Synthesis,characterization and interaction of mixed polypyridyl ruthenium(II) complexes with calf thymus DNA

New mixed polypyridyl {HPIP = 2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline, phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, dmb = 4,4-dimethyl-2,2-bipyridine} ruthenium(II) complexes [Ru(phen)₂(HPIP)]²⁺, [Ru(dmp)₂(HPIP)]²⁺ and [Ru(dmb)₂(HPIP)]²⁺ were synthesized and characterized by elemental analyses ¹H-n.m.r., u.v.–vis. spectroscopy and cyclic voltammetry. Their DNA-binding properties were demonstrated by absorption, luminescence titrations, steady-state emission quenching and viscosity measurements. The results suggested that all the examined complexes bind with CT-DNA intercalatively. Methyl groups substituted at the 4,4-positions of bpy has no obvious effect on its DNA binding, whereas substituents at the 2- and 9-positions of phen have an impressive effect on its DNA-binding, as revealed by the decreased binding affinity.     

DNA intercalating studies of [Ru(bpy)<Subscript>2</Subscript>HPIP]<Superscript>2+</Superscript> with intramolecular hydrogen bond ligand based on introduction of copper ion

The effects of copper ion on the interaction of [Ru(bpy)₂HPIP]²⁺(bpy = 2,2′-bipyridine, HPIP = 2-(2-hydroxyphenyl) imidazo [4,5-f] [1, 10] phenanthroline) with DNA have been investigated by electronic absorption spectroscopy and fluorescence spectroscopy. HPIP ligand of the complex with an intramolecular hydrogen bond can bind Cu²⁺ in the absence of DNA, as revealed by the absorbance and fluorescence decrease for [Ru(bpy)₂HPIP]²⁺. The resultant heterometallic complex binds to DNA via intercalation of HPIP into the DNA base pairs and its DNA-binding ability is stronger than [Ru(bpy)₂HPIP]²⁺ itself. The DNA bound [Ru(bpy)₂HPIP]²⁺ cannot bind Cu²⁺ at low Cu²⁺ concentration and the intramolecular hydrogen bond in HPIP is located inside the DNA helix. While the Cu²⁺ concentration is relative high, Cu²⁺ can quench the fluorescence of DNA bound [Ru(bpy)₂HPIP]²⁺. The quenching reason is proposed.     

单核铁(Ⅲ)双卟啉配合物在溶液中的构象平衡及其对环己烷羟化反应的催化活性的影响

合成及表征了一系列以柔韧碳氢链相连不同长度的ｐ／ｐ型单核铁（Ⅲ）双卟啉配合物，以可见光谱首次观察到该系列配合物在氯仿溶液中开放式及闭合式构象的平衡，发现６８０ｎｍ处吸收峰强度与这种构象平衡有关，烷氧链越长，该吸收峰强度越大．利用该类配合物模拟了细胞色素Ｐ４５０单加氧酶对环己烷的羟化作用，催化结果表明，在以分子氧为氧源及还原剂存在的温和条件下，该类配合物的催化活性显著高于单核铁卟啉（ＦｅＴＰＰＣｌ），随着柔韧碳氢链长度的增加，双卟啉的催化活性依次增加．高的催化活性与双卟啉配合物在溶液中的构象平衡，即闭合式构象引起的立体位阻及电子转移有关．     

Photochemical reaction of Rh2(CO)4(μ-TPP)(TPP=tetraphenyl-porphyrinato) with pyridine (Py) in benzene. Generation of a mononuclear rhodium(II) porphyrin radical complex Rh(TPP)(Py)

Photolytic decarbonylation of Rh₂(CO)₄(TPP) (TPP=tetraphenylporphyrinato) with pyridine (Py) in benzene gives an unusual monomeric Rh^II radical complex Rh(TPP)(Py), which has been characterised by thermal and spectroscopic measurements and by vapour pressure osmosis.     

配体形状对多吡啶铜(Ⅱ)配合物与DNA作用的影响

合成了一系列含有平面配体的Cu(Ⅱ)多吡啶配合物[Cu(IP)₂]²⁺、[Cu(PIP)₂]²⁺、[Cu(DPPZ)₂]²⁺和[Cu(HPIP)₂]²⁺，用吸收光谱、CD光谱和粘度等方法研究了这些配合物与小牛胸腺DNA的作用。结果表明配体上的取代基及配体的平面性对这些四面体配合物与DNA的结合强弱产生一定的影响。[Cu(DPPZ)₂]²⁺与DNA的结合较强，而[Cu(HPIP)₂]²⁺与DNA的结合较弱。CD光谱显示配合物[Cu(DPPZ)₂]²⁺、[Cu(PIP)₂]²⁺和[Cu(HPIP)₂]²⁺的加入会导致DNA的CD光谱减弱。而[Cu(IP)₂]²⁺的加入则会使DNA的CD光谱增强。同时，[Cu(IP)₂]²⁺与DNA结合后，还会引起一定程度的DNA构型转换，即DNA从B型转换成Z型。     

Synthesis,structure and DNA-binding studies on the 2-(3-chlorophenyl)imidazo[4,5-f]1,10-phenanthroline-bis(2,2′-bipy ridine)-ruthenium(II) complex

A new polypyridyl ligand, MCP {MCP = 2-(3-chlorophenyl)imidazo[4,5-f]1,10-phenanthroline} and its ruthenium(II) complex, [Ru(bpy)2(MCP)](ClO4)2· 0.5MeCN (bpy = 2,2-bipyridine), have been synthesized and characterized. The structure of the complex was determined by single crystal X-ray diffraction techniques. The MCP ligand is essentially planar and the stacking interactions between the ligands were observed in the crystal. [Ru(bpy)2(MCP)]2+ can strongly bind to Calf thymus DNA through intercalation of MCP ligand. The Cl substitute group has no significant effect on the spectral properties and DNA-binding behaviour of the complex.     

单核锌双卟啉配合物构象平衡的理论研究及光谱分析

合成了一系列以不同长度柔韧链相连的p/p型单核锌双卟啉配合物。选用Tripos力场,利用分子动力学模拟退火和分子力学构象搜索相结合的方法对该系列双卟啉进行了能量优化和构象分析。理论计算结果表明:该类双卟啉稳定存在的最低能量构象为叠合式,最高能量构象为伸展式,并存在一系列的中间能量构象;双卟啉分子内π-π作用和能量转移与双卟啉存在的两种主要构象密切相关;分析了分子内π-π作用的本质。运用不同光谱测试手段验证了理论计算结果: 利用可见和相应二阶导数吸收光谱研究了双卟啉主要存在的叠合式和伸展式构象,通过红外光谱观察了对双卟啉构象和卟啉环间π-π作用较为敏感的吸收谱带;利用荧光光谱计算了双卟啉的分子内能量转移效率。     

配体的空间构型及疏水性对钌（Ⅱ）多吡啶配合物与DNA作用的影响

合成了4－氰基苯基咪唑并[5,6-f]邻菲咯啉（CYIP）和2－羧基苯基咪唑并[5, 6-f]邻菲咯啉（COIP）两种新配体及它们的钌混配配合物[Ru(bpy)2CYIP](ClO4)2 ·H2O（Rul）（bpy=2,2′-联吡啶），[Ru(phen)2CYIP](ClO4)2·H2O(Ru2) (phen=1,10-邻菲咯啉），[Ru(bpy)2COIP](ClO4)2·3H2O(Ru3)和[Ru(phen)2COIP] (ClO4)2·H2O(Ru4)，并用红外光谱、紫外光谱、核磁和质谱对它们进行了表征。 通过循环伏安法研究了这些配合物的电化学性质。采用电子吸收光谱、稳态荧光、 圆二色谱和粘度测定研究了配合物与小牛胸腺DNA的相互作用。结果表明配合物 Rul和Ru2通过CYIP配体以插入的方式与DNA结合，而配合物Ru3和Ru4则通过COIP配 体以部分插入的方式与DNA结合。     

多吡啶钴(Ⅲ)配合物与Zn2+形成的新型“关-开”荧光探针

近十几年来,对小分子过渡金属配合物与大分子DNA键合与识别机理的研究一直是国际上生物无机化学领域十分活跃的研究课题[1￣3],已发展了一系列具有特定功能的配合物,如DNA结构探针和DNA荧光探针等。与其他类型的金属配合物相比,八面体过渡金属多吡啶配合物具有丰富的光化学和光物理信息,当这些配合物与DNA相互作用时,由于结构匹配或微环境的差异,配合物的光谱特征会出现不同程度的改变,从而达到对DNA的检测。传统的DNA荧光探针有[Ru(bpy)2dppz]2 和[Ru(phen)2dppz]2 (bpy=2,2′-联吡啶,phen=1,10-菲咯啉,dppz=二吡啶[3,2-a∶2′,3′…     

DNA Interactions of a Dinuclear Ruthenium(II) Complex Bridged by 1,3-bis(1,10-phenanthroline[5,6-d]imidazol-2-yl)benzene

A novel dinuclear ruthenium(II) complex [(phen)₂Ru(mbpibH₂)Ru(phen)₂]⁴⁺ [phen = 1,10-phenanthroline; mbpibH₂ = 1,3-bis(1,10-phenanthroline[5,6-d]imidazol-2-yl)-benzene] has been synthesized and characterized. The DNA-binding behavior of this complex has been studied by spectroscopic and viscosity measurements. Results suggest that the dinuclear ruthenium(II) complex intercalates into DNA base pairs via its bridging moiety. It has also been found that the dinuclear ruthenium(II) complex displays the enantiopreferential DNA-binding after equilibrium dialysis.