Supramolecular engineering of a 2D Kagomé lattice: synthesis, structures, and magnetic properties

Two 2D Mn (II) complexes, [Mn3(TzDC)2(phen)3] x 2 H2O (1; H3TzDC = 1,2,3-triazole-4,5-dicarboxylic acid, phen = 1,10-phenanthroline) and [Mn3(TzDC)2(bipy)3] x 4 H2O (2; bipy = 2,2'-bipyridine), were synthesized by hydrothermal reactions and characterized magnetically, and complex 1 was the first example of the chiral complex with a Kagomé lattice connectivity obtained through spontaneous resolution.     

A STUDY OF SOME POLYPYRIDYLRUTHENIUM(II) COMPLEXES AS DNA BINDERS AND PHOTOCLEAVAGE REAGENTS

The nature of the binding of several ruthenium polypyridyl complexes containing 2,2'-bipyridine (bipy), 4,4'-dimethyl-2,2'-bipyridine (DMB), 1,10-phenanthroline (phen), 4,7-diphenyl-1,10-phenanthroline (DPP), 2,2',2"-terpyridine (terpy), 2,2'-biquinoline (biq), 1,4,5,8-tetraazaphenanthrene (TAP) and 1,4,5,8,9,12-hexaazatriphenylene (HAT), with calf thymus DNA, poly[d(A-T)] and poly[d(G-C)] were studied by absorption and emission spectroscopy, DNA melting techniques, and emission lifetime measurements. In low ionic strength phosphate buffer, spectroscopic changes and DNA stabilization depended on the polypyridyl ligands present, and indicated binding that varied from substantially electrostatic to intercalative. Ru(bipy)2(HAT)2+ and Ru(phen)3(2+), which bind by partial intercalation, also show a strong preference for poly[d(A-T)]. The emission quantum yields for most complexes were increased in the presence of DNA. An exception was Ru(TAP)3(2+) which has a markedly reduced emission quantum yield and lifetime in the presence of poly[d(G-C)] or CT-DNA, due to photoredox interaction with quanines. Emission decays of the complexes generally showed multiexponential behaviour. The ability of the ruthenium complexes to sensitise DNA cleavage was determined using pBR322 plasmid DNA. Ru(TAP)3(2+) is the most efficient sensitiser while uncharged complexes and complexes with very short-lived excited states do not cleave DNA.     

Thermodynamic studies of the binding of bidentate nitrogen donors with methyltrioxorhenium (MTO) in CHCl3 solution

Methyltrioxorhenium (MTO) adduct formation with bidentate nitrogen donors 2,2'-bipyridine (bpy), 4,4'-dimethyl-2,2'-bipyridine (Me(2)bpy), 4,4'-di-tert-butyl-2,2'-bipyridine (tBu2bpy), 1,10-phenanthroline (phen), 5-methyl-1,10-phenanthroline (5-Mephen), 5-chloro-1,10-phenanthroline (5-Clphen), 4,7-dimethyl-1,10-phenanthroline (Me2phen) has been studied at different temperatures in CHCl3 solution. Spectrophotometeric measurements have been carried out to obtain the thermodynamic parameters. All complexes are enthalpy stabilized whereas the entropy changes counteract the adduct formation. The results are discussed in terms of different basicities of the bidentate N-donors.     

Syntheses and Crystal Structures of One-dimensional Ni（Ⅱ） Complexes with 5-Tert-butyl Isophthalic Acid

Two new Ni（ Ⅱ） coordination polymers, {[Ni（tbip）（bipy）（H2O）]-0.5H2O}n 1 and [Ni（tbip）（phen）（H2O）]n 2 （Hatbip = 5-tert-butyl isophthalic acid, bipy = 2,2＇-bipyridine, phen = 1,10-phenanthroline）, have been synthesized under hydrothermal conditions and characterized by elemental analysis, X-ray diffraction, and IR spectroscopy. In the two polymers, H2tbip acts as a tridentate ligand. Compound 1 has a tbip bridged 1-D linear chain which is extended by hydrogen bonds into a 1-D double chain, while compound 2 exhibits a 1-D zigzag chain.     

Pyridine ring opening at room temperature at a rhenium tricarbonyl bipyridine complex

Pyridine ring opening occurs in the reaction of [Re(CO)3(MeIm)(bipy)]OTf with KN(SiMe3)2 followed by double methylation with methyl trifluoromethanesulfonate. Analogues of the neutral product of the initial deprotonation and of the product of the first methylation were isolated by using mesitylimidazole (MesIm) in place of methylimidazole (MeIm) and/or 1,10-phenanthroline (phen) instead of 2,2'-bipyridine (bipy).     

Synergic solvent extraction studies of gadolinium using a combination of the di(2-ethylhexyl)phosphoric acid and three adductants into kerosine/chloroform

The equilibrium extraction behaviour of Gd(III) using a chloroform/kerosine solution containing di(2-ethylhexyl)phosphoric acid (HDEHP), either alone or combined with one of three adductants, 1,10-phenanthroline monohydrate (phen), alpha,alpha'-dipyridyl(2,2'-bipyridine) (bipy) or trioctylphosphine oxide (TOPO) is described. The enhancement of the extraction by addition of such neutral adductants is explained in terms of adduct formation of the metal chelate in the organic phase. Among the three synergistic mixtures, 1,10-phenanthroline is the most promising for the extraction of the last member of light lanthanoids, gadolinium. Gadolinium ions are found to be extracted in the absence of phen, bipy or TOPO; the species was M(HA(2))(3) but M(HA(2))(3))(phen)(2) was found when phen was added and M(HA(2))(3)(bipy), M(HA(2))(3)(bipy)(2) was found when bipy was added and M(HA(2))(3)(TOPO) was found when TOPO was added. The compositions of the extracted species are obtained from the slope analysis method. pH (1 2 ) values were also obtained. The stoichiometry, extraction constants and stability constants of these systems were determined. Synergistic extraction can be carried out at lower pH.     

Characterization and biological activities of two copper(II) complexes with diethylenetriamine and 2,2'-bipyridine or 1,10-phenanthroline as ligands

Two new mixed ligand copper(II) complexes with diethylenetriamine, 2,2'-bipyridine and 1,10-phenanthroline have been synthesized. The crystal and molecular structures of [Cu(dien)(phen)](ClO(4))(2) and [Cu(dien)(bipy)](BF(4))(2) (dien=diethylenetriamine, phen=1,10-phenanthroline, bipy=2,2'-bipyridine) were determined by X-ray crystallography from single crystal data. These two complexes have similar structures. The EPR spectral data also suggest that these complexes have distorted square pyramidal geometry about copper(II). Anti-microbial and superoxide dismutase activities of these complexes have also been measured. They show the higher SOD activity than the corresponding simple Cu(II)-dien/Cu(II)-PMDT (PMDT=N,N,N',N',N'-pentamethyldiethylenetriamine) complexes because of a strong axial bond of one of the nitrogen atoms of the alpha-diimine. Both the complexes have been found to cleave plasmid DNA in the presence of co-reductants such as ascorbic acid and glutathione.     

Phenomenological model of spin crossover in molecular crystals as derived from atom-atom potentials

The method of atom-atom potentials, previously applied to the analysis of pure molecular crystals formed by either low-spin (LS) or high-spin (HS) forms (spin isomers) of Fe(II) coordination compounds (Sinitskiy et al., Phys. Chem. Chem. Phys., 2009, 11, 10983), is used to estimate the lattice enthalpies of mixed crystals containing different fractions of the spin isomers. The crystals under study were formed by LS and HS isomers of Fe(phen)(2)(NCS)(2) (phen = 1,10-phenanthroline), Fe(btz)(2)(NCS)(2) (btz = 5,5',6,6'-tetrahydro-4H,4'H-2,2'-bi-1,3-thiazine), and Fe(bpz)(2)(bipy) (bpz = dihydrobis(1-pyrazolil)borate, and bipy = 2,2'-bipyridine). For the first time the phenomenological parameters Γ pertinent to the Slichter-Drickamer model (SDM) of several materials were independently derived from the microscopic model of the crystals with use of atom-atom potentials of intermolecular interaction. The accuracy of the SDM was checked against the numerical data on the enthalpies of mixed crystals. Fair semiquantitative agreement with the experimental dependence of the HS fraction on temperature was achieved with use of these values. Prediction of trends in Γ values as a function of chemical composition and geometry of the crystals is possible with the proposed approach, which opens a way to rational design of spin crossover materials with desired properties.     

Synthesis, structures, and magnetic properties of transition metal compounds with 2,2'-dinitrobiphenyl-4,4'-dicarboxylate and N,N'-chelating ligands

Solvothermal reactions of Co(II), Ni(II), Zn(II) salts with 2,2'-dinitrobiphenyl-4,4'-dicarboxylate (dnpdc) and 2,2'-bipyridyl-like chelating ligands yielded five compounds formulated as [Co(dnpdc)(bipy)](n)·nH(2)O (1), [M(dnpdc)(phen)](n) (2, M = Co; 3, M = Ni; 4, M = Zn) and [Co(dnpdc)(biql)](n)·2nH(2)O (5) (bipy = 2,2'-bipyridine, phen = 1,10-phenanthroline and biql = 2,2'-biquinoline). With bipy or phen as coligands, compounds 1-4 exhibit isomorphous 3D M(dnpdc) metal-organic frameworks in which double carboxylate bridged chains are interlinked by the backbones of the dicarboxylate ligands. The bipy or phen ligands are involved in interchain hydrogen bonding or π-π interactions to form 1D zipper-like arrays in the rhombic channels of the frameworks, playing a templating role and determining the channel dimensions. The biql coligand is too bulky for the 1D double carboxylate bridged chain and the rhombic channel. Instead, in compound 5, the dnpdc ligands link metal ions into 1D zigzag metal-organic chains and the biql ligands are arranged into 2D (6,3) arrays through extensive π-π stacking interactions. In compounds 1-3, the double carboxylate bridges in the nonplanar syn-skew conformation mediate ferromagnetic interactions along the chains, while the chelating ligands provide supramolecular pathways for interchain antiferromagnetic interactions. The π-π interactions in 5 also evoke weak antiferromagnetic interactions.     

Synthesis, characterization and biological activity of ternary copper(II) complexes containing polypyridyl ligands

Ternary copper(II) complexes involving polypyridyl ligands in the coordination sphere of composition [Cu(tpy)(phen)](ClO4)2 (1), [Cu(tpy)(bipy)](ClO4)2 (2), [Cu(tptz)(phen)](ClO4)2 (3) and [Cu(tptz)(bipy)](BF4)2 (4) where tpy = 2,2':6',2'-terpyridine, tptz = 2,4,6-tri(2-pyridyl)-1,3,5-triazine, phen = 1,10-phenanthroline and bipy = 2,2'-bipyridine have been synthesized and characterized by elemental analysis, magnetic susceptibility, X-band e.p.r. spectroscopy and electronic spectroscopy. Single crystal X-ray of (1) has revealed the presence of a distorted square pyramidal geometry in the complex. Magnetic susceptibility measurements at room temperature were in the range of 1.77-1.81 BM. SOD and antimicrobial activities of these complexes were also measured. Crystal data of (1): P-1, a = 9.3010(7) A, b = 9.7900(6) A, c = 16.4620(6) A, Vc = 1342.73(14) A3, Z = 4. The bond distance of CuN in square base is 2+/-0.04 A.     

Syntheses,Crystal Structures and Properties of Co（Ⅱ） and Cu（Ⅱ） Complexes with 5-Nitro-1,2,3-benzenetricarboxylic Acid

Two new coordination polymers,{[Co(O2N-Hbtb)(phen)(H2O)3]·2H2O}n 1 and {[Cu3(O2N-btb)2(bipy)2(H2O)4]·4H2O}n 2(O2N-H3btb=5-nitro-1,2,3-benzenetricarboxylic acid,phen=1,10-phenanthroline,bipy=2,2'-bipyridine),were prepared through hydrothermal reactions of Co(Ⅱ) or Cu(Ⅱ) salt with O2N-H3btb in the presence of different auxiliary N-donor ligands.Their crystal structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectroscopy.In the two complexes,O2N-H3btb ligand acts as monodentate and bis-monodentate modes,respectively.Complex 1 displays a two-dimensional layered structure through the inter-and intramolecular hydrogen bonding interactions while complex 2 has an O2N-btb bridged one-dimensional chain which is extended into a three-dimensional network by hydrogen bonding interactions.The magnetic properties of complex 2 are investigated over the temperature range of 2～300 K and ferromagnetic interactions are observed.     

Synthesis, crystal structures and magnetic properties of single and double cyanide-bridged bimetallic Fe2(III)Cu(II) zigzag chains

The bimetallic complexes [[Fe(III)(phen)(CN)4]2Cu(II)(H2O)2].4H2O (1), [[Fe(III)(phen)(CN)4]2Cu(II)].H2O (2) and [[Fe(III)(bipy)(CN)4]2Cu(II)].2H2O (3) and [[Fe(III)(bipy)(CN)4]2Cu(II)(H2O)2].4H2O (4) (phen = 1,10-phenanthroline and bipy = 2,2'-bipyridine) have been prepared and the structures of 1-3 determined by X-ray diffraction. The structure of 1 is made up of neutral cyanide-bridged Fe(III)-Cu(II) zigzag chains of formula [[Fe(III)(phen)(CN)4]2Cu(II)(H2O)2] and uncoordinated water molecules with the [Fe(phen)(CN)4]- entity acting as a bis-monodentate bridging ligand toward two trans-diaquacopper(II) units through two of its four cyanide groups in cis positions. The structure of 2 can be viewed as the condensation of two chains of 1 connected through single cyanide-bridged Fe(III)-Cu(II) pairs after removal of the two axially coordinated water molecules of the copper atom. The structure of 3 is like that of 2, the main differences being the occurrence of bipy (phen in 2) and two (one in 2) crystallization water molecules. The crystals of 4 diffract poorly but the analysis of the limited set of diffraction data shows a chain structure like that of 1 the most important difference being the fact that elongation axis at the copper atom is defined by the two trans coordinated water molecules. 1 behaves as a ferromagnetic Fe(III)2Cu(II) trinuclear system. A metamagnetic-like behavior is observed for 2 and 3, the value of the critical field (Hc) being ca. 1100 (2) and 900 Oe (3). For H > Hc the ferromagnetic Fe(III)2Cu(II) chains exhibit frequency dependence of the out-of-phase ac susceptibility signal at T < 4.0 K. The magnetic behavior of 4 corresponds to that of a ferromagnetically coupled chain of low spin iron(III) and copper(II) ions with frequency dependence of the out-of-phase susceptibility at T < 3.0 K. Theoretical calculations using methods based on density functional theory (DFT) have been employed to analyze and substantiate the exchange pathways in this family of complexes.     

Intramolecular "Aryl-metal chelate ring" pi,pi-interactions as structural evidence for metalloaromaticity in (aromatic alpha,alpha'-diimine)-copper(II) chelates: molecular and crystal structure of aqua(1,10-phenanthroline)(2-benzylmalonato)copper(II) three-hydrate

By reaction of Cu(2)CO(3)(OH)(2), 2-benzylmalonic acid (H(2)Bzmal), and 1,10-phenanthroline (phen), [Cu(Bzmal)(phen)(H(2)O)] x 3H(2)O (compound 1) has been obtained and characterized by thermal, spectral, magnetic, and X-ray diffraction methods. The molecular structure of 1 is remarkably similar to that of [Cu(Bzmal)(bipy)(H(2)O)] x 2H(2)O (compound 2, bipy = 2,2'-bipyridine). In both complexes, the aryl(Bzmal) ring produces an unexpected pi,pi-stacking interaction with the Cu(II)-(aromatic alpha,alpha'-diimine) chelate ring, at an average distance d(pi)(-)(pi) of 3.40 A, involving roughly parallel and smoothly slipped rings. This insight is discussed as new structural evidence for metalloaromaticity of Cu(II)-(aromatic alpha,alpha'-diimine) chelate rings. Interestingly, 1 recognizes itself by a weak intermolecular pi,pi-stacking interaction between aryl(Bzmal) ligands to give pairs of complex molecules. In contrast, there is an intermolecular pyridyl-pyridyl pi,pi-stacking interaction also forming pairs of complex molecules in 2.     

N,N'-乙二水杨酰胺合铜(II)酸根和N,N'-1,2-丙二水杨酰胺全铜(II)酸根的双核Cu(II)-Fe(III)配合物的合成和磁性

本文合成了四个新型双核配合物、[Cu(samen)Fe(L)Cl]和[Cu(sampn)Fe(L)Cl]。经元素分析、IR, 电导、磁性测量等手段推定配合物具有酚氧桥结构, Cu(II)及Fe(III)的配位环境分别为平面四方及四角锥的构型, Fe(III)离子的自旋态S=3/2。测定了配合物[Cu(samen)Fe(L)Cl]的变温磁化率(4-300K), 参数J和θ值表明两个双核配合物中金属离子之间有中等程度的反铁磁性超交换作用和双核单元之间有弱的分子间相互作用。     

Thermal and light induced polymorphism in iron(II) spin crossover compounds

The spin crossover complexes [Fe[H(2)B(pz)(2)](2)L]([H(2)B(pz)(2)](-)= dihydrobis(pyrazolyl)borate, L = 2,2[prime or minute]-bipyridine (1), bipy and 1,10-phenanthroline, phen (2)) undergo both thermal and light induced spin crossover, but the structure of the low spin and light induced high spin states for are different from that of the thermally induced high spin state and from those of.     

Iron(III) mixed-ligand complexes: Synthesis,characterization and crystal structure determination of iron(III) hetero-ligand complexes containing 1,10-phenanthroline, 2,2′-bipyridine,chloride and dimethyl sulfoxide, [Fe(phen)Cl3(DMSO)] and [Fe(bipy)Cl3(DMSO)]

Treatment of [Fe(bipy)Cl₄][bipy · H] (1) and [Fe(phen)Cl₄][phen · H] (3) (where bipy is 2,2′-bipyridine and phen is 1,10-phenanthroline) with dimethyl sulfoxide in methanolic solution produced [Fe(bipy)Cl₃(DMSO)] (2) and [Fe(phen)Cl₃(DMSO)] (4) (where DMSO is dimethyl sulfoxide), respectively. The resulting complexes were characterized by elemental analysis, IR, UV–Vis and ¹H NMR spectroscopies and by the X-ray diffraction method. These complexes are high spin with a spin multiplicity of 6.     

Synthesis of heteroleptic bis(diimine)carbonylchlororuthenium(II) complexes from photodecarbonylated precursors

The reactions of bidentate diimine ligands (L2) with binuclear [Ru(L1)(CO)Cl2]2 complexes [L1 not equal to L2 = 2,2'-bipyridine (bpy), 4,4'-dimethyl-2,2'-bipyridine (4,4'-Me2bpy), 5,5'-dimethyl-2,2'-bipyridine (5,5'-Me2bpy), 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (4,7-Me2phen), 5,6-dimethyl-1,10-phenanthroline (5,6-Me2phen), di(2-pyridyl)ketone (dpk), di(2-pyridyl)amine (dpa)] result in cleavage of the dichloride bridge and the formation of cationic [Ru(L1)(L2)(CO)Cl]+ complexes. In addition to spectroscopic characterization, the structures of the [Ru(bpy)(phen)(CO)Cl]+, [Ru(4,4'-Me2bpy)(5,6-Me2phen)(CO)Cl]+ (as two polymorphs), [Ru(4,4'-Me2bpy)(4,7-Me2phen)(CO)Cl]+, [Ru(bpy)(dpa)(CO)Cl]+, [Ru(5,5'-Me2bpy)(dpa)(CO)Cl]+, [Ru(bpy)(dpk)(CO)Cl]+, and [Ru(4,4'-Me2bpy)(dpk)(CO)Cl]+ cations were confirmed by single crystal X-ray diffraction studies. In each case, the structurally characterized complex had the carbonyl ligand trans to a nitrogen from the incoming diimine ligand, these complexes corresponding to the main isomers isolated from the reaction mixtures. The synthesis of [Ru(4,4'-Me2bpy)(5,6-Me2bpy)(CO)(NO3)]+ from [Ru(4,4'-Me2bpy)(5,6-Me2bpy)(CO)Cl]+ and AgNO3 demonstrates that exchange of the chloro ligand can be achieved.     

系列Cu(Ⅱ/Ⅰ)配合物的制备及其表面光电压

采用水热法合成了{[Cu(phen)(H2O)(o-tpha)]·H2O}n(1), [Cu2Cl4(phen)2](2), [Cu4Cl4·(bipy)2](3)和[Cu2Cl2(phen)]n(4)(bipy=2,2'-bipyridyl, phen=1,10-phenanthroline, o-H2tpha=o-phthalic acid)4个铜配合物. X射线单晶衍射结果表明, 配合物1和4是具有一维无限结构的聚合物, 配合物2是双核Cu(Ⅱ) 配合物并由氢键连成超分子, 配合物3是四核Cu(Ⅰ) 簇合物. 常温下测定了4个配合物的表面光电压光谱(SPS)、场诱导表面光电压光谱(FISPS)、IR和UV-Vis-NIR光谱. SPS的测试结果显示, 4个化合物均在300~800 nm范围内存在光伏响应带, 但是它们呈现了不同的特性. 配合物1~3的表面光电压光谱呈现出正的表面光伏响应(SPV), 配合物4的SPS呈现出负的表面光伏响应. 4个配合物的表面光伏响应带的位置、数量以及强度均有明显不同.     

Three novel zinc(II) sulfonate-phosphonates with tetranuclear or hexanuclear cluster units

Hydrothermal reactions of zinc(II) carbonate with m-sulfophenylphosphonic acid (m-HO3S-Ph-PO3H2) and 1,10-phenanthroline (phen) or 4,4'-bipyridine (bipy) lead to three novel zinc(II) sulfonate-phosphonates, namely, [Zn(phen)3]2[Zn4(m-O3S-Ph-PO3)4(phen)4].20H2O (1), [Zn6(m-O3S-Ph-PO3)4(phen)8].11H2O (2), and [Zn6(m-O3S-Ph-PO3)4(bipy)6(H2O)4].18H2O (3). Compound 1 contains a tetranuclear zinc(II) cluster anion in which four Zn(II) ions are bridged by two tetradentate and two bidentate phosphonate groups, and the four negative charges of the cluster are compensated by two [Zn(phen)3]2+ cations. Compound 2 features a hexanuclear zinc(II) cluster in which the same tetranuclear cluster of 1 is bridged with two additional Zn(II) ions. The structure of 3 features a porous 3D network based on hexanuclear zinc(II) units of [Zn6(m-O3S-Ph-PO3)4] interconnected by 4,4'-bipy ligands. The hexanuclear cluster in 3 is different from that in 2 in that all four phosphonate groups in 3 are tridentate bridging. Compounds 1, 2, and 3 exhibit broad blue fluorescent emission bands at 378, 409, and 381 nm, respectively.     

Large improvement in the catalytic activity due to small changes in the diimine ligands: new mechanistic insight into the dirhodium(II,II) complex-based photocatalytic H2 production

Two dirhodium(II) complexes, [Rh(II)(2)(μ-O(2)CCH(3))(2)(bpy)(2)](O(2)CCH(3))(2) (Rh(2)bpy(2); bpy = 2,2'-bipyridine) and [Rh(II)(2)(μ-O(2)CCH(3))(2)(phen)(2)](O(2)CCH(3))(2) (Rh(2)phen(2); phen = 1,10-phenanthroline) were synthesized, and their photocatalytic H(2) production activities were studied in multicomponent systems, containing [Ir(III)(ppy)(2)(dtbbpy)](+) (ppy = 2-phenylpyridine, dtbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine) as the photosensitizer (PS) and triethylamine as the sacrificial reductant (SR). There is a more than 6-fold increase in the photocatalytic activity from Rh(2)bpy(2) to Rh(2)phen(2) just using phen in place of bpy. A turnover number as high as 2622 was obtained after 50 h of irradiation of a system containing 16.7 μM Rh(2)phen(2), 50 μM PS, and 0.6 M SR. The electrochemical, luminescence quenching, and transient absorption experiments demonstrate that Rh(I)Rh(I) is the true catalyst for the proton reduction. The real-time absorption spectra confirm that a new Rh-based species formed upon irradiation of the Rh(2)phen(2)-based multicomponent system, which exhibits an absorption centered at ～575 nm. This 575-nm intermediate may account for the much higher H(2) evolution efficiency of Rh(2)phen(2). Our work highlights the importance of N-based chelate ligands and opens a new avenue for pursuing more efficient Rh(II)(2)-based complexes in photocatalytic H(2) production application.