Hydrogenation and hydrogenolysis of furfural and furfuryl alcohol catalyzed by ruthenium(II) bis(diimine) complexes

The catalytic activity of ruthenium(II) bis(diimine) complexes cis‐[Ru(6,6′‐Cl₂bpy)₂(OH₂)₂](Z)₂ ( 1 , Z = CF₃SO₃; 2 , Z = (3,5‐(CF₃)₂C₆H₃)₄B, i.e. BArF) and cis‐[Ru(4,4′‐Cl₂bpy)₂(OH₂)₂](Z)₂ ( 3 , Z = CF₃SO₃; 4 , Z = BArF) for the hydrogenation and/or the hydrogenolysis of furfural (FFR) and furfuryl alcohol (FFA) was investigated. The molecular structures of cis‐[Ru(4,4′‐Cl₂bpy)₂(CH₃CN)₂](CF₃SO₃)₂ ( 3 ′) and dimeric cis‐[(Ru(4,4′‐Cl₂bpy)₂Cl)₂](BArF)₂ ( 5 ) were characterized by X‐ray crystallography. The structures are consistent with the anticipated reduction in steric hindrance about the ruthenium centers in comparison with corresponding complexes containing 6,6′‐Cl₂bpy ligands. While compounds 1 , 2 , 3 , 4 are all active and highly selective catalysts for the hydrogenation of FFR to FFA under modest reaction conditions, 3 and 4 showed decreased activity. This is best explained in terms of reduced Lewis acidity of the Ru²⁺ centers and reduced steric hindrance about the metal centers of catalysts 3 and 4 . cis‐[Ru(6,6′‐Cl₂bpy)₂(OH₂)₂](BArF)₂ ( 2 ) also displayed high catalytic efficiency for the hydrogenation of FFA to tetrahydrofurfuryl alcohol. Presumably, this is because coordination of C═C bonds of FFA to the ruthenium center is poorly inhibited by non‐coordinating BArF counterions. Interestingly, cis‐[Ru(6,6′‐Cl₂bpy)₂(OH₂)₂](CF₃SO₃)₂ ( 1 ) showed some catalytic activity in ethanol for the hydrogenolysis of FFA to 2‐methylfuran, albeit with fairly modest selectivity. Nonetheless, these results indicate that ruthenium(II) bis(diimine) complexes need to be further explored as catalysts for the hydrogenolysis of C―O bonds of FFR, FFA, and related compounds. Copyright © 2012 John Wiley & Sons, Ltd.     

Three new mixed‐ligand copper(II) complexes containing glycyl‐l‐valine and N,N‐aromatic heterocyclic compounds: Synthesis,characterization, DNA interaction,cytotoxicity and antimicrobial activity

Three novel copper(II) complexes, [Cu(Gly‐l ‐Val)(HPBM)(H₂O)]·ClO₄·H₂O ( 1 ), [Cu(Gly‐l ‐Val)(TBZ)(H₂O)]·ClO₄ ( 2 ) and [Cu(Gly‐l ‐Val)(PBO)(H₂O)]·ClO₄ ( 3 ) (Gly‐l ‐Val = glycyl‐l ‐valine anion, HPBM = 5‐methyl‐2‐(2′‐pyridyl)benzimidazole, TBZ = 2‐(4′‐thiazolyl)benzimidazole, PBO = 2‐(2′‐pyridyl)benzoxazole), have been prepared and characterized with elemental analyses, conductivity measurements as well as various spectroscopic techniques. The interactions of these copper complexes with calf thymus DNA were explored using UV–visible, fluorescence, circular dichroism, thermal denaturation, viscosity and docking analyses methods. The experimental results showed that all three complexes could bind to DNA via an intercalative mode. Moreover, the cytotoxic effects were evaluated using the MTT method, and the antimicrobial activity of these complexes was tested against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The results showed that the activities are consistent with their DNA binding abilities, following the order of 1 > 2 > 3 .     

Reaktive E=C(p‐p)π‐Systeme. 54 [1] Reaktionen des Perfluor‐2‐arsapropens,F3CAs=CF2 (1), mit H‐aciden Verbindungen Me2EH (E = N,P, As) und MeE′H (E′ = O,S, Se)

Reactive E=C(p‐p)π‐Systems. 54 [1] Reactions of perfluoro‐2‐arsapropene, F₃CAs=CF₂ (1), with H‐acidic compounds Me₂EH (E = N, P, As) and MeE′H (E′ = O, S, Se) The reactions of the perfluoro‐2‐arsapropene ( 1 ) with H‐acidic compounds Me₂EH (E = N, P, As) and MeE′H (E′ = O, S, Se), respectively, proceed via addition to the As=C double bond yielding either secondary arsanes F₃C(H)AsCF₂X (X = NMe₂, PMe₂, OMe, SMe) or AsX derivatives (X = AsMe₂, SeMe). Me₂‐AsH is obviously a border case nucleophile because, besides the AsX derivative as main product, small amounts of the arsane are formed indicative for the reverse addition pathway. With the strong base Me₂NH, the addition is followed immediately by HF elimination producing the fairly stable arsaalkene F₃CAs=C(F)NMe₂ ( 4 ) which had already been obtained by reaction of HAs(CF₃)₂ with three equivalents of Me₂NH. The novel rather labile compounds were identified by spectroscopic (NMR, GC/MS) investigations. – Quantum chemical DFT calculations [B3LYP/6‐311+G(d,p)] were carried out to determine the relative energy of the isomeric products and the thermodynamics of the addition reactions.     

Crystallographic report: Crystal structures of organometallic aqua complexes [Cp*RhIII(bpy)(OH2)]2+ and [Cp*RhIII(6,6′‐Me2bpy)(OH2)]2+ used as key catalysts in regioselective reduction of NAD+ analogues

Crystal structures of organometallic aqua complexes [Cp*Rh^III(bpy)(OH₂)]²⁺ ( 1 , Cp* = η⁵‐C₅Me₅, bpy = 2,2′‐bipyridine) and [Cp*Rh^III(6,6′‐Me₂bpy)(OH₂)]²⁺ ( 2 , 6,6′‐Me₂bpy = 6,6′‐dimethyl‐2,2′‐bipyridine) used as key catalysts in regioselective reduction of NAD⁺ analogues were determined definitely by X‐ray analysis. The yellow crystals of 1 (PF₆)₂ and orange crystals of 2 (CF₃SO₃)₂ used in the X‐ray analysis were obtained from aqueous solutions of 1 (PF₆)₂ and 2 (CF₃SO₃)₂. The Rh–O_aqua length of 2.194(4) Å obtained for 1 (PF₆)₂ is significantly different from that of 2.157(3) Å obtained for the previously reported disorder model [Cp*Rh^III(bpy)(0.7H₂O/0.3CH₃OH)](CF₃SO₃)₂·0.7H₂O in which the coordinated water is replaced by a coordinated methanol. The five‐membered ring involving the Rh atom and the 6,6′‐Me₂bpy chelating unit in 2 (CF₃SO₃)₂ is not flat, whereas the five‐membered chelate ring in 1 (PF₆)₂ is nearly flat. Such a non‐planar structure in 2 (CF₃SO₃)₂ is ascribed to the steric repulsion between the 6,6′‐Me₂bpy ligand and the Cp* ligand. Copyright © 2005 John Wiley & Sons, Ltd.     

碳链长度对芳香异羟肟酸二烃基锡配合物与5’-AMP或DNA相互作用的影响

选择体外筛选活性强的Bu₂Sn(4-FC₆H₄C(O)NHO)₂和活性弱的有机锡化合物Me₂Sn(4-FC₆H₄C(O)NHO)₂为模型,利用高分辨¹H NMR和³¹P NMR 技术比较研究这两个有代表性的有机锡化合物与DNA的基本组成单元5’-AMP在不同时间、不同条件下的作用模式并用紫外法进一步研究其与DNA的相互作用。结果显示,具有不同碳链的有机锡化合物与5’-AMP相互作用明显不同,含较长碳链的Bu₂Sn(4-FC₆H₄C(O)NHO)₂与5’-AMP的作用明显强于Me₂Sn(4-FC₆H₄C(O)NHO)₂,Me₂Sn(4-FC₆H₄C(O)NHO)₂分子可能只与5’-AMP的磷酸骨架静电结合,与整个分子作用较弱,而含丁基的Bu₂Sn(4-FC₆H₄C(O)NHO)₂可能除了与磷酸骨架静电结合,也与疏水碱基具有超分子相互作用而更有利于与5’-AMP稳定结合。Bu₂Sn(4-FC₆H₄C(O)NHO)₂的长链有机配体在与DNA的作用模式上发挥了重要作用。     

Preparation and properties of perfluorochloromethyl-mercaptophosphoryldichlorides and -chlorophosphanes

In Arbuzov-type reactions CF_nCl_3?nSCl reacts with ROPCl₂ (R = CH₃, C₂H₅) to give CF_nCl_3?nSP(O)Cl₂ (n = 3,2,1,0). The corresponding reaction with CF₃SeX (X = Cl, Br) produces CF₃SeP(O)Cl₂ in good yields only in the presence of catalysts such as SbCl₅ or BCl₃. Reactions between P₄ and the sulfenylchlorides produce (CF_nCl_3?nS)_xPCl_3?n (n = 3,2,1 and x = 1,2). On heating CF_n′ Cl_3?n′ SP(O)Cl₂ (n′ = 2,1,0) decompose to P(O)Cl₃ and SCF_n′ Cl_2?n′. During this process fluorination of P(O)Cl₃ to P(O)F₃ by SCF₂ is observed. A Cl/Br exchange between CF_nCl_3?nSP(O)Cl₂ (n = 3,2) and PBr₃ was proved ¹⁹F? and ³¹P-NMR-spectroscopically.Chemical and physical properties of the newly synthesized compounds will be discussed.     

Darstellung und Eigenschaften von Trifluormethylmercaptothiophosphoryldichlorid

Preparation and Properties of Trifluoromethylmercaptothiophosphoryldichloride The reaction of CF₃SP(O)Cl₂ with SPCl₃ leads to a CF₃S-chlorine exchange and gives CF₃SP(S)Cl₂ in 50% yield. A controlled hydrolysis of CF₃SP(O)Cl₂ affords CF₃SP(O)(OH)₂, that cannot be isolated as such, but it condenses to CF₃SP(O)(OH)O? [P(SCF₃)(O)? O]_nP(O)(OH)SCF₃. On the other hand, CF₃SP(S)Cl₂ reacts with water to yield H₃PO₄, CF₃SH, S₈, and HCl. CF₃SP(X)Cl₂ reacts with alcohols to give CF₃SP(X)(OR)₂ [R = CH₃, C₂H₅, n-C₃H₇, CH(CH₃)₂, n-C₄H₉ and for X = O, R = C₆H₅, too]. The formation of semi-esters CF₃SP(X)Cl(OR′) could be proven for X = O, R′ = CH₃, C₆H₅ and for X = S, R′ = R. While CF₃SP(O)(OC₂H₅)₂ rapidly decomposes into SCF₂ and FP(O)(OC₂H₅)₂, the other compounds and primarily CF₃SP(O)(OCH₃)₂ and CF₃SP(S)(OR)₂ ar stable. The reaction between CF₃SCl and CH₃SPCl₂ results in CF₃SCH₂SPCl₂ and that between CF₃SP(O)Cl₂ and AlCl₃ gives [CF₃SP(O)Cl]⁺[AlCl₄]^?. Physical and spectroscopical data are given for the newly formed compounds.     

Dynamic Equilibria in Solvent‐Mediated Anion,Cation and Ligand Exchange in Transition‐Metal Coordination Polymers: Solid‐State Transfer or Recrystallisation?

The solution properties of a series of transition‐metal–ligand coordination polymers [ML(X)_n]_∞ [M=Ag^I, Zn^II, Hg^II and Cd^II; L=4,4′‐bipyridine (4,4′‐bipy), pyrazine (pyz), 3,4′‐bipyridine (3,4′‐bipy), 4‐(10‐(pyridin‐4‐yl)anthracen‐9‐yl)pyridine (anbp); X=NO₃^?, CH₃COO^?, CF₃SO₃^?, Cl^?, BF₄^?; n=1 or 2] in the presence of competing anions, metal cations and ligands have been investigated systematically. Providing that the solubility of the starting complex is sufficiently high, all the components of the coordination polymer, namely the anion, the cation and the ligand, can be exchanged on contact with a solution phase of a competing component. The solubility of coordination polymers is a key factor in the analysis of their reactivity and this solubility depends strongly on the physical properties of the solvent and on its ability to bind metal cations constituting the backbone of the coordination polymer. The degree of reversibility of these solvent‐induced anion‐exchange transformations is determined by the ratio of the solubility product constants for the starting and resultant complexes, which in turn depend upon the choice of solvent and the temperature. The extent of anion exchange is controlled effectively by the ratio of the concentrations of incoming ions to outgoing ions in the liquid phase and the solvation of various constituent components comprising the coordination polymer. These observations can be rationalised in terms of a dynamic equilibrium of ion exchange reactions coupled with Ostwald ripening of crystalline products. The single‐crystal X‐ray structures of [Ag(pyz)ClO₄]_∞ ( 1 ), {[Ag(4,4′‐bipy)(CF₃SO₃)] ? CH₃CN}_∞ ( 2 ), {[Ag(4,4′‐bipy)(CH₃CN)]ClO₄ ? 0.5 CH₃CN}_∞ ( 3 ), metal‐free anbp ( 4 ), [Ag(anbp)NO₃(H₂O)]_∞ ( 5 ), {[Cd(4,4′‐bipy)₂(H₂O)₂](NO₃)₂ ? 4 H₂O}_∞ ( 6 ) and {[Zn(4,4′‐bipy)SO₄(H₂O)₃] ? 2 H₂O}_∞ ( 7 ) are reported.     

[2+4] and [2+2] Cycloaddition Reactions of N‐Sulfinyl Carboxylic Acid Amides with (CF3)2BNMe2. Crystal Structure of cyclo‐(CF3)2B‐NMe2‐S(=O)‐N=C(p‐CH3C6H4)‐O

N‐sulfinylacylamides R‐C(=O)‐N=S=O react with (CF₃)₂BNMe₂ ( 1 ) to form, by [2+4] cycloaddition, six‐membered rings cyclo‐(CF₃)₂B‐NMe₂‐S(=O)‐N=C(R)‐O for R = Me ( 2 ), t‐Bu ( 3 ), C₆H₅ ( 4 ), and p‐CH₃C₆H₄ ( 5 ) while N‐sulfinylcarbamic acid esters R‐O‐C(=O)‐N=S=O react with 1 to yield mixtures of six‐membered (cyclo‐(CF₃)₂B‐NMe₂‐S(=O)‐N=C(OR)‐O) and four‐membered rings (cyclo‐(CF₃)₂B‐NMe₂‐S(=O)‐N(C=O)OR) for R = Me ( 6 and 9 ), Et ( 7 and 10 ), and C₆H₅ ( 8 and 11 ). The structure of 5 has been determined by X‐ray diffraction.     

Kinetic and mechanistic investigation into the influence of chelate substituents on the substitution reactions of platinum(II) terpyridine complexes

The substitution kinetics of the complexes [Pt{4′‐(o‐CH₃‐Ph)‐terpy} Cl]SbF₆ (CH₃PhPtCl(Sb)), [Pt{4′‐(o‐CH₃‐Ph)‐terpy}Cl]CF₃SO₃ (CH₃PhPtCl(CF)), [Pt(4′‐Ph‐terpy)Cl]SbF₆ (PhPtCl), [Pt(terpy)Cl]Cl·2H₂O (PtCl), [Pt{4′‐(o‐Cl‐Ph)‐terpy}Cl]SbF₆ (ClPhPtCl), and [Pt{4′‐(o‐CF₃‐Ph)‐terpy}Cl]SbF₆ (CF₃PhPtCl), where terpy is 2,2′:6′,2″‐terpyridine, with the nucleophiles thiourea (TU), N,N′‐dimethylthiourea (DMTU), and N,N,N′,N′‐tetramethylthiourea (TMTU) were investigated in methanol as a solvent. The substitution reactions of the chloride displacement from the metal complexes by the nucleophiles were investigated as a function of nucleophile concentration and temperature under pseudo‐first‐order conditions using the stopped‐flow technique. The reactions followed the simple rate law k_obs = k₂[Nu]. The results indicate that the introduction of substituents in the ortho position of the phenyl group on the ancillary ring of the terpy unit does influence the extent of π‐backbonding in the terpy ring. This controls the electrophilicity of the platinum center, which in turn controls the lability of the chloro‐leaving group. The strength of the electron‐donating or ‐withdrawing ability of the substituents correlates with the reactivity of the complexes. Electron‐donating substituents decrease the rate of substitution, whereas electron‐withdrawing substituents increase the rate of substitution. This was supported by DFT calculations at the B3LYP/LACVP+** level of theory, which showed that most of the electron density of the HOMO is concentrated on the phenyl ligand rather than on the metal center in the case of the strongest electron‐withdrawing substituent in CF₃PhPtCl. The opposite was found to be true with the strongest electron‐donating substituent in CH₃PhPtCl. Thiourea was found to be the best nucleophile with N,N,N′,N′‐tetramethylthiourea being the weakest due to steric effects. The temperature dependence studies support an associative mode of activation. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 808–818, 2008     

Snapshots of the Hydrolysis of the Lithium Alkoxide [Li{OC(CF3)3}]4

Exposure of the tetrameric, heterocubane‐like perfluorinated lithium alkoxide [Li{OC(CF₃)₃}]₄ to humid air gaverise to the hydrolysis products [{(CF₃)₃CO}Li(H₂O)₂‐μ‐(H₂O)‐Li(H₂O)₂{OC(CF₃)₃}], [{(CF₃)₃CO}Li(H₂O)₂‐μ‐(H₂O)‐Li‐(H₂O)₃]⁺[OC(CF₃)₃]^– and [Li(H₂O)₄]⁺[OC(CF₃)₃]^– because of stepwise addition of water molecules in a gas‐solid reaction without solvent. All compounds were studied by X‐ray crystallography and their solid‐state structures are strongly influenced by hydrogen bonding and fluorophilic interactions.     

Gold(I) and Gold(III) Trifluoromethyl Derivatives

Trifluoromethylation of AuCl₃ by using the Me₃SiCF₃/CsF system in THF and in the presence of [PPh₄]Br proceeds with partial reduction, yielding a mixture of [PPh₄][Au^I(CF₃)₂] ( 1′ ) and [PPh₄][Au^III(CF₃)₄] ( 2′ ) that can be adequately separated. An efficient method for the high‐yield synthesis of 1′ is also described. The molecular geometries of the homoleptic anions [Au^I(CF₃)₂]^? and [Au^III(CF₃)₄]^? in their salts 1′ and [NBu₄][Au^III(CF₃)₄] ( 2 ) have been established by X‐ray diffraction methods. Compound 1′ oxidatively adds halogens, X₂, furnishing [PPh₄][Au^III(CF₃)₂X₂] (X=Cl ( 3 ), Br ( 4 ), I ( 5 )), which are assigned a trans stereochemistry. Attempts to activate C? F bonds in the gold(III) derivative 2′ by reaction with Lewis acids under different conditions either failed or only gave complex mixtures. On the other hand, treatment of the gold(I) derivative 1′ with BF₃?OEt₂ under mild conditions cleanly afforded the carbonyl derivative [Au^I(CF₃)(CO)] ( 6 ), which can be isolated as an extremely moisture‐sensitive light yellow crystalline solid. In the solid state, each linear F₃C‐Au‐CO molecule weakly interacts with three symmetry‐related neighbors yielding an extended 3D network of aurophilic interactions (Au???Au=345.9(1) pm). The high $\tilde \nu $ _CO value (2194 cm^?1 in the solid state and 2180 cm^?1 in CH₂Cl₂ solution) denotes that CO is acting as a mainly σ‐donor ligand and confirms the role of the CF₃ group as an electron‐withdrawing ligand in organometallic chemistry. Compound 6 can be considered as a convenient synthon of the “Au^I(CF₃)” fragment, as it reacts with a number of neutral ligands L, giving rise to the corresponding [Au^I(CF₃)(L)] compounds (L=CNtBu ( 7 ), NCMe ( 8 ), py ( 9 ), tht ( 10 )).     

Two new soluble iron–oxo complexes: [Fe2(μ‐O)(μ‐O2CCF3)2(O2CCF3)2(C10H8N2)2] and [Fe4(μ3‐O)2(μ‐O2CCF3)6(O2CCF3)2(C10H8N2)2]·CF3CO2H

Two new iron–oxo clusters, viz. di‐μ‐tri­fluoro­acetato‐μ‐oxo‐bis­[(2,2′‐bi­pyridine‐κ²N,N′)(tri­fluoro­acetato‐κO)­iron(III)], [Fe₂O(CF₃CO₂)₄(C₁₀H₈N₂)₂], and bis(2,2′‐bi­pyridine)­di‐μ₃‐oxo‐hexa‐μ‐tri­fluoro­acetato‐bis­(tri­fluoro­acetato)­tetrairon(III) tri­fluoro­acetic acid solvate, [Fe₄O₂(CF₃CO₂)₈(C₁₀H₈N₂)₂]·CF₃CO₂H, contain dinuclear and tetranuclear Fe^III cores, respectively. The Fe^III atoms are in distorted octahedral environments in both compounds and are linked by oxide and tri­fluoro­acetate ions. The tri­fluoro­acetate ions are either bridging (bidentate) or coordinated to the Fe^III atoms via one O atom only. The fluorinated peripheries enhance the solubility of these compounds. Formal charges for all the Fe centers were assigned by summing valences of the chemical bonds to the Fe^III atom.     

A Conformationally Flexible Dinuclear PtII Complex with Differential Behavior of its Two States toward Quadruplex DNA

The reaction of tetrakis(pyridine‐2‐yl)pyrazine (tppz) with 2 equiv of (2,2′‐bpy)Pt^II in water yields two isomeric dinuclear cations, [{Pt(2,2′‐bpy)}₂(tppz)]⁴⁺, in which Pt coordination exclusively takes place through the two pairs of pyridine‐2‐yl nitrogen atoms. The two conformational isomers differ in their overall shape, with the formation of “Z” and “U” shapes, which are formed at 40 °C (Z isomer, 1 ) and under reflux conditions (U isomer, 2 ), respectively. X‐ray crystal‐structure analyses of the Z isomer, [{Pt(2,2′‐bpy)}₂(tppz)](PF₆)₄ ? 3 CHCl₃ ? 4 H₂O ( 1 a ), and of the U isomer, [{Pt(2,2′‐bpy)}₂](PF₆)₄ ? 2 CH₃CN ? 1.5 H₂O ( 2 a ), were carried out. Co‐crystallization of compound 2 with PtCl₂(2,2′‐bpy) yielded [{Pt(2,2′‐bpy)}₂(tppz)](BF₄)₄?[PtCl₂(2,2′‐bpy)] ? 4.5 H₂O ( 3 ), in which the PtCl₂(2,2′‐bpy) entity was sandwiched between the two 2,2′‐bpy faces of the U‐shaped cation ( 2 ). Quantum chemical calculations revealed that the U isomer was more stable than the Z isomer, both in the gas phase and in an aqueous environment. These two isomers display different affinities toward duplex DNA and human telomeric quadruplex DNA (Htelo), as concluded from CD spectroscopy and FID assays. Thus, the U isomer binds significantly more strongly to quadruplex DNA (DC₅₀=0.38 μM ) than the Z isomer (DC₅₀=8.50 μM ).     

Enhancement of the biochemical activity of some market antibiotics by chemical modification: Synthesis,characterization, and biochemical evaluation

The reaction of isatin with the Ampicillin gave the new compound: (6R)‐3,3‐dimethyl‐7‐oxo‐6‐(2‐(([E]‐2‐oxoindolin‐3‐ylidene)amino)‐2‐phenylacetamido)‐4‐thia‐1‐azabicyclo[3.2.0]hept ‐ane‐2‐carboxylic acid (HAI). The new complexes derived from HAI and Co(II), Ni(II), Cu(II), Eu(III), and Gd(III) were obtained in pure form. The obtained compounds were characterized by elemental analysis, FTIR, UV–Vis, Fluorescence, ¹HNMR, Mass spectra, DTA, TGA, Magnetic susceptibility, X‐ray, AAS, and the conductivity of 0.001 M in DMSO. The obtained data indicated the formation of the target complexes: [Co(HAI)(H₂O)(NO₃)]NO₃.4H₂O, [Ni(AI)(H₂O)₂]Cl.2H₂O, [Cu(AI)]Cl.H₂O, [Eu(AI)(H₂O)Cl]Cl.5H₂O and [Gd(AI)(H₂O)(NO₃)]NO₃.3H₂O. The ligation sites were predicted from the guide of the FTIR and thermal analysis meanwhile the stereochemistry was proved by the UV–Vis and magnetic moment. Co(II) and Ni(II) gave an octahedral structure while Cu(II) gave a square planar form. Molecular modeling, molecular mechanics, and DFT calculations were carried out for the synthesized compounds. The active lone pair and surface properties were obtained and discussed in the silico level. The x‐ray analysis indicates the nanoparticle behavior of the Cu‐AI complex with a monoclinic structure. The interactions of the synthesized complexes with FM‐DNA moiety were investigated through spectrometric titration (UV–vis. spectra) and by using fluorescence spectroscopy. The modes and binding affinities were evaluated and discussed using Benesi–Hildebrand method. Antimicrobial activities of the synthesized compounds have been screened using the disc diffusion method. HAI and Cu‐AI gave activity exceeded the Ampicillin. The docking work was carried using the targeting protein of Escherichia coli FabH (PDB code: 1HNJ). The obtained binding energy was compared and discussed in terms of the in vitro studies.     

Aggregation Effects in Visible‐Light Flavin Photocatalysts: Synthesis,Structure, and Catalytic Activity of 10‐Arylflavins

A series of 10‐arylflavins (10‐phenyl‐, 10‐(2′,6′‐dimethylphenyl)‐, 10‐(2′,6′‐diethylphenyl)‐, 10‐(2′,6′‐diisopropylphenyl)‐, 10‐(2′‐tert‐butylphenyl)‐, and 10‐(2′,6′‐dimethylphenyl)‐3‐methylisoalloxazine ( 2 a – f )) was prepared as potentially nonaggregating flavin photocatalysts. The investigation of their structures in the crystalline phase combined with ¹H‐DOSY NMR spectroscopic experiments in CD₃CN, CD₃CN/D₂O (1:1), and D₂O confirm the decreased ability of 10‐arylflavins 2 to form aggregates relative to tetra‐O‐acetyl riboflavin ( 1 ). 10‐Arylflavins 2 a – d do not interact by π–π interactions, which are restricted by the 10‐phenyl ring oriented perpendicularly to the isoalloxazine skeleton. On the other hand, N3? H???O hydrogen bonds were detected in their crystal structures. In the structure of 10‐aryl‐3‐methylflavin ( 2 f ) with a substituted N3 position, weak C? H???O bonds and weak π–π interactions were found. 10‐Arylflavins 2 were tested as photoredox catalysts for the aerial oxidation of 4‐methoxybenzyl alcohol to the corresponding aldehyde (model reaction), thus showing higher efficiency relative to 1 . The quantum yields of 4‐methoxybenzyl alcohol oxidation reactions mediated by arylflavins 2 were higher by almost one order of magnitude relative to values in the presence of 1 .     

Synthesis,characterization, DNA binding,apoptosis and molecular docking of three Mn(II), Zn(II) and Cu(II) complexes with terpyridine‐based carboxylic acid

A series of novel cytotoxic compounds, [Mn(cpt)₂], [Zn(tpt)(H₂O)₂]?DMA?2(H₂O) and [Cu(tpt)]?DMA (cpt = 4′‐(4‐carboxyphenyl)‐2,2′:6′,2″‐terpyridine, tpt = 4‐(2,4,6‐tricarboxylphenyl)‐2,2′:6′,2″‐terpyridine, DMA = (CH₃)₂NH), were isolated and characterized. The structures of these complexes were characterized using single‐crystal X‐ray diffraction. The mode and extent of binding between fish sperm DNA and the complexes were investigated using fluorescence spectroscopy and molecular docking. These results indicate the ability of the complexes to bind to DNA with different binding affinities. The binding of the Zn(II) complex with DNA is stronger than that of the corresponding Cu(II) analogue, which is expected due to the z* effect and geometry. The ability of these complexes to cleave pBR322 plasmid DNA was demonstrated using gel electrophoresis assay, showing that the complexes have effective DNA cleavage activity. In addition, the cytotoxic effects of these complexes were examined on HeLa cells (human cervix epithelia carcinoma cells) in vitro. The three complexes exhibit different cytotoxic effects and decent cancer cell inhibitory rate. This means that the structures and type of metal have a great influence on the activity of these novel complexes.     

Acid‐, Water‐ and High‐Temperature‐Stable Ruthenium Complexes for the Total Catalytic Deoxygenation of Glycerol to Propane

The ruthenium aqua complexes [Ru(H₂O)₂(bipy)₂](OTf)₂, [cis‐Ru(6,6′‐Cl₂‐bipy)₂(OH₂)₂](OTf)₂, [Ru(H₂O)₂(phen)₂](OTf)₂, [Ru(H₂O)₃(2,2′:6′,2′′‐terpy)](OTf)₂ and [Ru(H₂O)₃(Phterpy)](OTf)₂ (bipy=2,2′‐bipyridine; OTf^?=triflate; phen=phenanthroline; terpy= terpyridine; Phterpy=4′‐phenyl‐2,2′:6′,2′′‐terpyridine) are water‐ and acid‐stable catalysts for the hydrogenation of aldehydes and ketones in sulfolane solution. In the presence of HOS(O)₂CF₃ (triflic acid) as a dehydration co‐catalyst they directly convert 1,2‐hexanediol to n‐hexanol and hexane. The terpyridine complexes are stable and active as catalysts at temperatures ≥250 °C and in either aqueous sulfolane solution or pure water convert glycerol into n‐propanol and ultimately propane as the final reaction product in up to quantitative yield. For the terpy complexes the active catalyst is postulated to be a carbonyl species [(4′‐R‐2,2′:6′,2′′‐terpy)Ru(CO)(H₂O)₂](OTf)₂ (R=H, Ph) formed by the decarbonylation of aldehydes (hexanal for 1,2‐hexanediol and 3‐hydroxypropanal for glycerol) generated in the reaction mixture through acid‐catalyzed dehydration. The structure of the dimeric complex [{(4′‐phenyl‐2,2′:6′,2′′‐terpy)Ru(CO)}₂(μ‐OCH₃)₂](OTf)₂ has been determined by single crystal X‐ray crystallography (Space group P (a=8.2532(17); b=12.858(3); c=14.363(3) Å; α=64.38(3); β=77.26(3); γ = 87.12(3)°, R=4.36 %).     

Kinetics and mechanism of the thermal gas‐phase oxidation of perfluorobutene‐2 in presence of trifluoromethyl hypofluorite

The oxidation of perfluorobutene‐2 (C₄F₈) initiated by trifluoromethyl hypofluorite (CF₃OF) in presence of O₂ has been studied at 323.1, 332.6, 342.5, and 352.0 K, using a conventional static system. The initial pressure of CF₃OF was varied between 4.8 and 23.6 Torr, that of C₄F₈ between 48.7 and 302.4 Torr, and that of O₂ between 51.5 and 270.4 Torr. Several runs were made in presence of 325.5–451.2 Torr of N₂. The main products were COF₂, CF₃C(O)F, and CF₃OC(O)F. Small amounts of compound containing ? CF(CF₃)? O? C(O)CF₃ group were also formed, as detected by ¹³C NMR spectroscopy. The oxidation is a homogeneous short‐chain reaction, attaining, at the pressure of O₂ used, the pseudo‐zero‐order condition with respect to O₂ as reactant. The reaction is independent of the total pressure. Its basic steps are as follows: the thermal generation of CF₃O^? radicals by the abstraction of fluorine atom of CF₃OF by C₄F₈, the addition of CF₃O^? to the alkene, the formation of perfluoroalkoxy radicals RO^? in presence of O₂, and the decomposition of these radicals via the C? C bond scission, giving products containing ? C(O)F end group and reforming RO^? and CF₃O^? radicals. The mechanism consistent with experimental results is postulated. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 532–541, 2003     

Preparation and Structure of [Me3N(CF3)2BCCB(CF3)2NMe3]

Bis‐trimethylamine‐ethynyl‐di‐bis(trifluoromethyl)borane [Me₃N(CF₃)₂BCCB(CF₃)₂NMe₃] ( 1 ) has been prepared from trimethylamine‐ethynyl‐bis(trifluoromethyl)borane, [HCCB(CF₃)₂NMe₃], and dimethylamino‐bis(trifluoromethyl)borane, (CF₃)₂BNMe₂. The structure of 1 has been determined by x‐ray crystallography. In the solid state the molecule possesses crystallographic C_i symmetry. The acetylenic attachment to the boron atom is characterized by a short B–C bond length of 1.565(4) Å and an essentially linear B–C–C′ bond angle of 178.1(4)°.