Synthesis,characterization and biological properties of novel ON donor bidentate Schiff bases and their copper(II) complexes

Four novel ON donor Schiff bases (E)-3-((4-phenoxyphenylimino)methyl)benzene-1,2-diol (HL₁),(E)-3-((4-(4-biphenyloxy)phenyliminomethyl)benzene-1,2-diol (HL₂), (E)-3-((4-naphthoxyphenylimino)methyl)benzene-1,2-diol (HL₃), (E)-3-((4-(2-naphthoxy)phenylimino)methyl)benzene-1,2-diol (HL₄) and their copper(II) complexes bis((E)-3-((4-phenoxyphenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₁)₂) bis((E)-3-((4-(4-biphenyloxy)phenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₂)₂), bis((E)-3-((4-naphthoxyphenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₃)₂), bis((E)-3-((4-(2-naphthoxy)phenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L₄)₂) have been synthesized and characterized by spectroscopic (FTIR, NMR, UV–visible) and elemental analysis. The crystal structures of HL₁, HL₂, HL_3, and HL₄ have been determined, which reveal intramolecular N-H?O (HL₁, HL₂, HL_3, and HL₄) hydrogen bonds in the solid state. Keto-amine and enol-imine tautomerism is exhibited by the Schiff bases in solid and solution states. The Schiff bases and their copper(II) complexes have been screened for their biological activities. In antimicrobial assays (antibacterial and antifungal), HL₄ showed promising results against all strains through dual inhibition property while the rest of the compounds showed activity against selective strains. On the other hand, in cytotoxic, DPPH, and inhibition of hydroxyl (OH) free radical-induced DNA damage assays, the results were found significantly correlated with each other, i.e. the ligands HL₁ and HL₂ showed moderate activity while their complexes Cu(L₁)₂ and Cu(L₂)₂ exhibited prominent increase in activity. As the results of these assays are supporting each other, it represents the strong positive correlation and antioxidant nature of investigated compounds.     

An unexpected reaction between perfluoroisobutylene,caesium fluoride and haloforms

(CF₃)₂ CCF₂ reacts with CHCl, CHBr₃ and CHI₃ in the presence of CsF in diglyme, giving 3,3 - difluoro - 2 - halogeno - 4,4,5,5 - tetrakis(trifluoromethyl)cyclopent - 1 - enes. In the case of CHCl₃ the intermediate is shown to be 1,1 - dichloro - 3,3 - bis - (trifluoromethyl)allene (identified as an adduct with furan). 3,3 - Difluoro - 2 - chloro - 4,4,5,5 - tetrakis(trifluoromethyl)cyclopent - 1 - ene eliminates HCI under the action of CsF, giving a trimer of 3,3 - difluoro - 4,4,5,5 - tetrakis(trifluoromethyl)cyclopent - 1 - yne, namely, perfluorocarbon C₂₇F₄₂ (a Dewar benzene derivative).     

Synthesis and polymerization of some optically active 2- and 1,2-substituted butadienes

Dehydration of (S)-3,5-dimethyl-1-hepten-3-ol gave: (3E)- (I) and (3Z)-(5S)-3,5-dimethyl-1,3-heptadienes (II) and 2-[(S)- 2-methylbutyl]-1,3-butadiene (III). 2-[(S)-1-Methylpropyl]-1,3-butadiene (IV) was also prepared similarly by dehydration of (S)-3,4-dimethyl-1-hexene-3-ol. Monomers I–IV we polymerized in the presence of the TiCl₄–Al(i-C₄H₉)₃ catalyst system and in emulsion with K₂S₂O₈ as initiator. Monomer IV was also polymerized in the presence of butyllithium. Specific rotations of polymers are of the same order of magnitude as that of monomers, with exception of polymers prepared by stereospecific polymerization of (S)-I and (S)-II. The acetone-soluble fraction of these polymers has a molar rotation similar to that of monomer, while the acetone-insoluble part has a lower rotation ([M]_D of monomer +53.2°; [M]_D of polymer, +5.9°).     

Pentamethylcyclopentadienyl rhodium complexes of 1,5- and 1,7-dihydro-s-indacenes and their derivatives

The reaction of (C₅Me₅RhCl₂)₂ with AgSbF₆ in the presence of 1,5- and 1,7- dihydro-s-indacenes or 2,6-dimethyl-1,5- and 1,7-dihydro-s-indacenes provides stable η⁵- or η⁶-monorhodium complexes, respectively. A novel phane rhodium complex is described.     

Synthesis and Structures of Silver(I) and Copper(I) 3,5-Dipentyl-1,2,4-Triazolates

The Ag(I) and Cu(I) complexes of 4-amino-3,5-dipentyl-4H-1,2,4-triazole (4-NH₂-3,5-(C₅H₁₁)₂tz) and 3,5-dipentyl-1H-1,2,4-triazole (3,5-(C₅H₁₁)₂tzH) have been synthesized and characterized. X-Ray analysis shows that {Ag₄[4-NH₂-3,5-(C₅H₁₁)₂tz]₆}(BF₄)₄ is a tetranuclear complex featuring an Ag₄tz₆ cluster; {Ag[3,5-(C₅H₁₁)₂tz]}_n exhibits a 3D structure of lvt-a topology; and {Cu₂[3,5-(C₅H₁₁)₂tz]Br}_n is a Cu₄Br₄-cluster based 3D complex with the dia topology.     

Polyfluorophenyl acetylenes and related compounds

From the reaction of pentafluoro- and 4-substituted-tetrafluoroiodobenzene (the substituent group R being CF₃-, H-, CH₃- or CH₃O-) with copper(I) 3-(2′-tetrahydropyranyloxy)prop-1-ynide has been obtained the corresponding 3-(polyfluorophenyl) prop-2-ynol derivative. Where R = N(CH₃)₂- and NH₂- the acetylenic alcohol was not obtained; these were synthesized by the reaction of dimethylamine and ammonia with 3-(pentafluorophenyl)prop2-ynol itself. The acetylenic alcohols were converted to the corresponding polyfluorophenyl acetylenes by nickel peroxide in dioxan/aqueous NaOH. With benzene at 60° as solvent 3-(pentafluorophenyl)prop-2-ynol was oxidized to the aldehyde and acid and in refluxing benzene, 1-4bis(polyfluorophenyl)butadiynes and polyfluorophenyl acetylenes were obtained. The mechanism of some of the reactions has been discussed.     

Synthesis,characterization, and electrochemical study of two new macroacyclic Schiff bases and their copper(II) and zinc(II) complexes

Two new potentially octadentate N₂O₆ Schiff-base ligands 2-((E)-(2-(2-(2-((E)-2-hydroxy-3-methoxybenzylideneamino)phenoxy)phenoxy)phenylimino)methyl)-6-methoxyphenol H₂L¹ and 2-((E)-(2-(2-(2-((E)-2-hydroxy-3-methoxybenzylideneamino)phenoxy)-4-tert-butylphenoxy)phenylimino)methyl)-6-methoxyphenol H₂L² were prepared from the reaction of O-Vaniline with 1,2-bis(2′-aminophenoxy)benzene or 1,2-bis(2′-aminophenoxy)-4-t-butylbenzene, respectively. Reactions of H₂L¹ and H₂L² with copper(II) and zinc(II) salts in methanol in the presence of N(Et)₃ gave neutral [CuL¹]?·?0.5CH₂Cl₂, [CuL²], [ZnL¹]?·?0.5CH₂Cl₂, and [ZnL²] complexes. The complexes were characterized by IR spectra, elemental analysis, magnetic susceptibility, ESI–MS spectra, molar conductance (Λ_m), UV-Vis spectra and, in the case of [ZnL¹]?·?0.5CH₂Cl₂ and [ZnL²], with ¹H- and ¹³C-NMR. The crystal structure of [ZnL¹]?·?0.5CH₂Cl₂ has also been determined showing the metal ion in a highly distorted trigonal bipyramidal geometry. The electrochemical behavior of H₂L² and its Cu(II) complex, [CuL²], was studied and the formation constant of [CuL²] was evaluated using cyclic voltammetry. The logarithm value of formation constant of [CuL²] is 21.9.     

Transition metal 1,2-bidentate thiolates as building blocks and their construction into cluster complexes

Simple fragments of transition metal 1,2-bidentate thiolates, the so-called building blocks of the general compositions ML₃, ML₂, ML, M(O)L₂, ML₂L, MLL, etc. have been proposed to constitute the di-, tri- and tetranuclear complexes concerned in this review. Structureal regularities and characteristics have been discussed and summarized according to the thiolato ligands edt and pdt, bdt and tdt, mp, and mpo, and mpp, respectively.Abbreviations H₂mpo o-mercaptophenol - Hmpo 2-mercaptopyridine-N-oxide - R₂dtc N,N-dialkyldithiocarbamate - Haet 2-aminoethanethiol - H₂bdt o-benzenedithiol - H₂pdt 1,2-propanedithiol - H₂tdt toluene-3,4-dithiol - Hmpp-mppH bis-(3-hydroxy-2-pyridyl)disulfide - Hmp-mpH bis-(2-oxyphenyl)disulfide - H₂edt 1,2-ethanedithiol - dppe 1,2-bis(diphenylphosphino)ethane - H₂tedt 3,4,5,6-tetrachlorobenzene-1,2-dithiol - H₂tpdt 3-thiapentane-1,5-dithiol - H₂mnt maleonitriledithiol - Him imidazole - Bz benzyl - py pyridine     

Tetraphenylbismuth aroxides: Synthesis and structure

Tetraphenylbismuth aroxides Ph4BiOAr (Ar = C₆H₃Cl₂-2,6, C₆H₂(Br₂-2,6)(t-Bu)-4, C₆H₂(Br₂-2,6)(NO₂)-4 · 1/2C₆H₆, C₆H₃(NO₂)₂-2,4, C₆H₂(NO₂)₃-2,4,6) were synthesized in the yield up to 90% by the reaction of pentaphenylbismuth with phenols and triphenylbismuth diaroxides and studied by X-ray diffraction. The Bi atoms of tetraphenylbismuth aroxides have a distorted trigonal-bipyramidal coordination with the axial O atom of the aroxide group. The axial angles CBiO vary from 171.7(2)° to 179.3(3)°. The distances Bi-O change in the interval 2.453(2)–2.925(7) Å depending on the nature of substituents in the aromatic ring of the phenol residue. The increasing distance Bi-O in the series of compounds under study correlates with the tendency of the BiC₄ fragment to form the tetrahedral configuration.     

一种新型无粘结剂电极的制备及电吸附脱盐性能研究

以椴木为前驱体、二氧化碳为活化剂,制备出具有一定强度、无需粘结剂的电极材料,同时可用作集流体。通过扫描电镜、X射线衍射、拉曼光谱和孔径分析等对材料的形貌和孔结构进行了分析,并使用电吸附脱盐装置测试了其电吸附脱盐性能。结果表明,该材料有大量的微孔结构,比表面积为1440m2/g,其电吸附脱盐能力随着溶液浓度的提高而升高,在溶液浓度为200、500、1000和2000 mg/L时,吸附量分别为2. 02、3. 76、6. 21和12. 42 mg/g。     

Noble-Gas Difluoride Complexes of MOF4 (M=Mo,W); Syntheses,Structures and Bonding of NgF2 ⋅ MOF4 and XeF2 ⋅ 2MOF4 (Ng=Kr,Xe)

The NgF₂ ⋅ MOF₄ (Ng=Kr, Xe; M=Mo, W) and XeF₂ ⋅ 2MOF₄ complexes were synthesized in anhydrous HF (aHF) solvent and melts, respectively. Their single-crystal X-ray diffraction (SCXRD) structures show NgF₂ ⋅ MOF₄ and XeF₂ ⋅ 2MOF₄ have F_t−Ng−F_b- - -M arrangements, in which the NgF₂ ligands coordinate to MOF₄ through Ng−F_b- - -M bridges. The XeF₂ ligands of XeF₂ ⋅ 2MOF₄ also coordinate to F₃OM−F_b’- - -M'OF₄ moieties through Xe−F_b- - -M bridges to form F_t−Xe−F_b- - -M(OF₃)−F_b’- - -M'OF₄, where XeF₂ coordinates trans to the M=O bond and F_b’ coordinates trans to the M’=O bond. The Ng−F_t, Ng−F_b, and M- - -F_b bond lengths of NgF₂ ⋅ nMOF₄ are consistent with MOF₄ and F₃OM−F_b’- - -M'OF₄ fluoride-ion affinity trends: CrOF₄<MoOF₄<WOF₄≈F₃OMo−F_b’- - -Mo'OF₄<F₃OW−F_b’- - -W'OF₄. The [- -(F₄OMo)(μ₃-F)H- - -(μ-F)H- -]_∞ solvate was also synthesized in aHF and characterized by SCXRD. Quantum-chemical calculations show the M- - -F_b bonds of NgF₂ ⋅ MOF₄ and XeF₂ ⋅ 2MOF₄ are predominantly electrostatic, σ-hole type bonds.     

Rhodathiaboranes with `anomalous' electron counts: synthesis, structure and reactivity

Analysis of the structures of 8,8-(PPh₃)₂-8,7-nido-RhSB₉H₁₀ and 9,9-(PPh₃)₂-9,7,8-nido-RhC₂B₈H₁₁ by RMS misfit calculations has confirmed that these rhodaheteroboranes possess nido 11-vertex cluster geometries in apparent contravention of Wade's rules. However, examination of the molecular structures of both species shows that the {RhP₂} planes are inclined by ca. 66° with respect to the metal-bonded SB₃ or CB₃ faces, and that two weak ortho-CHRh agostic interactions occupy the vacant co-ordination position thereby created. As a consequence of these agostic bonds the Rh atom, and hence the overall cluster, is provided with an additional electron pair, meaning that their nido structures are now fully consistent with Wade's rules. The chelated diphosphine compound 8,8-(dppe)-8,7-nido-RhSB₉H₁₀ is similar to the PPh₃ compound in showing the same agostic bonding. Attempts to prepare a bis-P(OMe)₃ analogue result in ligand scavenging and the formation of 8,8,8-{P(OMe)₃}₃-8,7-nido-RhSB₉H₁₀. Similarly, reaction between Cs[6-arachno-SB₉H₁₂] and RhCl(dmpe)CO does not result in CO loss but in formation of 8,8-(dmpe)-8-(CO)-8,7-nido-RhSB₉H₁₀, shown to exist as a mixture of two of three possible rotamers. Deprotonation of 8,8-(PPh₃)₂-8,7-nido-RhSB₉H₁₀ and 8,8-(dppe)-8,7-nido-RhSB₉H₁₀ with MeLi yields the anions [1,1-(PPh₃)₂-1,2-closo-RhSB₉H₉]⁻ and [1,1-dppe-1,2-closo-RhSB₉H₉]⁻, respectively, with octadecahedral cage structures. It is argued that anion formation causes the agostic bonding to be `switched-off' and results in the cluster adopting the closo architecture predicted by Wade's rules. This structural change is fully reversible on reprotonation, and if reprotonation of [1,1-(dppe)-1,2-closo-RhSB₉H₉]⁻ is carried out in MeCN, the product 8,8-(dppe)-8-(MeCN)-8,7-nido-RhSB₉H₁₀ forms. Interestingly, 8,8-(dppe)-8-(MeCN)-8,7-nido-RhSB₉H₁₀ reconverts to 8,8-(dppe)-8,7-nido-RhSB₉H₁₀ on standing in CDCl₃, suggesting that the agostic bonding is sufficiently strong to displace co-ordinated MeCN. All new compounds are fully characterised by multinuclear NMR spectroscopy and, in many cases, by single crystal X-ray diffraction.     

The reactions of 2-[(dimethylamino)methyl]phenylcopper and -lithium tetramer with cuprous and cupric halides

2-[(Dimethylamino)methyl]phenylcopper tetramer (R₄Cu₄) forms a red $\text{1}\text{1}$ complex (RCu - CuBr)_n with cuprous bromide. The $\text{1}\text{1}$ interaction of 2-[(dimethylamino)methyl]phenylcopper with cupric halides results in the formation of the dimer RR, the 2-halo-substituted benzylamine R—Halide and minor amounts of N,N-dimethylbenzylamine RH. The formation of these products can be explained on the basis of an intramolecular electron-transfer redox reaction taking place in innersphere activated complexes of the type R₄Cu₃Cu - - - X - - - Cu^IIX(Cu^IIX₂)_n-1. The course of the metathesis reaction of 2-[(dimethylamino)methyl]phenyllithium with cuprous bromide depends on the order of addition of the reactants. Reversed addition (RLi to CuBr) results in the formation of an inseparable mixture of complexes of the type (RCu)_x- (CuBr)_y. Upon addition of CuBr to RLi the uncomplexed organocopper compound R₄Cu₄ is formed.     

Unprecedented and Effective Synthesis of Thiazolines from Perfluoro-3-isothiocyanato-2-methyl-2-pentene and Certain P-Nucleofuges

The reactions of perfluoro-3-isothiocyanato-2-methyl-2-pentene with PPh₃ and P(NEt₂)₃ in the presence of NaBF₄, KI, and NaBPh4 form phosphonium salts with the heterocyclic substituent (4E)-5,5-bis(trifluoromethyl)-4-(tetrafluoroethylidene)-4,5-dihydro-1,3-thiazol-2-yl, instead of involving desulfurization and formation of P-F-containing products. The reaction with tris(pentafluorophenyl)phosphine fails. The reactions with P(OEt)₃ in the presence of ClSiMe₃ or (CH₃O)₂POSiMe₃ yield diethyl or dimethyl [(4E)-5,5-bis(trifluoromethyl)-4-(tetrafluoroethylidene)-4,5-dihydro-1,3-thiazol-2-yl]phosphonates and no intramolecular alkylation products. The ¹H, ¹³C, ¹⁹F, and ³¹P spectra are presented, and the reaction pathways are discussed. Potential mechanisms of the biological and catalytic activity of the reaction products are considered.     

Preparation of optically active flowery and woody-like odorant ketones via Corey-Chaykovsky oxiranylation: Irones and analogues

α-, β-, and γ-Irones and analogues have been prepared from optically active ketones (+)- 1 , (+)- 6a,b , and (+)- 17 , via a Corey-Chaykovsky oxiranylation (Me₂S, Me₂SO₄, Me₂SO, NaOH) followed by isomerisation (SnCl₄ or MgBr₂). (+)-Dihydrocyclocitral ( 19a ), obtained from (?)-citronellal, and analogue (+)- 19b , were condensed with various ketones to afford (+)- 21a–f , and after hydrogenation (+)- 22a–f. A mild oxidative degradation of aldehydes (+)-trans-and (?)-cis- 8a,b , to ketones (?)- 16a,b , as well as olfactive evaluations, ¹³C-NMR assignments, and absolute configurations of the intermediate epoxides, aldehydes, and alcohols are presented.     

Optimization of the synthesis of phenanthrene-2- and -3-sulfonyl chlorides

Sulfonation of phenanthrene with sulfuric acid, followed by neutralization with sodium hydroxide, gave a mixture of isomeric sodium phenanthrenesulfonates in an overall yield of 83%. Sodium phenanthrene-2-, -3-, and -9-sulfonates were isolated in 17, 43, and 4% yield, respectively. Sulfonation of phenanthrene with ClSO₃H or SO₃ did not improve the yields of phenanthrene-2- and -3-sulfonic acids. Treatment of sodium phenanthrene-2- and -3-sulfonates with PCl₅-POCl₃ or SOCl₂-DMF afforded the corresponding sulfonyl chlorides in 89 and 87 or 69 and 70% yield, respectively. Pure phenanthrene-2- and -3-sulfonyl chlorides were also synthesized in 27 and 51% yield by reaction of a mixture of 2- and 3-sulfonates with PCl₅-POCl₃.     

Solubility and first hidrolysis constants of europium at different ionic strength and 303 K

The solubility of europium at 0.02M, 0.1M and 0.7M NaClO₄ ionic strength solutions was determined by a radiometric method and pEu_s-pC_H diagrams were obtained. Hydrolysis constants were also determined at the same ionic strengths by pH titration and the values found were log *₁ = -7.68±0.11, -8.07±0.10 and -8.20±0.11. The log K _sp values were -23.5±0.2, -22.7±0.2 and -21.9±0.2 for 0.02M, 0.1M and 0.7M NaClO₄ ionic strengths, respectively, at 303 K under CO₂-free conditions and the extrapolated value at zero ionic strength was log K _sp ⁰ = -24.15. The working pC_H ranges for the calculation of the hydrolysis constants were selected from the pEu_s-pC_H diagrams in the region where precipitation of europium oxide or hydroxide was less than 20%. Europium removal from aqueous solutions with zeolites was explored.     

New morpholine- and piperazine-functionalized triphenylantimony(V) catecholates: The spectroscopic and electrochemical studies

Novel functionalized triphenylantimony(V) catecholates - Ph₃Sb[4-O(CH₂CH₂)₂N-3,6-DBCat] (1), Ph₃Sb[4-PhN(CH₂CH₂)₂N-3,6-DBCat] (2), Ph₃Sb[4-Ph₂CHN(CH₂CH₂)₂N-3,6-DBCat] (3), Ph₃Sb[4,5-Piperaz-3,6-DBCat] (4) and binuclear bis-catecholate Ph₃Sb[3,6-DBCat-4-N(CH₂CH₂)₂N-4-3,6-DBCat]SbPh₃ (5) were synthesized by the oxidative addition reaction of corresponding o-quinones with triphenylantimony. The [4-O(CH₂CH₂)₂N-3,6-DBCat]²⁻, [4-PhN(CH₂CH₂)₂N-3,6-DBCat]²⁻, [4-Ph₂CHN(CH₂CH₂)₂N-3,6-DBCat]²⁻ and [4,5-Piperaz-3,6-DBCat]²⁻ are 4-(morpholin-1-yl)-, 4-(4-phenyl-piperazin-1-yl)-, 4-(4-dephenylmethyl-piperazin-1-yl)-, and 4,5-(piperazin-1,4-diyl)-3,6-di-tert-butyl-catecholate dianionic ligands, correspondingly. Complexes 1-5 were characterized in details by IR-, ¹H and ¹³C NMR spectroscopy and cyclic voltammometry. Molecular structure of 4·CH₃OH was determined by X-ray crystallography to be a distorted tetragonal-pyramidal. The NMR spectroscopic and electrochemical investigations of complexes in the presence of air reveal the reactions of complexes with dioxygen leading to the formation of spiroendoperoxides of 1,2,4,3-trioxastibolane type in a NMR yield of 25-37%.     

Chiroptical properties and conformation of some 2-alkyl substituted dicarboxylic acids

CD spectra in EPA (a mixture of ethanol, isopentane and diethyl ether) at 25° and -185° were measured for the following acids and their methyl esters: (R)-2-methyl-, (R)-2-ethyl-, (R)-2-n-propyl-, (R)-2-n-butyl-, (R)-2-n-hexyl-, (R)-2-isobutyl-, (S)-2-isopropyl- and (S)-2-cyclohexylsuccinic acids, (R)-2-methylglutaric acid, (R)-2-methylsuberic acid, (R,R)-2,3-dimethyl-succinic acid and (+)-trans-Caronic acid (3,3-dimethyl-1,2-cyclopropane-dicarboxylic acid). The CD data are explained in terms of the conformation around the C₁C₂, C₂C₃ and C₃C₄ bonds.     

The thermodynamic effect of fluorine as a substituent: Vinylic CF2 and CFH and allylic CF2C

I₂-catalyzed isomerizations of 3-fluoropropene and 3,3 - difluoropropene, and a Cope rearrangement of 1,1 - difluoro - 1,5 - hexadiene provide thermodynamic data which allow the determination of a number of important group values for contributions to ΔH^o_f which when combined with those determined in the preceding paper allow the calculations of ΔH^o_f's of most simple F-substituted hydrocarbons: [C_d(F)(H)] = ? 38.4, [C_d(F)₂] = ? 88.0, [C(F)₂(C)(C_d)] = ? 103.9, [C(F)₂(C)₂] = ? 104.9 kcal/mole. A kinetic study of the conversion of 1,1 - difluoro- to 3,3 - difluoro - 1,5 - hexadiene provided activation parameters for the process: Log A = 10.8, E_a = 33.0 kcal/mole and ΔS^≠ = ? 12.2 e.u. Incremental geminal stabilizations of F and other substituents are discussed and contrasted.