Palladium(II)-catalyzed Suzuki–Miyaura reactions of arylboronic acid with aryl halide in water in the presence of 4-(benzylthio)-N,N,N-trimethybenzenammonium chloride

This work reported that Suzuki–Miyaura coupling reactions of arylboronic acid with aryl bromide or iodides were mediated by Pd(OAc)₂ and 4-(benzylthio)-N,N,N-trimethylbenzenammonium chloride in the presence of Na₂CO₃ in water under the mild conditions. The corresponding Suzuki–Miyaura coupling products were obtained in good to excellent yields.     

IR,PMR and Mössbauer studies on the complexes of triphenyltin chloride and triphenyltin isothiocyanate with a series of N-alkylsalicylideneimines

Eleven new complexes of the type Ph₃SnX: o-HOC₆H₄CHNR (X = Cl, NCS; R = CH₃, t-Bu, PhCH₂, n-C₆H₁₃, c-C₆H₁₁, HOCH₂CH₂) have been synthesized by the reactions of triphenyltin chloride or isothiocyanate with the N-alkylsalicylideneimines. The complexes are non-electrolytes in nitrobenzene. IR, PMR and Mössbauer spectroscopic studies indicate that the ligands are behaving as monodentates via the phenolic oxygen atoms, and that the complexes all have trigonal bipyramidal geometry with the phenyl groups occupying the equatorial positions.     

Organic azo complexes of molybdenum and their reactions with electrophiles

Organic azo(1) and N,N-disubstituted hydrazido-N'(2) complexes of molybdenum have been prepared by the reactions of certain molybdenum-oxo complexes with hydrazines.     

Dioxouranium(VI) complexes of some sulphur donor ligands

Complexes of uranyl chloride and uranyl nitrate of the type UO₂X₂·2L and [UO₂X₂2L′], where X = Cl or NO₃ and L = N,N′-tetramethylthiourea (TMTU); N,N′-dimethylthiourea (DMTU); monomethylthiourea (MMTU), monoethylthiourea (METU), pyridine-2-thiol (PYT) and L′ = 4,6-dimethylpyrimidine-2-thiol (PYMT), have been prepared. The complexes were characterised on the basis of IR spectroscopy and by elemental analysis. In some cases Raman spectra are also reported.     

Electrochemical oxidation of several oxocarbon salts in N,N-dimethylformamide

The oxocarbon salts of croconic acid and its dicyanomethylene derivatives have been shown to undergo two consecutive reversible one-electron transfers in N,N-dimethylformamide to produce stable radical anions and the neutral croconates. Disproportion equilibrium constants were found to be quite small for all the crononate radical anions investigated. Following chemical reactions accompanied the second oxidation process of dicyanomethylene-substituted crononates. Substituent effects were shown to be ring position-independent and are discussed with respect to the unique resonance structure of the crononates.     

Heterogeneous electron-transfer kinetics for some multiply bonded dirhenium complexes

Standard electrochemical rate constants k^ex_ob have been measured for the two sequential one-electron oxidations of triply-bonded dirhenium(II) complexes Re₂X₄(PR₃)₄, where X = Cl or Br, and PR₃ = a monodentate tertiary phosphine, and also for allied complexes in methylene chloride, acetonitrile, and N,N-dimethylformamide at platinum electrodes. The objective is to explore the possible dependence of k^ex_ob upon the known differences in the structural changes accompanying electron transfer. Although significant and even substantial variations in k^ex_ob were observed for closely related redox couples, the reactivity trends appear to be chiefly a consequence of differences in electrostatic work terms at the metal/solution interface. Comparisons are made with recent results for mononuclear organometallic redox couples.     

Preparation and properties of the formamidino complexes [M(π-C5H5){HC(NR)2}(CO)2] (M = molybdenum or tungsten; R = aryl or alkyl)

The preparation and properties of the complexes [M(π-C₅H₅){HC(NR)₂}CO)₂] (M = Mo, W; R = aryl or alkyl) are reported. The complex [Mo(π-C₅H₅){HC(N-p-tolyl)₂}(CO)₂] could be prepared by (a) reaction of MoCp(CO)₃Cl with M′{HC(N-p-tolyl)₂} (M′ = K, Ag or Cu); (b) irradiation of MoCp(CO)₃Cl with HC(HN-p-tolyl)N-p-tolyl); and (c) reaction of [MoCp(CO)₃]₂ with M′{HC(N-p-tolyl)₂} (M′ = Ag or Cu). The several routes to this complex give indications of the mechanisms of formation. The structure of these complexes and the bonding nature of the metal with the formamidino group is discussed on basis of the ¹H and ¹³C NMR and IR spectra.Reaction of N,N′-dimethyl formamidine with MCp(CO)₃Cl gave the complex [M(π-C₅H₅){HC(NMe)N(CO)Me}(CO)₂], containing a carbonyl inserted between the metal and the formamidino group. Irradiation of this carbamoyl complex caused decarbonylation, yielding the complex [M(π-C₅H₅){HC(NMe)₂}CO)₂].     

Synthesis,characterization and study of antibacterial activity of enaminone complexes of zinc and iron

Complexes of enaminones; 4-N,N-diethylamine-pent-3-ene-2-one [HL¹], 4-N,N-di n-propylamine-pent-3-ene-2-one [HL²] and 4-N,N-dicyclohexylamine-pent-3-ene-2-one [HL³] with Fe(II) and Zn(II) ions were prepared by reacting the equimolar ethanolic solutions of the ligands (HL¹, HL² and HL³) with ethanolic metal solutions. The complexes formed, were characterized by infrared, ultraviolet and atomic absorption spectroscopy. Ligands and their metal complexes were tested against Escherichia coli and Staphylococcus aureus bacteria to assess their antibacterial action using disc diffusion method. Ligands were completely inactive against bacteria whereas the complex Zn (HL¹) has significant action on both bacteria, indicating that it has a good potential as bactericide. Other complexes have normal antiseptic character.     

Kinetics and mechanism of some fast anation reactions of a series of substituted dien complexes of palladium(II). Temperature and pressure dependencies in weakly acidic aqueous solution1

Anation reactions of the type [Pd(L)(H₂O)]²⁺ + X^? »[Pd(L)X]⁺ + H₂O with L = 1, 4, 7-Et₃dien, 1, 1, 7, 7-Me₄dien and 1, 1, 4, 7, 7-Me₅dien and X^? = Cl^?, Br^?, I^? and N₃? have been studied kinetically as a function of [X?], temperature and pressure (up to 1 kbar). Second-order anation rate constants decrease with an increase in the size of L, and are accompanied by an increase in ΔH≠. For a given L the sequence Cl^? < Br^? < I^? < N₃^? holds, and the values of ΔS≠ and ΔV≠ are consistent with an associative mechanism. The results are discussed with reference to similar anation reactions previously investigated.     

Synthese eines verbrückten π-allyl-chinolin-palladiumchlorid-komplexes

Chloro[N-3′5′-η-(4′-methylpentenyl)quinoline-2]palladium was synthesized; the NMR-spectrum of this compound is helpful in distinguishing the cis/trans-isomers of other non-bridged π-allyl-base-palladium chloride complexes.     

Synthesis,X-ray structure and spectroscopy of Cu(II) complexes derived from diacetylazine dioxime

Complexes of Cu(II) with the polydentate diacetylazine dioxime ligand C₈H₁₄N₄O₂ have been synthesized by template and non-template reactions. The crystal structure of [Cu(C₈H₁₃N₄O₂)]₂[ClO₄]₂(C₂H₅OH)₂ has been determined to establish the conformation of the ligand and the coordination of the oxime function. The structural analysis shows that the nearly planar [C₈H₁₃N₄O₂]^? group behaves as a bridging tetradentate ligand. The distorted square-pyramidal coordination about each Cu atom includes three N donors from two oxime and azine and one O donor from the other oxime, the ethanol molecule occupying the apical position. A perchlorate anion is loosely bonded to Cu. The intramolecular Cu…Cu separation is 3.725(2) Å. The compound crystallizes in the centrosymmetric space group P$\text{1}$ triclinic lattice with refined lattice parameters of a = 11.963(8) Å, b = 9.784(7) Å, c = 7.501(6) Å, α = 90.69(4)°, β = 104.53(4)°, γ = 90.83(4)°, V = 849.7 ų and Z = 2. Full-matrix least-squares refinement of 1490 independent reflexions led to final discrepancy indices, R = 0.059, and R_w = 0.065. The Cu centres are highly coupled as indicated by the ESR spectrum. There is no evidence that the C₈H₁₄N₄O₂ ligand stabilizes unusual oxidation states of Cu.     

Intermolecular interactions of punicin derivatives

The 2- and 4-methyl derivates of punicin [N-(2′,5′-dihydroxyphenyl)-pyridinium chloride] were subjected to Knoevenagel reactions. Starting materials as well as reaction products were examined with respect to homo and hetero-intermolecular interactions. It was found that N-(2′,5′-dihydroxyphenyl)-2-methylpyridinium chloride forms a stable 2:1 complex to hydroquinone. Decomplexation can be accomplished by anion exchange to tetraphenylborate, or by competing complexation with p-benzoquinone. Results of three single crystal X-ray analyses as well as NMR titrations and dilution experiments are presented.     

Preparation of new poly(ether-amide-imide)s from 1,4-bis-[4-(trimellitimido)phenoxy]butane and aromatic diamines via direct polyamidation

Several new Poly(ether-amide-imide)s were prepared by direct polycondensation reactions of 1,4-bis-[4-(trimellitimido)phenoxy]butane with various aromatic diamine. Two direct polycondensation techniques were used: direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone/triphenyl phosphite/calcium chloride/pyridine and direct polycondensation in a tosyl chloride/pyridine/N,N-dimethylformamide system. All the monomers and polymers were fully characterized by means of FTIR, ¹H-NMR spectroscopy and elemental analyses and properties of the polymers including solution viscosity, thermal behavior and solubility were studied.     

Syntheses of N-silylformamidines by the hydrosilylation of carbodiimides

The hydrosilylation of carbodiimides was found to proceed at higher temperatures in the presence of catalytic amounts of palladium chloride or tris-(triphenylphosphine)chlororhodium to afford N-silylformamidines in high yield. These were found to be good precursors to formamidines and N-acetyl-formamidines.     

Pre-activation based, highly alpha-selective O-sialylation with N-acetyl-5-N,4-O-carbonyl-protected p-tolyl thiosialoside donor

A new method for pre-activation of N-acetyl-5-N,4-O-carbonyl-protected p-tolyl thiosialoside donor with AgOTf and p-toluenesulfenyl chloride followed by coupling with other p-tolyl thioglycosides is reported. Excellent α-sialylation yields were achieved for these coupling reactions, as high as 91% yield of only α-isomer.     

Effect of solvent nature on free-radical copolymerization of N,N-diallyl-N,N-dimethylammonium chloride and maleic acid

The free-radical copolymerization of N,N-diallyl-N,N-dimethylammonium chloride with maleic acid in DMSO proceeds to yield statistical copolymers. When the reaction is carried out in methanol, the copolymers of constant compositions (N,N-diallyl-N,N-dimethylammonium chloride: maleic acid = 2: 1) are formed over a wide range of comonomer ratios in the starting mixture. The formation of alternating copolymers in this case may be attributed to formation of donor-acceptor complexes between the comonomers in the methanol solution, as evidenced by UV spectrophotometry. The kinetic features of the process have been investigated, and the relative activities of the monomers have been assessed. ¹³C NMR studies have demonstrated that, regardless of the solvent nature, both double bonds of N,N-diallyl-N,N-dimethylammonium chloride are involved in copolymerization via intermolecular cyclization accompanied by formation of pyrrolidinium structures.     

Efficient preparation of (Z)-alkenyl derivatives from (Z)-vinyl (N,N-diisopropyl)carbamate via Ni-catalysed coupling reactions

A (Z)-vinyl (N,N-diisopropyl)carbamate treated with Grignard reagents, under Wenkert Nickel-catalysed conditions, gave access to several substituted (Z)-alkenyl derivatives. These Nickel-catalysed reactions, carried out with vinyl-, phenyl-, p-methoxyphenyl-, trimethylsilylmethylmagnesium bromide and benzylmagnesium chloride, led to the corresponding (Z)-alkenyl derivatives in good yields and high stereoselectivities.     

Copolymerization of N,N-diallyl-N,N-dimethylammonium chloride and vinyl acetate

The free-radical copolymerization of N,N-diallyl-N,N-dimethylammonium chloride with vinyl acetate in DMSO, methanol, and a methanol-water (70: 30, mol %) mixture proceeds to yield statistical copolymers. The nature of solvents significantly affects the reactivity ratios of the comonomers. N,N-Diallyl-N,N-dimethylammonium chloride shows a higher reactivity than vinyl acetate. The kinetic features of the processes have been investigated, and the structure and properties of the copolymers have been studied.     

A new way of synthesizing heterocyclic primary sulfonamide probes for carbonic anhydrase

An N,N-bis(p-methoxybenzyl)-protected α-acetyl-α-diazo-methane sulfonamide proved to be a useful building block for accessing new 5-methyl-1,2,3-thiadiazole-4-sulfonamide as well as methyl 3-sulfamoyl-1H-pyrazole-5-carboxylate. The latter was further subjected to N-alkylation and N-arylation reactions. All resulting compounds showed potent inhibition of I, II and particularly of cancer-related IX and XII isoforms of human carbonic anhydrase.     

Organometallic oxime and allied derivatives II. Synthesis and properties of some tri-n-butylgermanium oximates

Tributylgermanium oximates have been prepared by reactions (a) of tributylgermanium chloride with (i) oximes in the presence of a base, (ii) sodium oximates, and (iii) organotin oximates, as well as (b) of tributylgermanium ethoxide and oxide with oximes.The derivatives have been characterised by elemental analyses, molecular weight measurements and IR spectra. Their reactions have been studied in detail.