IR Spectra of N,N′-Ethylene-Bis(salicylaldiminates) and N,N′-ethylene-Bis(acetylacetoniminates) of Ni(II), Cu(II), and Zn(II)

Vibrational spectra of N,N′-ethylene-Bis(salicylaldiminaates) and N,N′-ethylene-Bis(acetylacetoniminates) of nickel (II), copper (II), and zinc (II) are studied experimentally (IR spectroscopy, 400–4000 cm⁻¹) and theoretically (B3LYP), band assignment is given, and the distribution of potential energy of normal vibrations in internal coordinates is studied. Differences between vibrational spectra of the complexes are discussed. Thermodynamic functions of gas-phase complexes corresponding to temperatures of 298 and 800 K are calculated.     

Simultaneous separation and determination of Cu(II), Fe(III), and Pb(II) by reversed-phase ion-pair chromatography withN,N,N′, N′-ethylene-diaminetetrakis(methylenephosphonic Acid)

Summary A reversed-phase ion-pair chromatographic (RPIPC) method withN,N,N′, N′-ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP) as coordinating agent has been developed for simultaneous separation and detection of Cu(II), Fe(III), and Pb(II) ions. Response is linearly dependent on amount of sample over the range 9.52–50.8 μg mL⁻¹ for Cu(II), 8.31–41.8 μg mL⁻¹ for Fe(III), and 37.3–51.8 μg mL⁻¹ for Pb(II). The method has been applied successfully to an artificial mixed-ore sample.     

Investigation on the thermal decomposition some heterodinuclear NiII-MII complexes prepared from ONNO type reduced Schiff base compounds ( M II=ZnII, CdII)

N,N′-bis(salicylidene)-1,3-propanediamine (LH₂), N,N′-bis(salicylidene)-2,2′-dimethyl-1,3-propanediamine (LDMH₂), N,N′-bis(salicylidene)-2-hydroxy-1,3-propanediamine (LOH₃), N,N′-bis(2-hydroxyacetophenylidene)-1,3-propanediamine (LACH₂) and N,N′-bis(2-hydroxyacetophenone)-2,2′-dimethyl-1,3-propanediamine (LACDMH₂) were synthesized and reduced to their phenol-amine form in alcoholic media using NaBH₄ (L^HH₂, LDM^HH₂, LOH^HH₂, LAC^HH₂ and LACDM^HH₂). Heterodinuclear complexes were synthesized using Ni(II), Zn(II) and Cd(II) salts, according to the template method in DMF media. The complex structures were analyzed using elemental analysis, IR spectroscopy, and thermogravimetry. Suitable crystals of only one complex were obtained and its structure determined using X-ray diffraction, NiLAC^H·CdBr₂·DMF₂, space group orthorhombic, Pbca, a=20.249, b=14.881, c=20.565 ? and Z=8. The heterodinuclear complexes were seen to be of [Ni·ligand·MX₂·DMF₂] structure (ligand=L^H2−, LDM^H2−, LOH^H2−, LAC^H2−, LACDM^H2−, M=Zn^II, Cd^II, X=Br⁻, I⁻). Thermogravimetric analysis showed irreversible bond breakage of the coordinatively bonded DMF molecules followed by decomposition at this temperature.     

Investigation of azomethine group vibrations in aromatic schiff bases and their N-oxides by vibrational spectroscopy methods

The effects of fluorine substitution in benzene rings and quaternization of the nitrogen atom in Schiff bases of the general formula R−CH=N−R′ on the vibration characteristics of the azomethine group are analyzed. Normal vibrations and intensities of IR bands are calculated. It is shown that the spectroscopic behavior of the C=N bond is almost independent of the electronic effects of substituents in the benzene rings of the molecules studied, and the changes in the intensities of ν_C=N bands are caused by interactions between vibrations. This points to the stability of this bond in the series of molecules under consideration. For diphenylnitrones, N→O vibrations are identified. L. M. Litvinenko Institute of Physical Organic Chemistry and Carbon Chemistry. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 2, pp. 310–315, March–April, 1995. Translated by L. Smolina     

Synthesis and Complexation of a New vic -Dioxime Ligand

 A new vic-dioxime ligand, N,N′-bis-(8-salicylideneimino-1-naphthyl)-diaminoglyoxime, has been synthesized from anti-dichloroglyoxime and 1-amino-8-salicylideneiminonaphthalene which has been prepared via the condensation product of 1,8-diaminonaphthalene and salicylaldehyde. The vic-dioxime ligand forms trinuclear complexes with Cu(II), Ni(II), Co(II), and Pd(II). The uranyl complex of this ligand has a 2:1 metal-ligand ratio and a binuclear structure with μ-hydroxo bridges.     

Synthesis, Characterization and Relaxation Properties of Four Non-ion Transition Metal Manganese(II), Cobalt(II), Nickel(II) and Copper (II) Complexes with Derivatives from Diethylene Triamine Pentaacetic Acid and Isoniazid

A novel ligand (H₂L), diethylenetriamine-N,N′,N′′-triacetylisoniazide N,N′′-bisacetic acid, and its four non-ion transition metal complexes, ML · nH₂O (M = Mn, n = 4; M = Co, Ni, n = 2; M = Cu, n = 1), have been synthesized and characterized on the basis of elemental analysis, molar conductivity, ¹H-NMR, FAB-MS, TG-DTA analysis and IR spectrum. In addition, relaxivity (R₁) of the complexes was determined, the relaxivity of MnL, CoL, NiL, CuL as well as Gd(DTPA)²⁻ used as a control are 6.94, 2.79, 2.52, 1.59 and 4.34 l mmol⁻¹ s⁻¹, respectively. The relaxivity of MnL is larger than that of Gd(DTPA)²⁻. The results show that the complex of MnL may be a potential MRI contrast agent.     

Kinetics and Mechanism of the Reactions of Picolinic Acid with Dichloro-{1-alkyl-2-(arylazo)imidazole}palladium(II) Complexes

The reaction between Pd(N,N′)Cl₂ [N,N′ ≡ 1-alkyl-2-(arylazo)imidazole (N,N′) and picolinic acid (picH) have been studied spectrophotometrically at λ = 463 nm in MeCN at 298 K. The product is [Pd(pic)₂] which has been verified by the synthesis of the pure compound from Na₂[PdCl₄] and picH. The kinetics of the nucleophilic substitution reaction have been studied under pseudo-first-order conditions. The reaction proceeds in a two-step-consecutive manner (A → B → C); each step follows first order kinetics with respect to each complex and picH where the rate equations are: Rate 1 = {k′₀ + k′₂[picH]₀} × [Pd(N,N′)Cl₂] and Rate 2 = {k′′₀ + k′′₂[picH]₀}[Pd(N,O)(monodentate N,N′)Cl₂] such that the first step second order rate constant (k′₂) is greater than the second step second order rate constant (k′′₂). External addition of Cl⁻ (as LiCl) suppresses the rate. Increase in π-acidity of the N,N′ ligand, increases the rate. The reaction has been studied at different temperatures and the activation parameters (Δ^‡H° and Δ^‡S°) were calculated from the Eyring plot.     

Reaction of trifluoromethanesulfonamide with alkenes and cycloocta-1,5-diene under oxidative conditions. Direct assembly of 9-heterobicyclo[4.2.1]nonanes

Reactions of trifluoromethanesulfonamide with α-methylstyrene, 2-methylpent-1-ene, and cycloocta-1,5-diene in the system t-BuOCl-NaI were studied. In the reaction with α-methylstyrene 1-iodo-2-phenylpropan-2-ol was the only isolated product. The reaction with 2-methylpent-1-ene gave a mixture of N,N′-(2-methylpentane-1,2-diyl)bis(trifluoromethanesulfonamide), trifluoro-N-(2-hydroxy-2-methylpentyl)-methanesulfonamide, and N,N′-[oxybis(2-methylpentan-2,1-diyl)]bis(trifluoromethanesulfonamide). Trifluoromethanesulfonamide reacted with cycloocta-1,5-diene to produce a mixture of 2,5-diiodo-9-(trifluoromethylsulfonyl)-9-azabicyclo[4.2.1]nonane and 2,5-diiodo-9-oxabicyclo[4.2.1]nonane; this reaction may be regarded as the first example of direct assembly of bicyclononane skeleton.     

Segregation of human prostate tissues classified high-risk (UK) versus low-risk (India) for adenocarcinoma using Fourier-transform infrared or Raman microspectroscopy coupled with discriminant analysis

Vibrational spectroscopy techniques can be applied to identify a susceptibility-to-adenocarcinoma biochemical signature. A sevenfold difference in incidence of prostate adenocarcinoma (CaP) remains apparent amongst populations of low- (e.g. India) compared with high-risk (e.g. UK) regions, with migrant studies implicating environmental and/or lifestyle/dietary causative factors. This study set out to determine the biospectroscopy-derived spectral differences between risk-associated cohorts to CaP. Benign prostate tissues were obtained using transurethral resection from high-risk (n = 11, UK) and low-risk (n = 14, India) cohorts. Samples were analysed using attenuated total reflection Fourier-transform infrared (FTIR) spectroscopy, FTIR microspectroscopy and Raman microspectroscopy. Spectra were subsequently processed within the biochemical cell region (1,800⁻¹–500 cm^–1) employing principal component analysis (PCA) and linear discriminant analysis (LDA) to determine whether wavenumber–absorbance/intensity relationships might reveal biochemical differences associated with region-specific susceptibility to CaP. PCA-LDA scores and corresponding cluster vector plots identified pivotal segregating biomarkers as 1,582 cm⁻¹ (Amide I/II trough); 1,551 cm⁻¹ (Amide II); 1,667 cm⁻¹ (Amide I); 1,080 cm⁻¹ (DNA/RNA); 1,541 cm⁻¹ (Amide II); 1,468 cm⁻¹ (protein); 1,232 cm⁻¹ (DNA); 1,003 cm⁻¹ (phenylalanine); 1,632 cm⁻¹ [right-hand side (RHS) Amide I] for glandular epithelium (P < 0.0001) and 1,663 cm⁻¹ (Amide I); 1,624 cm⁻¹ (RHS Amide I); 1,126 cm⁻¹ (RNA); 1,761, 1,782, 1,497 cm⁻¹ (RHS Amide II); 1,003 cm⁻¹ (phenylalanine); and 1,624 cm⁻¹ (RHS Amide I) for adjacent stroma (P < 0.0001). Primarily protein secondary structure variations were biomolecular markers responsible for cohort segregation with DNA alterations exclusively located in the glandular epithelial layers. These biochemical differences may lend vital insights into the aetiology of CaP.     

Copper(II) complexes of 2-carbamoylethyl derivatives of linear diamines. Crystallographic evidence for amido oxygen binding prior to deprotonation of amide nitrogens

There has been considerable interest in the coordination chemistry of linear and macrocyclic amides⁽¹⁾. Deprotonation of the amide nitrogen is known to occur with various metal ions and the sites of coordination are generally considered to be the carbonyl oxygen prior to deprotonation and the amide nitrogen after deprotonation. However, oxygen binding has generally been inferred from indirect evidence^(2,3). We now report the results of some studies on the interaction of copper(II) with a series of 2-carbamoylethyl derivatives of linear diamines, namelyN,N′-bis(2-carbamoylethyl)ethylenediamine (1),N,N,N′,N′-tetrakis(2-carbamoylethyl)ethylenediamine (2)N,N′-bis(2-carbamoylethyl)trimethylenediamine (3) andN,N,N′,N′-tetrakis(2-carbamoylethyl)trimethylenediamine (4) which confirm carbonyl oxygen binding prior to amide deprotonation.     

Sulfenylation reactions activated by thionyl and sulfuryl chlorides

Reactions ofN-(4-nitrophenylthio)morpholine,N,N′-thiobismorpholine, andN,N′-dithiobismorpholine with thionyl chloride or sulfuryl chloride at −40°C afford electrophilic chlorosulfenylating reagents, which add to the C=C bond of norbornene in high yields. Semiempirical quantum-chemical calculations and comparison of the relative reactivity of the sulfenylating complexes formed upon activation of arenesulfenamides by sulfur and phosphorus oxohalides were performed. The mechanism of the reactions is discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2516–2518, December, 1998.     

Synthesis and Complexation of a Novel Soluble vic -Dioxime Ligand

Summary.  A new soluble vic-dioxime 1,4-(isobutyl)-2,3-bis-(hydroxyimino)-5,6-phenylpiperazine was prepared as a mixture of isomers from anti-dichloroglyoxime and N,N′-bis-(isobutyl)-stilbendiamine which reacts to N,N′-coordinated planar metal complexes with Ni(II), Cu(II), Co(II), and Pd(II). Oxidation of the Co(II) complex in the presence of pyridine leads to an octahedral complex containing pyridine and chloride as axial ligands in addition to the vic-dioxime ligands. The uranyl complex has a 1:1 metal:ligand ratio and a dinuclear structure with μ-hydroxo bridges. Received November 14, 2000. Accepted (revised) January 23, 2001     

Multinuclear NMR investigation on organometallic gold(III) pentafluorophenylarylazoimidazole complexes

Reaction of [Au(C₆F₅)(tht)₂Cl](OTf) with RaaiR′ in CH₂Cl₂ medium leads to [Au(C₆F₅)(RaaiR′)Cl](OTf) [RaaiR′ = p-R–C₆H₄–N=N–C₃H₂–NN-1-R′, (1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH₂CH₃ (2), CH₂Ph (3), tht is tetrahydrothiophen]. The maximum molecular peak of [Au(C₆F₅)(MeaaiMe)Cl] is observed at m/z 599.51 (100 %) in the FAB mass spectrum. Ir spectra of the complexes show –C=N– and –N=N– stretching near at 1590 and 1370 cm⁻¹ and near at 1510, 955, 800 cm⁻¹ due to the presence of pentafluorophenyl ring. The ¹H-NMR spectral measurements suggest methylene, –CH₂–, in RaaiEt gives a complex AB type multiplet while in RaaiCH₂Ph shows AB type quartets. ¹³C-NMR spectrum of complexes confirm the molecular skeleton. In the ¹H-¹H-COSY spectrum as well as contour peaks in the ¹H-¹³C HMQC spectrum for the present complexes, assign the solution structure and stereoretentive conformation. The electrochemistry gives the ligand reduction peaks.     

Oxidation of α-methylstyrene on an MCM-22 encapsulated (<Emphasis Type="Italic">R,R</Emphasis>)-(−)-<Emphasis Type="Italic">N,N′</Emphasis>-bis(3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butylsalicylidene)-1,2-cyclohexanediaminocobalt(II) catalyst

(R, R)-(−)-N, N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminocobalt(II) was encapsulated into MCM-22 using the zeolite synthesis method. The encapsulated catalyst proved to be active in the oxidation of α-methylstyrene with NaOCl with higher specific activity than the homogeneous catalyst. At the same time, this encapsulated catalyst was completely inactive in the hydrolytic kinetic resolution of racemic styrene oxide. This observation is in a good correlation with the assumption of the cooperative bimetallic mechanism proposed by Annis and Jacobsen.     

Alkylation of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with alkyl halides and dimethyl sulfate

Salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides, RCH(OH)CH₂N(O)=NO⁻ M⁺ (R=Me, Prⁱ, or Bu^t; and M=Li, Na, K, Ag, NH₄, or Me₄N), were prepared. Their alkylation with alkyl halides R′X (X=Cl, Br, or I) and dimethyl sulfate was studied. Generally, alkylation afforded mixtures ofN-(β-hydroxyalkyl)-N′-alkoxydiazeneN-oxides RCH(OH)CH₂N(O)=NOR′ andO-alkyl-N-(β-hydroxyalkyl)-N-nitrosohydroxylamines RCH(OH)CH₂N(NO)OR′. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1996–2001, October, 1998.     

Hydrogen-bonded supramolecular motifs in crystal structures of trimethoprim barbiturate monohydrate (I) and 2-amino-4,6-dimethylpyrimidinium barbiturate trihydrate (II)

In the present study, we report the crystal structures of two organic salts, namely 2,4-diamino-5-(3′,4′,5′-trimethoxybenzyl)pyrimidinium (TMP) barbiturate monohydrate (TMPBAR) (I), 2-amino-4,6-dimethylpyrimidinium (AMPY) barbiturate trihydrate (AMPYBAR) (II). In both complexes, one ring nitrogen of TMP and AMPY are protonated as a result of proton transfer from the−CH₂ group of barbituric acid. In compound (I), the TMP cation and barbiturate anion are paired through twoN−H···O and one N−H···N hydrogen bonds. This pair further self-organizes through N−H···O hydrogen bonds to generate an array of six hydrogen bonds. These arrays are further cross-linked by N−H···O hydrogen bonds forming a sheet-like structure. The water molecule is also embedded in the sheet via O−H···O and C−H···O hydrogen bonds, forming a rosette-like supramolecular motif. TMP cations are also bridged by alternating water molecules via C−H···O and O−H···N hydrogen bonds. In compound (II), the symmetrical barbiturate anions self-organize on both sides through N−H···O hydrogen bonds generating a supramolecular chain. These chains are cross-linked by the three water molecules. A pair of barbiturate anions and two water molecules constitute an array of four hydrogen bonds (DADA quadruple array). These arrays are cross-linked by another water molecule. 2-Amino-4,6-dimethylpyrimidine cations are paired through N−H···N hydrogen bonds. These pairs are bridged by three water molecules generating a supramolecular ribbon. The barbiturate chains and base pairs are arranged in an alternate manner via N−H···O and O−H···O hydrogen bonds to generate a 3-D network.     

Solvent directed templated synthesis of mono- and di(Schiff base) complexes of Ni(II)

The mono- and binuclear complexes Ni(Salen) (I) and Ni₂(Salen)₂ (II) (H₂Salen = N,N′-bis(salicylidene)ethane-1,2-diamine), have been synthesized and structurally characterized by single-crystal X-ray diffraction studies. The X-ray structural analyses show that the metal center of complex I is mononuclear and tetracoordinate with a distorted tetrahedron, whereas the metal-centered complex II is binuclear and pentacoordinate with rectangular pyramid geometries, respectively. The electrochemical studies evidenced for the mononuclear Ni(II) complex shows one quasireversible reduction potential at −0.80 V (E _pc ) and the binuclear Ni(II) complex shows a reduction potential at −0.90 V (E _pc ) in the cathodic region. The article is published in the original.