Heteroorganic betaines

Photolysis and thermal decomposition of betaines R₃P−CR¹R²−SiR³R⁴−S⁻ (1) follows two main pathways: (a) a Corey—Chaykovsky type reaction with elimination of Ph₃P and generation of silathiirane (2) and (b) a retro-Wittig type reaction accompanied by elimination of R₃P=CR¹R² and generation of silanethione R³R⁴Si=S (3). Highly reactive compounds2 and3 undergo subsequent transformations to give derivatives of tetrahydro-1,4-dithia-2,5-disilin, 1,3-dithia-2,4-disilolane, and phosphonium salts ofsymm-tetraorganodisilthiane dithiolates [Ph₃P⁺CHR¹R²]₂[(R³R⁴SiS⁻)₂S]. The structures of the compounds obtained were established by X-ray diffraction analysis and multinuclear NMR spectroscopy. For part 3, see Ref. 1. The betaines Et₃P⁺CHMeSiMe₂S⁻ and Et₃P⁺CHMeSiPh₂S⁻ with alkyl groups at the phosphorus atom are distinguished by high thermal stability; their spectral characteristics do not change during storage of solutions of these compounds in pyridine-d₅ or metastable solutions in benzene-d₆ for 1–2 years at −20°C in sealed evacuated tubes or on heating (150°C) for 15 h. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1594–1603, September, 2000.     

Reaction of Ru3(CO)12 with 1,3-diferrocenylprop-2-ene-1-one. Crystal and molecular structures of the complexes Ru3(CO)8(FcC=CHCOFc)2 and [Ru(CO)2Cl(FcC=CHCOFc)]2

The reaction of Ru₃(CO)₁₂ with 1,3-diferrocenylprop-2-en-1-one,trans-FcCH=CHCOFc (where Fc is ferrocenyl), in boiling hexane afforded the complex (2c), which was converted into (3c) upon further heating. These complexes gave the complex (4) containing two Cl-bridged oxaruthenacycles upon dissolution in CHCl₃ or CH₂Cl₂. The structures of complexes 3 and 4 were established by X-ray diffraction analysis. According to the data of¹H NMR spectroscopy, the Cl-bridged complex exists in solutions as a mixture of isomers along with the monomeric form resulting from the cleavage of the halide bridges. All interconversions of the isomers occur with the participation of the monomeric form. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1616–1623, September, 2000.     

UV photolysis of protonated ruthenium and osmium decamethylmetallocenes as a new method for synthesis of the metallonium cations

Decamethylmetallocenes Cp^* ₂M (M=Ru, Os) in the presence, of acids (CF₃CO₂H, CF₃SO₃H) give thepprotonation products [Cp^* ₂MH]⁺An⁻. Broad-band UV photolysis of their solutions results in the formation of the salts of onium cations . A preparative procedure for the synthesis of these salts has been developed. Hydrolysis of the salts gives the carbinol Cp^*MC₅Me₄CH₂OH. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 587–591. March, 1999.     

Ab initio study of the complexes of first-row transition-metal ions with CH, CH2, and CH3

The geometries and bonding characteristics of the complexes of the first-row transition-metal ions with CH, CH₂ and CH₃ were investigated byab initio molecular orbital theory. MCH⁺ and MCH₂ ⁺ are linear and coplanar, respectively. Both of them are with obvious treble or double bond characteristics, but these multiple bonds are mostly “imperfect”. The calculated bond dissociation energies of , and are mostly close to the experimental values, and appear in similar periodic trends from Sc to Zn. Project supported by the National Natural Science Foundation of China (Grant No. 29170070).     

Synthesis,structures and properties ofN-(trihalogermylmethyl)-substituted amides,lactams and imides,the derivatives of the five-coordinate germanium

The formation of trichlorogermyl-substituted amides, lactams, and imides occurs when 2Et₂O·HGeCl₃ is condensed with compounds possessing the -NCH₂Cl fragment and equally well when HGeCl₃ interacts with compounds containing -NCH₂OH and-NCH₂OSiMe₃ groups. In some cases, the use of the latter is more advantageous from the preparative point of view. In compounds thus obtained, the germanium is five-coordinate due to the coordination . Deceased August 13, 1993. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1793–1799, October, 1993.     

FeCl3 solutions in isopropanol-water

Summary This paper is devoted to the characterization of FeCl₃ solutions in isopropanol containing water. For this goal optical absorption and e.p.r. techniques have been used in conjunction with magnetization and M?ssbauer data reported very recently. It is shown that in a 10⁻² M solution of FeCl₃ containing 0.4 M of water the main iron(III) species present in the solution are [FeCl₄]⁻ (55%) and [FeCl₂(H₂O)₄]⁺ (20%) while the remainding 25% is due to dihydroxo dimers, . When the water concentration increases the [FeCl₄]⁻ anions are progressively destroyed, the main iron(III) species present in the solution being the dihydroxodimers and [FeCl₂(H₂O)₄]⁺. The variation of the concentration of the three species mentioned with the water content and FeCl₃ concentration is presented in this paper.     

Ab initio study of the structure,force field,and vibrational spectrum of the LiClO3 molecule

The geometrical structure and the vibrational spectrum of the LiClO₃ molecule are studied by the Hartree-Fock-Roothaan (HF) and configurational interaction (CI) methods taking into account single and double excitations and Davidson's correction for quadruple excitations. Double-zeta basis sets of Huzinaga-Dunning and McLean-Chandler complemented with polarization and diffuse functions are used. Potential surface sections corresponding to migration of the Li⁺ cation around the ClO ₃ ⁻ fragment are investigated. It was found that the LiClO₃ molecule has a single stable configuration of C_s symmetry with the bidentate coordination of the Li⁺ cation by the ClO ₃ ⁻ anion. The cyclic fragment is nonplanar (the dihedral angle θ(LiO₂Cl)=173°). The tridentate configuration of C_3v symmetry lies higher than the equilibrium configuration by 24.5 (HF) or 18.3 (CI) kJ/mole and is not an isomer. The ab initio force field of the molecule was refined by the scaling method. Some assignments of the IR bands of the matrix-isolated molecular forms existing in vapor over lithium chlorate are corrected. The vibration frequencies (cm⁻¹) and IR intensities (km/mole; in parentheses) are calculated with the refined force field: A′ type 1099(236), 856(81), 630(73), 557(119), 481(87), 156(66); A″ type 887(229), 459(35), 367(23). Ivanovo State Chemical Technological Academy. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 3, pp. 440–449, May–June, 1996.     

Potentiometric study of the formation of hydroxo complexes of [Cu(terpy)]2+. Synthesis and crystal structure of [Cu(terpy) (H2O)](CF3SO3)2

Two complexes of formula [Cu(terpy)(H₂O)](CF₃SO₃)₂ (1) and [Cu(terpy)(OH)]BPh₄ (2) (terpy=2,2′∶6′,2″-terpyridine and BPh₄=tetraphenylborate anion) have been synthesized and characterized by spectroscopic techniques. The x-ray crystal structure of (1) has been determined by x-ray diffraction. The structure is made up of [Cu(terpy)(H₂O)]²⁺ mononuclear cations plus semi-coordinated CF₃SO₃ ⁻ anions. The coordination geometry around the copper atom is approximately elongated tetragonal octahedral. The oxygen atom of water and the three nitrogen atoms of terpy occupy the equatorial sites whereas the apical ones are filled by trifluoromethanesulphonate oxygen atoms. The formation of hydroxo complexes of [Cu(terpy)(H₂O)]²⁺ has been investigated by potentiometry in aqueous solutions and the constants of the Equilibria (1) and (2)      

A new type of polarographic catalytic wave of organic compound

The polamgraphic behavior and catalytic wave mechanism of medroprogestemne acetate (MPA) were studied in both aqueous and DMF media. In 0.2 mol/L acetic acid-sodium acetate (pH 5.0) buffer solution, the bond of MPA first undergoes le, lH⁺ reduction to form protonated free radical HMPA, the further reduction of HMPA in le,1H⁺ process is simultaneous with the dimerization reaction between HMPA and neutral molecular MPA. In DMF media containing 0.1 mol/L tetrabutylammonium tetrafluoborate (TBA.BF₄), the bond of MPA shows two le, 1H⁺reduction waves, which are ascribed to the reduction of MPA and free radical MPA.^-, respectively. Here, no dimerization reaction occurs. These processes produce the reduction wave of MPA. In the presence of oxidant KIO₃,a polamgraphic catalytic wave of MPA is observable due to a chemical reaction between HMPA. or MPA.^- and KIO₃ as well as its intermediate species to regenerate MPA. The catalytic wave, which is caused by the reduction of organic compound itself and the chemical reaction between oxidant and organic intermediate free radical to regenerate original organic compound, is a new-type wave of organic compound. Under optimum experimental conditions, the sensitivity of MPA catalytic wave in the presence of KIO₃ is an order of magnitude higher than that of its reduction wave. The catalytic wave can be used for analytical purpose. The calculated rate constant of catalytic reaction is 1.7 × 10³ mol·L^-1·s^-1. Project supported by the National Natural Science Foundation of China (Grant No. 29875017).     

Mechanism of the long wavelength photolysis of CS2 vapor

It is proposed that in the long wavelength (λ ≥ 290 nm) photolysis of CS₂ vapor the observed CS and S₂ are produced in the reaction sequence:      

Heteroorganic betaines

The structures of three silicon-containing organophosphorus betaines containing the⁺P−C−Si−S⁻ fragment were established by X-ray diffraction study. Due to the attractive electrostatic interaction between the anionic and cationic centers, the main chain adopts agauche conformation, whereas this chain in theS-ethyl derivative of the phosphonic salt [Ph₃P⁺−CMe₂−SiMe₂SEt]Br⁻ adopts atrans conformation. The changes in the geometric parameters of betaines depending on the substituents at the phosphorus, carbon, and silicon atoms were analyzed. The P−S bond can in principle be formed, resulting in the closure of the four-membered ring provided that additional steric hindrances at the silicon atom occur.     

Synthesis of New Hybrid Organic-Inorganic Alumina Gels by the Sol-Gel Method

New hybrid organic-inorganic alumina gels have been prepared by reacting aluminum sec-butoxide and propane-1,2-diol, in CCl₄ as solvent. This reaction occurred without water addition and without the use of any catalyst, leading to the formation of transparent and monolithic gels. IR,²⁷Al and¹³CNMR show that an interchange reaction between OBu ^s alkoxide groups and diol groups occurred, leading to the hybrid gels. Samples heat treated at different temperatures under argon are weakly porous and have a small specific surface area. XRD indicates the presence of pure α-alumina at 1450°C.     

Relations entre structure chimique et grandeurs de retention. VII. Composés de structure cyclopropanique

Résumé Les auteurs ont étudié le comportement chromatographique sur plusieurs phases stationnaires polaires et non polaires de composés cyclopropaniques stéréoisomêres: où R=H ou CH₃ et X=CH, COOCH₃ ou CH₂OH. Les résultats sont interprétés en fonction de la configuration de X par rapport à , de la nature électronique de X et de l'orientation du phényle par rapport au plan du cyclopropane.

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Relationship between chemical structure and retention. VII. Cyclopropane compounds

Summary The chromatographic behaviour, on several polar and non polar phases, of stereoisomeric cyclopropanes has been studied R=H or CH₃ and X=CN, COOCH₃, CH₂OH. The results are interpreted in terms of the X versus configuration, the electronic nature of X and the orientation of the phenyl ring in relation to plane of the cyclopropane ring.

     

Preparation and crystal structure of bis[(dibenzo-18-crown-6)potassium]bis(μ<Subscript>2</Subscript>-chloro)-tetrachlorodicuprate(II)

A new complex compound bis[(dibenzo-18-crown-6)potassium]bis(μ₂-chloro)-tetrachlorodicuprate( II), {[K(Db18c6)]₂Cu₂Cl₆} (I) was prepared and its crystal structure was investigated by XRD analysis. Complex molecule I consist of anion [Cu₂Cl₆]²⁻ located in a crystallographic center of inversion, and two centrosymmetrical to each other complex cations [K(Db18c6)]⁺ of “guest-host” type: the cation K⁺ is located in the cavity of the crown-ligand Db18c6 and is coordinated by all its six O atoms, and also by one Cl atom of anion [Cu₂Cl₆]²⁻. The coordination of this cation K⁺ is enlarged up to hexagonal-bipyramidal due to the formation of unusual coordination bond K⁺ → π(      

Paramagnetic centers by X-ray-irradiation of aluminium hydroxide

EPR spectra of paramagnetic centers originating from X-ray-irradiation of aluminium hydroxide at room temperature have been measured. The EPR spectrum represents a superposition of EPR spectra of ionic centers O^–, holes of type and trapped electrons. Radiation chemical yield of paramagnetic centers observed at room temperature (293 K) is G(spins.)=4.4±0.6) spins per 100 eV absorbed energy. The decay of paramagnetic centers in irradiated Al(OH)₃ was oberved at 293 K. The rate constant of the paramagnetic centers decay in irradiated Al(OH)₃ is K₂=(0.0980±0.0019) kg·mol^–1·min^–1 and their half-life is 9.43±0.18 days.Dedicated to the memory of the late Genrikh Markovis Kolyiari.     

Synthesis of [D-phe3 (NH2); Pro3; D-Ala6]- and [D-Phe2 (NO2); Pro3; D-Ala6]luliberins

In order to study the influence of substituents of the aromatic ring of D-phenyl-alanine on the inhibiting capacity of luliberian analogs, we have synthesized two new analogs: and luliberin. The synthesis was performed by the fragmentary condensation method using 2+(3+5) and 2+(5+3) schemes. A new and convenient method of obtaining the amide of the C-terminal tetrapeptide of the luliberin sequence has been developed. In the condensation of the fragments, both the azide and the carbodimide method of synthesis with the addition of l-hydroxybenzotriazole were used. The guanidino group of arginine was protected by nitration, while the hydroxy groups of serine and of tyrosine were not protected. The complete elimination of the protective groups from the decapeptides was performed by catalytic hydrogenation over Pd on carbon and by anhydrous HF with the addition of anisole at 0°C. The protected octa- and decapeptides were purified by gel filtration on Sephadex LH-20 in ethanol or by preparative thin-layer chromatography on silica gel plates. The final peptides were purified by ion-ex-exchange chromatography on Sephadex CM-25. A. A. Zhdanov Leningrad State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 706–714, September–October, 1980.     

IR spectroscopic investigation of the structure of polymeric uranyl di(2-ethylhexyl)phosphate molecules in C6H6 and CCl4 solutions

Using IR spectroscopy, we studied the types of coordination of POO groups in di(2-ethylthexyl)phosphate anionx X⁻ with UO ₂ ²⁺ cations in the C₆H₆ and CCl₄ solutions of the polymer molecules (UO₂X₂)_p. The polymers exhibit tridentate-bridge coordination (I), which is not typical of (MX_n)_p salts where the phosphoryl oxygen atom forms two bonds with U(VI) atoms. When a few U(VI) atoms (≳7%) interact with donar additives, all POO group I change their coordination to the usual bidentate-bridge type, , resulting in a structural transformation of the polymer. The bridging POO group are responsible for the difference in the dimerization and trimerization constants and the constants of the subsequent addition of the monomer molecules UO₂X₂ to the polymer chain (UO₂X₂)_p. It is suggested that type I coordination of X⁻ to U(VI) is due to an extended bond between the 2p²-electrons of the phosphoryl oxygen atom of the X⁻ anion and a vacant f-orbital of the U(VI) atom (p_π−f_π interaction). This unusual type of bond between uranium (VI) and tributyl phosphate (TBP) phosphoryl oxygen was found earlier for the UO₂Cl₂·2TBP complex. Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturmoi Khimii, Vol. 35, No. 6, pp. 60–65, November–December, 1994. Translated by K. Shaposhnikova     

Ternary ion-association complexes between the indium(III) - 4-(2-pyridylazo)resorcinol anionic chelate and some tetrazolium cations

Complex formation and liquid-liquid extraction were studied in systems containing indium(III), 4-(2-pyridylazo)resorcinol (PAR), tetrazolium salt (TZS), water and chloroform. Two different TZS were used: 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT). The optimum conditions for extraction of In(III) as a ternary complex, (TT⁺)[In(PAR)₂] or (MTT⁺)[In(PAR)₂], were found: pH, extraction time, concentration of PAR and concentration of TZS. The constants of extraction (K_ex), constants of association (β), constants of distribution (K_D) and recovery factors (R%) were determined. The apparent molar absorptivities in chloroform were calculated to be ɛ′₅₂₀=6.6×10⁴ L mol⁻¹ cm⁻¹ and ɛ′₅₁₅=7.1×10⁴ L mol⁻¹ cm⁻¹ for the systems with TTC (I) and MTT (II), respectively. Beer’s law was obeyed for In(III) concentrations up to 3.4 μg mL⁻¹ in both the cases. The limits of detection (LOD=0.07 μg mL⁻¹ I and LOD=0.12 μg mL⁻¹ II), limits of quantification (LOQ=0.24 μg mL⁻¹ I and LOQ=0.41 μg mL⁻¹ II) and Sandell’s sensitivities (SS) were estimated as well.      

Benzidine and diphenylamine radical formation on the surface of NaY-zeolite and γ-alumina with and without V2O5

Solutions of benzidine and diphenylamine in benzene produce cation radicals on the surface of zeolite, -alumina and V₂O₅ doped alumina and zeolite. The sequence of the electron acceptor site strength on the surface is as follows:     

Synthesis and properties of bis(biphenyl)chromium(<Emphasis Type="SmallCaps">i</Emphasis>) 1,4-di(2-cyanoisopropyl)-1,4-dihydrofulleride and 1-(2-cyanoisopropyl)-1,2-dihydrofullerene

Radical-ion salts bis(biphenyl)chromium(i) 1,4-di(2-cyanoisopropyl)-1,4-dihydrofulleride [(Ph₂)₂Cr]^+·[1,4-(CMe₂CN)₂C₆₀]^−· and bis(biphenyl)chromium(i) 1-(2-cyanoisopropyl)-1,2-dihydrofulleride [(Ph₂)₂Cr]^+·[1,2-(CMe₂CN)(H)C₆₀]^−·, the salt bis(biphenyl)chromium(i) (2-cyanoisopropyl)fulleride [(Ph₂)₂Cr]^+·[(CMe₂CN)C₆₀]⁻, and neutral 1-(2-cyanoisopropyl)-1,2-dihydrofullerene 1,2-(CMe₂CN)(H)C₆₀ have been synthesized for the first time. The compounds [(Ph₂)₂Cr]^+·[1,4-(CMe₂CN)₂C₆₀]^−· and [(Ph₂)₂Cr]^+·[1,2-(CMe₂CN)(H)C₆₀]^−· decompose in THF to form [(Ph₂)₂Cr]^+·[(CMe₂CN)C₆₀]⁻, whose protonation affords 1,2-(CMe₂CN)(H)C₆₀. 1,4-Di(2-cyanoisopropyl)-1,4-dihydrofullerene 1,4-(CMe₂CN)₂C₆₀ and 1,2-(CMe₂CN)(H)C₆₀ are stable in vacuo up to 513 K. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1935–1939, September, 2008.