Analyse von Gemischen aus Tri-, Di- und Monophenylzinnverbindungen und anorganischem Zinn(IV)

Triphenyl tin compounds are extracted as (C₆H₅)₃SnOSn(C₆H₅)₃ by CHCl₃ or CH₂Cl₂ from aqueous solution of pH 8.5. Diphenyl tin compounds are separated by solvent extraction with PAN/CHCl₃, diphenylcarbazone/CHCl₃, dithizone/CHCl₃, α-benzoinoxime/CHCl₃, PAR/i-Pentanol etc. Monophenyl tin compounds are extracted by Tropolone/CHCl₃, and inorganic tin(IV) is separated by diethyl dithiocarbaminate/CHCl₃ from acidified solution of pH 4. Several thin-layer chromatographic methods are given. The separated compounds are determined by radiometric or new photometric methods.     

Darstellung und eigenschaften von diorganogermaniumdisulfinsäureestern

Diorganogermaniumdisulfinic esters of the type R₂Ge(O₂SR′)₂ (R = CH₃, R′ = CH₃, C₆H₅, p-CH₃C₆H₄; R = C₆H₅, R′ = CH₃, p-CH₃C₆H₄) which are sensitive to hydrolysis are obtained by reaction of the corresponding diorganogermanium dichlorides with anhydrous silver sulfinates. The newly prepared compounds are thoroughly investigated on the basis of their ¹H NMR, mass, IR and Raman spectra. The methyl ester (CH₃)₂Ge(O₂SCH₃)₂ is compared with the already known sulfinato complex of tin with the same formal composition.     

Investigation the chemical reactivity of positions N‐3, C‐5 and C6‐methyl group in biginelli type compounds and synthesis of new dihydropyrimidine derivatives

The compounds 5‐ethoxycarbonyl‐1,6‐dimethyl‐4‐(3‐nitrophenyl)‐3,4‐dihydropyrimidin‐2(lH)‐one (5) and 5‐ethoxycarbonyl‐1‐phenyl‐6‐methyl‐4‐(3‐nitrophenyl)‐3,4‐dihydropyrimidin‐2(lH)‐one (1) were prepared by the Biginelli condensation method and they converted to eight N‐3 substituted dihydropyrimidines using NaH and various electrophiles (ClCO₂Et, TsCl, Ac₂O, AcCl and PhCOCl). Compound (1) was mono‐brominated at the C₆‐methyl group using bromine solution. Reaction of the bromo derivative with amino nucleophiles such as methyl amine and cyclohexyl amine produced two pyrrolo‐pyrimidine derivatives. All the compounds except 5‐ethoxycarbonyl‐1‐phenyl‐6‐methyl‐4‐(3‐nitrophenyl)‐3,4‐dihydropyrimidin‐2(l_H)‐one ( 4 ) were purified by recrystallization methods. The structure of all the new compounds was confirmed using FT‐ir,¹H nmr, ¹³C nmr spectral and elemental analyses methods.     

Base-catalysed solvolysis of acylsilanes

Kinetic studies have been made of the hydrolysis of XC₆H₄COSiR₃ compounds (R = Me, Et, Ph) in a mixture of THF (3 vol.) and aqueous sodium hydroxide (1 vol.). The rates of cleavage of p-NO₂C₆H₄CH₂SiMe₃, C₆H₅COSiMe₂C₆H₅ and C₆H₅COSiMe₂C₆H₄Cl-p compounds under the same conditions have also been measured. Electron-attracting substituents on either side of the bond being broken lead to an increase in the rate. For the XC₆H₄COSiR₃ compounds, the effects of the substituents X correlate excellently with their Hammett σ constants (? = 3.5 and 2.5 for R = Me and Ph, respectively). The data are consistent with a mechanism in which the attack of the hydroxide ion occurs at the carbonyl C atom.     

Catalysis of the water gas shift reaction by cis -[Rh(CO)2(AMINE)2](PF6) complexes in an aqueous tetrabutylammonium hydrogensulfate solution

Rhodium(I) complexes, cis-[Rh(CO)₂(amine)₂](PF₆) (amine = 4-picoline, 3-picoline, 2-picoline, pyridine, 3,5-lutidine or 2,6-lutidine) dissolved in an aqueous solution of tetrabutylammonium hydrogensulfate (N(C₄H₉)₄HSO₄), catalyze the water-gas shift reaction (WGSR). The role of the coordinated amine on the catalytic activity was examined.     

An Electrochemical Investigation into a Series of Tricyanovinylated Pyrrole Moieties

The electrochemical behavior of three tri‐cyanovinylated pyrrole species namely, 2‐tricyanovinyl‐pyrrole (C₄H₄N? C₅N₃), 2‐tricyanovinyl‐N‐methylpyrrole (C₅H₆N? C₅N₃) and 2‐tricyanovinyl‐N‐phenylpyrrole (C₁₀H₈N? C₅N₃), has been studied. All compounds were found to exhibit both an irreversible oxidation at more positive potentials compared to the unsubstituted monomer species and a reversible reduction redox couple associated with reduction of the co‐ordinated cyano ligands. The latter reductions of the tricyanovinylated compounds to their radical anions at platinum, carbon and gold electrodes in acetonitrile solution have been studied by cyclic voltammetry, using a variety of supporting electrolytes. The half‐wave potentials for each compound were found to be dependent upon the supporting electrolyte but independent of the nature of the electrode surface. This is attributed to ion‐pairing between the anions and the alkali metal cations. The reduction based redox processes of C₁₀H₈N? C₅N₃ and C₅H₆N? C₅N₃ were found to be facile in nature and independent of both the nature of the electrolyte and electrode surface. However, the reduction of C₄H₄N? C₅N₃ was found to be irreversible in nature. Attempts were made to elucidate, by both electrochemical and spectroscopic means, the structure of the products obtained upon oxidation of the tricyanovinylated compounds.     

π-Cyclopentadienyls of nickel(II) IV. S-bonded organonickel compounds: s-sulfinato-and thiolato-nickel compounds

π-Cyclopentadienylbis(tri-n-butylphosphine)nickel chloride reacts with sodium benzenesulfinate and sodium p-toluenesulfinate in aqueous solution at room temperature to give π-cyclopentadienyl-S-(benzenesulfinato) (tri-n-butylphosphine)nickel, π-C₅H₅Ni(PBu₃)SO₂Ph and π-cyclopentadienyl-S-(p-toluenesulfinato)(tri-n-butylphosphine)nickel, π-C₅H₅Ni(PBu₃)SO₂C₆H₄CH₃-p,-respectively. It reacts similarly with sodium benzenethiolate and sodium α-toluenethiolate in aqueous solution at room temperature to give π-cyclopentadienyl(benzenethiolato)(tri-n-butylphosphine) nickel, π-C₅H₅Ni(PBu₃)SPh and π-cyclopentadienyl(α-toluenethiolate)(tri-n-butylphosphine)nickel, π-C₅H₅Ni(PBu₃)SCH₂Ph, respectively.     

Cumulative author index

For the compounds C₆H₅C₆H₄YC₆H₄C₆H₅ and C₆H₅C₆H₄YC₆H₄C₆H₄YC₆H₄C₆H₅ where Y is either Si(CH₃)₂ or CH₂, reduction potentials and p-band positions are reported. These data as well as the UV data for several phenyl derivatives are consistent with silicon blocking, to a large extent, conjugation (little or no through conjugation) of biphenyl moieties separated by Si(CH₃)₂groups.     

(Chloromethyl)thallium(III) compounds

Aryl(chloromethyl)thallium chlorides, Ar(ClCH₂)TlCl (Ar=C₆H₅, p-CH₃C₆H₄) have been prepared by treatment of arylthallium dichlorides with diazomethane. The derived carboxylates, Ar(ClCH₂)TlX, react with HgX₂ to give the dicarboxylates, (ClCH₂)TlX₂ (X = OCOCH₃, OCOC₃H₇-i) and with tetramethyltin to give CH₃(ClCH₂)TlX compounds. R(ClCH₂)TIX compounds (R = CH₃, C₆H₅, p-CH₃C₆H₄) undergo disproportionation in methanol to R₂TlX and (ClCH₂)₂TlX compounds.     

Reactions of dodecahydro-closo-dodecaboric acid with chitosan

A donor-acceptor interaction between H⁺-cations of dodecahydro-closo-dodecaboric acid and the amine group of chitosan results in the generation of chitosanium dodecahydro-closo-dodecaborate, (C₆O₄H₉NH₃)₂B₁₂H₁₂ — water-insoluble salt. The presence of four pairs of donor oxygen atoms in its composition makes for the existence of (C₆O₄H₉NH₃)₂B₁₂H₁₂× nH₂B₁₂H₁₂ (0 < n ≤ 4) compounds. When treating the latter with gaseos ammonia, the compounds of (C₆O₄H₉NH₃)₂B₁₂H₁₂×n(NH₄)₂B₁₂H₁₂ (0 < n ≤ 4) composition are formed. The individuality of the compounds was confirmed by IR and X-ray PE spectral studies, chemical and X-ray phase analyses, and thermogravimetry.     

The effects of isotopic substitution and competitive adsorption on the oxidation of aldehydes and alcohols at gold electrodes

The nature of the mechanism of the anodic oxidation of aldehydes in aqueous base on gold electrodes has been probed using isotopic substitution and competitive adsorption studies. A primary kinetic isotope effect of k_H/k_D=3?4 was observed upon substitution of deuterium for protium on the formyl group of benzaldehyde and cyclohexanecarboxaldehyde on gold in aqueous base using the techniques of cyclic voltammetry, rotating disc electrode voltammetry and chronoamperometry. Similar results are reported for the same aldehydes on a silver electrode, and also for the anodic oxidation of 2-propanol and 2-propanol-2-d on gold under similar conditions. Inhibition of the anodic cyclic voltammetric peak for benzaldehyde on gold by a variety of adsorbed species including CN^?, I^?, Br^?, (C₂H₅)₄N⁺ and diethylenetriamine is also described. These observations are used to propose a mechanism for the low potential oxidations of aldehydes and alcohols on gold involving a rate limiting dissociative adsorption step with cleavage of the α-carbon-hydrogen bond.     

Cyclopentadienyleisen-komplexe mit P(OR)3-liganden; Synthese und spektroskopische charakterisierung

Reactions of reactive cyclopentadienyliron complexes C₅H₅Fe(CO)₂I, [C₅H₅Fe(CO)₂THF]BF₄, [C₅H₅Fe(CO)((CH₃)₂S)₂]BF₄ and [C₅H₅Fe(p-(CH₃)₂C₆H₄)]PF₆ with P(OR)₃ as ligands (R = CH₃, C₂H₅, i-C₃H₇ and C₆H₅) lead to the formation of the complex compounds C₅H₅Fe(CO)_2?n(P(OR)₃)_nI and [C₅H₅Fe(CO)_3?n(P(OR)₃)_n]X (n = 1, 2 and n = 1–3, X = BF₄, PF₆). Spectroscopic investigations (IR, ¹H, ¹³C and ³¹P NMR) indicate an increase of electron density on the central metal with increasing substitution of CO groups by P(OR)₃ ligands. The stability of the compounds increase in the same way.     

Synthesis, structure, and activity evaluation of two silver(I) complexes as Helicobacter pylori urease inhibitors

Two silver(I) compounds, [Ag(R,R-hxn)](C₇H₄BrO₂) · 2H₂O (I) (Chxn = 1,2-diaminocyclohexane) and [Ag(C₅H₆N₂)₂]₂(C₈H₄O₄) · 10H₂O (II), were synthesized and complex I was structurally characterized by X-ray crystallography. Compound I contains a catena-(trans-1,2-diaminocyclohexane) silver polycation ([Ag(Chxn)]_∞) in a roughly linear fashion, while II possesses a linear-type silver monocation. Compounds I and II were evaluated for their inhibitory activities against Helicobacter pylori urease in vitro. Both were found to have strong inhibitory activities against H. pylori urease comparable to that of acetohydroxamic acid.     

Optisch aktive übergangsmetall-komplexe: LXXXIII. Konfigurationsstabile tetraedrische NiNi′CC′-cluster

The reaction of Ni(C₅H₅)₂ and Ni(C₅H₄COOCH₃)₂ with the acetylene (?)-(R)-C₆H₅CCCONHCH(CH₃)(C₆H₅)(C₆H₅), “CC′”, yields tetrahedral Ni₂C₂ clusters. Besides the compounds with two identical Ni corners (Ni₂CC′ types) also compounds with two different Ni corners (NiNi′CC′ types) are formed. These consist of two diastereomers which, for a given (R)-configuration in the acid amide substituent, differ only in the cluster chirality. They are separated chromatographically and turn out to be configurationally stable with respect to a change of the cluster chirality.     

Reactions of iridium and platinum complexes with N-sulfinyl compounds

The reactions of substituted N-sulfinylanilines with the complexes {Pt[P(C₆H₅₃]₂O₂} and {IrClCO[P(C₆H₅)₃]₂} have been reinvestigated. The former complex yields {Pt[P(C₆H₅)₃]₂SO₄} as the only isolable product in reactions with N-sulfinylaniline. In contrast to a previous report, Vaska's complex has been found not to react with C₆H₅NSO under anhydrous conditions. {Pt[P(C₆H₅)₃]₂-(C₂H₄)} reacts with N-sulfinyl compounds to give complexes of formula {Pt[P(C₆H₅)₃]₂-(RNSO)} where R = C₆H₅, p-O₂NC₆H₄, p-CH₃C₆H₄, or p-CH₃C₆H₄SO₂. {Pt[P(C₆H₅)₃]₃} reacts with C₆H₅NSO to give the same product obtained from reaction with the ethylene complex. Vaska's complex and its bromo analog form 1:1 adducts with p-O₂NC₆H₄NSO.     

Synthesis, crystal structures and in vitro antitumor activities of some arylantimony derivatives of analogues of demethylcantharimide

A series of novel arylantimony derivatives of analogues of demethylcantharimide with the formulae Ar_nSbL_(5−n) and Ar_nSbL^′_(5−n)(LH=N-hydroxy-demethyldehydrogencantharimide, L^′H=N-hydroxy-demethylcantharimide, n=3, 4; ArC₆H₅, 4-CH₃C₆H₄, 3-CH₃C₆H₄, 2-CH₃C₆H₄, 4-ClC₆H₄, 4-FC₆H₄) were synthesized and characterized by elemental analysis, IR, ¹H NMR and mass spectroscopy. The crystal structures of (C₆H₅)₄SbL, (4-CH₃C₆H₄)₃SbL₂ and (3-CH₃C₆H₄)₃SbL^′₂ were determined by X-ray diffraction. The in vitro antitumor activities of all compounds against six cancer cells are reported.     

Preparation and properties of new ferrocenyl heterobimetallic complexes with counterion dependent NLO responses

New ferrocenyl-based bimetallic cationic compounds of the type of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNRuCp(PPh₃)₂]X (X=PF₆, BF₄) and of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNFeCp(CO)₂]PF₆ have been obtained and characterized. The crystal structure of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNRuCp(PPh₃)₂]BF₄ has been established by means of X-ray diffractometry. The NLO responses of the compounds have been studied by the hyper-Rayleigh scattering technique and the hyperpolarizability is found to be dependent on the nature of the counterion.     

Organo group VB chemistry: Part VI. On the electric dipole moments of some substituted tertiary phenylphosphines, -arsines, -stibines and -bismuthines

The dipole moments of the following series of tertiary substituted aryl-group VB compounds were measured: (a) (C₆H₅)₃M and (XC₆H₄)₃M with M = P, As, Sb, Bi and X = 4-F, 4-Cl, 4-CH₃, 3-F, 3-Cl; and (b) (3-XC₆H₄)_3?n PR_n with R = C₆H₅, 4-FC₆H₄ and X = F, Cl. These experimental molecular moments are discussed as a consistent set of data that allows the calculation, within the framework of the vectorial additive method, of suitable group moments, bond moments and configurational parameters.     

Rhodium (II) compounds with functionalized metalated phosphines as bridging ligands

The reaction of Rh₂(O₂CCH₃)₄ · 2CH₃OH with the phosphine P(4-BrC₆H₄)₂(C₆H₅), 2, results in the formation of the monometalated compound Rh₂(O₂CCH₃)₃[PC] · 2CH₃CO₂H (PC representing a metalated P(4-BrC₆H₄)₂(C₆H₅)). The reaction involves selective metalation of the phosphine at one Br-substituted ring (12:1 isomer ratio). The reaction of Rh₂(O₂CCH₃)₃[(4-BrC₆H₃)P(4-BrC₆H₄)(C₆H₅)] · 2CH₃CO₂H, 4, with one additional mol of triphenylphosphine yields a mixture of two main stereoisomers Rh₂(O₂CCH₃)₂[(4-BrC₆H₃)P(4-BrC₆H₄)(C₆H₅)] [(C₆H₄)P(C₆H₅)₂] · 2CH₃CO₂H, 5a and 5b, that were isolated as pure compounds. These two compounds were resolved in the corresponding M and P enantiomers as trifluoroacetate derivatives that show good enantioselectivities in catalytic transformation of α-diazocarbonyl compounds.     

Organische Phosphorverbindungen XXXVIII. Darstellung und Eigenschaften von Tris-(dialkoxyphosphonyl-methyl)-, Tris-(alkoxyphosphinyl-methyl)-und Tris-(oxophosphoranyl-methyl)-phosphinsäureestern sowie der entsprechenden Säuren [1]

Tris-chloromethyl-phosphine oxide, (ClCH₂₎₃ P?O(I), is obtained by chlorination of (HOCH₂₎₃P?O with PCl₅ or (C₆H₅₎₃PCl₂, and also by oxidation of (CICH₂₎₃P?O and (ClCh₂₎₂(CH₃)P?O. High yields of tris-(dialkyloxyphosphonly-methyl)-phosphine oxides, [RO₂(O)PCH_2]2P?O (II) (R?CH₃, C₂H₅, iso-C₃H₇, n-C₄H₉, 2- ethyl-hexyl), tris (alkyloxyphosphinyl-methyl)-phosphine oxides, [R₂(O)PCH_2]3P?O(R = C₆H₅, CH₃) are obtained by heating tris-chloromethyl-phosphine oxides, [(RO) (R′) (O)PCH_2]3P?O (R = C₄H₉, R′? C₆H₅) and tris-(oxophosphoranyl-phosphine oxides with phosphites, phosphonites and phosphinites, respectively, at 170–180°C for several hours. Compounds II possess an extraordinarily high absorption capacity. Thus a warm. 2% solution of II (R = C₂H₅) in benzene solidifies completely on cooling so that no benzene can be poured off. Tris-dihydroxyphosphonyl-methyl)-phosphine oxide, [(HO)₂(O)PCH_2]3P?O, obtained by hydrolysis of II (R ? C₂H₅) with refluxing conc. HCl or by thermal decomposition of II (R ? iso-C₃H₇) at 190°, titrates in aqueous solution as a hexabasic acid with breaks at pH = 4,4 (three equivalents) and pH = 10,7 (three equivalents). It forms crystalline salts with amines, alkali and alkaline earth metals, and is an excellent chelating agent. The ¹H- and ^31?P-NMR. spectra of all the compounds prepared are discussed.