Tetrachloromethane Solution Research Articles

A Window into the Workings of anti-B18H22 Luminescence-Blue-Fluorescent Isomeric Pair 3,3'-Cl2-B18H20 and 3,4'-Cl2-B18H20 (and Others).

The action of AlCl3 on room-temperature tetrachloromethane solutions of anti-B18H22 (1) results in a mixture of fluorescent isomers, 3,3'-Cl2-B18H20 (2) and 3,4'-Cl2-B18H20 (3), together isolated in a 76% yield. Compounds 2 and 3 are capable of the stable emission of blue light under UV-excitation. In addition, small amounts of other dichlorinated isomers, 4,4'-Cl2-B18H20 (4), 3,1'-Cl2-B18H20 (5), and 7,3'-Cl2-B18H20 (6) were isolated, along with blue-fluorescent monochlorinated derivatives, 3-Cl-B18H21 (7) and 4-Cl-B18H21 (8), and trichlorinated species 3,4,3'-Cl3-B18H19 (9) and 3,4,4'-Cl3-B18H19 (10). The molecular structures of these new chlorinated derivatives of octadecaborane are delineated, and the photophysics of some of these species are discussed in the context of the influence that chlorination bears on the luminescence of anti-B18H22. In particular, this study produces important information on the effect that the cluster position of these substitutions has on luminescence quantum yields and excited-state lifetimes.

Pathomorphological changes in the organs of laboratory animals with experimental liver cirrhosis

Objective. Develop an experimental model of liver cirrhosis and describe pathomorphological changes in organs and tissues of laboratory animals.Materials and methods. Liver cirrhosis was simulated on 11 sexually mature Wistar male white rats. The control group consisted of 12 healthy laboratory animals. Acute toxic liver injury resulting in cirrhosis was induced by intraperitoneal injection of 50% tetrachloromethane (CCl4) solution on olive oil on the first day of the experiment in the dosage of 0.1 ml CCl4 + 0.4 ml olive oil per 100 g of the animal body weight, on the second day of the experiment 0.3 ml CCl4 + 0.2 ml olive oil per 100 g of the animal body weight. To synergize and potentiate the hepatotoxic effect of CCl4, animals had 10% ethanol solution freely available daily. The duration of the experiment was 65 days. Clinical and laboratory parameters were evaluated, histological evaluation of the preparations was performed. The obtained data were compared with the control group of animals.Results. Reproducibility of the model was 82% (9 animals). The indicator of lymphocyte blabbing index showed the development of liver cirrhosis in animals of the experimental group. Comprehensive morphological confirmation of the developed liver cirrhosis was obtained.Conclusion. The proposed methodology of liver cirrhosis formation correlates with pathomorphological changes in lymphocyte cell wall, changes in liver tissue and internal organs in human liver cirrhosis.

Effect of oxidized dextran on rat hepatocytes in toxic hepatosis of mixed etiology

The aim of research was to study the oxidized dextran protection effect against hepatic parenchyma defect at combinated acute and chronic toxicity of ethyl alcohol and tetrachloromethane solutions. Materials and methods. 150 male Wistar rats were injected by toxicants with intraperitoneal administration: 50 % CCl4 in olive oil solution and 5 % oxidized dextran (OD) aqueous solution with molecular weight 40 kDa and peroral 6.5 % ethyl alcohol aqueous solution. Tetrachloromethane was injected once a day, and then only ethyl alcohol aqueous solution was administrated 1 time per day during 3 days. The ethyl alcohol aqueous solution was not administered on the days of the of tetrachlomethane and OD injections. OD has been administered from the 1st day of the toxicants injection till 60 days. OD without toxicants has been injected for the next 30 days. Results and discussion. In animals that were injected only with toxicants, hepatocytes were in a state of vacuolar dystrophy, which occupied slightly more than 40 % of the organ parenchyma, and hepatocytes in a state of necrosis, which occupied from 37 to 28 % of the parenchyma at different periods of observation. The OD inclusion in the scheme for the prevention of necrotic complications reduced them from 3 to 4 times more than in animals that did not receive OD. The data obtained indicate the OD high hepatoprotective effectiveness.

Dominance of eclipsed ferrocene conformer in solutions revealed by the IR spectra between 400 and 500 cm-1

A combined Fourier transform infrared (FTIR) spectra of ferrocene (Fc) and density functional theory (DFT) based quantum mechanical calculations confirmed the dominance of the eclipsed Fc conformer in the fingerprint region of 400–500 cm−1 in solutions. Solution IR spectra of Fc measured in acetonitrile (ACN, ε = 35.69), dichloromethane (DCM, ε = 8.93), tetrahydrofuran (THF, ε = 7.43) and dioxane (DOX, ε = 2.21) show two well-defined bands in the 480-500 cm−1 region with the higher-wavenumber band higher in intensity. The band profile agrees well with the earlier IR spectra of Lippincott and Nelson (1958) in tetrachloromethane solution as well as more recent measurement in dichloromethane solution of Duhović and Diaconescu (2013). DFT based quantum mechanical calculations predict that the eclipsed (D5h) Fc conformer is lower in energy than the staggered (D5d) conformer and that the room-temperature solution spectrum of Fc is dominated by that of the D5h form (Best et al., 2016). The present study confirms that solvent effects enhanced the dominance of the D5h Fc conformer which resulted in switch of the IR profile patterns in 400–500 cm−1, from low-wavenumber band higher in intensity pattern in gas phase to higher-wavenumber band higher in intensity in solutions. It further suggests that the effects of solvents on the IR spectra of Fc in this region are small and the solvent model effects are also small for the IR spectrum in the region of 400–500 cm−1 of Fc.

Estimation of the infl uence of cytochrome P450 induction on carbon tetrachloride genotoxicity in vitro

Introduction. One of the stages of the pathogenesis of the toxic eff ect of carbon tetrachloride is the formation of compounds of reactive oxygen species with DNA, leading to the modifi cation of nitrogenous bases. The frequency of formation of nucleotides modifi ed by nitrogenous bases correlates with the number of single-and double-chain breaks of deoxyribonucleic acid (DNA) molecules. The initiator of the formation of active forms of oxygen and lipid peroxidation in liver cells upon receipt of carbon tetrachloride is a trichloromethyl radical formed during biotransformation by microsomal enzymes of cytochrome P450.The aim of the study was to analyze the changes in the genotoxicity of carbon tetrachloride in hepatocytes at normal and increased activity of cytochrome P450 caused by the infl uence of an inductor (sovol).Materials and methods. Evaluation of genotoxicity is performed by the method of DNA-comets aft er gavage with carbon tetrachloride culture of mouse hepatocytes МН22а in 96-well microplates without the induction of cytochrome P450 and chemical induction of cytochrome P450 by sovol. Determination of DNA content in comet tail (%), comet tail length (μm) and tail moment was performed in ImageJ 1.48. Statistical analysis of the results was performed in the program SPSS Statistics 21.Results: Experimental data on the genotoxic eff ect of carbon tetrachloride on hepatocytes of the MN–22A cell line without induction of cytochrome P450 and chemical induction of cytochrome P450 by sovol are presented. It was found that 0.5 mm solution of carbon tetrachloride in 1 hour aft er addition to the culture medium is genotoxic for hepatocytes MH–22a without the use of sovol (p<0.001). Th e lack of determined using the method of DNA-comet signs of genotoxicity of 5 mm carbon tetrachloride (p>0.05) in the culture medium, probably due to the transition of the cells into a state of parametros. Genotoxic eff ect is not detected by DNA comet aft er 3 and 24 hours of incubation of hepatocytes MN–22A with 0.5 and 5 mm solutions of carbon tetrachloride without preincubation with sovol (p>0.05), which may indicate repair of the damage. Aft er 72 hours of preliminary incubation of hepatocytes with sovol and the followin g four-hour cell priming with 2.5 mm tetrachloromethane solution, higher values of the parameters of DNA comets are observed than when seeding with tetrachloromethane without incubation with sovol (p<0.05).Conclusions: According to the results of the study 72 hours of cytochrome P450 induction by sovol increases the genotoxicity of carbon tetrachloride in vitro, compared with 24 h of inductor exposure, which may indirectly indicate a higher level of formed reactive oxygen species caused by increased activity of cytochrome P450 enzymes.

CHANGES OF SUBCIRCADIAN RHYTHMS OF INDICATORS OF THE PROOXIDANT AND ANTIOXIDANT DEFENSE SYSTEM IN THE KIDNEY OF RATS WITH TETRACHLOROMETHANE INTOXICATION AND CORRECTION OF MELATONIN

The subcircandian rhythms of TBA-reactive products content, aldehyde and ketone derivatives of DNFH, the activity of catalase in rat kidneys with tetrachloromethane intoxication on the conditions of experimental equality have been investigated. It was shown that intoxication with tetrachloromethane causes desynchronization of circadian rhythms of the studied indices. Five-single administration to intoxicated animals of melatonin on the conditions of experimental equality leads to the restoration of rhythms and the correction of absolute values of the investigated variables.The aim of the study. To investigate the effect of melatonin on subcircadian rhythms of free radical oxidation indicators in rat kidneys with tetrachloromethane intoxication on the conditions of experimental equality.Materials and methods. Research conducted on white nonlinear sexually mature male rats weighing 180 ± 10 g, which were kept under vivarium conditions with constant temperature (+200С) regime and artificial lighting with an intensity of 1500 lux in a mode of 12 hours of light up to 12 hours of darkness (12L:12D) throughout the experiment. After a 7-day simulation of light conditions the animals were separated into groups: 1st group – a control group of animals (intact animals); 2nd group – animals that were intradermally administered of melatonin solution; 3rd group – animals that were intragastric administered twice of tetrachloromethane solution; 4th group – intoxicated tetrachloromethane animals were intragastric administered of melatonin solution. Euthanasia of animals was carried out by decapitation under a light etheric anesthesia at 8.00, 12.00, 16.00 and at 20.00 o’clock. In the post-nuclear supernatants of the 5%-s kidney homogenates were determined: the content of TBA-reactive products, aldehyde and ketone derivatives of DNFH, catalase activity. The received digital data was processed statistically by the method of variation statistics using Student's t-test.Results. The state of free radical oxidation of lipids and proteins in rat kidneys under artificial lighting with an intensity of 1500 lux from 8.00 to 20.00 hr fluctuated within one indicator with an average value for the content of the TBA-reactive products – 41,1±1,59 µmol/g of tissue and for the content of the aldehyde and ketone derivatives of DNFH – 24,6±1,23 oz/g of tissue. Poisoning of animals with tetrachloromethane leads to increased oxidation of lipids and proteins in the ratkidneys at 16.00 h – forming a subcircadian rhythms with a pronounced maximum. Administration of melatonin to rats affected by tetrachloromethane on the conditions of experimental equality has led to a decrease in the absolute values of the content of free radical oxidation products of lipids and proteins in the kidney of animals during the day and has led to the restoration of the structure of subcircadian rhythms of the corresponding indices. The catalase (CAT) activity on the conditions of experimental equality acquired maximum values at 20.00 h (20,9±0,45 μmol/min/g of tissue), and the minimum – 19,9±0,52 μmol/min/g of tissue was at 8.00 and 16.00 h. In the conditions of toxic lesions with tetrachloromethane a sharp decrease on average by 45% in the activity of catalase was observed. The administration of melatonin resulted in an increase in the absolute values of activity of catalase in rat kidneys in comparison with the indicators of a group of animals which were intoxicated with CCl4 on average by 30%.Conclusions. 1. On the conditions of experimental equality under the artificial lighting with an intensity of 1500 lux subcircadian rhythms of the main indicators of pro- / antioxidant protection during light day in the rat kidneys have a small amplitude of oscillations. 2. Inoxication of rats with tetrachloromethane caused desinchrosis of indicators of free radical oxidation of macromolecules in the kidneys. 3. Five-single administration of melatonin has led to the restoration of the subcircadian rhythms of the investigated indicators.

Investigation of Ageing in Bitumen Using Fluorescence Spectrum.

Bitumen ageing is a very complex process and poses a threat to the performance of pavements. In the present work, a fluorescence spectrophotometer was employed to research the change rule of components and the structure of bitumen after the ageing process. The Thin Film Oven Test (TFOT) and Ultraviolet (UV) light treatment were carried out as ageing methods. The properties and components of bitumen were tested before and after aging. The 2D and 3D fluorescence spectra of bitumen were analyzed. The vector of fluorescence peak was calculated for evaluating the ageing process. The results indicated that the ideal concentration of bitumen- tetrachloromethane solution was 0.1 g/L or smaller for avoiding the fluorescence quenching. The coordinates of fluorescent peak appeared “blue-shift” after ageing due to the change of aromatics. In addition, bitumen has already occurred serious ageing when the magnitude of a vector is more than 36.

ДОСЛІДЖЕННЯ ГЕПАТОПРОТЕКТОРНОЇ АКТИВНОСТІ РІДКОГО ЕКСТРАКТУ ТРАВИ ЧАБЕРУ САДОВОГО ПРИ ТЕТРАХЛОРМЕТАНОВОМУ ГЕПАТИТІ

Мета роботи. Вивчити гепатопротекторну активність рідкого екстракту трави чаберу садового (Sаturejа hortensis L.) при експериментальному гострому тетрахлорметановому гепатиті.Матеріали і методи. Рідкий екстракт виготовлено шляхом послідовної екстракції подрібненої трави чаберу садового спиртом етиловим (70 %, 50 % та 30 %) з наступним об’єднанням витягів та їх концентруванням; його дозування здійснювали в перерахунку на сухий залишок. Для моделювання гепатиту щурам дворазового вводили 50 % олійний розчин тетрахлорметану у дозі 1 мл/кг маси тіла тварин. Для вивчення гепатопротекторної дії рідкого екстракту трави чаберу садового були вибрані дози 50 мг/кг, 100 мг/кг і 200 мг/кг маси тіла тварин; як препарат порівняння використовували «Силібор» у дозі 50 мг/кг.Результати й обговорення. Введення піддослідним тваринам рідкого екстракту трави чаберу садового з профілактичною метою на тлі тетрахлорметанового отруєння значно зменшило загальні прояви ураження. У ході експерименту вижили всі щури, які отримували екстракт, що вказує на перспективність вивчення його гепатопротекторної дії. Найбільш вірогідні зміни у досліджуваних біохімічних показниках організму щурів встановлено при використанні екстракту у дозі 200 мг/кг: за впливом на вміст малонового діальдегіду, молекул середньої маси та коефіцієнт маси печінки досліджуваний екстракт достовірно не відрізнявся від референс-препарату «Силібор», а за такими біохімічними показниками, як вміст загального білка і активністю супероксиддисмутази достовірно його перевершував. Використання доз екстракту 50 мг/кг і 100 мг/кг проявляло достовірний позитивний ефект тільки на деякі досліджувані показники уражених тварин.Висновки. Профілактичне введення рідкого екстракту трави чаберу садового у дозі 200 мг/кг ураженим тетрахлорметаном щурам суттєво знижувало інтенсивніть ураження печінки порівняно з контрольною патологією.

A comparative study of singlet-oxygen generation by С60 and С70 fullerenes

The results of comparative investigations of singlet-oxygen generation by С60 and С70 fullerenes in tetrachloromethane solutions, aqueous suspensions, and solid-phase powders of fullerenes optically excited by cw diode arrays with different wavelengths and by pulsed xenon lamps with a band filter are presented. The measurements were performed by recording singlet-oxygen phosphorescence at the O2(1Δg)–O2(3Σg) transition (λ = 1270 nm).

Influence of the strength of polarizing electric field on free relaxation of electric birefringence in poly(butyl-isocyanate) solutions

Free relaxation of electric birefringence in tetrachloromethane solution of high molecular weight poly(butyl-isocyanate) was studied. The effect of electric field strength on the average relaxation time was observed. The relaxation spectrum was analyzed using the Rouse and Zimm theories. With increase in the electric field strength, the contribution of fast (deformation) relaxation modes also increased significantly. It is assumed that certain changes in intramolecular mobility occur under the influence of electric field.

Study of “Racemic Compound-Like” Behavior of Diastereomeric Mixture of Pinanyl Sulfoxides by X-Ray Diffraction, IR Spectroscopy, and DFT Calculations

The oxidation of a β-hydroxysulfide in the pinane series by use of m-chloroperbenzoic acid resulted in the formation of the corresponding β-hydroxysulfoxide as a mixture of two diastereomers in 4:5 ratio. According to single-crystal X-ray diffraction (XRD) results, it is established that the diastereomeric mixture of sulfoxides crystallizes in the “racemic compound-like” manner under formation of asymmetric dimers through S=O··H–O interactions. This asymmetric dimer formed from diastereomeric molecules is a structural unit in both crystal modifications, the triclinic and the monoclinic one. The behavior of the diastereomeric mixture of pinane derived sulfoxides in crystals, melts and in tetrachloromethane solutions was studied by IR spectroscopy. The density functional theory (DFT) method with 6-31G (d, p) basis set was used to calculate the optimized geometrical parameters and vibrational frequencies of different associates in solutions. The calculated vibrational frequencies are compared with experimental IR spectra.

Ab Initio and Density Functional Predictions of Solvation Free Energies of Cyclic Polyethers (CH2CH2O)n (n=2,6) in Aqueous and Tetrachloromethane Solutions

Solvation free energies ΔGsoltot of cyclic polyethers (CH2CH2O)n (n=2,6) in aqueous and tetrachloromethane solutions have been calculated at HF, MP2 and B3LYP/6-311G (d,p) levels of theory using CPCM, IEFPCM and SMD implicit solvation models. It has been found that ΔGsoltot are negative for both solvents, they increase linearly with system sizes and they are more important in water solution. The electrostatic contributions to the solvation free energies ΔGsolele are also more important in water because of their polar nature. In water, CPCM and IEFPCM models give a close values, which are slightly different from SMD values. In tetrachloromethane solvent CPCM model seems overestimate ΔGsolele. For both solvents the non-electrostatic contributions to the solvation free energies ΔGsoln-ele provided by SMD are remarkably different to those given by CPCM and IEFPCM models.

Acidity of ortho-substituted benzoic acids: an infrared and theoretical study of the intramolecular hydrogen bonds

The structures of ortho-substituted benzoic acids with substituents bearing hydrogen atoms (OH, NH2, COOH and SO2NH2) were investigated by means of IR spectroscopy and of density functional theory at the B3LYP/6-311 + G(d,p) level. All possible conformations, hydrogen bonds, tautomeric forms and zwitterions were taken into consideration and particular attention was given to intramolecular H-bonds and their effect on acidity. Strong H-bonds in the anions of all four acids, were revealed by calculations. In three cases they were confirmed by the IR spectra of the tetrabutylammonium salts in tetrachloromethane solution, while the salt of 1,2-benzenedicarboxylic acid was not sufficiently soluble. The H-bonds are of different strengths but in all cases they are the main cause of the strengthened acidity of these acids in the gas phase and also in solution, although their effect is opposed by weaker H-bonds present in the undissociated acid molecules. The substituent effect on the acidity was evaluated in terms of isodesmic reactions, separately in the acid molecules and in the anions. While the acidity of the 2-OH and 2-NH2 acids is determined essentially by the H-bonds, that of the 2-COOH and 2-SO2NH2 acids is strengthened by the polar effect operating in the undissociated molecule in addition to the H-bond in the anion. The steric inhibition of resonance (SIR), estimated from model conformations with fixed torsional angles, is of little importance. This analysis goes significantly beyond the classical explanation obtained from the acidities in solution but essentially conforms with it.

Donor-Acceptor Complexes of Sulfur Trioxide with 1,4-Dioxane and Their Crystal Structures

Crystal and molecular structure of adducts C4H8O2·SO3 and C4H8O2·2SO3 were determined by X-ray structure analysis and Raman spectroscopy. Both compounds crystallize from excess of 1,4-dioxane as solvate C4H8O2·SO3·C4H8O2, which was characterized by the same methods. Conditions for preparation of all the three compounds in high purity and good yields were optimized. Solvates C4H8O2·H2SO4 and C4H8O2·H2S2O7 were identified among products of self-decomposition of C4H8O2·SO3 and C4H8O2·2SO3 in tetrachloromethane solution, respectively.

Calorimetric determination of hydrogen‐bonding enthalpy for neat aliphatic alcohols

AbstractHydrogen bonding in pure aliphatic alcohols is investigated using a novel calorimetric approach. Average enthalpies of hydrogen bonding were determined for methanol, ethanol, propan‐1‐ol, propan‐2‐ol, butan‐1‐ol, hexan‐1‐ol and octan‐1‐ol. For all the studied alcohols except methanol the average hydrogen‐bonding enthalpies fall in the range from −16.9 to −17.7 kJ mol−1. A slightly smaller value of −15.1 kJ mol−1 was observed for methanol. From the enthalpies of the specific interactions of the alcohols and chloroform (as proton donors) formed with the alcohols and diethyl ether (as proton acceptors), the dimerization enthalpies were determined for the investigated alcohols: −8.6 ± 0.7 kJ mol−1. The specific interaction and dimerization enthalpies obtained are concurrent with the Badger–Bauer rule and the hydrogen‐bond cooperativity effects. The calorimetric data obtained are supported by literature Fourier transform infrared data on dimer and multimer formation for ethanol and octan‐1‐ol in tetrachloromethane solution. Copyright © 2005 John Wiley & Sons, Ltd.

Volumetric properties of tetraphenylporphyrin and some of its alkoxy and tert-butyl derivatives in tetrachloromethane solutions

Densities, apparent molar volumes, and partial molar volumes, V 2 0, of tetraphenylporphyrin, H 2TPP; meso-tetra-4-alkoxyphenyl porphyrin derivatives, H 2T(4-OC n H 2 n+1 )PP (where n=4, 6, 8, 10, 12, 16); meso-tetra-4- tert-butylphenyl porphyrin, H 2T(4-tBu)PP; meso-tetra-3,5-ditert-butylphenyl porphyrin, H 2T(3,5-tBu)PP, in tetrachloromethane (TCM) solutions at 25 °C were determined. For TCM and benzene solutions of the compounds examined, relationship Δ K=K 2− K 1 was established as a function of van der Waals volume V 2 W, where K 2= V 2 W/ V 2 0 and K 1= V 1 W/ V 1* represent the packing coefficients of the solute and the solvent ( V 1* is molar volume of solvent), respectively. The resulting correlations were compared with the correlations established for members of various homologous series like n-alkanes, cycloalkanes, crown-ethers, cage structures. The Δ K-value was found to be closely related to the geometry of the solute molecule. Relationships are also given which relate V 2 0 with the number n of the structural repeating units (methylene groups) in compounds H 2T(4-OC n H 2 n+1 )PP, n-alkanes, cycloalkanes, and crown-ethers. An attempt was made to interpret the solvation properties of the solutions of individual compounds in the homologous series and also the similarities and differences between the homologous series.

Conformation of Aromatic Carbonyl Derivatives: An Infrared Study

Infrared spectra of 14 methyl- and polymethyl-substituted acetophenones and of 14 equally substituted methyl benzoates were investigated in the carbonyl region in tetrachloromethane solution and correlated with their conformation. The ν(C=O) frequency depends moderately on the inductive effect of substituents and more sensitively on the steric effect of ortho substituents. Steric effects are not simply related to the torsion angle ϕ (calculated by the density functional theory) but are better described by dividing the methyl substituents into three classes: nonplanar derivatives with methyl groups in the two ortho positions, slightly nonplanar derivatives with two methyl groups in the positions 2 and 3 (buttressing effect), and the remaining derivatives existing in two equilibrium planar conformations. Eleven various physical properties of methyl-substituted acetophenones, measured or calculated previously, were now correlated by principal component analysis (PCA). Two components are necessary to explain 93% of variance; they relate roughly to the steric and inductive effects. Steric effect affects all properties while inductive effect is of importance mainly for the gas-phase basicities and wavelengths in the UV spectra. Both can be separated very effectively using the classic comparison of ortho and para derivatives; in this way, the steric effect is isolated and in a subsequent PCA only one component is sufficient to explain 94% of variance.

Certified reference samples of tetrachloromethane, tetrachloroethylene, and chlorophenol solutions

A procedure was proposed for the metrological certification of reference samples (RS) of solutions of organic compounds. The procedure consists in the determination of performance characteristics of RSs using the developed and certified procedures for the determination of mass concentrations by gas chromatography with flame ionization detection using internal standards. The selection of the internal standards and calibration procedures and the calculation of the errors of determination are considered. Certified reference samples (CRS) of tetrachloromethane, tetrachloroethylene, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol solutions in ethanol are developed for the quality control of drinking water

Substituent Effects on Conformational Equilibria: Substituted Thiobenzanilides

Infrared absorption spectra of 38 thiobenzanilides in tetrachloromethane solutions were recorded in the ν(N-H) region. From the integrated absorption intensity of the computer-resolved N-H bands, the abundance of the Z and E conformations was calculated. The values of pertinent log KC depend on substitution in an unexpected way which cannot be described by the Hammett equation or by any other known type of modified constants σ. The only regularity observed is that the substituent effects from the two benzene rings of thioanilide are additive with a remarkable precision. The ν(N-H) frequencies are not much sensitive to substitution and the dependence is not simple: only ν(N-H) of the E conformer depend on substitution in a regular way.

Tin(IV) and organotin(IV) derivatives of novel β-diketones: II. Mono- and diaryltin(IV) complexes of 1-phenyl-3-methyl-4-R(CO)-pyrazol-5-one (R=CCl 3, OCH 3, OC 2H 5). Crystal and molecular structure of trans-dibenzylbis(1-phenyl-3-methyl-4-methoxycarbonyl-pyrazolon-5-ato)tin(IV), (C 7H 7) 2Sn(Q OMe) 2

A series of new tin(IV) and organotin(IV) derivatives has been synthesized. In basic (triethylamine) chloroform solution five- [R 2SnCl(Q *)] and six-coordinate [R 2Sn(Q *) 2] tin(IV) derivatives (HQ *=1-phenyl-3-methyl-4-trichloroacetylpyrazol-5-one; R=Ph, Bz) are obtained. In basic (KOH) alcoholic R′OH solution (R′=Me, Et) [R 2Sn( Q O R ′ ) 2] and [RSnCl 2( Q O R ′ )] derivatives (Q OR=1-phenyl-3-methyl-4-alkoxycarbonyl-pyrazolon-5-ato) are obtained, upon cleavage of the C–CCl 3 bond in the starting HQ * donor. From interaction between HQ * and SnCl 4 in refluxing dichloromethane the adduct SnCl 4(HQ *) was isolated. Additionally the donor HQ * reacts with RSnCl 3 (R=Ph, Bu n) in basic (triethylamine) tetrachloromethane solution to form the salt-like products [Et 3NH] +[RSnCl 3(Q *)] −. All the compounds were characterized by analytical and spectral (IR, far-IR, 1H, 13C and 119Sn NMR) data. The diffraction study of the complex Bz 2Sn(Q OMe) 2 shows a six-coordinate tin in a distorted octahedral frame, with the Bz groups trans to each other. The Bz–Sn–Bz bond angle is 164.5(4)° and the Sn–O distances are 2.105(6) and 2.359(7) Å in one ligand and 2.109(7) and 2.329(7) Å in the other. We find that in bis(pyrazolonate)diorganotin complexes structural features such as bite angle, difference of Sn–O bond length and O–Sn–O bond angles are functions of the organometallic C–Sn–C bond angle.