Abstract  Using biomass-derived ethylene glycol (bio-EG) to synthesize poly(ethylene terephthalate) (PET) is of notable significance for alleviating the dependence on fossil energy resources. Bio-EG readily contains a small amount of miscellaneous diols, which derive from the side reactions in the catalytic conversion of biomass. To disclose the effects of miscellaneous diols on the synthesis and properties of PET, EG feedstock containing four 1,2-diols, i.e., 1,2-propylene glycol, 1,2-butanediol, 1,2-pentanediol, and 1,2-hexanediol at 0-10% concentrations was used for the synthesis of PET. The molecular weights, intrinsic viscosities, and thermal and mechanical properties of obtained PET materials were measured. It was found that when the overall content of miscellaneous diols in EG was lower than 5%, the molecular weights and thermal properties of the prepared PET materials were very similar to that of PET synthesized from pure EG. The miscellaneous diols were less likely to be incorporated into PET resin because of the steric hindrance of the alkyl group in diols to the esterification and polycondensation reactions. Instead, they preferred to undergo dehydration reactions to form low-boiling-point aldehydes and hemiacetals, which could be removed from the reaction system during the reactions. Three bio-EG samples at purities of 99.9, 98.5, and 95.8 wt % were used for the bio-PET synthesis. Transparent and colorless bio-PET samples were obtained, demonstrating that the presence of miscellaneous diols does not have negative effects on the color quality of PET. The physical properties of bio-PET prepared with bio-EG at a purity of higher than 98 wt % were nearly the same as those of PET derived from pure EG. At a lower bio-EG purity of 95.8 wt %, the tensile strength of the obtained bio-PET sample was slightly decreased. The comprehensive results of property characterization show that bio-PET materials prepared with bio-EG at purity higher than 95 wt % could be used as widely as the conventional petro-PET resin without notable deterioration in their performance.

Abstract  To study the potential for delayed Type IV dermal sensitivity of a new preservative system containing 1,2-hexanediol and caprylyl glycol, 200-subject repeat insult patch tests were performed with a 15% mixture of 1,2-hexanediol and caprylyl glycol (equal parts of the 2 ingredients) in carbomer gel and a cosmetic formulation at an actual use concentration. No delayed Type IV hypersensitivity reactions were observed.

Abstract  Atmospheric aerosol particles are often partially or completely composed of inorganic salts, such as ammonium sulfate and sodium chloride, and therefore exhibit hygroscopic properties. Many inorganic salts have well-defined deliquescence and efflorescence points at which they take up and lose water, respectively. Field measurements have shown that atmospheric aerosols are not typically pure inorganic salt, instead, they often also contain organic species. There is ample evidence from laboratory studies that suggests that mixed particles exist in a phase-separated state, with an aqueous inorganic core and organic shell. Although phase separation has not been measured in situ, there is no reason it would not also take place in the atmosphere. Here, we investigate the deliquescence and efflorescence points, phase separation and ability to exchange gas-phase components of mixed organic and inorganic aerosol using a flow tube coupled with FTIR (Fourier transform infrared) spectroscopy. Ammonium sulfate aerosol mixed with organic polyols with different O : C ratios, including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and 1,5-pentanediol have been investigated. Those constituents correspond to materials found in the atmosphere in great abundance and, therefore, particles prepared in this study should mimic atmospheric mixed-phase aerosol particles. Some results of this study tend to be in agreement with previous microscopy experiments, but others, such as phase separation properties of 1,2,6-hexanetriol, do not agree with previous work. Because the particles studied in this experiment are of a smaller size than those used in microscopy studies, the discrepancies found could be a size-related effect.

Abstract  The micelle formation process for a typical anionic surfactant. sodium dodecyl sulfate, and a typical cationic surfactant, dodecyltrimethylammonium bromide, has been investigated in a series of mixed solvents consisting of different concentrations of isomeric hexanediols (1,2-hexanediol and 1,6-hexanediol) in water. The critical micelle concentrations and the degrees of counterion dissociation of the mixed micelles were obtained from conductance experiments. Luminescence probing experiments have been used to determine the concentration of micelles in solution and, hence, the micellar aggregation numbers of the surfactants in the mixed solvent systems. The alcohol aggregation numbers were determined by combining the partition coefficients (obtained using NMR paramagnetic relaxation enhancement experiments) with the micellar concentrations from the luminescence probing experiments. All these results are interpreted in terms of the difference in the interaction of the isomeric hexanediols with the surfactant as a function of the position of the hydroxyl groups on the six-carbon chain of the alcohol.

Abstract  Long chain aliphatic 1,2-diols like 1,2-hexanediol and 1,2-octanediol can be converted to the corresponding alpha-hydroxy-alkanoates with total chemoselectivity, in an oxidation catalyzed by an aqueous gold sol under O-2 atmosphere. The sol is stabilized with poly(vinylalcohol), and the reaction is performed in alcohol solvents. Two methods are proposed for the efficient recycling of the colloidal Au catalyst. Firstly a solvent-resistant membrane filtration can be applied. As the membrane material, poly(dimethylsiloxane) is chosen. Secondly, in appropriate conditions, the reaction proceeds in the liquid biphasic mode, and the aqueous Au sol can be recycled by phase separation. Using either of both approaches, the colloidal stability and catalytic activity can be preserved over several recycles.

Abstract  Background: Traditional preservation systems currently used in cosmetic and skin care products are safe and effective. New ingredients with similar efficacy are continually being introduced to fulfill this function. Objective: To study the potential for delayed type IV allergic hypersensitivity and irritation of a new preservative system containing 1,2-hexanediol and caprylyl glycol. Methods: A 200-subject repeat insult patch test (RIPT) was performed. A 15% mixture of 1,2-hexanediol and caprylyl glycol (equal parts of the two ingredients) in carbomer gel was placed under a series of 9 continuous occlusive induction patches, each 48 hours in duration. Three induction patches were applied each week, for a total of 3 weeks. Following a 10-day rest period during which no patches were applied, a single challenge application using the same mixture was applied and left on for 48 hours and read at 48 and 72 hours postapplication. A cosmetic formulation containing this same preservation system at an actual use concentration was tested by the same RIPT protocol. Results: Two hundred and twelve subjects completed the study. One hundred and sixty-eight were female and 44 were male ranging in age from 18 to 70 years. No reactions were seen during the induction or challenge phases. An additional 212 subjects were enrolled in a separate RIPT that evaluated the cosmetic formulation containing the same preservation system. No delayed type IV allergic hypersensitivity or irritation reactions were observed. Conclusion: A new preservative system utilizing 1,2-hexanediol and caprylyl glycol did not induce delayed type IV allergic hypersensitivity or irritation in human subjects.

Abstract  A study has been made of the acetoxylation of 1-hexene and cyclohexene in the presence of PdCl42- and a nitrate-iodate reoxidative system ensuring high yields of the corresponding acetoxyalkanes. It has been established that a binuclear pi-olefinic bridge-type palladium complex is a catalytically active particle. It is assumed that the mechanisms of formation of 1,2-hexanediol monoacetate and diacetoxycyclohexane differ at the final stage of transformation of the acetoxonium ion. Acetoxylation is retarded by the reaction products, which screen the coordination sphere of palladium.

Abstract  Aqueous dilute solutions of 2-butoxyethanol, 1,2-hexanediol, tert-butanol, 1-pentylamine and 1-butylamine are analized through the dynamic light scattering technique. The mutual diffusion coefficient is determined against amphiphile composition, showing, in all cases, clear minima in the dilute region. Using the Stokes-Einstein relation, the mean size of the aggregates is also obtained as a function of mole fraction. For enough concentrated solutions, structures in the range 2-20 angstrom are observed. It is found that both their size and the minimum amphiphile mole fraction for which aggregation is observed are strongly correlated with the hydrophobic character of the amphiphile. (C) 2017 Elsevier B.V. All rights reserved.

Abstract  We report the use of the ionic liquid tetrabutylphosphonium bromide as a solvent and catalyst for dehydration of diols to conjugated dienes. This system combines stability, high reaction rates, and easy product separation. A reaction mechanism for the model compound 1,2-hexanediol is proposed and experimentally corroborated. This particular mechanism allows for the selective formation of conjugated dienes, in contrast with purely acidic catalysis. Next, the reaction is also performed on various other diols. As a first application, we assessed the biobased production of 1,3-butadiene. With 1,4-butanediol as the starting material, a 94% yield of butadiene was reached at 100% conversion.

Abstract  Sorbitol can be selectively transformed into liquid alkanes over a bifunctional catalytic system Pt/ZrO2 + TiO2-WOx. In this paper, we investigated the reaction mechanism by carefully analyzing the numerous products issued from sorbitol and by studying the reactivity of some identified intermediates (1-hexanol 2-hexanol, 2-hexanone, 2,5-dimethyltetrahydrofuran, 1,2-hexanediol and 1,2,6-hexanetriol). This led us to propose that C-C cleavage reactions occur on terminal C-C bonds and mainly consist of dehydrogenation-decarbonylation reactions. The limiting steps of the sorbitol transformation are the isosorbide and mono-oxygenated intermediate transformations, especially the hydrogenation of ketones. It is also assessed that diols or triols with n carbon atoms are mainly converted in compounds with n - 1 carbon atoms. Short compounds (1 to 3 carbon atoms) are obtained via a dehydrogenation-retro-aldol reaction pathway and not from isosorbide conversion. (C) 2014 Elsevier Inc. All rights reserved.

Abstract  Parabens are used as antimicrobial preservatives in consumer products. Exposure to methylparaben (MP) has been associated with adverse health outcomes, therefore, an alternative compound, 1,2-hexanediol (1,2-H), has been applied for cosmetics. In the present study, the phototoxicity of MP and 1,2-H, as well as the toxic effect caused by chronic exposure, were investigated using Daphnia magna. The 48 h acute toxicity tests with D. magna were conducted under indoor or ultraviolet (UV) light irradiation conditions, i.e., exposure to 4 h/d sunlight. Changes in the transcription of genes related to oxidative stress were determined in D. magna juveniles, to investigate the underlying mechanism of phototoxicity. The 21 d chronic toxicity tests of MP and 1,2-H were performed under indoor light irradiation. Exposure to MP under environmental level of UV light was more detrimental to D. magna. Transcripts of catalase and glutathione-S-transferase genes in D. magna was significantly increased by co-exposure to MP and UV light. After 21 d of chronic exposure to MP and 1,2-H, the reproduction no-observed effect concentrations for D. magna were 1 and >10 mg/L, respectively. The present study showed that exposure to UV could magnify the toxicity of MP on daphnids. Although acute and chronic toxicities of 1,2-H were generally lower than those of MP, its effects on other aquatic organisms should not be ignored. Further studies are needed to identify other mechanisms of MP phototoxicity.

Abstract  The objective of the present study is to investigate the effect of hydrocarbon chain length in 1,2-alkanediols on percutaneous absorption of metronidazole (MTZ). Twelve formulations (1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol in 4% concentration, 1,2-hexanediol, and 1,2-heptanediol in 1% concentration, in the absence and presence of 1,4-cyclohexanediol, respectively) were studied in an in vitro hairless mouse skin model using Franz diffusion cell. Based on the flux values and retardation ratios (RR), a penetration retardation effect on percutaneous absorption of MTZ was observed for the formulations containing 1,2-diols having six- to seven-carbon chain in the presence of 1,4-cyclohexanediol (1,2-hexanediol with chain length of six hydrocarbons, RRs are 0.69 and 0.76 in the concentration of 4% and 1%, respectively; 1,2-heptanediol with chain length of seven hydrocarbons, RR is 0.78 in the concentration of 1%). On the other hand, no retardation effect was observed in formulations containing short alkyl chains (RRs of 1,2-propanediol, 1,2-butanediol, and 1,2-pentanediol are 0.99, 1.61, and 0.96, respectively). Instead, a penetration enhancement effect was observed for 1,2-diols having four and five carbons. In other words, effect of 1,2-alkanediols on percutaneous absorption of MTZ can be systematically modulated by simply varying number of -CH2 groups in the hydrocarbon chain-from being a penetration enhancer to retardant. These observations shed light on mechanism of the penetration enhancement and retardation effect and provide insight into rational design of penetration enhancers and retardants. Furthermore, the combination of 1,2-alkanediols and 1,4-cyclohexanediol could become a general vehicle for controlled release of pharmaceutical and cosmetic active ingredients.

Abstract  The ruthenium aqua complexes [cp*Ru(OH2)(N-N)](OTf) (cp* = [small eta]5-pentamethylcyclopentadienyl, N-N = 2,2[prime or minute]-bipyridine, phen = 1,10-phenanthroline, OTf- = trifluoromethanesulfonate) and the acetonitrile complex [cpRu(CH3CN)(bipy)](OTf) (cp = [small eta]5-cyclopentadienyl) are water-, acid-, and thermally stable (200 [degree]C) catalysts for the hydrogenation of aldehydes and ketones in sulfolane solution. In the presence of HOTf as a co-catalyst, they effect the deoxygenation of 1,2-hexanediol to 1-hexanol and hexane. Glycerol is deoxygenated to 1-propanol in up to 18% yield and under more forcing conditions completely deoxygenated to propene. The structure of the acetonitrile pro-catalyst [cpRu(CH3CN)(bipy)](OTf) has been determined by X-ray crystallography (space group P[1 with combining macron] (a = 9.3778(10) A; b = 10.7852(10) A; c = 11.1818(13) A; [small alpha] = 101.718(5)[degree]; [small beta] = 114.717(4)[degree]; [gamma] = 102.712(5)[degree]; R = 3.95%).

Abstract  Two tests for biodegradability, the modified OECD test and the modified Sturm test, were compared by application to 5 organic compounds (aniline, monoethanolamine, pentaerythritol, 1,6-dihydroxyhexane, and 2,4,6-trichlorophenol), using activated sludge from a full scale sewage works as inoculum. In both tests, there was 70 per cent reduction in dissolved organic carbon for all the test compounds. In the modified Sturm test, however, when biodegradability was assessed on the bases of carbon dioxide production, it appeared to be much lower. The discrepancy between the results was attributed to carbon assimilation and was most obvious when a preconditioned innoculum was used. The implication for standardization of tests on biodegradability are indicated.

Abstract  Silicon nanowire possesses great potential as the material for renewable energy harvesting and conversion. The significantly reduced spectral reflectivity of silicon nanowire to visible light makes it even more attractive in solar energy applications. However, the benefit of its use for solar thermal energy harvesting remains to be investigated and has so far not been clearly reported. The purpose of this study is to provide practical information and insight into the performance of silicon nanowires in solar thermal energy conversion systems. Spectral hemispherical reflectivity and transmissivity of the black silicon nanowire array on silicon wafer substrate were measured. It was observed that the reflectivity is lower in the visible range but higher in the infrared range compared to the plain silicon wafer. A drying experiment and a theoretical calculation were carried out to directly evaluate the effects of the trade-off between scattering properties at different wavelengths. It is clearly seen that silicon nanowires can improve the solar thermal energy harnessing. The results showed that a 17.8 % increase in the harvest and utilization of solar thermal energy could be achieved using a silicon nanowire array on silicon substrate as compared to that obtained with a plain silicon wafer.

Abstract  Epoxide hydrolases (EHs) of fungal origin have the ability to catalyze the enantioselective hydrolysis of epoxides to their corresponding diols. However, wild type fungal EHs are limited in substrate range and enantioselectivity. Additionally, the production of fungal epoxide hydrolase (EH) by wild-type strains is typically very low. In the present study, the EH-encoding gene from Rhodotorula araucariae was functionally expressed in Yarrowia lipolytica, under the control of a growth phase inducible hp4d promoter, in a multi-copy expression cassette. The transformation experiments yielded a positive transformant, with a final EH activity of 220 U/g dw in shake-flask cultures. Evaluation of this transformant in batch fermentations resulted in approximately 7-fold improvement in EH activity over the flask scale. Different constant specific feed rates were tested in fed-batch fermentations, resulting in an EH activity of 1,750 U/g dw at a specific feed rate of approximately 0.1 g/g/h, in comparison to enzyme production levels of 0.3 U/g dw for the wild type R. araucariae and 52 U/g dw for an Escherichia coli recombinant strain expressing the same gene. The expression of EH in Y. lipolytica using a multi-copy cassette demonstrates potential for commercial application.

Abstract  1,2-Hexanediol (1,2-HD) and 1,2,3-octanetriol (1,2,3-OT) are known to self-associate in a manner very similar to that of conventional surfactants to give rise to micellelike aggregates (Hajii, S.; et al. J. Phys. Chem. 1989, 93, 4819). This paper reports on fluorescence probing, with pyrene as a probe, of these aggregates and on a study of the kinetics of monomer exchange between aggregates and bulk phase by means of the ultrasonic relaxation method in the frequency range 0.5-100 MHz. Thus the polarity sensed by pyrene solubilized in the aggregates is lower than for conventional nonionic surfactants of the C(n)E(m) type. The critical micellization concentrations determined by fluorescence probing are in agreement with the reported values. The ultrasonic relaxation amplitude A and frequency f(R) have been found to vary with concentration as expected from the expressions derived for conventional surfactants on the basis of the Aniansson and Wall treatment for the kinetics of surfactant exchange. The full use of these expressions permitted us to obtain the values of the rate constants kappa+ kappa-for the incorporation of a surfactant monomer into, and the dissociation of a monomer from, a micelle, respectively, as well as the standard deviation characterizing the distribution of micelle aggregation numbers (polydispersity) and the volume change upon incorporation. These results are discussed and compared to those obtained for conventional surfactants.

Abstract  A series of ruthenium complexes of the general composition [(eta(6) -arene)(N boolean AND N)Ru(X)] (Y)(n), (arene = p-Me-Pr-i-C6H4, C6Me6; N boolean AND N = bipy, phen, 6,6'-diamino-2,2'-bipyridine, 2,9-diamino-1,10-phenanthroline; X=Cl, H, H2O; Y=Cl, OTf) was synthesized and the new compounds exhaustively structurally characterized by standard techniques (NMR, IR, elemental analysis, single-crystal X-ray crystallography). The single-crystal X-ray structures of [(p-Me-Pr-i-C6H4)Ru(dabipy)Cl][CI] (3CI[CI]), [(p-Me-Pr-i-C6H4)Ru(daphen)CI][CI] (4CI[CI]), [(C6Me6)Ru(dabipy)CI][CI] (7CI[CI]), [(C6Me6)Ru(daphen)CI][CI] (8CI[OTf]), [(p-Me-Pr-i-C6H4)Ru(bipy)(H2O)][OTf](2) (1O[OTf](2)), [(p-Me-Pr-i-C6H4)Ru(dabipy)(H2O)][OTf](2) (3O[OTf](2)), [(p-Me-Pr-i-C6H4)Ru(dabipy)(H2O)][SO4] (3O[SO4]), [(P-Me-(PrC6H4)-Pr-i)-Ru(daphen)(H2O)][OTf](2) (4O[OTf](2)), [(C6Me6)Ru(daphen)(MeOH)][OTf](2) (8(MeOH)[OTf](2)), [(p-Me-Pr-i-C6H4)Ru(dabipy)(H)][OTf] (3H[OTf]), [(p-Me-Pr-i-C6H4)Ru(daphen)(H)][OTf] (4H[OTf]), [(C6Me6)Ru(dabipy-BH2-OTf)(H)] (7H[-NH2-BH2-OTf]) have been determined. Under 750-1100 psi (5-7.5 MPa) of hydrogen pressure at 110 degrees C in the presence of acid and water in sulfolane solvent the aquo complexes form active catalysts for the selective deoxygenation of terminal diols, notably 1,2-hexanediol, to the corresponding primary alcohol, i.e., 1-hexanol in up to 60% yield. The presence of amino functions on the ortho-positions of the chelating ligands results in lower catalyst activity. Under the same reaction conditions the catalysts fail to convert glycerol to GC-detectable products. At the higher temperatures (T> 150 degrees C) possibly required for glycerol activation the catalysts show increasing decomposition with increasing temperature. (C) 2007 Elsevier B.V. All rights reserved.

Abstract  The inhibition effect of the surfactants 1,2-hexanediol (HD), 1,2,3-octanetriol (OT); 1,2,3-nonanetriol (NT); and 3,7-dimethyl-1,2,3,6,7-octanepentol (DOP) on the corrosion of iron in 1 M hydrochloric acid (HCl) was studied, Results obtained from gravimetric methods showed inhibition efficiencies increased with increasing surfactant concentrations and attained a maximum around their critical micellar concentration (cmc). A comparative study of corrosion inhibition of surfactants indicated DOP was the best inhibitor, Polarization measurements showed DOP was a cathodic type-inhibitor and acted on the cathodic reaction without modifying the mechanism of the hydrogen evolution reaction. DOP appeared to function through a general adsorption mode following the Langmuir adsorption isotherm The effect of temperature on the corrosion behavior of iron in both 1 M HCl and 1 M HCl with addition of various concentrations of DOP was studied in the temperature range from 18 degrees C to 48 degrees C, The associated activation corrosion and free adsorption energies were determined.

Abstract  The α-proteobacterium Sphingomonas wittichii RW1 is known for its ability to degrade dioxins and related toxic substances. Bioinformatic analysis of the genome indicated that this organism may contain the largest number of pyrroloquinoline quinone-dependent dehydrogenases of any bacteria sequenced so far. Sequence analysis also showed that one of these genes (swit_4395) encodes an enzyme that belongs to the class of periplasmic glucose dehydrogenases. This gene was fused to a pelB signal sequence and a strep-tag coding region at the 5' and 3' ends, respectively. The fusion product was cloned into the broad-host range expression vector pBBR1p264-Streplong and the corresponding protein was heterologously produced in Escherichia coli, purified via Strep-Tactin affinity chromatography, and characterized. The protein Swit_4395 had a subunit mass of 39.3 kDa and formed active homooctamers and homododecamers. The enzyme showed the highest activities with short- and medium-chain aldehydes (chain length C1-C6) and ketoaldehydes, such as methylglyoxal and phenylglyoxal. Butyraldehyde was the best substrate, with V max and apparent K M values of 3,970 U/mg protein and 12.3 mM, respectively. Pyrroloquinoline quinone was detected using UV-Vis spectroscopy and was found to be a prosthetic group of the purified enzyme. Therefore, Swit_4395 was identified as a pyrroloquinoline quinone-dependent aldehyde dehydrogenase. The enzyme could be purified from the native host when the expression vector was introduced into S. wittichii RW1, indicating homologous protein production. Overproduction of Swit_4395 in S. wittichii RW1 dramatically increased the tolerance of the bacterium toward butyraldehyde and thus might contribute to the detoxification of toxic aldehydes.

Abstract  BACKGROUND/AIMS: The research on the treatment of "dry skin syndrome" is hampered by the lack of a suitable animal model. Formerly, we developed a validated guinea pig in vivo model in which the dry skin syndrome persists at least for 1 week. We can, therefore, compare the pharmacological effectiveness of known and potential moisturizers for the treatment of dry skin syndrome. Our aim is to study whether the moisturizing efficiency of humectants depends on the solvents in which they are dissolved.

METHODS: "Dry skin syndrome" was induced on the shaved skin on one side of guinea pigs by daily application of 2% sodium lauryl sulphate in deionized water (SLS) for 3 days. The other shaved side was used as control. After ascertaining skin dryness, that side was treated for 6 days with glycerol or 1,2-hexanediol in different solvents: water, or medium chain triglycerides (MCT) or mixtures of MCT with isopropyl alcohol in different proportions. Measurement of the in vivo moisturizing effect was carried out by a Comeometer CM 825; erythema was measured by a Mexameter MX 16.

RESULTS: Treatments with glycerol (1M) in water reversed the skin dryness shown by both instruments. When dissolving glycerol in MCT, no moisturizing effect was found, probably because glycerol does not dissolve in the oil. No moisturizing effect was found with different combinations of glycerol in the mixtures of MCT and isopropyl alcohol. No moisturizing effect was found using another polyol moisturizer: 1,2 hexanediol (1M) dissolved in MCT oil. Glycerol or 1,2-hexanediol abolished the erythema only when they were dissolved in water alone.

CONCLUSION: Polyol moisturizers such as glycerol or 1,2-hexanediol do not act in the presence of oils against the sodium lauryl sulphate-induced dry skin in our guinea pig model. Since in an oil-in-water (O/W) emulsion, the water evaporates within several minutes, one has to question the ability of moisturizing emulsions to treat dry skin. In such instances, one cannot draw conclusions about the moisturizing efficiency of the preparation merely from the presence of the humectant. One has to study the effect of the finished preparation.

Abstract  A series of novel pentacoordinated germanium(IV) complexes (I) has been prepared by the reaction of germanium dioxide with diols, such as 1,2-propanediol, 1,2-butanediol, 2,3-dimethyl-2,3-butanediol ,1-phenyl-1,2-ethanediol, 1,2-hexanediol, 3,3-dimethyl-1,2-butanediol in an aqueous sodium hydroxide medium. The general molecular formula can be represented as NaGe(OH)L2 where L is the deprotonated diol The reaction of germanium dioxide with catechol in distilled water gives Ge(C6H4O2)2.2H2O (II). Further treatment of this complex (II) with methanol, ethanol or 2-propanol gives hexacoordinated germanium (IV) complexes (III), Ge(C6H4O2)2.2ROH (where R = CH3, C2H5, (CH3)2CH, respectively). These complexes, which have been characterized by elemental analyses, thermogravimetric analyses, infrared, H-1 and C-13 NMR spectral studies, reveal that the pentacoordinated germanium(IV) complexes (I) have a slightly distorted trigonal-bipyramidal geometry. However, the suitable structure of the hexacoordinated complexes (II-III) are octahedral.

Abstract  Strontium phenylphosphonate intercalates with 1,2-diols (from 1,2-ethanediol to 1,2-hexanediol) were synthesized and characterized by X-ray diffraction, thermogravimetry, chemical analysis, and molecular simulation methods. Prepared samples exhibit a very good stability at ambient conditions. Structural arrangement calculated by simulation methods suggested formation of cavities surrounded by six benzene rings. Each cavity contained one molecule of diol and one molecule of water for the 1,2-ethanediol to 1,2-butanediol intercalates. In the case of 1,2-pentanediol two types of cavities alternated: one with diol molecules and another one with two water molecules. In the 1,2-hexanediol intercalate the benzene rings created two types of cavities containing one or two diol molecules, respectively, and this conformational variability led to a more disordered arrangement with respect to the models with shorter alkyl chains. Coordination of the oxygen atoms of the diols to the strontium atoms of the host follows the same pattern for all 1,2-diol intercalates except the 1,2-hexanediol intercalate, where these oxygen atoms can be mutually exchanged at their positions. The calculated basal spacings and structural models are in good agreement with experimental basal spacings obtained from X-ray powder diffraction and with other experimental results.