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Showing papers in "Australian Journal of Chemistry in 1971"


Journal ArticleDOI
TL;DR: In this paper, a series of spin-paired bivalent bipyridyl complexes of iron, ruthenium, and osmium, of the type [M(bipy)3]2+, [mipy]2X2Y2]n+ have been prepared.
Abstract: A series of spin-paired bivalent bipyridyl complexes of iron, ruthenium, and osmium, of the type [M(bipy)3]2+, [M(bipy)2X2]n+, [M(bipy)2XY]n+, [M(bipy)X4]n+, [M(bipy)(X2)2]n+, and [M(bipy)X2Y2]n+ (X and Y include a range of monodentate ligands and X2 a range of bidentate ligands) have been prepared. Their electronic spectra within the range 41000-7000 cm-1 have been recorded. All the complexes show two intraligand transitions which are present in free bipyridyl. The iron and ruthenium complexes have two metal oxidation charge-transfer bands, while the osmium complexes have a more complex charge-transfer pattern. Trends in the positions of the bands have been related to the bonding of the ligands X and Y to the metal ions. It is suggested that the energy of the metal t2 type orbitals relative to the ligand π and π* orbitals is the main factor in determining the intense electronic spectra of these complexes.

193 citations


Journal ArticleDOI
TL;DR: In this article, a distinction is drawn between intrinsic diffuseness, associated with excitation to or perturbation by a (quasi-)continuum and including the electronic relaxation mechanism here proposed, and trivial diffusness due to overcrowding of individually sharp lines.
Abstract: Diffuseness, as seen in the vapour absorption spectra of polyatomic molecules, is related with rapid electronic relaxation (radiationless transitions). The causes common to both are perturbations between electronic states. Line broadening is related to excited state lifetimes through the uncertainty principle. To this end, twelve causes of diffuseness are first listed, and their incidence examined. A distinction is drawn between intrinsic diffuseness, associated with excitation to or perturbation by a (quasi-)continuum and including the electronic relaxation mechanism here proposed, and trivial diffuseness due to overcrowding of individually sharp lines. Trivial diffuseness may be temperature dependent (structureless rotational envelopes; overcrowded sequence bands) or, in very large molecules, temperature independent. I t has been shown that rotational envelopes should contain sharp features in a number of transitions which prove, experimentally, to be diffuse. Because of sequence bands, however, there is for any polyatomic molecule a fairly well-defined critical temperature, calculable from ground state vibrational data, above which the entire electronic spectrum must become structureless. This critical temperature decreases with increasing molecular size and with increasing molecular flexibility, and in conjunction with vapour pressure considerations sets definable limits to the kinds of molecule for which structured spectra can be obtained in the gas phase. But this mechanism is insufficient to explain the frequent occurrence of structureless spectra in small rigid molecules. The literature on medium to high resolution spectra of polyatomic molecules is then reviewed, to establish the generalization that the only transitions with structure (if any) will normally be the first triplet (if observable) and the first singlet, and possibly (for special reasons) Rydberg transitions. This survey is complemented by measurements on the following molecules: pyridine N-oxide, indene, indazole, purine, quinoline, isoquinoline, 1,6-naphthyridine, quinazoline, quinoxaline, 1,4,5- triazanaphthalene, biphenylene, fluorene, acridine, tetramethylcyclobutane-1,3- dione, and all monoalkylbenzenes from ethyl to t-butyl. The proposed generalization is found to have wide validity, though there are one or two undeniable exceptions and a few marginal cases. It is associated with Kasha's rule concerning states capable of emitting radiation, though the correlation between the two is not necessarily one-to- one. Taken together, these rules and the evidence on which they are based leave the electronic relaxation mechanism as the only satisfactory explanation so far offered for the widespread occurrence of diffuse electronic transitions in polyatomics. This matter can also be studied in pure and mixed crystals, if it is assumed, as now seems very probable, that the crystalline matrix induces no line-narrowing. Recent systematic work on line widths in crystal spectra a t 4°K by Hochstrasser and Marzzaccol is in full accord with the viewpoint advanced here.

102 citations


Journal ArticleDOI
TL;DR: In this paper, a base-catalysed Wessely-Moser rearrangement of simple phenols was proposed. But the results were limited to the case of ageratochromen and evodionol methyl ethers.
Abstract: α,α-Dimethylpropargyl ethers of simple phenols are readily prepared in high yields. Thermal rearrangement of them affords 2,2- dimethylchromens, also in high yields. These reactions are used to prepare the natural products, ageratochromen, evodionol methyl ether, lapachenole, seselin, luvangetin, and braylin. A base-catalysed Wessely-Moser rearrangement is reported.

69 citations


Journal ArticleDOI
TL;DR: In this article, the vibrational spectra of crystalline halomercurate salts with anionic stoicheiometries HgX3-,HgX42, Hg2X5-, Hg3X82- (where X = Cl, Br, I) have been studied.
Abstract: The vibrational spectra of crystalline halomercurate salts with anionic stoicheiometries HgX3-, HgX42-, Hg2X5-, Hg3X82- (where X = Cl, Br, I) have been studied. The cations Me4N+, Et4N+, Ph4As+, and pyH+ were used as necessary. The effect of crystalline symmetry and packing on the spectra of both anion and cation are discussed and the spectra are used to deduce the most probable crystalline packing for salts containing the Hg2X5- and Hg3X82- species. The spectra of the cations Me4N+ and Et4N+ are assigned and discussed.

48 citations


Journal ArticleDOI
TL;DR: In this article, the parent halocarbonyls themselves were isolated by evaporation of the reaction solution without the addition of suitable cations to the solutions, and the corresponding anions [Ru(CO)X5]- have been isolated and characterized.
Abstract: Formic acid in the appropriate hydrohalic acid both carbonylates and reduces ruthenium trihalides, but the nature of the products isolated depends upon the identity of the halogen. In the chloro system the first product is the pentachloro-carbonylruthenate(III) ion, [Ru(CO)Cl5]2-, and this is then reduced to the tetra- chlorocarbonylaquoruthenate(II) ion, [Ru(CO)(H2O)Cl4]2-. More prolonged reaction gives [Ru(CO)2Cl4]2- and the ultimate product is [Ru(CO)3Cl3]-. In the bromo system there was no evidence for the formation of an aquo-ruthenium(II) species and the iodo system was even more simple as only [Ru(CO)2I4]2- and [Ru(CO)3I3]- were observed. The direct reaction between carbon monoxide and RuX3 in methanol produces compounds of the type Ru(CO)X3 (X = Cl, Br) and the corresponding anions [Ru(CO)X5]- have been isolated and characterized. In all cases the halocarbonyl anions could be isolated by the addition of suitable cations to the solutions. In most cases the parent halocarbonyls themselves were isolated by evaporation of the reaction solution without the addition of cations.

47 citations


Journal ArticleDOI
TL;DR: In this paper, a 7-O-glucosides and their malonate hemi-ester derivatives have been isolated from red clover and from the Yarloop strain of subterranean clover.
Abstract: Formononetin and biochanin A 7-O-glucosides (1a and 2a) and their malonate hemi-ester derivatives (1b and 2b) have been isolated from red clover and from the Yarloop strain of subterranean clover Structure (2b) is a correction of an earlier structural assignment to this compound Small amounts of the derived methyl esters (1c and 2c) are also present in both clovers Similar derivatives of genistein have been obtained from the Yarloop strain, although only the 7-O-glucoside (3a) has been isolated in pure form Studies on red clover and on nine strains of subterranean clover have demonstrated in all cases that the acidic malonate esters account for the predominant proportion of the glycosides

47 citations


Journal ArticleDOI
TL;DR: In this article, a number of radicals generated in a flow cell from cyclic ethers, such as 1,3-dioxolans, 1, 3-Dioxans, and other cyclic and acyclic substrates, were investigated.
Abstract: E.p.r. spectra have been recorded for a number of radicals generated in a flow cell from cyclic ethers, 1,3-dioxolans, 1,3-dioxans, and other cyclic and acyclic substrates. The cyclic radicals do not undergo detectable fragmentation, but the rearrangement of the radical (9) derived from t-butyl acetate has been observed. The mechanism of acetoxy group migration in radicals is discussed in the light of these results. The spectral data, including, in some cases, values of 13C hyperfine splitting factors, indicate that there is considerable deviation from planarity at the radical, centres of some cyclic species, and this phenomenon is accompanied by a change in sign of α-proton splitting factors. The reducing power of radicals derived from cyclic ethers has been investigated.

45 citations


Journal ArticleDOI
TL;DR: In this paper, the first cyclic sexadentate ligands without the aid of the metal template effect were reported, which are octahedral and presumably have the halide ligands cis to each other.
Abstract: A number of cyclic ligands has been prepared by the high-dilution technique. All these ligands have their donor-atoms linked by ethano bridges. Examples of a non-planar quadridentate and three potential sexadentates were prepared. The cyclic quadridentete, 1-oxa-4,10- dithia-7-azacyclododecane (1), formed neutral complexes of the type [MLX2], where M = Co, X = Cl, Br and M = Ni, X = Cl, which are octahedral and presumably have the halide ligands cis to each other. Two of the cyclic ligands, 1,4,10,13-tetrathia-7,16- diazacyclooctadecane (3) and 1,4,7,10,13,16-hexathiacyolooctadecane (4), are the first reported cyclic sexadentates which form octahedral complexes, and the first examples of cyclic sexadentate ligands prepared without the aid of the metal template effect. Complexes of the type [ML](picrate)2, where M = Co, Ni, were prepared from ligands (3) and (4). A third potential sexadentate, 1,10-dioxa-4,7,13,16- tetrathiaoyolooctadecane (5), did not form complexes when treated with MX2, where M = Co, Ni, Fe, Cu and x = Cl, ClO4.

42 citations


Journal ArticleDOI
TL;DR: In this article, the free energies, enthalpies, and entropies of formation of adducts of pyridine and some copper(II) complexes of 3-substituted β-diketones have been determined by thermometric titration in benzene solution.
Abstract: Free energies, enthalpies, and entropies of formation of adducts of pyridine and some copper(II) complexes of 3-substituted β-diketones have been determined by thermometric titration in benzene solution. The results, which show that adduct stability is determined by the enthalpy, are discussed in terms of the relationships of extrathermodynamics.

41 citations


Journal ArticleDOI
TL;DR: In this article, changes of coordination from four to five or six in the xanthates of nickel, lead, zinc, and cadmium results in a shift towards lower energy of the M-S vibration, a small shift to higher energy of C-S vibrations, and an unexpected large shift to lower frequency of the C-O vibration.
Abstract: Changes of coordination from four to five or six in the xanthates of nickel, lead, zinc, and cadmium result in a shift towards lower energy of the M-S vibration, a small shift to higher energy of the C-S vibration, and an unexpected large shift to lower frequency of the C-O vibration.

38 citations


Journal ArticleDOI
TL;DR: When an aerated aqueous solution of tryptophan at pH 6-9 is irradiated by visible light in the presence of a photosensitizing dye, N?- formylkynurenine is usually a major product, but a similar irradiation in dilute ammonia at pH 8-9 gives mainly 4-(2-amino-2- carboxyethyl)quinazoline, a new amino acid.
Abstract: When an aerated aqueous solution of tryptophan at pH 6-9 is irradiated by visible light in the presence of a photosensitizing dye, N?- formylkynurenine is usually a major product. However, a similar irradiation in dilute ammonia at pH 8-9 gives mainly 4-(2-amino-2- carboxyethyl)quinazoline, a new amino acid; formyl-kynurenine 1s shown not to be an intermediate in the photoreaction. Tryptophan methyl ester and 2-methyltryptophan give photoproducts analogous to those of tryptophan. On the other hand, N-acetyltryptophan and indole-3- propionic acid give the formylkynurenine analogue either in the absence or presence of ammonia, no quinazoline being detected.

Journal ArticleDOI
TL;DR: The five-membered oxide (7) as discussed by the authors is a compound with an ambergris-type odour which has been previously prepared from sclareol (13).
Abstract: Manoyl oxide (1) has been converted into the five-membered oxide (7), a compound with an ambergris-type odour which has been previously prepared from sclareol (13). The route involves the intermediates (14), (15), (17), (10), and (32), and gives an overall yield of 17% from manoyl oxide. The oxide (7) has also been prepared from manoyl oxide in two steps by oxidation with chromium trioxide followed by reduction of the lactone (10) with diborane.

Journal ArticleDOI
TL;DR: In this article, the rate of thermal decomposition of RDX has been investigated in the presence of its decomposition products and free radical traps, and it was concluded that formaldehyde and nitrogen dioxide, presumably encaged in the sample, catalyse the decomposition positively and negatively respectively.
Abstract: The rate of thermal decomposition of RDX has been investigated in the presence of its decomposition products and free radical traps. From the measurements, it is concluded that formaldehyde and nitrogen dioxide, presumably ?encaged? in the sample, catalyse the decomposition of RDX positively and negatively respectively. The non-volatile residue also acts as a positive catalyst. The other products have little or no effect on the rate, and the free radical traps did not reduce the rate.

Journal ArticleDOI
TL;DR: In this paper, photovoltaic measurements were made on vacuum-evaporated tetracene films sandwiched between an aluminium and a gold electrode, and the best power conversion efficiency was better than 10-4%.
Abstract: Photovoltaic measurements were made on vacuum-evaporated tetracene films sandwiched between an aluminium and a gold electrode. For polychromatic illumination in air open-circuit voltages of up to 1.2 V were observed with the gold electrode positive. The best power conversion efficiency was better than 10-4%. Two modes of carrier production were distinguished, the first resulting from photon absorption in the first tetracene singlet-singlet electronic transition, and the second associated with lower energy red light photons. Persistent voltages were also found to be generated in the dark, the magnitudes of both these and the photovoltages being reversibly increased by the presence of air.

Journal ArticleDOI
TL;DR: The halides of rnonocyclopentadienyItitanium(~~~) with the general formula cpTiXz have been prepared by pyrolysis from their tetrahydrofuran complexes (cp TiXz,THF) as mentioned in this paper.
Abstract: The halides of rnonocyclopentadienyItitanium(~~~) with the general formula cpTiXz (where X = C1, Br, and I ; and cp = T-cyclopentadienyl) have been prepared by pyrolysis from their tetrahydrofuran complexes (cpTiXz,THF). The THF com- plexes were prepared from the appropriate cyclopentadienyltitanium(~v) trihalide by reduction in THF. They are believed to be monomers of the form shown below, involving a pseudo-tetrahedral stereochemistry about the central titanium atom:

Journal ArticleDOI
TL;DR: In this paper, the authors attempt an a priori calculation of the rate of a particular reaction, in a treatment in which all quantum states associated with nuclear motion are identified either as reactant states or product states.
Abstract: We attempt an a priori calculation of the rate of a particular reaction, in a treatment in which all quantum states associated with nuclear motion are identified either as reactant states or product states. The validity of this separation is discussed in some detail. It is particularly appropriate for non-adiabatic reactions. Passage between reactant levels presents a standard problem in collision theory; passage from reactant levels to product is treated by procedures already well explored in the theory of radiationless transitions between electronic states. A matrix formalism, which draws on the work of Schlag and others, permits all these processes to be handled conveniently. Calculations are then carried out for the reaction N2O(1Σ+) → N2(1Σ+g) + O(3P) for which experimental data are extensive. The spectroscopic data are incomplete, however, and the product potential surface has still to be defined in terms of adjustable parameters. Practical approximations, needed to handle the thousands of vibrational levels of N2O, are proposed and found to meet a convergence test. The calculations are performed on models with one (NO stretch) and two (NO, NN stretches) degrees of freedom. Even with the neglect of anharmonicity in the ground state, and with other approximations, the computational elaboration involved in including the second degree of freedom is large. Agreement with experimental rates and activation energies can be obtained in both high and low pressure limits with reasonable values of the upper state parameters, though the fit to the intermediate pressure region is apparently no better than that obtained by the simple Lindemann-Hinshelwood approach.

Journal ArticleDOI
TL;DR: In this paper, the relative contributions of different mechanisms for spin-coupling were studied in a series of compounds of formula AI3MIII2X9 (A = univalent cation, M = Cr or Mo, X = Cl or Br) over the range 90-450°K.
Abstract: Magnetic exchange has been studied in a series of compounds of formula AI3MIII2X9 (A = univalent cation, M = Cr or Mo, X = Cl or Br) over the range 90-450°K. By correlating the variations observed with X-ray data on bond angles and metal-metal distances in the M2X93- binuclear entity, information on the relative contributions of the different mechanisms for spin-coupling has been obtained. In the case of the molybdenum compounds direct exchange predominates. Superexchange through the bridging halogens constitutes a minor proportion of the total exchange but the relative contributions of the ferromagnetic and antiferromagnetic superexchange are affected by structural variations. For the corresponding chromium compounds, in which the total exchange is smaller by a factor of 50 or more, superexchange is comparable in magnitude with direct exchange.

Journal ArticleDOI
TL;DR: In this article, the isopropyl group of methyl abieta-8,11,13 trien-18-oate has been functionalized by intramolecular cyclizations of the 12-carboxy derivative with lead tetraacetate and by thermolysis of the diazomethyl ketone.
Abstract: Functionalization of the isopropyl group of methyl abieta-8,11,13- trien-18-oate (8) has been achieved by intramolecular cyclizations of the 12-carboxy derivative (10) with lead tetraacetate and by thermolysis of the diazomethyl ketone (11). Nitration of methyl 12-acetylabieta-8,11,13-trien-18-oate (9) has given the products (21) and (30), arising from nitrodeacylation and nitrodealkylation reactions, respectively. The nitro ketone (30) has been converted into methyl 13-hydroxypodocarpa-8,11,13-trien-18-oate (38) in 26% overall yield from the ester (8). Birch reduction of the methyl ether of the phenol (38) afforded the enone (50), a potentially useful intermediate for synthesis.

Journal ArticleDOI
TL;DR: Muller et al. as discussed by the authors showed that green specimens of the comatulid crinoid, Comanthus parvicirrus timorensis J. Muller, yield to acetone three yellow water-soluble colouring matters, comaparvin sulphate, 6-methoxycomaparanvin sulfate, and 6-methyl ether sulphate in approximately 0.1 %, 0.7 %, and 0.5 % yield respectively of the dry weight of the animal.
Abstract: Green specimens of the comatulid crinoid, Comanthus parvicirrus timorensis J. Muller, yield to acetone three yellow water-soluble colouring matters, comaparvin sulphate, 6-methoxycomaparvin sulphate, and 6-methoxycomaparvin 5-methyl ether sulphate in approximately 0.1 %, 0.7 %, and 0.7 % yield respectively of the dry weight of the animal, Mild acid hydrolysis yields the corresponding phenols, the structures of which have been deduced largely by spectral studies as very probably 5, 8-dihydroxy-10-methoxy-2-n-propyl-4H-naphtho[1, 2-b]pyran-4-one (1), the 6-methoxy derivative of (1), and the 6-methoxy methyl ether of (1) respectively. A yellow colour variant of the same species yielded the same colouring matters in slightly different proportions. The calcareous skeleton contains what are probably polyhydroxynaphthoquinones in combined form.

Journal ArticleDOI
TL;DR: In this paper, the coordination of triphenylarsine oxide to bispentafluorophenylmercury in solution has been detected, but the complex could not be isolated.
Abstract: The complexes (C6F5)2HgL (L = 4,4?-dimethyl-2,2?-bipyridyl, 2,2?- biquinolyl, 2,2?:6?,2?-terpyridyl, 2,4,7,9,-tetramethyl-1,10- phenanthroline, ethylenediamine, o-phenylenediamine, diphenylamine, pyridine, 4-cyanopyridine, triphenylphosphine, triphenylphosphine oxide, or 1,2-bisdiphenylarsinoethane), (C6F5)2HgL2 (L = di-2- pyridylamine), and [(C6F5)2Hg]2L (L = bisdiphenylphosphinomethane or bisdiphenyl-arsinomethane) have been prepared, and their constitution, solution stabilities, and structures studied, together with those of the known complexes (C6F5)2HgL (L = 2,2?- bipyridyl, 1,10-phenanthroline, or 1,2-bisdiphenylphosphinoethane). Coordination of triphenylarsine oxide to bispentafluorophenylmercury in solution has also been detected, but the complex could not be isolated.

Journal ArticleDOI
TL;DR: In this article, an attempted synthesis by thermal decomposition of indium trispentafluorobenzoate was un-successful, and the complex (C6F5)3In,diox (diox = 1,4-dioxan) has been obtained by reaction of Indium trichloride with pentaphluorophenyl-magnesium chloride or with an excess of bispentaphlorophenylmagnesium.
Abstract: Trispentafluorophenylindium has been prepared by heating iodopentafluoro-benzene with an excess of indium metal, but was obtained mixed with iodobispenta-fluorophenylindium when the stoicheiometric amount was used. An attempted synthesis by thermal decomposition of indium trispentafluorobenzoate was un-successful. Reaction of indium with bispentafluorophenylmercury and subsequent treatment with ether gave (C6F5)3In,OEt2. The complex (C6F5)3In,diox (diox = 1,4-dioxan) has been obtained by reaction of indium trichloride with pentafluorophenyl-magnesium chloride or with an excess of bispentafluorophenylmagnesium, and C6F5InCl2,diox from bispentafluorophenylmagnesium and an excess of indium trichloride.

Journal ArticleDOI
TL;DR: In this article, the authors have calculated the excess free energy of mixing aqueous NaCl with a quaternions hare for various ionic strengths, and the results have been compared with those previously obtained at 25°.
Abstract: Isopiestic vapour pressure measurements have been made on the systems H2O-NaCl-Na2SO4 and H2O-NaCl-MgSO4 at 15° and 0°. Excess free energies of mixing the aqueous salts hare been calculated for various ionic strengths, and the results have been compared with those previously obtained at 25°. Within experimental uncertainty the excess free energies of mixing of aqueous NaCl with aqueous Na2SO4 are the same at 0°, 15°, and 25°. However, the excess free energy of mixing aqueous NaCl with aqueous MgSO4 shows differences which may be just larger than experimental uncertainty over the same temperature range.


Journal ArticleDOI
TL;DR: The configuration of several alkylidenephthalimidines, formed by dehydration of 3-alkyl-3-hydroxyphthalimidine, has been established by nuclear magnetic resonance techniques as discussed by the authors.
Abstract: The configuration of several alkylidenephthalimidines, formed by dehydration of 3-alkyl-3-hydroxyphthalimidines, has been established by nuclear magnetic resonance techniques. When the nitrogen substituent is alkyl or aryl the configuration is (E) but when hydrogen it is (Z). Isomerization was observed in the temperature range 60-140°.

Journal ArticleDOI
TL;DR: In this article, the role of bridging in building up the compounds is discussed in terms of observed n.q.r. data for bridging chlorines, and it is shown that many of the complex chlorides of mercury are built up by the joining of octahedral HgCl6 units.
Abstract: Chlorine nuclear quadrupole resonance frequencies are reported for solid compounds of known structure containing linear molecules HgCl2 and Hg2Cl2, approximately trigonal HgCl3-, and a variety of distorted octahedral forms including NH4HgCl3, CsHgCl3, and K2HgCl4,H2O. Compounds of unknown structure of the type (cation+)HgCl3, (cation+)2HgCl4, (cation+)Hg2Cl5, (cation+)2Hg9Cl20, and (cation+)4HgCl6 have also been studied. There are clear correlations between observed n.q.r. frequencies and Hg-Cl infrared stretching frequencies and bond distances. These correlations show the dependence of the degree of covalent bonding in the Hg-Cl bond with distance. The n.q.r. data confirm that many of the complex chlorides of mercury are built up by the joining of octahedral HgCl6 units, distorted in such a way as to preserve to varying extents the identity of the HgCl2 molecule. Predictions of the structures are made for some complex chlorides of unknown structure, and the role of bridging in building up the compounds is discussed in terms of observed n.q.r. data for bridging chlorines.

Journal ArticleDOI
TL;DR: The reactions of pyridine with bis(ethylxanthato)nickel(~~) and bis(dipropy 1-dithiophosphato)-nickel (~~) were studied by thermometric titration in benzene solution a t 30°C as discussed by the authors.
Abstract: The reactions of pyridine with bis(ethylxanthato)nickel(~~) and bis(dipropy1- dithiophosphato)nickel(~~) and of pyridine, 4-methylpyridine, bipyridyl, and 2,9-dimethyl-l,l0-phenanthroline with bis(diethyldithiophosphato)nickel(~~) have been studied by thermometric titration in benzene solution a t 30°C. The xanthate adds two molecules of pyridine simultaneously, AHolz = -75 kJ mol-1, ASOlz = -186 J K-1 mol-1. With the dithiophosphates, two molecules of base are added in distinct steps; the enthalpy of addition of bipyridyl is similar to that of two molecules of pyridine, but the enthalpy of addition of 2,9-dimethyl-l,l0- phenanthroline is much smaller. The thermodynamic data obtained for these reactions are as follows (AH" in k J mol-1, AS0 in J K-1 mol-1) : dipropyldithiophosphate with py AHol -71, AS01 -211, AHoz 4-2, AS0$ +34 diethyldithiophosphate PY -73 -218 +4 + 40 diethyldithiophosphate 4-mepy - 83 -248 + 7 + 59 diethyldithiophosphate bipy -76 diethyldithiophosphate Mesphen -47 Determination of the magnetic susceptibility in benzene solution containing varying pyridine concentrations has shown that base adducts of the dithiophosphates of both the types NiLzB and NiLzBz have the metal atom in the high-spin configuration.

Journal ArticleDOI
TL;DR: In this paper, the capsular mucilage of the seeds has been extracted in 7% yield and the mucilage is composed of D-glucose, D-galactose and D-mannuronic acids in the approximate ratio 8 : 5 : 2 : 1 : 1: 1 : 2 and uronic acids (8.15%).
Abstract: The capsular mucilage of the seeds has been extracted in 7% yield. It is partly O-acetylated (OAc, 4.0%) and contains lipids (?free? 24% and ?bound? 5%). The mucilage is composed of D-glucose, D-galactose, D- mannose, L-arabinose, D-xylose, and L-rhamnose in the approximate ratio 8 : 5 : 2 : 1 : 1 : 2 and uronic acids (8.15%). The uronic acids were identified as D-galacturonic and D-mannuronic acids. The mucilage was fractionated into an acid-soluble fraction, which was significantly acetylated (OAc, 6.6%) and rich in uronic acids (34.4%) and pentosans, and an acid- insoluble fraction rich in hexosans. The latter on further fractionation with alkali gave a glucomannan with glucose and mannose in the ratio 10 : 3, end a galacto-glucomannan with galactose, glucose, and mannose in the ratio 2 : 4 : 1. Thus the mucilage is heterogeneous, containing at least three different polysaccharides, and is comparable to cellulose-containing seed mucilages and acidic bacterial polysaccharides.

Journal ArticleDOI
TL;DR: In this paper, the excess volumes of binary mixtures of ten organic liquids with water have been measured at a pressure of 1013 bar (1000 atm) at 30°C.
Abstract: The compressions of binary mixtures of ten organic liquids with water have been measured at a pressure of 1013 bar (1000 atm) at 30°C. The excess compressions for these and six similar systems are compared and used to derive the excess volumes, under pressure, of fourteen of the systems. In all cases the excess volumes are numerically smaller at 1013 bar than at 1 bar and, in this sense, the solutions are more nearly ideal. For the ethanol-water system, the excess volumes at the two pressures are compared with theoretical values derived from the dipole model of Haskell. There is qualitative agreement, although it may be fortuitous.

Journal ArticleDOI
TL;DR: In this article, the experimental results on the velocity of sound, densities, and heat capacities of eight organic liquids at 25°, 35°, and 45°C were presented.
Abstract: This paper presents the experimental results on the velocity of sound, densities, and heat capacities of eight organic liquids at 25°, 35°, and 45°C. Using Eyring's equation, the free volumes have been calculated from the sound velocity data. For pure liquids, a quantity Cv* = (Cv)L- (Cv)g- Cstr called the residual heat capacity is found to be linearly dependent on free volume. Analysis of the data for 34 liquids shows that a plot of residual heat capacity against the free volume gives a series of straight lines differing in slopes for different groups of liquids such as hydrocarbons, halogen-substituted hydrocarbons, alcohols, etc. This behaviour is ascribed as being due to different degrees of rotational freedom of molecules in these liquids.

Journal ArticleDOI
TL;DR: In this article, the spin density on the ligand has been calculated by the INDO method on nickel(II) complexes of quinoline N-oxides, water, ammonia, aliphatic amines, aromatic nitriles, and isonitriles as well as on the acetylacetonates of a variety of metals.
Abstract: Calculations of spin density on the ligand have been made by the INDO method on nickel(II) complexes of quinoline N-oxides, water, ammonia, aliphatic amines, aromatic nitriles, and isonitriles as well as on the acetylacetonates of a variety of metals. Three cases are distinguished: (1) the ligand could be considered purely as a cation or anion; (2) the ligand could be considered as a hybrid of cation and anion; (3) neither of these approaches is satisfactory, indicating that neglect of metal orbitals causes serious errors.