bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetism and structure of a novel trinuclear cluster compound of divalent copper
Authors: Beckett R , Colton R , Hoskins BF , Martin RL , Vince DG
Published: September 2010

The magnetic properties of
a series of salts of the type [Cu3L3OH]2+
(where HL is pyridine-2-aldehyde oxime and L is the deprotonated ligand) have
been examined. All of the compounds showed a magnetic moment of 1.00 B.M. per
copper atom over a wide temperature range which suggests that the cation
contains a trinuclear cluster of interacting copper atoms. The crystal structure of Cu3L3OH(SO4),xH2O
has been determined by single- crystal X-ray diffraction techniques and
confirms that the complex does indeed contain an unusual type of trinuclear
cluster of metal atoms. The three copper atoms form an equilateral triangle and
the sulphato group exhibits a highly novel ?tripod? bridging function to the Cu3
triangle. On the other side of the triangle, the hydroxyl group also bridges to
all the metal atoms. A qualitative molecular orbital analysis not only suggests
that the hydroxyl group is involved in four-centre bonding with the Cu3
triads, but also highlights its role in reducing the spin of the trimer so that
only a doublet ground state is populated between 80-300�K. However, the alternative
super-exchange mechanism cannot be ruled out by the magnetic and structural
data.
Flavan derivatives. XXVII. Synthesis of a new racemate of leucocyanidin tetramethyl ether (2,3-cis-3,4-trans-isomer); N.M.R. spectra of the four racemates of leucocyanidin tetramethyl ether (5,7,3',4'-Tetramethoxyflavan-3,4-diol)
Authors: Baig MI , Clark-Lewis JW , Thompson MJ
Published: September 2010

The previously unknown 2,3-cis-3,4-trans
racemate of 5,7,3?,4?- tetramethoxy-flavan-3,4-diol has been prepared by
indirect epimerization of the 4-hydroxyl group in the cis-cis-diol. Tabulated
N.M.R. data for the four possible racemic leucocyanidin tetramethyl ethers (and
their diacetates) provide the basis for unequivocal assignment of configuration
to the methyl ethers of naturally occurring monomeric flavan-3,4-diol
leucocyanidins. The n.m.r, data are presented to assist in clarification of the
structures of these natural products; this clarification is especially
desirable because more than the theoretically possible number of dextrorotatory
5,7,3?,4?- tetramethoxyflavan-3,4-diols have already
been reported.
Magnetism, electronic spectra, and structure of transition metal alkoxides. IX. Vanadium(III)chloromethoxides
Authors: Kakos GA , Winter G
Published: September 2010

The compounds VCl(Ome2 (1), VCl(OMe)2,MeCOMe (2), VCl(OMe)2,MeOH
(3), and VCl2(OMe),2MeOH (4) were prepared. From magnetic and other physical measurements it is
concluded that in (1) the vanadium atoms form trimeric
clusters which associate through chlorine bridges to form an infinite lattice.
Similar basic units are proposed for (2), but separated from each other by
solvent molecules. Two forms of (3) were isolated from the same solution; a
soluble trimeric form (A) for which a structure
similar to that of (2) is suggested, and an insoluble tetrameric
form (B) where the vanadium atoms are situated at the corners of a rhombus. For
(4) a structure involving three octahedra, sharing
corners (methoxy bridges), is suggested.
Pulse studies in nuclear quadrupole resonance spectroscopy
Authors: Doolan KR , Hacobian S
Published: September 2010

Results from both pulsed
and sinusoidal quenching for 35Cl nuclear
quadrupole resonances are reported here for polycrystalline samples of sodium ohlorate and p-dichlorobenzene at room temperature and at
liquid air temperature. Multiple and single maxima were obtained on the curves
of nuclear signal plotted against sinusoidal quench frequency and are explained
by analysis of the quenching signal spectral distribution, together with the
behaviour of the radiofrequency magnetic field amplitude within the sample
coil. From the results obtained a value for the apparent spin-spin relaxation
time for p-diohlorobenzene is calculated.
Hemi-alkoxides from reactions of trimethylaluminium with aldehydes or ketones
Authors: Jeffery EA , Mole T
Published: September 2010

One mole of an aldehyde or
ketone reacts stoicheiometrically with one mole of
trimethylaluminium dimer at ambient temperature in hydrocarbon solvents to form
a "hemi-alkoxide" in which an alkoxy group
and a methyl group bridge two aluminium atoms. Benzaldehyde, acetone, acetophenone, benzophenone, and
cyclohexanone give p-alkoxy-p-methyl-tetramethyldialuminiums
(Me2A1.OR.Me.AlMe2; R = CHPhMe, But, CphMea2
CPh2Me, and 1-methylcyclohexyl,
respectively). Such compounds can also be prepared in low yields starting from
alcohols, rather than aldehydes or ketones. The analogous compound, NezAl.N=CPhMe.Me.AlMez, is formed
by reaction of benzonitrile with one mole of
trimethylaluminium dimer in the absence of solvent at 100�. Exchange of methyl groups
between bridge and terminal sites in these new compounds has been studied by
proton magnetic resonance spectroscopy.
Conductances of potassium chloride and tetrabutyl ammonium picrate in dioxan-water mixtures at pressures up to 2500 bars
Authors: Pearce PJ , Strauss W
Published: September 2010

The electrolytic
conductance of solutions of potassium chloride and tetrabutyl-
ammonium picrate over a range of concentrations have been measured in dioxan-water mixtures containing 0, 25, 50, 70, and 80% dioxan at 25� and pressures up to 1000 and 2500 bars
respectively for the two solutes. The solvent concentration range corresponds
to a range of dielectric constants of 78.3 (for water) to 11.98 (80% dioxan). The association of KCl in solutions of low
dielectric constant is reduced by increasing pressure, so that the conductances of the solutions of finite concentration are
not reduced as much by pressure as at infinite dilution. In contrast to this,
the solutions of the tetrabutylammonium picrate are
wholly dissociated even in very low dielectric constant solvents, as is shown
by the limited concentration dependence of the conductance pressure
characteristics.
Stereochemical studies. I. Dehydration of 2,2-dimethylcyclohexanols
Authors: Delaney RM , Middleton S , Norfolk WF
Published: September 2010

The stereoisomeric
4-t-butyl-2,2-dimethylcyclohexanols undergo different essentially
stereospecific reactions with phosphoric acid to give different types of
dehydration products. The possible significance of these results with respect
to the dehydration of 2,2-dimethylcyclohexanol itself and with respect to the
solvolysis of the 4-t-butyl-2,2-dimethyloyolohexyl tosylates is discussed.
Colouring matters of Australian plants. XIV. A naphthoquinone from Lomandra hastilis
Authors: Cooke RG , Robinson JB , Cannon JR , Retallack RW
Published: September 2010

A new natural naphthoquinone, lomandrone, has
been isolated from Lomandra hastilis.
Spectrometric analyses of this compound and its derivatives indicate the
structure 2-ethyl-8-hydroxy-3,6,7-trimethoxy-1,4-naphthoquinone
An alternative structure has been eliminated by synthesis of 6-ethyl-5-hydroxy-2,3,7-trimethoxy-1,4-naphthoquinone.
Carbonyl halides of the Group VI transition metals. XX. Substituted dialkyldithiocarbamato complexes of molybdenum halocarbonyls and their oxidation
Authors: Colton R , Rose GG
Published: September 2010

Complexes of the type
Mo(CO)2RPh3(dtc)2 (R
= P, As, Sb; dtc = dialkyldithiocarbamato)
have been prepared by the interaction of sodium dialkyldithiocarbamates
with, for example, dichlorobis(triphenylphosphine)trioarbonylmolybdenum(11). In solution the complexes
are susceptible to oxidation, but the product obtained depends strongly
upon the nature of the solvent used. In acetone solution oxidation yields
complexes of the type No2O3(dtc)4;
this reaction is very similar to that reported previously for the oxidation of
the parent compounds Mo(CO)3(dtc)2 and Mo(CO)2(dtc)2.
However, oxidation of Mo(CO)2RPh3(dtc)2
in carbon tetrachloride-benzene mixture gives molybdenum(VI) derivatives of
empirical formulae MoO2(dtc)2.
The properties of these compounds are different from those reported by Moore and Larson for other
compounds of the same formula. Infrared and mass spectrometric studies have
shown that our complexes are dimeric and it has been confirmed that those of
Moore and Larson are monomeric.
The diffusion thermoeffect (Dufour effect) in gaseous mixtures of hydrogen and carbon dioxide
Authors: Sawford BL , Spurling TH , Thurley DS
Published: September 2010

Measurements of the diffusion thermo-effect as a function of
pressure and the initial composition of diffusing mixtures are reported for
hydrogen and carbon dioxide at room temperature. Temperature-time curves have been obtained
with the thermometer at six positions above and below the diffusion interface.
A solution the two coupled differential equations derived from the phenomenologioal description of the effect (excluding all
cross terms containing temperature gradients)

shown to agree well with the experimental curves. The agreement is
best when the thermometer is not too close to the diffusion interface and the
initial concentrations the diffusing mixtures are nearly equal.
Colour centres in zircon containing both Eu3+ and U4+ ions
Authors: Fielding PE
Published: September 2010

Single crystals of zircon
containing both Eu3+ and U4+
were grown from flux melts cooled at rates varying between 4�/hr and 2�/hr.
Irradiation with u.v. develops colour
centres only in those regions of a crystal containing Eu3+
and U4+. Fluorescence and absorption spectra measured at
temperatures down to 77�K show that these centres are similar in behaviour to F
and F' centres in the alkali halides. They are thought to be related to an
exchange coupled pair, U4+-02-Eu3+,
but the experimental data permit only a description in terms of one-electron
energy levels. The same basic behaviour is observed for zircon containing U4+
and any other lanthanide but some interesting differences are described
for U4+, Dy3+.
The electrical conductance of the molten salt systems PbCl2 + NaCl, PbCl2 + RbCl, and PbCl2 + CsCl
Authors: Bloom H , Macky CJ
Published: September 2010

The specific conductances of molten mixtures of PbC12+MCl
(M = Na, Rb, Cs) have been measured as
functions of composition and temperatures from 800�C (or in some cases 850�C)
to within a few degrees of the liquidus. The system PbCl2+CsCl exhibits a pronounced maximum of
activation energy for conductance at
0.67 mole fraction CsCl. Equivalent conductances
of the systems have been calculated and have been plotted against atomic
ratio of Pb/Cl. An attempt has been made to explain
the conductance results on the basis of the transport theory of Adam and Gibbs.
The results are best explained by the presence in the PbCl2+RbCl
and PbCl2+CsCl systems of complex ions of
formula PbCl42-.
Pyridyl enamines and dienamines as models of mycobacterial pigments
Authors: Renwick GM
Published: September 2010

N,N'-Tetramethylformamidinium
perchlorate and its higher vinylogue react with 4-picolylsodium to yield 4-(2-dimethylaminovinyl)pyridine
(1) and l-dimethyl-amino-4-(4-pyridyl)buta-1,3-diene (3), and with 2-picolylsodium
to yield the 2-pyridine isomers (2) and (4). The N.M.R. spectra and
dissociation constants of these products are reported. The electronic spectra
of the bases, their mono- and di-cations, and of some
related compounds are described, and comparisons are drawn with coloured alkaloids which are produced by Mycobacterium tuberculosis in the presence of isonicotinoylhydrazide.
Corrigenda - Complexes of binucleating ligands. III. Novel complexes of a macrocyclic binucleating ligand
Authors: Pilkington NH , Robson R
Published: September 2010

By reaction of 5-methylisophthalaldehyde with 1,3-diaminopropane in the presence of various metal salts the following complexes have been isolated: MCu2Cl2,6H2O, MCu2(ClO4)2,2H2O, MCu2(HSO4)2,H2O, MNi2Cl2,2H2O, MCo2Cl2,2CH3OH, MFezCl2,2CH3OH, MMn2Cl2,2H2O, MZn2Cl2,2H2O, (MH2)Ni(ClO4)2,2H2O where MH2 represents the macrocyclic tetrakis-Schiff base obtained by condensation of two molecules each of the diamine and dialdehyde components and M represents the derived dianion which behaves as a novel macrocyclic binucleating ligand. On the basis of magnetic and spectral evidence the complexes are assigned binuclear structures in which the cations are in an approximately square-pyramidal environment. These structural features have been confirmed in the case of MCu2Cl2,6H2O by an independently conducted X-ray crystallographic analysis. It is suggested that (MH2)Ni(ClO4)2,H2O is closely related to the others in that the nickel environment is square-pyramidal and that essentially the same organic ligand framework is present, with two protons rather than a metal ion occupying the second cavity of M.
Polysaccharides of tropical pasture herbage. II. A xylan from the leaf of spear grass (Heteropogon contortus)
Authors: Blake JD , Richards GN
Published: September 2010

Alkaline extraction of spear grass holocellulose gave a xylan which was purified by fractional precipitation as a copper complex. Acid hydrolysis yielded L-arabinose, D-xylose, and an aldobiouronic acid consisting of D-xylose and 4-O-methyl-D-glucuronic acid. Hydrolysis of the methylated xylan gave 2,3,5-tri-O-methyl-L- arabinose, 2,3,4-tri-, 2,3-di-, and 2-O-methyl-D-xylose, and 3-O-methyl-2-O-(2,3,4-tri-O-methyl-D-glucopyranosyluronic acid)-D-xylose. The conditions for isolation of the methylated sugars for gas chromatography were investigated with particular reference to difficulties arising from volatility of the tri-O-methyl pentoses. The xylan is composed of chains of 1,4-linked �-D-xylopyranose residues to which are attached single units of L-arabinofuranose at position 3 and 4-O-methyl-D-glucuronic acid at position 2 of the basal residues.
Solvolysis of sulphonyl halides. V. Hydrolysis and deuterolysis of methanesulphonyl chloride
Authors: Tonnet ML , Hambly AN
Published: September 2010

The values of the thermodynamic parameters of activation have been determined for the solvolysis of methanesulphonyl chloride in H2O and D2O and their mixtures with moderate amounts of dioxan. Some of the data are not in agreement with the postulate that the kinetic solvent isotope effect and the maximum in the rate of solvolysis produced by the addition of dioxan are due to changes in the initial state of the reacting system rather than to changes in the transition state. The addition of dioxan does not produce a large reduction in the solvent isotope effect as reported for the hydrolysis of t-butyl chloride and predicted to be general. The relative rates of solvolysis in mixtures of H2O and D2O are not in agreement with the analysis of such reactions by Swain and Thornton.
Bisquaternary ammonium salts derived from 3α,12α-Diamino-5β-cholane and 3α,12α-Diamino-24-nor-5β-cholane
Authors: Ahmed S , Alauddin M , Caddy B , Martin-Smith M , Sidwell WTL , Watson TR
Published: September 2010

The preparation of 3α,12α-bisdimethylamino-5β-cholane
dimethiodide, 3α,12α-bisdimethylamino-5β-cholane
dimethiodide, 3α,12α- bisdimethylamino-24-nor-5β-cholanedimethiodide,
and 3α,12α- bisdimethylamino-24-nor-5β-cholanediethiodide,
from deoxycholic acid are described. During this work it was found that
attempted copper- quinoline decarboxylation of dehydrocholic acid gives rise to
lactol formation, and that what had previously been considered to be 3α,12α- dihydroxy-5β-cholane is a mixture of
this compound and 12α,24- dihydroxy-5β-cholane. Comparable
selectivity of attack by methanesulphonyl chloride and toluene-p-sulphonyl
chloride occurs with various polyhydric alcohols derived from bile acids, as
evidenced from the products of reduction of the sulphonates with lithium
aluminium hydride. With both 5α- and 5β-cholane derivatives, a C 3
equatorial hydroxyl group exhibits comparable reactivity to the terminal
primary hydroxyl group, generated from the bile acid carboxylic group, towards
both sulphonyl chlorides. With axial hydroxyl groups at C 7 and C 12,
toluene-p-sulphonate formation is much more difficult than methane- sulphonate
formation. Reduction by means of lithium aluminium hydride of equatorial
sulphonate esters at C 7 and C 12 gives rise to a methylene group, but the axial
sulphonates under the same conditions give the axial alcohol. The same clear
distinction between equatorial and axial sulphonate esters is not observed at C
3 and C 6, but 17α- methanesulphonyloxy-5α-androstane
gives 5α-androstane and the 17β- ester gives 17β-hydroxy-5α-androstane.
Reduction of 12-oximino groups in both 5α- and
5β-cholanes with sodium and ethanol, hydrogen in
the presence of a catalyst, or lithium aluminium hydride gives solely the
12α-amino compound.
Aza-analogues of pteridine. III. Some monomethoxy-1,2,4,6,8-pentaazanaphthalenes and related compounds
Authors: Brown DJ , Sugimoto T
Published: September 2010

4-Hydrazino-2-methoxy-6-methyl-5-nitropyrimidine
reacted with triethyl orthoformate to give the ethoxymethylenehydrazino
analogue or 4-methoxy-6-methyl-7-nitro-1,2,3a,5-tetraazaindene according to
conditions. The first of these products was converted by reductive cyclization
and subsequent dehydrogenation into 7-methoxy-5-methyl- 1,2,4,6,8-pentaazanaphthalene. Attempts to hydrolyse this and related
compounds to the corresponding 7-hydroxypentaazanaphthalenes
failed and direct approaches via appropriate 2-hydroxypyrimidines
gave only 4- hydroxy-7-nitrotetraazaindenes. ��� 5-Alkoxypentaazanaphthalenes
were prepared via 1,2-dihydropentaaza- naphthalene or
its 5-chloro derivative. Nucleophilic displacements were used to make the
5-hydroxy, 5-methylthio, 5-diethylamino, and other analogues from 5-methoxy-3-methylpentaazanaphthalene. ��� The ionization constants, ultraviolet
spectra, and proton magnetic resonance spectra of members of both bicyclic
series are tabulated and discussed.
Nucleophilic substitution reactions of 4-t-Butyl-1-methylcyclohexanols
Authors: Beeby PJ , Sternhell S
Published: September 2010

The stereochemistry of the
reaction of a number of nucleophiles with 4- t-butyl-1-methylcyclohexanol
in the presence of acetic and sulphuric acids was studied. The
stereoselectivity of the reaction found to depend on the size of the attacking
nucleophile. Further evidence is presented for the existence of carbonium ion
intermediates in the Ritter reaction. ��� In the series of 1-X-1-methyl-4-t-butyl
derivatives with X = aryl, NHCOR, -CO-, NO2, and NCl2
the equatorial protons at C 2 and C 6 are markedly deshielded in the isomers
where X is axial.
Carbonyl halides of the Group VIII transition metals. V. Halocarbonyl derivatives of ruthenium(III) and ruthenium(II)
Authors: Colton R , Farthing RH
Published: September 2010

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.
Chemistry of the Podocarpaceae. XXXII. Stereochemistry of 6-Bromo-7-oxo derivatives of ring-c aromatic diterpenoids
Authors: Cambie RC , Crump DR , Denny WA , Fullerton TJ
Published: September 2010

The stereochemistry of
6-bromo-7-oxo derivatives of diterpenoids possessing
an aromatic ring c is discussed. Nan-stereospecific bromination of 7-oxo diterpenoids occurs for compounds with an unactivated
aromatic ring provided that no methoxycarbonyl substituent is at C 4. It also
occurs for a C 19 acetate providing an activating substituent is present at C
12, but not for compounds with a C 4 methoxycarbonyl group even if they possess
a C 12 activating substituent. The assignment of configuration of 6-bromo
substituents from nuclear magnetic resonance and nuclear Overhauser effect data
is examined and limitations to the use of optical rotatory dispersion curves
are discussed.
Clathrates of nickel(II) ethylxanthate adducts
Authors: Kruger AG , Winter G
Published: September 2010

Two polymorphic forms of
the adduct of 4,4?-bipyridyl with nickel(II) ethyl- xanthate were isolated, one
of which is capable of trapping a molecule of benzene, diethyl ether, acetone,
chloroform, carbon tetrachloride, or cyclopentadiene. The adduct of 1,10-phenanthroline
with nickel(II) ethylxanthate forms 1:1 compounds with benzene, toluene,
chloroform, and chlorobenzene.
The reaction of hydrazones with chlorine and bromine
Authors: Pross A , Sternhell S
Published: September 2010

The reactions of six
hydrazones with bromine in the presence of pyridine, and of two hydrazones with
chlorine under a variety of conditions, were investigated. Geminal dihalides,
haloalkenes, rearranged products, azines, and carbonyl compounds account for up
to 85% of the products of the reaction with bromine, but the reactions with
chlorine give rise to more complex mixtures. The mechanisms of these reactions
are discussed and compared with the analogous reactions with iodine. The
differences in the distribution of products for different halogens and bases
can be rationalized in terms of competing a-eliminations and nucleophilic
substitutions of common intermediate X-halogeno compounds. However, the
reaction with chlorine is not entirely straightforward. Further evidence is
presented for the intermediacy of halocarbonium ions in the reactions of
hydrazones with halogens in the presence of bases.
Thermodynamics of metal-ligand bond formation. I. Pyridine adducts of copper(II) complexes of 3-substituted β-diketones
Authors: Graddon DP , Heng KB
Published: September 2010

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.
Luminescence and photochemistry of transition metal complexes. I. Studies of temperature dependence of tervalent chromium complexes with oxygen-, nitrogen-, and carbon-coordinated ligands
Authors: Laver JL , Smith PW
Published: September 2010

Experimental investigations
of the luminescence exhibited by a range of tervalent chromium complexes are
reported. The effects of the coordinated ligand on the temperature dependence
of phosphorescence are examined and rationalized in terms of the 4T2-2E
energy interval. In the case of hexaureachromium complexes which emit both
phosphorescence and fluorescence the varying emission intensities observed for
compounds with a variety of anions are interpreted in terms of competition
between the non-radiative thermal repopulation process 2E ~~→ 4T2
and the radiative processes 2E → 4A2, 4T2
→ 4A2.
The gas-phase reaction of methyl acetate and hydrogen bromide
Authors: Daly NJ , Gilligan MF
Published: September 2010

In the gas phase methyl
acetate reacts with hydrogen bromide over the range 419-497� to give methyl
bromide, carbon monoxide, and methanol. Rate constants first order in both
ester and hydrogen bromide are calculated from initial slopes, and are
described by the equation

�������������������� k2 = 1012.29exp(-32312/RT)
ml mol-1 s-1

Kinetic data depart from
this second-order form at early stages of the reaction. The addition of methanol
can reduce the value of k2 to zero. A mechanism involving the
reversible step :

������������������������ CH3COOCH3+HBr
↔ CH3OH+A*

is proposed. The
intermediate reacts with isobutene to form mesityl oxide, and is considered
identical with that formed in the reaction of acetic acid with hydrogen
bromide.
Long-range proton-fluorine spin-spin coupling and 19F substituent chemical shifts (SCS) in the naphthalene ring system
Authors: Adcock W , Matthews DG , Rizvi SQA
Published: September 2010

A number of
acetyl-substituted fluoronaphthalenes have been synthesized and their fluorine
as well as proton N.M.R. spectra have been measured. The methyl proton
resonances of these derivatives appeared as a doublet which indicated long-range
coupling with the fluorine. It was observed that the coupling (JMe,F)
for 3-acetyl-2-fluoronaphthalene and o- fluoroacetophenone is independent of
the magnitude of the 19F substituent chemical shifts (scs) which are
shown to be sensitive indices of the bond-order differences in naphthalene (C 1
and C 2; C 2 and C 3) and benzene. Furthermore, the magnitude of the long-range
proton-fluorine spin-spin coupling constants are solvent dependent. The data
are clearly in accord with a predominant contribution of a ?direct? mechanism
to the proton-fluorine spin-spin coupling.
A model for the thermal regeneration of ion-exchange resins, Part I
Authors: Hamann SD
Published: September 2010

A theoretical model has
been developed to describe the thermal regeneration of ion-exchange resins in
the Sirotherm process1-10
for desalting water. It assumes that the thermal effect is primarily due to the
large increase that occurs in the ionization of water when the temperature is
raised. The hydrogen and hydroxyl ions compete with salt for exchange sites in
the resins and for that reason water, itself, acts as a regenerating acid and
base. ��� Calculations have been made of the
equilibrium conditions, column behaviour, and titration behaviour of mixtures
of weak-acid and weak-base resins with aqueous solutions of 1 : 1 and 2 : 2
electrolytes, assuming the systems to obey Donnan's
equilibrium relationship. There is satisfactory agreement between the calculated
and observed effects of both temperature and pressure.
Reactions of primulagenin A. II. Acid-catalysed transformation
Authors: Hensens OD , Lewis KG
Published: September 2010

Treatment of primulagenin A
with methanolic hydrochloric acid gave a complex mixture of products from which
the known aegiceradiol (oleana- 12,15-diene-3β,28-dial) and aegiceradienol
(28-noroleana-12,17(18)- dien-3β-ol) were
obtained. In addition, three new products, a double- bond isomer of
aegiceradiol, the structure of which has been established by synthesis, a C30
aromatic alcohol, and a hydroxy ketone containing a cyclopropane ring, have
been isolated.
Synthesis and some annelation reactions of 1,4-diketones
Authors: Ritchie E , Taylor WC
Published: September 2010

Methods for the synthesis
of 1,4-diketones are briefly reviewed. A new route to 1,4-diketones involves
the Wittig reaction between the stable ylides, Ph3PCHCOCH3
and Ph3PCHCOPh, and 1,2-diones, followed
by seduction of the (E)-diacylethylene. ��� Pyrolysis of diphenacylsulphone yields a
derivative of thiet 1,1- dioxide. Phenylglyoxal, acetic anhydride, and pyridine
give ?dibenzoylformoin diacetate?, probably by a
benzoin condensation involving catalysis of a novel type. ��� Annelation reactions of 1,4-diketones are
reviewed. The reactions with indole have been extended. The structures of the
products from pyrogallol (trihydroxy-naphthalenes), and from quinol and 1,4- dihydroxynaphthalene
(anthraquinones) have been established.
Nuclear magnetic resonance spectra of 1,4-Dihydro- 1,4-ethenoisoquinolin-3(2H)-ones
Authors: Bauer L , Bell CL , Brophy GC , Bubb WA , Sheinin EB , Sternhell S , Wright GE
Published: September 2010

The 100-MHz N.M.R. spectra
of four 1,4-dihydro-1,4-ethenoisoquinolin- 3(2H)-ones
were analysed and the relative signs of vicinal and allylic coupling constants
were determined in one of the series. The allylic coupling constants include
the largest positive value so far reported and appear to vary with substitution
in a manner analogous to that exhibited by coupling constants between meta
protons in benzene derivatives.
Cyclic hemiaminal formation in some N-unsubstituted azole aldehydes
Authors: Browne EJ
Published: September 2010

Cyclic hemiaminal formation
in solid X-unsubstituted azole aldehydes seems to be a general phenomenon when
stabilization factors and position of substitution are favourable. Previously
reported for 5- substituted 1,2,4-triazole-3-carbaldehydes and benzimidazole-2-
carbaldehyde, it has been found to occur also in some previously undescribed
aldehydes of pyrazole, imidazole, 3H-imidazo[4,5- b]pyridine, 3H-imidazo[4,5-c]pyridine,
and purine. In purine-8- carbaldehyde the hemiaminal may be accompanied by the
aldehyde hydrate. P.m.r. studies of the dimers, and
of the dipiperidino cyclic aminals derived from them, indicate that in some
cases more than one isomeric form is present.
Polysaccharides of tropical pasture herbage. V. A galactoglucomannan from Townsville lucerne (Stylosanthes humilis)
Authors: Alam M , Richards GN
Published: September 2010

After removal of pectic
substances, lignin, and hemicelluloses from Townsville lucerne stems, the
residual ?α-cellulose? contained significant amounts of mannose. Further
extraction with a mixture of sodium hydroxide and sodium borate gave a
galactoglucomannan which was partly purified by precipitation with barium
hydroxide to give a crude yield of 0.35% based on the α-cellulose or 0.12%
based on the original plant dry weight. Further purification by chromatography
on QAE- Sephadex gave a polymer which showed only one component on free
boundary electrophoresis in borate buffer. Its structure was determined by
periodate oxidation, Smith degradation, and methylation-hydrolysis. The
backbone of the polymer consists of glucose and mannose units, linked 1,4, but their
order within the chain is not known. The non- reducing end-groups are
glucopyranose and galactopyranose units in the ratio 1 : 4. The galactose may
be present as single unit substituents at a frequency of 1 galactose per 14 main-chain
units and all such substitution occurs at mannose units with none at glucose
units. The similarity of the optical rotation to that of galactoglucomannans
previously isolated from wood suggests that the majority of the glycosidic
linkages are β-oriented.
Substituted carbonyl derivatives of the Group VI transition metals. I. Complexes with Bis(diphenylarsino)methane
Authors: Colton R , Rix CJ
Published: September 2010

The reactions of the
potentially bidentate ditertiary arsine ligand bis-(diphenylarsino)methane,
dam, with the hexacarbonyls of the Group VI transition metals have been
investigated. N.m.r, spectroscopy has been used to determine the mode of
coordination of the ligand. In the compounds M(CO)5(dam), M(CO)4(dam)2,
and M(CO)3(dam)3 [M = Cr, Mo, W], dam is acting as a
monodentate ligand, but in M(CO)4(dam) it is acting as a normal
chelate coordinating to the metal through both arsenic atoms. In the cases of
molybdenum and chromium, only, a further type of complex M(CO)2(dam)
has been isolated. The results of N.M.R., infrared, and mass spectrometry,
together with other physical measurements, can only be explained on the
assumption that the ligand was coordinated to the metal by an arene π-linkage
and by one arsenic atom. This novel structure has been confirmed by a single
crystal X-ray diffraction study on the chromium compound.
Organothallium compounds. VII. β-Diketonatobis(pentafluorophenyl)-thallium(III) compounds and their coordination derivatives
Authors: Deacon GB , Garg VN
Published: September 2010

The complexes (C6F5)2TlX [X = MeCOCHCOMe (acac), CF3COCHCOMe (tfac), CF8COCHCOCF3 (hfac), PhCOCHCOMe (bzac), PhCOCHCOPh (dbm), or quinolin-8- olate (oxinate or ox)], have been prepared by reactions
between bromobis(pentafluorophenyl)thallium(III) and the appropriate sodium or
thallous β-diketonates or sodium quinolin-8-olate,
and react with equimolar amounts of 1,10-phenanthroline (phen)
or 2,2?-bipyridyl (bipy) to give the complexes (C6F5)2-
(phen or bipy)TlX (X = acac, tfac, or hfac), (C6F5)2(phen)TlX (X = bzac,
dbm, or ox), but not (C6F5)2(bipy)TlX (X = bzac, dbm, or ox). On reaction with triphenyl- phosphine oxide or
triphenylarsine oxide, the complexes (C6F5)2(Ph3PO or Ph3AsO)-TlX (X = acac, tfac, hfac, or dbm) and (C6F5)2Ph3AsOTl(ox)
have been obtained. From conductance and molecular weight measurements and
spectroscopic data, the complexes (C6F5)2TlX (except X = ox), (C6F5)2(Ph3PO or Ph3AsO)TlX, and (C6F5)2(phen or bipy)TlX, are considered
to be monomeric with chelated β-diketonate or oxinate groups, and hence to
contain four-, five-, and six-coordinate thallium respectively, whereas (C6F5)2Tl(ox) is considered to have an associated
structure with bridging oxinate groups.
Studies of oxidations by Fenton's reagent using redox titration. III. Reactions with carbohydrates and polyhydroxy compounds
Authors: Ingles DL
Published: September 2010

The oxidation of
carbohydrates and some other polyhydroxy compounds by Penton's reagent has been
studied by redox titration at constant oxidation potential. Such compounds were
oxidized by a cyclic process involving the formation of enediols which reduced ferric
ion. The possible significance of these reactions is indicated. The peroxide
consumed in the complete oxidation of carbohydrates and some polymers was
measured in the absence and presence of oxygen.
Reactions of some halogenocyclohexadienones
Authors: Crozier RF , Hewitt DG
Published: September 2010

Chlorination of 2,4-, 2,6-
and 3,5-di-t-butylphenols gave the chlorocyclohexa-dienones
(2a), (10), and (7) and (9), respectively. Base-catalysed methanolysis of the
ketones (2a) and (9) produced the rearranged gem-dimethoxycyclohexadienones (5)and
(11). Under similar conditions the ketone (7) rearranged to 3,5-di-t-butyl-2,4-
dichlorophenol, while (10) was converted into a mixture
of 2,6-di-t-butyl-1,4-benzo-quinone and 3,5,3',5'-tetra-t-butyl-4,4'-diphenoquinone.
The dibromocyclohexa-dienone (2b) also dimerized in the presence of base, affording a low yield of
2,2'-dihydroxy-3,5,3',5'-tetra-t-butylbiphenyl. The mechanisms of these
reactions are discussed.
Chemistry of the metasternal gland secretion of the common eucalypt longicorn, Phoracantha semipunctata (Coleoptera: Cerambycidae)
Authors: Moore BP , Brown WV
Published: September 2010

The metasternal
gland secretion of Phoracantha semipunctata
contains five significant volatile components, of which the most abundant is
2-hydroxy-6-methyl-benzaldehyde (1). The second most abundant component, which
has been named phoraoanthol, has been shown by
synthesis to be (5-ethylcyclopent-1-enyl)methanol (2). The three other components
are aldehydes, derivable from phoracanthol and cis- and trans-dihydrophoracanthols, respectively.
Apparently all five components are related
biosynthetically.
Studies using radioisotopes. IV. The acid-catalysed rearrangement of 4-Hydroxy-3-nitroso-2-quinolones
Authors: Prager RH , Ting KY
Published: September 2010

4-Hydroxy-3-nitroso-2-quinolone
and its N-methyl derivative have been
labelled with 14C at C2, C3,
and C4, and the acid-catalysed rearrangement to isatin and isatoxime
studied. Carbon dioxide arises from C2, and the trace of carbon monoxide from
C4. Possible reaction pathways are discussed, and evidence is presented that dioxindole is implicated as an intermediate.
A convenient preparative method for esters of amino acids
Authors: Maclaren JA
Published: September 2010

The amino groups of amino
acids can be protected by using ethyl ecetoacetate as
a ,β-dicarbonyl component. The resulting derivatives are readily alkylated
at the carboxyl group by substituted benzyl and other halides. Mild acidolysis then removes the amino protection to give the
salt of the amino acid ester. This three-step synthesis can be performed
without isolation of intermediates and provides a convenient preparative method
for 4-methoxybenzyl, 2,4,6-trimethyl-benzyl, 4-nitrobenzyl, and 4-picolyl esters
of amino acids. The products are not racemized.
Carbonyl halides of the Group VI transition metals. XXVI. Nitrosyl halide complexes of molybdenum(II) and tungsten(II) with Bis(diphenyl-phosphino)methane and Bis(diphenylarsino)methane
Authors: Bowden JA , Colton R , Commons CJ
Published: September 2010

The known polymeric
molybdenum nitrosyl halides [Mo(NO)2X2 (X = Cl, Br) have been prepared by
the action of nitric oxide on Mo(CO)4X2. Derivatives of
these complexes with bis(diphenylarsino)methane (dam)
and its phosphine analogue (dpm) were prepared by direct
interaction. In addition, complexes containing dam were formed by the action of
nitric oxide on M(CO)2(dam)2X2 (M = Mo, W; X =
Cl,Br,I). All compounds isolated were of the form M(NO)2LX2
and M(NO)2L2X2 (L = dam or dpm).
Differences between the
nitrosyl halide derivatives and the corresponding carbonyl halide complexes are
interpreted on the basis of a steric argument.
Anthracene fluorescence at low temperatures. II. Doped single crystals
Authors: Lyons LE , Warren LJ
Published: September 2010

By the addition of dopants to single crystal anthraoene
it is shown that many of the fluorescence bands additional to exciton emission are due to traces of 2-methylanthracene.
Other impurity bands, apparently arising from locally disorientated host
molecules, appear on doping with most of the following, the effects increasing
in the order given: carbazole, biphenyl, p-terphenyl,
anthraquinone, naphthalene, naphthacene, phenanthrene, pyrene, chrysene.
The host vibronic bands were virtually unaffected by dopants, except for small line shifts in the presence of
2-methylanthracene.
Radical stabilization energies : The β-alkoxy group from kinetics of the thermal isomerization of 1-Chloro-4-methoxymethylbicyclo[2,2,0]hexane in the gas and liquid phase
Authors: Cain EN , Solly RK
Published: September 2010

The kinetics of the thermal
isomerization of 1-chloro-4-methoxymethyl- log(kb/s-1)
= (14.1 � 0.2)-(36.2 � 0.5)/θwhere θ = 2.303RT
kcal/mol and the subscripts g, a, and b refer to the gas phase, nitrobenzene-d5
as solvent, and diphenyl ether as solvent respectively. The Arrhenius
parameters are discussed in terms of transition state estimates for a biradical mechanism. With reference to the isomerization of
bicyclo[2,2,0]hexane and 1,4 dichlorobicyclo[2,2,O]hexane,
the α-methoxymethyl group is shown to
destabilize the biradical by 6.1 � 2.4 kcal/mol by
comparison with an α-propyl group. This radical destabilization by the β-ether
oxygen atom is explained in terms of the inductive effect of the β-electronegative
atom.
The thermal decompositions of carbamates. II. Methyl N-methylcarbamate
Authors: Daly NJ , Ziolkowski F
Published: September 2010

Methyl N-methyloarbamate decomposes in the range
370-422� to give methyl isocyanate and methanol. The
reaction is first order in carbamate, and the variation of the rate constants
with temperature is given by the equation.

k = 1012.39 exp(-4806O/RT) (s-l; activation
energy in cal mol-l)

Rate constants are
unaffected by the addition of isobutene or by increase in the surface to volume
ratio of the reaction vessel. The addition of alcohols or amines does not
reverse the process. The decomposition is considered to be a homogeneous, unimolecular gas-phase reaction, probably proceeding
through a four-centred transition state.
Oxidation of carbohydrates with chromium trioxide in acetic acid. IV. Conversion of cyclic methylene acetals into cyclic carbonates
Authors: Angyal SJ , Evans ME
Published: September 2010

Addition of acetic
anhydride to the reagent, chromium trioxide in acetic acid, changes the outcome
of the oxidation of cyclic methylene acetals, giving
cyclic carbonates in addition to formyl ketones.
Five-membered acetals (acetylated 3,4-O-methylene-D-mannitol and-L-iditol) give good yields of the carbonates, which are
readily isolated as diisopropylidene derivatives.
Six-and seven-membered acetals (acetylated 2,4-O-methylene-D-glucitol and 2,5-O-methylene-D-mannitol) give poor yields of
carbonates, which are unstable under the acid conditions used for deacetylation: the carbonate group migrates or is removed.
Molecular weight distribution of block copolymers by gel permeation chromatography
Authors: Urwin JR , Girolamo M
Published: September 2010

Molecular weight
distributions for block copolymers of polystyrene and

polyisoprene have been determined by gel permeation
chromatography for a series of well characterized polymers. Universal
calibration curves from [η]M against elution volume and by plots of
unperturbed dimensions (ro2)� against elution
volume have been constructed and examined. Normal-probability curves have been
used to calculate the heterogeneity ratio MW/MN and the
results compared with values from light scattering measurements and from
osmometry.
Phytochemical Survey of the Heartwood Flavonoids of Acacia Species From Arid Zones of Australia
Authors: Clark-Lewis J , Porter L
Published: September 2010

Examination of heartwoods from 14 species of Acacia collected from arid
zones of Australia gave flavonoids in which the main components showed phenolic
hydroxylation patterns typical of the subsections of the genus. In each case the
main flavonoids were accompanied by minor components possessing hydroxylation
patterns different from those of the main constituents. 3-Methoxyflavones were
widely distributed in the species examined, and 8-methoxflavan-3,4-diols were
detected in two species. Methylated flavonoids isolated include 7,8,4'-trihydroxy-3-
methoxyflavone, 7,8,3',4'-tetrahydroxy-3-methoxyilavone, 7,3',4'-trihydroxy-3,8-
dimethoxyflavone, and 7,3',4'-trihydroxy-8-methoxyflavonol. Attention is drawn
to the similar chromatographic and light-absorption properties of fisetin, 8-methoxy-
fisetin, and 7,8,4'-trihydroxyflavonol.
Azatropones and azatropolones
Authors: Cooke RG , Russell IM
Published: September 2010

Two reactions have been
explored for the preparation of azepinones, benzazep-inones, and dibenzazepinones.
Sonn-M�ller reduction of morphanthridine-6,ll-dione
gave 11H-dibenz[b,e]azepin-11-one. Treatment of a series of azepinediones
with triethyloxonium fluoroborate
produced a number of ethoxyazepinones. Two products,
2-methoxy- and 2-ethoxy-4-hydroxy-5H-benz[f]azepin-5-one,
appear to be the first examples of true azatropolone
derivatives.
Cope rearrangement and internal cycloaddition of 5-Allyl-3,3,5-trimethyl-1-pyrroline 1-Oxide
Authors: Bapat JB , Black DSC , Brown RFC , Ichlov C
Published: September 2010

5-Allyl-3,3,5-trimethyl-1-pyrroline 1-oxide(5)undergoes thermal Cope rearrangement to
5-allyl-2,4,4-trimethyl-1-pyrroline I-oxide(6)and
further cyclization to 1,6,6-trimethyl-9-oxa-8-azatricyclo[3,2,l,l9,8]nonane (7).
5H-Indeno[1,2-d]pyrimidin-5-ones
Authors: Demerac S , Dalton LK , Elmes BC
Published: September 2010

2-(1?-Ethoxyethylidene)indandione
(4) and formamidine react to give 4- methyl-5H-indeno[1,2-d]pyrimidin-5-one
(5a). Similarly 2-methyl-(5b), 2-trichloro-methyl- (5c), 2-trifluoromethyl- (5d),
2-amino- (5e), and 2-methylthio-4-methyl-5H-indeno[1,2-d]pyrimidin-5-one (5f)
have been prepared using the respective amidines, guanidine, or
methylisothiourea. Urea and thiourea failed to react and gave instead molecular
addition compounds. ��� 2-Hydroxymethyleneindan-1-one
(6) with urea or thiourea reacts to give the 2-(ureidomethylene)-(7a) or 2-(thioureidomethylene)-indan-1- one
(7b). All attempts to cyclize these compounds to give pyrimidines failed. ��� The alkaline hydrolysis and bromination of
the indenopyrimidines have been investigated.
Photochemical synthesis. VI.The formation of benzosemibullvalene derivatives in the photoaddition of diphenylacetylene to methyl 2-naphthoate, a degenerate thermal isomerization of the benzosemibullvalene skeleton
Authors: Sugowdz G , Collin PJ , Sasse WHF
Published: September 2010

Six compounds that comprise
up to 80% of the mixture formed on ultraviolet irradiation of diphenylacetylene
and methyl 2-naphthoate have been isolated and characterized by a combination
of spectral and chemical methods. Two of these compounds [(4) and (7)] are
derivatives of 1a,2,7,7a-tetrahydro-1,2,7-metheno-1H-cyclopropa[b]naphthalene,
two [(5) and (6)] are derivatives of benzosemibullvalene,
and two [(8) and (9)] are lactones derived from (6) and (4), respectively. The
yields of individual products of this photoaddition vary with the ratio of the
reactants and the solvent (benzene or cyclohexane). Certain aspects of the
mechanism of the formation of (4) and (5) are discussed, including the intermediacy
of the bicyclo[4,2,0]octa-2,4,7-trienes (12) and (37) and the role of methyl
2-naphthoate as sensitizer in the photoisomerization of (4) to (5). The thermal
interconversion of the benzosemibullvalenes (5) and
(6) between c. 15 and 110� is described, as well as the thermal isomerization
of (4) and (7) to derivatives of benzobicyclo[4,2,0]octa-2,4,7-triene.
An efficient synthesis of the lactone (8) by a novel lactonization procedure is
reported.
Chemical studies of the Proteaceae. V. Synthesis of derivatives of 5-n-Alkylresorcinols and related compounds
Authors: Nimgirawath S , Ritchie E , Taylor WC
Published: September 2010

A convenient reaction
sequence in which the key step is a Stevens rearrangement, leading to dimethyl
ethers of 5-n-alkylresorcinols has been developed and exemplified by the
synthesis of the dimethyl ethers of the natural phenols, dihydropersoonol, grevillol, and bilobol. The
tetramethyl ether of bis-norstriatol was also synthesized by the same route.
Radical cation formation during the adsorption of polycyclic aromatic hydrocarbons on platinum oxide
Authors: Garnett JL , Nicol KJ , Rainis A
Published: September 2010

Experimental conditions are
reported for resolving the hyperfine splitting of e.p.r. spectra obtained from
the interaction of polycyclic aromatic hydrocarbons with platinum oxide. By
contrast with earlier interpretations where only a singlet was obtained even
with perylene, the present results indicate that the adsorbed species are
radical cations.
The aggregation and reaction with oxygen of the tetrasodium salt of cobalt phthalocyanine-4,4',4'',4'''-tetrasulphonic acid
Authors: Gruen LC , Blagrove RJ
Published: September 2010

The reversible addition of
molecular oxygen to the tetrasodium salt of cobalt phthalocyanine-4,4?,4?,4??-tetrasulphonic
acid in aqueous solution has been confirmed. Visible absorption spectra of the
monomeric and dimeric species and of the oxygen adduct have been determined. A
monomer-dimer system prevails at neutral pH, low ionic strength, and low dye
concentrations. The oxygen adduct and the dimeric form of the dye predominate
in alkaline solution.
The synthesis of 2-Alkyl- and 2-Acyl-imidazoles by substitution methods
Authors: Begg CG , Grimmett MR , Yu-Man L
Published: September 2010

Imidazole and some
1-alkylimidazoles are methylated at C2 under homolytic methylation conditions.
Pyrazole forms 3-methylpyrazole, while 2-substituted imidazoles are unaffected.
Some 2-acylimidazoles are prepared and described.
Methyl group exchange reactions of trimethylaluminium dimer
Authors: Krankovits EM , Magee RJ , Murray KS , O'Conner MJ
Published: September 2010

Variable temperature
susceptibility measurements have been made on a number of
bis(N,N-dialkylmonothiocarbamato)nickel(II) complexes. The results are
characteristic of ferromagnetically coupled NiII clusters. Within
the range 300-80 K the susceptibilities can be fitted extremely well to a
number of possible cluster models and it is not possible to distinguish the
exact molecularity. ��� Measurements on one of the complexes down
to liquid helium temperatures confirm the ferromagnetic behaviour and demonstrate
inter- cluster interaction at very low temperatures. The magnetic behaviour of
these complexes contrasts with the diamagnetism of the square planar
bis(N,N-dialkyldithiocarbamato) analogues.