bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of methyl radicals. I. Hydrogen abstraction from dimethyl sulphide
Authors: Arthur NL , Lee M
Published: September 2010

Hydrogen abstraction from

(CH3),S and CH3COCH3 by CH3
radicals

CH3+CH3SCH3 → CH4+CH3SCH2

CH3 + CH3COCH3 → CH4 +
CH3COCH2

has been studied in the
temperature range 120-245�. The rate constants, based on the value of 1013.34cm3
mol-l s-1 for the recombination of CH3
radicals, are given by (k in cm3 mol-1 s-1, E
in kJ mol-1, R = 0.008314 kJ K-1 mol-1):

logk1 = (11.62 �
0.08) ? (38.35 � 0.68)/2.303RT

logk3 = (11.61 �
0.05) ? (40.48 � 0.46)/2.303RT

Combination of the results
for (1) with thermochemical data gives a calculated value of

Logk-1 = (11.8
-63.7/2.303RT

for the rate constant of
the reverse reaction. The results for CH3+(CH3)2S
are compared with all of the available data for hydrogen abstraction by free
radicals from both sulphur-containing compounds, and
molecules of the type (CH3)xM.
Chiral benzylidene derivatives of glycerol
Authors: Carman RM , Kibby JJ
Published: September 2010

Chiral benzylidene
derivatives of glycerol, the [(2R,4S)- and (2S,4S)-2-phenyl-1,3-dioxolan-4-
yl]methanols (3a) and (4a), together with some simple derivatives, are
reported.
Insect Moulting Hormones: The Synthesis of Ecdysone Analogues From a Bile Acid
Authors: Kinnear J , Martin M , Horn DS , Middleton E , Wilkie J , Galbraith M , Willing R
Published: September 2010

A new general synthesis of
2-deoxyecdysone analogues starting from the bile acid, chenodeoxycholic
acid, has been developed and used to prepare a number of ecdysones
for structure-biological activity studies.
Crystal structure of Tris(N,N-dibutyldithiocarbamato)iron(III) benzene solvate
Authors: Mitra S , Raston CL , White AH
Published: September 2010

The crystal structure of
the title compound, [Fe(CS2NBu2)3],C6H6,
has been determined at 295 K from diffractometer data and refined by least
squares to a residual of 0.071 for 3077 'observed' reflections. Crystals are
orthorhombic, Pncn,
a = 23.660(9), b = 17.331(7), c =
10.349(9) �. Unlike the unsolvated derivative, the
present compound has a magnetic moment of 3.6 B.M. at 295 K. Its molecular
symmetry is 2, (FeS) being 2.34, �. The role of the
benzene solvent, at a lattice site, is not indicative of any strong
intermolecular interaction.
Excitation spectra of the triplet states of some model lignin compounds
Authors: Smith GJ , Miller IJ , Melhuish WH
Published: September 2010

The triplet state
excitation spectra of a number of model lignin compounds have been determined
by measurements of the electron spin resonance signals associated with their
triplet states in low-temperature glasses at 110 K. The optimum wavelengths for
excitation of these triplet states were found to be in the tail of the main
absorption band at 320-340 nm. It is postulated that excitation in the main
band is inefficient in producing triplet states because of an alternative
pathway for energy degradation.
The chemistry of pyrrolic compounds. XXXIII. The synthesis of a β-nitroporphyrin
Authors: Clezy PS , Diakiw V
Published: September 2010

The first preparation of a β-nitroporphyrin is described.
Lichens and fungi. XIV. A revised structure for retigerane triterpenoids
Authors: Corbett RE , Heng CK , Wilkins AL
Published: September 2010

The structure of
retigeradiol, a triterpenoid diol previously considered to be
taraxerane-3β,19β-diol, is revised to that of
stictane-3β,22α-diol.
The cyclization of some methylphenylhydrazones to indoles. The preparation of some polymethine dyes related to Astrazon Orange R
Authors: Gale DJ , Lin J , Wilshire JFK
Published: September 2010

The cyclization of several
substituted acetophenone methylphenylhydrazones to indoles has been achieved by
means of polyphosphoric acid as the reagent. The resultant N-methyl-2- phenylindoles and their 3-formyl analogues were used for
the preparation of several new polymethine basic dyes related to Astrazon
Orange R, the ultraviolet spectral and lightfastness (on wool) properties of which
are described. The cyclization of some cycloalkanone methylphenylhydrazones has
been achieved in acetic acid.
Autoxidation catalysed by transition metal complexes. I. The coordinative mechanism for phenylmethanethiol autoxidation catalysed by Bis[dimercaptomaleonitrilato(2 -)]cobaltate(2-) [Co(mnt)2]22- in acetonitrile solution
Authors: Dance IG , Conrad RC
Published: September 2010

The homogeneous catalysis
of phenylmethanethiol autoxidation
���������������������� 2PhCH2SH+O2
→ PhCH2SSCH2Ph+H2O2
by [Co(mnt)2]22-
(mnt, doubly deprotonated dimercaptomaleonitrile) in
acetonitrile solution buffered with excess PhMe2N and PhMe2NH+ClO4-
at 18.0�C is described. Effective catalysis occurs in this medium, with
catalyst complex decomposition less than 1 mole % of the turnover.
Spectrophotometric and oxygen-consumption kinetic data indicate that the
mechanism involves initial coordination of the thiolate to [Co(mnt)2]- to form an intermediate which
then, with Bronsted acid assistance, interacts with
oxygen to form a second intermediate, which dissociates to products and
regenerates [Co(mnt)2]22-.
It is concluded that the role of the catalyst is to sequentially coordinate and
activate the reactants and facilitate intramolecular electron transfer from
thiolate to oxygen, without itself undergoing reduction or oxidation or
dithiolene ligand substitution.
Cyclic hydroxycarboxylic acids. IV. Synthesis of 2,3-cis-2,3-Dihydroxycyclopentanecarboxylic acid derivatives
Authors: Philp RP , Robertson AV
Published: September 2010

cis-α-Glycolation with
KMnO4 or OsO4 of methyl cyclopent-2- enecarboxylate
yields mixtures of methyl c-2,c-3- and t-2,t-3- dihydroxycyclopentane-r-1-carboxylates
which are difficult to separate. The derived dihydroxy acids and their
acetonides, and the acetonides, diacetates, bis-trifluoroacetates, and
ditosylates of the esters are characterized as mixtures in the two
diastereomeric families that have defied usual preparative separation
procedures. None of the products is crystalline, and only some of them show two
components by g.l.c. or p.m.r. examination, so close is their polarity.
Fluorine magnetic resonance studies. III. Fluorine-fluorine coupling over six and seven bonds in fluorostyrenes
Authors: Burgess DA , Rae ID , Snell JD
Published: September 2010

The 19F nuclear
magnetic resonance spectra of β,β-difluorostyrenes
and 1-difluoromethyleneindans bearing fluorine substituents in the aromatic
ring have been recorded and the long-range couplings 6JF,F
and 7JF,F are discussed. In each compound the larger couplings
are to the olefinic fluorine trans to the aromatic ring. The couplings are
maximum in the planar indans, reducing to unobservable values when
non-planarity is achieved in suitably substituted styrenes. The allylic
coupling 4JH,F involving olefinic fluorines shows only
slight stereochemical dependence.
Mass spectrometric studies. XII. Organic sulphates
Authors: Lloyd EJ , Porter QN
Published: September 2010

The mass spectra of
dimethyl and diethyl sulphates contain intense rearrangement ions resulting
from expulsion of sulphur trioxide subsequent to α-cleavage. The cyclic
sulphates from 1,2-diols fragment quite differently to the analogous sulphites,
and the mode of fragmentation appears to depend in a non-specific way on the
substituents present. The sulphates of 1,3-diols fragment in an orderly manner
via M-SO3 ions, which are best represented as oxetan radical
cations, while limited data for sulphates of 1,4-diols suggest fragmentation
via tetrahydrofuran-like intermediates.
Depsidone synthesis. VIII. Isolation and structural determination of Hydroxy-and Methoxy-colensoic acids. Synthesis of methyl Methoxy-O-methylcolensoate
Authors: Djura P , Sargent MV , Elix JA , Engkaninan U , Huneck S , Culberson CF
Published: September 2010

The isolation and
structural determination of the lichen depsidones 4,8-dihydroxy-3-methoxy-11-oxo-1,6-dipentyl-11H-
dibenzo[b,e][1,4]dioxepin-7-carboxylic acid (3) and
8-hydroxy-3,4- dimethoxy-11-oxo-1,6-dipentyl-11H-dibenzo[b,e][1,4]dioxepin-7-
carboxy1ic acid (4) are described. These structures are supported by the
synthesis of methyl 3,4,8-trimethoxy-11-oxo-1,6-dipentyl-11H- dibenzo[b,e] [1,4]dioxepin-7-carboxylate (5).
Simple pyrimidines. XVI. A synthetic route to some 2-(Pyrimidin-2'-yl)acetic acids and esters
Authors: Brown DJ , Waring P
Published: September 2010

A general route to the
hitherto inaccessible 2-(pyrimidin-2?-yl)acetic acid (3a), its 4?-substituted
derivatives, and their esters is described. For example, amidinoacetamide (1; R1
= R2 = NH2) and ethyl benzoylacetate (2; R = Ph) give
2-(4?-hydroxy-6?-phenylpyrimidin-2?- yl)acetamide
(3m) which with phosphoryl chloride gives 2-(4?-chloro-6?- phenylpyrimidin-2?-yl)acetonitrile
(3n). The nitrile is converted into the corresponding imidic ester (3o) and
thence into the carboxylic ester (3p) which undergoes dehalogenation to methyl
2-(4?- phenylpyrimidin-2?-yl)acetate (3q) and subsequent hydrolysis to 2-(4?-
phenylpyrimidinyl)acetic acid (3r).
The amidomethylation and bromination of Fischer's base.The preparation of some new polymethine dyes
Authors: Gale DJ , Lin J , Wilshire JFK
Published: September 2010

The amidomethylation of
Fischer's base (1,3,3-trimethyl-2- methyleneindoline)
with N-hydroxy-methylphthalimide gives, as the main product, the
5-phthalimidomethyl derivative (4). This compound has been converted into its
parent amine (5) from which a N-chloroacetyl derivative (6) was readily
obtained. Fischer's base reacted with one equivalent of dibromoisocyanuric acid
to give the 5-bromo derivative (7) and with two equivalents to give the
5,6-dibromo derivative (8). ��� All five substituted Fischer's bases have
been used to prepare representative polymethine dyes, the ultraviolet spectral
and lightfastness (on wool) properties of which are described. Dyes containing
one bromine atom impart particularly brilliant shades to wool. A dye containing
the N-chloro-acetamidomethyl substituent proved to be fibre-reactive.
The molecular structure of ammonia oxide (NH3O). An ab initio study
Authors: Radom L , Binkley JS , Pople JA
Published: September 2010

Ab initio molecular orbital
theory is used to determine the molecular structure of ammonia oxide (NH3O).
It is found that the N-O bond length is considerably overestimated by minimal
(STO-3G), split-valence (4-31G and 6-31G) and large sp basis sets. This fault
is rectified when polarization functions on nitrogen and oxygen are included in
the basis (6-31G*) leading to the best theoretical value for the N-O length of
1.377 A. Electron correlation has little effect on the calculated bond
length. Calculations (STO-3G and 4-31G) are also reported for trimethylamine
oxide.
1,6-Addition of t-butylmagnesium chloride to 9,10-phenanthraquinone
Authors: Cameron DW , Mingin M
Published: September 2010

Reaction between t-butylmagnesium
chloride and 9,10-phenanthraquinone takes an unusual course involving
1,6-addition. This leads successively to products based on 3-t-butyl- and
3,6-di-t-butyl-9,10-phenanthraquinone.
Neighbouring group participation by the carboxy group in the solvolysis of the dipeptides in acetic acid
Authors: Martin RJL , Schneider DS , Skovron CH , Yiu DLH
Published: September 2010

The acid-catalysed solvolysis of the dipeptides in acetic acid solution occurs readily both in the
presence and absence of water. The rates increase with increasing methylation, which is consistent
with a mechanism involving a ring-closure pathway by the terminal carboxy group. The experimentally
determined rate law is:
f × rate × [H2O]/[dipeptidium(1+) ClO4-][ΣH+] = k1 + k2[H2O]2
where f is the salt effect factor and ΣH+ is the acetic acidium perchlorate concentration after correcting
for the presence of oxonium perchlorate.
The k1 values increase with increasing methylation, as required for a ring-closure mechanism,
and the inverse water term in this component of the rate is ascribed to a medium effect. The ratecontrolling
step is defined as being the acid-catalysed ring fission of a rapidly formed intermediate,
oxazalone acetic acid solvate. The k2 component of the rate is first order with respect to water and
would appear to refer to the normal mode of solvolysis. But the much higher values of k2 for the
heavily methylated compounds as compared with Gly-Gly are incompatible with the much lower
activities shown by these compounds when reacting by the normal mode of solvolysis. Since k2
passes through a minimum with increasing methylation, it is suggested that it is a composite of the
normal and ring-closure modes of solvolysis. The rate-controlling step for this latter reaction is the
acid-catalysed reaction of water with the oxazolone acetic acid solvate. The increasing rates arising
from increasing methylation are due to increasing stabilities of the oxazolone solvate ring systems
resulting in a kinetically favourable displacement of this equilibrium towards the ring system.
Infrared analysis shows that the oxazolone of Aibu-Aibu readily undergoes a fast reaction with
acidified acetic acid to form a stable acetic acid solvate with the complete disappearance of all
oxazolone absorption frequencies. Aibu-Aibu on heating in acidified acetic acid solution rapidly
forms the same oxazolone acetic acid solvate with no evidence of any oxazolone absorption frequencies.
The solvolysis of optically active Gly-Val demonstrates that the oxazolone is not formed as an
intermediate because the Val produced retains its optical activity with no evidence of any racemization.
Vinylindenes and some heteroanalogues in the Diels-Alder reaction. II. Substituted fluorenes from 3-vinylindenes
Authors: Bergamasco R , Porter QN
Published: September 2010

3-Vinylindene,
2-methyl-3-vinylindene and 3-isopropenylindene give normal, photostable adducts
with ethenetetracarbonitrile by a Diels- Alder process. The first diene gives
adducts with maleic anhydride, N- phenylmaleimide and dimethyl
acetylenedicarboxylate. Where there is stereochemical ambiguity the adducts are
shown by mass spectrometry to be exclusively endo. Two heterocyclic analogues
are formed from 3- vinylindene with p-toluenesulphonyl cyanide and
N-sulphinyl-p- toluenesulphonamide.
1,3-Dipolar cycloaddition to a 1,4-quinone methide: 2,6-Di-t-butyl-4-methylenecyclohexa-2,5-dienone
Authors: Woolhouse AD
Published: September 2010

The reactive 1,3-dipoles ethoxycarbonylformonitrile oxide, benzonitrile oxide,
diphenylnitrile imine and benzonitrilium 4-nitrobenzylid add to the
4-methylenecyclohexa-2,5-dienone (1) to give the respective 1 : 1 cycloadducts
(4a-d). The yields are high and the reactions therefore provide ready access to
members of the hetero-spiro[4,5]decatrienone system. Diazomethane, phenyldiazomethane and diphenyldiazomethane also add to the
exocyclic methylene moiety of (1) to give only the nitrogen deficient spiro[2,5]octa-4,7-dienones
(10a-c).
Cyclopentadienyl-ruthenium and -osmium chemistry. IV. Convenient high-yield synthesis of some cyclopentadienyl ruthenium or osmium tertiary phosphine halide complexes
Authors: Bruce MI , Windsor NJ
Published: September 2010

High-yield one-pot
syntheses of RuCl(PR3)2(η-C5H5)
(R = Ph or p-MeC6H4) and OsBr(PPh3)2-
(η-C5H5) from ruthenium or osmium halides, the
tertiary phosphine and cyclopentadiene are described.
Second virial coefficients at 300-500 K for butane, tetramethylsilane and 'Freon 114'
Authors: Bottomley GA , Nairn DB
Published: September 2010

A constant-volume
gas-thermometer technique has been used at sub- atmospheric pressure to provide
second virial coefficients to above 500 K from initial values in the vicinity
of 300 K. The results for three organic vapours, butane, tetramethylsilane,
1,2-dichloro-1,1,2,2- tetrafluoroethane, are provided and expressed in terms of
the intermolecular parameters for the Lennard-Jones (12-6) potential and the De
Rocco and Hoover spherical-shell potential.
Tetrahedral bond length and angle variations in germanates
Authors: Hill RJ , Louisnathan SJ , Gibbs GV
Published: September 2010

Individual Ge-O bond
lengths of 24 germanate tetrahedra in solid materials are observed to increase
with decreasing 3, the average of the three O-Ge-O
angles common to each bond, and with 1/cos(Ge-O-Ge). These correlations are
examined in terms of valence electron population analyses obtained from
extended Huckel molecular orbital theory.
The use of Nε-2-Hydroxyarylmethylene-protected ornithine and lysine derivatives in solid-phase peptide synthesis
Authors: Abdipranoto A , Hope AP , Halpern B
Published: September 2010

Nα-t-Butoxycarbonyl-Nε-(2-hydroxyarylmethylene)-ornithine and -lysine have
been synthesized and coupled with amino acyl resins in the presence of
dicyclohexylcarbodiimide to form N-protected peptide resin esters. The ketimine
protecting group was found to be stable under anhydrous conditions and the
urethane blocking group could be removed preferentially. A number of lysine-
and ornithine- containing peptides have been synthesized by the solid-phase
technique.
The chemistry of Eremophila spp. VIII. A cembrenetriol from E. clarkei
Authors: Coates P , Ghisalberti EL , Jefferies PR
Published: September 2010

The isolation of a triol
(1) from the title plant is described. Reduction and deoxygenation of (1) leads
to the cembrane (12). The position of the primary hydroxyls is fixed by a
stereochemical argument and the relationship of the 1-hydroxy-1-methylethyl group
and the double bond is established through the pyrrole (14).
Crystal structure and stereoisomerism of Tris(O-ethylxanthato)antimony(III) in its lattice hemiadduct with 4,4'-bipyridyl
Authors: Kepert DL , Raston CL , White AH , Winter G
Published: September 2010

The preparation and crystal
structure determination of the adduct [Sb(S2COEt)3],0.5C10H8N2
is reported. Crystals are triclinic, Pī, a 6.064(3),
b 10.825(6), c 17.723(7) Ǻ, α 104.77(4), β 96.78(3), γ
97.14(4)°, Z 2. The compound is a lattice adduct, the bipyridyl molecule being
located about a crystallographic centre of symmetry. The complex molecule geometry
is unlike that of the compound [Sb(S2COEt)3];
in the latter the molecule has crystallographic symmetry 3, the three
equivalent ligands being unsymmetrically coordinated, while in the present
molecule the chirality is lost, the molecule conforming to approximate pseudo-m
symmetry: two ligands are similar [Sb-S, 2.615(2),
2.892(2); 2.612(2), 2.878(2) Ǻ] and the other, located in the
pseudo-mirror plane, is different [Sb-S, 2.477(2),
3.091(2) Ǻ]. Electron-pair repulsion theory shows that the bond angles,
the relative bond lengths, and the coexistence of different stereoisomers of
this molecule, can be ascribed to the stereochemically active lone pair of
electrons being close to the antimony atom.
The anomalous phosphorescence excitation spectra of model lignin compounds
Authors: Melhuish WH , Miller IJ
Published: September 2010

The anomalous
phosphorescence spectra of lignin model compounds at 77 K are explained in
terms of the formation of molecular aggregates (K ≈ 50 mol-1
1.). Aggregation best explains the phosphorescence excitation spectra and the
increase in phosphorescence yield (Yp) with increasing
concentration; for example, for isosafrole in ethanol at 77 K, Yp is
less than 0.005 at 10-5 M and c.0.1 at 3 × 10-2 M.
Studies of the thermal N 3 to N 9 rearrangement of the 3-β-D-Glucoside of the cytokinin, 6-benzylaminopurine
Authors: Eichholzer JV , Macleod JK , Summons RE
Published: September 2010

The initial observation of
a rearrangement of the glucosyl residue from N 3 to N 9 during g.c.-m.s. of derivatives of the 3-β-D-glucosyl
metabolite of 6-benzylaminopurine (1) has been further investigated by g.c., g.c.-m.s. and p.m.r. of the permethylated and perdeuteromethylated
derivatives of (1). Results show that the major process is a thermal
intramolecular 1,3-shift of the glucosyl grouping to the 9-position with
retention of configuration at the migrating centre, together with a smaller
contribution from an intermolecular 1,3-rearrangement which gives rise to both
the 9-α- and 9-β-anomers. An ionic mechanism is proposed to explain
both rearrangement processes.
Carbocyclic analogues of equol for the immunization of sheep against clover disease. I. Hydroxynaphthalenones
Authors: Loder JW , Eibl R , Falkiner MJ , Nearn RH , Parr RW
Published: September 2010

Racemic and optical isomers
of 7-hydroxy-3-(p-hydroxyphenyl)-3,4- dihydronaphthalen-1(2H)-one (1) have been
synthesized and the configurations of the optical isomers assigned by o.r.d. spectrometry. Derivatives of these
3,4-dihydronaphthalen-1(2H)-ones with aminooxyacetic acid were prepared and the
1,2,3,4-tetrahydronaphthalene (24) corresponding to (1) was synthesized.
Intermolecular and intramolecular chelate-linkage isomerism of some nickel oxime complexes
Authors: Lacey MJ , Macdonald CG , Shannon JS
Published: September 2010

Chelate-linkage isomers of
bis(3-hydroxyimino-4-iminopentan-2- onato)nickel(II) and bis(ethyl
2-hydroxyimino-3- iminobutanoato)nickel(II) have been prepared and
characterized.
Synthesis of benzofuranoid systems. IV. Total synthesis of cyperaquinone and conicaquinone
Authors: Macleod JK , Worth BR , Wells RJ
Published: September 2010

The total synthesis of the
novel naturally occurring benzodifuroquinones, cyperaquinone (1) and
conicaquinone (2), starting from phloroglucinol is described. A comparison of
synthetic and natural compounds confirmed the original structural assignments.
The key intermediate in the synthesis was the 3-methylbenzofuran (21) which was
prepared in high yield by an internal site-specific base-catalysed Ar1-5
cyclization of the acetonyloxy derivative (19). The method has also been
applied to the syntheses of linear furocoumarins and dibenzofurans.
Cembranoid constituents from an Australian collection of the soft coral Sinularia flexibilis
Authors: Kazlauskas R , Murphy PT , Wells RJ , Schonholzer P , Coll JC
Published: September 2010

Two new cembranoid lactones
have been isolated from Barrier Reef collections of Sinularia flexibilis. Other
metabolites include four previously reported macrocyclic diterprenes. The
structure and relative configuration of flexibilide (4), C20H30O4,
was determined by single- crystal X-ray diffraction methods. The colourless
crystals are orthorhombic, space group P212121,
a 10.682, b 30.404, c 5.779 Ǻ, Z 4.
Fluorescence decay of aromatic vapours. IV. Lifetime measurements on three further azabenzenes
Authors: Nott PR , Selinger BK
Published: September 2010

Lifetime studies of the
three azabenzenes s-triazine, pyridazine and pyrazine are reported. They show
quite different behaviour. Lifetimes of four single vibronic levels of
s-triazine were measured and show that an additional decay channel is
operating. The fluorescence from pyridazine is so fast that it was
indistinguishable from the exciting lamp pulse. Lifetimes of six single
vibronic levels of pyrazine were measured and were shown to be
pressure-dependent. These results fit quite well into the current understanding
of the behaviour of the azabenzenes.
Possible errors and ambiguities in the assignment of metastable peaks in mass spectrometry
Authors: Lacey MJ , Macdonald CG
Published: September 2010

A single (two-dimensional)
scan may not provide sufficient information to define unambiguously the
metastable ion reactions occurring in a double-focusing mass spectrometer, but
this ambiguity may be resolved by three-dimensional analysis of the ion-current
data. An analysis of data for diphenyl-methane demonstrates that single scans
may lead to incorrect assignments of the ions involved in certain reactions,
and of the location of the reactions in the flight tube.
Crystal structure of Tetraethylammonium Tetrakis(O-ethylxanthato)bismuthate(III)
Authors: Raston CL , White AH , Winter G
Published: September 2010

The crystal structure of
the title compound (NEt4) [Bi(S2COEt)4] has
been determined by single-crystal X-ray diffraction at 295(1) K and refined by
least squares to a residual of 0.051 for 1560 'observed' reflections. Crystals
are monoclinic, P21, a 10.947(2), b 16.334(4), c 10.589(2)Ǻ,
β 116.04(2)°, Z 2. The bismuth coordination stereochemistry is
dodecahedral, Bi-S ranging from 2.803(11) to 2.972(10) Ǻ; the three
longest distances occupy a triangular face in the coordination polyhedron and
may indicate the presence of a stereochemically active lone pair.
Chemistry of pyrrolic compounds. XLI. The synthesis of the phaeophorbides c1 and c2 methyl esters
Authors: Clezy PS , Fookes CJR
Published: September 2010

Phaeophorbide c1,
the magnesium-free derivative of chlorophyll c1, has been synthesized
as the methyl ester (1c) by means of the copper acetate cyclization of an
appropriately substituted bilene-b salt. Similar syntheses of phaeophorbide c2
methyl ester (1d) and isophaeophorbide c1 methyl ester (1g) have
been completed. Comparison of these synthetic compounds with natural material
both as the metal free derivative and as the magnesium chelate has
substantiated the accepted structures for the chlorophylls c.
Acidity Dependence of the Tautomeric Equilibrium Between the First Conjugated Acids of 4-Aminoazobenzenes
Authors: Yamamoto S , Tenno Y , Nishimura N
Published: September 2010

Acidity functions based
upon primary anilines which have no ortho substituents have been established in 20% ethanol-80%
aqueous sulfuric acid solutions, and compared with those based upon o-substituted anilines and azobenzenes. It was found that the tautomeric equilibrium
between azonium and anilinium
forms in 4-aminoazobenzene derivatives invariably shifts to the azonium form with increase in acidity. This observation has
been interpreted in terms of acidity functions.
N-Aminopyrimidines. The Synthesis and Reactions of 1-Aminobarbituric Acids
Authors: Jacobsen NW , McCarthy BL
Published: September 2010

A general synthesis of
1-aminobarbituric acid, 1-amino-2-thiobarbituric acid and their 5-alkyl
derivatives is described together with reactions and properties which confirm
their structure.
Some Phenoxybenzenesulfonyl Chlorides and Related Compounds
Authors: Cremlyn RJ , Cronje T , Goulding K
Published: September 2010

Phenoxybenzene (diphenyl
ether) has been converted into the 4-sulfonyl chloride (1) which on condensation
with various nucleophilic reagents gave a range of sulfonyl derivatives (2-11),
such as the azide, hydrazides, and hydrazones. The sulfonyl chloride (1), by
nitration, gave 4-(4'-nitrophenoxy)benzenesulfonyl chloride (12) which was
similarly converted into sulfonyl derivatives (13-18). Reaction of o-chlorophenol with p-chloronitrobenzene afforded 2-chlorophenyl 4-nitrophenyl ether;
with chlorosulfonic acid this gave the sulfonyl chloride (19) which was
converted into the sulfonyl derivatives (20)-(25). Condensation of
2,6-dichlorophenol with p-chloronitrobenzene
similarly gave the substituted diphenyl ether (26) which with chlorosulfonic
acid afforded 3,5- dichloro-4-(4'-nitrophenoxy)benzenesulfonyl chloride (27).
The phenoxybenzenesulfonyl derivatives are of interest as potential herbicides
and their algicidal and antibacterial properties are briefly discussed.
The Low-Temperature Magnetic Properties of Tris(acetylacetonato)molybdenum(III)
Authors: Gregson AK , Anker M
Published: September 2010

The average magnetic moment
of tris(acetylacetonato)molybdenum(III) has been
measured down to 1.5 K. In the magnetically dilute solution state the 4A2
ground state is well described by a S 3/2 spin Hamiltonian with g 1.94, g, 1.97
and D + 7.0 cm-1 or -6.3 cm-1; the ambiguity in sign can
be resolved by earlier electron spin resonance data which suggested that D is
negative. In the solid state there appears to be a very small antiferromagnetic
interaction.
Carbon-13 N.M.R. Spectra of Some Amides and Lactams and Their Thio and Seleno Analogues
Authors: Rae ID
Published: September 2010

13C N.M.R. spectra were determined, and resonances were
assigned, for 27 amides and lactams and their thio and seleno analogues.
Synthetic Plant Growth Regulators. IV. The Preparation of Hydroxylated Helminthosporic Acid Analogues
Authors: Mander LN , Palmer LT
Published: September 2010

Sequential reduction
(sodium borohydride, metal-ammonia, hydrogenation) of ketone (8) gave the
hydroxy ketone (9) which was converted into olefin (10) (Wittig
olefination) and thence to acid (14) by means of the
[2,3] sigmatropic rearrangement of ylide (12) to (13). Acid (15) was similarly prepared from
alcohol (11) which was obtained by deoxygenation of
ketone (9). The tetrahydrocuminic acid (16) was hydroxylated (lithium diisopropylamine,
oxygen); the new hydroxyl group was protected with a dichloroacetyl
function and then converted into the diazoketone. Lewis-acid-induced
cyclization of (17) gave the bicyclooctanone (18a)
plus its Δ3-isomer (18b), both of which were reduced and
hydrolysed to hydroxy ketone (19). Wittig methylenation of (19) gave olefin (20)
which was rearranged by acid to ketone (21). Both (20) and (21) were elaborated
further to the acids (6) and (25), respectively, by the procedures used in the
preparation of acids (14) and (15).
Cupressene and Other Diterpenes of Cupressus Species
Authors: Carman RM , Sutherland MD
Published: September 2010

Cupressene, as originally isolated from Cupressus
macrocarpa, is shown to be a 1 : 2 mixture of (+) isophyllocladene with (+)-isohibaene
(13α-beyer-15-ene) rather than with (-)-hibaene
(beyer-15-ene) as previously claimed. Corrections to the optical rotations of
(+)-phyllocladinol and (-)-abieta-7,13-diene and g.l.c. data for diterpene hydrocarbons are reported.
Analysis of the diterpene hydrocarbon composition of the foliage of 27
specimens from four Cupressus species reveals significantregularities.
Cobalt(III) Complexes of a Stereospecific Ligand Derived from (S)-Proline
Authors: Woon T , O'Conner MJ
Published: September 2010

The quadridentate ligand,
(2S,2'S)-1,1'-(ethane-1,2-diyl)bis(pyrrolidine-2-carboxylic acid) dihydrochloride
(H2pren,2HCl), has been derived from (S)-proline. The preparations
of the cobalt(III) complexes Na [Co(pren)(CO3)],3H2O,
[CO(pren)(H2O)2] ClO4,- 2H2O and
[Co(pren)(H2O)Cl],1�5H2O are described. All exist as cis-α geometrical isomers. 13C
N.M.R. and absorption spectral measurements confirm the cis-α arrangement. The complex cis-α- [Co(pren)(H2O)Cl],1�5H2O rapidly
aquates with retention of configuration. The compounds having actual or near C2
symmetry exhibit a strong negative c.d. band under the 1A1g
→ 1T1g cubic absorption band which is due to the 1A1
→1E tetragonal component, consistent with the Δ absolute
configuration imposed by the (S) configuration of the asymmetric carbon atom in
the (S)-proline moiety. The o.r.d. spectrum of cis-α-Na [Co(pren)CO3],3H2O in aqueous
solution has a negative Cotton effect at low energy as expected for the Δ
absolute configuration.
The Nitration of Brominated Pyrazoles in Aqueous Sulfuric Acid
Authors: Chang K , Grimmett MR , Ward DD , Weavers RT
Published: September 2010

Nitration in 80% sulfuric
acid of 4-bromopyrazoles gives rise to considerable nitrodebromination.
Compounds with no alkyl or aryl substituent on nitrogen give only the 4-nitro
products (except 4-bromo-3-phenylpyrazole which gives the p-nitrophenyl compound). N-Alkyl-4-bromopyrazoles give products of
nitrodebromination as well as those arising from nitration in the 3- and/or
5-positions. N-Aryl-4-bromopyrazoles
can also undergo nitration of the aryl substituent.
Methyleneketenes and Methylenecarbenes. XIV. Evidence for the Rearrangement of Cyclopent-2 enylidenecarbene to Benzene and of Cyclopentadienylidenecarbene to Benzyne
Authors: Armstrong RJ , Brown RFC , Eastwood FW , Romyn ME
Published: September 2010

Flash vacuum pyrolysis of
2,2-dimethyl-5-(endo-tricyclo[5,2,1,02,6]dec-8'-ylidene)-1,3-dioxan-4,6-dione
(2) at 550-800� yielded cyclopentadiene, acetone and benzene. The production of
benzeneis rationalized in terms of
the formation and rearrangement of cyclopent-2-enylidenecarbene (5).
2,2-Dimethyl-5-(octahydro-1',2',4'-metheno-1'H-cyclobuta[cd]pentalen-3'-ylidene)-1,3-dioxan-4,6-dione(7) yielded
cyclopentadiene, acetone, biphenylene (27 %), triphenylene (12 %) and
fluorenone (14%) as major products on flash vacuum pyrolysis at 550-700�. The
last three compounds are considered to arise from o-benzyne, formed by rearrangement of the intermediate cyclopentadienylidenecarbene
(9).
The Total Synthesis of Sinularene, a Sesquiterpene Hydrocarbon from the Soft Coral Sinularia mayi
Authors: Collins PA , Wege D
Published: September 2010

The sesquiterpene (�)-sinularene
(exo-5-isopropyl-2-methyl-7-methylenetricyco[4,4,0,02,8]decane)
has been synthesised by a 15-step sequence starting with anti-7-methylbicyclo[2,2,1]heptane-syn- 7, exo-2-carbolactone.
The Synthesis and Properties of Dimethyl 1,2-Diazetine-1,2-dicarboxylate, a Potentially Aromatic Molecule
Authors: Warrener RN , Nunn EE , Paddon-Row MN
Published: September 2010

The cyclobutene n-bond of dimethyl 2,3-diazabicyclo[2,2,0]hex-5-ene-cis-2,3-dicarboxylate (15) has
been employed as a dienophile in the Diels-Alder reaction with 2,5-dimethyl-3,4-diphenylcyclopenta-
2,4-dienone (17). The reaction occurred with high stereoselectivity and led, almost exclusively, to
the formation of the exo-fused adduct (18). A similar cycloaddition was performed between the
dienone (17) and the bicyclo[2,2,0]hex-5-ene-cis-2,3-dicarboxylic anhydride (5) to yield a 90 : 10
mixture of adducts (6). These several adducts were used as precursors for the preparation of the
related bicyclo[4,2,0]octa-2,4-diene derivatives (7) and (20), themselves used as photosubstrates for
the 1,2-photoaromatization reaction. In this way the carbocyclic precursor (7) yielded cyclobut-3-
ene-cis-1,2-dicarboxylic anhydride (8), and the hetero analogue (20) yielded the title diazetine (21).
Hydrogenation of this heterocycle yielded the related 1,2-diazetidine (22) which was fully
characterized. The reactivity of the diazetine, which formally contains six delocalized electrons,
is considered especially as it relates to its potential aromatic character. In practice the facile ring-
opening of the diazetine to the 1,4-diazabuta-1,3-diene (23) fairly reflects the lack of aromaticity
of this ring system.
An INDO MO SCF method has been used to evaluate the energetics of the nitrogen inversion process
in the unsubstituted 1,2-diazetine ring. The results indicate that the planar form lies at a maximum
on the energy surface and that there is little electron delocalization. The planar form is best described
as being antiaromatic. PMO arguments are presented which support this conclusion.
Crystal structure of Aquatetrakis(N-formylpiperidine)dioxouranium(VI) Bisperchlorate
Authors: Honan GJ , Kepert DL , Lincoln SF , Patrick JM , White AH
Published: September 2010

The crystal structure of
the title compound, [UO2{OCHN(CH2)5}4(H2O)]
(ClO4)2, has been determined by single-crystal X-ray
diffraction at 295 K and refined by least squares to a residual of 0.051 for
3113 'observed' reflections. Crystals are monoclinic, C2/c, a 16.945(2), b
12.711(2), c 17.304(2)Ǻ, β 107.76(1)°, Z 4. The uranyl moiety [U=O,
1.76(2)Ǻ] is five-coordinated in the equatorial plane by the water
molecule [U-O, 2.436(8)Ǻ] and four organic ligands [U-O, 2.379(8),
2.396(13)Ǻ]. The angles O-U-O in the equatorial plane range from 70.3(3)
to 73.6(3)°; O=U-0 range between 86.7 and 95.3°. The angle O=U=O is
177.8(3)°. The stereochemistry of seven-coordinate uranyl compounds is
examined by using repulsion theory.
Diffusion coefficients of two anionic dyes in dilute aqueous electrolyte solution
Authors: Craven B , Imamkhasani S
Published: September 2010

Diaphragm cells were used
to determine diffusion coefficients of two anionic dyes in dilute aqueous
electrolyte solution. Allowance was made for disaggregation occurring as dye
aggregates traverse the concentration gradient in the diaphragm, and an attempt
was made to account for such effects semi-quantitatively. Diffusion
coefficients of one of the dyes were measured polarographically, and the
results compared with those obtained using diaphragm cells. Steps in the curves
of diffusion coefficient against dye concentration suggest that at low
concentrations both dyes form dimers; as the
concentration is increased the dimers aggregate to
form tetramers.
Synthesis and structure of a monothiooxalato cobalt(III) complex
Authors: Gainsford GJ , Jackson WGSAM
Published: September 2010

The crystal and molecular structure
of racemic bis(ethane-1,2- diamine)(thiooxalato-O,S)cobalt chloride hydrate ([Co(en)2(mtox)] Cl,H2O) has been determined by
single-crystal X-ray diffraction techniques; all atoms, including hydrogens, have been refined by full-matrix least-squares
procedures to a final R index of 0.032. The crystals are monoclinic, space
group P21/c with a 7.548(1), b 14.249(2), c 12.317(2) Ǻ, β
109.27(1)°. The structure consists of discrete cations linked by hydrogen bonds
to the chloride anion, water molecule and symmetry-related cation. The Co-N
bond trans to Co-S is lengthened relative to the cis Co-N(en) lengths by
0.021(3) Ǻ. The complex is the only tractable product from the reaction of
excess acetic anhydride in dimethyl sulfoxide with [Co(en)2(SCH2CO2)]+
ions. The mechanism of formation is discussed.
A quantitative analysis of solvent effects on reaction constant
Authors: Poh B
Published: September 2010

Solvent effects on reaction
constant ρ for the dissociation equilibria of several series of organic acids
are analysed in terms of three factors, namely, (i)
variation in the effective dielectric constant, (ii) variation in the
hydrogen-bonding ability of solvents, and (iii) variation in the conformation
of the acids. A fourth factor, variation in the charge developed in the
transition state of the reaction, is included in the analysis of ρ for
reactions between diazodiphenylmethane and several series of carboxylic acids.
It is shown that the ρ values for the dissociation equilibria of series of
acids in other solvents can be calculated from their ρ values in water.
Vibrational spectra of complexes of mercury(I) and mercury(II) with pyridine and other nitrogen bases
Authors: Tan K , Taylor MJ
Published: September 2010

Raman and i.r. spectra of the series of compounds MeHg(pyx)ClO4, Hg(pyx)n(ClO4)2
and Hg2- (pyx)n(ClO4)2
(pyx = pyridine or a pyridine derivative; n = 2 or in
some cases 4) are reported. In the low- frequency region, the spectra of the
complex cations provide the basis of assignments of Hg-N (160-260 cm-1)
and Hg-Hg (110-160 cm-1) stretching frequencies.
Vapour pressure study of the deuterium exchange reaction in methanol-ethanol systems: equilibrium constant determination
Authors: Kooner ZS , Fenby DV
Published: September 2010

The equilibrium constant of
the reaction ���������������������� CH3OH(1)+C2H5OD(1)
→ CH3OD(1)+C2H5OH(1)
is obtained from vapour
pressure measurements on methanol+ethanol systems.
The value obtained, 1.03�0.01 at 298 K, is in good agreement with that calculated
independently from previously reported vapour pressure studies of water+methanol and water+ethanol
systems. Vapour pressures at 298.15 K are reported for the systems CH3OH+C2H5OH,
CH3OH+C2H5OD, CH3OD+C2H5OH
and CH3OD+C2H5OD. Molar excess Gibbs functions
are obtained from these vapour pressures.
Conformations of some 4- and 4,4'-Di-substituted benzophenones
Authors: Gore PH , John IG , Ritchie GLD
Published: September 2010

Experimental dipole moments
and molar Kerr constants are reported for eight 4- and 4,4?-halogeno- and
-methyl-benzophenones as solutes in carbon tetrachloride at 298 K. Analysis of
the results elucidates the conformational preferences of these molecules and
suggests that steric effects are of predominant importance, whereas the
additional conjugative interactions provided by the substituents apparently
play only a minor role.
A study of cations generated from 1- and 3-methyl- and 1,3- and 1,7-Dimethyl-2-arylbicyclo[2,2,1]heptan-2-ols
Authors: Coxon JM , Steel PJ
Published: September 2010

The 13C n.m.r.
spectrum of the 2-(4?-methoxyphenyl)-1- methylbicyclo[2,2,1]hept-2-yl
cation is reported and indicates a significant reduction in π-delocalization
of charge into the aryl ring on introducing a C1-methyl group. The
endo-3-methyl-2- phenylbicyclo[2,2,1]hept-2-yl cation
in strong acid undergoes epimerization at C3 and does not afford the tetracyclic or dimeric compounds. 1,exo-3-Dimethyl-endo-2-phenylbicyclo[2,2,1]heptan-exo-2-ol
on reaction with HSO3F gave the exo-3,endo-6-dimethyl-2- phenylbicyclo[2,2,1]hept-2-yl cation at temperatures above
-50°. This is the first alcohol containing a C1-methyl, C2-aryl system which
does not undergo a WM; 6,2H; WM rearrangement. Reaction of 1,syn-7-dimethyl-
endo-2-phenylbicyclo[2,2,1]heptan-exo-2-ol gave the parent 1,syn-7-� dimethyl cation which at -50° gave the
exo-5,endo-6-dimethyl-2- phenylbicyclo[2,2,1]hept-2-yl
cation but not the WM; 6,2H; WM product. The structural features which
determine the pathway of rearrangement of these bicyclic cations are discussed.
Cyclopentadienyl-ruthenium and -osmium chemistry. XII. Some complexes containing cyclic carbene ligands
Authors: Bruce MI , Swincer AG , Thompson BJ , Wallis RC
Published: September 2010

Reactions between ω-hydroxyalk-1-ynes,
HC2(CH2)nOH (n = 2 or 3) or HC2CH2CHMeOH,
and MX(PR3)2(η-C5H5) (M = Ru, X = Cl, R = Me or Ph; M = Os,
X = Br, R = Ph) in the presence of NH4PF6 give cationic
cyclic carbene complexes, presumably by rapid
intramolecular cyclization of (undetected) intermediate ω-hydroxyvinylidene
complexes. Further reactions of {Ru[C(CH2)3O]-(PPh3)2(η-C5H5)}+
include (a) base-catalysed H- D exchange of both H atoms of the β-CH2
group; (b) metallation and subsequent dimethylation of the β-CH2
group; (c) reduction by NaAlH2- (OCH2CH2OMe)2
to Ru[CH(CH2)3O](PPh3)2(η-C5H5).
Asymmetric induction in the additions of anions of allylic sulfoxides to benzaldehyde
Authors: Antonjuk DJ , Ridley DD , Smal MA
Published: September 2010

Addition reactions of
anions of aryl allyl sulfoxides to benzaldehyde proceed readily in moderate
yields and afford mixtures of products resulting from α- and γ-attack
on the allyl anion. The γ-products all possess the (E)-configuration
around the double bond, and asymmetric induction occurs in the addition to the
extent that the major/minor diastereomer ratio exceeds 2 : 1, generally.
Electronic factors are believed to be responsible for this 'remote' asymmetric
induction. Mixtures of all four possible diastereomers are observed in the
products from α-attack and evidence is presented which suggests that the
ratios of these products are as a result of epimerization of two of the chiral
centres by [2,3] sigmatropic rearrangement.
Furanosesquiterpenes from Eremophila rotundifolia
Authors: Dimitriadis E , Massy-Westropp RA
Published: September 2010

Two new furanosesquiterpenes,
7-methyl-7-(4'-methylpenta-1',3'-dienyl)- 4,5,6,7-tetrahydrobenzofuran and
4-hydroxydendrolasin [(S,E)-9-(furan- 3'-yl)-2,6-dimethylnona-2,6-dien-4-ol],
are described. The structure of the former compound was confirmed by synthesis
from dihydrophymaspermone and the structure and
stereochemistry of 4- hydroxydendrolasin were
established by synthesis from eremoacetal.
Ab initio studies on amides: triformamide
Authors: Radom L , Riggs NV
Published: September 2010

Complete optimization with the STO-3G
basis set of the geometries of the planar ground-state conformers of the
(unknown) triformamide molecule predicts that the
E,E,E conformer will be more stable than the E,Z,Z conformer by 12.6 kJ mol-1
(or 42.3 kJ mol-1 by energy evaluations with the 4-31G basis set).
These differences make direct observation of the E,Z,Z-conformer unlikely.
Corresponding optimization of a model transition state for the conversion of
the E,Z,Z into the E,E,E conformer suggests that the barrier to internal
rotation is low with a calculated height of 33 kJ mol-1 (24 kJ mol-1
when evaluated with the 4-31G basis set). Successive formyl substitution in
ammonia, represented by the series of molecules formamide,
diformamide (formimide) and
triformamide, leads to decreasing double-bond
character in the N-C bonds as reflected in increasing N-C bond lengths,
decreasing Mulliken π-overlap populations and decreasing barriers to rotation. Extension of
the results for these three molecules suggests that the (known) triacetamide molecule has a non-planar E,E,E-type structure
as is consistent with the observation of a single signal in its 1H
n.m.r. spectrum.
Electrophilic ipso-substitution of some highly functionalized tetrahydronaphthalenes
Authors: Cameron DW , Feutrill GI , Griffiths PG
Published: September 2010

The methoxy methyl tetralin
(1) underwent bromination, chloromethylation or formylation chiefly at position
8. This preference extended to ipso-attack
on the 8-bromo derivative in spite of position 6 being vacant.
Ion cyclotron resonance and deuterium kinetic isotope studies of the gas-phase reactions of the alkoxide negative ions with anhydrides and esters
Authors: Klass G , Underwood DJ , Bowie JH
Published: September 2010

(i) The i.c.r. spectrum of
the CD3O-/acetic anhydride system shows the occurrence of
the negative ion McLafferty rearrangement [reaction (1)] and the characteristic
elimination shown in reaction (2) (R = COMe)
CD3O-+
(MeCO)2O → (CD3O)(Me)(HO)C-O-+ CH2CO
(1)
CD30-+ MeCO2R → -CH2C02CD3+
ROH (2)
(ii) The i.c.r. spectra of CD3O-/alkyl ester
systems show major peaks due to [ester-H+]- ions,
together with small peaks corresponding to [ester+CD3O-]-
adducts. Carboxylate and alkoxide anions (derived from the ester) are also
observed in certain spectra; peaks due to these ions increase in intensity with
elaboration of alkyl substituents. Reaction (2) is characteristic of all esters
studied (illustrated above for acetates) which have at least one hydrogen
substituent on the carbon atom α to the carbonyl group. The reaction must
occur by nucleophilic attack of the alkoxide anion at the carbonyl group of the
ester. Negative ion McLafferty rearrangements do not occur in alkyl ester systems.
(iii) The H transfer reactions (1)
and (2) show deuterium isotope effects kH/kD of 3.0 and
1.5 respectively (when the carbon adjacent to the carbonyl group contains one
deuterium substituent). Isotope effect calculations suggest that reaction (1)
proceeds through a 'near symmetrical' six membered transition state, whereas
(2) goes through a 'reactant-like' but distorted four-centred transition state.
Halogenated terpenoids. XIX. The 24,25-dibromolanosteryl acetates
Authors: Carman RM , Venzke BN
Published: September 2010

The earlier assignment of
the structures of the two epimeric 24,25-dibromides of lanosteryl
acetate is reversed and is now consistent with deductions made from optical
rotation data. The two dibromides on heating
equilibrate to an approximately equimolar mixture.
The structures of the agnosteryl acetate dibromides and of the Ianosta-7,24-dien-3-yl acetate dibromides must also be revised, with the higher-rotating A
isomers having the 24R configuration in all cases.
Brominated tyrosine-derived metabolites from the sponge Ianthella basta
Authors: Kazlauskas R , Lidgard RO , Murphy PT , Wells RJ , Blount JF
Published: September 2010

Seven novel metabolites,
each originating from four bromotyrosine units, have been isolated from the
sponge Ianthella basta. Bastadin-1 (2),
bastadin-2(3) and bastadin-3(4) are derived from a single phenol oxidative
coupling whilst the macrocyclic compounds bastadin-4(5), bastadin-5(6),
bastadin-6(8) and bastadin-7(7) are formed by two phenol oxidative coupling
reactions. Compounds (2)-(8) showed potent in
vitro antimicrobial activity against Gram-positive organisms.
Generalized van der Waals theory. IV. Variational determination of the hard-sphere diameter
Authors: Hooper MA , Nordholm S
Published: September 2010

The generalized van der Waals theory is here extended
by incorporating the hard-sphere diameter as a variational parameter. Moreover,
the entropy functional has been chosen so as to accurately reflect the density
dependence of the excluded volume revealed by the hard-sphere equation of
state. The combined effect of these two improvements yields a theory capable of
describing the equation of state of the Lennard- Jones model of classical
fluids to an accuracy comparable to that of the pair correlation theories. The
results presented here include critical parameters and coexistence and vapour
pressure curves.