bluuebunny/crossref_metadata_2025 huggingface dataset:
Reaction of carbethoxynitrene with anthracene, phenanthrene, and pyrene
Authors: Beckwith ALJ , Redmond JW
Published: September 2010

Carbethoxynitrene,
generated by thermal decomposition of ethyl azido- formate, reacts with
anthracene to yield a mixture of 9-, 1-, and 2-anthrylurethane. Phenanthrene
when treated with carbethoxynitrene affords 9-, 1-, and 4-phenanthryl-urethane,
and pyrene is similarly converted into a mixture of 1- and 4-pyrenyl- urethane.
In any one substrate there is no simple relationship between the isomer ratio
and free-valence numbers or bond orders. The relative yields of products are
most easily rationalized in terms of a dichotomy of mechanism, the reaction
proceeding both by a direct substitution pathway (electrophilic or
free-radical) and via an aziridine formed by addition of carbethoxynitrene
across positions of high bond order.
Flavan derivatives. XVIII. Synthesis of hemiketals containing the peltogynol ring system: 3(3')-Hydroxyisochromano (4',3':2, 3) chromans. Conversion of 2'-hydroxychdcones into flav-3-enes and its biosyntheticimplications
Authors: Clark-Lewis JW , Skingle DC
Published: September 2010

Reduction of three 1?-oxoisochromeno(4?,3?:2,3)chromones [chromeno(3?,2?:
3,4)isocoumarins] with lithium aluminium hydride has been shown to yield 3(3?)-hydroxyisochromano(4?,3?:2,3)chromans (hemiketals). The
structures of these compounds (the 7-methoxy, 7,6?,7?-trimethoxy, and parent
hemiketals) were unequivocally established by N.M.R., mass spectral, and
chemical data. The hemiketals contain the peltogynol ring system, and one of
them is the 7,6?,7?- trimethyl ether of the structure originally proposed for
this leucoanthocyanidin by Robinson and Robinson. The
hemiketals were obtained as mixtures of cis- and trans- isomers which underwent
equilibration in deuterochloroform or in wet chloroform, and configurations
were assigned to the isomers from a detailed study of their N.M.R. spectra. The
hemiketals suffered dehydration when heated further in deuterochloroform, and
gave the isochromeno(4?,3?:2,3)chromens (flav-2-enes),
which immediately gave the flavylium salts with cold acids in air. The
flavylium salts were also formed very readily from the hemiketals and acid, and
the trimethoxy- henliketal gave the peltogynidin trimethyl ether cation. In connection with the
mechanism of formation of the hemiketals from chromenoisocoumarins
it was found that 2?-hydroxychalcones are reduced by sodium borohydride to flav-3-enes, and these readily give anthocyanidins when
treated with acid. Parallel biological reduction of chalcones is clearly
possible and a plausible, new, biosynthetic pathway leading directly from 2?-hydroxychalcones
to anthocyanidins and catechins is proposed. Flav-3-enes
are valuable intermediates for preparation of flavans, flavan derivatives, and
flavylium salts, and the new synthesis makes flav-3-enes
readily accessible in one stage from 2?-hydroxychalcones.
Magnetism, electronic spectra, and structure of transition metal alkoxides. V. Copper(II) methoxides
Authors: Adams RW , Barraclough CG , Martin RL , Winter G
Published: September 2010

Najor differences in magnetism are observed in the series CuXL where X = -OMe, Cl, Br, and
L = -OMe, acac. Cu(OMe), exhibits linear antiferro-
magnetism, CuCl(OMe)
follows the Curie law with μeff 2.0 B.M., and CuBr(OMe) is only feebly
paramagnetic. The magnetism of Cu(OMe) acac may be interpreted in terms of a singlet-triplet
equilibrium with -J = 725 cm-1 (2.08 kcal mole-1).
Limitation of cupric bromide for selective side-chain bromination of methyl aryl ketones
Authors: Jemison RW
Published: September 2010

2-Hydroxy-4,6-dimethoxyacetophenone
and its acetate undergo nuclear bromination with cupric
bromide, and 2,3,4-trimethoxyacetophenone gave
w-bromo-2-hydroxy-3,4-dimethoxyacetophenone accompanied by a small yield of
2-hydroxy-3,4-dimethoxyacetophenone and by w-bromo-2,3,4-trimethoxyacetophenone.
Formation of the last compound was shown by isolation of
w-acetoxy-2,3,4-trimethoxyacetophenone after treatment of the mixture of
brominated products with sodium acetate in ethanol.
Acridone studies. III. The formation of aromatic hypobromites from the reaction of melicopine with bromine
Authors: Prager RH , Thredgold HM
Published: September 2010

Evidence is presented that melicopine (1,2-dimethoxy-10-methyl-3,4-methyl-enedioxyacridone)
reacts with bromine in methanol to yield a compound which is formulated as an
aryl dihypobromite. Demethylation of the 1-methoxyl
group occurs, followed by addition of bromine and methanol to the oxygenated
ring. The reactions of this hypobromite are discussed, and several degradation products
synthesized.
The chemistry of the Euphorbiaceae. XVIII. Modified Beyer-15-enes from a Beyeria leschenaultii Var
Authors: Ghisalberti EL , Jefferies PR
Published: September 2010

A variety of Beyeria leschenaultii
has yielded three new diterpenes which have been correlated with beyerol and are shown to be the modified beyer-15-enes (1), (XXXIV), and (XXXVII).
The reaction of 3-0-substituted sugars with aqueous ammonia. 4-(Imidazol-4-yl)butane-1,2,3-triol and its mass spectrum
Authors: Grimmett MR , Hodges R , Richards EL
Published: September 2010

3-Deoxy-D-glucosone,
3-0-methyl-D-glucose, and turanose react with aqueous
ammonia to form L-erythro-4-(imidazol-4-yl)butane-1,2,3-triol
as the major basic product. A mechanism is proposed for the formation of this
imidazole from hexose disaccharides, and its mass
spectrum is discussed.
Copper(II) complexes of glycylglycine and imidazole
Authors: Driver R , Walker WR
Published: September 2010

As a result of an
investigation of copper(11) complexes
containing both glycylglyoine and imidazole, the
following compounds are described for the first time: CuHA(Im)2ClO4,H2O,
Cu2A2Im,8H2O, and CuAIm,H2O (H2A = glycylglycine
= gg, HA = gg-,
A = gg2-, and Im
= imidazole). The complex CuA,3H2O has
also been isolated and used to determine the formation constant of CuA+Im ↔ CuAIm. This has
the value log K = 3.8 � 0.3. The structures of these compounds have been
investigated by physicochemical methods and are discussed.
Oxyanionic complexes of Bis(cyclopentadienyl)titanium(III)
Authors: Coutts RSP , Wailes PC
Published: September 2010

Several oxyanionic
derivatives of bis(cyclopentadienyl)titanium(111)
have been prepared by precipitation from air-free aqueous solutions. Two of
these, (cp2Ti)2SO4
and (cp2Ti)2CO3,
where cp = π-cyclopentadienyl, are described in
detail. Infrared and molecular
weight evidence shows that the sulphato and carbonato ligands are bridging, but whereas the magnetic
susceptibility variation with temperature indicates that the sulphato derivative is magnetically dilute, the carbonato compound shows spin-spin interaction.
Synthetic approaches to mycelianamide
Authors: Brown RFC , Meehan GV
Published: September 2010

Attempts to synthesize the
benzylidene bis-hydroxamic acid system present in mycelianamide (I; R = OH) by
direct carbonyl-methylene condensation were unsuccessful. Nycelianamide
dimethyl ether (XXIV) is a very unstable substance, which lost one N-methoxyl group
as formaldehyde when heated at 77� for 1 hr. Syntheses of compounds closely
related to (XXIV) which depended on the
Nucleophilic square-planar substitutions. II. Substitutions of the bromodiethylenetriamineplatinum(II) complex by pyridine derivatives
Authors: Chan SC , Wong FT
Published: September 2010

The second-order rate
constants for the replacement of coordinated bromide from bromodiethylenetriamineplatinum(11)
bromide by a series of pyridine derivatives have been determined over a range
of temperatures and the Arrhenius parameters
calculated. With the exception of the cyano derivative, replacements of 2-substituted
pyridines are considerably slower than those by the corresponding 3- or
4-substituted nucleophiles. This is explicable on the basis of the associative
mechanism by invoking steric effects of the substituents. The activation
energies for the reaction depend mainly on a combination of two factors, steric
and inductive, with the former predominating. These decrease as the position of
a given substituent in the nucleophile changes in the order 2, 3, and 4. The
inductive effects of the various substituents may be
demonstrated with the 4-substituted pyridines, which are sterically similar to
the unsubstituted pyridine itself. The methyl substitutent has a small effect, while the cyano and chloro
substituents lead to significant increases in activation energy.
A study of some metal gluconates
Authors: Melson GA , Pickering WF
Published: September 2010

The properties of a series
of metal gluconates isolated from acid and alkaline
solution are described. The compounds examined were the simple gluconates of manganese(11), iron(11), zinc(11), cadmium(11),
barium(11), and lead(11), and the complex hydroxy species Cd3(C6H1107)2(OH)4,2H20,
Pb(C6H10O7)2(OH)2,
and Zn2(C6H10O7)(OH)3.
Organomercury compounds. IX. Preparations, structures, and thermal decomposition of arylmercuric arenesulphinates
Authors: Deacon GB , Felder PW
Published: September 2010

The
arylmercuric arenesulphinates, PhHg(SO2Ph), p-MeC6H4Hg(SO2-p-MeC6H4), PhHg(SO2-p-MeC6H4), p-MeC6H4Hg(SO2Ph), and C6F5Hg(SO2Ph), have been prepared by reaction of
mercuric benzenesulphinate or p- toluenesulphinate with the appropriate
diarylmercury compound in chloroform or methanol, and the first three compounds
have also been obtained by reaction of liquid sulphur dioxide with diphenylmercury,
di-p-tolylmercury, or phenyl-p-tolylmercury. Linkage
isomers of phenylmercuric benzenesulphinate have been prepared. Isomer A,
obtained from chloroform-pentane, is considered to be a monomeric O-sulphinato
complex, and isomer B, obtained from cold acetone, methyl ethyI
ketone, or methanol, to be an S-sulphinato complex. The isomers are readily
interconverted. In chloroform, deuterochloroform, and acetone, at room
temperature, only the O-sulphinato complex can be detected. The other
arylmercuric arenesulphinates have the same structure as isomer A. Linkage
isomers could not be isolated for these derivatives. However, there is evidence
that p-MeC6H4Hg(SO2Ph) slowly isomerizes in the solid state to give
the corresponding S-sulphinato complex. Thermal decomposition of PhHg-(SO2Ph) (both
isomers), p-MeC6H4Hg(SO2-p-MeC6H4), PhHg(SO2-p-MeC6H4), and p-MeC8H4Hg(SO2Ph) gives sulphur dioxide and the
corresponding diarylmercurycompound.
Elcteocarpus alkaloids. III. The structure of elaeocarpidine, a new indole alkaloid
Authors: Johns SR , Lamberton JA , Sioumis AA
Published: September 2010

Elaeocarpidine, C17H21N3,
a new alkaloid from Elaeocarpus densiJorus
Knuth.� has been shown to be (I). A trans configuration is preferred for both
the C/D and D/E ring junctions.
Sulphur-nitrogen chelating agents. VI. Five- and six-coordinate complexes of 3d metal ions with an SNN tridentate ligand
Authors: Chia PSK , Livinhstone SE
Published: September 2010

Mono-ligand complexes of
6-methylpyrid-2-yl-N-(2?-methylthiophenyl)- methyleneimine
(SNSMe) of the type MX2(SNNMe) (M = Mn, Fe, Co, Xi, and
Cu; X = Cl, Br, I, or NCS) have been prepared.
Infrared data show that in all the complexes the ligand (SNNMe)
is tridentate. The electronic and infrared spectra indicate that the complexes
of manganese, iron, and cobalt are five-coordinate, whereas the nickel and
copper complexes are six-coordinate and polymeric. The complex CO(NO3)2(SNNMe) is six- coordinate and contains one bidentate and
one unidentate nitrato group. ��� The bis-ligand complexes [N(SNNMe)2]Y2 (M = Fe, Ni, and Cu; Y = ClO4 or BF4) were also isolated. The
iron complex is low-spin (μ 1.5 B.M.) but the magnetic moment of the
nickel complex (μ 3.0 B.M.) is normal for high-spin octahedral nickel(II).
The Diels-Alder reaction of some styrenes and 2,2-dimethylchromenes with acetylenic esters
Authors: Diment JA , Ritchie E , Taylor WC
Published: September 2010

Examples of the Diels-Alder
reaction between some derivatives of styrene and of 2,2-dimethylchromene and
dimethyl acetylenedicarboxylate and methyl propiolate, leading ultimately to
fully aromatic derivatives, are described. Yields are generally low and the
synthesis has limited utility. However, the n.m.r, spectrum of the product from
acronycine dimethyl acetylenedicarboxylate is such as to establish the angular
rather than the linear structure for acronycine.
The alkaloids of Crotalaria grahamiana. Grahamine, the 3'-[( - )-2-methylbutyryl] ester of monocrotaline
Authors: Atal CK , Culvenor CCJ , Sawhney RS , Smith LW
Published: September 2010

The seed of Crotalaria grahamiana R. Wight & Walk.-Arn.
contains mono- crotaline and a new alkaloid, grahamine, which is a 3?-[(-)-2- methylbutyryl]
derivative of monocrotaline. ��
Enzymatic transamination: The synthesis of α,β,β-Trideutero-L-glutamic acid and α-Dentero-L-glutamic acid
Authors: Whelan DJ , Long GJ
Published: September 2010

α,β,β-Trideutero-L-glutamic acid has been synthesized by incubating L- glutamic
acid in D2O at pD 7.8 in the presence of
pig-heart glutamate- oxaloacetate aminotransferase and catalytic amounts of
pyridoxal 5?- phosphate and oxaloacetic acid. However, when L-glutamic acid is
incubated under similar conditions with pig-heart glutamate-pyruvate
aminotransferase, in the presence of catalytic amounts of pyridoxal 5?-
phosphate and pyruvic acid, α-deutero-L-glutamic acid is obtained.
The reaction of 1,1-Dichloro-2,2-di(p-chlorophenyl)ethane (DDD) with sodium thiophenoxide in ethanol
Authors: McLennan DJ
Published: September 2010

The reaction of
1,1-dichloro-2,2-di(p-chlorophenyl)ethane (DDD) with
sodium thiophenoxide in ethanol yields the unexpected product Ar2C=CHSPh (Ar = p-ClC6H4)
by a second-order process. Elimination-addition- decomposition; elimination-substitution;
and direct disubstitution- decomposition mechanisms have been considered. The
absence of a β- deuterium isotope effect in the reaction (contrasted with
kH/kD = 4.6 for the E2 elimination using sodium ethoxide
as the base) argues for direct SN2 substitution of both aliphatic
chlorines of DDD followed by decomposition of Ar2CHCH(SPh)2 (which was not detected) to the observed
product and thiophenol.
Luminescence and triplet energy transfer in mixed crystals. I. Two-component systems
Authors: Adam KR , O'Dwyer MF
Published: September 2010

Quantitative results are
given for the temperature dependence of the intensities and decays of
phosphorescence and delayed fluorescence in a number of two-component organic
mixed crystals. These results are interpreted in terms of a kinetic model. For
low guest concentrations, the guest phosphorescence decay is found to be first
order and strongly temperature dependent with an activation energy different
from that involved in energy transfer to the host triplet exciton level.
Luminescence and triplet energy transfer in mixed crystals. II. Three component systems
Authors: Adam KR , O'Dwyer MF
Published: September 2010

Triplet-triplet energy
transfer between two guest molecules in a host crystal has been studied by
observing the temperature and concentration dependence of the phosphorescence
of the donor guest molecule. The results are interpreted in terms of transfer
via the host triplet exciton band.
A synthesis of the juvenile hormone, methyl cis-10,11-Epoxy-7-ethyl-3,11-dimethyltrideca-trans-2,trans-6-dienoate
Authors: Cavill GWK , Laing DG , Williams PJ
Published: September 2010

Methyl
(�)-cis-10,11-epoxy-7-ethyl-3,11-dimethyltrideca-trans-2,trans-
6-dien-oate (I) has been synthesized via 6,7-isopropylidenedioxy-7-
methylnonan-3-one. The route is also applicable to the synthesis of homologues
and analogues.
Diterpenoids. XXII. The C8 stereochemistry of 'manool trihydrochloride' and other halogenated labdanes
Authors: Carman RM , Deeth HC
Published: September 2010

The stereochemistry of
?manool trihydrochloride? has been revised at C8. The stereochemistry of the
reaction between hydrogen chloride and some 1-hydroxy- 1-methyl substituted
cyclohexanes has been investigated.
The hydroxyl stretching frequencies and conformations of Flavan-4-ols and Thiaflavan-4-ols
Authors: Katekar GF , Moritz AG
Published: September 2010

The hydroxyl stretching
frequencies of some 2,4-cis and 2,4-trans flavan-4-ols, thiaflavan-4-ols, and
related compounds have been measured in dilute carbon tetrachloride solution.
Characteristic frequencies are observed at 3626�2 cm-1 (free hydroxyl),
3616�1, and 3597�2 cm-1. The 3616 and 3597 cm-1 bands are
assigned to pseudo-axial and pseudo-equatorial hydroxyl groups respectively.
Evidence is presented to show that the frequency shifts arise from differences
in the interaction of the hydroxyl group with the π-electrons of the fused
benzene ring, and that these flavans and thiaflavans exist in half- chair,
rather than sofa conformations.
Base hydrolysis of trans-Halogenoamminebis(dimethylglyoximato) (III). Complexes
Authors: Chan SC , Leung PY
Published: September 2010

The disappearance of
trans-[Co(LH)2(NH3)X] (LH = dimethylglyoximate ion, X =
chloride or bromide) has been studied in aqueous solutions over a range of
alkali concentrations at various temperatures. The kinetics were done with
excess of hydroxide ion at a constant ionic strength so that pseudo first-order
rate constants were obtained in all the runs. The results were interpreted in
terms of the rapid formation of a pre- equilibrium species which then reacts in
a rate-determining step to give products. The relatively large equilibrium
constants support a conjugate-base pre-equilibrium, in which the proton is lost
from oxygen, while the relatively low reactivities of the conjugate-bases are
consistent with the absence of electropositive electromeric effects. The
similarity in the reactivities of the chloro and the bromo conjugate-bases suggests
the possibility of an SN2CB mechanism.
Ring strain and the negative pole. II. The interaction of strained rings with an adjacent ionic charge
Authors: Miller IJ
Published: September 2010

Using the technique
previously developed, the energies of interaction of strained ring substituted carbonium ions are calculated. The calculated values are in
good agreement with experimentally determined results, and are self-consistent
with the strain energies and dipole moments calculated in Part I. the
The thermal decomposition of trimethylacetyl bromide
Authors: Lennon BS , Stimson VR
Published: September 2010

Trimethylacetyl bromide decomposes at 298-364� into isobutene,
carbon monoxide, and hydrogen
bromide in a first-order manner with rate given by

k1 = 138 x 1014exp(-48920/RT)
sec-1

The rate is unaffected by
addition of the products or of inhibitors, or by increase of the surface/volume
ratio of the reaction vessel. The likely radical chain mechanism is considered
and rejected. The reaction is believed to be a molecular one, and possible
cyclic and polar transition states are discussed.
A stereospecific synthesis of trisubstituted double bonds
Authors: Birch AJ , McKague B
Published: September 2010

An aspect of the synthesis
of sterically defined trisubstituted double bonds is
discussed. Metal-ammonia reductions of hydropyridinium
salts such as (1 ; R, R' = H or Me) result in allylic
fissions, with a considerable proportion of double bond retention in its
original situation and complete retention of the original steric configuration
in that position.
Excess volumes of dimethyl sulphoxide mixtures
Authors: Lau CF , Wilson PT , Fenby DV
Published: September 2010

The volumes of mixing
(excess volumes) for dimethyl sulphoxide with carbon tetrachloride,
chloroform, benzene, acetone, and water have been measured at 25.00� and 35.00�
with a dilatometer. The values for the equimolar mixtures at 25.000 are -0.596,
-0.112, -0.304, -0.511, and -0.944 cm3 mol-1
respectively. The results are compared with available density measurements on
these systems and qualitatively compared with the corresponding acetone
systems.
Theory of super-regenerative detection of N.Q.R.
Authors: Caldwell RA , Hacobian S
Published: September 2010

Signal intensities of the 35Cl nuclear quadrupole transition in
para-dichlorobenzene, obtained using a frequency modulated superregenerative
spectrometer, are investigated as a function of quenching frequency. The
quenching voltage is applied in the form of pulses of variable on (ton)
and off (toff) times. A method is provided
for the calculation of (Vs2/Vn2)�
which appears in the detection equation

ΔA = aV0In(1 + Vs2/Vn2)�

By applying the theory of
nuclear induction to a series of pulses, such as those of a super-regenerative
oscillator, it is possible to explain the observed behaviour of signal
intensities with operational characteristics and solid state relaxation
parameters.
Dependence of the frequencies of intermolecular vibrations of associated water molecules upon the size of the association complexes
Authors: Vetrov AA , Shelyukhaev BP
Published: September 2010

The intermolecular
vibration frequencies for associated water molecules have been calculated by
the Elyashevich-Wilson technique. Slight variations
of the geometric parameters of the water molecules and hydrogen bridges leave
the intermolecular vibration frequencies almost unaffected. The values of these
frequencies depend solely upon the force constants of the hydrogen bonds and
the angles adjacent to a hydrogen bond. The spectra of associations containing
two, three, four, and five water molecules are found to be sufficiently
distinct from each other for their differences to be detected by experiment.
Dimers of α,β-substituted styrenes: Tetralin derivatives from reaction of 1-(p-Chlorophenyl) -2,2-dimethylpropan-1-ol with sulphuric acid
Authors: Brophy GC , Collins DJ , Hobbs JJ , Sternhell S
Published: September 2010

Two compounds, m.p. 129-130�
and 169-170�, obtained from reaction of 1-(p-chlorophenyl)-2,2-dimethylpropan-1-ol or from 2-(p-chlorophenyl)-3-methylbut-2-ene with sulphuric acid, have been shown to be
the diastereoisomers of 7-ohloro-3-(p-chlorophenyl)- 1 -isopropyl- 1,4,4-trimethyltetralin
(6a). Reaction of mono- and di-methyl-p-chlorostyrenea with sulphuric acid under the
same conditions gave mainly indane derivatives.
Products were separated by fractional crystallization, and preparative gas
chromatography. Structures of pure compounds were assigned mainly on the basis
of n.m.r, spectroscopy.
A synthesis of acronycine
Authors: Hlubucek J , Ritchie E , Taylor WC
Published: September 2010

Improved syntheses of
certain O-and N-methyl derivatives of 1,3-dihydroxy-acridone
are described. Thermal rearrangement of the appropriate 3-α,α-dimethyl-propargyl
ethers in the series yields products which may be methylated to acronycine.
Fluorine-19 substituent chemical shifts (SCS)
Authors: Adcock W , Bettess PD , Rizvi SQA
Published: September 2010

A number of substituted
aryl fluorides have been synthesized and their fluorine-19 substituent
chemical shifts (scs) have been measured. The comparison of the scs of 1-(m-fluorophenyl)propan-2-one, 1-(p-fluorophenyl)propan-2-one, 7-fluorotetral-2-one,
and 6-fluorotetral-2-one confirm Dewarsl-3
conclusions that long-range non-mesomeric effects are
transmitted through space and that this polar effect makes a considerable
contribution to the overall 19F scs in aromatic systems. It is also shown that the
fluorine substituent chemical shifts of +F+M substituents in 7-substituted 2-fluoronaphthalenes (7β) can be interpreted in terms of
a modified FM treatment. The mesomeric-field effect
is shown to be important in this disposition (78) of naphthalene.
N.M.R. studies of aqua exchange on trimethylaquabipyridineplatinum(IV)
Authors: Clegg DE , Hall JR , Ham NS
Published: September 2010

Proton magnetic resonance
spectroscopy has been used to study the exchange reaction which is responsible
in aqueous solution for averaging the two methyl proton signals of trimethylaquabipyridineplatinum(1V) cation. The dependence
of the rate upon cation concentration, pH, added sulphate
ion, and temperature and the appearance of 195Pt satellites in the 2,2'-bipyridine
proton spectrum lead to the conclusion that the reaction being followed is
exchange of a coordinated water ligand with the bulk solvent.
The adsorption of dyes on zinc oxide: The effect of non-stoicheiometry
Authors: Norman VJ
Published: September 2010

The adsorption of uranine and rhodamine B, from both aqueous and alcoholic solutions, on to high-purity zinc oxide has been determined, and the results compared with the adsorption on zinc oxide powders having a wide range of non-stoicheiometric composition induced by doping with monovalent and trivalent cations.
It is shown that, from aqueous solution, total adsorption of the acid dye uranine on undoped zinc oxide comprises approximately 10% chemisorption, and 90% adsorption of lower energy. Both chemisorption and lower energy adsorption were markedly increased when the zinc oxide was made more strongly n-type by doping with aluminium. Doping with lithium to produce an electron deficiency resulted in a reduction of both types of adsorption to approximately one-half of their original value. From alcoholic solution, only chemisorption is affected by the non-stoicheiometry of the zinc oxide. It is suggested that the lower energy adsorption from alcoholic solution is true physisorption, and that from aqueous solution is a weak type of chemisorption by electrostatic forces.
Adsorption of the basic dye rhodamine B, from both aqueous and alcoholic solutions, on to surfaces of doped and undoped zinc oxide is exclusively chemisorption. The chemisorption is increased by doping with lithium, and decreased by aluminium doping.
Dark conduction through anthracene crystals
Authors: Johnston GR , Lyons LE
Published: September 2010

Dark currents through anthracene crystals with silver paste electrodes were studied as functions of temperature, applied voltage, and time. Activation energies between 0.5 eV and 2.9 eV were measured, there being a definite correlation between log �0 and E (the compensation effect'). However, it was shown that the compensation effect arises from the calculation of �0 and E, and not from a true linear free-energy relationship. As simple carrier generation mechanisms were inadequate to explain the temperature-dependence results, a model involving transitions between two limiting mechanisms was invoked and developed. The voltage-dependence results are shown to arise by a transition from SCL currents at low voltages, to barrier-limited currents (BLC) at higher fields, where the Schottky effect controls the current-voltage response. Vindication of the choice of this model is obtained from the calculated values of the parameters �, the permittivity of anthracene; A, the Richardson constant; �, the surface energy barrier for hole injection from silver paste into anthracene; and WE(Ag), the work function for silver paste electrodes.
The chemistry of pyrrolic compounds. XII. Dipyrrylmethanes
Authors: Clezy PS , Liepa AJ
Published: September 2010

The synthesis of a range of dipyrrylmethanes, substituted with electrophilic substituents at one or more �-positions, is described. Bromine vapour has been found to be a useful reagent for identifying dipyrrylmethanes on thin-layer plates.
New alkaloids of Alstonia constricta
Authors: Crow WD , Hancox NC , Johns SR , Lamberton JA
Published: September 2010

In the course of the isolation of reserpine from the tertiary alkaloids of Alstonia constricta root bark, a number of other alkaloids were obtained, and these alkaloids have now been the subject of further study. Alstonidine, a previously known alkaloid for which the provisional structure (6) was suggested, has now been shown to have the stereochemistry depicted in (7a). A new alkaloid, alstonilidine, has been shown to be (8). Vincamajine (9) has been identified, and two new alkaloids, O-3,4,5-trimethoxycinnamoylvincamajine (10) and 0-3,4,5-trimethoxybenzoylquebrachidine (11) have been isolated from the "reserpine concentrate". Another alkaloid, probably C43H50N4O7, appears to be a new member of the "bisindole" group.
An electron spin resonance study of the copper(II) complexes of Tris(hydroxymethyl) aminomethane formed in aqueous and non-aqueous solution
Authors: Boyd PDW , Pilbrow JR , Smith TD
Published: September 2010

The electron spin resonance
spectra of copper(II)- tris(hydroxymethyl)amino-methane complexes in aqueous
solution provides evidence of the formation of dimeric species. These species
are found to be different from those postulated by previous investigations. In
dimethylformamide dimeric species are formed at room temperature and frozen
solution in 1 : 1 and 1 : 2 metal-to-ligand mole ratios, though the formation
of the dimer is critically dependent on the addition of base. Low field, ΔM
= 2, signals observed for these systems have been interpreted in terms of
dipole-dipole coupling between pairs of copper(II) ions. Structures for the
copper(II) dimers have been proposed which are compatible with the
copper-copper separation estimated by computer simulation of the spectra.
Diffusion coefficients of some azo dyes
Authors: Craven BR , Datyner A , Kennedy JG
Published: September 2010

A comparison of diffusion coefficients of a series of four azo dyes
determined in stirred and unstirred glass membrane cells has indicated that the
presence of a stagnant layer in an unstirred cell gives rise to a considerable
error at lower temperatures, but the error decreases with increasing
temperature.
The formation constants of some metal complexes with 3-Acetyl-4-hydroxycoumarin, dehydroacetic acid, and their oximes
Authors: Manku GCS
Published: September 2010

The formation constants (K1,
K2, and β2) of the complexes of 3-acetyl-4-
hydroxycoumarin (ahc) and dehydroacetic acid (dha) and their respective oximes, ahco
and dhao, with iron(II), cobalt(II), nickel(II),
copper(II), zinc(II), calcium(II), magnesium(II), cadmium(II), dioxouranium(VI), iron(III), aluminium(III), scandium(III),
indium(III), yttrium(III), and lanthanon(III) ions (lanthanum to lutetium
inclusive with the exception of promethium) have been determined pH-metrically at
35� in 50% v/v aqueous dioxan medium with 0.100M sodium perchlorate as the
constant ionic concentration, using Calvin and Wilson's pH-metric technique.
The trends in the formation constants of these complexes are discussed. It is
observed that, except in the case of Co2+,
Ni2+, and Cu2+
ions, for which chelation through nitrogen donors is more favoured, all other
ions prefer coordination through oxygen donors.
Carbonyl halides of the Group VI transition metals. XXIII. An N.M.R. study of a series of Bis(diphenylarsino)methane derivatives of molybdenum(II) and tungsten(II)
Authors: Anker MW , Colton R , Rix CJ
Published: September 2010

A variable temperature
nuclear magnetic resonance study of a series of molybdenum(II) and tungsten(II)
complexes of the general formula M(CO)2(dam)2X2 (M = Mo,
W; X = Cl, Br, I; dam = bis(diphenylarsino)methane)
has been carried out. These compounds have previously been shown to be
seven-coordinate non-electrolytes containing one chelated and one monodentate
dam ligand. The detailed study of their N.M.R. spectra reported here shows
that, near room temperature, exchange occurs between the non-equivalent dam molecules.
At lower temperatures this exchange ceases, but further fine structure appears
in the spectra due to the freezing-in of particular conformation of the
molecules. On warming, this fine structure disappears as a result of the
inherent non-rigid character of the ligand. ��� The experimental spectra have been compared
with a set of computed spectra based on the model of an exchanging system to
determine the various exchange rate constants, and the observed spectra have
been interpreted m terms of the molecular stereochemistry about the metal.
Photochemical redox reactions at the zinc oxide-water interface in additive-free systems
Authors: Dixon DR , Healy TW
Published: September 2010

When aqueous ZnO
suspensions, saturated with oxygen, are irradiated with u.v. light, hydrogen
peroxide is formed and a decrease in pH is observed. The effects of different
gases (O2, N2, and N2O) on the course of this
heterogeneous reaction and also the pH dependence of the reaction have been
examined. On the basis of the results obtained, the mechanism which had been
previously suggested was modified to allow for the hydrolysis of the zinc(II)
ions removed from the crystal lattice during irradiation. A general reaction
mechanism proposed to account for H2O2 production in
systems with various additives present is extended to additive-free systems
where interstitial zinc (Zn1+) is the effective
reductant.
Oxidation of carbohydrates with chromium trioxide in acetic acid. II. Acetals. A new synthesis of ketoses
Authors: Angyal SJ , James K
Published: September 2010

Oxidation of fully acylated
methylene and benzylidene acetals of alditols with chromium trioxide in acetic
acid yields fully acylated ketoses in their keto form. Derivatives of hex-3-uloses
have been prepared by this method. Syntheses of 3,4-O-methylene-D-mannitol and
3,4-O-methylene-D-glucitol are described.
The vibrational spectra and structure of the Bis(hexamethylenetetramine)iodine(I) cation
Authors: Bowmaker GA , Hannan SF
Published: September 2010

The crystalline compound
reported in the literature as the 1 : 1 addition complex of
hexamethylenetetramine (hx) with iodine is shown by
means of i.r. and Raman spectroscopy to be an ionic
compound consisting of bis(hexamethyl-enetetramine)iodine(I) ions, (hx)2I+, and I3-
ions. A crystalline compound consisting of molecules of the true 1 : 1 addition
complex (hx)I2 does exist, however, and
its preparation is described. On standing, this compound undergoes an unusual
solid state transformation, resulting in the formation of the ionic complex.
The (hx)2I+ ion is the first
documented example of a bis(amine)halogen(I) ion involving an amine other than
pyridine or its derivatives. A structure for this ion is proposed in which the
hexamethylenetetramine molecules are bound to the iodine atom through one of
their nitrogen atoms, the resulting N...I...N arrangement being linear,
centrosymmetric, and lying along the threefold axis passing through the
coordinated nitrogen atom of each hexamethylenetetramine molecule. The evidence
for this structure obtainable from the vibrational spectra of the ion is
discussed. A preliminary investigation of the valence force field indicates
unusually strong nitrogen-iodine bonding in this ion. The literature method for
preparing bis-(pyridine)halogen(I) perchlorates has been modified and used to
prepare the perchlorate of bis(hexamethylenetetramine)iodine(I).
Magnetic properties of some tridentate Schiff-base-manganese(II) complexes
Authors: Butler KD , Murray KS , West BO
Published: September 2010

A series of manganese(II)
chelates of stoicheiometry [MnL] have been synthesized, where LH2 is
a dibasic tridenate Schiff base formed between a 5-substituted salicylaldehyde
and either a 5-substituted β- hydroxyaniline or anthranilic acid. The
complexes are extremely susceptible to oxidation in solution but stable when
dry. Some of the complexes were isolated as hemihydrates and others as mixed
hydrate- ethanolates. Magnetic susceptibility measurements over the temperature
range 80-300�K have been made for a number of the complexes. In some cases the
magnetic moments at room temperature are reduced slightly from the spin-only S
= 5/2 value and show θ values of c. 15-50�K. The results can be
interpreted in terms of binuclear or polynuclear structures with very small
values of the exchange integral J. Comparisons between observed and calculated
data are not as good as those shown in related VO2+, NiII,
CuII, and FeIII systems for which X-ray crystal
structures are known.
Substituted carbonyl derivatives of the Group VI transition metals. II. Complexes with tritolylphosphines
Authors: Bowden JA , Colton R
Published: September 2010

The reactions of the three
tritolylphosphines (ortho, meta, and para) with the metal hexacarbonyls, M(CO)6
(M = Cr, Mo, W), have been investigated under a variety of conditions of
temperature, ultraviolet irradiation, and molar ratio. The products were of the
general formulae M(CO)5L and cis and trans M(CO)4L2
[L = tri-tolylphosphine] although not all the tetracarbonyl complexes could be
prepared. Infrared and nuclear magnetic resonance spectra of these compounds
showed interesting trends as the ligand was varied. ��� In addition, a novel series of derivatives
with tri(o- tolyl)phosphine (pot) has been isolated, which on the basis of
infrared, N.M.R., and mass spectral data are formulated as π- (pot)M(CO)3.
��� The nature of the above reactions and the
properties of the products are explained in terms of an argument based on
steric effects.
Oxidation of alkyl thiocyanates by peroxomonosulphate in acidic aqueous solution
Authors: Bridgart GJ , Wilson IR
Published: September 2010

Studies of the rates and
mechanisms of oxidation of four alkyl thiocyanates by peroxomonosulphate are
reported, Analysis of the data is consistent with the occurrence of two
consecutive reaction steps of comparable rate coefficient. The product of the
second step appears to be the sulphonyl cyanide, RSO2CN.
Kinetics of the hydrolysis of acetic anhydride in concentrated salt solutions
Authors: Oakenfull DG
Published: September 2010

The kinetics of the
hydrolysis of acetic anhydride have been investigated in concentrated salt
solutions at 20�. Sine salts were used in concentrations of up to 5 mol 1-1;
all inhibited the reaction. ��� The salt effect was resolved into its
component effects on the reactants and the transition state by use of the Bronsted-Bjerrum
equation to calculate transition state activity coefficients from rate
constants and measured activity coefficients of acetic anhydride. The effect of
a salt on the free energy of the reactants was always significant and in some
cases it was the major component of the effect of the salt on the free energy
of activation. The enthalpy and entropy of transfer from water to 1 mol l-1
sodium chloride, for both acetic anhydride and the transition state, show the
enthalpy-entropy compensation effect which is typical of aqueous solutions. ��� These salt effects are considered to be
part of the general phenomenon of the effect of salts on the activity
coefficients of non-electrolytes. The inhibition is not caused by formation of
a complex between salt and acetic anhydride. Rate constants could not be
correlated with dielectric constant and ionic strength, using Gold's equation,
and changes in water structure which occur in these salt solutions were shown
to have no direct effect on the reaction rate.
The constituents of Olearia heterocarpa. The structure of olearin, a diterpene dilactone of the cascarillin group
Authors: Pinhey JT , Simpson RF , Batey IL
Published: September 2010

Chloroform extraction of
Olearia heterocarpa S. T. Blake has yielded a new diterpene dilactone, olearin,
the known flavone, xanthomicrol, an unknown C27H42O3
hydroxy acid, and a mixture of long-chain (approx. C50) esters. On
chemical and spectroscopic evidence olearin (1) has been shown to possess a
rearranged enantio-labdane skeleton of the type displayed by the cascarillins.
Correlation of olearin with a diterpene of known stereochemistry has defined
the absolute con- figuration at all but one centre.
The oxidation of methyl acetylbetulate and methyl acetylmelaleucate by mercuric acetate
Authors: Baddeley GVSJJH , Watson TG
Published: September 2010

The oxidation of methyl
acetylbetulate by mercuric acetate to give methyl 3β-acetoxylupa-18,20(29)-dien-28-oate
has been confirmed by further degradations of the dihydro derivative, methyl
3β-acetoxylup- 18-en-28-oate. The oxidation of
methyl acetylmelaleucate by mercuric acetate similarly introduces Δ18-unsaturation.
The structures of melaleucic acid, ceanothenic acid, and emmolactone are
discussed.
The preparation and some reactions of symmetrical Dichloro-1,3,5-triazine derivatives of polyethylene glycols
Authors: Ayscough FW , Simpson IN
Published: September 2010

The preparation is described
of the bis(dichlorotriazinyl) derivatives of diethylene and triethylene glycol
and of the bis(chlorobutylaminotriazinyl), bis(chlorobutylthiotriazinyl), and
bis(chlorophenoxytriazinyl) derivatives of diethylene glycol. In addition,
there is described the preparation of a water-soluble bis(dichlorotriazinyl)
derivative of a polyethylene glycol and evidence is produced for its reactions
with glycine, γ-aminobutyric acid, N- acetylcysteine, glutathione, and
tyrosine.
The diterpenes of Dacrydium kirkii. A synthesis of Labdane-7α,13-diol
Authors: Grant PK , Huntrakul C , Weavers RT
Published: September 2010

The tetrahydro
derivative of the naturally occurring diterpene, 7α-hydroxy-manool, has
been synthesized using allylic bromination and allylic acetoxylation methods.
The structures of other reaction products were elucidated.
Acridone studies. IX. Reaction of the isomeric Bromo-10-methylacridones with potassamide, lithium piperidide, and piperidine
Authors: Gream GE , Hodgeman DKC , Prager RH
Published: September 2010

The reaction of the four
isomeric bromo-10.methylacridones with potassamide
and lithium piperidide has been studied, and the
products rationalized in terms of the addition-elimination and
elimination-addition mechanisms. The 1-bromo isomer reacts anomalously with potassamide, giving a Haller-Bauer type product. Reduction competes with
substitution in the reaction of 2- and 4-bromoacridones with lithium piperidide.
Anomalous magnetism of iron(II) complexes of methyl-substituted pyridylthiazoles
Authors: Goodwin HA , Mather DW
Published: September 2010

Bis-ligand iron(11) and
nickel(11) complexes of the potentially tridentate chelating agents
2-(3-methyl-2-pyridylamino)-4-(2-pyridyl)thiazole and 2-(4-methyl- 2-pyridylamino)-4-(2-pyridyl)thiazole
are described. The electronic spectra of the nickel(11) complexes show that the
field strengths of the ligands are in the neighbourhood
of the Crossover region for iron(11). The magnetic properties of the cationic
iron(11) complexes are anomalous and consistent with a spin-equilibrium
involving the nearly equi-energetic 5T2
and 1A1 states of the metal atom. The magnetism shows a
strong dependence on the associated anion. 2-(6-Methyl-2-pyridylamino)-4-
(2-pyridyl)thiazole is also described. In its bis-ligand iron(11) complexes it
functions as a bidentate chelating agent and the complexes are high-spin. All
three ligands may be deprotonated to yield inner complexes with iron(11) which
in some instances have anomalous magnetic properties associated with the
presence of a spin-equilibrium. 2-(6-Methyl-2-pyridyl)-4-(2-pyridyl)thiaole and its bis-ligand iron(11) and nickel(11)
complexes are also described. The iron(11) complexes are high-spin and show
normal temperature dependence of their magnetism.
Equilibria involving allylbenzene, chloride ion, and palladium(II) in acetic acid solution
Authors: Cruikshank BI , Davies NR
Published: September 2010

The addition of allylbenzene to sodium di-μ-chloro-tetrachlorodipalladate(11)
in acetic acid solution produces changes in the absorption spectrum which are
compared with those produced by chloride ion and by pyridine. The occurrence
and disappearance of certain isosbestic points over
various ranges of ligand to palladium ratios together with evidence from plots
of absorbance against mole ratio indicates that
complex formation occurs in discrete steps. Evidence is presented which
supports the view that under the conditions normally employed for the
homogeneous catalytic isomerization of alkenes, the palladium is present as a
monomeric palladium-alkene complex.
The vibrational spectra and structure of the 1 : 1 hexamethylenetetraminebromine complex
Authors: Bowmaker GA , Hannan SF
Published: September 2010

The i.r.
and Raman spectra of the crystalline 1 : 1 complex of hexamethylenetetramine (hx) with bromine have been obtained, and these suggest that
the solid consists entirely of (hx)2Br+
and Br3- ions. A structure similar to that found for other
bis(amine)halogen(r) ions is proposed for the previously unreported (hx)2Br+ ion, and a method is given
for the preparation of its perchlorate. The i.r.
spectrum of this compound, and that of the I
: 2 hx-bromine complex, have also been obtained, and
these support the proposed ionic structure for the 1 : 1 complex.
Transition metal complexes of substituted alkynes. IX. Factors that influence the formation of Tris(alkyne)cobalt complexes
Authors: Dickson RS , Fraser PJ
Published: September 2010

Reactions involving p-alkyne-hexacarbonyldioobalt complexes and an
excess of an alkyne have been investigated systematically to determine some of the
factors affecting the formation and stabilization of CO,(CO)~C,(CF,)~R,-, complexes.
Systems have been studied in which the value of n has been varied through all values
from 0 to 6.
The new tris(a1kyne)tetracarbonyldioobalt complex CO,(CO),C,(CF,),(CH~)~-
Hz, formed from Co,(CO),(CH,C,CH,) and an excess of CF,C=_CH, has been
characterized by elementary and spectroscopic analysis. Tris(a1kyne)tetracarbonyldi-
cobalt compIexes have not been isolated from the systems [Co,(CO),(CF3C,CF3)+2-
CH,C=CCH,], [Co,(CO),(CF,C,CF,) + 2CH3CzCH], [Co,(CO),(CF,C,CH,) + 2CH3C~C-
CH,], [Co,(CO),(CH,C,CH,) + 2CF3CKXF3], [Co,(CO),(CH3C,CH,) + 2CH3C~CCH3],
and [Co,(CO),(CH3C,CH,)+2CH3C~CH]. Rather, significant amounts of various
CF,- and/or CH,-substituted benzenes are obtained in these reactions. These sub-
stituted benzenes are presumably formed by decomposition of unstable tris(a1kyne)-
tetracarbonyldicobalt complexes.
The accumulated results indicate that two principal factors influence the
stability of the CO,(CO)~C,(CF,),R,-, complexes. Stable complexes are isolated only
when (i) at least two CF, groups are incorporated as substituents in the C,-bridging
fragment, and (ii) CF, substituents are attached to the two terminal carbon atoms of
the bridging fragment.
VIVID interacts with the WHITE COLLAR complex and FREQUENCY-interacting RNA helicase to alter light and clock responses in Neurospora
Authors: Hunt Suzanne M. , Thompson Seona , Elvin Mark , Heintzen Christian
Published: September 2010

The photoreceptor and PAS/LOV protein VIVID (VVD) modulates blue-light signaling and influences light and temperature responses of the circadian clock in
Neurospora crassa
. One of the main actions of VVD on the circadian clock is to influence circadian clock phase by regulating levels of the transcripts encoded by the central clock gene
frequency
(
frq
). How this regulation is achieved is unknown. Here we show that VVD interacts with complexes central for circadian clock and blue-light signaling, namely the WHITE-COLLAR complex (WCC) and FREQUENCY-interacting RNA helicase (FRH), a component that complexes with FRQ to mediate negative feedback control in Neurospora. VVD interacts with FRH in the absence of WCC and FRQ but does not seem to control the exosome-mediated negative feedback loop. Instead, VVD acts to modulate the transcriptional activity of the WCC.
Determination of Gross Chromosomal Rearrangement Rates
Authors: Putnam Christopher D. , Kolodner Richard D.
Published: September 2010

INTRODUCTION

Cells devote a significant amount of metabolism to maintaining the stability of their genome and to preventing inappropriate chromosomal rearrangements that are characteristic of many cancers. A simple genetic assay using haploid derivatives of the yeast Saccharomyces cerevisiae provides a means to quantitatively measure the rate at which gross chromosomal rearrangements (GCRs) accumulate in different genetic backgrounds. This assay measures the rate of simultaneous inactivation of CAN1 and URA3 markers placed on a nonessential end of a yeast chromosome and in principle can be implemented in any haploid strain. Rearrangements detected with this assay include broken chromosomes healed by de novo telomere additions and a spectrum of inter- and intrachromosomal fusion events. The GCR assay allows for detailed analysis of the contributions of individual genes and different pathways in the suppression of genomic instability.