bluuebunny/crossref_metadata_2025 huggingface dataset:
Confirmation of the Hybrid Origin of Chiloglottis × pescottiana (Orchidaceae: Diurideae). I. Genetic and Morphometric Evidence
Authors: Peakall Rod , Bower C. C. , Logan A. E. , Nicol H. I.
Published: August 2004

Pollination by sexual deception in orchids is characterised by a high degree
of pollinator specificity, which may account for the rarity of natural hybrids
within the group. Only one such hybrid has been formally recognised in
Australia, Chiloglottis ×
pescottiana R.S.Rogers, which has intermediate floral
morphology between its putative parents, C. valida
D.L.Jones and C. trapeziformis Fitzg. In this paper,
genetic and morphometric analyses confirm the hybrid origin of this taxon.
Allozyme analysis of C. trapeziformis and
C. valida revealed fixed allelic differences at four
‘diagnostic’ loci and significant frequency differences at three
other loci. In all cases, C. ×
pescottiana exhibited fixed heterozygosity at the
diagnostic loci. Multidimensional scaling of both the genetic data and seven
morphometric traits revealed distinct clusters of
C. trapeziformis and C. valida
while C. × pescottiana
formed an intermediate cluster between the two parents. To test for genetic
compatibility between C. trapeziformis,
C. valida and C. ×
pescottiana, a series of reciprocal artificial crosses
were performed. In all cases, the percentage of capsules formed was at least
as great for between-species crosses as for within-species selfs and crosses
(range 75–100%). No significant differences in the percentage of
seed with normal embryos was detected between self- and cross-pollinations
within C. trapeziformis (range 77–81%),
C. valida (range 59–74%) and
C. × pescottiana (range
30–51%), but the percentage of normal embryos was notably lower
in C. × pescottiana. The
cross C. trapeziformis female by
C. valida male produced significantly more normal
embryos (90%) compared with the reverse cross (46%). Artificial
backcrosses of C. ×
pescottiana to C. valida and
C. trapeziformis had lower percentages of normal embryos
when C. × pescottiana was
the pollen donor (39–43%) rather than recipient
(62–68%), suggesting reduced pollen viability in the latter
taxon. The size of F2 embryos in C. ×
pescottiana seed capsules was smaller than the embryos
of both C. valida and
C. trapeziformis. Despite confirmation of hybridisation,
little evidence for backcrossing was found. Thus, while the specific
pollinator relationships may occasionally break down in these sexually
deceptive orchids, reduced viability of hybrid pollen and
F2 seed, and inefficient pollination of the hybrid, may
minimise introgression. It is concluded from the available evidence that
hybridisation has not been a major evolutionary factor in the diversification
of sexual deception worldwide.
Occurrence of Armillaria luteobubalina and Pathogen-mediated Changes in Coastal Dune Vegetation of South-western Australia
Authors: Shearer B. L. , Crane C. E. , Fairman R. G. , Grant M. J.
Published: August 2004

Sixty-two Armillaria luteobubalina Watling & Kiledisease centres were assessed along the coast from near Cervantes, 160 kmnorth-west of Perth, to Cape Arid, 120 km east of Esperance. Disease centresranged from 0.02 to 6.5 ha in size (mean ± s.e., 1.7 ± 0.2 ha).Most disease centres were active, with mainly old deaths occurring in only7% of centres. Impact was low in only 3% of centres. Diseasecentres mainly occurred on calcareous sands of Holocene dune systems.Susceptible hosts from the Proteaceae, Mimosaceae and Myrtaceae tended to bedominant small trees or shrubs and their death resulted in centres composedmainly of sedges or small shrubs and ground-cover species from a range offamilies. Percentage cover of susceptible plant species was significantly lessin disease centres than adjacent healthy areas. Cover of resistant speciestended to be greater in disease centres than adjacent healthy areas, althoughdifferences were not significant. In association with changes in communitystructure, infection resulted in more bare ground in disease centres thanamongst healthy vegetation. Infection had minimal effect on species richness.The mortality progress curve for the susceptible speciesDryandra sessilis (Knight) Domin increased at a meanapparent infection rate of 0.31 ± s.e. 0.12year-1. A disease centre extended at the rate of 0.004ha year-1 between 1964 and 1983 and 0.07 hayear-1 during the period 1981–1989. Diseaseextension per year was not correlated with yearly rainfall. Threatened taxakilled by A. luteobubalina included the rare andendangered Banksia brownii Baxter ex R.Br.,B. occidentalis R.Br. subsp.formosa Hopper, andB. verticillata R.Br. This is the first report ofdisease significantly altering the structure and composition of coastalvegetation of south-western Australia.Armillaria luteobubalina is a significant additional,and hitherto unrecognised, selection pressure on coastal dune vegetationcommunities, and an important consideration in their management andconservation.
Observations on the Demography of the Australian Boab Adansonia gibbosa) in the North-west of the Northern Territory, Australia
Authors: Bowman D. M. J. S.
Published: August 2004

A study of the size-class distributions of the Australian boab,
Adansonia gibbosa (A.Cunn.) Guymer ex D.Baum, a tree
endemic to north-western Australia, was conducted in Gregory National Park and
Keep River National Park, in the Northern Territory. It was found that
populations of A. gibbosa on alluvial plains had high
densities of small, immature stems < 10 cm dbh (diameter at breast height),
and that the density of immature stems decreased with increasing distance from
a river. By contrast, there was an absence of small size classes in a
population growing on a sandstone escarpment. On limestone substrates, high
densities of small size-class stems were observed at a site topographically
protected from wildfire, but there was an absence of small size classes at a
site exposed to wildfires. Differences in gross allocation patterns, as
inferred from relationships between tree height, trunk diameter and height of
the swollen trunk, were observed between alluvial, sandstone and limestone
substrates. These differences suggest growth rates also differ on distinct
substrates. There was a highly significant negative association between the
presence of fruit and evidence of recent fire damage for stems greater than 10
cm dbh. This pattern may be related to the destruction of reproductive
structures by late dry season fire. However, additional factors appear to
control fruit production, as 36% of the unburnt stems > 10 cm dbh
also lacked fruit. Juvenile plants resprout from swollen tap roots after
wildfire, thus frequent fires would be required to have a long-term impact on
stands of A. gibbosa heavily stocked with juveniles that
possess swollen tap roots. However, it is unknown at what age juveniles
develop swollen tap roots and if all juveniles with swollen tap roots resprout
following fire damage. It is hypothesised that the local distribution of
A. gibbosa is controlled by fire history, and that
changes in fire regimes associated with cattle grazing are causing changes in
the distribution of this species. More research is required to critically
evaluate this conjecture.
Interspecific and Intergeneric Pistil - Pollen Compatibility of Banksia coccinea (Proteaceae)
Authors: Maguire T. L. , Sedgley M.
Published: August 2004

Interspecific and intergeneric pollen-tube growth was investigated using
controlled hand pollinations of Banksia coccinea R.Br.,
35 species of Banksia L.f., and three species of the
related genus Dryandra R.Br. Currently, the relationship
between B. coccinea and other species groups within
Banksia is unclear. Some species supported no
germination of B. coccinea pollen, some supported normal
pollen-tube growth and others produced pollen-tube abnormalities including
thickened walls, bulbous swellings, directionless growth, burst tips and
branched tubes. Control of pollen-tube growth in the pistil was imposed in the
pollen presenter and upper style. There was no significant reciprocal effect
on pollination success in the lower style. The results of pollen-tube
compatability in the lower style indicated that
B. coccinea has a closer affinity to the section
Oncostylis, than the section
Banksia where it is currently placed. Intergeneric
crosses of B. coccinea with
Dryandra species resulted in some compatibility, with
one cross having low numbers of pollen-tubes in the pollen presenter and upper
style region. These results indicate a close relationship between
Banksia and Dryandra, which are
sister genera in the tribe Banksiae, family Proteaceae.
Factors Influencing the Establishment of Seedlings of the Mallee, Eucalyptus luehmanniana (Myrtaceae)
Authors: Tozer M. G. , Bradstock R. A.
Published: August 2004

Factors influencing the survival of seedlings of the wet mallee-eucalypt
Eucalyptus luehmanniana F.Muell. were examined using
seedlings germinated in the laboratory and planted into the field. The effects
of time since fire (0, 13 and 26 years), predation and position relative to
adult canopy on seedling survival and growth in the first year after
establishment were tested experimentally. Drought, predation by invertebrates
and burial in leaf litter were identified as factors causing seedling
mortality. Seedlings were most susceptible to predation at unburnt sites.
Seedlings planted at burnt sites were more susceptible to drought, although a
small percentage were killed by invertebrate predators. Burial of seedlings in
leaf litter was most common under eucalypt canopies. After 200 days, seedlings
in burnt sites were significantly more advanced in height, leaf area and leaf
number than those in unburnt sites. It is predicted that
E. luehmanniana seedlings are unlikely to achieve fire
tolerance before fire occurs (assuming a fire interval of 10–20 years)
unless they establish immediately after fire. The results suggest that mass
establishment cued by fire allows seedlings to avoid predation, however
mortality due to drought was greater at burnt sites than mortality due to
predation at unburnt sites.
Seedling Survivorship of the Beach Morning Glory, Ipomoea pes-caprae (Convolvulaceae)
Authors: Bach Catherine E.
Published: August 2004

Factors influencing seedling survivorship in the beach morning glory,
Ipomoea pes-caprae (L.) Roth, were studied near
Townsville, Queensland, Australia. Censuses of recently germinated seedlings
revealed an 83% mortality rate over a period of 11 weeks. Seedlings
that died occurred significantly further above high-tide line than did
seedlings that were still alive at the end of the study. Although distance to
the nearest neighbouring plants did not influence the probability of survival,
more seedlings survived if their nearest neighbours were monocots than if they
were conspecifics. The probability of survival was greater for seedlings which
were closer to neighbouring seedlings of I. pes-caprae,
but distance to the nearest adult I. pes-caprae did not
affect survival. There was 100% mortality of seedlings that were
naturally buried by sand. A field experiment manipulated levels of insect
herbivory and sand burial, and showed that herbivory caused a seven-fold
increase in mortality rate. Although sand burial also increased mortality,
this effect was not significant. Overall, seedling mortality appeared to be
influenced by both abiotic factors (location on beach, sand burial) and biotic
factors (seedling density, neighbour type and herbivory).
Isolation of Genotype- and Chromosome-specific DNA Markers in a Biotype of Colletotrichum gloeosporioides Using Random Amplified Polymorphic DNA Analysis
Authors: Poplawski Agnieszka M. , Irwin John A. G. , Manners John M.
Published: August 2004

Genetic markers that distinguish fungal genotypes are important tools for
genetic analysis of heterokaryosis and parasexual recombination in fungi.
Random amplified polymorphic DNA (RAPD) markers that distinguish two races of
biotype B of Colletotrichum gloeosporioides infecting
the legume Stylosanthes guianensis were sought.
Eighty-five arbitrary oligonucleotide primers were used to generate 895 RAPD
bands but only two bands were found to be specifically amplified from DNA of
the race 3 isolate. These two RAPD bands were used as DNA probes and
hybridised only to DNA of the race 3 isolate. Both RAPD bands hybridised to a
dispensable 1.2 Mb chromosome of the race 3 isolate. No other
genotype-specific chromosomes or DNA sequences were identified in either the
race 2 or race 3 isolates. The RAPD markers hybridised to a 2 Mb chromosome in
all races of the genetically distinct biotype A pathogen which infects other
species of Stylosanthes as well as
S. guianensis. The experiments indicate that RAPD
analysis is a potentially useful tool for obtaining genotype- and
chromosome-specific DNA probes in closely related isolates of one biotype of
this fungal pathogen.
Plant Regeneration from Cultured Medicago truncatula with Particular Reference to Abscisic Acid and Light Treatments
Authors: Nolan K. E. , Rose R. J.
Published: August 2004

Medicago truncatula (Jemalong 2HA) can be regenerated by
somatic embryogenesis utilising 1-naphthalene acetic acid (NAA) and
6-benzylaminopurine (BAP). There is a requirement for both NAA and BAP for
callus induction and embryo formation. There is no requirement for a drop in
auxin concentration to induce embryos. Abscisic acid (ABA) when present with
NAA and BAP during embryo formation at a concentration of 1 µM,
increases the number of embryos per callus. The ABA treatment stimulates
embryo numbers in both light and darkness. The conversion efficiency of embryo
to plant is unchanged irrespective of the presence of ABA during embryo
formation, indicating that ABA does not improve the regeneration of the
embryos once formed. Importantly, the presence of light in the embryo
formation period causes a marked inhibition of embryo conversion.
Water Relations and Leaf Structure of the Evergreen Shrubs Eurya emarginata (Theaceae) and E. japonica in Coastal and Inland Habitats
Authors: Mishio Masako , Kachi Naoki
Published: August 2004

Stomatal conductance and leaf water potential at around noon, pre-dawn leaf
water potential, pressure–volume parameters, and leaf structural
characteristics including leaf thickness, leaf dry mass per unit area and
turgid leaf water content per unit area were compared between a coastal shrub
species, Eurya emarginata (Thunb.) Makino and an inland
shrub species, E. japonica Thunb. The pre-dawn leaf
water potential was only slightly lower in E. emarginata
than in E. japonica, and the environmental conditions
such as the photosynthetic photon flux density and the vapour pressure deficit
did not differ obviously between the two habitats. No apparent differences
were observed in the pressure–volume parameters between the two species.
On the other hand, E. emarginata had much higher
stomatal conductance and significantly thicker leaves with higher turgid leaf
water content per unit area than E. japonica. The
thicker leaf with higher water content on an area basis in
E. emarginata maintains adequate leaf turgor pressure
against a higher rate of transpiration.
A Post-fire Ecological Study of Xanthorrhoea australis Following Prescribed Burning in the Warby Range State Park, North-eastern Victoria, Australia
Authors: Curtis N. Peter
Published: August 2004

Xanthorrhoea australis R.Br. is considered a
fire-tolerant species, a statement evidently based on established adaptive
traits rather than fire recorded studies. This two-year post-fire study of
X. australis in areas that have been subjected to
prescribed burning in 1976 and 1991 compares results with a site unburnt for
about 100 years. In the sites burnt in 1991, arborescent plants had a
mortality of between 10% and 40% (average 21%), with
highest mortality in the youngest and oldest plants, and in the site with the
lowest plant density. In the site burnt in 1976, plants were still dying.
Mortality of plants in the unburnt site was 4%. Flowering in the first
post-fire spring varied from 0–100% throughout the size classes,
with no flowering observed in plants smaller than 0.5 m. In the unburnt sites
and the 1976 burnt sites, where understorey protected seedlings, recruitment
was significantly higher (P < 0.001) than in the
areas burnt in 1991 that had little ground cover. Plants with severe burn
damage to stems at ground level often developed leans (P
< 0.001) that were more often opposite to the burnt side
(P < 0.001). Leans increased from 2.5˚ to
35˚, and some plants continued to grow, lying horizontally. In all fire
sites the horizontal plants had a mortality of 44–92% compared
with 29% for those in the unburnt site. In some sites, particularly in
areas of high soil moisture, 3–10% of plants developed epicormic
shoots after their stems fractured, or their shoot apices died. The study
showed that fire has a long-term deleterious effect on large plants of this
species. These data should be taken into account by authorities engaged in
prescribed burning in forests with significant stands of this species.
The Influence of Fruit and Bud Volumes on Eucalypt Flowering—An Exploratory Analysis
Authors: Keatley Marie R. , Hudson Irene L.
Published: August 2004

The appearance of buds and development of fruits in 51 species of
Eucalyptus L’Hér. were examined to
determine whether bud and fruit volume had an influence on flowering. These
variables exert an influence on eucalypt flowering as individuals and as
members within an umbel. Flowering earlier in the growing season is
characteristic of species with large, individual bud and fruit volume and
those that have a large umbel volume. The number of buds and fruits in an
umbel is influenced by volume of the individuals. Development time of buds was
longer in umbels which had a larger total volume. Bud and fruit umbel volume
was positively correlated with the timing of bud appearance as was seed
maturity with individual fruit and fruit umbel volume. A threshold of bud and
fruit volume was indicated below which seed maturity and time of flowering is
not reflected by volume. Discriminant analysis used nine predictors to assign
80% (overall) of section members of Adnataria
(91%), Bisectaria (60%),
Maidenaria (67%) and
Renantheria (87%) to their true groups. Across
groups examination adduced the possibility of each group having a distinct bud
development period and a discernible cessation of flowering. Five clusters
were revealed whose members were significantly differentiated on seed
maturity, section, individual fruit volumes, bud and fruit umbel volumes.
Factor analysis outlined four factors—buds, fruits, timing and
development—which accounted for 78.9% of the variance.
Interactions between Plant Competition and Herbivory on the Growth of Hypericum Species: a Comparison of Glasshouse and Field Results
Authors: Willis Anthony J. , Groves Richard H. , Ash Julian E.
Published: August 2004

The combined effects of interspecific plant competition and herbivory by a
mite, Aculus hyperici Liro, on the growth of two
Hypericum species were compared in separate glasshouse
and field experiments. The impact of mites on
H. perforatum L. was slightly greater than their effect
on H. gramineum Forst. In both the glasshouse and the
field, competition affected Hypericum growth more
adversely than herbivory. There was little evidence that combinations of
competition and herbivory caused complex synergistic reductions in plant
productivity. In combination, herbivory and competition caused proportional
reductions in growth, approximately equivalent to the product of the
proportional growth under competition and herbivory individually. Broadly
similar results were achieved in both the glasshouse and the field experiment.
The results are discussed in relation to the biological control of
H. perforatum by A. hyperici, and
the impact of this arthropod on the growth of
H. gramineum, a non-target native species.
Plant Ecophysiology: Linking Pattern and Process—a Review
Authors: Williams Jann , Eamus Derek
Published: August 2004

Introduction
The Symposium ‘Plant Ecophysiology: Linking Pattern and Process’
was held as part of the 1995 meeting of the Ecological Society of Australia
(ESA). The aim of the Symposium was to highlight work that examined mechanisms
underlying ecological patterns and linked them to ecological and/or
evolutionary processes. Another aim was to expose ecologists to the methods
available to examine the mechanistic and functional basis of the organisms and
systems under study. Much early ecological research has been concerned with
the description and classification of vegetation types, with relatively little
effort devoted to understanding the underlying processes that determined
distribution.
A more quantitative approach based on knowledge of the underlying mechanisms
can further improve understanding of systems. This was amply demonstrated in a
Symposium on the effects of elevated atmospheric CO2 on
vegetation dynamics, also held in conjunction with an ESA meeting (see papers
in Australian Journal of Botany, Volume 40(2)). Recent
technological advances have stimulated rapid progress in the field of
ecophysiology and hence an increasing process-based understanding is
developing.
The 1995 Symposium was seen as an opportunity to highlight more recent work in
what is a relatively new field in Australia (albeit a well-established field
in Europe and America), especially in situ studies and
research from relatively little studied areas like northern Australia. The
response to the Symposium was encouraging, with 25 spoken papers and
poster-papers presented. In this paper, some of the unifying aspects of the
papers presented in the symposium are drawn together, and placed in the
context of likely future developments in ecophysiology in Australia. Based on
this analysis, future directions and gaps are identified.
Unique Stigmatic Structure in Three Genera of Proteaceae
Authors: Ladd P. G. , Nanni I. , Thomson G. J.
Published: August 2004

In three closely related genera of the Proteaceae, namely,
Lomatia R.Br., Stenocarpus R.Br.
and Strangea Meisn. the pollen presenter and stigma at
anthesis are covered by specialised cells. The cells are spiral-walled,
contain polyphenolic material and are produced from the stigma, and in
Lomatia from the pollen presenter. The spiral
wall-thickenings are formed on the inside of the primary wall late in the
development of the cells when they are budded off from the stigma or presenter
surface. Pollen from the anthers is placed onto these cells from where it is
taken to other flowers for cross-pollination. The spiral-walled cells prevent
contact between self-pollen and the stigma and provide a method whereby
cross-pollen can only reach the stigma if self-pollen has been removed. The
form of the cells and the mechanism for preventing autogamy is not found in
any other plant group.
Co-existence, Demography and Distribution Patterns of Two Co-occurring Ecologically Equivalent Fynbos Proteaceae Species
Authors: Midgley J. J. , Enright N. J. , Cowling R. M.
Published: August 2004

Leucospermum conocarpodendron (L.) Beuk. and
Mimetes fimbriifolius Salisb. ex J.Knight co-occur in
the southern Cape Peninsula, where we studied their distribution patterns,
demography and fire responses.
Leucospermum conocarpodendron has relatively larger
seedlings and is therefore the likely competitive dominant. Adults and
seedlings of both species are widely spaced and interspecific competition is
unlikely to cause competitive exclusion. Differences between the two species
in recruitment levels and fire-mortality are small. Thus their size-class
distributions are very similar. They are restricted to shallow-soil rocky
habitats, not only because of reduced fire intensity in these sites, but
because these are habitats avoided by the faster growing more competitive
reseeding Proteaceae. Co-existence of these two species appears to mainly be
due to fire keeping populations sparse, and ants keeping individuals fairly
isolated.
Two Hundred Years of Land Use and Vegetation Change in a Remnant Coastal Woodland in Southern Australia
Authors: Lunt Ian D.
Published: August 2004

Post-settlement changes in vegetation and land use were examined in a
reputedly undisturbed woodland remnant at Ocean Grove, southern Victoria, the
site of earlier ecological studies. The vegetation has passed through at least
three structural phases since European colonisation: an open grassy woodland
dominated by Allocasuarina and
Eucalyptus species and
Banksia marginata Cav. with few shrubs; an open scrub of
Acacia pycnantha Benth.; and a closed scrub of
Allocasuarina littoralis (Salisb.) L.A.S.Johnson, which
now dominates the reserve. Tree and shrub density has progressively increased,
from perhaps less than 20 trees ha–1 in the early
1800s, to over 3000 trees ha–1 in 1996. Most large
Allocasuarina trees established in the late 1930s or
early 1940s, and Allocasuarina littoralis appears to
have invaded rapidly thereafter. Surprisingly,
A. littoralis was not recorded in an 1894 plant census,
and might have been locally rare last century. Vegetation changes over the
past 200 years can be attributed to the long-term absence of fire. The
abundant recruitment of Acacia species in the mid- to
late-1800s may have been a rapid response to the curtailment of Aboriginal
burning, and the more recent invasion of A. littoralis a
longer-term response to fire exclusion. The importance of active vegetation
management for biodiversity conservation in the future is stressed.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXXIV Synthesis and Structure of the 1 : 1 Adduct of Silver(I) Nitrate with Triphenylstibine
Authors: Effendy  , Kildea John D. , White Allan H.
Published: August 2004

The synthesis and room-temperature single-crystal X-ray structure
determination of the 1 : 1 adduct of silver(I) nitrate with triphenylstibine,
AgNO3/SbPh3 (1 : 1), is
recorded, being monoclinic,
Cc,a
12·824(2), b
15·794(4),c 9·796(2) Å, β
117·50(1)°, Z= 4; conventional
R on F was 0·030 for 2881
independent ‘observed’ (I > 3σ(I)) reflections. The
complex is a one-dimensional polymer with bridging nitrate groups, resembling
in this respect its phosphine and arsine analogues. The completion of this
study, along with related species recorded in accompanying papers, means that
full structural data are now available for the complete array
AgNO3/EPh3 (1 :
n), E = P, As, Sb, n
= 1–4, with the one exception of E = Sb,
n = 2.
Structural Characterization of Some Novel Oxidation Products of Triphenylstibine
Authors: Effendy  , Grigsby Warren J. , Hart Robert D. , Raston Colin L. , Skelton Brian W. , White Allan H.
Published: August 2004

Room-temperature single-crystal X-ray structural characterizations of two
oxidation products of triphenylstibine of the form
XPh3SbOSbPh3X are recorded for X
= Cl, NO3.
ClPh3SbOSbPh3Cl is monoclinic,
P 21/c,
Z = 4 f.u., a
9·109(4), b 19·809(8),
c 19·30(2) Å, β 109·27(5)°,
conventional R on F being
0·038 for No 4431
‘observe’ (I > 3σ(I)) independent reflections. In this
complex, Sb-O-Sb is quasi-linear, 173·1(3)°, in contrast to the
previously recorded benzene solvate, in which it is 139·0(3)°; in
the nitrate,
[(O2NO)Ph3SbOSbPh3(ONO2)],
triclinic, P-1,
Z = 2 f.u., a
15·609(5), b 13·238(4),
c 10·140(2) Å, α 87·11(2),
β 88·46(7), γ 72·93(2)°, R
0·036 for No 5275, it is
also bent (137·0(2)°). The anionic substituent is opposed to the
oxo bridge in the trigonal bipyramidal five-coordinate array about the metal
in both complexes. A redetermination of the structure of
Ph8Sb4O6 is
recorded, presenting a non-disordered model in a triclinic
P-1 cell, a
19·98(3), b 11·635(2),
c 9·739(2) Å, α 92·28(1),
β 98·98(1), γ 99·74(1)°, Z
= 2 f.u., R 0·046 for
No 3578. A new
(‘β’) phase of triphenylstibine, crystallized from
hexane/toluene is also recorded: monoclinic, P
21/c, a
15·386(8), b 11·304(5),
c 19·078(8) Å, β11·64(4)°,
Z = 8, R 0·045 for
No 3393.
Reaction of Aquatic Humic Substances with Manganese and Chromium
Authors: Lu Xiao-Qiao , Johnson W. David , Howe Russell F. , Chen Yun-Yun
Published: August 2004

Ultraviolet-visible and e.s.r. spectroscopies have been used to investigate
the reactions of humic substances, extracted from swamp waters, with
manganese(VII) and with chromium(VI). Potassium permanganate reacts quickly
with humic substances to form manganese(II) derivatives. Phenolic groups are
probably involved as a similar reaction occurs with simple phenols such as
phenol and catechol. Manganese(II) interacts directly with carboxylate anionic
groups in humic substances. E.s.r. spectroscopy shows that manganese(II) forms
outer-sphere complexes with humic substances. E.s.r. spectra show that
chromium(VI) is reduced to chromium(V) and then to chromium(III) in the
presence of humic substances. The rate reduction of chromium(VI) depends on
the concentration of humic substances and on pH, temperature, and u.v.-visible
radiation. At pH 3 the rate of formation of chromium(V) is about 100 times
faster than the rate of its reduction. At neutral pH and at room temperature
the chromium(V) species is stable for a long period.
A/C-Ring Colchicine Analogues: a Comparison of Molecular Conformations of the Minimized and Crystal Structures
Authors: Ang Kiah H. , Greenwood Richard J. , Mackay Maureen F. , Wong Margaret G.
Published: August 2004

Molecular mechanics and molecular orbital calculations have been used to
determine the low-energy conformations of six biaryl analogues of colchicine
lacking the seven-membered B-ring. A comparison of the conformations resulting
from the different minimizations has been made, and these conformations were
also compared with those found in the solid state for the respective biaryl
analogues and the A/C-ring systems of colchicine and isocolchicine. The
barriers to rotation about the A/C-linkage of the analogues were estimated
from rotational plots. The MM+ calculations were not satisfactory for
estimating the barriers, whilst the MMX, MAXIMIN2 and AM1 values, although
agreeing on average only to within 16 kJ mol-1 ,
exhibited the expected trend in magnitude. This trend, however, did not
correlate with the inhibition of tubulin polymerization to microtubules.
The Chemistry of Lauren-1-ene. XVII Preparation of Unsaturated Oxa and Aza Tetracycles.
Authors: Chin Anna Fu Oi , Hanton Lyall R. , Weavers Rex T.
Published: August 2004

Several lauren-1-ene-derived compounds containing an exocyclic methylene
grouping have been synthesized. These include substances with both regular and
rearranged carbon frameworks. The X-ray structure of a rearranged α-methylene
lactone shows that an earlier assignment of stereochemistry is incorrect and
that this compound has an exceptionally distorted C=C-C=O unit.
The methylene derivatives prepared have proved to have low cytoxicity.
Copper Selenocyanate Formation on the Copper Anode.
Authors: Kilmartin Paul A. , Wright Graham A.
Published: August 2004

The formation of CuSeCN on a copper anode was studied in 0·1 and
0·5 mol dm-3 KSeCN solutions. A thin film of
polycrystalline CuSeCN was produced with a midpoint potential between the
anodic and cathodic peaks for 0·1 mol dm-3 KSeCN
at - 0·253 V, close to the open-circuit potential of - 0·249 V.
A precursory anodic peak or shoulder was seen at about - 0·210 V, and
was ascribed to the formation of a primary (barrier) film. The anodic peak
currents for the primary film were linearly dependent upon the sweep rate.
Potential steps into the primary film region produced current transients, with
the current decaying in proportion to the reciprocal of time. The anodic peak
current and potential for the secondary polycrystalline film were proportional
to the square root of the sweep rate, an effect which is consistent with a
model for porous film growth controlled by the resistance across the
underlying barrier film. A weak Raman band due to Se-bonded CuSeCN at 2164
cm-1 was also observed in situ.
Syntheses of 6-Substituted Truncated Yuehchukene Analogues.
Authors: Cheng Kin-Fai , Cheung Man-Ki , Kong Yun Cheung
Published: August 2004

Facile syntheses of
2-t-butyl-3-(indol-3′-yl)-1,2,3,4-tetrahydrocyclopent[b]indol-6-ol
(3), and its 6-methoxy (4) and 6-acetyloxy (5) derivatives are described.
Avarol and Related Compounds from the New Zealand Marine Sponge Dysidea sp.
Authors: Stewart Michael , Fell Patrick M. , Blunt John W. , Munro Murray H. G.
Published: August 2004

Bioassay and t.l.c. guided separation of extracts from the New Zealand marine
sponge Dysidea sp. has led to the isolation of avarol
(1), six other known compounds (2)–(4) and (6)–(8), and seven new
compounds (9)–(15). All but one of these, compound (8), are related to
avarol. The structures of all the compounds have been established by
spectroscopic methods.
Preparation and X-Ray Structure of cis-3-Pentamethyldisilanylcyclohexyl p-Nitrobenzoate
Authors: Green Alison J. , White Jonathan M.
Published: August 2004

The title compound was prepared in three steps from cyclohex-2-enone. The
C(alkyl){O(ester) bond distance is 1·471(3) Å which is not
significantly different to that for other cyclohexyl
p-nitrobenzoates. This suggests that the
γ-pentamethyldisilanyl substituent has very little effect on the ester
substituent in the ground state.
A Saturated Heterocycle Formed from Ethane-1,2-diamine, Formaldehyde and Nitroethane: Crystal Structure of 6-Methyl-6-nitro-1,4-bis(2′-nitropropan-1′-yl)-1,4-diazacycloheptane
Authors: Rossignoli Monica , Hambley Trevor W. , Lawrance Geoffrey A. , Maeder Marcel
Published: August 2004

The substituted saturated seven-membered heterocycle
6-methyl-6-nitro-1,4-bis(2′-nitropropan-1′-yl)-
1,4-diazacycloheptane crystallizes readily as a product from the reaction
between
[Re(en)2O2]+
(en = ethane-1,2-diamine), formaldehyde and nitroethane in basic
solution. The complex apparently acts as a ‘molecular tap’,
releasing en very slowly for reaction and favouring formation of discrete
molecules rather than polymers, which form when free en alone is employed in
the presence or absence of perrhenate ion. The trinitro cycloalkane
crystallizes in the space group Pbca, with
a 11·131(2), b
14·919(3), c 20·662(4) Å.
A-CH2-C(CH3)(NO2)-CH2-
chain links the two original primary amines of the ethane-1,2-diamine, in the
same way that this type of chain links two primary amines of different
ethane-1,2-diamine molecules in related metal-directed reactions. Further
condensation involving the two secondary amines in the heterocycle
intermediate leads to two
-CH2-CH(NO2)-CH3
pendants being formed, the relatively insoluble final product crystallizing
readily from aqueous solution.
β-Acarbose. II. The Preparation of Various Carbohydrate Trifluoromethanesulfonates
Authors: McAuliffe Joseph C. , Stick Robert V.
Published: August 2004

Three carbohydrate trifluoromethanesulfonates, of potential use in the
alkylation of a 1-epivalienamine derivative to produce precursors of
β-acarbose, have been prepared from the appropriate alcohols. The
conversion of two of these trifluoromethanesulfonates into the primary amine,
via the corresponding azide, is also reported.
Fused Tetracyclic Quinoxalines from Reactions of o-Phenylenediamines in Polyphosphoric Acid
Authors: Deady Leslie W. , Kaye Anthony J.
Published: August 2004

The condensation of 2,3-diaminobenzoic acid and the 5-chloro derivative with
o-hydroxyphenylglyoxylic acid, isatin and
benzothiophen-2,3-dione in polyphosphoric acid leads to the appropriate
tetracycles. Isomeric products are formed from these unsymmetrical diamines,
and methods of assigning particular structures are described.
Crystal Structure of mer-(PMe3)-trans(PEt3)(PPri3)H-trans-Cl2Ir III at 146 K
Authors: Ditzel Evert J. , Griths K. David , Robertson Glen B.
Published: August 2004

The structure of the novel mixed-phosphine complex
mer(PMe3)-trans(PEt3)(PPri3)H-trans-Cl2IrIII
has been determined by single-crystal X-ray diffraction analysis at
146±3 K. Crystals are monoclinic, space group P
21/c, with
a 7·414(4), b
15·073(3), c 9·796(2) Å, β
97·46(1) and Z 4. Structure refinement by
constrained (2xC-C distances) full-matrix least-squares analysis (2378 unique
reflections, 217 parameters) converged with R
0·049 and ωR 0·055. The
PPri3 ligand is face-to-face
configured with the unique Pri group eclipsing the
hydride ligand. The PEt3 ligand is asymmetrically
configured with Ir-P-C-C torsion angles 174, –72 and –146°.
Metal{ligand distances are: Ir{P(1,2,3) 2·366(4),
2·372(4), 2·306(4) Å; Ir-Cl(1,2) 2·386(4),
2·372(4) Å. The P-Ir-P(trans) angle is
157·2(1)°.
Synthesis and Characterization of Stilbene Derivatives for Possible Incorporation as Smart Additives in Polymers Used as Packaging Films.
Authors: Day Gary M. , Howell Owen T. , Metzler Michael R. , Woodgate Paul D.
Published: August 2004

Several series of stilbene derivatives for possible use as smart additives in
polymers used as packaging films have been prepared and characterized.
Differential scanning calorimetry was performed on some of the stilbenes in
order to determine any liquid crystal properties. Those compounds which had
multiple phase transitions were also shown to have two liquid crystalline
phases according to optical microscopy.
Theoretical Studies on the Effect of the Medium on Tautomeric Phenomena in Neutral and Protonated Acridin-9-amine. Mechanism of Tautomerization in Neutral Entities
Authors: Rak Janusz , Skurski Piotr , Jozwiak Ludwika , Blazejowski Jerzy
Published: August 2004

Semiempirical AM1 and PM3 (gaseous phase) and AM1-COSMO, PM3-COSMO and PM3-AQ
(liquid phase) methods were used to examine the structure, as well as the
thermodynamic and physicochemical features (dipole moments and LUMO and HOMO
energies), of tautomeric forms of neutral, mono- and di-protonated
acridin-9-amine. The energy gaps between possible tautomers are only
insignificantly influenced by the medium and reveal the coexistence of neutral
and diprotonated entities in two forms, and the monoprotonated entity in one
form. Entropy and thermal energy, which can be evaluated only for gaseous
systems on the basis of statistical mechanics, both increase with temperature
and affect equilibria between tautomers. The mechanism of bimolecular
tautomerization of neutral acridin-9-amine was examinated by the PM3 and
PM3-AQ methods. The inclusion of entropy changes accompanying tautomerization
in the gaseous phase enabled high-pressure-limit rate constants for
well-defined steps of the process at the RRKM and transition state level of
theory to be predicted. Thermodynamic and kinetic considerations indicate that
neutral acridin-9-amine should coexist in amino and imino tautomeric forms,
and that both these entities can convert into each other at moderate
temperatures.
Electronic and Structural Properties of Iron(II) and Nickel(II) Cationic Complexes of 2-(Pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole
Authors: Childs Bradley J. , Cadogan John M. , Craig Donald C. , Scudder Marcia L. , Goodwin Harold A.
Published: August 2004

Complex salts containing the
[FeIIN6]2+
derivative of 2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole (pzaptH) undergo
continuous, temperature-induced singlet
(1A1) quintet
(5T2) transitions with the
transition temperature being dependent on the nature of the counter anion and
the presence of solvate water, the latter tending to stabilize the singlet
state. A transition is also observed for the fluoroborate salt in methanol
solution. The extent of stabilization of the singlet state for iron(II) in
these complexes is somewhat greater than in those derived from the previously
studied 2-(pyridin-2-ylamino)-4-(pyridin-2-yl)thiazole. The crystal structures
of [Fe(pzaptH)2]
[CF3SO3]2
and [Ni(pzaptH)2]
[BF4]2.2H2O
have been determined. The average Fe-N distance is 1·985 Å, a
value consistent with the essentially low-spin nature of the complex at room
temperature, and the average Ni-N distance is 2·089 Å. In both
complexes the bridging >NH group is involved in hydrogen bonding to the
anions and, in the nickel complex, also to the solvate water. The
uncoordinated nitrogen of the pyrazine ring is not hydrogen-bonded.
Bis[2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole]iron(II)
triflate: triclinic, space group P
-1, a 8·794(5),
b 11·082(6), c
17·49(1) Å, α 77·59(4), β 86·80(4), γ
84·21(4)°, Z 2.
Bis[2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole]nickel(II)
tetrafluoroborate dihydrate: monoclinic, space group P
21/c, a 8·784(3),
b 8·795(2), c
41·16(1) Å, β 94·58(2)°, Z
4.
An Ab Initio Molecular Orbital Study of Sulfur-Substituted Carbanions: Toward an Understanding of Regiochemistry in the Chlorination of Unsymmetrical Sulfides
Authors: Ginsburg Jack Leon , Darvesh Katherine Valenta , Axworthy Patricia , Langler Richard Francis
Published: August 2004

Moller-Plesset molecular orbital calculations at the 6-31+G(d) level have
been completed on substituted dimethyl sulfide-derived carbanions. The results
are applied to the prediction of regiochemistry for chlorination of
unsymmetrical sulfides. Notwithstanding the need for future improvements,
regiochemical predictions based on stabilities of sulfur-substituted
carbanions match experimental results better than earlier predictions based on
stabilities of sulfur-substituted carbonium ions or sulfur-substituted free
radicals. The present results suggest that the mechanism for the elimination
step in the Pummerer rearrangement of a chlorosulfonium cation is an
E 1cb-like process.
Chemistry of meso-Dimethylaminopropenyl- porphyrins and -bisporphyrins: the Synthesis of Australochlorin, a Benzochlorin Isomer.
Authors: Yashunsky Dmitry V. , Ponomarev Gelii V. , Moskovkin A. S. , Arnold Dennis P.
Published: August 2004

The nickel(II) complex of
meso-dimethylaminoprop-1-enyloctaethylporphyrin (2c) was
converted by quaternization and thermolysis into a pair of novel isomeric
macrocyclic complexes (3) and (4). These have a fused six-membered ring, and
an exocyclic double bond on the neighbouring β-position, and have been
named ‘australochlorins’. Heating these compounds in acetic acid
leads to the known nickel(II) octaethylbenzochlorin (1) and a novel
β-(1-acetoxyethyl)benzochlorin (5). Trifluoroacetic acid promotes the
regioselective formation of benzochlorin/porphyrin species from the
mononickel(II) complexes of the acrolein derivatives of
bis(octaethylporphyrinyl)ethane and trans-ethene.
The Preparation and Crystal Structure of a Unique Bismuth Complex with Ethylene Glycol: the Tris[ethane-1,2-diolato(2 - )]dibismuth(III) Polymer Hydrate
Authors: Cloutt Brett A. , Sagatys Dalius S. , Smith Graham , Bott Raymond C.
Published: August 2004

A novel efflorescent complex of bismuth(III) with ethylene glycol has been
synthesized, and its structure determined by single-crystal X-ray diffraction
and refined to a residual R 0·055 for 1811
observed reflections. Crystals are triclinic, space group
P-1, with two dimers forming the
asymmetric unit in a cell with dimensions a
8·885(3), b 10·796(4),
c 7·586(3) Å, α 93·19(3),
β 106·61(3), γ 105·72(3)°. The
[Bi2(C2H4O2)3]
dimer unit, which comprises two different bismuth centres, one five-, the
other six-coordinate, is extended into a stable three-dimensional polymer
framework via associations through all three ethane-1,2-diolato(2– )
ligands which are bidentate and, in most cases, bridging. The lattice also
contains weakly associated but uncoordinated molecules of hydration which are
considered responsible for the crystal instability.
The Synthesis of Some Seleno- and Telluro-β-D-glucopyranosides
Authors: Stick Robert V. , Tilbrook D. Matthew G. , Williams Spencer J.
Published: August 2004

Several new seleno- and telluro-β-D-glucopyranosides have been prepared by
treatment of protected α-D- glucopyranosyl bromides with the appropriate
dialkyl or diaryl dichalcogenide and sodium borohydride in ethanol.
Structural, Magnetic and Mössbauer Studies of Bis(2,6-bis(pyrazol-3-yl)pyridine)iron(II) Triflate and its Hydrates
Authors: Sugiyarto Kristian H. , Weitzner Karyn , Craig Donald C. , Goodwin Harold A.
Published: August 2004

The electronic properties of bis(2,6-bis(pyrazol-3-yl)pyridine)iron(II)
triflate depend markedly on the extent of hydration. The trihydrate is low
spin while the monohydrate is high spin at room temperature but undergoes a
discontinuous transition to low spin at low temperatures. In the anhydrous
complex magnetic and Mössbauer spectral data indicate that there is a
minor fraction of low-spin species at room temperature and this fraction
increases at low temperatures. The spin transition in the anhydrous salt is
continuous and incomplete at 80 K. The structure of the trihydrate reveals an
extensive hydrogen-bonding network which involves the uncoordinated >NH
groups of the pyrazolyl groups in the ligands, the water molecules and the
anions. The disruption of this network on loss of water is believed to be
responsible for the change in electronic properties.
Bis(2,6-bis(pyrazol-3-yl)pyridine)iron(II) triflate trihydrate: triclinic,
space group P-1,
a 11·490(5), b
12·218(6), c 13·666(6) Å, α
104 ·67(2), β 104·58(2), γ 104·35(2)°,
Z 2.
Oxidation Products of Totara-8,11,13-trien-13-ol Derivatives
Authors: Beckett Kirsten S. , Bendall Justin G. , Cambie Richard C. , Rutledge Peter S. , Walker Michael F. , Woodgate Paul D.
Published: August 2004

Reaction of 7-oxototara-8,11,13-trien-13-yl acetate (3) with acetic
anhydride-perchloric acid affords the γ-pyrone (8) in addition to the
previously reported acetyl derivative (4). Baeyer–Villiger oxidations of
the ketones (3) or (5) have given starting material or complex mixtures, but
the ε-lactone (9) and the rearranged product (11) were isolated from two
experiments with (3). Oxidation of 13-methoxytotara-8,11,13-triene (2) with
Jones reagent gives the 7-oxo derivative (5) and a low yield of a ring B
opened substituted p-benzoquinone (13). Pathways to (11)
and (13) are proposed.
An ab initio Study of the Fulminate Anion-Cyanate Anion Rearrangement: Possible Intermediacy of the Oxazirinyl Anion
Authors: Cheung Yu-San , Li Wai-Kee
Published: August 2004

The rearrangement of the fulminate anion (CNO¯) to the cyanate anion
(OCN¯) has been studied with high-level ab initio
methods. Geometry optimizations have been carried out at HF,
MPn (n = 2-4), QCISD,
QUISD(T), BD and BD(T) levels using the 6-31+G(d) basis set. The highest
level of theory for the calculation of relative energies is
QCISD(T)/6-311+G(3df, 2p). Results show that the rearrangement
proceeds via an oxazirinyl anion intermediate, which is separated by barriers
of 52·8 and 18·4 kJ mol-1 from CNO¯
and OCN¯, respectively.
Electrical Conductivity, Viscosity and Molar Volume of Potassium Nitrate - Sodium Nitrate in Cadmium Nitrate Tetrahydrate Melt
Authors: Kalita Gautam , Rohman Nashiour , Mahiuddin Sekh
Published: August 2004

The electrical conductivities, viscosities and molar volumes of the
0·3[xKNO3+(1
– x)NaNO3]+
0·7Cd(NO3)2.4·4H2O
systems were measured as functions of temperature (293·15 ≤
T/K ≤ 363·15) and composition
(x = 0·0 to 1·0 mole fraction). The
temperature dependence of the electrical conductivity and viscosity was
non-Arrhenius in nature and has been analysed by using the
Vogel–Tammann–Fulcher (VTF) equation. Both conductivity and
viscosity vary non-linearly with the molar volume and have been explained by
using VTF-type equations based on the free volume model. In the present system
the molar volume and the intrinsic volume are additive. A significant mixed
alkali effect has been observed in the normalized electrical conductivity and
viscosity and in the electrical conductivity at the isofluidity condition. The
variation of the electrical conductivity is governed by the mobility of the
potassium ions. The onset of the mixed alkali effect has been explained by the
anion polarization model.
Observations Relating to the Mode of Formation of Cyclopropylidene Dimers in the Reaction of gem-Dibromocyclopropanes with Methyllithium
Authors: Banwell Martin G. , Hockless David C. R. , Longmore Robert W. , Walter Justine M.
Published: August 2004

Treatment of the gem-dibromocyclopropane (5) with methyllithium in diethyl
ether at –80°C gives not only the syn- and
anti-cyclopropylidene dimers (12) and (13),
respectively, but the related species (14) and (15) as well. The isolation of
this latter pair of products lends weight to the argument that
β-halobicyclopropylyllithium compounds such as (18) are the immediate
precursors to the cyclopropylidene dimers.