bluuebunny/crossref_metadata_2025 huggingface dataset:
Field assessment of aeroponically grown and nodulated Acacia mangium
Authors: Martin-Laurent Fabrice , Tham Foong-Yee , Lee Sing-Kong , He Jie , Diem Hoang G.
Published: September 2002

Acacia mangium seedlings were grown and nodulated with
selected elite strains of Bradyrhizobium spp. under
aeroponic conditions. The aeroponics system is well known for furnishing a
very rich air environment around the roots and has been shown in our earlier
work to induce rapid growth and enhance performance of
Acacia seedlings under greenhouse conditions. This paper
reports that the positive effects on growth, such as increased height and leaf
area, induced by aeroponic culture with the
Bradyrhizobium strains, Tel 2 from
Malaysia and Aust 13c from Australia, continued to be
sustained for 4 months after plants were transferred to field conditions.
Random sampling and analyses of Bradyrhizobia by
polymerase chain reaction–restriction fragment length polymorphism
(PCR–RFLP) also showed that Aust 13c continued to
persist in root nodules of inocualated plants in the field, with inoculated
plants having significantly higher nitrogen and phosphorus concentrations as
well as higher photosynthetic rates than non-inoculated controls. The
A. mangium plants were only 8 months old from
germination but had already reached mean heights of approximately 2.4 m. The
results suggest that aeroponic growth and nodulation should be further
investigated for their potential to promote growth of
A. mangium, especially on difficult soils.
Sex-specific differences in floral display and resource allocation in Australian alpine dioecious Aciphylla glacialis (Apiaceae)
Authors: Pickering Catherine Marina
Published: September 2002

In one of the few dioecious species in the Australian alpine region,
Aciphylla glacialis (F.Muell.) Benth. (Apiaceae)
flowering and resource allocation patterns were found to differ between males
and females, potentially a response to sex-specific selection under the
limited conditions for growth and reproduction imposed by the alpine
environment. Sex ratios were male biased with approximately 1.49 males to each
female in each of five populations of A. glacialis. Male
plants had larger floral displays than female plants, producing four times as
many flowers per inflorescence and an average of 3.5 inflorescences per plant,
compared to 2.9 inflorescences for females. Male and female plants commenced
flowering within a few days of each other (average 18 January for males, 19
January for females) but female plants completed flowering earlier, finishing
at the end of January, while males were still flowering well into February.
Male and female plants did not differ in size as estimated by the number of
stems per plant, nor in the proportion of resources allocated to reproduction
compared with above ground vegetative structures. However, they did differ in
the way resources were allocated to vegetative and floral structures,
particularly among larger plants. Large female plants produced heavier stems
and infloresences than males. Heavier inflorescences in females may be
associated with the need for greater structural support for inflorescences
when fruiting, while the increased dry weight of stems may reflect differences
in the ways in which the sexes match growth and resource demands for
flowering.
Factors affecting post-fire seedling establishment of selected mallee understorey species
Authors: Cohn J. S. , Bradstock R. A.
Published: September 2002

Factors affecting the survival of post-fire germinants in mallee communities,
in central western New South Wales, were examined. Experiments compared the
relative effects of native and introduced herbivores (kangaroos, goats,
rabbits), after small- and large-scale fires (20–50 and > 10 000 ha,
respectively), with particular emphasis on edge effects, seedling clustering,
topography and eucalypt canopy presence. The experiments (1985–1997)
focused on common understorey species Acacia rigens
Cunn. ex Don, A. wilhelmiana F.Muell. and
Triodia scariosa N.T.Burb. subsp.
scariosa, in mallee dominated by
Eucalyptus species. Following a large fire (1985), high
spring rainfall and rabbit grazing on A. rigens only,
survival of Acacia species and
T. scariosa remained relatively high 4 years later
(60–70%). After small burns (1987, 1988), low spring rainfall and
grazing by rabbits and kangaroos, survival of Acacia
species declined to between 0 and 30% of the germinants by the second
summer. In most cases, local extinction had occurred within 8 years. After
small burns (1988, 1989) and low spring rainfall, the survival of
T. scariosa declined to between 0 and 35% of
germinants by the second summer (effect of grazing unknown). No consistent
effect of edge, topography and eucalypt canopy was found. Survival of
clustered Acacia seedlings was between 10 and 20%
lower than unclustered seedlings. Given the high frequency of low rainfall and
its interaction with grazing, prescribed burning of mallee for wildfire
control and nature conservation may require the local elimination of rabbits
and a reduction in kangaroo numbers, especially in the first spring and summer
following seedling germination.
Vegetation of the Wessel and English Company Islands, North-eastern Arnhem Land, Northern Territory, Australia
Authors: Woinarski J. C. Z. , Brennan K. , Cowie I. , Fisher A. , Latz P. K. , Russell-Smith J.
Published: September 2002

Vegetation patterning is described for two neighbouring continental island
chains off Arnhem Land, Australia. A total of 684 species was recorded from 57
islands, with reasonably comprehensive lists for 36 of these islands. Almost
90% of the deviance in plant species richness was associated with
island size. The richness of plants dispersed by sea and/or vertebrates
was proportionally greater on small islands; that of relatively poor
dispersers was greater on larger islands. Twelve vegetation communities were
defined by classification of plant species composition in 226 50 × 50-m
quadrats. There was no relationship between island size and species richness
at the quadrat level, at least for the most extensive vegetation types. The
vegetation of the islands is now composed of two main elements—an
original set of communities (mostly of heath, tussock grassland and eucalypt
open forest) whose species have poor inter-island dispersal, and a set of more
recent colonists (mostly of strand, mangrove and coastal thicket communities).
The former group is allied to the sandstone flora of western Arnhem Land, but
is species-poor in comparison, as the islands lack the deep gorges which drive
much of the species richness of western Arnhem Land. The latter group
comprises many species with a broad geographic range across tropical coastal
areas, including many species which have been shown elsewhere to be highly
vagile. Many species of the former set appear to have been lost from the
smaller islands. The island flora has been influenced by three sets of human
managers. Aboriginal use of the islands has been long-standing and probably
resulted in a fire regime which may have accentuated environmental patchiness.
Centuries of wet-season use of some islands by Macassan trepang-harvesters,
ending early this century, has apparently left few effects other than the
persistence of occasional small populations of an introduced food tree. In
contrast, European use of these islands has been minimal and fleeting, but is
associated with the introduction of most weeds.
The Big Ash forest, Wallaby Creek, Victoria— changes during one lifetime
Authors: Ashton D. H.
Published: September 2002

In 1949 the area of mature Eucalyptus regnans
F.Muell1 (the Big Ash) on the Hume Range, Victoria, was
a largely even-aged 230-year-old forest with a component of the overstorey
derived from a fire in 1851. Subsequent fires have resulted in patchy
regeneration where suitable gaps in the overstorey were present. In 1949 three
main types of the understorey were present: type A, mature
Pomaderris aspera; type B, dense immature
Pomaderris aspera; and type C, coppiced
Olearia argophylla and
Bedfordia arborescens. In type A, ground fern was patchy
and statistically correlated with patches of lower density
Pomaderris aspera. Over a period of 48 years the
eucalypt overstorey has been depleted by death and windthrow while understorey
trees and shrubs have been severely damaged by sporadic heavy snowfalls and
insect and fungal attack. The type A understorey is now showing signs of
changing to Olearia argophylla dominance and the cover
of ground fern and tree fern strata has doubled to more than 80% over
this period in spite of damage caused by infrequent, but severe, droughts. The
type B understorey is now mature and resembles type A, while the type C
understorey shows invasion by Pomaderris aspera and
regeneration of Olearia argophylla. No successful
establishment of E. regnans has occurred. The rainforest
in the gullies consists of alternating patches of forest and tree fern groves,
the latter, together with rotting logs and upthrown root balls, providing
niches for rainforest tree establishment. In swampy flats of
Leptospermum grandifolium on the plateau
Atherosperma moschatum is becoming increasingly
dominant. Atherosperma moschatum is also invading mature
understorey adjacent to riparian communities. This species and
Olearia argophylla may constitute the final stage of the
long secondary succession after fire in the Big Ash area. However, the Hume
Range is adjacent to drier foothills and plains to the north, west and south.
Whether the Big Ash will be spared from fire in future centuries is very
doubtful.
Effects of variation in fire intensity on regeneration of co-occurring species of small trees in the Sydney region
Authors: Morrison David A. , Renwick John A.
Published: September 2002

Fire is a common source of change for the plant species of Mediterranean-type
ecosystems, but little is known about the comparative effects of different
fire intensities. Accordingly, nine species of small tree
(Acacia binervia, Acacia implexa,
Acacia parramattensis,
Casuarina littoralis,
Casuarina torulosa, Hakea sericea,
Jacksonia scoparia,
Leptospermum trinervium,
Persoonia linearis) were studied 1 year after each of
two low-intensity prescribed fires and a high-intensity wildfire at a site in
the outer western region of the Sydney metropolitan area, south-eastern
Australia. All of the species except H. sericea proved
to be at least partly tolerant of the low-intensity fires (40–80%
of their stems surviving the fires), but only
C. torulosa, L. trinervium and
P. linearis were tolerant of the high-intensity fire
(20–30% stem survival). All of the fire-tolerant species had more
of their smaller stems killed by the fires, and the high-intensity fire killed
larger stems than did the low-intensity-fires. The size of surviving stems was
related to the fire-tolerance characteristics for these species, specifically
the presence or absence of insulating bark and epicormic or lignotuberous
buds, as well as stem height (preventing 100% leaf-scorch). Those
species with post-fire shoots at the stem base produced them when the upper
part of the stem had been killed, with variable response to the fire
intensities in the number of shoots produced. Those species with post-fire
epicormic shoots produced them if the stem was alive post-fire, usually with
fewer shoots produced after the high-intensity than the low-intensity fire.
The number of shoots produced was positively related to the size of the stem
for both fire intensities. These different sets of responses to the fire
intensities have important implications for the ability to predict community
responses to fire based on the study of only a few species, as well for the
long-term effects of prescribing a particular fire regime.
Monocotyledonous geophytes: comparison of California with Victoria, Australia
Authors: Parsons R. F.
Published: September 2002

Data on monocotyledonous geophytes from a recent Victorian flora are compiled
and compared with those from California and some other areas of mainly
mediterranean climate. Victoria's monocot geophyte diversity of 9%
places it with parts of South Africa and Western Australia in a group of much
higher diversity than California and Chile. The Victorian list is dominated by
orchids (all with tuberous roots) and that from California by Alliaceae,
Calochortaceae and Liliaceae, with bulbs being the predominant storage organ.
Only four families of the 17 involved have native species in both California
and Victoria. Most taxa in both areas are dormant in summer and grow during
the cool season. However, the Amaryllidaceae found in the Sonoran Desert and
the driest parts of Victoria are able to grow in the warm season in response
to summer rain.
An anatomical study of epicormic bud strand structure in Eucalyptus cladocalyx (Myrtaceae)
Authors: Burrows G. E.
Published: September 2002

Epicormic bud strands in Eucalyptus cladocalyx F.Muell.
extended from the pith to the outer bark. In large-diameter stems (30 cm
diameter, 2 cm bark thickness) the epicormic bud strands had their greatest
anatomical complexity at the level of the vascular cambium. At this level the
epicormic bud strand was about 3 mm wide × 5 mm high in transverse
section and within it were 22–40 radially arranged strips of cells of
meristematic appearance embedded in a mainly parenchymatous matrix.
Well-developed buds with leaf primordia and vascular connections were never
observed in intact trees, although when stimulated each meristem strip could
produce numerous bud primordia. Toward the bark surface the epicormic bud
strands became progressively simpler in structure. On the stem surface, the
position of the epicormic bud strand was shown by a number of adjacent small
protrusions which appeared to have no meristematic potential. From the outer
secondary xylem to the pith the bud strand usually became slightly smaller in
diameter and its cells, although nucleated, had thick lignified walls and the
meristem strips were much reduced or were not present. In most previously
investigated angiosperm tree genera epicormic shoots develop from suppressed
buds embedded in the bark. Eucalyptus appears to be unique in that suppressed
buds are not present in the bark and that each epicormic bud strand has the
potential to form numerous bud primordia when stimulated to do so.
Conservation and genetics in the fragmented monsoon rainforest in the Northern Territory, Australia: a case study of three frugivore-dispersed species
Authors: Shapcott Alison
Published: September 2002

Monsoon rainforest in the Northern Territory exists as an archipelago of tiny
patches thought to be previously more continuous but having had retracted to a
fragmented state by the Pleistocene. However, there is evidence of some more
recent rainforest expansion, and many species have seeds that are dipsersed by
small frugivores (birds and bats). Carpentaria acuminata
and Ptychosperma bleeseri are endemic to the Northern
Territory and Syzygium nervosum is endemic to the
Northern Territory within its Australian distribution.
Carpentaria acuminata and
S. nervosum are common through moist rainforest, but
P. bleeseri is rare, found in eight locations near
Darwin. All have frugivore-dispersed seeds. The three species were surveyed
across their geographic range to compare their population genetics. The
results from C. acuminata and
S. nervosum were analysed to investigate the
distribution of allelic diversity, the effect of patch size and isolation on
genetic diversity, and the effectiveness of seed dispersal by vagile
frugivores. Genetic diversity (expected heterozygosity) was correlated with
mean annual rainfall in both S. nervosum and
C. acuminata. Genetic diversity (alleles per locus,
percentage of polymorphic loci, expected heterozygosity) was also negatively
correlated with population isolation but not patch size in
C. acuminata. There was significant heterogeneity and
low gene flow among C. acuminata populations
(FST 0.379,
Nm = 0.39) but not among
S. nervosum populations, which had substantial evidence
of gene flow (FST 0.118,
Nm = 1.67). The distribution of rare alleles in
C. acuminata was consistent with the theory of
Pleistocene retraction to refugia. Ptychosperma bleeseri
was genetically uniform across all sites. Only four individuals differed in
their genotypes. The results suggest that the present populations originated
from a single founder population rather than having independently contracted
from a more extensive distribution. All three species had evidence of some
more recent population expansion.
How well do phylogenetic studies inform the conservation of Australian plants?
Authors: Hopper Stephen D.
Published: September 2002

Conservation of Australian plants depends on a spectrum of activities from
descriptive and experimental biological studies to active management and
restoration of wild ecosystems by local communities who value their native
biota. On the basis of the premise that available resources for conservation
will not allow for all threatened biodiversity to be saved, some systematists
and conservation geneticists argue that phylogenetic relationships should be
used to set conservation priorities. The principle advocated is that
characters, not species number, should become the currency of conservation,
that cladistic analysis of phylogenetic pattern provides a predictive means of
modelling the underlying distribution of characters among taxa, and that
priority should be given to that subset of taxa with the greatest number of
character states.
This approach has been applied for some time in the conservation of genetic
resources within species (e.g. Eucalyptus caesia), and
has been an extra impetus for action with taxonomically isolated endangered
species such as the recently discovered araucarian Wollemi pine
(Wollemia nobilis). However, most plant conservation
activity in Australia has paid little heed to phylogenetic relationships.
Degree of threat has been a driving motivation, with endangered species
receiving legislative and management attention irrespective of their
systematic relationships. Moreover, the current revolution in understanding
plant phylogeny associated with DNA sequence studies highlights the need for
caution in accepting results of morphologically based analyses. A series of
studies on the kangaroo paw and bloodroot family Haemodoraceae highlights this
cautionary tale.
The derivation of phylogenetic principles relevant to ecosystem and landscape
processes is a new field of some promise to conservation managers. An
understanding of the Gondwanan origins and landscape evolution of the
south-west Australian flora provides a useful case study. Scaling up
phylogenetic knowledge of genetic resources within species, and of the
evolutionary relationships of taxa to an integrated overview of best
management practices for all taxa at the local landscape level, is perhaps the
most effective contribution phylogeneticists might make to help conserve
Australian plants.
An analysis of mating structure in populations of the annual sea rocket, Cakile maritima (Brassicaceae)
Authors: Thrall Peter H. , Young Andrew G. , Burdon Jeremy J.
Published: September 2002

Cakile maritima is an introduced brassicaceous annual
plant, now occurring widely along the Australian coastline. While variable,
populations of C. maritima often show high levels of
infection by a fungal pathogen, Alternaria brassicicola.
As part of a larger metapopulation study of host–pathogen dynamics in
this system, an isozyme survey of seven populations of
Cakile was carried out along the south coast of New
South Wales to investigate mating structure. Given the possibility of
self-incompatibility, a glasshouse crossing experiment was also carried out to
investigate the potential for selfing. The results from the crossing study
showed that C. maritima is basically an obligate
outcrosser, but that self-compatible individuals also occur at low frequency,
providing some flexibility in the mating system. Similarly, analysis of the
isozyme data showed a preponderance of cross fertilisation, but with
significant low levels of selfing in two populations. There were no
correlations between outcrossing rates and population size or density,
although there was evidence of restricted mating at the individual level (low
paternal diversity within seed from a given mother). However, this did not
translate into biparental inbreeding, even in very small populations, most
likely due to incompatibility leading to negative assortative mating.
Responses of native woody taxa in Banksia woodland to incursion of groundwater and nutrients from bordering agricultural land
Authors: Grigg Alasdair M. , Pate John S. , Unkovich Murray J.
Published: September 2002

Effects of incursion of water and nutrients from agricultural land on
adjoining native Banksia woodland were examined near
Moora, Western Australia, by using a 100-m-wide belt transect from the paddock
edge into virgin bush. Transect zones 0–20, 20–50 and
100–300 m inwards were designated as ‘hedge’,
‘transition’ and ‘inner bush’, respectively. Numbers
of species of native woody taxa increased from 28 to 42 and plant densities
increased from 2200 to 14 900 plants per hectare from hedge through transition
to inner bush, while collective total standing biomass (above and below
ground) of woody species decreased from 157 to 32 t dry matter per hectare.
Data for nutrient contents of this total biomass indicated that total nutrient
loads in respect of calcium, potassium, sulfur, phosphorus, magnesium, zinc,
copper and sodium were closely related to relative amounts of biomass in the
three zones, but hedge vegetation was appreciably enriched in nitrogen but
depleted in manganese and chlorine compared to inner bush. Diversity indices
indicated differential responses of species to agricultural influence. The
dominant tree species, Banksia prionotes, represented
91, 87 and 58% of the total biomass of woody taxa in hedge, transition
and inner bush, respectively. Growth ring analyses of basal trunk xylem
indicated that this seeder species had recruited after a hot burn in 1963
coincident with land clearing. Since then, annual trunk-area increments in
hedge trees have been consistently much greater than in transition and bush.
Net annual productivities, dry matter allocation profiles and current leaf
areas of B. prionotes showed that the average hedge tree
weighed 167 kg total dry matter and was currently increasing at 11.9 kg per
year and was in the process of achieving net dry matter gains of 420 g
m–2 of leaf surface. Comparable figures for
transition trees were 61 kg, 4.7 kg per year and 360 g
m–2, for inner bush trees 12.7 kg, 1.1 kg per year
and 230 g m–2. Results are related to recent
studies on Banksia woodlands and general information on
ecotones and their attributes.
Syntheses of the Seco Benzyltetrahydroisoquinoline Alkaloids Polysignine and Methoxypolysignine
Authors: Nimgirawath Surachai
Published: September 2002

The structures previously assigned to the seco benzyltetrahydroisoquinoline
alkaloids polysignine (1) and methoxypolysignine (2) have been confirmed by
total syntheses in which the key step involved cleavage of the C1–N
bonds in the corresponding
N-methylbenzyltetrahydroisoquinolines.
Ultraviolet Absorption and Fluorescence Studies of 1-Methyl-2(1H)-Pyridinimine and Derivative in Polar and Non-Polar Solvents
Authors: Traore Hassimi , Saunders Michael , Blasiman Scott
Published: September 2002

The ultraviolet (u.v.) and fluorescence spectra and relative fluorescence
intensities of 1-methyl-2(1H)-pyridinimine (1-MIP) and
1,2-dimethylpyridinimine (2-MIP) were measured in several solvents at room
temperature. The solvents’ effect on the absorption and fluorescence
spectra of MIP indicates that the ππ* transition shifts to higher
energies (shorter wavelengths) are due to solvents’ interactions and the
formation of the pyridinium cation. One major difference in the u.v. and
fluorescence spectra is the small relative intensity in non-polar solvents.
This was attributed to the proximity effect of ππ* and nπ*
states which can lead to vibronic interactions, and to distortions of the
excited-state potential surfaces. In polar solvents, however, these two states
are shifted in energy due to solvent–solute interactions, which decrease
the energy of the potential surface.
Naphtho[2,3-c]furan-4,9-dione and a Further Exploratory Approach to the Ring System of Ventilone A
Authors: Karichiappan Kalanithy , Wege Dieter
Published: September 2002

1,4-Dimethoxy-2,3-didehydronaphthalene (10), generated by the
dehydrobromination of 2-bromo-1,4-dimethoxynaphthalene (9), was trapped with
furan and 2-methylfuran, and the resulting adducts were converted into
naphtho[2,3-c]furan-4,9-dione (1) and
1-methylnaphtho[2,3-c]furan-4,9-dione (19)
respectively. An attempt to extend this procedure to the synthesis of
ventilone A (2) failed when the adduct (31), derived from
6,7-methylenedioxy-1,4,5,8-tetramethoxy-2,3-didehydronaphthalene (30) and
2-methylfuran, could not be oxidizedselectively.
Crystal Structures of the ('Maximally') Hydrated Scandium Halides, ScX3.nH2O (X = Cl, Br, I)
Authors: Lim Kevin C. , Skelton Brian W. , White Allan H.
Published: September 2002

Low-temperature single-crystal X-ray structure determinations are recorded for
the (‘maximally’) hydrated scandium(III) trihalides,
ScX3.nH2O (X
= Cl, Br, I). The chloride and bromide are isomorphous heptahydrates
(n =7),
ScX3.7H2O
=[Sc(OH2)7]X3,
monoclinic, space group P2/n,
a ~ 7.6, b ~ 7.7,
c ~ 9.6 Å, β ~ 99˚,
Z = 2, R 0.051, 0.039 for
No 1253, 1339
‘observed’ (F > 4σ
(F)) reflections, respectively, the metal atom disposed
in a homoleptic environment of seven water molecule oxygen atoms arranged in
an essentially pentagonal-bipyramidal disposition, site symmetry 2,
Sc–O(axial) 2.095 Å, Sc–O(eq)
2.157(3)–2.209(4) Å. The iodide is an octahydrate,
ScI3.8H2O
=[Sc(OH2)7]I3.H2O,
monoclinic
P21/c,
Z = 4, R 0.022 for
No 3243; the seven-coordinate
metal atom environment here is well distorted from the pentagonal-bipyramidal
norm, the largest angle in the coordination sphere being 162.4(1)˚,
subtended by Sc–O 2.109(3), 2.128(3) Å, the remaining Sc–O
ranging between 2.157(3)–2.219(3) Å.
Atropisomerism of 2,2'-Binaphthalenes
Authors: Baker Robert W. , Brkic Zinka , Sargent Melvyn V. , Skelton Brian W. , White Allan H.
Published: September 2002

The synthesis of diastereo-enriched substituted
(4S)-4-isopropyl-2-(2,2′-binaphthalen-1-yl)-4,5-dihydrooxazoles
from substituted 2-naphthalenylmagnesium bromides and
(4S)-4-isopropyl-2-(2-methoxynaphthalen-1-yl)-4,5-dihydrooxazole (4) and
(4S)-4-isopropyl-2-(2,3-dimethoxynaphthalen-1-yl)-4,5-dihydrooxazole
(5) is described. The product oxazolines were converted into a number of
derivatives and the free energy barriers to internal rotation of several of
these derivatives were determined. The determination of the X-ray crystal
structures and the c.d. spectra of
(S,1S)-N-[2-hydroxy-1-(isopropyl)ethyl]-3-methoxy-1′,N-dimethyl-2,2′-binaphthalene-1-carboxamide
(22) and
(R,4S)-4-isopropyl-3-methyl-2-(1′,2′,4′-trimethyl-2,2′-binaphthalen-1-yl)-4,5-dihydrooxazolium
iodide (38) allowed the assignment of the absolute configurations of all the
synthetic 2,2′-binaphthalenes by comparison of their c.d. spectra
with those of compounds (22) and (38).
Intramolecular Hydroamination of 1,4,7-Tri(pent-4'-yn-1'-yl)-1,4,7-triazacyclononane: Formation of an Azoniaspiro-[4.8]-tridecane
Authors: Baker Murray V. , Brown David H. , Skelton Brian W. , White Allan H.
Published: September 2002

In methanol solution,
1,4,7-tri(pent-4′-yn-1′-yl)-1,4,7-triazacyclononane
undergoes an intramolecular hydro-amination reaction to form an
azoniaspiro[4.8]tridecane cation,
1-methylidene-8,11-di(pent-4′-yn-1′-yl)-8,11-diaza-5-azoniaspiro[4.8]tridecane.
The azoniaspiro[4.8]tridecane cation, as its tetraphenylborate salt,
has been characterized spectroscopically in solution and by X-ray studies in
the solid state. Reactions of the azoniaspiro[4.8]tridecane that
lead to other products are also discussed.
Total Synthesis of the Pentacyclic Diterpenoid Tropone Hainanolidol
Authors: Frey Barbara , Wells Adam P. , Roden Frances , Au Ty Duong , Hockless David C. , Willis Anthony C. , Mander Lewis N.
Published: September 2002

The total synthesis of the unusual diterpenoid tropone, hainanolidol (1),
discovered in the bark of the yew species,
Cephalotaxus hainanensis, has been completed in 26 steps
from 3,5-dimethylanisole. The intramolecular cyclopropanation reaction of the
aryl ring in (30) by means of the rhodium mandelate-catalysed reaction of the
diazoacetyl function was used to assemble the 5/7 ring system of (31), at
the same time elaborating a cycloheptatriene moiety that could be transformed
subsequently to the tropone functionality in the target molecule. While
removing the acetal protecting group from (31) an unexpected
Mukaiyama–type aldol process was induced by ZnBr2,
affording (32), the structure of which was determined by X-ray analysis. With
greater care, the aldehyde (33) could be obtained and the desired carbocyclic
ring system completed by means of a base-catalysed aldol reaction with the
newly formed hydroxyl being employed subsequently in the formation of the
σ-lactone function in (35). Desilylation, reduction of the C-10 carbonyl
function and brief exposure to acid finally afforded (1). This last step took
advantage of the stability of the tropylium ion (40) to provide a
‘thermodynamic sink’ for the reaction outcome. The synthesis of
(1) also constitutes a formal synthesis of the troponoid ether,
harringtonolide (2), since this compound had been obtained previously from (1)
by means of a transannular oxidation process. Methodology for the assembly of
the tropone moiety in (1) and (2) was modelled on the simpler bi- and
tricyclic systems, (13) and (22), respectively.
Quantitative Determination of Sodium Metatungstate Speciation by 183W N.M.R. Spectroscopy
Authors: Smith Bradley J. , Patrick Vincent A.
Published: September 2002

The speciation and equilibria of sodium metatungstate,
Na6[H2W12O40],
has been determined by a combination of 183W n.m.r.
spectroscopy and gravimetry over the p[H] range 4.5–10.0. The
use of n.m.r. spectroscopy allowed the direct observation of polytungstate
anions in aqueous solution and high concentration (0.25 mol
l–1). Sodium metatungstate, with the progressive
addition of base, was found to decompose to paratungstate A,
[W7O24]6–.
Paratungstate A then slowly converted to paratungstate B,
[H2W12O42]10–.
The kinetics of equilibrium was found to be slow, requiring up to 8 months to
stabilize. With the addition of further base paratungstate B decomposed to
orthotungstate, WO42–.
Logarithmic constants (logK) for these transformations
were determined as 195, 20 and 118, respectively. The solubility product for
sodium paratungstate B was determined to be 6.89 ( 0.80)
10–6.
Polymorphism and Phase Transitions in Bis(glycinato)copper(II). A Powder Diffraction Study
Authors: Hunter B. A. , Moussa S. M. , Fenton R. R. , Kennedy B. J.
Published: September 2002

Powder diffraction methods have been used to establish the structures of four known polymorphs of bis(glycinato)copper(II). The two cis-modifications are orthorhombic, and the two trans-complexes are monoclinic. Refinements of the structures, including the location of the hydrogen/deuterium atoms have been achieved utilizing Rietveld analysis of powder data. The cis-monohydrate complex crystallizes in the space group P212121 with lattice parameters a 10.8053(3), b 5.2101(1), and c 13.4983(4) �. Upon dehydration, contraction along the a- and c-axes and elongation of the b-axis is observed. The anhydrous cis-complex also crystallizes in the space group P212121 with lattice parameters a 10.0673(7), b 5.3152(4), and c 13.212(1) �. The trans-hydrated complex crystallizes in the space group I2/a with lattice parameters a 14.8218(3), b 5.2321(1), and c 9.6408(2) �, and β 87.243(1)°. Dehydration of the complex affords the anhydrous modification which crystallizes in the space group P21/c with lattice parameters a 7.0831(6), b 5.1459(4), and c 9.4431(9) �, and β 107.506(4)°. In all four modifications a network of hydrogen bonds stabilizes the complex. This study illustrates the current capabilities of powder diffraction techniques.
The Structure and Magnetic Properties of the Two-Dimensional Di-Pyrazine Bridged Polymers M(pz)2Br2 (M = FeII, CoII, NiII)
Authors: James M.
Published: September 2002

The polymeric compounds M(pyrazine)2Br2 [M = Fe (1), Co (2), and Ni (3)] have been synthesized by the addition of a solution of pyrazine in methanol to a methanolic solution of the anhydrous metal bromide. The crystal structures of (1)-(3) were determined using powder synchrotron and neutron diffraction data and were found to be isostructural. The structures consist of pseudo-octahedral units, doubly linked by pyrazine ligands to form two-dimensional sheets. Magnetic susceptibility data were recorded for each complex down to 5 K and reveal paramagnetic behaviour at high temperatures and antiferromagnetic interactions at low temperatures. Comparison of the structures and magnetism of these and other M(pz)2X2 compounds highlight the relative importance of the canting of the pyrazine ligands on the strength of the magnetic exchange.
Current Chemistry: Malleable Coordination Networks
Authors: Batten Stuart R. , Murray Keith S.
Published: September 2002

Manuscript received: 24 September 2001.
Final version: 9 November 2001.
Current Chemistry: Characterization of Thin-Film Surfaces and Interfaces Using Neutron Reflectometry
Authors: James Michael
Published: September 2002

Neutron reflectometry has become an increasingly important technique in the
characterization of thin-film surfaces and interfaces. Recent advances in
instrumentation, experimental design, sample environments and methods of data
analysis now make it possible to obtain an angstrom-precision depth profile of
the film composition. Neutrons are non-destructive and highly penetrating
which makes them ideal probes for the study of buried interfaces as well as
surfaces under a wide range of extreme environments. Isotopic H/D
substitution (particularly in colloidal, polymeric or biological systems)
provides a unique tool for selectively labelling different components of
complex planar architectures. The fundamental aspects of neutron reflectometry
are discussed, and the utility of this technique is illustrated by a review of
several recent studies.
Current Chemistry: Separation and Recovery of Gold and Other Metals Using Conducting Polymers
Authors: Price William E. , Ralph Stephen F. , Wallace Gordon G.
Published: September 2002

A variety of metal ions including alkali metals and transition metals can be
transported across conducting polymer membranes, but only when an appropriate
electrochemical stimulus is applied. This paper summarizes recent work in this
area, and also describes how conducting polymer RVC composite materials (RVC
= reticulated vitreous carbon) can be used to recover gold from
solutions containing
[AuCl4]-with a high
degree of efficiency and selectivity.
Manuscript received: 2 November 2001.
Final version: 19 December 2001.
Chemical Relationships between the Sea Hare Aplysia parvula and the Red Seaweed Laurencia filiformis from Tasmania
Authors: Jongaramruong J. , Blackman A. J. , Skelton B. W. , White A. H.
Published: September 2002

One new 5-acetoxy-2,10-dibromo-3-chloro-7,8-epoxy-α-chamigrene (1) and three known sequiterpenes, namely 2,10-dibromo-3-chloro-7-chamigrene (2), deoxyprepacifenol (3), and pacifenol (4), were isolated from both the sea hare Aplysia parvula and the red seaweed Laurencia filiformis. On the other hand, pentadecanal and its aldol product (E)-2-tridecyl-2-heptadec-2-enal (6) were only separated from L. filiformis while the previously known fimbrolide (5) from Delisea sp. and the known purple pigment, aplysioviolin (7), were isolated only from the sea hare A. parvula. The structure of aplysioviolin (7) has been revised and the nuclear magnetic resonance spectra of (2)�fully assigned for the first time. A single crystal X-ray study is reported for (1). The brine shrimp bioassay showed 90% mortality using pacifenol, at a concentration of 23 μg/mL in seawater after 24 h as the strongest activity among all the test compounds (1)-(4) and (7).
Synthesis of Structurally Simplified Aureolic Acid Aglycone-C-D-E Trisaccharide Analogues
Authors: Roush W. R. , Powell N. A. , James R. A.
Published: September 2002

Syntheses of aureolic acid analogues (5) and (6) with (2S)- and (2R)-acyloin stereochemistry, respectively, are described. The synthesis of (5) utilizes a `C + DE' glycosidation sequence, whereas analogue (6), with unnatural (2R)-acyloin stereochemistry, was synthesized by a sequence in which the entire C-D-E trisaccharide was introduced in a single step. While these syntheses provided sufficient quantities of the two aureolic acid analogues for use in studies of Mg2+ complex formation and deoxyribonucleic acid (DNA) binding, this work also highlights certain limitations in the use of 2-thiophenyl glycosyl donors for synthesis of 2-deoxy-β-glycosides. Specifically, difficulties were encountered in the identification of a protecting group for the aglycone C8 phenol that is fully compatible with the conditions required for reductive removal of the thiophenyl substituents after completion of the glycosidation sequence. Sensitivity of the C2 acyloin stereocentre to the conditions required for deprotection of a phenolic acetate ester are also highlighted in the syntheses of (5), and especially of (6).
Towards the Synthesis of Aureolic Acid Analogue Conjugates: Synthesis and Glycosidation Reactions of 3-O-Acetyl-4-azido-2,4,6-trideoxy-L-glucopyranose Derivatives
Authors: Roush W. R. , James R. A.
Published: September 2002

A stereoselective synthesis of 3-O-acetyl-4-azido-glucopyranose (6) is described. The derived anomeric acetate (13), and especially the thioglycoside (14), are demonstrated to be good donors for synthesis of α-glycosides of (6). Donor (14) was used in the synthesis of trisaccharide (21), which is targeted for use in the synthesis of the aureolic acid trisaccharide conjugate analogue (5).
Trivalent Cluster Mannosides with Aromatic Partial Structure as Ligands for the Type 1 Fimbrial Lectin of Escherichia coli
Authors: Röckendorf N. , Sperling O. , Lindhorst T. K.
Published: September 2002

Mannose-specific adhesion of E. coli bacteria to their host cells is mediated by so-called type 1 fimbriae containing lectin domains present on the type 1 fimbrial FimH protein. The crystal structure of a FimH-FimC(chaperone) protein complex revealed a number of amino acids in the carbohydrate binding site with aromatic side chains. This finding is in keeping with earlier results showing high inhibitory potencies of aryl mannosides when tested as inhibitors of type 1 fimbriae-mediated bacterial adhesion. In addition, clustering of mannosyl moieties also led to favourable effects, as in the case of trivalent cluster mannosides such as (1). In order to combine both, i.e. the clustering approach and the advantage of an aromatic moiety, the herein presented study has emphasized the synthesis of three cluster mannosides (2), (3), and (4), as ligands for the type 1 fimbrial lectin, which contain a phenyl partial structure in different proximity to the core of the molecule. The inhibitory potencies of the new cluster mannosides were determined in enzyme-linked immunosorbent assays (ELISAs).
The Intricate Pathway of Starch Biosynthesis and Degradation in the Monocellular Alga Chlamydomonas reinhardtii
Authors: Ball S. G.
Published: September 2002

Starch and glycogen define the two most widespread storage polysaccharides found in living cells. Both consist of α -1,4 linked and α -1,6 branched glucans but differ considerably in their structure and physicochemical properties. Because of its complex semi-crystalline organization, starch poses a particular challenge to understand the basis of its synthesis through hydrosoluble enzymes. This review summarizes the authors progress in understanding starch biosynthesis through the use of a unicellular model plant system. Comparative biochemistry of starch synthesis in the green alga Chlamydomonas reinhardtii and of glycogen synthesis in bacteria point to both duplication and specialization of the set of enzymes responsible for formation of the two types of glucosyl linkages. In addition, enzymes previously thought to be solely involved in polysaccharide catabolism turn out to be either also or exclusively involved in starch biosynthesis.
End-Group Analysis of Polymers by Electrospray Ionization Mass Spectrometry: 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one Initiated Free-Radical Photopolymerization
Authors: Vana P. , Davis T. P. , Barner-Kowollik C.
Published: September 2002

End-group analysis of poly(methyl acrylate) and poly(dicyclohexyl itaconate) initiated by 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (MMMP) has been performed by electrospray ionization mass spectrometry (ESI-MS). MMMP has been found to fragment into two radicals that are near-equally capable of initiating free-radical polymerization processes. The present study indicates the occurrence of significant termination by disproportionation in the polymerization of methyl acrylate. Additionally, it has been demonstrated that dicyclohexyl itaconate undergoes termination by disproportionation almost exclusively.
Rhenium Diamino Dithiol Complexes. III. Lipophilic Ligands for Endotherapeutic Radiopharmaceuticals
Authors: Jackson Timothy W. , Kojima Masaharu , Lambrecht Richard M.
Published: September 2002

The chemistry and physical properties of a series of rhenium diamino dithiol
(dadt) complexes are described. Liposolubility was enhanced by
N-substitution of alkyl chains of
C1–C14 length on one ligand
structure, with longer chain lengths showing the higher solubility, but with a
reduction of radiolabelling yield with 99mTc and
186Re. Among the ReV=O
[dadt] complexes synthesized, we found that
2,2,9,9-tetramethyl-4-N-alkyl-4,7-diaza-1,10-decanedithiol
(alkyl = C1–C10)
resulted in stable and lipiodol-soluble complexes. Biological characteristics
of the C6 ligand labelled with
99mTc and 186Re were compared, and
indicated that the complexes behaved in a similar manner in rodents. The dadt
ligands in combination with 188Re or
186Re and fatty acid oils merit further consideration as
endotherapeutic radiopharmaceuticals for treatment of hepatoma and metastatic
liver cancer.
2,7-Dimethylthiazolo[4,5-d]pyradazine-4-(5H)-thione: A Corticotrophin-Releasing Hormone Type 1 Receptor Agonist
Authors: McCluskey Adam , Finn Matthew , Bowman Maria , Smith Roger , Keller Paul A.
Published: September 2002

Thiazoles, including
2,7-dimethylthiazolo[4,5-d]pyradazine-4-(5H)-thione
(4b) and the corresponding
5-phenylthiazolo[4,5-d]pyradazine-4-methylthiol (5a), were
synthesized as part of an ongoing investigation into corticotrophin-releasing
hormone (CRH) type 1 receptor activity. Subsequent screening indicated the
successful discovery of receptor agonists. Assay results indicated a 52 and
3% increase in β-endorphin release after the administration of 100
M (4b) and (5a), respectively. It is believed that this represents the first
evidence of this class of compounds displaying CRH type 1 receptor agonist
activity.
Anticipating Molecular Polarity. II. A Graph-Theoretical Approach to Hückel pi-Polarizations of Non-Alternant Monocycles and Bicycles
Authors: Langler Richard Francis
Published: September 2002

The problem of simply, conveniently anticipating HÜckel-level
polarization of non-alternant monocycles and bicycles has been solved with the
aid of a new type of graph, i.e. the norgraph. Along with appropriate
equations and newly devised sipoles, norgraphs provide an analytical procedure
which can also be applied to planning structural modifications that will alter
topologically induced polarity in a rational way. The accompanying paper
outlines procedural changes necessary to anticipate PM3 calculated topological
polarization of non-alternant monocycles and bicycles.
Cyano-Bridged Bimetallic Complexes of Copper(II) with Nitroprusside. Crystal Structure of [Cu(H2NCH2CH(NH2)CH3)2Fe(CN)5NO] . H2O
Authors: Smékal Zdenek , Trávnícek Zdenek , Marek Jaromír , Nádvornik Milan
Published: September 2002

Five new complexes of compositions
[Cu(1,2-pn)2Fe(CN)5NO]·H2O
(1,2-pn = propane-1,2-diamine) and
[Cu(L)Fe(CN)5NO]·xH2O
(L = tmen
(N,N,N′,N′-tetramethylethane-1,2-diamine),
x = 0.5; L = trimeen
(N,N,N′-trimethylethane-1,2-diamine),
x = 1; L = dien
(N-(2-aminoethyl)ethane-1,2-diamine),
x = 0; L = medpt
(N-(3-aminopropyl)-N-methylpropane-1,3-diamine),
x = 2) have been isolated from the reaction
mixture of
Cu(ClO4)2·6H2O
(or CuCl2·2H2O), the amine
and Na2
[Fe(CN)5NO]·2H2O
in water. The complexes have been characterized by infrared and
ultraviolet–visible spectroscopies, and magnetic measurements.
Single-crystal X-ray structural analysis revealed that the
[Cu(1,2-pn)2Fe(CN)5NO]·H2O
complex assumes a cyanide-bridged binuclear structure in which iron(II) is
six-coordinated by five cyanide ligands and one nitrosyl group (the nitrosyl
group lies cis to the bridging cyanide group), while copper(II) is
five-coordinated by two propane-1,2-diamine ligands and a bridging cyanide
ligand in a distorted tetragonal pyramidal arrangement.
New and More Potent Antifungal Disulfides
Authors: Baerlocher Felix Jakob , Baerlocher Mark Otto , Langler Richard Francis , MacQuarrie Stephanie Lee , Marchand Maurice Emile
Published: September 2002

From a design principle described in an earlier paper, a new series of
substituted aryl methyl disulfides have been prepared and tested against
Aspergillus niger and
Aspergillus flavus. Methyl
p-nitrophenyl disulfide is more potent (by an order of
magnitude) than the fungitoxic natural product
(CH3SCH2S)2.
With the present rationale in hand, one can anticipate which Polycarpamine is
an effective antifungal agent.
Synthesis and Structural Studies of Strontium-Substituted Tricalcium Aluminate Ca3-xSrxAl2O6
Authors: Prodjosantoso A. K. , Kennedy Brendan J. , Hunter Brett A.
Published: September 2002

A series of 27 oxides of the type
Ca3–xSrxAl2O6,
3 £ x £ 0, were prepared as polycrystalline
powders. The compounds are isostructural with
Ca3Al2O6,
space group
Pa3–,
and their structures were refined from powder neutron and/or X-ray
diffraction data by using the Rietveld method. The evolution of Ca/Sr site
occupancies, with x, was determined. It was found that
the Ca and Sr cations display strong site selectivity, the smaller Ca
2+ cations preferentially occupying the
six-coordinate sites. The relationship between the observed structures and the
reactivity of
Ca3Al2O6 in
Portland cement is discussed.
Are Polarized Cyclobutadienes Non-Aromatic?
Authors: Frederiksen Mathias Ugelstad , Langler Richard Francis , Watson Keith Jeffery , Penwell Andrea , Darvesh Katherine Valenta
Published: September 2002

A series of non-alternant cyclobutadienes, both hydrocarbon and
heteroatom-substituted, are examined by means of PM3 semiempirical molecular
orbital calculations. The results show that even very substantial polarization
has no simply predictable effect on antiaromatic character as measured by the
singlet–triplet energy gap. MP2 calculations on selected hydrocarbons
lead to the same conclusion.