bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser production of gas phase complexes of metal α‐aminophosphonic acid mixtures and their role in chiral recognition
Authors: Paladini A. , Calcagni C. , Palma T. Di. , Satta M. , Speranza M. , Scuderi D. , Laganà A. , Fago G. , Guidoni A. Giardini
Published: March 2007

Clusters between first‐group metal ions and chiral α‐aminophosphonic acids have been readily generated by Pulsed Laser Ablation (PLA) and by Electrospray Ionization (ESI) and their fragmentation investigated by mass spectrometry. The complexes studied have the general formula , where Me(I) is H, Li, Na, or K, C is (R)‐(—)‐(1-aminoethyl) phosphonic acid (ER) and (S)-(+)-(1-aminoethyl) phosphonic acid (ES), (1R)-(+)-(1-amino-2-methylpropyl) phosphonic acid (PR) and (1S)-(—)-(1-amino-2-methylpropyl) phosphonic acid (PS), (1R)-(-)-(1-amino-hexyl) phosphonic acid (HR) and (1S)-(+)-(1-amino-hexyl) phosphonic acid (HS), o-phospho-L-serine (SS) and o-phospho-D-serine (SR), and L is a reference α‐aminophosphonic acid
(E, P, H or S) of defined configuration. Collision induced dissociation (CID) of diastereomeric complexes leads to fragmentation patterns characterized by abundance ratios which depend upon the configuration of solute C. These different spectral features were correlated to the different
stability of the diastereomeric and complexes in the gas phase.
Sol‐gel niobium pentoxide coatings: Applications to photovoltaic energy conversion and electrochromism
Authors: Aegerter Michel A. , Schmitt Michael , Guo Yeping
Published: March 2007

In the last decade the sol‐gel process became a promising method to synthesize materials in
form of coatings, nanoscale powders and porous systems. Several products or devices made with such a
process already exist on the market. This paper briefly reviews the state of the art in the development of
electrochromic coatings and devices and nanocrystalline solar cells achieved during the last decade using
sol-gel derived pure and doped niobium pentoxide.
Ultrafast studies of electron injection in Ru dye sensitized SnO2 nanocrystalline thin film
Authors: Bauer Christophe , Boschloo Gerrit , Mukhtar Emad , Hagfeldt Anders
Published: March 2007

By using two‐color femtosecond transient absorption spectroscopy, we have measured the
electron injection rate for bis(tetrabutylammonium) cis di(thiocyanato) bis (2,2’‐bypiridine‐4,4’ carboxylic
acid)Ruthenium (II) dye (called N719) into SnO2 nanocrystalline thin films. The electron injection rate has
been measured by monitoring the formation of the dye oxidized state and the arrival of electrons in the
conduction band. Dynamics of electron injection are multiexponential (0.2, 4 and 130 ps) and are therefore
slower than the N719‐ZnO or N719‐TiO2 systems. The photocurrent action spectrum of N719‐SnO2 shows a quantum efficiency of 0.65 at 530 nm proving that efficient charge separation can take place despite of the
relatively slow electron injection rate.
Computer simulation of photoinduced molecular motion and reactivity
Authors: Garavelli Marco , Bernardi Fernando , Roob Michael A. , Olivucci Massimo
Published: March 2007

The use of the computer to simulate light induced chemical processes has given access to
a detailed description of the molecular motion and mechanism underlying the reactivity of organic and
bio‐organic chromophores. Thus, different computational strategies and tools can now be operated like
“virtual spectrometers” to characterize the photoinduced molecular deformation and reactivity of a given
chromophore. Furthermore, a systematic computer investigation of a wide range of photochemical organic
reactions during the last decade, has lead to novel concepts that allow the chemist to formulate the mechanism
of a photochemical reaction in a rigorous way and with a language which is familiar to chemists.

In this review we will revise some basic mechanistic concepts which have emerged in the novel field of
computational photochemistry. These comprise the concept of conical intersection funnels, photochemical
paths, path branching and selectivity. Recent work in the field of biological photoreceptors has demonstrated
that computational chemistry can be successfully applied to photobiological problems. Here we will revise the
results of the photoisomerization path mapping of the protonated Schiff base of retinal, the chromophore of
rhodopsin proteins. These studies have produced the “two‐state two‐mode model” which provides a description
of the photon‐induced molecular motion in the isolated retinal chromophore. Such model represents
a substantial revisionof the previous models for the primary event invisioninan imals and light driven
proton‐pumping in halobacteriae.
Direct phototransformation of aromatic pesticides in aqueous solution
Authors: Boule P. , Meunier L. , Bonnemoy F. , Boulkamh A. , Zertal A. , Lavedrine B.
Published: March 2007

The photochemical behaviour of many aromatic pesticides (mainly herbicides) are compared and
the main reactions are separated in three different classes: 1‐ reactions involving carbon‐halogen bond; 2 ‐
other reactions involving the aromatic ring; 3 ‐ reactions of the aliphatic moiety. It appears that the nature of
the substituents and their relative positions on the ring play a major role in the orientation of the reaction. The
molecular and ionic forms of ionisable molecules may have different photochemical behaviour. A wavelength
effect is observed with some compounds. The case of mecoprop [2‐(4‐chloro‐2‐methylphenoxy)‐propanoic
acid] is presented as an example.

The irradiation of herbicides in aqueous solution may lead to the formation of photochemical intermediates
more toxic to microorganisms than the initial substrate.
Kinetics of photocatalytic decomposition of Fenuron over TiO2 in aqueous solution
Authors: Brahmia Ouarda , Boulkamh Abdelaziz , Sehili Tahar , Aguer Jean-Pierre , Richard Claire
Published: March 2007

The kinetics of the photocatalytic degradation of Fenuron (3‐phenyl‐1,1‐dimethylurea) in aqueous
suspension of several semiconductors irradiated at 365nm has been investigated. The kinetics of the
reaction is well described by the Langmuir‐Hinshelwood model showing that the degradation reactions occur
on the semiconductors particles surface. The primary photoproducts were identified by RMN and GC/MS.
The main initial reaction is hydroxylation in ortho and para position with respect to the urea function. The
rate of the photocatalytic degradation increases upon addition of small amounts of hydrogen peroxide, but
is slightly reduced by chloride ions.
Suggested terms and definitions in photocatalysis and radiocatalysis
Authors: Serpone N. , Emeline A. V.
Published: March 2007

This document has two principal goals. First, it summarizes some of the issues that pertain to
the complexities encountered in photocatalysis. Secondly, it presents suggested terms and definitions proposed
to describe those phenomena, which fall under the umbrella of “photocatalysis” and “radiocatalysis”.
A distinction is made between the different phenomena that are related to either or both photochemistry
and photocatalysis, and to radiation chemistry and radiocatalysis. Consistent definitions of terms in these
areas are given. Definitions of important parameters that describe photocatalytic and radiocatalytic phenomena
quantitatively are also proposed. As with the related Glossary of Terms in Photochemistry, this
document is a dynamic working document to provide the base for lively discussion and debate by the interested
community. The terms and definitions will no doubt need to be revisited from time to time as
the fields of photocatalysis and radiocatalysis progress and new discoveries reported. Some of the terms
used in photochemistry are also given for completion, either verbatim or modified to address the issues
of photocatalysis.
Gelation in free‐radical crosslinking copolymerization; fast transient fluorescence study
Authors: Pekcan Ö. , Kaya D.
Published: March 2007

The fast transient fluorescence (FTRF) technique was used to study the sol‐gel phase transition
in free‐radical crosslinking copolymerization (FCC) in two different monomeric systems. Pyrene (Py) was used as a fluorescence probe for the in situ polymerization experiments. The fluorescence lifetimes of Py
from its decay traces were measured and used to monitor the gelation process. Monomer consumption
profiles were determined during gelation process using Stern‐Volmer model. Gelations were performed at
various temperatures and in various crosslinker contents. Composite rate constants, kr were determined
and gelation activation energies, ΔEG were measured.
Facultative H2‐dependent anoxygenic photosynthesis in the unicellular cyanobacteriumGloeocapsa alpicola CALU 743
Authors: Serebryakova Larissa , Novichkova Natalia , Gogotov Ivan
Published: March 2007

When cells of the unicellular cyanobacterium Gloeocapsa alpicola CALU 743 are deprived of
nitrate, the phycobilisomes are actively degraded by a proteolytic process termed chlorosis, which accompanied
by decrease of rates of oxygen evolution and carbon dioxide fixation, increase of amount of stored glycogen
and increase of hydrogenase activity. Suspensions of such cells exhibited a capacity for light‐dependent
inorganic carbon photoassimilation under anaerobic conditions in the presence of hydrogen and DCMU. The
rate of 14C incorporation was commensurable with that for nitrate‐sufficient cells at oxygenic photosynthesis
and reached 35–38 μmol 14Ch-1mg-1 Chl a. Incubation of G. alpicola grown aerobically in the presence of
limiting concentrations of nitrate under anaerobic conditions (Ar, CO2, DCMU) in the light with addition of
nitrate and H2, resulted in the increase of cellular protein, evidencing that G. alpicola cells with high level of
hydrogenase activity are able to perform H2‐dependent anoxygenic photosynthesis at levels supporting the
growth of this cyanobacterium.
Photocatalytic degradation of chlorinated ethenes
Authors: Oki Kyoichi , Tsuchida Sachiko , Nishikiori Hiromasa , Tanaka Nobuaki , Fujii Tsuneo
Published: March 2007

Degradation of three chlorinated ethenes, trichloroethylene, trans‐1,2‐dichloroethylene and cis‐1,2‐dichloroethylene, by UV‐light irradiated TiO2 catalyst prepared by the sol‐gel method in dry air at ambient
temperature have been examined by using FTIR measurement. The chlorinated ethenes rapidly decomposed
to produce dichloroacethyl chloride, CO, HCl, and COCL2. For trans‐ and cis‐1,2‐DCE systems isomerization
to each other is found to be the first step of the degradation. The C = C bond of the chlorinated ethenes
interacts directly with TiO2 site and, consequently, the degradation results in several products on the catalyst
surface in these systems.
Photocatalytic decomposition of gaseous formaldehyde using TiO2, SiO2‐TiO2 and Pt‐TiO2
Authors: Lee Byung-Yong , Kim Sung-Wook , Lee Sung-Chul , Lee Hyun-Ho , Choung Suk-Jin
Published: March 2007

In this study, in order to improve the photocatalytic decomposition activities of formaldehyde,
TiO2 catalyst modified with SiO2 substitution and metal (Pt, Cu and Fe) impregnation, were tested. In case of
TiO2 substituted by SiO2, the optimal catalytic activity was found at the mole ration of 2: 8. Among the metal
impregnated TiO2, the Pt impregnated TiO2 showed the best activity even better than that of P‐25 which is
widely used in commercial application. However, Cu and Fe impregnated TiO2 showed the reverse effect. In the case of SiO2 substituted TiO2 the observed values of photoluminescence spectroscopy were quite
proportional to the photocatalytic activities depending upon the mole ratio of SiO2 to TiO2. However, for the samples of metal impregnated TiO2, the reverse relationships were found. In UV‐visible spectra for metal
impregated TiO2, the transmittance value was reduced depending upon the loading of metals. The enhanced
photocatalytic activity for high metal loading on TiO2 might be associated with the high concentration of
excited electron that was monitored through UV‐visible spectra.
Fate of nitrogen atoms in the photocatalytic degradation of industrial (congo red) and alimentary (amaranth) azo dyes. Evidence for mineralization into gaseous dinitrogen
Authors: Puzenat E. , Lachheb H. , Karkmaz M. , Houas A. , Guillard C. , Herrmann J. M.
Published: March 2007

The photocatalytic degradation of two azo‐dyes–an industrial one (Congo Red (CR)), and an
alimentary one (Amaranth (AM))–has been investigated in TiO2/UV aqueous suspensions. In addition to a
prompt removal of the colors, TiO2/UV‐based photocatalysis was simultaneously able to fully oxidize the
dyes, with a complete mineralization of organic carbon into CO2. In particular, the aromatic rings were submitted
to successive attacks by photogenerated OH∘ radicals leading to hydroxylated metabolites before the
ring opening and the final evolution of CO2 induced by repeated subsequent “photo‐Kolbe” reactions with
carboxylic intermediates. Simultaneously, sulfur heteroatoms were converted into innocuous SO42− ions. The mineralization of nitrogen was more complex to analyze. Nitrogen atoms in the ‐3 oxidation state, such
as in the amino‐groups of CR, initially remained at this reduction degree and produced NH4+ cations, subsequently and very slowly converted into NO3− anions. For both azo‐dyes (CR and AM) degradation, the overall
mass balance in nitrogen was always found incomplete. Various experiments performed in pure oxygen in
a vacuum‐tight cell and then in an air‐free photoreactor (but filled with pure oxygen) enabled us to put in
evidence the formation of N2. Quantitative measurements clearly indicated that gaseous dinitrogen evolved
stoichiometrically corresponded to the mineralization of the central –N=N– azo‐group. This constitutes the
ideal issue for the elimination of nitrogen‐containing pollutants, not only for environmental photocatalysis
but also for any other physicochemical method. These results suggest that TiO2/UV photocatalysis may be
envisaged as a method for treatment of diluted colored waste waters not only for decolorization but also for
total detoxification, in particular in textile industries in semi‐arid countries.
Mechanistic and kinetic study of solar‐light induced photocatalytic degradation of Acid Orange 7 in aqueous TiO2 suspensions
Authors: Stylidi Maria , Kondarides Dimitris I. , Verykios Xenophon E.
Published: March 2007

The photocatalytic degradation of aqueous solutions of Acid Orange 7 in TiO2 suspensions has been investigated with the use of a solar light simulating source. It has been found that, when the full
range of emitted photons is used, decolorization and complete mineralization of the solution is achieved
with satisfactory rates, depending on initial dye concentration. A reaction pathway is proposed according
to which degradation of the dye molecules adsorbed on the photocatalyst surface takes place via a series of
oxidation steps, which lead to decolorization and formation of a number of intermediates, mainly aromatic
and aliphatic acids, which are further oxidized toward compounds of progressively lower molecular weight.
Eventually, mineralization is achieved leading to the formation of gas phase CO2 and inorganic ions in solution.
Kinetic results show that the initial rate of decolorization depends strongly on surface coverage and on
incident photon energy. Visible light photons contribute to decolorization, via the photosensitization mechanism,
but with reaction rates which are more than two orders of magnitude lower than the corresponding
ones induced by photons of energy higher than that of the band gap of the semiconductor. In both cases,
the initial rate of decolorization is significantly reduced for dye coverages close to monolayer.
Effect of partial oxidation by ozonation on the photocatalytic degradation of humic acids
Authors: Kerc Aslihan , Bekbolet Miray , Saatci Ahmet Mete
Published: March 2007

In this study humic acids, which are known to be a heterogeneous group of organic macromolecules
found in natural waters, were oxidized using ozonation and photocatalysis in a sequential system.
Ozonation was employed for achieving partial oxidation of humic acids prior to photocatalytic oxidation.
Degradation of humic acid was explained by using pseudo first order reaction rate model based on UV‐vis
measurements. An improvement was achieved in the photocatalytic degradation rates with respect to the
degree of pre‐oxidation by ozonation. Due to the surface oriented nature of photocatalysis, adsorption characteristics
of partially oxidized humic acid samples on TiO2 photocatalyst were evaluated by the application
of the Freundlich adsorption model. The photocatalytic degradation rates did not correlate well with the
dark adsorption characteristics of the pre‐ozonated as well as untreated humic acid samples.
Photocatalytic decomposition of fatty stains by TiO2 thin films
Authors: Vicente Juan Peris , Gacoin Thierry , Barboux Philippe , Boilot Jean-Pierre , Rondet Mauricette , Guéneau Léthicia
Published: March 2007

Anatase TiO2 nanoparticles have been prepared as aqueous colloidal solutions by a conventional
sol‐gel process. Thin films have been deposited onto glass substrates by dip‐coating and eventually further
crystallized by heat‐treatment up to 300∘C. The effect of the TiO2 film thickness, porosity and particle
size on the reaction kinetics has been studied as well as the starting thickness of the fatty acid layer. The
photocatalytic activity of the films has been measured through the decomposition of artificial stains formed
by fatty acids deposited onto the TiO2 layer (adipic or stearic acid). The kinetics of stain photodecomposition
has been studied in details by in-situ infrared spectroscopy absorption studies. This allows to discuss the role
of UV light absorption and the interdiffusion of radicals and oxygen across the interfaces. The mechanism
for stain decomposition is shown to be associated to a shrinkage of the solid film at the surface of the porous
oxide film after a diffusion of the excited radicals from the oxide.
Enhanced activity of silver modified thin‐film TiO2 photocatalysts
Authors: Falaras P. , Arabatzis I. M. , Stergiopoulos T. , Bernard M. C.
Published: March 2007

Novel, composite silver/titania immobilized on glass substrates were prepared, characterized
and their photocatalytic activity was evaluated. The undoped original material consists of rough, high surface
area nanocrystalline titanium dioxide (TiO2) thin films. To increase their efficiency, the TiO2 films were
modified by silver cations deposition and subsequent UV‐C irradiation. SEM pictures confirmed the existence
of an open porous network of interconnected titania particles on the semiconductor surface. AFM
analysis proved the presence of spherical silver particles on the catalyst surface and provided quantitative
surface parameters as fractal dimension, surface roughness and mean particle diameter. Spectroreflectometry
showed the presence of an increase in optical absorbance attributed to plasmon resonance absorption of
the silver clusters. The photocatalytic properties of the surface modified materials were investigated through
photodegradation of Methyl Orange. The silver deposition conditions were optimized for maximum photocatalytic
efficiency and crucial parameters such as dipping period, UV irradiation time, and concentration
of the dipping solution were determined. The optimum silver nitrate concentration of the dipping solution
was found to be 10-3 M. This silver doped photocatalyst decomposes the azo‐dye pollutant 3‐times faster
than the un‐doped Degussa P25 TiO2 film. A concentration increase results in a decrease of the films photocatalytic
performance. Strength and reproducibility tests proved that the photocatalytic activity of the silver
doped titania was perfectly reproducible.
Co‐treatment of industrial air streams using A.O.P. and adsorption processes
Authors: Monneyron P. , De La Guardia A. , Manero M. H. , Oliveros E. , Maurette M. T. , Benoit-Marquié F.
Published: March 2007

Coupling adsorption with two different photochemical oxidation methods was investigated, in
order to treat industrial gaseous effluents containing a low concentration of Volatile Organic Compounds
(VOC). Prior to adsorption/photocatalysis cyclic study, new TiO2 based catalysts were prepared by impregnating
commercial zeolites in pellets form using a sol‐gel technique. Scanning Electronic Microscopy observations
linked to BET and adsorption equilibrium measurements of two VOC (1‐butanol or BuOH and
methyl‐ethyl‐ketone or MEK) showed that TiO2 happened to fix on the inert binder, without significant modification
of support properties. A specific diffusion cell was used to produce dilute polluted air streams for
each VOC in dynamic experiments, in which adsorption and photodegradation phases were alternatively
carried out. Adsorption/photocatalysis co‐treatment unable the total degradation of BuOH, and the regeneration
of adsorbent. When using V‐UV photolysis, pure zeolites were used, irradiated at 172 nm with an
xenon excimer lamp. Excellent results were observed, since a total and rapid degradation was obtained for
both VOC, especially thanks to a determining role of ozone.
Semiconductors as sensitisers for the radical addition of tertiary amines to electron deficient alkenes
Authors: Marinković Siniša , Hoffmann Norbert
Published: March 2007

Using heterogeneous photocatalysis, the radical addition of tertiary amines with electron deficient
alkenes can be performed in high yields (up to 98%) and high facial diastereoselectivity. The photochemical
induced electron transfer process initiates the radical chain reaction and inorganic semiconductors
like TiO2 and ZnS were used. According to the proposed mechanism, the reaction takes place at the surface
of the semiconductor and the termination step results from an interfacial electron transfer from the conduction
band to the oxoallyl radical intermediate. Frequently, semiconductors are used for the mineralisation
of organic compounds in wastewater. However, in this case, they are used in organic synthesis. The process
can be performed in a convenient way and is particularly interesting from the ecological and economical
point of view. No previous functionalization of the tertiary amines is necessary for C ‐ C bond formation.
Further on, the amines are used both as reactant and as solvent. The excess is recycled by distillation and the
inexpensive sensitiser can be easily removed by filtration. In this way, products of high interest for organic
synthesis are obtained by a diastereoselective radical reaction.
Core/shell nanomaterials in photovoltaics
Authors: Arici Elif , Meissner Dieter , Schäffler F. , Sariciftci N. Serdar
Published: March 2007

Hybrid materials consist of inorganic nanoparticles embedded in polymer matrices. An advantage
of these materials is to combine the unique properties of one or more kinds of inorganic nanoparticles
with the film forming properties of polymers. Most of the polymers can be processed from solution at room
temperature enabling the manufacturing of large area, flexible and light weight devices. To exploit the full
potential for the technological applications of the nanocrystalline materials, it is very important to endow
them with good processing attributes. The surface of the inorganic cluster can be modified during the synthesis
by organic surfactants. The surfactant can alter the dispersion characteristic of the particles by initiating
attractive forces with the polymer chains, in which the particles should be homogenously arranged. In this
review, we present wet chemical methods for the synthesis of nanoparticles, which have been used as photovoltaic
materials in polymer blends. The photovoltaic performance of various inorganic/organic hybrid solar
cells, prepared via spin‐coating will be the focus of this contribution.
Photosensitized degradation of dinitrosalicylic acid by uranyl ions
Authors: Essawy A. A. I. , Abdel-Mottaleb M. S. A.
Published: March 2007

The photodegradation of dinitrosalicylic acid (DNS) by photoexcited uranyl ion was studied
in aqueous solutions. The failure of DNS to degrade directly with light highlights the importance of the
photoexcited uranyl ion in controlling the photochemical processes. Fluorescence quenching studies showed
that an electron‐transfer process from the DNS to the excited uranyl ion is involved leading to the formation
of UO2 +/DNS•+ radical pair complex as an initial step. Illumination of the UO2 2+/DNS solution in presence
of oxygen results in mineralization of DNS. The results are explained on the basis of a catalytic cycle involving UO2 2+ ion and molecular oxygen that generates reactive superoxide O2 •− anion and its conjugate acid HO2 •. The efficiency of the photocatalytic cycle is enhanced markedly by addition of dilute NaOH solution.
Quantum yields of photocoloration and molar absorption coefficients of ferrocenyl substituted benzo and dibenzochromenes. Comparisonwith their phenyl‐homologues
Authors: Brun Pierre , Guglielmetti Robert , Micheau Jean Claude , Pimienta Véronique , Anguille Stéphane
Published: March 2007

The photochromic properties of three ferrocenyl‐[2H]‐benzopyrans were investigated under
monochromatic irradiation and compared with those of their phenyl homologues. The UV/visible spectra of
the closed and open forms are reported together with the quantum yields of photocoloration. It was shown
that the ferrocenyl‐ substitution induces the formation of a new band in the 500–700 nm range in the open
forms, however, it does not affect significantly the UV spectra of the closed forms. Ferrocenyl‐ substitution
was also shown to increase the thermal bleaching rate constants and to decrease the photocoloration quantum
yields. For most compounds, photochromic behaviour was not sensitive to the irradiation wavelength.
However, for the methyl ferrocenyl chromene, the open form spectrum was slightly dependent of the irradiation
wavelength. The influence of the ferrocenyl group and other structural features on the photochromic
properties are discussed.
Towards molecular photochemionics
Authors: Venturi Margherita , Balzani Vincenzo , Ballardini Roberto , Credi Alberto , Gandolfi M. Teresa
Published: March 2007

In the last few years there has been a great interest in developing electronics at a molecular level
(molecular electronics), e.g. to construct miniaturized electric circuits that would be much smaller than the
corresponding micron‐scale digital logic circuits fabricated on conventional solid‐state semiconductor chips.
An alternative possibility to the use of electron fluxes as a means for information processing (electronics) is
that of using optical beams (photonics), but up until now scarce attention has been devoted to the possibility
of developing photonics at the molecular level. In this paper we review some recent achievements in the
design and construction of molecular‐level systems that are capable of transferring, switching, collecting,
storing, and elaborating light signals. The combination of molecular photonics with chemionics can lead to
a wealth of molecular‐level devices capable of information processing.
Electron transfer processes of coadsorbed Anthracene and N,N‐Dimethylaniline on titania‐silica
Authors: Eremenko Anna , Smirnova Natalie , Yakimenko Oksana , Starukh Galina , Worrall David R. , Williams Siân L.
Published: March 2007

The effect of titania‐silica binaries on the processes of PET and the decay kinetics of the
Anthracene (An) fluorescence and An radical cation in presence of the co‐adsorbed electron donor N,Ndimethylaniline
(DMA) has been studied. The fluorescence of excited An adsorbed on pure silica is quenched
by the addition of DMA, while co‐adsorption of DMA on Ti/Si binaries resulted in increase of fluorescence
intensity of adsorbed An. We suggest that competitive adsorption between DMA and An results in DMA
occupying more active “titania” sites causing the shift of An molecules to weaker adsorption sites located
on the silica support. An and DMA molecules being adsorbed simultaneously on the surface, effectively produce
reduced titanium ions due to an electron transfer process. These data appear to lend weight to the
suggestion of a pre‐exciplex An‐DMA state on the surface and effective PET from the excited molecular pair
to the acceptor sites on the surface. These sites may be titania aggregates, or titania ions when there is a low
content of Ti in the binaries.
Solvent free interactions in contact pairs of molecules of biological interest: Laser spectroscopic andelectrospray mass spectrometric studies
Authors: Scuderi D. , Paladini A. , Satta M. , Catone D. , Rondino F. , Filippi A. , Piccirillo S. , Speranza M. , Guidoni A. Giardini
Published: March 2007

A laser spectroscopic and mass spectrometric study of ionic and molecular clusters of biological
interest is reported. The molecules of interest and their aggregates were generated in a supersonic beam and
analyzed by mass resolved resonant two photon absorption and ionization (R2PI) and by collision induced
mass spectrometry (CID‐MS). The absence of the solvent allows to study these systems in the isolated state
free of undesired solvent effects which may level off the differences in their properties. The gas phase results
have been compared to theoretical estimates of the structure and stability of the systems under investigation.
Synthesis and photophysics of 6‐dimethylaminopurine‐capped Q‐CdS nanoparticles—a study of its photocatalytic behavior
Authors: Kumar Anil , Mital Shipra
Published: March 2007

Nanoparticles of CdS have been stabilized in aqueous medium by surface capping with 6‐
dimethylaminopurine at pH 11.0 in the presence of excess Cd2+. The nucleation of the cluster is controlled
through coordination of 6‐dimethylaminopurine via. ‐ group. Excess 6‐dimethylaminopurine binds
to the core structure through H‐bonding involving protonated N(9). CdS capped with 6‐dimethylaminopurine
produced relatively small sized particles (2 nm) having a narrow size distribution. These particles did not
exhibit any Ostwald′s ripening and its solid sample could be fully redispersed in aqueous medium. Thermolysis
results in the growth of these particles but demonstrates a better photocatalytic activity. Relaxation
kinetics reveals the surface to contain a large number of surface states and the emission is originated by the
presence of sulfur vacancies on the particle. The addition of indole simply quenches the emission of CdS in
a bimolecular collisional process at a diffusion‐controlled rate of about 9 × 109dm3mol−1s−1. Irradiation of the reaction mixture containing CdS and indole by light of λ > 360 nm results in the formation of indigo
with a quantum efficiency of 0.1.
Photodegradation of organic pollutants in aqueous solutions caused by Fe(OH)aq2+ photolysis: Evidence of OH radical formation
Authors: Pozdnyakov I. P. , Sosedova Yu. A. , Plyusnin V. F. , Glebov E. M. , Grivin V. P. , Vorobyev D. Yu. , Bazhin N. M.
Published: March 2007

Photochemistry of Fe(III) hydroxocomplexes has a great interest because of possibility of hydroxyl radical formation at the primary photochemical step. This mechanism is based mainly on the analysis
of the final products of photochemical reactions between light‐excited Fe(III) complexes and organic compounds. However, realization of an alternative mechanism of photolysis, based on the intermolecular electron
transfer from organic molecules located in the second coordination sphere to the light‐excited complex could take place. To distinguish these mechanisms, the experiments on the nanosecond laser flash photolysis of
Fe(OH)aq2+ in water solutions (pH 3) with organic additives; namely nitrobenzene, N,N‐dimethylformamide, and phenol have been performed. And the formation of the organic radicals Ph(•OH)NO2, HCON(CH2•)(CH3), and Ph(OH)2•, was observed, respectively. The rate constants of the formation and decay of the radicals coincide with those found in literature. The results support the formation of the hydroxyl radical upon the
photolysis of Fe(OH)aq2+.
Effect of morphology on electron drift mobility in porous TiO2
Authors: Aduda B. O. , Ravirajan P. , Choy K. L. , Nelson J.
Published: March 2007

Porous titanium dioxide is an attractive material for solar cell application on account of its
stability, electron transport properties, and the possibilities for controlling surface morphology as well as
for its ease of fabrication and low cost. Nanostructured TiO2 has been intensively studied for applications
to dye sensitised solar cells. The performance of the titanium dioxide based solar cells is influenced, among
other factors, by the electron mobility of the porous titanium dioxide. Different fabrication processes for
porous titanium films result in different film morphology, which in turn affects the electron transport. We
have employed three different techniques namely, electrostatic spray assisted vapour deposition (ESAVD),
D.C. reactive sputtering, and doctor blading of sol‐gel dispersions to deposit thin TiO2 films onto indium tin
oxide (ITO) coated glass substrates. All these films exhibited only the anatase phase as confirmed by X‐ray
diffraction analysis. Using the time‐of‐flight technique, the electron drift mobility in the porous TiO2 films was measured. The results show that in the low field region (< 55,000 V cm−1) the mobility, in all the films, were in the range of 10−7 to 10−6cm 2Vs−1. The drift mobility in the films prepared by reactive sputtering
was consistently higher than in the films prepared by the two other techniques. Sputter deposited films had
lower porosity (∼ 10% and 36% for normal‐, and oblique (60∘)‐angle deposited films) compared to ∼ 50% for films deposited by the two other techniques. The relationship between the drift mobility and film morphology
is discussed with the aid of scanning electron microscopy studies.
Contribution of NMR spectroscopy to the mechanistic understanding of photochromism
Authors: Delbaere S. , Micheau J. C. , Berthet J. , Vermeersch G.
Published: March 2007

Along with classical UV‐Visible spectroscopy allowing for the determination of intrinsic properties
(λmax, ε), multinuclear NMR spectroscopy is a promising and useful tool for studying photochromic
reactions. UV irradiation of the initial structure leads to the formation of photoproducts, which can be structurally
identified by 1D and 2D NMR experiments. The kinetics of thermal back reaction are monitored by
directly and separately measuring the concentrations of each long‐living species at regular time intervals
in NMR spectra. A plausible reaction mechanism can therefore be proposed. Based on this mechanism, the
kinetic analysis and the study of the effects of temperature lead to the determination of the kinetic and
thermodynamic parameters (rate coefficients, enthalpy and entropy of activation) of the photochromic system
under investigation. This process has been applied to several photochromic families, spirooxazines and
benzo‐ and naphtho‐pyrans.
5‐Ureido‐3,3‐diphenyl‐3H‐naphtho[2,1‐b]pyrans: Photoswitchable self‐assembling architectures
Authors: Sallenave X. , Delbaere S. , Ahmed S. , Vermeersch G. , Pozzo J. L.
Published: March 2007

5‐Ureido‐3,3‐diphenyl‐3H‐naphtho[2,1‐b]pyrans have been synthesized and their photochromic
properties have been quantified using UV‐Visible spectroscopy. The urea pattern is responsive for the selfassembling
properties under both colourless and coloured forms whereas the corresponding amino derivatives
do not show any aggregative properties. The geometries of the different states have been assigned using 1H and 19F NMR spectroscopies, and thereafter their respective kind of aggregates could be proposed through
the different inter‐ and intramolecular interactions. Upon UV irradiation, the pyranic ring is opened and the
resulting photogenerated carbonyl group is competing with the urea in the self‐assembling process and consequently
strongly affects the supramolecular assemblies. The inter‐ and intramolecular contributions have
been quantified through 1D and 2D NMR experiments along with the variation in the concentration.
A comparative study of the photochemistry of biphenyl adsorbed on cellulose and silicalite
Authors: Da Silva J. P. , Ferreira L. F. Vieira
Published: March 2007

The photochemistry of biphenyl (BP) was studied on two model solid supports, silicalite and
cellulose, using time resolved diffuse reflectance techniques and product degradation analysis. The results
showed that the photochemical behaviour of BP depends on the solid support. Ground state absorption spectra
indicated a near planar configuration in the ground state. BP triplet state was the only species detected
on cellulose, while the radical cation (BP•+) was observed in silicalite. BP is relatively stable in both supports.
Prolonged irradiations in cellulose lead to the formation of the three monohydroxybiphenyls, while in
silicalite photooxidation products prevailed.
C‐N vs. C‐C Bond Photodissociation in N‐(tert‐butyldiphenylmethyl)aniline
Authors: Garas Stylianos , Siskos Michael G. , Zarkadis Antonios K.
Published: March 2007

The direct photolysis of the title aniline compound Ph2(Me3C) C‐NHPh in acetonitrile with 248 nm laser light results in the dissociation of the C‐N bond giving the corresponding (tert‐Bu)diphenylmethyl radical 1a• and the anilino radical PhNH• detectable by ns‐laser flash photolysis (LFP) and ESR spectroscopy.
The same radical 1a• is also produced from the corresponding (tert‐Bu)diphenylmethyl chloride
Ph2(Me3C)C‐Cl either photolytically in MeCN through C‐Cl bond homolysis or pulse radiolytically in THF;
the (tert‐Bu)diphenylmethyl cation is also detected, however, at sorter time scales because of its high reactivity
in the solvent MeCN. At higher laser pulse intensities the radical 1a• is reexcited by a second photon
leading through electrocyclization to the 4a,4b‐dihydro‐9‐tert‐butylfluorenyl radical (DHBF•) and finally to fluorenyl products. Product analyses of steady state photolyses using GC and GC‐MS gave as principal products
(tert‐Bu)diphenylmethane, aniline and various 9‐substituted fluorenyl derivatives, corroborating further
the primary C‐N bond cleavage and the formation of the radicals 1a• and PhNH•. Other conceivable dissociation
pathways leading to the C‐CMe3 or N‐H bond rupture were not observed.
Protonation effect on the excited state behaviour of some aza‐analogues of EE‐distyrylbenzene
Authors: Ginocchietti Gabriella , Mazzucato Ugo , Spalletti Anna
Published: March 2007

The photobehaviour of four aza‐analogues of EE‐distyrylbenzene bearing the heteroatom in
the two side rings [1,4‐di‐(2‐pyridylethenyl)benzene] or in the central ring [2,5‐di‐(phenylethenyl)pyridine,
2,6‐di(phenylethenyl)pyridine and the corresponding diene, 2,6‐di(phenylbutadienyl)pyridine] has been investigated
in aqueous solutions at pH 2 and 9, where the molecules are in mono‐protonated and neutral
forms, respectively. The type of conjugation, linear for the first two compounds and crossed for the others,
is particularly important in determining the spectral and photochemical properties. The main effects of the
protic solvent are a reduction of the radiative deactivation, prevalent in the corresponding hydrocarbons, and
an increase of the reactive deactivation, very modest in the hydrocarbons. The increase in photoreactivity to
detriment of fluorescence, observed in protic medium with respect to non‐polar solvents, is drastically emphasized
in acid medium where the fluorescence quantum yield decreases by an order of magnitude leading
to high values of the EE → ZE photoisomerization quantum yield. The presence of conformational isomerism
(two main conformers were detected) has been observed in both basic and acid media for compounds with
crossed conjugation and for the linearly conjugated 2,5 substituted pyridine. The results obtained give a
picture of the different photobehaviour of the neutral and protonated species and indicate the experimental
conditions to favour a specific relaxation pathway.
Why inorganic salts decrease the TiO2 photocatalytic efficiency
Authors: Guillard Chantal , Puzenat Eric , Lachheb Hinda , Houas Ammar , Herrmann Jean-Marie
Published: March 2007

Methylene Blue (MB) has been chosen as a model molecule to evaluate the impact of inorganic
salts, present in textile waste waters, on the adsorption properties and on the photocatalytic efficiency of
TiO2. No OH∘ radical scavenging by anions such as NO3 −, Cl −, SO42−, PO43−, and CO32− was observed at neutral and basic pH, while this phenomenon can be suggested at acidic pH for some anions except carbonate
anions which are totally neutralized and/or eliminated as CO2   in these conditions. The decrease in the rate
MB photocatalytic degradation in the presence of inorganic salts was shown to be due to the formation of
an inorganic salt layer at the surface of TiO2, which inhibits the approach of MB molecules. The correlation
between the amount of MB adsorbed and the rate of its photocatalytic degradation, whatever the nature of
the salt, its concentration and the pH of the solution, indicates (i) that photocatalysis occurs at the surface
and not in the solution and (ii) that OH − ions added at basic pH do not participate to the increase in the
photocatalytic efficiency by inducing an increase in OH∘ formation. They increase the surface density in
adsorption sites TiO −. The effect of various salts is similar on various titania samples of industrial origin
(Millennium TiO2 PC 500, PC 50, and Degussa P 25). It is however more important on Millennium PC 10
probably because of its smaller surface area.
Photocatalytic degradation of reactive dye RED‐3BA in aqueous TiO2 suspension under UV‐visible light
Authors: Dung Nguyen Thi , Van Khoa Nguyen , Herrmann Jean-Marie
Published: March 2007

The photo‐catalytic degradation efficiency of several commercial titania powders (Degussa P‐25
and Ishihara Sangyo ST‐01) and of TiO2 supported on diatomite were investigated in the degradation of a
reactive dye (RED‐3BA) under UV‐Visible light. The observed rate constant for Degussa P‐25 was found to
be higher than that achieved by using Ishihara Sangyo ST‐01 (kobs = 3.3 × 10−2min−1 for Degussa P‐25 and 4 × 10−4min−1 for Ishihara Sangyo ST‐01). This could be related to the amount of basic hydroxyl groups
on the surface of TiO2 particles as shown in the IR spectra. TiO2 Degussa P‐25 supported on diatomite was
prepared by dip‐coating method. The photo‐catalytic activity of supported TiO2 was twice smaller than TiO2 Degussa P‐25 (kp-25 = 3.3 × 10−2min−1;kp25/diatomite = 1.6 × 10−2min−1). The higher surface areas of ST‐01 and the TiO2/diatomite could not lead to a higher degradation rate and to a higher degree of mineralization
but TiO2/diatomite could be separated more promptly and more easily from the solution. The effect of pH
was investigated in the range 4–9. Acidic (pH = 4) medium was found to favor the adsorption and degradation
rate with P‐25 particles.
Spin‐dependent diastereoselectivity in the photocycloaddition of aldehydes to 2,2‐dimethyl‐2,3‐dihydrofuran
Authors: Bondock Samir , Griesbeck Axel G.
Published: March 2007

The simple (non‐induced) diastereoselectivity of the photocycloaddition of aliphatic as well
as aromatic aldehydes to 2,2‐dimethyl‐2,3‐dihydrofuran (1) was analyzed as a function of the substrate
concentration (spin mapping) and rationalized in terms of optimal spin‐orbit coupling controlled triplet
biradical geometries.
Factors affecting light energy transfer in some samarium complexes
Authors: Bakier Esam , Abdel-Mottaleb M. S. A.
Published: March 2007

The photophysical properties of samarium ion in presence of 7‐Acetoxy Coumarin 3‐Carboxylic
acid (ACC) or 1‐(4‐methoxyphenyl) 3‐(4‐t‐butyl phenyl) 1,3‐propandione (MBPK), which act as antenna of
near‐UV radiation, are studied in different homogeneous, and heterogeneous media as well as in rigid polymethylmethacrylate
matrix (PMMA). High quantum yield value of the sensitized emission of (Sm3+ ‐(ACC)) and (Sm3+ ‐(MBPK)) in N,N‐dimethylformamide and PMMA matrix are obtained pointing to an efficient ligandto‐
metal energy transfer. Moreover, luminescence mappings for pattern recognition analysis that could be
profitably exploited as a useful identification method in clinical chemistry and biochemistry have been obtained
from which the nature of the solvent and/or the ligand is clearly identified by inspection of the
corresponding excitation/emission matrix maps.
Sunlight initiated atmospheric photochemical reactions
Authors: Vaida V.
Published: March 2007

The Sun is the light source driving atmospheric chemistry. The wavelengths dependent photon
flux is controlled by solar emission modulated by absorption of atmospheric gases, aerosols and clouds. The
factors determining the characteristics of this light source, its altitude, latitude and zenith angle dependence
are discussed to explain the effectiveness of the Sun in driving chemical reactions. Examples of chemical
reactions occurring on the excited and the ground electronic state potential energy surfaces of molecules and
radicals are used to illustrate the complexity of atmospheric photochemistry. Specifically, the near ultraviolet
(UV) photochemistry of chlorine dioxide is used to exemplify electronic state reactions occurring in the
atmosphere. The near infrared (IR) photochemistry of nitric and sulfuric acids are discussed to illustrate
reactions important in the atmosphere which occur with solar pumping of vibrational overtone transitions
in the ground electronic state of these molecules.
Degradation of octylbenzene sulfonate photoinduced by iron(III) aquacomplexes: Evidence for the fragmentation of the alkyl chain
Authors: Debbache Nadra , Mailhot Gilles , Djebbar Kamel , Lavedrine Bernadette , Bolte Michèle
Published: March 2007

The degradation of octylbenzene sulfonate (OBS) photoinduced by iron(III) aquacomplexes was
investigated upon irradiation at 365 nm and by solar light. The photochemical degradation appears to be due to
HO• radicals arising from the electron transfer in Fe(OH)2+. If oxygen does not affect the initial quantum yield of OBS degradation, it is necessary to pursue the reaction up to, first the complete disappearance of OBS and secondly OBS mineralization. The nature of the major photoproducts gives evidence for a competitive
attack of HO• radicals on the alkyl chain resulting in a shortening of the chain. Among the possible sites
on the chain, hydrogen on the carbon in α position with respect to the aromatic ring was the main point of
attack with the formation of 4‐acetylbenzene sulfonate and 4‐carboxylicbenzene sulfonate.