| 1. |
- Arora, Kapildev K., et al.
(author)
-
Supramolecular synthesis of some molecular adducts of 4,4′-bipyridine N,N′-dioxide
- 2009
-
In: New Journal of Chemistry. - 1144-0546 .- 1369-9261. ; 33:1, s. 57-63
-
Journal article (peer-reviewed)abstract
- Molecular adducts (1a–1e) of 4,4′-bipyridine N,N′-dioxide, 1, respectively with cyanuric acid, trithiocyanuric acid, 1,3,5-trihydroxybenzene (phloroglucinol), 1,3-dihydroxybenzene (resorcinol) and 1,2,4,5-benzenetetracarboxylic acid have been reported. The major interactions observed in the structures 1a–1e are N–H⋯O, N–H⋯S, O–H⋯O and C–H⋯O, in the form of homomeric and heteromeric patterns of the constituents, either as a single or cyclic hydrogen-bonded motifs. While in the adduct 1a, both homomeric and heteromeric units of both the constituents were observed, no heteromeric interactions were observed in 1b and 1c. In addition, in 1b, homomeric aggregation of molecules of 1 occurred in association with water molecules. However, while heteromeric interactions prevail between the constituents in 1d and 1e, only one of the co-crystallizing species gave homomeric interactions (4,4′-bipyridine N,N′-dioxide in 1d; 1,2,4,5-benzenetetracarboxylic acid in 1e). Further, in either type of the patterns, the cyclic motifs are formed as a pair-wise hydrogen bonds comprising of strong and weak hydrogen bonds (N–H⋯O/C–H⋯O or O–H⋯O/C–H⋯O). In three-dimensions, the ensembles of molecules yield planar sheets, ladders and pseudorotaxane type assemblies
|
|
| 2. |
- Bernhardt, Paul V., et al.
(author)
-
Tailoring mixed-valence Co-III/Fe-II complexes for their potential use as sensitizers in dye sensitized solar cells
- 2008
-
In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 32:4, s. 705-711
-
Journal article (peer-reviewed)abstract
- Dinuclear class II Co-III/Fe-II mixed-valence complexes of type [LnCo (III)(mu-NC) Fe-II(CN)(3)L-2](m-) (where L-n represents a pentadentate macrocycle and L-2 a bpy ligand or two cyanides) have electronic properties that make them possible sensitizers in DSSC ( dye sensitized solar cells). For this purpose the new complex Na-2[{trans-L14COOCo III( m-NC)} Fe II( CN) 5] has been prepared and characterized by the usual methods and its sensitizer properties compared with those of the already known [{trans-L14COOCo (III)(mu-NC)}Fe-II(CN)(5)](2-)(CN)(3)(bipy)(eq,ax)](ClO4). The complex [{trans-L14COOCo (III)(mu-NC)}Fe-II(CN)(5)](2-) has been designed for the actuation of an electron injection from the cobalt centre on MMCT, while the [{trans-L14COOCo (III)(mu-NC)}Fe-II(CN)(3)(bipy)](+) structure can produce a tuned injection from the iron centre via an MLCT electronic state, as described for similar systems. The characterization on solid oxide semiconductor supports has been carried out for these two complexes and the results have been compared with the behaviour observed in aqueous solution and in solvents of varying polarities. Their use in DSSC has been checked and, while a sensitizer response is observed for [{trans-L14COOCo (III)(mu-NC)}Fe-II(CN)(5)](2-), complex [{trans-L14COOCoIII(mu-NC)}Fe-II(CN)(3)(bipy)(eq,ax)](+) does not produce any electrical current on illumination. The low efficiency of the built DSSC can be easily related both with the very low value of the extinction coefficient of the MMCT band responsible for the electron injection, and with the small driving force for the reduction of the complex with the standard I-2/I-3 (-) system used after electron injection.
|
|
| 3. |
- Bouit, Pierre-Antoine, et al.
(author)
-
Dendron-decorated cyanine dyes for optical limiting applications in the range of telecommunication wavelengths
- 2009
-
In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33:5, s. 964-968
-
Journal article (peer-reviewed)abstract
- Cyanine dyes decorated with 2,2-bis(methylol) propionic acid (bis-MPA) based dendrons up to third generation were synthesized. Dendrons were attached to the chromophore using a "click chemistry'' reaction. Photophysical characterizations of these dyes show intense absorption and emission in the near-infrared (NIR), while nonlinear transmission experiments of the dendron-decorated chromophores indicate that properties in the IR of the parent dyes are conserved. This synthetic approach is a crucial preliminary step towards the preparation of solid functional materials for optical limiting (OL) applications in the IR.
|
|
| 4. |
- Chaignon, Frederique, et al.
(author)
-
Photoinduced electron transfer in ruthenium(II) trisbipyridine complexes connected to a naphthalenebisimide via an oligo(phenyleneethynylene) spacer
- 2009
-
In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33:2, s. 408-416
-
Journal article (peer-reviewed)abstract
- The preparation and the characterization of three new dyads composed of a ruthenium trisbipyridine complex linked to a naphthalene bisimide electron acceptor via a phenyleneethynylene spacer of different length (one or two units) are reported. The dyads also differ by the anchoring position of the spacer on the bipyridine, which is appended either at the 4-position or the 5-position. Cyclic voltammetry and the UV-Vis absorption spectroscopy suggested that the spacer linked at the 5-position ensures a longer pi-conjugation length but the electron transfer rates indicate a lower electronic coupling, than in 4-position. Photoinduced emission yields indicate a significant quenching of the MLCT excited-state of the ruthenium complex in these dyads. Except for the dyad linked in 5 position with one phenyleneethynylene unit, the transient absorption spectroscopy of all the other dyads evidences that the MLCT excited-state decays almost exclusively by electron transfer to form the charge-separated state Ru-III-NBI-. This state could not be observed, presumably because the subsequent recombination to the ground state was much faster than its formation. In the dyad linked in 5 position with only one phenyleneethynylene unit, at room temperature, the (MLCT)-M-3* state is in equilibrium with the (NBI)-N-3* state, and it also decays via electron transfer. The notable feature of these dyads is first the occurrence of a relatively long-range electron transfer reaction via a bis(phenylethynylene) linking unit anchored at the 5 position. Secondly, we show within these series of compounds that subtle variations in the structure of the dyads (length of the spacer and anchoring position on bipy) have a strong impact on the rates and in the mechanism of decay of the (MLCT)-M-3* state. The photophysical properties of the dyads can be explained in terms of energy proximity of different excited states and magnitude of the electronic coupling according to the anchoring position.
|
|
| 5. |
- Dinér, Peter, 1976, et al.
(author)
-
Short cut to 1,2,3-triazole-based p38 MAP kinase inhibitors via [3+2]-cycloaddition chemistry
- 2009
-
In: New J. Chem.. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33:5, s. 1010-1016
-
Journal article (peer-reviewed)abstract
- A series of 4,5-substituted 1,2,3-triazoles was synthesised via Cu(I)-catalysed azide–alkyne 1,3-dipolar [2+3]-cycloaddition reactions followed by a Suzuki coupling. The 1,2,3-triazoles were evaluated as inhibitors of the p38 MAP kinase, showing IC50 values in the high nanomolar range
|
|
| 6. |
|
|
| 7. |
- Ghazzali, Mohamed I D M, 1974, et al.
(author)
-
Syntheses, crystal structures, optical limiting properties, and DFT calculations of three thiophene-2-aldazine Schiff base derivatives
- 2007
-
In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 31:10, s. 1777-1784
-
Journal article (peer-reviewed)abstract
- The syntheses, characterizations and structural determinations of N,N'-bis(thiophenyl-2-methylene)hydrazine 1, N,N'-bis(4-bromothiophenyl-2-methylene)hydrazine 2 and N,N'-bis(5-bromothiophenyl-2-methylene)hydrazine 3 are presented. The materials show third-ordernonlinear behaviour with transmissions of 20, 22 and 18 μJ for an input energy of 150 μJ. The4- and 5-bromothiophenic structures show Br...Br interactions of 3.562 and 3.626 Å, respectively.Analysis of bromine containing aromatic compounds in the Cambridge CrystallographicDatabase (CSD) showed the expected angle dependences of the Br...Br interactions dividing theseinto ‘‘type I’’ and ‘‘type II’’. A semi-quantitative agreement was found between the CSD data anda model derived form calculated electrostatic potentials.
|
|
| 8. |
- Gromov, SP, et al.
(author)
-
Novel supramolecular charge-transfer systems based on bis(18-crown-6)stilbene and viologen analogues bearing two ammonioalkyl groups
- 2005
-
In: NEW JOURNAL OF CHEMISTRY. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 29:7, s. 881-94
-
Journal article (peer-reviewed)abstract
- A series of new viologen analogues bearing two ammonioalkyl groups (2-4) were synthesized in order to study their complexation with bis(18-crown-6)stilbene (1b). Electronic spectroscopy and H-1 NMR measurements show that in acetonitrile, bis( crown) stilbene 1b forms highly stable 1 : 1 and 2 : 1 charge-transfer (CT) complexes with pi-acceptors 2-4 owing to host-guest bonding. The influence of geometric and electronic factors on the complex formation constants are discussed. The structures of the supramolecular CT complexes are analyzed on the basis of H-1 and C-13 NMR data obtained in solution and in the solid state. X-Ray diffraction data for 1b and for model tetramethoxystilbene are also reported.
|
|
| 9. |
- Kenne, Lennart, et al.
(author)
-
The use of diffusion-ordered spectroscopy and complexation agents to analyze mixtures of catechins
- 2009
-
In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 33, s. 1057-1063
-
Journal article (peer-reviewed)abstract
- Mixtures of catechins, (+)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG) have been analyzed by diffusion-ordered spectroscopy (DOSY) using liquid and high-resolution magic angle spinning (HR-MAS) NMR probes. Beta-cyclodextrin (beta-CD) and bovin serum albumin (BSA), often used as ligands in affinity chromatography, were added to the mixture of catechins to mimic chromatographic conditions and modify the average mobility. The influence of the solvent, water, dimethyl sulfoxide, methanol, acetone and acetonitrile, was also investigated. The best separation of the components was achieved with beta-CD in the liquid probe using a 15% CD(3)CN-85% D(2)O solution, and this was applied to the analysis of catechins from green tea extract. The parts of the catechin molecules having the closest contact to the BSA protein were also determined by saturation transfer difference (STD) NMR experiments.
|
|
| 10. |
- Moores, Audrey, et al.
(author)
-
Catalysed low temperature H-2 release from nitrogen heterocycles
- 2006
-
In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 30:11, s. 1675-1678
-
Journal article (peer-reviewed)abstract
- In an experimental and computational study, nitrogen- and oxygen-containing heterocycles were compared with carbocycles as liquid substrates for hydrogen release with heterogeneous catalysts. Heteroatom substitution, particularly by nitrogen, favours low temperature H-2 release; indoline was fully dehydrogenated in less than 30 min with Pd/C at 110 degrees C.
|
|
| 11. |
- Paolesse, R., et al.
(author)
-
Insights on the chemistry of a,c-biladienes from a CSPT investigation
- 2008
-
In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 32:7, s. 1162-1166
-
Journal article (peer-reviewed)abstract
- Computer Screen Photoassisted Technique (CSPT) is a recent interesting approach for the development of optical sensor platforms using ubiquitous devices. We demonstrate here that the information obtained by CSPT measurements can be useful for other than sensing purposes and a computer set and a web camera can also be exploited as spectroscopic technique for the characterization of the compounds used as indicators. CSPT measurement data have been used to characterize novel features of the a,c-biladiene chemistry, which have been later confirmed by photophysical characterization carried out using classical instrumentation. The demonstrated analytical capabilities of a regular computer-web camera set reach a degree of complexity approaching that of fluorescence excitation-emission spectroscopy, something remarkable considering the exploitation of familiar and already well distributed devices. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
|
|
| 12. |
- Polavarapu, Prasad, et al.
(author)
-
Modulation and binding properties of extended glycoluril molecular clips
- 2008
-
In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 32:4, s. 643-651
-
Journal article (peer-reviewed)abstract
- A glycoluril clip (1) provides a deep cavity for binding of guest molecules. Guest species interactpreferentially via hydrogen bonding or ion–lone pair interactions. Complexation-inducedconformational modulation of the cavity wall distance was observed. At higher guest–host ratios,inclusion compounds with organic guest molecules are obtained. The X-ray crystallographicstructure of 1.(NH4PF6).3CHCl3.2CH3OH shows formation of a network of clips connected viapolar and non-polar interactions.
|
|
| 13. |
|
|
| 14. |
- Zhang, Xuanjun, et al.
(author)
-
From Large 3D Assembly to Highly Dispersed Spherical Assembly: Weak- and Strong- Coordination Mediated Self-Aggregation of Au Colloids
- 2006
-
In: New Journal of Chemistry. - : RSC Publishing. - 1144-0546 .- 1369-9261. ; 30, s. 706-711
-
Journal article (peer-reviewed)abstract
- Distinctly different 3D assemblies of 1.6 nm Au nanoparticles are constructed based on weak and strong coordination strategies. Reduction of KAuCl4 with NaBH4 in the presence of newly-synthesized 4-(4-phenylmethanethiol)-2,2′:6′,2′′-terpyridine (1) yields functionalized Au nanoparticles which assemble in situ into large 3D aggregates via weak coordination between alkali metal ions and terpyridine attached to separated particles. These assemblies are disassembled into individual nanoparticles via addition of DMF solvent and further reassembled into highly dispersed 3D spherical nanostructures via addition of Co2+ (strong coordination with 1). Wide and small angle XRD measurements show that the assemblies are formed from small Au nanoparticles, consistent with TEM results. It is significant that the large aggregates formed in situ can be directly transformed into nearly monodispersed 3D spherical assemblies via strong coordination (with Co2+), presenting the first example of a direct transformation of one 3D nanonetwork into another distinctly different 3D nanonetwork. The controlled assembly and disassembly processes are accompanied by distinct shifts in the surface plasmon resonance.
|
|
| 15. |
|
|
