References of "Dreesen, Laurent"
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See detailAdsorption Properties of the Penicillin Derivative DTPA on Gold Substrates
Dreesen, Laurent ULg; Silien, Christophe; Volcke, Cédric et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2007), 8(7), 1071-1076

Despite the large number of articles and patents dealing with penicillin and other b-lactam antibiotics, there have been no reports about the self-assembly of such substances as monolayers on gold ... [more ▼]

Despite the large number of articles and patents dealing with penicillin and other b-lactam antibiotics, there have been no reports about the self-assembly of such substances as monolayers on gold surfaces. The main reason stems from the high reactivity of the b-lactam ring, which hinders the development of molecules possessing this entity together with a metal-anchoring function. Herein, we present the synthesis of a novel molecule, 6-[(R,S)-5-(1,2-dithiolan-3-yl)pentanoyl-amino]-penicillanic acid, which combines the b-lactam ring and a metal-anchoring group. Using spectroscopic tools, we demonstrate the chemisorption of this compound on gold as self-assembled monolayers without any alteration of the penicillin pharmacophore and document its reactivity towards a penicillin-binding protein, BlaR-CTD. Our work is a preliminary step towards the development of new biosensors and well-ordered protein arrays, both based on the high affinity of penicillin for penicillin-binding proteins. [less ▲]

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See detailHigh energy and short pulses generation by Nd:yttrium aluminum garnet laser mode-locked using frequency-doubling nonlinear mirror
Mani, A. A.; Lis, D.; Grawet, L. et al

in Optics Communications (2007), 276

The generation of laser pulses with energies of >40 mJ at 25 Hz and durations variable from 15 ps to 45 ps using an Nd:yttrium aluminum garnet laser mode-locked with a Stankov nonlinear mirror is ... [more ▼]

The generation of laser pulses with energies of >40 mJ at 25 Hz and durations variable from 15 ps to 45 ps using an Nd:yttrium aluminum garnet laser mode-locked with a Stankov nonlinear mirror is demonstrated. This laser is used to pump an optical parametric generator-amplifier, which is tunable in the visible spectral range. [less ▲]

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See detailSynthesis and characterization of aromatic self-assembled monolayers containing methylene and ethyleneglycol entities by means of sum-frequency generation spectroscopy
Dreesen, Laurent ULg; Sartenaer, Y.; Peremans, A. et al

in Thin Solid Films (2006), 500

We use infrared-visible sum-frequency generation (SFG) spectroscopy in order to investigate the adsorption properties on Pt(111) of molecules having CH3–C6H4–(O–CH2–CH2)n –O–(CH2)m –SH as general chemical ... [more ▼]

We use infrared-visible sum-frequency generation (SFG) spectroscopy in order to investigate the adsorption properties on Pt(111) of molecules having CH3–C6H4–(O–CH2–CH2)n –O–(CH2)m –SH as general chemical formula. We synthesized three molecules defined by the values m=5 n =4, m =11 n =4, m=11 n =8 and characterized them by Nuclear Magnetic Resonance spectroscopy. Thanks to spectroscopic measurements, we show that these molecules build self-assembled monolayers on Pt(111). First, the weak SFG signals arising from the ad-layer indicate low order and surface coverage of the substrate by these molecules. Next, the vibrational fingerprints of the aforementioned molecules are determined between 2825 and 3125 cm 1 and the observed SFG spectral features are ascribed on the basis of the analysis of shorter and simpler molecules (1- dodecanethiol, 4-methylbenzenethiol and CH3–C6H4–O–(CH2)11–SH) also adsorbed on Pt(111). The occurrence of methylene vibration modes indicates a significant amount of chain defects whatever the n and m numbers are. Finally, the identification of a particular vibration mode, characteristic of the aromatic ring, enables us to qualitatively discuss the effect of the number of methylene and ethylene glycol entities on its orientation. More precisely, higher these numbers, more tilted (with respect to the substrate normal) the aromatic ring plane is. [less ▲]

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See detailComparative study of decyl thiocyanate and decanethiol self-assembled monolayers on gold substrates
Dreesen, Laurent ULg; Volcke, C.; Sartenaer, Y. et al

in Surface Science (2006), 600

In a recent paper Ciszek et al. [J.W. Ciszek, M.P. Stewart, J.M. Tour, J. Am. Chem. Soc. 126 2004) 13172] showed that organic thiocyanates may be an interesting alternative to the use of thiols for ... [more ▼]

In a recent paper Ciszek et al. [J.W. Ciszek, M.P. Stewart, J.M. Tour, J. Am. Chem. Soc. 126 2004) 13172] showed that organic thiocyanates may be an interesting alternative to the use of thiols for thiolate assemblies. We use scanning tunnelling microscopy (STM), infrared reflection absorption and sum-frequency generation spectroscopies (IRRAS and SFG) in order to study the adsorption properties of decyl thiocyanates (DTCN) and compare them to the decanethiol (DT) ones. Firstly, IRRAS measurements show that DTCN molecules form self-assembled monolayers (SAMs) on gold via a thiolate link with the metallic substrate. Secondly, the DTCN SAM on gold is less ordered than the DT one as highlighted by SFG spectroscopy. Indeed, the intensities of the methyl vibration modes vanish while the methylene ones increase when DTCN molecules are adsorbed on the substrate instead of DT. We explain the differences in SAMs quality on the basis of STM measurements which reveal differences in molecular order and packing. [less ▲]

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See detailMolecular conformation and electronic properties of protoporphyrin-IX self-assembled monolayers adsorbed on a Pt(111) surface
Humbert, C.; Volcke, C.; Sartenaer, Y. et al

in Surface Science (2006), 600

Monolayers of protoporphyrin-IX molecules are prepared on a Pt(111) surface by a self-assembly process in order to manufacture organic devices with controlled electronic properties. Scanning tunnelling ... [more ▼]

Monolayers of protoporphyrin-IX molecules are prepared on a Pt(111) surface by a self-assembly process in order to manufacture organic devices with controlled electronic properties. Scanning tunnelling microscopy (STM) and two-colour sum-frequency generation (2C-SFG) are performed ex situ in ambient air, in order to characterize their molecular conformation and electronic properties at the monolayer level, respectively. STM measurements performed with functionalized gold tips reveal a high covering rate of the metal surface. 2C-SFG measurements highlight CH stretching modes of vinyl substituted groups (R-CH=CH2) in the 2800–3200 cm-1 infrared spectral range and particular electronic features in the visible spectral range, i.e. a Soret band red shift and band separation compared to the liquid phase. Moreover, similar measurements are performed on Zn(II)Protoporphyrin-IX and 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin films for comparison. These results suggest a film conformation with the molecules having different tilt angles with respect to the substrate normal, depending on the ion metal presence or the chain length bonded to the porphyrin moiety. [less ▲]

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See detailOn the Protoporphyrin Monolayers Conformation
Humbert, Christophe; Dreesen, Laurent ULg; Sartenaer, Yannick et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2006), 7

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See detailThiocyanate and thiol self-assembling process on platinum investigated by means of sum-frequency generation
Sartenaer, Yannick; Tourillon, Gérard; Louette, Pierre et al

Poster (2005, September)

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See detailComparative study of decyl thiocyanate and decanethiol self-assembled monolayers on gold substrates
Dreesen, Laurent ULg; Volcke, Cédric; Sartenaer, Yannick et al

Poster (2005, September)

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See detailMolecular conformation and electronic properties of protoporphyrin-IX self-assembled monolayers adsorbed on Pt(111) surface
Humbert, Christophe; Volcke, Cédric; Sartenaer, Yannick et al

Poster (2005, September)

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See detailSum-frequency generation from surface species in porous silicon
Mattei, Giorgio; Valentini, Veronica; Yakovlev, Vladimir et al

in Phys. Stat. Sol. (a) (2005), 202(8), 1487-1491

For the first time, the sum-frequency generation (SFG) spectra of surface species have been measured in porous silicon (PS) layers. The range of the vibrations 2000–2300 cm–1 for the native species Si–Hx ... [more ▼]

For the first time, the sum-frequency generation (SFG) spectra of surface species have been measured in porous silicon (PS) layers. The range of the vibrations 2000–2300 cm–1 for the native species Si–Hx has been explored. Furthermore for the studied mesoporous materials, it has been found that, as opposed to the infrared absorption, the SFG signal increases with porosity. Finally, the angular dependence and the enhancement of the SFG signal were measured in a one-dimensional PS photonic crystal structure with a defect producing an energy level in the photonic band gap. [less ▲]

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See detailSum-frequency generation spectrocopy applied to model biosensors systems
Dreesen, Laurent ULg; Sartenaer, Yannick; Humbert, Christophe et al

Conference (2004, November)

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See detailTwo-color-sum-frequency generation characterization of a protein monolayer adsorbed on a metallic substrate
Dreesen, Laurent ULg; Sartenaer, Yannick; Humbert, Christophe et al

Poster (2004, June)

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See detailTwo-color-sum-frequency generation characterization of a protein monolayer adsorbed on a metallic substrate
Dreesen, Laurent ULg; Sartenaer, Yannick; Humbert, Christophe et al

Poster (2004, May 25)

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See detailPicosecond laser for performance of efficient nonlinear spectroscopy from 10 to 21 mm
Mani, A. A.; Schultz, Z. D.; Gewirth, A. A. et al

in Optics Letters (2004), 29(3), 274-276

Laser tunability from 10 to 21 mm is obtained by use of an optical parametric oscillator based on a KTP crystal followed by a difference-frequency stage with a CdSe crystal. An all-solid-state picosecond ... [more ▼]

Laser tunability from 10 to 21 mm is obtained by use of an optical parametric oscillator based on a KTP crystal followed by a difference-frequency stage with a CdSe crystal. An all-solid-state picosecond Nd:YAG oscillator mode locked by a frequency-doubling nonlinear mirror is used for synchronous pumping. [less ▲]

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See detailMethanol dissociative adsorption on Pt(1 0 0) as studied by nonlinear vibrational spectroscopy
Vidal, Franck; Busson, B.; Six, C. et al

in Journal of Electroanalytical Chemistry (2004), 563

The methanol dissociative adsorption on Pt(1 0 0) at low potentials in the hydrogen region is studied using nonlinear vibrational sum-frequency generation (SFG) spectroscopy. It is shown that adsorbed ... [more ▼]

The methanol dissociative adsorption on Pt(1 0 0) at low potentials in the hydrogen region is studied using nonlinear vibrational sum-frequency generation (SFG) spectroscopy. It is shown that adsorbed hydrogen atoms effectively block atop sites at the surface. In the hydrogen potential region, CO produced by the methanol dissociation adsorbs at step-edges and in bridge sites on terraces as shown by the characteristic stretching frequencies observed for adsorbed CO. [less ▲]

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See detailPotential-dependent structure of the interfacial water on the gold electrode
Nihonyanagi, Satoshi; Ye, Shen; Uosaki, Kohei et al

in Surface Science (2004), 573

Doubly tunable sum frequency generation (SFG) spectra demonstrate that the water molecules at gold/electrolyte interface change their orientation with applied potential. At negative potentials, water ... [more ▼]

Doubly tunable sum frequency generation (SFG) spectra demonstrate that the water molecules at gold/electrolyte interface change their orientation with applied potential. At negative potentials, water molecules in the double layer align with their oxygen atom pointing to the solution. As potential became positive to be close to the potential of zero charge (PZC), the SFG signal decreased, suggesting the OH groups of the water molecule are either in random orientation or parallel to the electrode. As potential became more positive than the PZC, the SFG signal increased again with the oxygen-up orientation as same as in the negative potential region, indicating that water molecules interact with the adsorbed sulfate anions. The peak position of the SFG spectra indicates a relatively disordered state of water molecules at the gold electrode surface, in contrast to the previously observed ice-like structure of water at electrolyte/oxide interfaces. [less ▲]

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See detailProbing Ligand–Protein Recognition with Sum-Frequency Generation Spectroscopy: The Avidin–Biocytin Case
Dreesen, Laurent ULg; Sartenaer, Yannick; Humbert, Christophe et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2004), 5

Infrared/visible sum-frequency generation (SFG) spectroscopy is used to study the recognition of a protein (avidin) by a derived vitamin (biocytin) adsorbed on a calcium fluoride substrate. The ... [more ▼]

Infrared/visible sum-frequency generation (SFG) spectroscopy is used to study the recognition of a protein (avidin) by a derived vitamin (biocytin) adsorbed on a calcium fluoride substrate. The specificity of the process is tested by replacing avidin with bovine serum albumin or presaturated avidin. The SFG spectroscopy shows drastic modifications in the CH and NH spectral ranges only upon exposure of the biocytin film to avidin. The comparison of the SFG data with Fourier transform infrared reflection absorption spectra (FT-IRRAS) in the same spectral ranges illustrates the advantages of nonlinear spectroscopy for studying and detecting recognition between biomolecules. [less ▲]

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See detailElectronic and Molecular Properties of an Adsorbed Protein Monolayer Probed by Two-Color Sum-Frequency Generation Spectroscopy
Dreesen, Laurent ULg; Humbert, C.; Sartenaer, Y. et al

in Langmuir (2004), 20(17), 7201-7207

Two-color sum-frequency generation spectroscopy (2C-SFG) is used to probe the molecular and electronic properties of an adsorbed layer of the green fluorescent protein mutant 2 (GFPmut2) on a platinum ... [more ▼]

Two-color sum-frequency generation spectroscopy (2C-SFG) is used to probe the molecular and electronic properties of an adsorbed layer of the green fluorescent protein mutant 2 (GFPmut2) on a platinum (111) substrate. First, the spectroscopic measurements, performed under different polarization combinations, and atomic force microscopy (AFM) show that the GFPmut2 proteins form a fairly ordered monolayer on the platinum surface. Next, the nonlinear spectroscopic data provide evidence of particular coupling phenomena between the GFPmut2 vibrational and electronic properties. This is revealed by the occurrence of two doubly resonant sum-frequency generation processes for molecules having both their Raman and infrared transition moments in a direction perpendicular to the sample plane. Finally, our 2C-SFG analysis reveals two electronic transitions corresponding to the absorption and fluorescence energy levels which are related to two different GFPmut2 conformations: the B (anionic) and I forms, respectively. Their observation and wavelength positions attest the keeping of the GFPmut2 electronic properties upon adsorption on the metallic surface. [less ▲]

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See detailOrientation of Thiophenol Adsorbed on Silver Determined by Nonlinear Vibrational Spectroscopy of the Carbon Skeleton
Mani, A. A.; Schultz, Z. D.; Caudano, Y. et al

in Journal of Physical Chemistry B (2004), 108

The orientation of thiophenol adsorbed on silver is determined by comparing ab initio calculated and experimental sum-frequency generation (SFG) spectra measured between 9 and 20 µm using a tandem KTP ... [more ▼]

The orientation of thiophenol adsorbed on silver is determined by comparing ab initio calculated and experimental sum-frequency generation (SFG) spectra measured between 9 and 20 µm using a tandem KTP/CdSe optical parametric oscillator. The molecule S-C bond is tilted ~37° from the surface normal with the aromatic ring plane perpendicular to the surface. [less ▲]

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