Andre Persoons - Academia.edu (original) (raw)
Papers by Andre Persoons
Organometallics, Jun 1, 1997
ABSTRACT
Journal of Organometallic Chemistry, Sep 1, 2000
The preparation of the chloro complex trans-[FeCl2{(R,R)-diph}2] (1) and the alkynyl complexes tr... more The preparation of the chloro complex trans-[FeCl2{(R,R)-diph}2] (1) and the alkynyl complexes trans-[M(4-CCC6H4R)Cl{(R,R)-diph}2] [M=Fe, R=NO2 (2); M=Ru, R=H (4), NO2 (5), (E)-CHCH-4-C6H4NO2 (6); M=Os, R=NO2 (7)], incorporating the optically active diphosphine 1,2-bis(methylphenylphosphino)benzene (diph), are described. Oxidation potentials, as determined by cyclic voltammetry, increase as 2&lt;7&lt;5. Molecular quadratic nonlinearities by hyper-Rayleigh scattering at 1064 nm increase upon introduction of an acceptor group (4&lt;5), chain-lengthening of bridging group (5&lt;6), and proceeding from 3d to 4d and 5d metal (2≤5≤7). Two-level-corrected nonlinearities reproduce the first two trends, but metal variation follows the sequence 2&lt;7&lt;5. The experimental and two-level-corrected nonlinearities for 6 (2795×10−30 and 406×10−30 esu, respectively), are amongst the largest observed thus far for organometallic complexes. Crystals of complexes 2 and 7 exhibit second-harmonic generation (assessed using the Kurtz powder technique), with an efficiency for the former of twice that of urea.
Journal of the American Chemical Society, Jan 27, 1999
Optics Letters, Oct 15, 2020
Miniaturized magnetic field sensors are increasingly used in various applications, such as geophy... more Miniaturized magnetic field sensors are increasingly used in various applications, such as geophysical exploration for minerals and oil, volcanology, earthquake studies, and biomedical imaging. Existing magnetometers lack either the spatial or the temporal resolution or are restricted to costly shielded labs and cannot operate in an unshielded environment. Increasing spatio-temporal resolution would allow for real-time measurements of magnetic fluctuations with high resolution. Here we report on a new nanocomposite-based system for miniaturized magnetic field sensing. The sensor is based on Dy 3-doped magnetite and cobalt ferrite nanoparticles dispersed in a polymer matrix. Operation is feasible at room temperature and in an unshielded environment. A compact fiber-optic interferometer is used as the detection mechanism with 20 fT∕ p Hz sensitivity. We investigated the magnetic field response of the sensor and demonstrated the measurement of the human heartbeat as a potential application.
Optics letters, 2018
Miniaturized magnetic field sensors are increasingly used in various applications, such as geophy... more Miniaturized magnetic field sensors are increasingly used in various applications, such as geophysical exploration for minerals and oil, volcanology, earthquake studies, and biomedical imaging. Existing magnetometers lack either the spatial or the temporal resolution or are restricted to costly shielded labs and cannot operate in an unshielded environment. Increasing spatio-temporal resolution would allow for real-time measurements of magnetic fluctuations with high resolution. Here we report on a new nanocomposite-based system for miniaturized magnetic field sensing. The sensor is based on Dy-doped magnetite and cobalt ferrite nanoparticles dispersed in a polymer matrix. Operation is feasible at room temperature and in an unshielded environment. A compact fiber-optic interferometer is used as the detection mechanism with 20 fT/√Hz sensitivity. We investigated the magnetic field response of the sensor and demonstrated the measurement of the human heartbeat as a potential application.
ECS Meeting Abstracts, 2010
not Available.
Journal of Organometallic Chemistry, Jul 1, 1998
The complexes trans-[Ru(2-CCC5H3N-5-R)Cl(dppm)2] [R=H (6), NO2 (7)] have been prepared and 7 has... more The complexes trans-[Ru(2-CCC5H3N-5-R)Cl(dppm)2] [R=H (6), NO2 (7)] have been prepared and 7 has been structurally characterized; comparison with the structural study of trans-[Ru(4-CCC6H4NO2)Cl(dppm)2] (3) reveals a decrease in Ru–C(1) distance and increase in Ru–Cl(1) distance, consistent with stronger σ-bonding by the nitropyridylalkynyl ligand in 7 compared to the nitrophenylalkynyl ligand in 3. Electrochemical data for 3, 6, 7, precursor dichloro
Inorganica Chimica Acta, Mar 1, 2005
The complexes [Ru{(Z)-HCCHPh}(CO)2(η5-C5Ph5)] (1) and [Ru{(Z)-HCCHC6H4NO2}(CO)2(η5-C5Ph5)] (2) ha... more The complexes [Ru{(Z)-HCCHPh}(CO)2(η5-C5Ph5)] (1) and [Ru{(Z)-HCCHC6H4NO2}(CO)2(η5-C5Ph5)] (2) have been synthesized and their identity confirmed by single-crystal X-ray diffraction studies. Reaction of 2 with PMe2Ph and Me3NO in tetrahydrofuran afforded [Ru{(Z)-HCCHC6H4NO2}(CO)(PMe2Ph)(η5-C5Ph5)] (3). Cyclic voltammetry confirms the expected increase in ease of oxidation on proceeding from 2 to 1 and from 2 to 3. Hyper-Rayleigh scattering studies at 1064 nm reveal a
Clays and Clay Minerals, 1997
Langmuir, Jan 17, 2001
Fuzzy assembled multicompound films consisting of natural and synthetic colloidal clay particles,... more Fuzzy assembled multicompound films consisting of natural and synthetic colloidal clay particles, poly-(diallyldimethylammonium chloride) (PDDA) and the dyes methylene blue (MB +) and 4-{4-[N-allyl-Nmethylamino]phenylazo}benzenesulfonic acid, sodium salt (NAMO-) have been prepared. The organization of the clay particles was imaged by means of atomic force microscopy. Fuzzy assembled glass/clay/methylene blue films have been investigated by visible spectroscopy, and the spectra were explained in terms of the substrate-clay interaction and clay particle overlap. Glass/clay/PDDA/NAMO films were investigated by means of absorption spectroscopy, polarized absorption spectroscopy, and second harmonic generation. The nonlinear optical properties of the films were found to be determined by the adsorbed amount of NAMO and its noncentrosymmetric organization. These factors are in turn governed by the substrate type, the PDDA concentration, and the clay type. Optimized second harmonic generation for the glass/laponite/ PDDA/NAMO films was found in which the clay particles are deposited onto a (3-aminopropyl)trimethoxysilane modified glass surface and PDDA chains are adsorbed from a 0.1 M solution.
Proceedings of SPIE, Nov 13, 2000
ABSTRACT We have studied the photorefractive properties of (2,4,7-trinitro-9- fluorenylidene)malo... more ABSTRACT We have studied the photorefractive properties of (2,4,7-trinitro-9- fluorenylidene)malononitrile (TNFM) sensitized poly(N-vinylcarbazole)/N- ethylcarbazole polymer composites doped with 2-(3,4,4-trimethylhex-2- ene-1-ylidene)-1,3-propanedinitrile and related dyes. Characterization included four-wave mixing experiments, two beam coupling and photoconductivity measurement at a wavelength of 780 nm. At an applied field of 53 V/micrometers , we have observed complete internal diffraction and at 60 V/micrometers a gain coefficient of 230 cm-1. Small alterations in the chromophore donor group substituents were used to tune the ionization potential of the dopant dye by 0.3 eV. They affected the grating build-up time, photorefractive phase shift, and complexation with TNFM. This performance is compared to that of three newly synthesized polymethacrylates functionalized with carbazole, a dodecyl chain as an internal plasticizer and three different dyes. Here we observe net two-beam coupling gain and a diffraction efficiency of 60% at 58 V/micrometers .
Inorganica Chimica Acta, Feb 1, 2006
The complexes trans-[Ru(CC-4-C6H4F)X(dppe)2] [X=Cl (1), CCPh (2), CC-4-C6H4NO2 (3)], trans-[Ru{CC... more The complexes trans-[Ru(CC-4-C6H4F)X(dppe)2] [X=Cl (1), CCPh (2), CC-4-C6H4NO2 (3)], trans-[Ru{CC-4-C6H4-(E)-CHCH-4-C6H4NO2}X(dppe)2] [X=CCPh (4), CC-4-C6H4CCPh (5)], and [C6H3-1,3-{CC-trans-[RuCl(dppe)2]}2-5-(CC-4-C6H4F)] (6) have been synthesized and the identity of 1 confirmed by a single-crystal X-ray diffraction study. Cyclic voltammetry reveals a metal-centered oxidation, the potential of which is largely invariant on alkynyl ligand replacement across the series 1–5; the diruthenium complex 6 shows two oxidation
Journal of Physical Chemistry C, Jul 5, 2017
The effects of stacking aromatic units on the Verdet constant are analyzed by employing quantum c... more The effects of stacking aromatic units on the Verdet constant are analyzed by employing quantum chemistry calculations and are compared to the effects of oligomerization. Building stacked oligomers leads to enhanced Verdet constants, but still smaller than in the corresponding linear oligomers. Further enhancements appear when going from simple to fused-ring polyaromatic compounds.
Macromolecules, Apr 25, 2000
forming an insoluble and intractable layer. No photoinitiator was used, hence minimizing continue... more forming an insoluble and intractable layer. No photoinitiator was used, hence minimizing continued photoreaction during the device lifetime. Aluminum electrodes are vapor-deposited under a vacuum of 10 ±6 mbar or better and silver paste dots applied for electrical contact. This entire fabrication process is carried out under dry nitrogen of purity greater than 99.99 %. Film thickness was measured using a Dektak 3 ST surface profiler. Samples are mounted for testing within a nitrogen-filled chamber with spring-loaded probes. The polyimide strips form a protective layer, preventing the spring-loaded test probes from pushing through the various layers. Optical absorbance measurements were taken using a Unicam UV-vis spectrometer with a polarizer (Ealing, Polarcoat 105 UV-vis code 23-2363) in the beam. The spectrometer's polarization bias was taken into account and dichroic ratios were obtained by comparing maxima at around 370±380 nm. Luminescence/voltage measurements were taken using a photomultiplier tube (EMI 6097B with S11-type photocathode) and Keithley 196 multimeter with computer control. Polarized EL measurements were taken using a photodiode array (Ocean Optics S2000, 200±850 nm bandwidth, 2 nm resolution) and polarizer as described above. The polarization bias of the spectrometer was eliminated by use of an input fiber (fused silica, 100 mm diameter), ensuring complete depolarization of light into the instrument.
Summary form only given. Recently, we studied horizontally dipped Langmuir-Blodgett (LB) films of... more Summary form only given. Recently, we studied horizontally dipped Langmuir-Blodgett (LB) films of a helicenebisquinone derivative. The molecules are organized into fibrous structures that are further organized into small domains (typically 50×100 nm). As a result the LB-films are anisotropic with a C2-symmetry and a high nonlinear optical (NLO) response. Gidalevitz et al. (1998) recently demonstrated that melting can increase the order in anisotropic LB-films. Since, order is a very desirable feature in nonlinear optics, we studied the effect of heating on the NLO-efficiency of a LB film of the helicenebisquinone derivative. In addition, we studied the influence of the dipping technique. We used the horizontal and vertical dipping technique to construct 30-layer thick LB-films of a helicenebisquinone derivative
Organometallics, Jun 1, 1997
ABSTRACT
Journal of Organometallic Chemistry, Sep 1, 2000
The preparation of the chloro complex trans-[FeCl2{(R,R)-diph}2] (1) and the alkynyl complexes tr... more The preparation of the chloro complex trans-[FeCl2{(R,R)-diph}2] (1) and the alkynyl complexes trans-[M(4-CCC6H4R)Cl{(R,R)-diph}2] [M=Fe, R=NO2 (2); M=Ru, R=H (4), NO2 (5), (E)-CHCH-4-C6H4NO2 (6); M=Os, R=NO2 (7)], incorporating the optically active diphosphine 1,2-bis(methylphenylphosphino)benzene (diph), are described. Oxidation potentials, as determined by cyclic voltammetry, increase as 2&lt;7&lt;5. Molecular quadratic nonlinearities by hyper-Rayleigh scattering at 1064 nm increase upon introduction of an acceptor group (4&lt;5), chain-lengthening of bridging group (5&lt;6), and proceeding from 3d to 4d and 5d metal (2≤5≤7). Two-level-corrected nonlinearities reproduce the first two trends, but metal variation follows the sequence 2&lt;7&lt;5. The experimental and two-level-corrected nonlinearities for 6 (2795×10−30 and 406×10−30 esu, respectively), are amongst the largest observed thus far for organometallic complexes. Crystals of complexes 2 and 7 exhibit second-harmonic generation (assessed using the Kurtz powder technique), with an efficiency for the former of twice that of urea.
Journal of the American Chemical Society, Jan 27, 1999
Optics Letters, Oct 15, 2020
Miniaturized magnetic field sensors are increasingly used in various applications, such as geophy... more Miniaturized magnetic field sensors are increasingly used in various applications, such as geophysical exploration for minerals and oil, volcanology, earthquake studies, and biomedical imaging. Existing magnetometers lack either the spatial or the temporal resolution or are restricted to costly shielded labs and cannot operate in an unshielded environment. Increasing spatio-temporal resolution would allow for real-time measurements of magnetic fluctuations with high resolution. Here we report on a new nanocomposite-based system for miniaturized magnetic field sensing. The sensor is based on Dy 3-doped magnetite and cobalt ferrite nanoparticles dispersed in a polymer matrix. Operation is feasible at room temperature and in an unshielded environment. A compact fiber-optic interferometer is used as the detection mechanism with 20 fT∕ p Hz sensitivity. We investigated the magnetic field response of the sensor and demonstrated the measurement of the human heartbeat as a potential application.
Optics letters, 2018
Miniaturized magnetic field sensors are increasingly used in various applications, such as geophy... more Miniaturized magnetic field sensors are increasingly used in various applications, such as geophysical exploration for minerals and oil, volcanology, earthquake studies, and biomedical imaging. Existing magnetometers lack either the spatial or the temporal resolution or are restricted to costly shielded labs and cannot operate in an unshielded environment. Increasing spatio-temporal resolution would allow for real-time measurements of magnetic fluctuations with high resolution. Here we report on a new nanocomposite-based system for miniaturized magnetic field sensing. The sensor is based on Dy-doped magnetite and cobalt ferrite nanoparticles dispersed in a polymer matrix. Operation is feasible at room temperature and in an unshielded environment. A compact fiber-optic interferometer is used as the detection mechanism with 20 fT/√Hz sensitivity. We investigated the magnetic field response of the sensor and demonstrated the measurement of the human heartbeat as a potential application.
ECS Meeting Abstracts, 2010
not Available.
Journal of Organometallic Chemistry, Jul 1, 1998
The complexes trans-[Ru(2-CCC5H3N-5-R)Cl(dppm)2] [R=H (6), NO2 (7)] have been prepared and 7 has... more The complexes trans-[Ru(2-CCC5H3N-5-R)Cl(dppm)2] [R=H (6), NO2 (7)] have been prepared and 7 has been structurally characterized; comparison with the structural study of trans-[Ru(4-CCC6H4NO2)Cl(dppm)2] (3) reveals a decrease in Ru–C(1) distance and increase in Ru–Cl(1) distance, consistent with stronger σ-bonding by the nitropyridylalkynyl ligand in 7 compared to the nitrophenylalkynyl ligand in 3. Electrochemical data for 3, 6, 7, precursor dichloro
Inorganica Chimica Acta, Mar 1, 2005
The complexes [Ru{(Z)-HCCHPh}(CO)2(η5-C5Ph5)] (1) and [Ru{(Z)-HCCHC6H4NO2}(CO)2(η5-C5Ph5)] (2) ha... more The complexes [Ru{(Z)-HCCHPh}(CO)2(η5-C5Ph5)] (1) and [Ru{(Z)-HCCHC6H4NO2}(CO)2(η5-C5Ph5)] (2) have been synthesized and their identity confirmed by single-crystal X-ray diffraction studies. Reaction of 2 with PMe2Ph and Me3NO in tetrahydrofuran afforded [Ru{(Z)-HCCHC6H4NO2}(CO)(PMe2Ph)(η5-C5Ph5)] (3). Cyclic voltammetry confirms the expected increase in ease of oxidation on proceeding from 2 to 1 and from 2 to 3. Hyper-Rayleigh scattering studies at 1064 nm reveal a
Clays and Clay Minerals, 1997
Langmuir, Jan 17, 2001
Fuzzy assembled multicompound films consisting of natural and synthetic colloidal clay particles,... more Fuzzy assembled multicompound films consisting of natural and synthetic colloidal clay particles, poly-(diallyldimethylammonium chloride) (PDDA) and the dyes methylene blue (MB +) and 4-{4-[N-allyl-Nmethylamino]phenylazo}benzenesulfonic acid, sodium salt (NAMO-) have been prepared. The organization of the clay particles was imaged by means of atomic force microscopy. Fuzzy assembled glass/clay/methylene blue films have been investigated by visible spectroscopy, and the spectra were explained in terms of the substrate-clay interaction and clay particle overlap. Glass/clay/PDDA/NAMO films were investigated by means of absorption spectroscopy, polarized absorption spectroscopy, and second harmonic generation. The nonlinear optical properties of the films were found to be determined by the adsorbed amount of NAMO and its noncentrosymmetric organization. These factors are in turn governed by the substrate type, the PDDA concentration, and the clay type. Optimized second harmonic generation for the glass/laponite/ PDDA/NAMO films was found in which the clay particles are deposited onto a (3-aminopropyl)trimethoxysilane modified glass surface and PDDA chains are adsorbed from a 0.1 M solution.
Proceedings of SPIE, Nov 13, 2000
ABSTRACT We have studied the photorefractive properties of (2,4,7-trinitro-9- fluorenylidene)malo... more ABSTRACT We have studied the photorefractive properties of (2,4,7-trinitro-9- fluorenylidene)malononitrile (TNFM) sensitized poly(N-vinylcarbazole)/N- ethylcarbazole polymer composites doped with 2-(3,4,4-trimethylhex-2- ene-1-ylidene)-1,3-propanedinitrile and related dyes. Characterization included four-wave mixing experiments, two beam coupling and photoconductivity measurement at a wavelength of 780 nm. At an applied field of 53 V/micrometers , we have observed complete internal diffraction and at 60 V/micrometers a gain coefficient of 230 cm-1. Small alterations in the chromophore donor group substituents were used to tune the ionization potential of the dopant dye by 0.3 eV. They affected the grating build-up time, photorefractive phase shift, and complexation with TNFM. This performance is compared to that of three newly synthesized polymethacrylates functionalized with carbazole, a dodecyl chain as an internal plasticizer and three different dyes. Here we observe net two-beam coupling gain and a diffraction efficiency of 60% at 58 V/micrometers .
Inorganica Chimica Acta, Feb 1, 2006
The complexes trans-[Ru(CC-4-C6H4F)X(dppe)2] [X=Cl (1), CCPh (2), CC-4-C6H4NO2 (3)], trans-[Ru{CC... more The complexes trans-[Ru(CC-4-C6H4F)X(dppe)2] [X=Cl (1), CCPh (2), CC-4-C6H4NO2 (3)], trans-[Ru{CC-4-C6H4-(E)-CHCH-4-C6H4NO2}X(dppe)2] [X=CCPh (4), CC-4-C6H4CCPh (5)], and [C6H3-1,3-{CC-trans-[RuCl(dppe)2]}2-5-(CC-4-C6H4F)] (6) have been synthesized and the identity of 1 confirmed by a single-crystal X-ray diffraction study. Cyclic voltammetry reveals a metal-centered oxidation, the potential of which is largely invariant on alkynyl ligand replacement across the series 1–5; the diruthenium complex 6 shows two oxidation
Journal of Physical Chemistry C, Jul 5, 2017
The effects of stacking aromatic units on the Verdet constant are analyzed by employing quantum c... more The effects of stacking aromatic units on the Verdet constant are analyzed by employing quantum chemistry calculations and are compared to the effects of oligomerization. Building stacked oligomers leads to enhanced Verdet constants, but still smaller than in the corresponding linear oligomers. Further enhancements appear when going from simple to fused-ring polyaromatic compounds.
Macromolecules, Apr 25, 2000
forming an insoluble and intractable layer. No photoinitiator was used, hence minimizing continue... more forming an insoluble and intractable layer. No photoinitiator was used, hence minimizing continued photoreaction during the device lifetime. Aluminum electrodes are vapor-deposited under a vacuum of 10 ±6 mbar or better and silver paste dots applied for electrical contact. This entire fabrication process is carried out under dry nitrogen of purity greater than 99.99 %. Film thickness was measured using a Dektak 3 ST surface profiler. Samples are mounted for testing within a nitrogen-filled chamber with spring-loaded probes. The polyimide strips form a protective layer, preventing the spring-loaded test probes from pushing through the various layers. Optical absorbance measurements were taken using a Unicam UV-vis spectrometer with a polarizer (Ealing, Polarcoat 105 UV-vis code 23-2363) in the beam. The spectrometer's polarization bias was taken into account and dichroic ratios were obtained by comparing maxima at around 370±380 nm. Luminescence/voltage measurements were taken using a photomultiplier tube (EMI 6097B with S11-type photocathode) and Keithley 196 multimeter with computer control. Polarized EL measurements were taken using a photodiode array (Ocean Optics S2000, 200±850 nm bandwidth, 2 nm resolution) and polarizer as described above. The polarization bias of the spectrometer was eliminated by use of an input fiber (fused silica, 100 mm diameter), ensuring complete depolarization of light into the instrument.
Summary form only given. Recently, we studied horizontally dipped Langmuir-Blodgett (LB) films of... more Summary form only given. Recently, we studied horizontally dipped Langmuir-Blodgett (LB) films of a helicenebisquinone derivative. The molecules are organized into fibrous structures that are further organized into small domains (typically 50×100 nm). As a result the LB-films are anisotropic with a C2-symmetry and a high nonlinear optical (NLO) response. Gidalevitz et al. (1998) recently demonstrated that melting can increase the order in anisotropic LB-films. Since, order is a very desirable feature in nonlinear optics, we studied the effect of heating on the NLO-efficiency of a LB film of the helicenebisquinone derivative. In addition, we studied the influence of the dipping technique. We used the horizontal and vertical dipping technique to construct 30-layer thick LB-films of a helicenebisquinone derivative