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Molecules, Volume 8, Issue 1 (January 2003) – 22 articles , Pages 1-222

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265 KiB  
Article
Spectroscopic and Theoretical Studies of Quantum and Electronic Confinement Effects in Nanostructured Materials
by Lei Z. Zhang, Wei Sun and Peng Cheng
Molecules 2003, 8(1), 207-222; https://doi.org/10.3390/80100207 - 31 Jan 2003
Cited by 53 | Viewed by 12233
Abstract
Nanostructured materials have become the central subject of materials research during the last decade in the past 20th century owing to the novel electronic, optical, and catalytic properties observed in such materials. The unusual properties of these nanostructured materials can be attributed to [...] Read more.
Nanostructured materials have become the central subject of materials research during the last decade in the past 20th century owing to the novel electronic, optical, and catalytic properties observed in such materials. The unusual properties of these nanostructured materials can be attributed to two main microscopic effects: quantum confinement and electronic confinement. These two effects have dominated the variations of molecular properties in a wide variety of nanostructured materials, ranging from inorganic compounds to organic molecules. The recent advances have focused on host-guest complex systems that have resulted in a deeper understanding of the changes in electronic structures when being confined. In this article we cover some of the key advances in the study of quantum and electronic confinement effects, especially in host-guest systems. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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166 KiB  
Article
Molecular Dynamics Simulations of Nanochannel Flows at Low Reynolds Numbers
by Xiao-Bing Mi and Allen T. Chwang
Molecules 2003, 8(1), 193-206; https://doi.org/10.3390/80100193 - 31 Jan 2003
Cited by 34 | Viewed by 13018
Abstract
In this paper we use molecular dynamics (MD) simulations to study nanochannel flows at low Reynolds numbers and present some new interesting results. We investigated a simple fluid flowing through channels of different shapes at the nano level. The Weeks-Chandler-Anderson potentials with different [...] Read more.
In this paper we use molecular dynamics (MD) simulations to study nanochannel flows at low Reynolds numbers and present some new interesting results. We investigated a simple fluid flowing through channels of different shapes at the nano level. The Weeks-Chandler-Anderson potentials with different interaction strength factors are adopted for the interaction forces between fluid -fluid and fluid -wall molecules. In order to keep the temperature at the required level, a Gaussian thermostat is employed in our MD simulations. Comparing velocities and other flow parameters obtained from the MD simulations with those predicted by the classical Navier-Stokes equations at same Reynolds numbers, we find that both results agree with each other qualitatively in the central area of a nanochannel. However, large deviation usually exists in areas far from the core. For certain complex nanochannel flow geometry, the MD simulations reveal the generation and development of nano-size vortices due to the large momenta of molecules in the near-wall region while the traditional Navier-Stokes equations with the non-slip boundary condition at low Reynolds numbers cannot predict the similar phenomena. It is shown that although the Navier-Stokes equations are still partially valid, they fail to give whole details for nanochannel flows. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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194 KiB  
Article
Synthesis and Bioactivity of a-Aminophosphonates Containing Fluorine
by Bao-An Song, Yang-Lan Wu, Song Yang, De-Yu Hu, Xiang-Qiong He and Lin-Hong Jin
Molecules 2003, 8(1), 186-192; https://doi.org/10.3390/80100186 - 31 Jan 2003
Cited by 52 | Viewed by 9969
Abstract
Twenty-one a-aminophosphonates containing fluorine were synthesized by Mannich-type reactions. Their structures were established by elemental analysis, IR, 1H- NMR and MS. In field tests, some of these new compounds display high antiviral activity against the tobacco mosaic virus (TMV). The molecular geometry [...] Read more.
Twenty-one a-aminophosphonates containing fluorine were synthesized by Mannich-type reactions. Their structures were established by elemental analysis, IR, 1H- NMR and MS. In field tests, some of these new compounds display high antiviral activity against the tobacco mosaic virus (TMV). The molecular geometry of compound 4f was determined by X-ray diffraction structure analysis. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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87 KiB  
Article
Valence Topological Charge-Transfer Indices for Dipole Moments
by Francisco Torrens
Molecules 2003, 8(1), 169-185; https://doi.org/10.3390/80100169 - 31 Jan 2003
Cited by 18 | Viewed by 9996
Abstract
New valence topological charge-transfer indices are applied to the calculation of dipole moments. The algebraic and vector semisum charge-transfer indices are defined. The combination of the charge-transfer indices allows the estimation of the dipole moments. The model is generalized for molecules with heteroatoms. [...] Read more.
New valence topological charge-transfer indices are applied to the calculation of dipole moments. The algebraic and vector semisum charge-transfer indices are defined. The combination of the charge-transfer indices allows the estimation of the dipole moments. The model is generalized for molecules with heteroatoms. The ability of the indices for the description of the molecular charge distribution is established by comparing them with the dipole moments of a homologous series of phenyl alcohols. Linear and non-linear correlation models are obtained. The new charge-transfer indices improve the multivariable non-linear regression equations for the dipole moment. When comparing with previous results, the variance decreases 92%. No superposition of the corresponding Gk–Jk and GkV – JkV pairs is observed. This diminishes the risk of co-linearity. Inclusion of the oxygen atom in the p-electron system is beneficial for the description of the dipole moment, owing to either the role of the additional p orbitals provided by the heteroatom or the role of steric factors in the p-electron conjugation. Linear and non-linear correlations between the fractal dimension and various descriptors point not only to a homogeneous molecular structure but also to the ability to predict and tailor drug properties. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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551 KiB  
Article
Fabrication of Unimolecular Double-stranded DNA Microarrays on Solid Surfaces for Probing DNA-Protein/Drug Interactions
by Jinke Wang, Tongxiang Li, Yunfei Bai, Yi Zhu and Zuhong Lu
Molecules 2003, 8(1), 153-168; https://doi.org/10.3390/80100153 - 31 Jan 2003
Cited by 17 | Viewed by 10848
Abstract
We present a novel method for fabricating unimole cular double-stranded DNA microarrays on solid surfaces, which were used to probe sequence-specific DNA/protein interactions. For manufacturing the unimolecular double-stranded DNA microarrays, two kinds of special single-stranded oligonucleotides, constant oligonucleotide and target oligonucleotide, were chemically [...] Read more.
We present a novel method for fabricating unimole cular double-stranded DNA microarrays on solid surfaces, which were used to probe sequence-specific DNA/protein interactions. For manufacturing the unimolecular double-stranded DNA microarrays, two kinds of special single-stranded oligonucleotides, constant oligonucleotide and target oligonucleotide, were chemically synthesized. The constant oligonucleotides with internal aminated dT were used to capture and immobilize the target oligonucleotides onto the solid surface, and also to provide a primer for later enzymatic extension reactions, while target oligonucleotides took the role of harbouring DNA-binding sites of DNA-binding proteins. The variant target oligonucleotides were annealed and ligated with the constant oligonucleotides to form the new unimolecular oligonucleotides for microspotting. The prepared unimolecular oligonucleotides were microspotted on aldehyde-derivatized glass slides to make partial-dsDNA microarrays. Finally, the partial-dsDNA microarrays were converted into a unimolecular complete-dsDNA microarray by a DNA polymerase extension reaction. The efficiency and accuracy of the polymerase synthesis were demonstrated by the fluorescent-labeled dUTP incorporation in the enzymatic extension reaction and the restriction endonuclease digestion of the fabricated unimolecular complete-dsDNA microarray. The accessibility and specificity of the sequence-specific DNA-binding proteins binding to the immobilized unimolecular dsDNA probes were demonstrated by the binding of Cy3 labeled NF-?B (p50·p50) to the unimolecular dsDNA microarray. This unimolecular dsDNA microarray provides a general technique for high-throughput DNA-protein or DNA-drugs interactions. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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37 KiB  
Article
Hepatic Mitochondrial Redox Potential in Patients with Liver Metastatic Cancers and Circulatory Insufficiency
by Piotr Tomaszewski, Grazyna Kubiak-Tomaszewska, Jan Pachecka, Marcin Balcerzak, Bozena Haznar, Cezary Pszenny, Marek Krawczyk, Pawel Paczkowski and Marek Jarecki
Molecules 2003, 8(1), 146-152; https://doi.org/10.3390/80100146 - 31 Jan 2003
Viewed by 11100
Abstract
Arterial ketone body ratio (AKBR), which reflects hepatic intramitochodrial redox potential, was measured in 20 patients with Carcinoma hepatis metastaticum and good circulatory condition (group A), and 16 patients with Carcinoma hepatis metastaticum and chronic cardiogenic circulatory insufficiency (group B). Total ketone body [...] Read more.
Arterial ketone body ratio (AKBR), which reflects hepatic intramitochodrial redox potential, was measured in 20 patients with Carcinoma hepatis metastaticum and good circulatory condition (group A), and 16 patients with Carcinoma hepatis metastaticum and chronic cardiogenic circulatory insufficiency (group B). Total ketone body concentration (TKB) and arterial oxygen tension (PaO2) was simultaneously determined. We have stated that AKBR values in both groups of patients were decreased below the normal level. AKBR values in group B were significantly lower than in group A. At the same time TKB values in both groups were statistically equal and significantly increased above the normal level. The levels of arterial oxygen tension (PaO2) in group A were physiologically high, whereas in group B were significantly decreased. Furthermore arterial oxygen tension of patients in group B correlated with AKBR values significantly. In group A we found statistically significant negative correlation between TKB and AKBR values. Our study indicate that the main mechanism which may explain the decrease of intrahepatic mitochondrial redox potential in patients with liver metastatic cancers and good circulatory condition, is the enhanced beta-oxidation of fatty acids, when the efficiency of NAD+ to NADH reduction in beta-oxidation pathway and tricarboxylic acid cycle is higher than re-oxidation of NADH to NAD+ in the oxidative phosphorylation. In patients with coexisting chronic cardiogenic circulatory insufficiency deprivation of blood oxygen supply initiate the irreversible dysfunction of oxidative phosphorylation. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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65 KiB  
Article
Analysis of Rotational Transitions of Methyl Formate in the Ground and First Excited Torsional States
by Hitoshi Odashima, Kazumi Ogata, Kojiro Takagi and Shozo Tsunekawa
Molecules 2003, 8(1), 139-145; https://doi.org/10.3390/80100139 - 31 Jan 2003
Cited by 11 | Viewed by 7506
Abstract
The microwave spectrum of methyl formate has been observed in the 7-200 GHz region, and new 437 lines have been assigned to the first excited A torsional substate. Both excited state lines and ground state lines reported previously were analyzed simultaneously on the [...] Read more.
The microwave spectrum of methyl formate has been observed in the 7-200 GHz region, and new 437 lines have been assigned to the first excited A torsional substate. Both excited state lines and ground state lines reported previously were analyzed simultaneously on the basis of an internal axis method Hamiltonian. A total of 3514 lines were fitted to a 10th-order reduced Hamiltonian model involving 67 molecular parameters to a 1s standard deviation of 179 kHz. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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115 KiB  
Other
An Exploration of Dynamics of the Moving Mechanism of the Growth Cone
by Rubin Wang, Hatsuo Hayashi, Zhikang Zhang and Yun-Bo Duan
Molecules 2003, 8(1), 127-138; https://doi.org/10.3390/80100127 - 31 Jan 2003
Cited by 11 | Viewed by 9563
Abstract
A stochastic, nonlinear dynamic model is proposed to explain the growth cone at the tip of a cell process, such as a growing axon or dendrite of a neuron. The model explains the outward motion of the tip as an extension of the [...] Read more.
A stochastic, nonlinear dynamic model is proposed to explain the growth cone at the tip of a cell process, such as a growing axon or dendrite of a neuron. The model explains the outward motion of the tip as an extension of the cytoskeleton, using the actin- myosin system as a molecular motor. The kinetic energy is supplied by heat from ATP hydrolysis in the form of random motion of water molecules embedding the actin- myosin. The mechanical structure is provided by the F-actin macromolecules forming a spiral filament. The myosin heads form a stochastic distribution of small spheres. They are attached by elastic springs to the spiral rods of the myosin filaments. Under thermal agitation the system sustains oscillation, which is directed by the interaction between the myosin heads and the actin filament. As the energy of oscillation is dissipated, the actin filament is moved toward the center of the growth cone. The joint probability density of movement of the actin filament is obtained by solving a non-stationary version of the FPK equation. By incorporating a probability distribution of actin filaments provided by the geometry of the tip, the directed motion of the tip is explained. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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37 KiB  
Article
A New Potent Route of DNA Vaccine Inoculation: DNA-Liposome Complexes on Bare Skin Induce Antigen-Special Antibody Responses
by Rong Liang, Fengfeng Zhuang, Zheng Meng, Mingjun Deng, Changxue Zheng and Mingxing Duan
Molecules 2003, 8(1), 120-126; https://doi.org/10.3390/80100120 - 31 Jan 2003
Cited by 5 | Viewed by 10975
Abstract
Transcutaneous immunization is a novel strategy for genetic vaccine immunization to induce detectable antigen-special antibody in humor and mucosal. In this study, plasmid expressing hepatitis B surface antigen (pGFP-HBsAg) was encapsulated in liposome, then DNA- liposome complexes were glued on bare skin of [...] Read more.
Transcutaneous immunization is a novel strategy for genetic vaccine immunization to induce detectable antigen-special antibody in humor and mucosal. In this study, plasmid expressing hepatitis B surface antigen (pGFP-HBsAg) was encapsulated in liposome, then DNA- liposome complexes were glued on bare skin of mice ear in different dosage (50μg, 10μg and 1μg). As control, DNA- liposome complexes of pGFP-HBsAg and pGFP vector were inoculated intraperitoneally. The anti-HBsAg antibodies of serum were detected weekly by ELISA. It was found that the detectable antibodies of transcutaneous immunized mouse were elicited after four weeks, and reached a maximum at the sixth week. Even 1μg plasmid DNA in liposomes through immune skin can elicit the highest ELISA antibody titer (> 1:512) in test group, and corresponding percentage of positive response is up to 71% at sixth week, but higher amounts of plasmid DNA (50μg DNA per mice) on immune skin cannot induce higher antibody levels. The result showed that DNA- liposome complexes glued on bare skin appear to be a novel method for the administration of DNA vaccines. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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87 KiB  
Article
Microwave Spectrum of the Ethylmethyl Ether Molecule
by Shozo Tsunekawa, Yuji Kinai, Yuki Kondo, Hitoshi Odashima and Kojiro Takagi
Molecules 2003, 8(1), 103-119; https://doi.org/10.3390/80100103 - 31 Jan 2003
Cited by 8 | Viewed by 8516
Abstract
We have observed rotational transitions of ethylmethyl ether (CH3CH2OCH3) in the 24-110 GHz frequency range. We newly assigned the transitions of four Q-branch series for J=1-38 with Ka=0-5 and six R-branch series of b-type transitions for J=7-37 [...] Read more.
We have observed rotational transitions of ethylmethyl ether (CH3CH2OCH3) in the 24-110 GHz frequency range. We newly assigned the transitions of four Q-branch series for J=1-38 with Ka=0-5 and six R-branch series of b-type transitions for J=7-37 with Ka=0-3. All these assigned transitions were observed to be split into two or four components due to the internal rotations of the methyl groups. We analyzed the averaged frequencies of the split components on the basis of the Watson A-reduced Hamiltonian, neglecting the effect of the internal rotations. A total of 122 transitions were fitted to eight molecular parameters to a 1s standard deviation of 24 kHz. The parameters A, B, C and DJ were improved, and DJK, Dk, dJ and dK were determined for the first time. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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247 KiB  
Article
Sub-Doppler Spectroscopy by Use of Microwave Sidebands of CO2 Laser Lines Applied to the C-O Stretching Fundamental Band of Methanol
by Zhen-Dong Sun, Toru Mizuochi, Masanori Kaneko, Yoshiki Moriwaki, Fusakazu Matsushima and Kojiro Takagi
Molecules 2003, 8(1), 92-102; https://doi.org/10.3390/80100092 - 31 Jan 2003
Cited by 8 | Viewed by 10278
Abstract
Microwave sidebands of CO2 laser lines were used as an infrared source in infrared microwave double resonance spectroscopy and infrared saturation spectroscopy to study the C -O stretching fundamental band of methanol. In the former application, rotational lines in the vCO [...] Read more.
Microwave sidebands of CO2 laser lines were used as an infrared source in infrared microwave double resonance spectroscopy and infrared saturation spectroscopy to study the C -O stretching fundamental band of methanol. In the former application, rotational lines in the vCO = 1 state have been observed with good signal to noise ratios and physical processes involved in this method have been discussed. In the latter method, (vt, A/E, K) = (2, A, 4) sequence transitions in the C-O stretching fundamental band have been identified and term values for the (2, A, 4) levels in the vCO = 1 state have been determined. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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204 KiB  
Article
Atomic Force Microscope Imaging of the Aggregation of Mouse Immunoglobulin G Molecules
by Jiye Cai, Yao Chen, Qingcai Xu, Yong Chen, Tao Zhao, Xiaoyan Wang and Ke Xia
Molecules 2003, 8(1), 86-91; https://doi.org/10.3390/80100086 - 31 Jan 2003
Cited by 5 | Viewed by 9203
Abstract
Mouse immunoglobulin G (Ig G1 and the mixture of Ig G1 and Ig G2) deposited on mica were imaged with an atomic force microscope at room temperature and ambient pressure. At a concentration around 1.0mg/L, the molecules were well dispersed. 2~3 days after [...] Read more.
Mouse immunoglobulin G (Ig G1 and the mixture of Ig G1 and Ig G2) deposited on mica were imaged with an atomic force microscope at room temperature and ambient pressure. At a concentration around 1.0mg/L, the molecules were well dispersed. 2~3 days after sample preparation, both Ig G1 and the mixture could self- assemble into different shapes and further form some types of local-ordered toroidal aggregations (monotoroidal, intercrossed toroidal, concentric toroidal, etc.). The number of monomers was not identical in the different toroidal aggregations but in a same circle, the shapes of polymer self-assembled by several monomolecules were found to be almost the same. There was difference between the aggregation behavior of Ig G1 and the mixture. The mechanism of Ig G molecule aggregation was ascribed to the “Y” shape and loops structure of Ig G molecule. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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14 KiB  
Editorial
Editorial Note: Paper by Wroczynski et al.
by Derek J. McPhee
Molecules 2003, 8(1), 85; https://doi.org/10.3390/80100085 - 31 Jan 2003
Viewed by 5602
Abstract
The paper Determination of Aldehyde Dehydrogenase (ALDH) Isozymes in Human Cancer Samples – Comparison of Kinetic and Immunochemical Assays, by Piotr Wroczynski*, Jacek Wierzchowski, Jakub Golab, Magdalena Blazejczyk and Dorota Borecka, originally scheduled for publication in this special issue, was already published in [...] Read more.
The paper Determination of Aldehyde Dehydrogenase (ALDH) Isozymes in Human Cancer Samples – Comparison of Kinetic and Immunochemical Assays, by Piotr Wroczynski*, Jacek Wierzchowski, Jakub Golab, Magdalena Blazejczyk and Dorota Borecka, originally scheduled for publication in this special issue, was already published in an earlier one: Molecules 2002, 7, 896-901. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
178 KiB  
Article
A Method for Synthesizing Partially Substituted Cucurbit[n]uril
by Anthony I. Day, Alan P. Arnold and Rodney J. Blanch
Molecules 2003, 8(1), 74-84; https://doi.org/10.3390/80100074 - 31 Jan 2003
Cited by 134 | Viewed by 11119
Abstract
A novel approach to cucurbituril synthesis is described where partial substitution is introduced into cucurbit[n]uril. The identification of homologues (and their substitution) in reaction mixtures is achieved by a combination of ESMS and the use of the molecular probes (guests) 1,4-dioxane [...] Read more.
A novel approach to cucurbituril synthesis is described where partial substitution is introduced into cucurbit[n]uril. The identification of homologues (and their substitution) in reaction mixtures is achieved by a combination of ESMS and the use of the molecular probes (guests) 1,4-dioxane and 1,9-octanediamine. A unique symmetrical hexamethylcucurbit[3,3]uril, the major product, was isolated and characterized. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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455 KiB  
Article
Preparation and Characterization of Double Metal Cyanide Complex Catalysts
by Hanxia Liu, Xikui Wang, Yao Gu and Weilin Guo
Molecules 2003, 8(1), 67-73; https://doi.org/10.3390/80100067 - 31 Jan 2003
Cited by 19 | Viewed by 9611
Abstract
A series of double metal cyanide (DMC) complex catalysts were prepared in two different methods by using ß-cyclodextrin, PEG-1000 and Tween-60 as an additional complex ligands respectively. It was showed that a mixture of crystalline and amorphous DMC was synthesized by using traditional [...] Read more.
A series of double metal cyanide (DMC) complex catalysts were prepared in two different methods by using ß-cyclodextrin, PEG-1000 and Tween-60 as an additional complex ligands respectively. It was showed that a mixture of crystalline and amorphous DMC was synthesized by using traditional method in which the additional complex ligand was added after the precipitation of DMC. Amorphous and dispersed DMC with higher activity could be obtained when the additional complex ligand was added in the reactant solution before reaction. The effect of additional complex ligand and preparation method on the crystalline state and catalytic property of DMC were also investigated. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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85 KiB  
Review
The Chemistry of Isocyanides, their MultiComponent Reactions and their Libraries
by I. Ugi, B. Werner and A. Dömling
Molecules 2003, 8(1), 53-66; https://doi.org/10.3390/80100053 - 31 Jan 2003
Cited by 476 | Viewed by 22927
Abstract
The first century of isocyanide chemistry, which was then still a rather empty part of Organic Chemistry, began in 1859. In 1958 isocyanides became generally available by dehydration the formylamines. One year later the four component reaction of isocyanides (U-4CR) was introduced. This [...] Read more.
The first century of isocyanide chemistry, which was then still a rather empty part of Organic Chemistry, began in 1859. In 1958 isocyanides became generally available by dehydration the formylamines. One year later the four component reaction of isocyanides (U-4CR) was introduced. This one-pot reaction is accomplished just by mixing amines, carbonyl compounds, suitable acids and isocyanides. Most chemical reactions have their own ”scope and limitation”, whereas the U-4CR can convert almost all combinations of educts into their products. Until 1995 this chemistry was moderately used, but since then a new era of the U-4CR and its unions with further reactions have become increasingly popular, particularly as libraries. In industry this chemistry became one of its most often used methods of finding new desirable products. In contrast to most other areas of chemistry, isocyanide chemistry is not yet exhausted and still much progress can be expected there. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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44 KiB  
Other
Novel Easy Preparations of Some Aromatic Iodine(I, III, and V) Reagents, Widely Applied in Modern Organic Synthesis
by Lech Skulski
Molecules 2003, 8(1), 45-52; https://doi.org/10.3390/80100045 - 31 Jan 2003
Cited by 11 | Viewed by 7965
Abstract
We report our novel (or considerably improved) methods for the synthesis of aromatic iodides, (dichloroiodo)arenes, (diacetoxyiodo)arenes, [bis(trifluoroacetoxy)-iodo]arenes, iodylarenes and diaryliodonium salts, as well as some facile, oxidative anion metatheses in crude diaryliodonium or tetraalkylammonium halides and, for comparison, potassium halides. All our formerly [...] Read more.
We report our novel (or considerably improved) methods for the synthesis of aromatic iodides, (dichloroiodo)arenes, (diacetoxyiodo)arenes, [bis(trifluoroacetoxy)-iodo]arenes, iodylarenes and diaryliodonium salts, as well as some facile, oxidative anion metatheses in crude diaryliodonium or tetraalkylammonium halides and, for comparison, potassium halides. All our formerly published papers were discussed and explained in our review “Organic Iodine(I, III, and V) Chemistry: 10 Years of Development at the Medical University of Warsaw, Poland” (1990-2000) [1]. Our newest results are discussed below. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
93 KiB  
Article
Sonochemical Degradation Kinetics of Methyl Violet in Aqueous Solutions
by Xi Kui Wang, Guan Hong Chen and Wei Lin Guo
Molecules 2003, 8(1), 40-44; https://doi.org/10.3390/80100040 - 31 Jan 2003
Cited by 56 | Viewed by 10399
Abstract
The sonochemical degradation in aqueous solution of methyl violet, chosen as a model of a basic dye, was studied. The ultrasonic degradation kinetics in water were found to be first-order and the degradation rate coefficient is 1.35×10-2 min-1 (R= 0.9934, n=8) [...] Read more.
The sonochemical degradation in aqueous solution of methyl violet, chosen as a model of a basic dye, was studied. The ultrasonic degradation kinetics in water were found to be first-order and the degradation rate coefficient is 1.35×10-2 min-1 (R= 0.9934, n=8) at 20±1°C. The influence of the initial concentrations, reaction temperature and the pH of medium on the ultrasonic decomposition of methyl violet were also investigated. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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136 KiB  
Article
An EXAFS Study on the Local Structure Around Iron in Atmospheric Aerosols Collected in the Qingdao Area
by Jianhua Qi, Manping Zhang, Lijuan Feng, Xianguo Li, Zhi Xie, Zhihu Sun and Tiandou Hu
Molecules 2003, 8(1), 31-39; https://doi.org/10.3390/80100031 - 31 Jan 2003
Cited by 16 | Viewed by 12998
Abstract
The existing forms of Fe are of great interest since they have a profound effect on the biological availability of Fe. In this work, aerosol samples collected in different seasons and at different locations in the Qingdao region were examined by means of [...] Read more.
The existing forms of Fe are of great interest since they have a profound effect on the biological availability of Fe. In this work, aerosol samples collected in different seasons and at different locations in the Qingdao region were examined by means of extended X-ray absorption fine structure (EXAFS) K-edge analysis of Fe, X-ray diffraction (XRD) and Fe content analysis. The results showed that an iron ion in aerosol particles is surrounded on average by 5.8 (coordinated) O ions. For the six samples examined, the coordination number of the first Fe-O coordination subshell is always 3 with a coordination distance (with O) in the range of 1.952~1.966±0.002 Å, while the coordination number of the second subshell varies from 2.2 to 3.0 with a coordination distance of 2.108±0.002 Å. The coordination is approximately consistent with that of a-Fe2O3, suggesting that iron in aerosol samples is mainly present in the form of a-Fe2O3. The fact that the coordination number in the second subshell is smaller than that of a-Fe2O3 might be an indication that there is a small amount of FeO mixed with a-Fe2O3 in aerosol particles. Existence of FeO is confirmed by a later XRD experiment. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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389 KiB  
Article
Alcohol Synthesis over Pre-Reduced Activated Carbon-Supported Molybdenum-Based Catalysts
by Xianguo Li, Lijuan Feng, Lijun Zhang, Dady B. Dadyburjor and Edwin L. Kugler
Molecules 2003, 8(1), 13-30; https://doi.org/10.3390/80100013 - 31 Jan 2003
Cited by 34 | Viewed by 10779
Abstract
Activated carbon (AC)-supported molybdenum catalysts, either with or without a potassium promoter, were prepared by the incipient wetness impregnation method. The materials were characterized using differential thermal analysis (DTA) and temperature programmed reduction (TPR), and were used for mixed alcohol synthesis from syngas [...] Read more.
Activated carbon (AC)-supported molybdenum catalysts, either with or without a potassium promoter, were prepared by the incipient wetness impregnation method. The materials were characterized using differential thermal analysis (DTA) and temperature programmed reduction (TPR), and were used for mixed alcohol synthesis from syngas (CO+H2). DTA results showed that a new phase, related to the interaction between Mo species and the AC support, is formed during the calcination of the Mo/AC catalyst, and the introduction of a K promoter has noticeable effect on the interaction. TPR results indicated that the Mo is more difficult to reduce after being placed onto the AC support, and the addition of a K promoter greatly promotes the formation of Mo species reducible at relatively low temperatures, while it retards the generation of Mo species that are reducible only at higher temperatures. These differences in the reduction behavior of the catalysts are atributed to the interaction between the active components (Mo and K) and the support. Potassium-doping significantly promotes the formation of alcohols at the expense of CO conversion, especially to hydrocarbons. It is postulated that Mo species with intermediate valence values (averaged around +3.5) are more likely to be the active phase(s) for alcohol synthesis from CO hydrogenation, while those with lower Mo valences are probably responsible for the production of hydrocarbons. Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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The Societal Obligations of Universities
by Richard R. Ernst
Molecules 2003, 8(1), 2-12; https://doi.org/10.3390/80100002 - 31 Jan 2003
Cited by 2 | Viewed by 5505
Abstract
The questions I will discuss in my lecture are not specific to China, but rather apply to any country on the globe. They concern the relation between the academic community and society. Naturally, much of the hope for a better future is directed [...] Read more.
The questions I will discuss in my lecture are not specific to China, but rather apply to any country on the globe. They concern the relation between the academic community and society. Naturally, much of the hope for a better future is directed towards the sciences which provide the foundation for prosperous industries and for a higher standard of living. Without advanced and competitive science, nothing functions in any country, and adequate science support will be essential also for a healthy development of China. [...] Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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Editorial
Special Issue: Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002)
by Shu-Kun Lin and Derek J. McPhee
Molecules 2003, 8(1), 1; https://doi.org/10.3390/80100001 - 22 Jan 2003
Cited by 1 | Viewed by 6032
Abstract
We are pleased to launch Volume 8 of Molecules with a special issue containing a selection of lectures and papers presented at the ISFMS 2002 conference, co-sponsored by MDPI and hosted by the Ocean University of China last July 2002 at Qingdao, P.R [...] Read more.
We are pleased to launch Volume 8 of Molecules with a special issue containing a selection of lectures and papers presented at the ISFMS 2002 conference, co-sponsored by MDPI and hosted by the Ocean University of China last July 2002 at Qingdao, P.R China [1].[...] Full article
(This article belongs to the Special Issue Selected Papers from the International Symposium on Frontiers in Molecular Science (ISFMS 2002))
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