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Molecules, Volume 8, Issue 2 (February 2003), Pages 223-296

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Open AccessArticle The 3-Attractor Water Model: Monte-Carlo Simulations with a New, Effective 2-Body Potential (BMW)
Molecules 2003, 8(2), 226-242; doi:10.3390/80200226
Received: 18 August 2002 / Accepted: 9 September 2002 / Published: 14 February 2003
Cited by 5 | PDF Full-text (322 KB) | HTML Full-text | XML Full-text
Abstract
According to the precepts of the 3-attractor (3-A) water model, effective 2-body water potentials should feature as local minima the bifurcated and inverted water dimers in addition to the well-known linear water dimer global minimum. In order to test the 3-A model, [...] Read more.
According to the precepts of the 3-attractor (3-A) water model, effective 2-body water potentials should feature as local minima the bifurcated and inverted water dimers in addition to the well-known linear water dimer global minimum. In order to test the 3-A model, a new pair wise effective intermolecular rigid water potential has been designed. The new potential is part of new class of potentials called BMW (Bushuev-Muguet-Water) which is built by modifying existing empirical potentials. This version (BMW v. 0.1) has been designed by modifying the SPC/E empirical water potential. It is a preliminary version well suited for exploratory Monte-Carlo simulations. The shape of the potential energy surface (PES) around each local minima has been approximated with the help of Gaussian functions. Classical Monte Carlo simulations have been carried out for liquid water in the NPT ensemble for a very wide range of state parameters up to the supercritical water regime. Thermodynamic properties are reported. The radial distributions functions (RDFs) have been computed and are compared with the RDFs obtained from Neutron Scattering experimental data. Our preliminary Monte-Carlo simulations show that the seemingly unconventional hypotheses of the 3-A model are most plausible. The simulation has also uncovered a totally new role for 2-fold H-bonds. Full article
Open AccessArticle Synthesis and X-ray Crystal Structure of Meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1,8-di-(1-methylnaphthalene)
Molecules 2003, 8(2), 243-250; doi:10.3390/80200243
Received: 19 December 2002 / Revised: 12 January 2003 / Accepted: 13 January 2003 / Published: 28 February 2003
Cited by 2 | PDF Full-text (76 KB) | HTML Full-text | XML Full-text
Abstract
The pendant-arm macrocycle, meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1,8-di-(1-methylnaphthalene) has been synthesized and its single crystal structure determined. The molecule crystallizes in a primitive monoclinic cell, with the space group P21/a (#14). The cell dimensions are a = 10.778(3)Å, b = 13.809(3) Å, c [...] Read more.
The pendant-arm macrocycle, meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1,8-di-(1-methylnaphthalene) has been synthesized and its single crystal structure determined. The molecule crystallizes in a primitive monoclinic cell, with the space group P21/a (#14). The cell dimensions are a = 10.778(3)Å, b = 13.809(3) Å, c = 11.420(2) Å, = 102.49(2)°, volume = 1659.5(6) Å3. Full article
Open AccessArticle Regioselective Ethanolamination and Ketalization of 3-Ph-2,4-diacetyl(diethoxycarbonyl)-5-hydroxy-5-methylcyclohexanones
Molecules 2003, 8(2), 251-255; doi:10.3390/80200251
Received: 16 November 2002 / Revised: 24 January 2003 / Accepted: 26 January 2003 / Published: 28 February 2003
Cited by 5 | PDF Full-text (279 KB) | HTML Full-text | XML Full-text
Abstract The reaction of 3-phenyl-2,4-diacetyl(diethoxycarbonyl)-5-hydroxy-5-methylcyclohexanones with ethanolamine and ethylene glycol proceeds regioselectively using the carbonyl group of the alicycle to produce the corresponding cyclohexenylethanolamines and dioxolanes. Full article
Open AccessArticle Effect of Microwaves in the Chiral Switching Asymmetric Michael Reaction
Molecules 2003, 8(2), 256-262; doi:10.3390/80200256
Received: 20 May 2002 / Revised: 20 February 2003 / Accepted: 21 February 2003 / Published: 28 February 2003
Cited by 5 | PDF Full-text (37 KB) | HTML Full-text | XML Full-text
Abstract Highly enantioselective Michael reactions of malonates with cyclic enones are achieved in remarkably less time under microwave irradiation using newly developed heterobimetallic catalysts. Full article
Open AccessArticle Synthesis of 2-(2-R1-Hydrazino)-5-(R2-benzyl)-2-thiazolines on the Basis of Meerweins Arylation Products of Allyl Isothiocyanate
Molecules 2003, 8(2), 263-268; doi:10.3390/80200263
Received: 12 July 2002 / Revised: 20 February 2003 / Accepted: 21 February 2003 / Published: 28 February 2003
Cited by 2 | PDF Full-text (30 KB) | HTML Full-text | XML Full-text
Abstract 3-Aryl-2-chloropropylisothiocyanates (1) are formed by interaction of arenediazonium chlorides with allyl isothiocyanate. Adducts 1 react with monoacylhydrazines to form 1-acyl-4-(3-aryl-2-chloropropyl)thiosemicarbazides (2a–d). Thiosemicarbazides 2a–d in the presence of bases selectively transform into 2-(2-R1-hydrazino)-5-(R2-benzyl)-2-thiazolines (3a–d). Full article
Open AccessArticle Crystal Structure of N,N,N’,N’-tetra-[(3,5-dimethyl-1-pyrazolyl) methyl]-para-phenylenediamine
Molecules 2003, 8(2), 269-274; doi:10.3390/80200269
Received: 27 May 2002 / Revised: 10 February 2003 / Accepted: 17 February 2003 / Published: 28 February 2003
Cited by 8 | PDF Full-text (102 KB) | HTML Full-text | XML Full-text
Abstract
The title compound, molecular formula C30H40N10, crystallizes and exhibits a cisoidal conformation around a central p-phenylenediamine ring suggesting that this bis-tripodal ligand is highly flexible and could be accommodated by many and original metal coordinations. All [...] Read more.
The title compound, molecular formula C30H40N10, crystallizes and exhibits a cisoidal conformation around a central p-phenylenediamine ring suggesting that this bis-tripodal ligand is highly flexible and could be accommodated by many and original metal coordinations. All four five-membered pyrazole rings are identical. The molecule presents an inversion centre that coincides with the phenyl ring centre: pyrazole rings are two-by-two equivalent. The electrostatic spatial intramolecular repulsion between N4 and N5 is probably responsible for this general arrangement. These data emphasize the basic character of nitrogens N4 and N5. Full article
Open AccessArticle Synthesis and Biological Evaluation of Some New Coumarin Derivatives
Molecules 2003, 8(2), 275-286; doi:10.3390/80200275
Received: 21 September 2002 / Revised: 12 January 2003 / Accepted: 15 February 2003 / Published: 28 February 2003
Cited by 58 | PDF Full-text (57 KB) | HTML Full-text | XML Full-text
Abstract
Pyrimidino[5`,4`-6,5]-,pyridino[3`,2`-6,5]- and pyrrolo[3`,2`-5,6]4H-pyrano-[3,2-c][1]benzopyran-6-one derivatives (5-7 and 10) could be obtained via reaction of 2-amino-4-(p-bromophenyl)-3-cyano(carboethoxy)-4H,5H-pyrano[3,2-c][1]benzopyran-5-ones (3a,b) with a variety of reagents. Alkylation of (3b) with either 2-furoyl chloride or chloroacetyl chloride gave the 2-N-substituted derivatives (9a,b). Benzofurano[3,2-b]4H-pyran derivative (12) was also prepared. The [...] Read more.
Pyrimidino[5`,4`-6,5]-,pyridino[3`,2`-6,5]- and pyrrolo[3`,2`-5,6]4H-pyrano-[3,2-c][1]benzopyran-6-one derivatives (5-7 and 10) could be obtained via reaction of 2-amino-4-(p-bromophenyl)-3-cyano(carboethoxy)-4H,5H-pyrano[3,2-c][1]benzopyran-5-ones (3a,b) with a variety of reagents. Alkylation of (3b) with either 2-furoyl chloride or chloroacetyl chloride gave the 2-N-substituted derivatives (9a,b). Benzofurano[3,2-b]4H-pyran derivative (12) was also prepared. The antimicrobial activity of the prepared compounds was tested. Full article
Open AccessArticle Synthesis, Crystal Structure, Stacking Effect and Antibacterial Studies of a Novel Quaternary Copper (II) Complex with Quinolone
Molecules 2003, 8(2), 287-296; doi:10.3390/80200287
Received: 1 January 2003 / Published: 28 February 2003
Cited by 37 | PDF Full-text (302 KB) | HTML Full-text | XML Full-text
Abstract
The structural properties of a new copper (II) complex [Cu2(cip)2(bpy)2(pip)]·6H2O (bpy=2,2’-bipyridyl, cip=1-cyclopropyl-6-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, pip= piperazinyl anion), obtained during the synthesis of the copper complex with ciprofloxacin (cpf), has been investigated. The complex crystallizes in [...] Read more.
The structural properties of a new copper (II) complex [Cu2(cip)2(bpy)2(pip)]·6H2O (bpy=2,2’-bipyridyl, cip=1-cyclopropyl-6-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, pip= piperazinyl anion), obtained during the synthesis of the copper complex with ciprofloxacin (cpf), has been investigated. The complex crystallizes in the triclinic system, space group P-1. The cell dimensions are: a=6.874(2) Å, b= 10.761(3) Å, c= 17.969(5) Å, α =80.071(6)°, β= 85.253(6)°, γ=79.109(6)°,V=1284.5(6) Å3, and Z=2. The Cu (II) ion displays a five-coordinate square pyramidal coordination with two nitrogen donors from bpy, the 4-keto and 3-carboxylate oxygen donors of cip, and the third nitrogen atom of the pip anion occupying the fifth site. There is a stack effect between cip ring and bpy ring from another molecule, where the stacking distance is about 3.5 Å. The results of elemental analysis and FT-IR measurement are also included. Both ligand and complex were assayed against gram-positive and gram-negative bacteria by the doubling dilutions method. The complex shows the same minimal inhibitory concentration (MIC) against S. Aureus and E. Coli bacteria as the corresponding ligand. Full article

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Open AccessNew Book Received Biodiversity of Microbial Life: Foundation of Earth's Biosphere
Molecules 2003, 8(2), 223-225; doi:10.3390/80200223
Received: 1 September 2002 / Published: 14 February 2003
PDF Full-text (114 KB) | HTML Full-text | XML Full-text

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