
	Where results make sense

Topic: Conformational isomerism

Related Topics

isomeric transitions

optically active isomer

In the News (Fri 1 Jun 12)

EXECUTIVE POWER

Iran

ANALYSIS

Pakistan

Family compact

	Conformational isomerism - Wikipedia, the free encyclopedia
		Conformational isomerism is the phenomenon of molecules with the same structural formula but different conformations (conformers) of atoms about a rotating bond.
		Conformational isomerism only occurs around single bonds as a result of the requirement of breaking one or more pi bonds to rotate substituents about a sigma bond axis in double and triple bonded atoms.
		Conformers sufficiently constrained to exhibit measurable isomerism are unique from various flavours of stereoisomers in the fact that changes in stereochemistry are independent from any mechanism and instead rely only on molecular energy.
	en.wikipedia.org /wiki/Conformational_isomerism (365 words)

	Isomer - Wikipedia, the free encyclopedia
		In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently.
		Isomerism was first noticed in 1825, when Friedrich Woehler prepared cyanic acid and noted that although its elemental composition was identical to fulminic acid (prepared by Justus von Liebig the previous year), its properties were quite different.
		This group includes chain isomerism whereby hydrocarbon chains have variable amounts of branching; position isomerism which deals with the position of a functional group on a chain; and functional group isomerism in which one functional group is split up into different ones.
	en.wikipedia.org /wiki/Isomer (588 words)

	Isomerism (Site not responding. Last check: 2007-10-17)
		Isomers are defined as molecules of identical atomic compositions (molecular formulas), but with different bonding arrangements of atoms or orientation of their atoms in space.
		Thus, the RS isomer is a diastereomer of the RR and SS isomers, and the SS isomer is a diastereomer of the RS and SR isomers.
		Conformational isomers are different three-dimensional arrangements in space of the atoms of a single compound or configurational isomer.
	www.dekker.com /sdek/162978895-340903/abstract~db=enc~content=a713491664~words= (3413 words)

	Stereoisomers (Site not responding. Last check: 2007-10-17)
		The bonding patterns of the atoms in these two isomers are essentially equivalent, the only difference being the relative orientation or configuration of the two methyl groups (and the two associated hydrogen atoms) about the double bond.
		In the cis isomer the methyl groups are on the same side; whereas they are on opposite sides in the trans isomer.
		In the staggered conformation there are six equal bond repusions, four of which are shown by the blue arrows, and these are all substantially less severe than the three strongest eclipsed repulsions.
	www.cem.msu.edu /~reusch/VirtualText4/sterisom.htm (2180 words)

	Encyclopedia: Chair conformation
		The chair conformation is a term used for the most stable chemical conformation of a six membered single bonded carbon ring like cyclohexane.
		In chemistry, a chemical conformation is the spatial arrangement of atoms in a molecule.
		Categories: Organic chemistry Conformational isomerism is the phenomenon of molecules with the same structural formula but different conformations (conformers) of atoms about a rotating bond.
	www.nationmaster.com /encyclopedia/Chair-conformation (341 words)

	Encyclopedia: Conformational isomerism
		In chemistry, the conformation of a molecule is its spatial configuration.
		In organic chemistry, a substituent is an atom or group of atoms subsituted in place of a hydrogen atom on the parent chain of a hydrocarbon.
		Geometry of the water molecule Molecules have fixed equilibrium geometries--bond lengths and angles--that are dictated by the laws of quantum mechanics.
	www.nationmaster.com /encyclopedia/Conformational-isomerism (782 words)

	A Dynamic NMR Investigation of the Conformational Isomerism in Novel 1,3,4,5-Tetrahydro-2,1-benzoxazepines
		It is clear that the slow isomerism at these temperatures involves flipping between energetically identical chair conformations similar to that observed in the solid state or predicted by AM1 calculations.
		Resonances for the major isomer (red) and minor isomer (blue) are depicted in the accompanying COSY spectrum of the aliphatic region.
		In both cases, the boat conformation turned out to be the highest in energy although the difference between boat and twist-boat forms for (1) was small whereas for the parent benzoxazepine (8) the twist-boat was only marginally higher in energy than the chair form.
	www.ch.ic.ac.uk /ectoc/echet96/papers/107 (2268 words)

	CHEM 331, Organic Chemistry I (Site not responding. Last check: 2007-10-17)
		If the total number of different substituents on a double bond is 2, geometric isomers may be classified as cis- or trans-.
		When the total number of substituents is 3 or 4, the isomers are classified as E or Z by assigning the order of priority of subsituents at each carbon of the double bond and giving an E designation to an alkene with the high priority substituents in a trans- configuration.
		CONFORMATIONAL ENANTIOMERS : Enantiomers that are interconvertable by internal inversion or by rotation around C-C bond when the barrier to these processes is low.
	www.towson.edu /~ryzhkov/handouts/stereo.html (826 words)

	Conformational isomerism Definition / Conformational isomerism Research (Site not responding. Last check: 2007-10-17)
		Conformational isomerism is the phenomenon of molecules with the same structural formulaMany chemical compounds, especially hydrocarbons, can exist in different geometric configurations.
		conformational isomerism is a phenomenon of very frequent occur-.
		conformational isomerism is a phenomenon of very frequent.
	www.elresearch.com /Conformational_isomerism (175 words)

	wiki/Conformational isomerism Definition / wiki/Conformational isomerism Research (Site not responding. Last check: 2007-10-17)
		EclipsedIn chemistry an eclipsed conformation is a chemical conformation that exists in any open chain single chemical bond connecting two sp3 hybridised atoms as a conformational energy maximum due to steric hindrance....
		If the eclipsed conformations of an isomerIn chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently.
		Conformational isomerism only occurs around single bonds as a result of the requirement of breaking one or more pi bondsIn chemistry, Pi bonds are those bonds between two atoms in a molecule that do not exhibit orbital hybridization.
	www.elresearch.com /wiki/Conformational_isomerism (1227 words)

	eLibrary Project : Isomer (Site not responding. Last check: 2007-10-17)
		Sitemap > I > Is > Iso > Isom > Isomer
		In chemistry, "isomers" are molecules with the same chemical formula and often with the same kinds of chemical bond,bonds between atoms, but in which the atoms are arranged differently.
		In the example above it should also be noted that in both isomers all the bonds are covalent bonding,single bonds; there is no ''type'' of bond that appears in one isomer and not in the other.
	elibraryproject.com /info/isomer.html (1341 words)

	[No title]
		"Conformational Analysis of 1-Chloro-4-iodobutane and 1-Chloro- 5-iodopentane," G. Crowder and Syed Ali, J. Mol.
		"Conformational Analysis of 2-Chloro-4-methylpentane and 2- Bromo-4-methylpentane," G. Crowder and R. Jaiswal, J. Mol.
		"Conformational and Vibrational Analysis of 2-Pentyne and 2- Hexyne," G. Crowder and Pat Blankenship, J. Mol.
	www.chem.latech.edu /chemistry_people/crowder (2221 words)

	Computational Dispersion Rheology: research, reaction rates (Site not responding. Last check: 2007-10-17)
		We study the isomerisation reaction of calix[4]arenes (cyclic arrays of four phenol groups, see picture on the right) in vacuum and in solvent.
		In an isomerisation, a phenol rotates around the two methyl "hinges" by which it is connected to the rest of the molecule.
		Isomerisations are rare compared to the normal vibrational and rotational dynamics of the system, as they occur just once every 10 ms.
	www.tn.utwente.nl /cdr/Research/reaction.html (369 words)

	Atropisomerism, molecular rotors and highly-polarizable molecules (Site not responding. Last check: 2007-10-17)
		Usually, the interconversion between the two conformers is accomplished by rotation of a functional group around a single bond.
		Thus, these isomers are a special class of rotamers for which the energy barrier of rotation is large enough to prevent a rapid interconversion of the isomers at room temperature but small enough to overcome under special conditions, as an increase in temperature or, if in solution, by interaction with solvent molecules.
		An x-ray study of the conformation of tricine in the molecular crystal of the pure compound was undertaken.
	pollux.fis.uc.pt /rel00/node9.html (968 words)

	Department of Chemistry (Site not responding. Last check: 2007-10-17)
		Configuration and conformational isomerism in simple aliphatic compounds; Chirality and elements of symmetry (axis, centre and plane).
		Conformational analysis of cyclohexane, mono- and di-substituted cyclohexane, two-fused six-membered rings leading to steroid structure and nomenclature.
		Influence of conformation and axial an equatorial orientation on reactivity.
	www.uz.ac.zw /science/chemistry/courses/ch213.htm (230 words)

	Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. (Site not responding. Last check: 2007-10-17)
		H NMR of 2,6-diaryl-1-hydroxy piperidin-4-one oximes; substituent effects on cis/trans ratio and conformational equilibria, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 56 (11) (2000) pp.
		H.M. Badawi, W. Forner, Conformational analysis and comparison between theoretical and experimental vibrational spectra for chloroacetyl isocyanate, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 59 (2) (2003) pp.
		Conformational IR Alina T. Dubis, Sawomir J. Grabowski, Vibrational spectrum of methyl pyrrole-2-carboxylate, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 58 (1) (2002) pp.
	www.elsevier.com /cdweb/journals/13861425/viewer.htt?viewtype=keywords&rangeselected=55 (1265 words)

	Publications
		Conformational Analysis of Beta-Methylphenylalanine Stereoisomers of DPDPE using NMR Data and Conformational Energy Calculations.
		Acetyl-(3- and 4-alkylthiolprolyl31)-CCK4 analogs: synthesis and implications for the CCK-B receptor-bound conformation.
		Development of models for the bioactive conformations of ligands for CCK A and B receptors and their use in the design and synthesis of highly potent and selective analogs.
	www.cmd.wustl.edu /GNwebdocs/Publications.htm (1804 words)

	Folding funnels and binding mechanisms -- Ma et al. 12 (9): 713 -- Protein Engineering Design and Selection
		that the ensembles of conformational isomers, populating the
		The conformer which is crystallized is the one whose conformation is favorable for binding under these conditions, with the equilibrium shifting in its favor.
		Conformational isomerism is a general phenomenon, borne by the
	peds.oupjournals.org /cgi/content/full/12/9/713 (5150 words)

	Conformational Correction Mechanisms Aiding Antigen Recognition by a Humanized Antibody -- Holmes et al. 187 (4): 479 ... (Site not responding. Last check: 2007-10-17)
		Conformational Correction Mechanisms Aiding Antigen Recognition by a Humanized Antibody -- Holmes et al.
		Conformational Correction Mechanisms Aiding Antigen Recognition by a Humanized Antibody
		conformations are also nearly identical in the complexed structures.
	www.jem.org /cgi/content/full/187/4/479 (3037 words)

	Conformations of the regulatory domain of cardiac troponin C examined by residual dipolar couplings -- ... (Site not responding. Last check: 2007-10-17)
		Conformations of the regulatory domain of cardiac troponin C examined by residual dipolar couplings -- Pääkkönen et al.
		Conformations of the regulatory domain of cardiac troponin C examined by residual dipolar couplings
		The direct comparisons of measured dipolar couplings to the corresponding conformations are indicated by bold type whereas the figures of merit for the cross comparisons are shown by normal type setting.
	www.ejbiochem.org /cgi/content/full/267/22/6665 (4732 words)

	IngentaConnect Conformational Isomerism and Chlorotropy Mechanisms of Chlorometh... (Site not responding. Last check: 2007-10-17)
		IngentaConnect Conformational Isomerism and Chlorotropy Mechanisms of Chlorometh...
		Conformational Isomerism and Chlorotropy Mechanisms of Chloromethyl- and Trichloromethyldichlorophosphines
		The ylide and phosphinic chlorotropic isomers for I and II are thermodynamically stable with greater stability found for II.
	www.ingentaconnect.com /content/klu/thec/2001/00000037/00000003/00362342 (258 words)

	Introduction to Pharmaceutical Stereochemistry - London University School of Pharmacy (Site not responding. Last check: 2007-10-17)
		E and Z labelling is covered and the chemical and physical properties of geometric isomers.
		The student is introduced to the isomerism displayed by asymmetric carbon atoms, Fishcer notation and the representation of three dimensions as two.
		Properties of optical isomers together with optical rotation are covered, as are compounds with more than one asymmetric carbon and the D and L labelling method.
	www.le.ac.uk /tltp/catalogue/phase1/tom13201.htm (430 words)

	Chemistry 3 Course Web Site - Lectures (Site not responding. Last check: 2007-10-17)
		To study the shape of organic molecules in three dimensions and appreciate that the conformation of a molecule dictates how it will react.
		Alicyclics in nature, nomenclature, dependence of physical and chemical properties on conformation.
		The effect of conformation on elimination and rearrangement reactions in six membered rings.
	www.chem.ed.ac.uk /teaching/undergrad/chemistry3/lectures/g2t5_ca.html (167 words)

	Abstracts: Methyl CyanoAcetate / Physical Chemistry Chemical Physics (Site not responding. Last check: 2007-10-17)
		Conformational isomerism in methyl cyanoacetate: A combined matrix-isolation infrared spectroscopy and molecular orbital study.
		The conformational isomerization processes in MCA in the temperature range from 10 to 70 K were studied in detail in argon and xenon matrixes.
		The matrix isolation spectroscopic data indicate that interconversion between the gauche conformers occurs even in the low temperature matrixes.
	www.qui.uc.pt /~reva/ABST/mca-ab.htm (284 words)

	PSIgate - Physical Sciences Information Gateway: Search/Browse Results (Site not responding. Last check: 2007-10-17)
		Cis and trans isomerism are discussed, together with sequence isomerism, and stereoisomerism considering isotactic, syndiotactic and atactic configurations of a polymer molecule.
		The topics reviewed are: isomerism, constitutional isomers, stereoisomerism, enantiomers (resolution, properties and nomenclature), optically active natural products, specific rotation, racemic mixtures, asymmetric centres, stereogenic centres, polarimeters, plane-polarised light, optical activity, determination of priority, chirality and diastereomers.
		Formulae, structures and brief notes are provided on aspects of organic chemistry, including: functional groups, structural isomers, stereoisomerism, geometrical (cis-trans) isomerism, optical isomerism, optical activity and racemic mixtures, Grignard reagents, reactions of carboxylic acids, esters, carbonyl compounds, ethanoyl chloride, primary amines with hydrogen ions, amides, and amino acids.
	www.psigate.ac.uk /roads/cgi-bin/psisearch.pl?term1=isomerism&limit=0&subject=All (1453 words)

Try your search on: Qwika (all wikis)