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Dimethylamino

Distribution by Scientific Domains

Chemistry	72%
Polymers and Materials Science	21%
Medical Sciences	2%
Life Sciences	2%

Distribution within Chemistry

Organic Chemistry	34%
General & Introductory Chemistry	15%
Pharmaceutical & Medicinal Chemistry	4%
15 Other Subdomains	47%

Selected Abstracts

Two- and Three-Dimensional Hydrogen-Bonded Networks Built from 1,3,5-[(HO)2(O)P]3C6H3 and 4-(Dimethylamino)pyridine

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2004
Michael Mehring
Abstract Crystallisation of 3,5-bis(phosphonophenyl)phosphonic acid, 1,3,5-[(HO)2(O)P]3C6H3, from MeOH/H2O in the presence of 4-(dimethylamino)pyridine, 4-(Me2N)C5H4N, gave [1-{(HO)2(O)P}-3,5-{(HO)(O)2P}2C6H3]2,[{4-(Me2N)C5H4NH}+]2 (2) and [1,3-{(HO)2(O)P}2 -5-{(HO)(O)2P}C6H3],[4-(Me2N)C5H4NH]+ (3). Single-crystal X-ray diffraction analyses revealed a two- and a three-dimensional hydrogen-bonded network for compounds 2 and 3, respectively. Compound 2 is composed of layers which are formed by hydrogen-bonded motifs of the type R2,2(8) and R4,4(16). These motifs are connected within the layer by additional hydrogen bonds and the benzene spacer. The cation [4-(Me2N)C5H4NH]+ is located between the layers and determines the interlayer separation of approximately 6.5 Å. In compound 3 a layered network of the hydrogen-bonded building units R2,3(10) was observed. These units are interconnected by four additional hydrogen bonds within the network. The benzene spacer links the adjacent layers to give a three-dimensional structure. Within this network, channels with internal dimensions of ca. 8.5 × 11.3 Å2 which are occupied by the [4-(Me2N)C5H4NH]+ cations were observed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Synthesis and Dynamic Features of (Chloro)zirconocene Cations Stabilised by Pendant (Diarylphosphanyl)alkyl and (Dimethylamino)alkyl Substituents at Their Cyclopentadienyl Ring Systems

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2003
Steve Döring
Abstract Treatment of the substituted (diarylphosphanyl)methyl group-4 metallocene complexes [(C5H4,CR1R2,PAr2)2ZrCl2] (2: R1/R2 = CH3/CH3, H/CH3, H/aryl) with Li[B(C6F5)4] in dichloromethane solution results in chloride ligand abstraction (with LiCl precipitation) to yield the complexes [(C5H4,CR1R2,PAr2)2Zr,Cl+] (5), with both phosphanyl groups internally coordinated to the metal centre. Three possible diastereoisomers are observed in the case of 5c (R1 = H; R2 = CH3), while bulkier R2 substituents give higher selectivities. The thermally induced (reversible) cleavage of the Zr,phosphane linkage results in dynamic NMR behaviour. Gibbs activation energies of ,G,(298 K) = 14.8 ± 0.5 and 14.5 ± 0.5 kcal/mol were obtained for these intramolecular equilibration processes in the complexes trans - 5d (R1 = H; R2 = Ph) and trans - 5e (R1 = H; R2 = ferrocenyl), respectively. Treatment of the substituted (dimethylamino)methyl metallocene complexes [(C5H4,CR1R2,NMe2)2ZrCl2] (6a, 6b) with Li[B(C6F5)4] proceeds analogously to yield the cation systems [{C5H4,C(CH3)2,NMe2}2ZrCl+] (12a) and [{C5H4,CH(CH3),NMe2}2ZrCl+] (12b, three possible diastereoisomers). Both complexes have their pairs of amino groups coordinated to the metal centre. The complexes exhibit dynamic NMR spectra. Selective equilibration of the diastereotopic N(CH3)A(CH3)B resonances of complex 12a is observed [,G,(233 K) = 11.5 ± 0.2 kcal/mol], whereas the adjacent C(CH3)A(CH3)B methyl groups remain diastereotopic. The dynamic equilibration of the latter was observed at a markedly higher temperature [,G,(333 K) = 17.3 ± 0.2 kcal/mol]. Treatment of [{C5H4,C(CH3)2,NMe2}CpZrCl2] (10) with Li[B(C6F5)4] resulted in the formation of complex [{C5H4,C(CH3)2,NMe2}CpZr,Cl+] (11), which shows the internal ,N(CH3)A(CH)B equilibration proceeding with a markedly higher activation barrier [,G,(333 K) = 17.6 ± 0.2 kcal/mol] than in 12a, and a stereochemical memory effect indicative of solvent coordination to the metal centre of the resulting highly electrophilic chlorozirconocene cation intermediate. Complex 11 was characterised by an X-ray crystal structure analysis, which shows the internal Zr,amine coordination. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

Visible-Light Photoresponsivity of a 4-(Dimethylamino)azobenzene Unit Incorporated into Single-Stranded DNA: Demonstration of a Large Spectral Change Accompanying Isomerization in DMSO and Detection of Rapid (Z)-to-(E) Isomerization in Aqueous Solution

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2007
Takashi Kamei
Abstract We demonstrate significant visible-light photoresponsivity in a synthesized oligonucleotide containing a built-in pseudo-nucleotide possessing a 4-(dimethylamino)azobenzene (4-DMAzo) side chain. In dry DMSO as solvent, two clearly distinguishable spectra corresponding to the (E) and (Z) forms of the 4-DMAzo moiety tethered to the oligonucleotide were recorded with a conventional spectrophotometer before and after irradiation with 420 nm wavelength light, which induced (E)-to-(Z) isomerization. In addition, (Z)-to-(E) isomerization was accelerated by irradiation with either visible (, = 550 nm) or UV (, = 350 nm) light, demonstrating reversible photoresponsivity of the pseudo-oligonucleotide. In aqueous solutions the (Z)-to-(E) thermal isomerization of the photoresponsive pseudo-oligonucleotide was very rapid and was only detectable by laser flash photolysis.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Transformations of Methyl 2-[(E)-2-(Dimethylamino)-1-(methoxycarbonyl)ethenyl]-1-methyl-1H -indole-3-carboxylate

HELVETICA CHIMICA ACTA, Issue 11 2006
David Bevk
Abstract A simple and efficient synthesis of novel 2-heteroaryl-substituted 1H -indole-2-carboxylates and , -carbolines, compounds 1,3, from methyl 2-(2-methoxy-2-oxoethyl)-1-methyl-1H -indole-3-carboxylate (4) by the enaminone methodology is presented. [source]

Enantioselective Synthesis of 4-(Dimethylamino)pyridines through a Chemical Oxidation-Enzymatic Reduction Sequence.

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2006
Application in Asymmetric Catalysis
Abstract Enantiomerically pure 4-(dimethylamino)-3-(1-hydroxyalkyl)pyridines and 4-(dimethylamino)-3-[hydroxy(phenyl)methyl]pyridine have been prepared through efficient chemoenzymatic routes. For this purpose different lipases and oxidoreductases have been tested in the preparation of optically active 4-chloro derivatives and baker's yeast was found to be an excellent catalyst for the bioreductions of the corresponding ketones. Their applications as enantioselective nucleophilic catalysts have been studied, important catalytic properties were observed in the stereoselective construction of quaternary centers. [source]

Synthesis and structural analysis of 1,4-bis[n -(N,N -dimethylamino)phenyl]buta-1,3-diynes and charge-transfer complexes with TCNE

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2001
J. Gonzalo Rodríguez
Abstract n -(N,N -Dimethylamino)phenylethynes were satisfactorily prepared by a Wittig reaction between chloromethylene(triphenyl)phosphine ylide and the appropriate n -(N,N -dimethylamino)benzaldehyde, followed by dehydrochlorination with a strong base. The conjugate dimers 1,4-bis[n -(N,N -dimethylamino)phenyl]buta-1,3-diyne were obtained by oxidative dimerization with copper(I) chloride. X-ray molecular structure analysis of the dimer 1,4-bis[2 -(N,N -dimethylamino)phenyl]buta-1,3-diyne corroborated the resonance contribution of the o -dimethylamino substituent, which was confirmed in the solid state by the molecular crystalline packing. Both o - and p -(N,N -dimethylamino) conjugate dimers develop 1:1 charge-transfer complexes with TCNE and their structure was identified by NMR, IR and UV,visible spectroscopic data. Differential scanning calorimetric analyses of the 1,3-diynes showed an irreversible transformation to a thermopolymer as a unimolecular reaction. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Synthesis of a New Macromonomer from 2-(Dimethylamino)ethyl Methacrylate Bearing 1-(Isopropenylphenyl)-1,1-dimethylmethyl Isocyanate Group

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 5 2004
Cyril Boyer
Abstract Summary: The telomerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) with 2-mercaptoethanol in acetonitrile shows that the telogen can react with the monomer by nucleophilic addition. It is to say that the tertiary amino group leads to nucleophilic addition rather than telomerization. The oligomers thus obtained were functionalized with 1-(isopropenylphenyl)-1,1-dimethylmethyl isocyanate (TMI) in anhydrous toluene to afford macromonomers. These macromonomers were copolymerized with styrene and the r1, r2 ratio was determined according to Jaacks and Macret's methods. It was thereby demonstrated that the r1 value for this type of monomer is close to zero. Structure of the model molecule. [source]

Synthesis and Pharmacological Evaluation of N -(Dimethylamino)ethyl Derivatives of Benzo- and Pyridopyridazinones

ARCHIV DER PHARMAZIE, Issue 1 2009
Wanda Pakulska
Abstract New N -(dimethylamino)ethyl derivatives of phthalazinones and pyridopyridazinones 7, 9 were synthesized and assayed as potential analgesic agents in the hot-plate, tail-flick, and writhing tests. Pharmacological assay demonstrated that eight (in ten) of the newly synthesized compounds showed antinociceptive activity. Especially, 2-[2-(dimethylamino)ethyl]-4-phenyl-2H -phthalazin-1-one 7a showed remarkably higher antinociceptive activity in all tests. This is connected with influence on supraspinal, spinal, and peripheral structures. The decreased sensitivity to the pain stimulus in the hot-plate was higher than that of metamizole. [source]

ChemInform Abstract: About the Reaction of ,-Dimethylamino-,,,-enones with Active Methylene Nitriles.

CHEMINFORM, Issue 6 2010
Fathy M. Abdelrazek
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: Ring-Opening/Recyclization Reactions of (Dimethylamino)propenoyl-Substituted Cyclopropanes: Facile Synthesis of Halogenated Pyridin-2(1H)-ones.

CHEMINFORM, Issue 51 2009
Rui Zhang
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: [2 + 2] Cycloadditions of Electron-Poor Acetylenes to (5Z)-5-[(Dimethylamino)methylene]imidazolidine-2,4-diones.

CHEMINFORM, Issue 29 2009
Uros Ursic
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: p-(Dimethylamino)benzaldehyde Modification of the Hantzsch Reaction: Synthesis of 3-(1H-Benzimidazol-2-yl)-5,7-dimethoxyquinolines.

CHEMINFORM, Issue 38 2008
I. B. Dzvinchuk
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Asymmetric Synthesis of anti-Homopropargylic Alcohols from Aldehydes and Chiral Sulfonimidoyl Substituted Bis(allyl)titanium Complexes Through Generation and Elimination of Novel Chiral Alkylidenecarbene (Dimethylamino)sulfoxonium Ylides.

CHEMINFORM, Issue 2 2003
Leleti Rajender Reddy
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

ChemInform Abstract: Efficient Synthesis of N-3-Substituted 6-Aminouracil Derivatives via N6 -[(Dimethylamino)methylene] Protection.

CHEMINFORM, Issue 28 2001
Eva-Maria Priego
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Mechanistic Investigation of the Dipolar [2+2] Cycloaddition,Cycloreversion Reaction between 4-(N,N -Dimethylamino)phenylacetylene and Arylated 1,1-Dicyanovinyl Derivatives To Form Intramolecular Charge-Transfer Chromophores

CHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2010
Yi-Lin Wu
Abstract The kinetics and mechanism of the formal [2+2] cycloaddition,cycloreversion reaction between 4-(N,N -dimethylamino)phenylacetylene (1) and para -substituted benzylidenemalononitriles 2,b,2,l to form 2-donor-substituted 1,1-dicyanobuta-1,3-dienes 3,b,3,l via the postulated dicyanocyclobutene intermediates 4,b,4,l have been studied experimentally by the method of initial rates and computationally at the unrestricted B3LYP/6-31G(d) level. The transformations were found to follow bimolecular, second-order kinetics, with =13,18,kcal,mol,1, ,,30,cal,K,1,mol,1, and =22,27,kcal,mol,1. These experimental activation parameters for the rate-determining cycloaddition step are close to the computational values. The rate constants show a good linear free energy relationship (,=2.0) with the electronic character of the para -substituents on the benzylidene moiety in dimethylformamide (DMF), which is indicative of a dipolar mechanism. Analysis of the computed structures and their corresponding solvation energies in acetonitrile suggests that the rate-determining attack of the nucleophilic, terminal alkyne carbon onto the dicyanovinyl electrophile generates a transient zwitterion intermediate with the negative charge developing as a stabilized malononitrile carbanion. The computational analysis predicted that the cycloreversion of the postulated dicyanocyclobutene intermediate would become rate-determining for 1,1-dicyanoethene (2,m) as the electrophile. The dicyanocyclobutene 4,m could indeed be isolated as the key intermediate from the reaction between alkyne 1 and 2,m and characterized by X-ray analysis. Facile first-order cycloreversion occurred upon further heating, yielding as the sole product the 1,1-dicyanobuta-1,3-diene 3,m. [source]

Nucleophilicities and Carbon Basicities of Pyridines

CHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2007
Frank Brotzel Dipl.-Chem.
Abstract Rate and equilibrium constants for the reactions of pyridines with donor-substituted benzhydrylium ions have been determined spectrophotometrically. The correlation equation log,k(20,°C)=s(N+E), in which s and N are nucleophile-specific parameters and E is an electrophile-specific parameter, has been used to determine the nucleophilicity parameters of various pyridines in CH2Cl2 and aqueous solution and to compare them with N of other nucleophiles. It is found that the nucleophilic organocatalyst 4-(dimethylamino)pyridine (DMAP) and tertiary phosphanes have comparable nucleophilicities and carbon basicities despite widely differing Brønsted basicities. For that reason, these reactivity parameters are suggested as guidelines for the development of novel organocatalysts. The Marcus equation is employed for the determination of the intrinsic barriers of these reactions. Geschwindigkeits- und Gleichgewichtskonstanten der Reaktionen von Pyridinen mit Donor-substituierten Benzhydrylium-Ionen wurden spektralphotometrisch bestimmt. Die Korrelationsgleichung log,k(20,°C)=s(N+E), die mit s und N Nucleophil-spezifische und mit E einen Elektrophil-spezifischen Parameter enthält, wurde verwendet, um die Nucleophilie-Parameter von verschiedenen Pyridinen in CH2Cl2 und in wässrigen Lösungen zu bestimmen und um diese mit N anderer Nucleophile zu vergleichen. Es wurde gefunden, dass der nucleophile Organokatalysator 4-(Dimethylamino)pyridin (DMAP) und tertiäre Phosphane vergleichbare Nucleophilien und Kohlenstoffbasizitäten haben, obwohl ihre Brønsted-Basizitäten sehr unterschiedlich sind. Daher wird vorgeschlagen, die Reaktivitätsparameter als Richtgrößen zur Entwicklung neuer Organokatalysatoren heranzuziehen. Die Marcus-Gleichung wird eingesetzt, um die intrinsischen Barrieren dieser Reaktionen zu bestimmen. [source]

The DMAP-Catalyzed Acetylation of Alcohols,A Mechanistic Study (DMAP=4-(Dimethylamino)pyridine)

CHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2005
Shangjie Xu Dr.
Abstract The acetylation of tert -butanol with acetic anhydride catalyzed by 4-(dimethylamino)pyridine (DMAP) has been studied at the Becke3,LYP/6-311+G(d,p)//Becke3,LYP/6-31G(d) level of theory. Solvent effects have been estimated through single-point calculations with the PCM/UAHF solvation model. The energetically most favorable pathway proceeds through nucleophilic attack of DMAP at the anhydride carbonyl group and subsequent formation of the corresponding acetylpyridinium/acetate ion pair. Reaction of this ion pair with the alcohol substrate yields the final product, tert -butylacetate. The competing base-catalyzed reaction pathway can either proceed in a concerted or in a stepwise manner. In both cases the reaction barrier far exceeds that of the nucleophilic catalysis mechanism. The reaction mechanism has also been studied experimentally in dichloromethane through analysis of the reaction kinetics for the acetylation of cyclohexanol with acetic anhydride, in the presence of DMAP as catalyst and triethylamine as the auxiliary base. The reaction is found to be first-order with respect to acetic anhydride, cyclohexanol, and DMAP, and zero-order with respect to triethyl amine. Both the theoretical as well as the experimental studies strongly support the nucleophilic catalysis pathway. [source]

Ultrafast Relaxation Dynamics of the Excited States of 1-Amino- and 1-(N,N -Dimethylamino)-fluoren-9-ones

CHEMPHYSCHEM, Issue 17 2009
Mahendra Varne
Abstract The dynamics of the excited states of 1-aminofluoren-9-one (1AF) and 1-(N,N -dimethylamino)-fluoren-9-one (1DMAF) are investigated by using steady-state absorption and fluorescence as well as subpicosecond time-resolved absorption spectroscopic techniques. Following photoexcitation of 1AF, which exists in the intramolecular hydrogen-bonded form in aprotic solvents, the excited-state intramolecular proton-transfer reaction is the only relaxation process observed in the excited singlet (S1) state. However, in protic solvents, the intramolecular hydrogen bond is disrupted in the excited state and an intermolecular hydrogen bond is formed with the solvent leading to reorganization of the hydrogen-bond network structure of the solvent. The latter takes place in the timescale of the process of solvation dynamics. In the case of 1DMAF, the main relaxation pathway for the locally excited singlet, S1(LE), or S1(ICT) state is the configurational relaxation, via nearly barrierless twisting of the dimethylamino group to form the twisted intramolecular charge-transfer, S1(TICT), state. A crossing between the excited-state and ground-state potential energy curves is responsible for the fast, radiationless deactivation and nonemissive character of the S1(TICT) state in polar solvents, both aprotic and protic. However, in viscous but strong hydrogen-bond-donating solvents, such as ethylene glycol and glycerol, crossing between the potential energy surfaces for the ground electronic state and the hydrogen-bonded complex formed between the S1(TICT) state and the solvent is possibly avoided and the hydrogen-bonded complex is weakly emissive. [source]

Determination of Diclofenac in Urine Samples by Molecularly-Imprinted Solid-Phase Extraction and Adsorptive Differential Pulse Voltammetry

ELECTROANALYSIS, Issue 15 2007
Laura Fernández-Llano
Abstract A molecularly imprinted polymer for diclofenac (DCF) was prepared by thermal polymerization over silica beads using 2-(dimethylamino)ethyl-methacrylate as functional monomer. After silica elimination by HF treatment, the polymer was applied to the selective solid-phase extraction of the drug from urine followed by its quantification by adsorptive differential pulse voltammetry. Results indicate that the drug could be selectively extracted from the sample and quantified at clinically relevant concentrations (,g/mL). [source]

Proteomic analysis of rat brain tissue: Comparison of protocols for two-dimensional gel electrophoresis analysis based on different solubilizing agents

ELECTROPHORESIS, Issue 24 2002
Lucia Carboni
Abstract The present study reports a comparison of recently described solubilizing methods, to set up a simple protocol for obtaining two-dimensional (2-D) gel electrophoresis maps of brain tissue. Different protocols were used for preparing rat brain homogenates and the resulting maps were compared by image analysis. Three different detergents, two delipidation methods, and introduction of a fractionation step based on different protein solubility in surfactants, were evaluated. When using efficient zwitterionic detergents (3-[(3-cholamidopropyl)dimethylamino]-1-propanesulfonate, CHAPS; amidosulfobetaine 14, ASB-14), the patterns obtained by direct loading of total extracts were qualitatively overlapping with patterns obtained from fractionated samples. In contrast, a weaker nonionic agent (Nonidet P-40, NP-40) produced a different protein pattern in the collected fractions. Delipidation did not improve the results for all the different extraction methods. Immunoblots performed with antibodies recognizing cytosolic and membrane-spanning proteins, which were detected as nondegraded spots, showed that membrane proteins with intermediate molecular mass could be recovered. We suggest, as a simple and efficient method for preparing rat brain maps, the homogenization in a solution containing an efficient zwitterionic surfactant, which allows to solubilize cytosolic and membrane proteins in a single step. Alternatively, a fractionation can be carried out on samples homogenized by a weak solubilizing agent, a more labor-intensive effort resulting in a larger number of proteins on two maps. [source]

Metal Effects on the Asymmetric Synthesis of a New Heterobidentate As/P=S Ligand

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2010
Mengtao Ma
Abstract The cycloaddition reaction between 3,4-dimethyl-1-phenylarsole and diphenylvinylphosphane sulfide was promoted by chiral palladium and platinum complexes containingortho -metalated (S)-[1-(dimethylamino)ethyl]naphthalene. They exhibited similar stereoselectivity; the palladium cycloadducts could not be separated via column chromatography and fractional crystallization, however, the corresponding platinum complexes could be successfully converted into their enantiomerically pure counterpart. A formal arsanylidene elimination reaction was observed on the liberated free As/P=S bidentate ligand. [source]

Nucleophilic Addition of Water and Alcohols to Dicyanonitrosomethanide: Ligands with Diverse Bonding Modes in Magnetically Coupled d-Block Complexes

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2010
Anthony S. R. Chesman
Abstract Ligands resulting from the transition-metal-promoted nucleophilic addition of water or an alcohol to dicyanonitrosomethanide ions (dcnm) have been utilised in the formation of a large series of polynuclear complexes. Addition of water to dcnm results in formation of carbamoylcyanonitrosomethanide (ccnm); deprotonation of this ligand gives amidocarbonyl(cyano)nitrosomethanide (acnm), which has been incorporated into the trinuclear complex [Cu3(acnm)2(dmae)2(H2O)2] [dmae = 2-(dimethylamino)ethoxide] (1) which shows strong antiferromagnetic coupling with an exchange coupling constant, J = ,500 cm,1. [Cu(acnm)(NH3)2], (2) marks the first instance of acnm facilitating the formation of a coordination polymer, namely a 1D chain with intramolecular hydrogen bonding. Attempts to synthesise 2 through different reaction conditions instead resulted in the mononuclear [Cu(acnm)(NH3)2(py)] (py = pyridine) (3). The addition of ethanol to dcnm results in cyano[imino(ethoxy)methyl]nitrosomethanide (cenm) which features in the mononuclear [Cu(cenm)2(H2O)2] (4) and polymeric {[Cu(cenm)2]2·H2O}, (5). The latter is the first example of the cenm ligand in a coordination polymer and has a highly unusual coordination mode through the nitrile groups and extremely weak antiferromagnetic coupling. {[Mn3(ccnm)2(EtOH)2(OAc)4]·2EtOH}, (6) and (Et4N)2[Cu(ccnm)4] (7) contain previously unobserved coordination modes of the ccnm ligand while the complex [Mn(cmnm)3Mn(bipy)(MeOH)](ClO4) (8) {cmnm = cyano[imino(methoxy)methyl]nitrosomethanide, bipy = 2,2,-bipyridine} displays weak antiferromagnetic coupling between manganese atoms with J = ,1.44 cm,1. A change in the solvent systems used in the synthesis of 7 results in the formation of the mononuclear complexes [Mn(bipy)2(dcnm)2] (9) or [Mn(bipy)2(H2O)(dcnm)](dcnm)·H2O (10) and [Mn(bipy)2(dcnm)(H2O)](dcnm) (11). The addition of ethlyene glycol monomethyl ether to dcnm gives cyano[imino(2-methoxyethoxy)methyl]nitrosomethanide (cgnm) and the formation of [Cu(cgnm)2(H2O)2] (12). [source]

Novel Enantioselective Synthesis of Functionalized Pyridylarsanes by a Chiral Palladium Template Promoted Asymmetric Hydroarsanation Reaction

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 27 2009
Fengli Liu
Abstract The asymmetric hydroarsanation reactions between diphenylarsane and (E)-1-phenyl-3-(pyridin-2-yl)-2-propenone and (E)-1-methyl-3-(pyridin-2-yl)-2-propenoate have been achieved by use of the organopalladium complex containing ortho -metalated (R)-[1-(dimethylamino)ethyl]naphthalene as the chiral reaction template in high regio- and stereoselectivities under mild conditions. Hydroarsanation of (E)-1-phenyl-3-(pyridin-2-yl)-2-propenone with diphenylarsane generated two stereoisomeric products in the ratio of 3:1 as five-membered As,N bidentate chelates on the chiral naphthylamine palladium template. Using the same chiral metal template, the corresponding hydroarsanation reaction with (E)-1-methyl-3-(pyridin-2-yl)-2-propenoate gave only one product as a six-membered As,N bidentate chelate. The naphthylamine auxiliary could be removed chemoselectively by treatment with concentrated hydrochloric acid to form the corresponding optically pure neutral complexes. Subsequent ligands displacement from the palladium using aqueous potassium cyanide generated the optically pure keto- and ester-functionalized chiral pyridylarsane ligands. The absolute configuration and the coordination properties of the pyridylarsanes have been established by single-crystal X-ray analysis.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

One-Dimensional Coordination Polymers of MnII, CuII, and ZnII Supported by Carboxylate-Appended (2-Pyridyl)alkylamine Ligands , Structure and Magnetism

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2009
Himanshu Arora
Abstract Four new complexes [MnII(L1OO)(H2O)][ClO4]·2H2O (1), [ZnII(L1OO)][ClO4]·2H2O (2), [CuII(L3OO)][CF3SO3]·H2O (3), and [ZnII(L3OO)][ClO4] (4) (L1OO, = 3-[(2-(pyridine-2-yl)ethyl){2-(pyridine-2-yl)methyl}amino]propionate; L3OO, = 3-[(2-(pyridine-2-yl)ethyl){(dimethylamino)ethyl}amino]propionate) have been synthesized and characterized by elemental analysis, IR, and UV/Vis spectroscopy. Structural analysis revealed that 1, 3, and 4 are one-dimensional chain-like coordination polymers. In 1 distorted octahedral MnN3O3 and in 3 square-pyramidal CuN3O2 coordination is satisfied by three nitrogen atoms and an appended carboxylate oxygen atom of the ligand, and an oxygen atom belonging to the carboxylate group of an adjacent molecule. In 4 trigonal bipyramidal ZnN3O2 coordination environment is provided by two nitrogen atoms and an appended carboxylate oxygen atom of the ligand in the equatorial plane, and the two axial positions are satisfied by a tertiary amine nitrogen and an oxygen atom belonging to the carboxylate group of an adjacent molecule. In 1 the MnII center is coordinated by an additional water molecule. In these complexes each monomeric unit is sequentially connected by syn - anti carboxylate bridges. Temperature-dependent magnetic susceptibilities for 1 and 3 are measured, revealing antiferromagnetic interactions through syn - anti carboxylate bridges between the MII centers. Analysis of the crystal packing diagram reveals that in 1 extensive ,,, stacking involving alternate pyridine rings of adjacent 1D chain exists, which eventually lead to the formation of a 2D network structure. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

quart -Feproline: Synthesis of a Very Rigid [3]Ferrocenophane-Derived Artificial Amino Acid

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2008
Ludger Tebben
Abstract Starting from the ,-(dimethylamino)[3]ferrocenophane derivative 1, a short reaction sequence was developed to form a doubly anellated dihydropyrrole derivative 6 containing the ferrocenophane framework. Intermediate 6 was used for the synthesis of the (R,S,pS)-enantiomer of the rigid artificial amino acid "quart -Feproline". (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Electronic Control of the Rotational Barrier in ,2 -Alkyne-1-thio Complexes

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2007
Wolfram W. Seidel
Abstract A family of thio-alkyne complexes [Tp,Mo(CO)(L)(BnSC2S)] {Bn = benzyl, Tp, = hydrotris(3,5-dimethylpyrazolyl)borate, L = carbonyl (2), 2,6-dimethylphenyl isocyanide (7), tert -butyl isocyanide (8), 4-(dimethylamino)pyridine (9)} was prepared by reductive removal of a benzyl group in the corresponding bis(benzylthio)acetylene complexes [Tp,Mo(CO)(L)(BnSC2SBn)](PF6) (1 -PF6, 4 -PF6, 5 -PF6 and 6 -PF6). All complexes were characterized by IR, 1H, 13C spectroscopy and cyclic voltammetry. X-ray diffraction studies of 5 -PF6, 8 and 9 were carried out. The alkyne ligand is bound symmetrically to molybdenum in 5 -PF6 and unsymmetrically in 8 and 9. The trend in the ,-acidity of ligand L is reflected in the spectroscopic and electrochemical data as well as in the molecular structures. Variable temperature 1H NMR investigations with 7, 8 and 9 disclosed that the barrier of the alkyne rotation at molybdenum decreases in the order of rising electron density at the metal center while the steric demand increases. Therefore, electronic control of the barrier by the specific character of the ligand L is evident.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Two- and Three-Dimensional Hydrogen-Bonded Networks Built from 1,3,5-[(HO)2(O)P]3C6H3 and 4-(Dimethylamino)pyridine

Extended X-ray Absorption Fine Structure Study of Copper(I) and Copper(II) Complexes in Atom Transfer Radical Polymerization

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2003
Tomislav Pintauer
Abstract Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy has been used to investigate structural features of CuIBr and CuIIBr2 complexes with dNbpy, PMDETA, Me6TREN, tNtpy, and Me4CYCLAM in various solvents {dNbpy = 4,4,-bis(5-nonyl)-2,2,-bipyridine, PMDETA = N,N,N,,N,,,N,, -pentamethyldiethylenetriamine, Me6TREN = tris[2-(dimethylamino)ethyl]amine, tNtpy = 4,4,,4,,-tris(5-nonyl)-2,2,:6,,2,,-terpyridine, Me4CYCLAM = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane}. The structures of the CuI and CuII complexes were found to depend on the solvent polarity and the number of nitrogen atoms in the ligand. Generally, in non-polar media and with monomers typically used in ATRP, CuI complexes preferred a tetracoordinate geometry, and were either ionic as observed in [CuI(dNbpy)2]+[CuIBr2], (CuI,NAV = 2.00 Å, CuI,BrAV = 2.25 Å) and [CuI(Me4CYCLAM)]+[CuIBr2], (CuI,NAV = 2.06 Å, CuI,BrAV = 2.23 Å), or neutral as in [CuI(PMDETA)Br] (CuI,NAV = 2.12 Å, CuI,BrAV = 2.33 Å), and [CuI(tNtpy)Br] (CuI,NAV = 2.03 Å, CuI,BrAV = 2.29 Å). The EXAFS analysis of CuIIBr2 complexes indicated a preference for a coordination number of five, such as in [CuII(dNbpy)2Br]+[Br], (CuII,NAV = 2.03 Å, CuII,BrAV = 2.43 Å), [CuII(PMDETA)Br2] (CuII,NAV = 2.03 Å, CuII,Br1,AV = 2.44 Å, CuII,Br2,AV = 2.64 Å) and [CuII(Me6TREN)Br]+[Br], (CuII,NAV = 2.09 Å, CuII -BrAV = 2.39 Å), with the exception of the neutral tetracoordinate [CuII(dNbpy)Br2] (CuII,NAV = 2.02 Å, CuII,BrAV = 2.36 Å), which has been observed in non-polar media. Additionally, polar media were found to favor bromide dissociation in [CuII(Me6TREN)Br]+[Br], and [CuII(PMDETA)Br2], as indicated by a decrease in the Br and Cu coordination numbers at the Cu- and Br- K -edges, respectively. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

Synthesis and Dynamic Features of (Chloro)zirconocene Cations Stabilised by Pendant (Diarylphosphanyl)alkyl and (Dimethylamino)alkyl Substituents at Their Cyclopentadienyl Ring Systems

Polycationic States of Oligoanilines Based on Wurster's Blue

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 26 2009
Akihiro Ito
Abstract Polycations of two oligoanilines based on Wurster's blue,N,N,,N, -tris[4-(dimethylamino)phenyl]- N,N,,N, -trimethyl-1,3,5-benzenetriamine (2) and N,N, -bis(3-{N -[4-(dimethylamino)phenyl]- N -methylamino}phenyl)- N,N, -dimethyl- p -phenylenediamine (3), have been generated efficiently by a stepwise oxidation procedure. Their redox behavior was characterized in terms of the embedded p -phenylenediamine (PD) units and their intramolecular connectivity. EPR analysis of the oxidized 2 and 3 species revealed the existence of high-spin species in solution. It was found that spin multiplicities of the dominant polycationic species of 2 and 3 formed by 3 equiv. of oxidant can be assigned to quartet and doublet states, respectively on the basis of pulsed EPR spectroscopy. These results demonstrate that the intramolecular connectivity between the spin-containing units decisively influences the spin preference of the multispin systems based on oligoanilines.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]