Search results for "Amide"

Thermal behaviour and electrochemical properties of bis(trifluoromethanesulfonyl)amide and dodecatungstosilicate viologen dimers

2012

We report the synthesis and characterization of dimeric viologen salts (1',1''-(alkane-1,n-diyl)bis(1-ethyl-4,4'-bipyridinium) with n = 4-10) with bis(trifluoromethanesulfonyl)amide (bistriflimide, Tf(2)N(-)) as a counteranion. For n = 4, 5 and 6, and for the nonylviologen cation (1,1'-dinonyl-4,4'-bipyridinium) we also prepared salts with the totally inorganic dodecatungstosilicate anion, SiW(12)O(40)(4-), featuring a poly-charged surface and nanosized dimensions. The materials have been characterized by means of calorimetric techniques, X-ray diffraction and solid state NMR and a comparison is made with analogous monomeric viologen salts exhibiting smectic mesophases. A strong odd-even ef…

The infrared and Raman spectra of solid tridehydropeptides : influence of ΔAla and ΔPhe on the spectral profile

2012

Abstract A series of solid tripeptides Boc-Gly-X-Gly-OMe (X = dehydroalanine (ΔAla), dehydrophenylalanine (ΔPhe)) was investigated by Raman scattering and Fourier transform infrared spectra to examine the conformational marker bands of the unsaturated residue. The observed fundamental modes gave us the opportunity to analyze structural features that change due to the substitution of Ala by ΔAla and due to the different spatial arrangement of ΔPhe ( Z and E isomers). In addition, we showed the alteration of the spectral profile when the large size residue (Phe) is introduced into the backbone of the peptide with ΔPhe (in Boc-Gly-Δ (Z) Phe-Phe-OMe). The frequency ranges of interest included t…

Separation of chelating agents as copper complexes by capillary zone electrophoresis using quaternary ammonium bromides as additives in N-methylforma…

2006

This study presents the use of quaternary ammonium bromides as additives in N-methylformamide (NMF) for the separation and quantification of chelating agents as copper complexes by capillary zone electrophoresis (CZE). The new quaternary ammonium bromides were synthesized in our laboratory and used for the first time for CZE applications performed in NMF media. The methods were developed and optimized for determination of six chelating agents (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), nitrilotriacetic acid (NTA) and trieth…

Squarate and croconate in designing one- and two-dimensional oxamidato-bridged copper(II) complexes: synthesis, crystal structures and magnetic prope…

2001

Abstract The reaction of squarate (C4O42–, dianion of 3,4-dihydroxycyclobut-3-ene-1,2-dione) and croconate (C5O52–, dianion of 4,5-dihydroxycyclopent-4-ene-1,2,3-trione) with the dinuclear 〚Cu2(apox)〛2+ copper(II) complex 〚H2apox = N,N’-bis(3-aminopropyl)oxamide〛 in aqueous solution affords the compounds of formula 〚Cu2(apox)(C4O4)(H2O)2〛n·n H2O (1) and 〚Cu4(apox)2(C5O5)2〛·6 H2O (2). Crystals of 1 are monoclinic, space group C2/c, with a = 12.5527(9), b = 7.4161(6), c = 18.5198(12) A, β = 100.578(6)° and Z = 4. Crystals of 2 are triclinic, space group P 1 with a = 9.732(5), b = 9.795(2), c = 10.285(3) A, α = 84.95(2), β = 77.30(3), γ = 85.61(3)° and Z = 1. The structure of complex 1 consist…

1983

PYROLYSIS-MASS SPECTROMETRY OF TRUXILLIC AND TRUXINIC POLYAMIDES AND RELATED COPOLYAMIDES

1977

1982

The polyamides 3–5 were synthesized from α,ω-diamino-substituted oligo(oxyethylene)s (1) and bis-chlorides of dicarboxylic acids (2). As copolymers with defined sequences they contain up to five oxyethylene units per repeating unit. Hereby properties like solubility, thermal stability and complexing ability towards alkali metal cations are influenced.

Fully interlocked three-dimensional molecular scaffolding: Synthesis, X-ray structure, magnetic and nitrogen sorption study

2012

Abstract The reaction of M(NO3)2·6H2O (M = Co or Ni), N,N-diethyl-ethylenediamine (deen) and sodium dicyanamide (dca) afforded the complex {[M(deen)(μ1,5-dca)2]}n (where for 1, M = Co and for 2, M = Ni). The complexes have been characterized structurally and magnetically. X-ray analysis reveals that the isomorphous complexes 1 and 2 feature similar infinite three-dimensional scaffolding-like structure to generate the fascinating molecular assembly. All the {N(CN)2}− ligands present in the complexes are connected to the symmetry related metal centers in an end-to-end fashion through bent {N(CN)2}− ligands. The zigzag linkage propagates parallel to three crystallographic axes to form a fully …

Asymmetric and Symmetric Dicopper(II) Paddle-Wheel Units with Modified Nucleobases

2015

New copper(II) paddle-wheel complexes with different modified nucleobases and simple molecules in the axial positions have been prepared by direct reactions between copper(II) salts and the corresponding uracil- or thymine-1-acetic acids under inert atmosphere to produce the two homoleptic complexes, [Cu2(μ-OOCCH2-T)4(G)2] and [Cu2(μ-OOCCH2-U)4(G)2], and the heteroleptic one [Cu2(μ-OOCCH2-T)2(μ-OOCCH2-U)2(G)2] (where OOCCH2-T = thymine-1-acetate, OOCCH2-U = uracil-1-acetate, and G = dimethylformamide, water, dimethylacetamide, or dimethyl sulfoxide). Interestingly, the crystal structures of this family of closely related molecules present significant differences in their supramolecular arra…

H2-Antihistaminika, 2. Mitt. Synthese und Pharmakologie α-substituierter Metiamid-Analoga

1978

Es wird die Synthese α-substituierter 5(4)-Methyl-4(5)-[[2-(N′-methyl-thioureido)-athylmercapto]-methyl]-imidazole4 aus α-substituierten 4(5)-Methoxymethyl-5(4)-methyl-imidazolen 2 sowie die H2-antihistaminische Wirksamkeit der dargestellten 4 beschrieben. H2-Antihistaminics, II: Synthesis and Pharmacology of α-Substituted Metiamide Analogues The synthesis of α-substituted 5-methyl-4- {2-[3-(methyl)thioureido]ethylthiomethyl}-1H-imidazoles 4 from α-substituted 4-methoxymethyl-5-methyl-1H-imidazoles 2 is described. The H2-antihistaminic activity of the products is reported.