Search results for " Spectroscopy"

- conformational preference of , -9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid

1985

Abstract The 1 H and 13 C nmr spectra of exo , exo -9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid, 3, in DMSO-d 6 or alkaline D 2 O, clearly show that it exists in a boat - chair -conformation with equatorial carboxyl groups, thus being the first case of boat - chair preference of a bicyclo[3.3.1] nonan-9-one due to the presence of exo , exo -2,4- substituents.

Synthesis of peptides with α,β‐dehydroamino acids, III. Debenzyloxycarbonylation and detrifluoroacetylation of dehydroalanine and dehydrophenylalanin…

1985

The removal of amino protecting groups from a series of twelve model Z-3) or TFA-dipeptides of dehydroalanine and (Z)-dehydrophenylalanine was investigated. During this deprotection, peptides with Δ Ala are prone to side reactions to a higher extent than those with Δ Phe. Therefore it is interesting to note that from the Δ Ala peptides, the Z group can be split off in preparative manner with HCO2NH4 in the presence of Pd C (Table 4). Synthese von Peptiden mit α,β-Dehydroaminosauren, III.– Debenzyloxycarbonylierung und Detrifluoracetylierung von Dehydroalanin- und Dehydrophenylalanin-Peptiden An einer Serie von zwolf Z-3) oder TFA-Modellpeptiden mit Dehydroalanin und (Z)-Dehydrophenylalanin …

Photoelectrical properties of indandione fragment containing azobenzene compounds

2014

Organic materials are becoming more popular due to their potential application in electronics. Low molecular weight materials possible produce from solution are in special consideration. It gives the possibility to avoid both thermal evaporation in vacuum, and use of polymers in thin film preparation process. Indandione fragment containing azobenzene compounds are one of such materials. These compounds are good candidates for use in design of novel molecular electronic devices due to their possibility to form amorphous structure from solution thus allowing developing flexible, small size systems with low production costs. In this work three indandione fragment containing azobenzene compound…

UV-photometrische analyse kationisch erzeugter polystyrole, 1. Nachweis des covalenten einbaus von acylresten aus aromatischen acylperchloraten

1983

Polymerization of styrene was found not to take place with 4-phenylazobenzoyl perchlorate in benzene solution. 4-Biphenylcarbonyl perchlorate, however, initiates styrene polymerization under the same conditions leading to a product not containing acyl groups as indicated by UV spectroscopic analysis. 4-Phenylazobenzoyl, 2-naphthoyl, and 9,10-dioxo-2-anthracenecarbonyl perchlorate (6b, 7b, and 8b), prepared form silver perchlorate and the corresponding acyl chlorides 6a, 7a, and 8a in styrene, were found to initiate the polymerization of styrene under anhydrous conditions at −25°C in the dark. By UV spectroscopy it could be shown that the resulting polymers contain covalently bound acyl grou…

1992

A series of copolymers are synthesized by repetitive Diels-Alder polyaddition reaction of bifunctional cyclohepta-1,3,5-trienes with bifunctional 1,2,4-triazoline-3,5-diones. The copolymers of different bistriazolinediones with a bisdiene, or of different biscycloheptatrienes with a dienophile, have good solubility in CH2Cl2 and CHCl3, while the homopolymers are poorly soluble. The copolymers were characterized by standard analytical techniques to test the structural regularity of these systems. Due to the kinetic control, it is possible to apply copolymerization statistics to these systems. Based on a model study, it is concluded that alipatic and aromatic bistriazolinediones have the same…

Cyclopolymerisation einiger glutardialdehyde. Struktur der polymeren

1962

Die loslichen Spontanpolymerisate des Glutardialdehyds, β-Methyl- und β-Phenylglutardialdehyds bestehen auf Grund ihrer Eigenschaften und IR-Spektren vornehmlich aus Tetrahydropyranstruktureinheiten, die durch eine Cyclopolymerisation gebildet werden. Es wird ein infrarotspektroskopischer Vergleich mit verschiedenen niedermolekularen Tetrahydropyran-Modellsubstanzen durchgefuhrt. Die unkatalysierte Polymerisation last sich infrarotspektroskopisch verfolgen. Die Poly-glutardialdehyde konnen acetyliert werden. Die Polymeren erfahren durch die Acetylierung eine wesentliche thermische Stabilisierung. Die Eigenschaften und IR-Spektren der Spontanpolymerisate werden mit denen des vernetzten Poly-…

<strong>Synthesis and Platinum (II) Complexes of Different Polyazacyclophane Receptors</strong>

2015

During the last years, research on coordination chemistry of platinum has aroused great interest due to their potential biological applications. Herein, we report the interaction of PtCI42- with different polyazacyclophanes containing a pyridine unit as aromatic spacer. Formation of complexes has been studied by 1H and 195Pt NMR spectroscopy. Analysis of the recorded spectra of D2O solutions containing L and PtCl42- in a 1:1 molar ratio at acidic pH shows the evolution with time of the 1H and 195Pt signals. Different crystal structures have been solved by X-ray diffraction analysis. At acidic pHs, the metal ion is coordinated by the central amino group of the macrocyclic cavity and three ch…

Spectroscopic behaviour of metal–drug complexes. Infrared spectra of Cu(II) complexes with 5-amino-1,3,4-thiadiazole-2-thiol (Hatm)

1997

Abstract The infrared spectra of the drug Hatm and its copper (II) complexes with stoichiometry [Cu(atm) 2 (H 2 O)] and [Cu(Hatm)(HIm) 2 (SO 4 )] are reported and discussed. The Raman spectrum of Hatm is also reported. An assignment of Hatm, HIm, H 2 O and SO 4 modes in the complexes is proposed in comparison with the modes of the free ligands. Important information about the metal–ligand vibrations has been obtained.

Tin(IV), Monomethyltin(IV), and Dimethyltin(IV) Complexes with thiol sulfur and heterocyclic nitrogen donors: Molecular dynamics and structure by119S…

1995

The molecular dynamics of the complexes Sn(SPyN)4 (1), SnCl2(SPyN)2 (2), MeSn(SPy)3 (3), MeSnCl(SPyN)2 (4), Me2Sn(TCy)2 (5), Me2SnCl(TOx) (6), and Me2Sn(TUr) (7) [HSPy = 2-mercaptopyridine; HSPyN = 2-mercaptopyrimidine; HTCy = 2-thiocytosine; HTOx = 8-thioquinoline; H2TUr = 2-thiouracil] has been investigated by variable temperature 119Sn Mossbauer spectroscopy. The area under the resonant peaks has been determined as function of temperature, from which Debye temperatures and cut-off frequencies, as well as recoil-free fractions (Lamb Mossbauer factor) and mean square displacements of 119Sn, have been calculated. By fingerprint procedures on the basis of literature data, monomeric structure…

Conformational studies of hexapeptides containing two dehydroamino acid residues in positions 3 and 5 in peptide chain

2008

Abstract Synthesis and structural studies of hexapeptides containing two dehydroamino acid residues in positions 3 and 5 in a peptide chain were performed. All the investigated peptides adopted bent conformations, stabilized by intramolecular hydrogen bonding, and could exist as two different conformers in solution. Only in the case of the peptide containing ΔAla residues, expected 3 10 -helical conformation was found.