Analysis and Structural Investigation

From among the different classes of compounds considered in this work, most of the computational work was done on amines, while less examples are found for nitro compounds and very few for nitroso ones. The different studies may be classified into several major areas (1) conformational analysis and structural investigation (2) spectroscopic experiments and study of chemical effects (3) investigation of chemical reactions mechanism (4) heats of formation and density calculations, especially of high energetic materials. In the following sections we will concentrate on molecular mechanics based research studies, or on such where molecular mechanics calculations played a... 

BGMN BGMN a new fundamental parameters based Rietveld program for laboratory X ray sources, its use in quantitative analysis and structure investigations, J. Bergmann, P. Friedel and R. Kleeberg, Int. Union Crystallogr., Commission Powder Dijfr. Newsletter 1998, No. 20, pp. 5 8... 

Chemical Analysis and Structural Investigation of Crosslinked Polyesters... 

According to Hiiekel s rule, turcasarin should not be aromatic, but even if the macrocycle should fulfill the (4n +2) rule for aromatic systems the lack of planarity due to the loop conformation would prevent aromatic stabilization. In fact, the existence of the loop conformation in which the whole macrocycle is twisted was demonstrated by X-ray structure analysis and NMR investigations. 

In principle, structure analysis can be considered as distribution analysis in atomic dimensions. However, from the practical point of view it makes sense to deal separately with structure analysis and to differentiate between molecular structure analysis and crystal structure analysis. Further structure investigations concern near-orders in solids and liquids (e.g. glass). 

C4-position of the starting (3-lactam in diastereomeric ratios of about 85 15 (Scheme 4). Pure optically active compounds could be obtained in almost all cases after chromatography. Unambiguous structure elucidation could be achieved by X-ray crystal analysis and NOE investigations. 

An interesting synthetic and structural investigation deals with the chiral configuration of cyclotriphosphazenes carrying macrocyclic substituents. Two configurations of compound (83) could be isolated from a reaction mixture of (82) and piperazine, viz. a meso- and racemate-form as proven by X-ray analysis. Further aminolysis yielded two meso-forms of (84), one with a plane of symmetry, the other with a center of symmetry. The results are consistent with inversion of configuration at a P(OR)Cl center for each substitution step going from (82) to (84). The patterns of the P NMR spectra are consistent with the X-ray structures. ... 

The range of pyrolysis products is a function of the composition and structure of the pyrolysed sample, which accounts for the applicability of Py—GC in quantitative analysis and structural studies. Determining the composition of polymer systems (mixtures and copolymers) and establishing the structure of the analysed polymers are practically important and complex problems. Py—GC is used successfully in solving these problems and is one of the few methods that can be employed in investigating insoluble polymers. 

Organometallic and Coordination Compounds. - Crystallization of ferrocene and ruthenocene substituted in the 1- and T-positions by two nitronyl nitroxide radicals gave the new crystal phases p-1 (besides the known phase a-1, a-2, and a-2 whose structures were determined by X-ray analysis and were investigated by C and H NMR spectroscopy with MAS NMR. The solid state Sn CP MAS NMR spectra of a series of triaryltin chlorides of the form ArsSnCl have been acquired. The indirect spin-spin coupling constants (J( Sn- C1)), quadrupolar-dipolar shifts (6( Sn- Cl)), and the Sn chemical shift tensors were extracted. " Powders of the zinc and copper(II) dimethyl-(MDtc), diethyl-(EDtc), and morpholinedithiocarbamate (MfDtc) complexes quantitatively absorb hexamethyleneimine (Hmi) to produce the adducts... 

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