Proposed molecular structure

High Dehydration Temperature - In contrast to other forms of zinc borates, the water of hydration of the zinc borate is retained up to 290°C, thus allowing it to be used in polymers requiring high processing temperatures. The proposed molecular structure for the zinc borate is depicted in Fig. 

Crosscheck proposed molecular structure and mass spectral data. This is also recommended between the single steps of mass spectral interpretation. 

The above results are summarized in a proposed molecular structure and proposed description for the origin of thermal decomposition products. The purpose of presenting molecular structures is to summarize research results in a concise form which will allow a convenient comparison to other work. For example, the proposed structure is similar to those of Wiser (6) and of Heredy and Wender ( 7). But these structures only represent aspects of the structure which are constrained by available data, and are not unique. They may be wrong in details for which data is missing. Care should therefore be exercised in the way such models are interpreted. 

It is thus apparent that there is considerable evidence pointing to the presence in native purified cellulosic materials of acidic groups which must be considered an integral part of the basic structure. Any proposed molecular structure of cellulose which fails to account for the presence of carboxyl groups must therefore be regarded as inadequate. 

Investigations with solid state NMR, IR, and Raman spectroscopy confirmed the proposed molecular structures and pointed to the fact that during dehydrocoupling, the cyan amide unit of the starting compound isomerized to carbodi-imide motifs. NMR signals at unexpected low fields (-165 ppm) and IR bands... 

Proposed Molecular Structure of the BPHT CD Inclusion Complexes... 

Frequently, with smaller and well-diffracting structures (W , < 700 and dp > 10), all atoms of the structure can be written out as the initial model by the program and they just have to be named correctly (as in Fig. 9.11) and refined. The refinement process (see Refs. 110 —1121) uses incremental movement of the atom coordinates and atomic displacement parameters (commonly called as thermal parameters ) of the structure solution model using the so-called least-squares method. The model (the calculated structure factors) is fitted against the measured data (the observed structure factors) and the R-factor (see above. Section 9.2.1) is calculated. With larger structures or if the unit cell contains light atom solvent molecules (C, H, O, N atoms only), some atoms, sometimes even 50% of all atoms, cannot be located from the first very crude electron density map (calculated from the ab initio phase set). However, those atoms which are chemically feasible (based on the proposed molecular structure) can be fed into the calculation of the calculated structure factors Peak ( cafc will approach Fobs when a more accurate model is... 

Several reports of organo-gold compounds have been published. In these studies, the main concern was to establish the oxidation state of gold atoms and to deduce whether the XPS data are consistent with the proposed molecular structure. Some of the compounds studied are shown below. 

During the GC/MS screening analyses several still unknown contaminants were detected. Consequently, structure elucidating analyses were performed on two different groups of compounds both appearing in the third extracts. Thus, polar and acidic properties have to be stated for these substances. The identification of the individual compounds was based mainly on the interpretation of their mass spectral properties and subsequent verification of the proposed molecular structures by synthesized reference material. 

Structure 2. Proposed molecular structure of bituminous coal. (Adapted from... 

Structure 3. Proposed molecular structure of bituminous coal containing 82-83% carbon. A star (it) indicates where polymerization might occur. (Adapted... 

Figures Proposed molecular structure of [ (CO)3Fe 2(t -C5H5)CoMe2C2B4H4] (Reproduced from J.C.S. Chem. Comm., 1975, 943)...

Figure 3. Representations of the proposed molecular structure of (GVGVP) (see text for discussion).

The silanediols 15 proved to be stable compounds. Condensation reactions were not observed and are certainly prevented by the bulkiness of the substituents at the silanediol silicon atom. 15a was chosen for an X-ray structure analysis, the results of which confirmed the proposed molecular structure. Bond lengths and angles are in the expected regions (Fig. 1). The crystal structure is characterized by hydrogen bonds (0-0 distances of 2.187 A) which form a dimer of 15a. 

Figure 9 shows proposed molecular structures for the m/z 153 and m/z 169 fragmentation ions. 

Fig. 2 A schematic of the proposed molecular structure of the Na channel present in the heart. This model depicts the transmembrane folding of the primary structure of the Na channel a-subunit. The domains of the channel are indicated as DI-DIV. The six a-helical transmembrane-spanning sequences are indicated as S1-S6 for the DI domain. Some experimentally determined sites for protein kinase A phosphorylation and local anaesthetic binding are shown. Those sequences involved in channel inactivation are also indicated along with those regions that constitute the ion channel pore (P)...

Compoimds are referred to by Roman numeral for proposed molecular structures see pages 196-200. However, VIII is now known to be tt-CsHsCoCsFisO (142a). 

Figure 9.7 Proposed molecular structure for surfactant-like humic material extracted from compost. Adapted from Quagliotto etal. (2006).

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