Molecular CONGEN

The molecular and crystal stmctures of 2-phenylbenzotellurazole were determined by X-ray (89KGS1690). The dihedral angle between the planes of the five-membered heterocycle and 2-phenyl ring is 31.2°. In contrast to benzoisotel-lurazole, no shortened intermolecular Te- N contacts were found in the crystal stmcture of 2-phenylbenzotellurazole. Consequently, no anomalies in solubility and melting point were revealed for this compound as compared with its sulfur and selenium congeners. 

In another study (Gage and Holm 1976), the influence of molecular structure was studied on the rate of excretion by mice for 14 different congeners. The results were as follows ... 

Figure 12.4 The molecular structure of a taxane [114]. Taxotere is the semi-synthetic congener of Taxol. (Reproduced by permission from Macmillan Publishers Ltd Susan C. Roberts. Production and engineering of terpenoids in plant cell culture. Nature Chemical Biology 3 (7) 387-395. London Nature Publishing Group. 2007 Macmillan)...

Jacobson, K.A. et al. (1995) Molecular probes for muscarinic receptors Functionalized congeners of selective muscarinic antagonists. Life Sci. 56(11/12), 823-830. 

Conversely, Ti-FI catalysts with MAO normally show lower (but still high) ethylene polymerization activities and form higher molecular weight PEs relative to the Zr congeners. The ethylene polymerization activities of Ti-FI catalysts were also... 

We demonstrated that a series of Ti-FI catalysts 40 (Fig. 25) and 44-47 (Fig. 29) possessing a t-Bu, cyclohexyl, i-Pr, Me, and H ortho to the phenoxy-O (thus having various steric environments in close proximity to the active site) all initiate room temperature living ethylene polymerization, though, for the non-fluorinated congeners, the steric bulk of the substituent ortho to the phenoxy-O significantly influences product molecular weight (Table 6) [28, 33]. 

Borlakoglu, J.T., J.P.G. Wilkins, C.H. Walker, and R.R. Dils. 1990. Polychlorinated biphenyls (PCBs) in fisheating seabirds. III. Molecular features and metabolic interpretations of PCB isomers and congeners in adipose tissues. Comp. Biochem. Physiol. 97C 173-177. 

This coupling method is useful for the preparation of interesting new molecular intermediates as well as for the synthesis of FR900482 skeletal congeners (Scheme 2.330)... 

Elucidation of the mechanism of action for virtually all biologically active substances has been a collaborative effort between scientists in a variety of disciplines. In the area of drug research, medicinal chemists have played important roles by providing series of homologs and congeners of prototype compounds. The development of potency series, where the in vivo action can be correlated with in vitro or biochemical effects, has often played a pivotal role in formulating hypotheses about mechanism of drug action at the molecular level. 

Figure 10 shows the molecular structures of both the copper(II) and copper(I) congeners. As seen, the copper(II) complex possesses an octahedral S402 coordination, whereas the copper(I) complex assumes a tetrahedral S4 coordination releasing the bonding with the two oxygen atoms. 

It is, however, useful to note that changing the nature of the single atom interposed between the two ferrocenyls can vary the nature of the corresponding mixed-valent congener. As an example, Figure 18 shows the molecular structure29 and the electrochemical behaviour of diferrocenylphosphine.30... 

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