Donor halogen derivatives

It is important to recognize that the intermolecular long-distance bonding with the participation of halogen derivatives represents a specific example of the broad general area of donor/acceptor interactions. Moreover, the complexes of molecular iodine, bromine and chlorine with aromatic donors represent classic examples of charge-transfer compounds [26-28] that are vital for the development of Mulliken theory of intermolecular association [29-31]. The latter thus provides the convenient framework for the... 

Electronic Spectroscopy and Thermodynamics of Donor/Acceptor Interactions with Halogen Derivatives... 

For the dibridged species, such as the halogen derivatives HOs2(CO)i0X (X = Cl, Br), we have used this type of behavior to explain the stereospecific incorporation of, 3CO into the molecules (160). The halogen group varies from a three-electron donor in bridged molecules to a one-electron donor in the terminally bonded species. 

Homoleptic complexes with bidentate C C donor ylide derivatives are well known. Oxidative addition of some gold(I) [Au2 (CH2)2PR2 2] species by addition of halogen, pseudo-halogen, or alkyl halide affords dinuclear Au(II) complexes which... 

Laser flash photolysis has been performed with the halogenated derivatives in ethanol [374], Measurements of the triplet lifetimes as a function of dye concentration, laser power, and in the presence of electron donors allowed us to determine the rate constants collected in Table 17. 

With benzaldehyde 144 or halogenated derivatives (Cl, F) as acceptors the yeast-PDC-catalyzed addition proceeds with almost complete stereoselectivity to furnish the corresponding (R)-configurated 1-hydroxy-1-phenylpropanones 145 [447]. For practical reasons, whole yeast cells are most often used as the catalyst, with only small loss of enantioselectivity [423,424]. The conversion of benzaldehyde in particular has gained industrial importance because the acyloin is an important precursor for the synthesis of L-(-)-ephedrine [448]. Otherwise, the substrate tolerance is remarkably broad for aromatic aldehydes on the laboratory scale, however, yields of acyloins are usually low because of the prior or consequent reductive metabolism of aldehyde substrate and product, giving rise to considerable quantities of alcohol 146 and vicinol diols 147, respectively [423,424,449], The range of structural variability covers both higher a-oxo-acids (e.g. -butyrate, -valerate) as the donor component, as well as a,/J-un-saturated aldehydes (e.g. cinnamaldehyde 148) as the acceptor [450]. 

The parallel outer-sphere PET mechanism was found in systems containing chromate(VI) plus an electron donor different from alcohol, such as oxalate or phenol and its halogen derivatives [92,95],... 

An apolar aprotic solvent is characterized by a low relative permittivity (sr < 15), a low dipole moment [ju < 8.3 10 Cm = 2.5 D), a low value ca. 0.0... 0.3) cf. Table A-1, Appendix), and the inability to act as a hydrogen-bond donor. Such solvents interact only slightly with the solute since only the non-specific directional, induction, and dispersion forces can operate. To this group belong aliphatic and aromatic hydrocarbons, their halogen derivatives, tertiary amines, and carbon disulfide. 

Names 6, 7, and 8 are concerned with halogen derivatives and compounds in which CO has been displaced by other donor molecules. 

Reductive respiration is associated mostly with halogen derivatives hydrocarbons, which are used as acceptors of electrons. Due to this, the process is also called dehalorespiration or simply halorespiration. Ihe electron donor here is directly dissolved H. Its necessary amount is provided by the fermentation. That is why halorespiration and dechlorination run in two steps (Wiedemeier et al, 1999). Initially H formsin the process of fermentation of non-chlorinated organic compoimds and then it is used as electron donor ... 

I. V. Bulgarovskaya, V. M. Vozzhennikov, R. M. Gitina, D. V. PebaUc, and B. V. Kotov. Photoelectric properties of donor-acceptor polymer compositions of solnble polyimides with poly(A-epoxypropyl)carbazole and its halogenated derivatives. Russ. J. Phys. Chem., 76(2) 291-295, February 2002. 

Weakly dipolar and nonpolar, non-HBD (hydrogen-bond donor) molecules hydrocarbons and halogenated derivatives, ethers, esters, tertiary amines. 

Halogens add to the double bond of the alcohol to afford the corresponding dihalo derivatives, eg, CgH CHXCHXCH20H, where X = Cl or Br. The allyHc chloride C H Cl [2687-12-9] can be obtained by treatment of the alcohol with hydrochloric acid, thionyl chloride, or carbon tetrachloride—triphenylphosphine as the halogen donor. 

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