Boronic halogen-substituted

The most widely used method for the synthesis of iminoboranes involves the 1,2-addition of boron-element bonds such as boron-hydrogen, boron-halogen, boron-carbon, or boron-sulfur bonds across the C=N bond of nitriles thereby producing variously substituted iminoboranes (Eq. (2)). The formation of iminoboranes as well as the stability of the products depends on the substituent on the nitrile group, the nature of the boron-element bond to be cleaved during the 1,2-addition across the C N bond, and to a lesser extent on the non-reacting boron substituents 26T... 

In systems derived from PH3 BH3, changes in the coupling constant, /pH, are found which are similar to those seen in compounds derived from PH3, i.e. compounds with phosphorus in coordination number 3. The observation that the alteration does not correspond to that seen for derivatives of PHi suggests that the very weak donor-acceptor bond in PH3 BH3 does not affect the hybridisation of phosphorus, as compared with that in free PH3, as much as might at first be expected. A small increase in the electron withdrawing action by halogen substitution of the hydrogen atoms bonded to boron causes an increase in the s character of the P-H bonds. 

Li, L.-F. and You, X.-Z. (1993a). A Topological Index and Its Application. Part 3. Estimations of the Enthalpies of Formation of Mixed Halogen-Substituted Methanes, Silanes and Boron Mixed Halides. Thermochim.Acta, 225,85-96. 

Halogen-substituted boronate derivatives and the electron capture detector... 

The subphthalocyanines (SubPes the trimeric homologues of tetrameric Pcs) have been prepared in the presence of boron(III) as template. No other metal ions controlling the formation of SubPc have been found so far. Originally, the unsubstituted SubPes would have been synthesised by the reaction of phthalonitrile with BF3 or BCI3 at 240°C in 1-chloronaphthalene as solvent in 20-40% yield (Eq. 2.248) [492]. The products are normally contaminated by halogen-substituted subphthalocyanines and their separation is tedious. The structure of the chloro derivative is available [493]. 

The sulfur derivatives are listed after the corresponding oxygen ones, the phosphorus, after the nitrogen ones, the silicon and boron after the carbon ones. In each group, the derivatives produced by halogen substitution are placed at the end of the respective group for ex., ethylenchlorhydrin comes at the end of the alcohol group. 

Halogen bonded to boron or carbon of the CNB grouping of the molecule seems to be of similar activity. Reactions of monomeric iminoboranes with organothiols lead to C-S substituted iminoboranes which will be discussed later (c.f. Sect. VI). 

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