Chlorocarbenes, chlorination

The osmium carbyne complex 115 reacts with elemental sulfur, selenium, and tellurium to afford the complexes 135 in which the element atoms "bridge the metal-carbon triple bond [Eq. (123)] (56). Complex 115 also reacts with transition metal Lewis acids such as AgCl or Cul to give dinuclear compounds with bridging carbyne ligands. Reaction with elemental chlorine results in addition across the metal-carbon triple bond to generate the chlorocarbene osmium complex 136 [Eq. (124)]. 

The condensation of a carbene with a P=C triple bond theoretically affords a 2//-phosphirene. This was indeed shown to be the case by Regitz and co-workers in the synthesis of the only characterized 2//-phosphirene (4) (Scheme 26) <87AG(E)1257>. Some time later, Regitz showed that the use of a chlorocarbene precursor leads to the formation of 1-chlorophosphirenes via a formal [1,3] shift of chlorine in the initial 2//-phosphirenes (Equation (67)) <89AG(E)225,91CB1207). Chloro-diazirines can be replaced by 1,2-dichlorocyclopropenes <91SL433> in this kind of chemistry (Equation (68)). Finally, phosphaalkynes too can be replaced by silylated chlorophosphaalkenes (Scheme 27) <89TL3951>. 

Carbon-13 NMR is being used to characterize the microstructure of a variety of chlorine-containing polymers. Among these are homopolymers, copolymers, and chemically modified polymers. In the last category is the series of polymers obtained by addition of di-chlorocarbene to the double bonds of polybutadiene. 

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