CoCl2/bipy

This polymeric complex then undergoes an intramolecular rearrangement resulting in conversion to the monomeric compound, [CoCl2(bipy)l, with a tetrahedral structure. 

CoCl2(phen)2iCl + en EtOH, r.t. K3fCo(OjC202),] + bipy EtOH, H20, heat Nal... 

Distorted octahedral m-[CoX2(N—N)] complexes are well known,291 and a crystal structure for X = NCS- is available (Table 22). Very distorted five-coordinate [CoX2(terpy)] (X = Cl-, NCO ) is also known (Table 22). Akabori reports that pyrolysis of (HN—NH)CoCl4 salts (N—N = phen, bipy) results in two phases of [CoCl2(N—N)], one of which is polymeric and octahedral and the other is tetrahedral and monomeric,293 but such studies need structural clarification. 

CoClj OHjO + bipy EtOH, heat CoCl2 6H20 + phen EtOH Na3[Co(C03)3l-3H20 + bipy HjO. 8h, NaCt04 to hot soln. 

Preparations of [CoCl2(N—N)]C1 species were pioneered by Jaeger and van Dijk (bipy) and Pfeiffer and Werdelmann (phen) many years ago but recent work is due to Ablov and Palade and to Schaffer and coworkers. A wide range of complexes is now available some of which are given in Table 23. It appears that green traK5 -[CoX2 N—N)]" ions (X = Cr, Br ) are unlikely despite many earlier claims,and considerable doubt now exists about ira j-[Co(OH2)(OH)(N—... 

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