Nickel pyrimidine complexes

Elmoghayar MRH, Undheim K (1983) Nickel-complex catalysis in the reaction between Grignard reagents and substituted pyrimidines. Acta Chem Scand B 37 160-162... 

A H and P n.m.r. study of thiamine pyrophosphate in the presence of cobalt(ii) or nickel(ii) indicate that the TPP is bonded to the metal via pyrophosphate and the pyrimidine group, in a similar manner to ATP-M complexes. 

Complexes of thieno[2,3-d]pyrimidines 100 (R1 = NH2 R2 = NHEt, NEt2, NEtPh, or morpholino R3 = C02Me) with copper(II), nickel(II), and cobalt(II) have been obtained. The metals were found to coordinate with N-l of the thieno[2,3-d]pyrimidines (88MI2 94MI4). 

Figure 3.21 Complexes of nickel(ll), palladium(ll) andplatinum(ll) with pyrimidine functionalised carbene ligands.

Substances showing catalytic waves in ammoniacal cobalt or nickel solutions< > must fulfil another condition beside the two conditions mentioned above the substance has to form a complex-compound with cobalt and other components of the solution. Moreover, the acid properties of this complex and its adsorbability also seem to be of importance. The substances showing a catalytic effect of this type usually contain at least an atom of sulphur in their molecule (e.g. cysteine, dithiopyrimidine or proteins). Whether or not the presence of sulphur in the catalytically active molecule is a sufficient condition has yet to be decided. It was shown that e.g. gelatin or casein containing little or no sulphur atoms do not produce any catalytic wave of this type. Similarly, in the series of hydantoin, thiohydantoin and dithiohydantoin as well as pyrimidine, thiopyrimidine, and dithiopyrimidine, the catalytic effect was only observed for the thioderivative and it increased with the number of sulphur atoms in the molecule. 

Steffen A, Sladek MI, Braun T, Neumann B, Stammler HG (2005) Catalytic C-C coupling reactions at nickel by C-F activation of a pyrimidine in the presence of a C-Q bond the crucial role of highly reactive fluoro complexes. OrganometaUics 24 4057-4064... 

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