Synthesis and characterization of cobalamines with anionic and neutral phosphorous donor ligands

Sigrídur Jónsdóttir*, Günter Klar

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


In dimethyl formamide as solvent aquacobalamine reacts with the triorganyl phosphites 3-7 to give the corresponding (diorganylphosphito-P)cobalamines, their new β-axial ligands [P(O)(OR)2]- (3a-7a) being formed by partial hydrolysis. In methanol, however, additional methanolysis normally leads to (dimethylphosphito-P)cobalamine with the axial ligand [P(O)-(OMe)2]- (2a). Exceptions are P(OCH2CH2NMe2)3 (4) giving a complex with the only partially methanolized chiral ligand [P(O)(OCH2CH2NMe2)- (OMe)]- (4b), too, and the bicyclic phosphite 5 which is also coordinated in the unchanged, nonhydrolyzed form. All complexes are characterized by elementary analysis, electrophoresis, UVVis and 1H, 31P NMR spectra. The chirality of the cobalamine moiety causes diatropism of the two organyl groups in the prochiral ligands [P(O)(OR)2]- which is well seen in the NMR spectra of the complexes with the methyl and phenyl derivatives 2a and 6a, whereas the spectra with ligands 3a and (in part) 4a are not resolved well enough to distinguish the two forms. With the chiral ligand 4b two diastereomers are obtained in different yields; this asymmetric induction is indicated by the intensities of the respective signals in the NMR spectra.

Original languageEnglish
Pages (from-to)27-32
Number of pages6
JournalInorganica Chimica Acta
Issue number1
Publication statusPublished - 3 Apr 1989


Dive into the research topics of 'Synthesis and characterization of cobalamines with anionic and neutral phosphorous donor ligands'. Together they form a unique fingerprint.

Cite this