ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P157. Mo and W Complexes of Pyrane Dithiolene Derivatives as Synthetic
Analogues of the Cofactors in Oxotransferases
P. S. Prinson, C. Schulzke
Institute for Inorganic Chemistry, Georg-August-University of Goettingen, Tammanstrasse 4., 37077,
Goettingen, Germany,
e-mail: Prinson.Samuel@ chemie.uni-goettingen.de
Dithiolene complexes of Mo and W have been well documented since early 1960s, but the role of this chemistry
in biology was revealed only after the structure of molybdopterin, a dithiolene ligand coordinated to the Mo
centres in the cofactors of oxotransferases, was proposed by Rajagopalan in 1982 [1, 2]. Since this time,
considerable efforts have been made by the inorganic chemists to synthesize the dithiolene complexes of Mo and
W as the structural analogues of these cofactors [3]. But adequate analogues in terms of the chemical structure of
the dithiolene ligands are rare in the literature either due to the difficulty to prepare or due to the overwhelming
tendency to achieve the analogous metal centers using conventional type ligands. Our approach to this problem
utilizes dithiolene ligands of derivatives of pyrane which is already present in the molybdopterin structure. Our
present study involves the preparation of Monooxobis(chromanedithiolene) Mo(IV) complexes as well as its
W(IV)analogue (Fig.). In addition to the basic characterizations, cyclic voltametry or differential pulse
voltametry of the complexes have been carried out to investigate the response of the redox potentials to
temperature and the nature of the substituents in the dithiolene ligand. The results have been compared with
dithiolene complexes with non-pyrane substituents [4]. Finally, the catalytic activities of the new complexes
have been explored in the model oxotransfer reaction between PPh3 and DMSO.
References:
[1]. Johnson J.L., Rajagopalan K.V., Proc. Natl. Acad. Sci. USA, 1982, 79, 6856.
[2]. Rajagopalan K.V., Adv.Enzymol. Relat. Areas. Mol. Biol., 1991, 64, 215.
[3]. Enemark J.H., Cooney J.A., Wang J.J., Holm R.H., Chem. Rev., 2004, 104, 1175.
[4]. Schulzke C., Dalton. Trans., 2005, 713.
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