Author's Final Manuscript
Journal of Inorganic Biochemistry
The preparation and characterization of new model complexes for the molybdenum cofactor are reported. The new models are distinctive for the inclusion of pterin-substituted dithiolene chelates and have the formulation Tp*MoX(pterin-R-dithiolene) (Tp* = tris(3,5,-dimethylpyrazolyl)borate), X= O, S, R= aryl or –C(OH)(CH3)2). Syntheses of Mo(4+) and (5+) complexes of two pterin-dithiolene derivatives as both oxo and sulfido compounds, and improved syntheses for pterinyl alkynes and [Et4N][Tp*MoIV(S)S4] reagents are described. Characterization methods include electrospray ionization mass spectrometry, electrochemistry, infrared spectroscopy, electron paramagnetic resonance and magnetic circular dichroism. Cyclic voltammetry reveals that the Mo(5+/4+) reduction potential is intermediate between that for dithiolene with electron-withdrawing substituents and simple dithiolate chelates. Electron paramagnetic resonance and magnetic circular dichroism of Mo(5+) complexes where X = O, R = aryl indicates that the molybdenum environment in the new models is electronically similar to that in Tp*MoO(benzenedithiolate).
Sharon J. Nieter Burgmayer, Mary Kim, Rebecca Petit, Amy Rothkopf, Alison Kim, Shadia BelHamdounia, Ying Hou, Arpad Somogyi, Diana Habel-Rodriguezc, Antonio Williams, Martin L. Kirk, "Synthesis, characterization, and spectroscopy of model molybdopterin complexes," Journal of Inorganic Biochemistry 2007 Nov;101(11-12):1601-16.