Synthesis, characterization, and spectroscopy of model molybdopterin complexes.
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. 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 [Et(4)N][Tp(*)Mo(IV)(S)S(4)] 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 dithiolenes with electron-withdrawing substituents and simple dithiolates 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).
Burgmayer
Sharon J Nieter
SJ
Department of Chemistry, Bryn Mawr College, Bryn Mawr, PA 19010, USA. sburgmay@brynmawr.edu
Kim
Mary
M
Petit
Rebecca
R
Rothkopf
Amy
A
Kim
Alison
A
BelHamdounia
Shadia
S
Hou
Ying
Y
Somogyi
Arpad
A
Habel-Rodriguez
Diana
D
Williams
Antonio
A
Kirk
Martin L
ML
D002942:Circular Dichroism; D003067:Coenzymes / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D009682:Magnetic Resonance Spectroscopy; D008667:Metalloproteins / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D000090006:Molybdenum Cofactors; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D011621:Pteridines / Q000737:chemistry*; D011622:Pterins / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
D003067:Coenzymes; D008667:Metalloproteins; D000090006:Molybdenum Cofactors; D009942:Organometallic Compounds; D011621:Pteridines; D011622:Pterins; C490076:pyranopterin; C022261:molybdopterin