Spectroscopic studies in Ni2+ Stellacyanin from Rhus vernicifera

FERNÁNDEZ, C.O.; SANNAZZARO, A.I.; VILA, A.J.

Santiago, Chile

Congreso; XXXII International Conference on Coordination Chemistry; 1997

Sociedad Chilena de Química

 Stellacyanin (St hereafter), originally isolated from the Japanese lacquer tree Rhus vernicifera , has been considered as a chemical puzzle for more than 20 years since all crystallization attempts and spectroscopic studies failed to unveil the structure of the metal site. We have studied the Ni(II) derivative of stellacyanin by paramagnetic H NMR spectroscopy. The NMR spectrum resembles that ofNi(I1) Met l21Glnazurin, indicating a similar coordination environment. The characteristics of the assigned signals indicate that the metal center is tethraedral in Ni(II)-St. These data represent additional evidence for a Gln side chain in the axial ligand position os St.