Adducts of a Triangular Copper(I) Pyrazolate with Thiophenic Compounds Featuring Short Cu(I)-S Contacts

The acidic triangular copper(I) 4-nitro-3,5-bis(trifluoromethyl)pyrazolate (Cu(3)pz(3)) and its adducts with thiophenic compounds were prepared and structurally characterized by X-ray diffraction. Except Cu(3)pz(3)DMDBT-L, the adducts, namely, Cu(3)pz(3)DBT, Cu(3)pz(3)DBT0.5C(7)H(8), Cu(3)pz(3)2DBT, Cu(3)pz(3)DMDBT-S, and Cu(3)pz(3)2DMT, feature a short intermolecular Cu-I-S-thienyl contact, ranging from 2.544 to 2.327 & Aring; (DBT = dibenzothiophene, DMDBT = 4,6-dimethyldibenzothiophene, DMT = 2,5-dimethylthiophene). Two kinds of crystals (colorless and yellow) can be differentiated by the Cu-S distance in the crystal structures of Cu(3)pz(3)DMDBT-L/S. By comparison of the structures reported here and those simulated for adsorption of thiophenic compounds over Cu(I)-containing adsorbents by theoretical calculations, it is suggested that Cu(3)pz(3) could be used as an efficient model compound of adsorbent to investigate the metal-promoted adsorptive desulfurization. A preliminary investigation has demonstrated that dibenzothiophene (DBT) can be effectively adsorbed by Cu(3)pz(3) from model oils.