A green approach to the preparation of triangular silver(I) 3,5-bis(trifluoromethyl)pyrazolate: crystal structures of two adducts with triethylammonium nitrate or benzoic acid

Abstract

An improved procedure is described herein for the synthesis of triangular Ag(I) 3,5-bis(trifluoromethyl)pyrazolate ({[3,5-(CF3)2Pz]Ag}3), which involves initial preparation of its adducts with triethylammonium nitrate or benzoic acid, namely {[3,5-(CF3)2Pz]Ag}3·(Et3NH·NO3)2 (1) and {[3,5-(CF3)2Pz]Ag}3·(PhCOOH)2 (2), followed by removal of the nitrate and benzoic acid by washing or extraction with water to afford the pristine trisilver complex {[3,5-(CF3)2Pz]Ag}3. X-ray diffraction analysis on 1 and 2 reveals that {[3,5-(CF3)2Pz]Ag}3, acting as a π-acidic host, can combine with guest molecules/ions (NO3−, PhCOOH) by weak Ag–O/C coordination bonds, π–π stacking and C–H···F interactions. Our proposed synthetic procedure for {[3,5-(CF3)2Pz]Ag}3 can be easily carried out at room temperature, without using complex Schlenk techniques or hazardous organic solvents such as benzene and toluene, thus representing a green and facile approach to this well-recognized π-acidic complex.