COORDINATION CHEMISTRY OF THE STERICALLY HINDERED N-3-DONOR HYDROTRIS(3,5-DIPHENYLPYRAZOL-1-YL)BORATE TOWARD SILVER(I) TRIORGANOPHOSPHINO COMPOUNDS - SYNTHESIS, STRUCTURAL AND SPECTROSCOPIC CHARACTERIZATION

The interaction between Ag( O3SCF3), trialkyl- or triaryl-phosphine li gands (PR3: R = phenyl, o-, m- and p-tolyl, benzyl; PMePh2), and the a nionic N-3-donor tris(3,5-diphenylpyrazol-1-yl)borate [Tp(Ph2)] in tet rahydrofuran or methanol gives new air-stable and highly soluble 1:1 [ Tp(Ph2)] Ag {PR3} and [Tp(Ph2)] Ag{PMePh2} compounds. The tricyclohexy lphosphine (PCy3) is able to displace PPh3 and PBz(3) from the coordin ation sphere of silver(I), yielding the derivative [Tp(Ph2)] Ag{PCy3}. In contrast, imidazole, 1-methylmercaptoimidazole, 1,10-phenanthrolin e and 2,9-dimethyl-1,10-phenanthroline are not able to displace either phosphine or [TpPh2] from the coordination center. Reaction of Ag(O3S CF3) with 1 equiv. of [Tp(Ph2)] and CNR (R=Cy or Bu-t) yields the air- stable neutral compounds [Tp(Ph2)]Ag(CNR). When the reaction between [ Tp(Ph2)] and Ag(O3SCF3) is carried out in tetrahydrofuran at -70 degre es C in the absence of the phosphorus donor, breaking of the B-N bond occurs in the anionic ligand and the ionic compound [(3,5-Ph(2)PzH)(3) Ag](O3SCF3).(H2O)(2) was obtained from the reaction solution. All the derivatives were characterized through elemental analyses, spectral da ta (IR,H-1, P-31 and C-13 NMR) and conductivity measurements. Comparis on is made with the results previously obtained with other tris(pyrazo l-1-yl)borates. The solid state structures of [Tp(Ph2)]Ag{PPh3} and [T p(Ph2)]Ag{PBz(3)}. 2/3CHCl(3) show that the silver atom adopts a disto rted tetrahedral geometry with the donor [Tp(Ph2)] coordinating in tri dentate fashion. (C) 1998 Elsevier Science S.A. All rights reserved.