Small scorpionate ligands: silver(I)-organophosphane complexes of 5-CF(3)-substituted scorpionate ligand combining a B-H...Ag coordination motif.

The first 5-substituted trihydro(azolyl)borate system, the sodium trihydro(5-CF3-pyrazol-1-yl)borate, Na[H3B(5-(CF3)pz)], has been synthesized by the reaction of 3-trifuoromethyl-pyrazole with NaBH4 in high yield. Na[H3B(5-(CF3)pz)] reacts with AgNO3 in the presence of monodentate tertiary phosphanes PR3 (PR3=P(C6H5)3, P(p-C6H4CH3)3, P(m-C6H4CH3)3, P(o-C6H4CH3)3, or PCH3(C6H5)2) to afford silver(I) bis(phosphane) adducts. These compounds have been characterized by elemental analyses, FTIR, ESI-MS, and multinuclear (1H, 19F, and 31P) NMR spectroscopy. Solid-state structures of {[H3B(5-(CF3)pz)]Ag[P(C6H5)3]2} and {[H3B(5-(CF3)pz)]Ag[P(p-C6H4CH3)3]2} are also reported. They feature kappa2-N,H-bonded trihydro(pyrazolyl)borate ligands and pseudo-tetrahedral silver atoms.