Synthesis and chloride affinity of sterically demanding ditopic lithium bis(pyrazol-1-yl)borates

The synthesis and full characterization of the sterically demanding ditopic lithium bis(pyrazol-1-yl)borates Li-2[p-C6H4(B(Ph)pzR(2))(2)] is reported (pz(R) = 3-phenylpyrazol-1-yl (3(Ph)), 3-t-butylpyrazol-1-yl (3(tBu))). Compound 3(Ph) crystallizes from THF as THF-adduct 3(Ph)(THF)(4) which features a straight conformation with a long Li center dot center dot center dot Li distance of 12.68(1) angstrom. Compound 3(tBu) was found to function as efficient and selective scavenger of chloride ions. In the presence of LiCl it forms anionic complexes [3(tBu)Cl](-) with a central Li-Cl-Li core (Li center dot center dot center dot Li = 3.75(1) angstrom).