Unusual polybrominated polypyrazolylborates and their copper(I) complexes: synthesis, characterization, and catalytic activity.

Five new homoscorpionate ligands were prepared and structurally characterized as their Tl complexes, three of which, Tl[TpBr,Ph,Br] (1) (Tp = hydrotris(pyrazolyl)borate, Tl[TpBr,p-Tomicronl,Br] (2), and Tl[TpBr,p-ClPh,Br] (3), are unique in being the first examples of an "atypical" B-N bond to the most sterically hindered pyrazole nitrogen. They contain bromine atoms on the central and outer carbons of the pyrazole ring, with all aryl substituents in the 5-position of the ligand, forming a protective pocket around the B-H bond. These complexes display a rather high B-H stretch frequency (above 2 600 cm-1) in the IR region.

Syntheses and solid state structures of tris(pyrazolyl)methane complexes of sodium, potassium, calcium, and strontium: comparison of structures with analogous complexes of lead(II).

The reaction of NaI with 2 equiv of HC(pz)(3) or HC(3,5-Me(2)pz)(3) (pz = pyrazolyl ring) leads to the formation of [[HC(pz)(3)](2)Na](I) (1) and [[HC(3,5-Me(2)pz)(3)](2)Na](I) (2), respectively. Both compounds have trigonally distorted octahedral arrangements about the sodium. A similar reaction of KPF(6) with HC(3,5-Me(2)pz)(3) results in the formation of [[HC(3,5-Me(2)pz)(3)](2)K](PF(6)) (3), a complex also shown crystallographically to have a trigonally distorted octahedral arrangement about the potassium, which is an unusually low coordination number for this large metal ion.