To study the coordination action of pyrazolylborato ligands, KBHR3 (R = 3,5-dimethylpyrazol-1-yl) and Cu(BHR3)2 were prepared, and their crystal structures were determine by x-ray anal. The crystallog. data are as follows: KBHR3, monoclinic, space group P21/n, and R = 0.079; Cu(BHR3)2 triclinic, space group P1, Z = 2, and R = 0.062. The distance between atom K(1) and B(1) is 0.3634 nm. Atom B(1) in BHR3- is tetrahedrally coordinated by one H atom and three N atoms from three pyrazole rings. The bond distances B(1)-N(12), B(1)-N(22) and B(1)-N(32) are 0.1587, 0.1586 and 0.1509 nm, resp. In Cu(BHR3)2, the Cu atom is located about a crystallog. center of symmetry and coordinated octahedrally by six N atoms which are from two BHR3- ligands. The bond distances Cu(1)-N(11), Cu(1)-N(21) and Cu(1)-N(31) are 0.2153, 0.2344 and 0.2035 nm, resp. An obvious Jahn-Teller effect is displayed.

Key words: CRYSTAL STRUCTURE DETERMINATION, PYRAZOLE P, COPPER COMPLEX, BORATES P, POTASSIUM COMPLEX, JAHN-TELLER EFFECT, COORDINATION