Abstract: A scorpionate ligand K[HB{pz^An}₃]( pz^An=3-{p-methoxyphenyl}pyrazole) was prepared, which was reacted with one molar equivalent of Cu( O₂ CMe)₂ · H₂ Oin THFat room temperature, yielding [Cu( O₂ CMe) (HB{pz^An}₃) ](Ⅰ) .But the reaction of K[HB{pz^An}₃]with anhydrous Cu Cl₂ afforded CuCl(pz^AnH) (HB{pz^An}₃) (Ⅱ) .The EPR spectra of Ⅰand Ⅱ in benzene solution exhibit a pseudoaxial symmetrical {dx₂-y₂}¹ configuration at copper.Both Ⅰ and Ⅱ are characterized by IR, elementary analysis and CV.The crystal structure of compound Ⅱ has been determined.Crystals are monoclinic,space group P2₁/c with a=1 .1643( 2 ) nm,b=2 .7081 ( 5) nm,c=1 .4494( 3) nm,β= 10 5.37( 3)°,V=4.4066( 14) n m³ and Z=4,with final residuals R=0 .0604 and R_w=0 .1416.The complex shows a distorted square pyramidal copper center,and exhibits a weak intramolecular hydrogen bond,N_ H… Cl,with bond length of Cl… N 0 .300 9nm and bond angle of Cl… H _ N 12 0 .3°.

Key words: Poly( pyrazolyl) borate, Synthesis, Crystal structure, Intramolecular hydrogen bond