Synthesis and characterization of calcium complexes containing eta(2)-pyrazolato ligands

Treatment of calcium bromide with 3,5-di-tert-butylpyrazolatopotassium (2 e quiv) in tetrahydrofuran afforded Ca(tBu(2)pz)(2)(THF)(2) (69%). The reacti on of this compound with pyridine (3 equiv), tetramethylethylenediamine (TM EDA, 1 equiv), N,N,N',N',N"-pentamethyldiethyleneuiamine (PMDETA, 1 equiv), triglyme (1 equiv), and tetraglyme (1 equiv) yielded Ca(tBu(2)pz)(2)(py)(3 ) (51%), Ca(tBu(2)pz)(2)(TMEDA) (74%), Ca(tBu(2)pz)(2)(PMDETA) (50%), Ca(tB u(2)pz)(2)(triglyme) (73%), and Ca(tBu(2)pz)(2)(tetraglyme) (57%), respecti vely. Treatment of the tetrahydrofuran adduct of Ca(Me(2)pz)(2), generated in situ, with PMDETA (1 equiv), triglyme (1 equiv), and tetraglyme (1 equiv ) afforded Ca(Me(2)pz)(2)(PMDETA) (65%), Ca(Me(2)pz)(2)(triglyme) (54%), an d Ca(Me(2)pz)(2)(tetraglyme) (40%), respectively. The X-ray crystal structu res of Ca(tBu(2)pz)(2)(py)(3), Ca(tBu(2)pz)(2)(TMEDA), Ca(tBu(2)pz)(2)(PMDE TA), Ca(tBu(2)pz)(2)(triglyme), and Ca(Me(2)pz)(2)(PMDETA) revealed six-, s even-, or eight-coordinate calcium centers with eta(2)-pyrazolato ligands. Ca(tBu(2)pz)(2)(triglyme) sublimes at 160 degrees C (0.1 mmHg). The potenti al utility of these complexes as source compounds for chemical vapor deposi tion processes is discussed.