Inorganic Chemistry, Vol.39, No.11, 2377-2384, 2000
Synthesis and characterization of calcium complexes containing eta(2)-pyrazolato ligands
Treatment of calcium bromide with 3,5-di-tert-butylpyrazolatopotassium (2 equiv) in tetrahydrofuran afforded Ca(tBu(2)pz)(2)(THF)(2) (69%). The reaction of this compound with pyridine (3 equiv), tetramethylethylenediamine (TMEDA, 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(tBu(2)pz)(2)(triglyme) (73%), and Ca(tBu(2)pz)(2)(tetraglyme) (57%), respectively. 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%), and Ca(Me(2)pz)(2)(tetraglyme) (40%), respectively. The X-ray crystal structures of Ca(tBu(2)pz)(2)(py)(3), Ca(tBu(2)pz)(2)(TMEDA), Ca(tBu(2)pz)(2)(PMDETA), Ca(tBu(2)pz)(2)(triglyme), and Ca(Me(2)pz)(2)(PMDETA) revealed six-, seven-, 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 potential utility of these complexes as source compounds for chemical vapor deposition processes is discussed.
Keywords:CHEMICAL-VAPOR-DEPOSITION;ORGANOAMIDO-LANTHANOIDS;ARYLOXO-LANTHANOIDS;THIN-FILMS;SUPERCONDUCTING ELECTRONICS;ORGANOMETALLIC COMPOUNDS;PYRAZOLATE LIGANDS;BARIUM-TITANATE;METAL;PRECURSORS