The effect of sulfur on CVD performance of Pd(II) β-diketonate precursors and the completion of a structural trans-influence series: synthesis and structural characterization of Pd(S,S-tmhd)2

Abstract The three complexes, Pd(tmhd) 2 ( 1 ), Pd( S -tmhd) 2 ( 2 ), and Pd( S , S -tmhd) 2 ( 3 ) (where tmhd, S -tmhd, and S , S -tmhd are the anions of 2,2,6,6-tetramethyl-3,5-heptanedione, 2,2,6,6-tetramethyl-5-thioxo-3-heptanone, and 2,2,6,6-tetramethyl-3,5-heptanedithione, respectively) were prepared and characterized by thermogravimetric analysis in order to assess their relative volatilities as a function of sulfur substitution. Complexes 1 and 2 volatilized with little residue, while 3 experienced significant decomposition during volatilization. The solid-state structure of 3 was determined in order to complete a structural trans -influence series with 1 and 2 and to assess possible reasons for its lower thermal stability. A large trans -influence was observed for the bond lengths in the coordination sphere across the series of complexes 1 , 2 , and 3 . The longer Pd–S bond distances found in 3 may be a contributing factor to its unsuitability as a CVD precursor.