Volatility by Design. Synthesis and Characterization of Polyether Adducts of Bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)barium and Their Implementation as Metal-Organic Chemical Vapor Deposition Pr
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- 作者：John A. Belot ; Deborah A. Neumayer ; Charles J. Reedy ; Daniel B. Studebaker ; Bruce J. Hinds ; Charlotte L. Stern ; and Tobin J. Marks
- 刊名：Chemistry of Materials
- 出版年：1997
- 出版时间：July 1997
- 年：1997
- 卷：9
- 期：7
- 页码：1638 - 1648
- 全文大小：417K
- 年卷期：v.9,no.7(July 1997)
- ISSN：1520-5002
文摘
The synthesis and characterization of a series ofpolyethers and volatile, low-meltingpolyether complexes ofbis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)barium havingthegeneral formulaBa(hfa)2·RO(CH2CH2O)nR'where R = R' = CH3, n = 3; R =CH3, R' = C2H5,n = 3; R = R' = H, n = 5, 6; R = R' =CH3, n = 4; R = CH3, R' =C2H5, n = 5; R =CH3, R'= n-C4H9, n = 5, 6; R= CH3, R = C5H11O, n= 3; R = CH3, R' =n-C6H13, n = 4, 5; R= C2H5,R' = n-C4H9, n = 5; R= n-C4H9, R' =n-C4H9, n = 4, 6; R =n-C4H9, R' =n-C6H13, n = 5arereported. The complexes are conveniently synthesized by reactionof n-propylammonium+hfa- in DMF with an aqueous solution ofBa(NO3)2 and the polyether or,alternatively, byreaction of the polyether with Ba(hfa)2 in toluene.These new complexes were characterizedby elemental analysis, FT-IR, 1H, 13C, and19F NMR, MS, X-ray diffraction(Ba(hfa)2·CH3O(CH2CH2O)3CH3·H2O,Ba(hfa)2·CH3O(CH2CH2O)5C2H5),and thermogravimetric analysis. Themelting points of the complexes are strongly dependent on thearchitecture of the polyetherchain and dimensions of the terminal polyether substituent, with thelowest melting pointscorresponding to the longest polyethers having the largest terminalgroups. The volatilityof the Ba(hfa)2·polyether compounds isdependent on molecular weight and molecularstructure; however, there is little direct correlation between meltingpoint depression andenhanced volatility. The applicability of these complexes inmetal-organic chemical vapordeposition is demonstrated by the successful growth of phase-pureBaTiO3 thin films usingBa(hfa)2·CH3O(CH2CH2O)5C2H5as the Ba source. Phase composition and epitaxy inthesefilms is analyzed by energy-dispersive X-ray spectroscopy and X-raydiffraction 
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