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Synthesis and Characterization of Tris(trimethylsilyl)siloxide Derivatives of Early Transition Metal Alkoxides That Thermally Convert to Varied Ceramic–Silica Architecture Materials
In an effort to generate single-source precursors for the production of metal-siloxide (MSiOx) materials, the tris(trimethylsilyl)silanol (H-SST or H-OSi(SiMe3)3 (1) ligand was reacted with a series of group 4 and 5 metal alkoxides. The group 4 products were crystallographically characterized as: [Ti(SST)2(OR)2] (OR = OPri (2), OBut (3), ONep (4)); [Ti(SST)3(OBun)] (5); [Zr(SST)2(OBut)2(py)] (6); [Zr(SST)3(OR)] (OR = OBut(7), ONep, (8)); [Hf(SST)2(OBut)2] (9); and [Hf(SST)2(ONep)2(py)n] (n = 1 (10) , n = 2 (10a)) where OPri = OCH(CH3)2, OBut = OC(CH3)3, OBun = O(CH2)3CH3, ONep = OCH2C(CH3)3, py = pyridine. The crystal structures revealed SST substituted: monomeric Ti species that adopted a tetrahedral (T-4) geometry; monomeric Zr compounds with coordination that varied from T-4 to trigonal bipyramidal (TBPY- 5); and monomeric Hf complexes isolated in a TBPY-5 geometry. For the group 5 species, the following derivatives were structurally identified as: [V(SST)3(py)2] (11), [Nb(SST)3(OEt)2] (12), [Nb(0)(SST)3(py)] (13), 2[H][(Nb(μ-0)2(SST))6(μ6-0)] (14), [Nb8O10(OEt)18(SST)2•1/5Na2O] (15), [Ta(SST)([μ-OEt)(OEt)3]2(16), and [Ta(SST)3(OEt)2] (17) where OEt = OCH2CH3. The group 5 monomeric complexes were solved in a TBPY-5 arrangement, whereas the Ta of the dinculear 16 was solved in an octahedral coordination environment. Thermal analyses of these precursors revealed a stepwise loss of ligand, which indicated their potential utility for generating the MSiOx, materials. The complexes were thermally processed (350 - 1100 °C, 4h, ambient atmosphere) but instead of the desired MSiOx, transmission electron microscopy analyses revealed fractions of the group 4 and group 5 precursors had formed unusual architectures.
Boyle, Timothy J., et al. "Synthesis and Characterization of Tris(trimethylsilyl)siloxide Derivatives of Early Transition Metal Alkoxides That Thermally Convert to Varied Ceramic–Silica Architecture Materials." Inorganic Chemistry, vol. 57, no. 15, Jul. 2018. https://doi.org/10.1021/acs.inorgchem.8b00630
Boyle, Timothy J., Sears, Jeremiah M., Perales, Diana, Cramer, Roger E., Lu, Ping, Chan, Rana O., & Hernandez-Sanchez, Bernadette A. (2018). Synthesis and Characterization of Tris(trimethylsilyl)siloxide Derivatives of Early Transition Metal Alkoxides That Thermally Convert to Varied Ceramic–Silica Architecture Materials. Inorganic Chemistry, 57(15). https://doi.org/10.1021/acs.inorgchem.8b00630
Boyle, Timothy J., Sears, Jeremiah M., Perales, Diana, et al., "Synthesis and Characterization of Tris(trimethylsilyl)siloxide Derivatives of Early Transition Metal Alkoxides That Thermally Convert to Varied Ceramic–Silica Architecture Materials," Inorganic Chemistry 57, no. 15 (2018), https://doi.org/10.1021/acs.inorgchem.8b00630
@article{osti_1473938,
author = {Boyle, Timothy J. and Sears, Jeremiah M. and Perales, Diana and Cramer, Roger E. and Lu, Ping and Chan, Rana O. and Hernandez-Sanchez, Bernadette A.},
title = {Synthesis and Characterization of Tris(trimethylsilyl)siloxide Derivatives of Early Transition Metal Alkoxides That Thermally Convert to Varied Ceramic–Silica Architecture Materials},
annote = {In an effort to generate single-source precursors for the production of metal-siloxide (MSiOx) materials, the tris(trimethylsilyl)silanol (H-SST or H-OSi(SiMe3)3 (1) ligand was reacted with a series of group 4 and 5 metal alkoxides. The group 4 products were crystallographically characterized as: [Ti(SST)2(OR)2] (OR = OPri (2), OBut (3), ONep (4)); [Ti(SST)3(OBun)] (5); [Zr(SST)2(OBut)2(py)] (6); [Zr(SST)3(OR)] (OR = OBut(7), ONep, (8)); [Hf(SST)2(OBut)2] (9); and [Hf(SST)2(ONep)2(py)n] (n = 1 (10) , n = 2 (10a)) where OPri = OCH(CH3)2, OBut = OC(CH3)3, OBun = O(CH2)3CH3, ONep = OCH2C(CH3)3, py = pyridine. The crystal structures revealed SST substituted: monomeric Ti species that adopted a tetrahedral (T-4) geometry; monomeric Zr compounds with coordination that varied from T-4 to trigonal bipyramidal (TBPY- 5); and monomeric Hf complexes isolated in a TBPY-5 geometry. For the group 5 species, the following derivatives were structurally identified as: [V(SST)3(py)2] (11), [Nb(SST)3(OEt)2] (12), [Nb(0)(SST)3(py)] (13), 2[H][(Nb(μ-0)2(SST))6(μ6-0)] (14), [Nb8O10(OEt)18(SST)2•1/5Na2O] (15), [Ta(SST)([μ-OEt)(OEt)3]2(16), and [Ta(SST)3(OEt)2] (17) where OEt = OCH2CH3. The group 5 monomeric complexes were solved in a TBPY-5 arrangement, whereas the Ta of the dinculear 16 was solved in an octahedral coordination environment. Thermal analyses of these precursors revealed a stepwise loss of ligand, which indicated their potential utility for generating the MSiOx, materials. The complexes were thermally processed (350 - 1100 °C, 4h, ambient atmosphere) but instead of the desired MSiOx, transmission electron microscopy analyses revealed fractions of the group 4 and group 5 precursors had formed unusual architectures.},
doi = {10.1021/acs.inorgchem.8b00630},
url = {https://www.osti.gov/biblio/1473938},
journal = {Inorganic Chemistry},
issn = {ISSN 0020-1669},
number = {15},
volume = {57},
place = {United States},
publisher = {American Chemical Society (ACS)},
year = {2018},
month = {07}}
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