Alkoxy-siloxide metal complexes: Precursors to metal silica, metal oxide silica, and metal silicate materials

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7273854

Terry, K W

The alkoxy-siloxide complexes M[OSi(O[sup t]Bu)[sub 3]][sub 4] [M = Ti(1), Zr(2), Hf(3)], were prepared by reaction with respective metal diethylamides. The compounds undergo low-temperature decomposition to their respective metal oxide silica materials (MO[sub 2]rSiO[sub 2]). The volatile products of the thermolysis of 2 (ca. 200[degrees]C) were isobutylene (11.7 equiv) and water (5.4 equiv). The ZrO[sub 2]4SiO[sub 2] material from the decomposition of 2 at 400[degrees]C was amorphous until ca. 1100[degrees]C where crystallization of t-ZrO[sub 2] occurred. After thermolysis to 1500[degrees]C, t-ZrO[sub 2] and cristobalite were the major products. The HfO[sub 2]4SiO[sub 2] material from the decomposition of 3 at 400[degrees]C was amorphous until ca. 1000[degrees]C where crystallization of c/t-HfO[sub 2] was observed. Thermolysis to 1460[degrees]C yielded c/t-HfO[sub 2], m-HfO[sub 2] and minor amounts of cristobalite. The crystallization of anatase in the TiO4SiO[sub 2] material from decomposed 1 at 400[degrees]C was apparent after thermolysis to 1000[degrees]C. Thermolysis to 1400[degrees]C gave a mixture of anatase, rutile, and cristobalite. Both 4 and 5 yield isobutylene upon thermolysis (ca. 200[degrees]C) and the crystallization of mullite occurs at 1034[degrees]C and 1017[degrees]C. The crystallization of mullite occurs at 1029[degrees]C. The compounds[CuOSi(O[sup t]Bu)[sub 3]][sub n] (6) and [CuOSi(O[sup t]Bu)[sub 2]Ph][sub 4] (7) were prepared by reaction with [CuO[sup t]Bu][sub 4]. The thermolysis of 6 at 1000[degrees]C under argon gave Cu[degrees] and amorphous silica. Thermolysis of 6 (ca 200[degrees]C) gave CuO and amorphous silica. Thermolysis of 6 (ca 200[degrees]C) yielded HOSi(O[sup t]Bu)[sub 3] with competitive sublimation of 6. The chemistry of these and other alkoxy-siloxide complexes will be discussed.

• Research Organization: California Univ., San Diego, CA (United States)
• OSTI ID: 7273854
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKOXIDES
AMIDES
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
MINERALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PRECURSOR
PYROLYSIS
SILICA
SILICATE MINERALS
SILICON COMPOUNDS
SILICON OXIDES
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES