Surface Organometallic Chemistry of Inorganic Oxides: The Synthesis and Characterization of (≡SiO)Ta(=CHC(CH3)3)(CH2C(CH3)3)2and (≡SiO)2Ta(=CHC(CH3)3)(CH2C(CH3)3)

Véronique Dufaud; Gerald P. Niccolai; Jean Thivolle-Cazat; Jean Marie Basset

doi:10.1021/ja00120a010

Surface Organometallic Chemistry of Inorganic Oxides: The Synthesis and Characterization of (≡SiO)Ta(=CHC(CH₃)₃)(CH₂C(CH₃)₃)₂and (≡SiO)₂Ta(=CHC(CH₃)₃)(CH₂C(CH₃)₃)

Véronique Dufaud, Gerald P. Niccolai, Jean Thivolle-Cazat, Jean Marie Basset^*

^*Corresponding author for this work

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86 Scopus citations

Abstract

The synthesis of two silica-supported tantalum(V) carbene complexes is reported. The reaction of Ta- (=CHC(CH₃)₃)(CH₂C(CH₃)₃)₃ (1) with a silica dehydroxylated at 500 °C produces a mixture of (≡SiO)Ta(=CHC-(CH₃)₃)(CH₂C(CH₃)₃)₂(2a) and (≡SiO)₂Ta(=CHC(CH₃)₃)(CH₂C(CH₃)₃) (2b) and neopentane gas (on average 1.3 equiv/equiv of tantalum). The reaction of 2a/2b with water produces 2.6 mol of neopentane. The reaction of 2a/2b with acetone produces 1 equiv of 2,4,4-trimethyl-2-pentene per grafted tantalum, indicating that 2a,b each bear one carbene ligand. When 1 is reacted with fully (>90%) deuterated silica, the product neopentane is only 38% monodeuterated. The product of this reaction (2_deut) is hydrolyzed with D₂O to produce 2.6 equiv (per Ta) of neopentane as a mixture of neopentane-d₀, -d₁, -d₂, and -d₃ (3.3:54.4:36.7:5.5). The presence of neopentane-d₃ is evidence for the incorporation of deuterium into the tantalum surface complex during the synthesis of 2a/2b. The volatile product of the reaction of 2_deut with acetone is 1 equiv of 2,4,4-trimethyl-2-pentene which is 15% monodeuterated, demonstrating some incorporation of deuterium in the carbenic positions of 2_deut. The isotopomeric distribution in the volatile products of these reactions is traced to a mechanism of formation of 2a,b in which the first reaction of surface silanol with 1 is the addition of O—H across the Ta=C double bond.

Original language	English (US)
Pages (from-to)	4288-4294
Number of pages	7
Journal	Journal of the American Chemical Society
Volume	117
Issue number	15
DOIs	https://doi.org/10.1021/ja00120a010
State	Published - Apr 1995
Externally published	Yes

ASJC Scopus subject areas

Catalysis
General Chemistry
Biochemistry
Colloid and Surface Chemistry

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10.1021/ja00120a010

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@article{d524761ce7914e5d80ef72f8bf111940,

title = "Surface Organometallic Chemistry of Inorganic Oxides: The Synthesis and Characterization of (≡SiO)Ta(=CHC(CH3)3)(CH2C(CH3)3)2and (≡SiO)2Ta(=CHC(CH3)3)(CH2C(CH3)3)",

abstract = "The synthesis of two silica-supported tantalum(V) carbene complexes is reported. The reaction of Ta- (=CHC(CH3)3)(CH2C(CH3)3)3 (1) with a silica dehydroxylated at 500 °C produces a mixture of (≡SiO)Ta(=CHC-(CH3)3)(CH2C(CH3)3)2(2a) and (≡SiO)2Ta(=CHC(CH3)3)(CH2C(CH3)3) (2b) and neopentane gas (on average 1.3 equiv/equiv of tantalum). The reaction of 2a/2b with water produces 2.6 mol of neopentane. The reaction of 2a/2b with acetone produces 1 equiv of 2,4,4-trimethyl-2-pentene per grafted tantalum, indicating that 2a,b each bear one carbene ligand. When 1 is reacted with fully (>90%) deuterated silica, the product neopentane is only 38% monodeuterated. The product of this reaction (2deut) is hydrolyzed with D2O to produce 2.6 equiv (per Ta) of neopentane as a mixture of neopentane-d0, -d1, -d2, and -d3 (3.3:54.4:36.7:5.5). The presence of neopentane-d3 is evidence for the incorporation of deuterium into the tantalum surface complex during the synthesis of 2a/2b. The volatile product of the reaction of 2deut with acetone is 1 equiv of 2,4,4-trimethyl-2-pentene which is 15% monodeuterated, demonstrating some incorporation of deuterium in the carbenic positions of 2deut. The isotopomeric distribution in the volatile products of these reactions is traced to a mechanism of formation of 2a,b in which the first reaction of surface silanol with 1 is the addition of O—H across the Ta=C double bond.",

author = "V{\'e}ronique Dufaud and Niccolai, {Gerald P.} and Jean Thivolle-Cazat and Basset, {Jean Marie}",

year = "1995",

month = apr,

doi = "10.1021/ja00120a010",

language = "English (US)",

volume = "117",

pages = "4288--4294",

journal = "Journal of the American Chemical Society",

issn = "0002-7863",

publisher = "American Chemical Society",

number = "15",

}

Surface Organometallic Chemistry of Inorganic Oxides: The Synthesis and Characterization of (≡SiO)Ta(=CHC(CH₃)₃)(CH₂C(CH₃)₃)₂and (≡SiO)₂Ta(=CHC(CH₃)₃)(CH₂C(CH₃)₃). / Dufaud, Véronique; Niccolai, Gerald P.; Thivolle-Cazat, Jean et al.
In: Journal of the American Chemical Society, Vol. 117, No. 15, 04.1995, p. 4288-4294.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Surface Organometallic Chemistry of Inorganic Oxides

T2 - The Synthesis and Characterization of (≡SiO)Ta(=CHC(CH3)3)(CH2C(CH3)3)2and (≡SiO)2Ta(=CHC(CH3)3)(CH2C(CH3)3)

AU - Dufaud, Véronique

AU - Niccolai, Gerald P.

AU - Thivolle-Cazat, Jean

AU - Basset, Jean Marie

PY - 1995/4

Y1 - 1995/4

N2 - The synthesis of two silica-supported tantalum(V) carbene complexes is reported. The reaction of Ta- (=CHC(CH3)3)(CH2C(CH3)3)3 (1) with a silica dehydroxylated at 500 °C produces a mixture of (≡SiO)Ta(=CHC-(CH3)3)(CH2C(CH3)3)2(2a) and (≡SiO)2Ta(=CHC(CH3)3)(CH2C(CH3)3) (2b) and neopentane gas (on average 1.3 equiv/equiv of tantalum). The reaction of 2a/2b with water produces 2.6 mol of neopentane. The reaction of 2a/2b with acetone produces 1 equiv of 2,4,4-trimethyl-2-pentene per grafted tantalum, indicating that 2a,b each bear one carbene ligand. When 1 is reacted with fully (>90%) deuterated silica, the product neopentane is only 38% monodeuterated. The product of this reaction (2deut) is hydrolyzed with D2O to produce 2.6 equiv (per Ta) of neopentane as a mixture of neopentane-d0, -d1, -d2, and -d3 (3.3:54.4:36.7:5.5). The presence of neopentane-d3 is evidence for the incorporation of deuterium into the tantalum surface complex during the synthesis of 2a/2b. The volatile product of the reaction of 2deut with acetone is 1 equiv of 2,4,4-trimethyl-2-pentene which is 15% monodeuterated, demonstrating some incorporation of deuterium in the carbenic positions of 2deut. The isotopomeric distribution in the volatile products of these reactions is traced to a mechanism of formation of 2a,b in which the first reaction of surface silanol with 1 is the addition of O—H across the Ta=C double bond.

AB - The synthesis of two silica-supported tantalum(V) carbene complexes is reported. The reaction of Ta- (=CHC(CH3)3)(CH2C(CH3)3)3 (1) with a silica dehydroxylated at 500 °C produces a mixture of (≡SiO)Ta(=CHC-(CH3)3)(CH2C(CH3)3)2(2a) and (≡SiO)2Ta(=CHC(CH3)3)(CH2C(CH3)3) (2b) and neopentane gas (on average 1.3 equiv/equiv of tantalum). The reaction of 2a/2b with water produces 2.6 mol of neopentane. The reaction of 2a/2b with acetone produces 1 equiv of 2,4,4-trimethyl-2-pentene per grafted tantalum, indicating that 2a,b each bear one carbene ligand. When 1 is reacted with fully (>90%) deuterated silica, the product neopentane is only 38% monodeuterated. The product of this reaction (2deut) is hydrolyzed with D2O to produce 2.6 equiv (per Ta) of neopentane as a mixture of neopentane-d0, -d1, -d2, and -d3 (3.3:54.4:36.7:5.5). The presence of neopentane-d3 is evidence for the incorporation of deuterium into the tantalum surface complex during the synthesis of 2a/2b. The volatile product of the reaction of 2deut with acetone is 1 equiv of 2,4,4-trimethyl-2-pentene which is 15% monodeuterated, demonstrating some incorporation of deuterium in the carbenic positions of 2deut. The isotopomeric distribution in the volatile products of these reactions is traced to a mechanism of formation of 2a,b in which the first reaction of surface silanol with 1 is the addition of O—H across the Ta=C double bond.

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U2 - 10.1021/ja00120a010

DO - 10.1021/ja00120a010

M3 - Article

AN - SCOPUS:0001649048

SN - 0002-7863

VL - 117

SP - 4288

EP - 4294

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 15

ER -

Surface Organometallic Chemistry of Inorganic Oxides: The Synthesis and Characterization of (≡SiO)Ta(=CHC(CH₃)₃)(CH₂C(CH₃)₃)₂and (≡SiO)₂Ta(=CHC(CH₃)₃)(CH₂C(CH₃)₃)

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