Surface Organometallic Chemistry on Metals. Evidence for a New Surface Organometallic Material, Rh[Sn(n-C4H9)x]y/ SiO2, Obtained by Controlled Hydrogenolysis of Sn(n-C4H9)4 on a Rh/SiO2 Catalyst

B. Didillon; C. Houtman; J. P. Candy; J. M. Basset; T. Shay

doi:10.1021/ja00074a003

Surface Organometallic Chemistry on Metals. Evidence for a New Surface Organometallic Material, Rh[Sn(n-C₄H₉)_x]_y/ SiO₂, Obtained by Controlled Hydrogenolysis of Sn(n-C₄H₉)₄ on a Rh/SiO₂ Catalyst

B. Didillon, C. Houtman, J. P. Candy^*, J. M. Basset, T. Shay

^*Corresponding author for this work

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

65 Scopus citations

Abstract

Selective hydrogenolysis of Sn(n-C₄H₉)₄ on a Rh/SiO₂ catalyst has been carried out at various temperatures and at various coverages of the metallic surface. The surface reaction and the characterization of the grafted organotin complex have been followed by analytical methods, temperature-programmed reaction, electron microscopy, XPS, IR, Mössbauer spectroscopy, ¹³C CP-MAS solid-state NMR. At room temperature and in the absence of metallic Rh, Sn(n-C₄H₉)4 is simply physisorbed on the silica surface and can be easily extracted. In the presence of metallic Rh, and provided that the amount of Sn introduced represents less than a monolayer on the metallic surface, the hydrogenolysis of Sn(n-C₄H₉)₄ occurs exclusively on the Rh particle. Only a ¹³C NMR signal corresponding to ≡SiOSn(n-C₄H₉)₃ was observed on the silica surface when the amount of Sn introduced was higher than ca. one monolayer on the Rh particle. Sn remains on this metallic phase even after hydrogenolysis, as demonstrated by STEM-EDAX experiments. Gas-phase evolution (TPR) and infrared studies show that the hydrogenolysis proceeds by a stepwise cleavage of Sn-alkyl bonds. For low Sn/Rh_s ratios (<0.5) the reaction is continuous with formation of surface tin alkyl complexes with various degrees of substitution. For higher Sn/Rh_s ratios, there is formation of a well-defined and relatively stable surface organometallic fragment which can be formulated as Rh_s[Sn(n-C₄H₉)₂]_y. Various possible structures have been proposed, taking into account the various results. Whereas Rh_s[Sn(n-C₄H₉)₂]_y is the simplest possible model for this stable surface organometallic fragment, the results of molecular modeling seem to rule out such a model (at least at high coverages) on the basis of steric constraints. Another model, which apparently fits the experimental results better, corresponds to the general formula (Rh_s)₂Sn[Sn(n-C₄H₉)₃]₂.

Original language	English (US)
Pages (from-to)	9380-9388
Number of pages	9
Journal	Journal of the American Chemical Society
Volume	115
Issue number	21
DOIs	https://doi.org/10.1021/ja00074a003
State	Published - Oct 1 1993
Externally published	Yes

ASJC Scopus subject areas

Catalysis
General Chemistry
Biochemistry
Colloid and Surface Chemistry

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10.1021/ja00074a003

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@article{57c30339e4b04fd486e0244ae1186aec,

title = "Surface Organometallic Chemistry on Metals. Evidence for a New Surface Organometallic Material, Rh[Sn(n-C4H9)x]y/ SiO2, Obtained by Controlled Hydrogenolysis of Sn(n-C4H9)4 on a Rh/SiO2 Catalyst",

abstract = "Selective hydrogenolysis of Sn(n-C4H9)4 on a Rh/SiO2 catalyst has been carried out at various temperatures and at various coverages of the metallic surface. The surface reaction and the characterization of the grafted organotin complex have been followed by analytical methods, temperature-programmed reaction, electron microscopy, XPS, IR, M{\"o}ssbauer spectroscopy, 13C CP-MAS solid-state NMR. At room temperature and in the absence of metallic Rh, Sn(n-C4H9)4 is simply physisorbed on the silica surface and can be easily extracted. In the presence of metallic Rh, and provided that the amount of Sn introduced represents less than a monolayer on the metallic surface, the hydrogenolysis of Sn(n-C4H9)4 occurs exclusively on the Rh particle. Only a 13C NMR signal corresponding to ≡SiOSn(n-C4H9)3 was observed on the silica surface when the amount of Sn introduced was higher than ca. one monolayer on the Rh particle. Sn remains on this metallic phase even after hydrogenolysis, as demonstrated by STEM-EDAX experiments. Gas-phase evolution (TPR) and infrared studies show that the hydrogenolysis proceeds by a stepwise cleavage of Sn-alkyl bonds. For low Sn/Rhs ratios (<0.5) the reaction is continuous with formation of surface tin alkyl complexes with various degrees of substitution. For higher Sn/Rhs ratios, there is formation of a well-defined and relatively stable surface organometallic fragment which can be formulated as Rhs[Sn(n-C4H9)2]y. Various possible structures have been proposed, taking into account the various results. Whereas Rhs[Sn(n-C4H9)2]y is the simplest possible model for this stable surface organometallic fragment, the results of molecular modeling seem to rule out such a model (at least at high coverages) on the basis of steric constraints. Another model, which apparently fits the experimental results better, corresponds to the general formula (Rhs)2Sn[Sn(n-C4H9)3]2.",

author = "B. Didillon and C. Houtman and Candy, {J. P.} and Basset, {J. M.} and T. Shay",

year = "1993",

month = oct,

day = "1",

doi = "10.1021/ja00074a003",

language = "English (US)",

volume = "115",

pages = "9380--9388",

journal = "Journal of the American Chemical Society",

issn = "0002-7863",

publisher = "American Chemical Society",

number = "21",

}

Didillon, B, Houtman, C, Candy, JP, Basset, JM & Shay, T 1993, 'Surface Organometallic Chemistry on Metals. Evidence for a New Surface Organometallic Material, Rh[Sn(n-C₄H₉)_x]_y/ SiO₂, Obtained by Controlled Hydrogenolysis of Sn(n-C₄H₉)₄ on a Rh/SiO₂ Catalyst', Journal of the American Chemical Society, vol. 115, no. 21, pp. 9380-9388. https://doi.org/10.1021/ja00074a003

Surface Organometallic Chemistry on Metals. Evidence for a New Surface Organometallic Material, Rh[Sn(n-C₄H₉)_x]_y/ SiO₂, Obtained by Controlled Hydrogenolysis of Sn(n-C₄H₉)₄ on a Rh/SiO₂ Catalyst. / Didillon, B.; Houtman, C.; Candy, J. P. et al.
In: Journal of the American Chemical Society, Vol. 115, No. 21, 01.10.1993, p. 9380-9388.

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

TY - JOUR

T1 - Surface Organometallic Chemistry on Metals. Evidence for a New Surface Organometallic Material, Rh[Sn(n-C4H9)x]y/ SiO2, Obtained by Controlled Hydrogenolysis of Sn(n-C4H9)4 on a Rh/SiO2 Catalyst

AU - Didillon, B.

AU - Houtman, C.

AU - Candy, J. P.

AU - Basset, J. M.

AU - Shay, T.

PY - 1993/10/1

Y1 - 1993/10/1

N2 - Selective hydrogenolysis of Sn(n-C4H9)4 on a Rh/SiO2 catalyst has been carried out at various temperatures and at various coverages of the metallic surface. The surface reaction and the characterization of the grafted organotin complex have been followed by analytical methods, temperature-programmed reaction, electron microscopy, XPS, IR, Mössbauer spectroscopy, 13C CP-MAS solid-state NMR. At room temperature and in the absence of metallic Rh, Sn(n-C4H9)4 is simply physisorbed on the silica surface and can be easily extracted. In the presence of metallic Rh, and provided that the amount of Sn introduced represents less than a monolayer on the metallic surface, the hydrogenolysis of Sn(n-C4H9)4 occurs exclusively on the Rh particle. Only a 13C NMR signal corresponding to ≡SiOSn(n-C4H9)3 was observed on the silica surface when the amount of Sn introduced was higher than ca. one monolayer on the Rh particle. Sn remains on this metallic phase even after hydrogenolysis, as demonstrated by STEM-EDAX experiments. Gas-phase evolution (TPR) and infrared studies show that the hydrogenolysis proceeds by a stepwise cleavage of Sn-alkyl bonds. For low Sn/Rhs ratios (<0.5) the reaction is continuous with formation of surface tin alkyl complexes with various degrees of substitution. For higher Sn/Rhs ratios, there is formation of a well-defined and relatively stable surface organometallic fragment which can be formulated as Rhs[Sn(n-C4H9)2]y. Various possible structures have been proposed, taking into account the various results. Whereas Rhs[Sn(n-C4H9)2]y is the simplest possible model for this stable surface organometallic fragment, the results of molecular modeling seem to rule out such a model (at least at high coverages) on the basis of steric constraints. Another model, which apparently fits the experimental results better, corresponds to the general formula (Rhs)2Sn[Sn(n-C4H9)3]2.

AB - Selective hydrogenolysis of Sn(n-C4H9)4 on a Rh/SiO2 catalyst has been carried out at various temperatures and at various coverages of the metallic surface. The surface reaction and the characterization of the grafted organotin complex have been followed by analytical methods, temperature-programmed reaction, electron microscopy, XPS, IR, Mössbauer spectroscopy, 13C CP-MAS solid-state NMR. At room temperature and in the absence of metallic Rh, Sn(n-C4H9)4 is simply physisorbed on the silica surface and can be easily extracted. In the presence of metallic Rh, and provided that the amount of Sn introduced represents less than a monolayer on the metallic surface, the hydrogenolysis of Sn(n-C4H9)4 occurs exclusively on the Rh particle. Only a 13C NMR signal corresponding to ≡SiOSn(n-C4H9)3 was observed on the silica surface when the amount of Sn introduced was higher than ca. one monolayer on the Rh particle. Sn remains on this metallic phase even after hydrogenolysis, as demonstrated by STEM-EDAX experiments. Gas-phase evolution (TPR) and infrared studies show that the hydrogenolysis proceeds by a stepwise cleavage of Sn-alkyl bonds. For low Sn/Rhs ratios (<0.5) the reaction is continuous with formation of surface tin alkyl complexes with various degrees of substitution. For higher Sn/Rhs ratios, there is formation of a well-defined and relatively stable surface organometallic fragment which can be formulated as Rhs[Sn(n-C4H9)2]y. Various possible structures have been proposed, taking into account the various results. Whereas Rhs[Sn(n-C4H9)2]y is the simplest possible model for this stable surface organometallic fragment, the results of molecular modeling seem to rule out such a model (at least at high coverages) on the basis of steric constraints. Another model, which apparently fits the experimental results better, corresponds to the general formula (Rhs)2Sn[Sn(n-C4H9)3]2.

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U2 - 10.1021/ja00074a003

DO - 10.1021/ja00074a003

M3 - Article

AN - SCOPUS:0000942440

SN - 0002-7863

VL - 115

SP - 9380

EP - 9388

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 21

ER -

Surface Organometallic Chemistry on Metals. Evidence for a New Surface Organometallic Material, Rh[Sn(n-C₄H₉)_x]_y/ SiO₂, Obtained by Controlled Hydrogenolysis of Sn(n-C₄H₉)₄ on a Rh/SiO₂ Catalyst

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