Hydrosilylation of Aldehydes and Formates Using a Dimeric Manganese Precatalyst

Tufan K. Mukhopadhyay; Chandrani Ghosh; Marco Flores; Thomas L. Groy; Ryan J. Trovitch

doi:10.1021/acs.organomet.7b00423

Hydrosilylation of Aldehydes and Formates Using a Dimeric Manganese Precatalyst

Tufan K. Mukhopadhyay, Chandrani Ghosh, Marco Flores, Thomas L. Groy, Ryan J. Trovitch

Molecular Sciences, School of (SMS)

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

40 Scopus citations

Abstract

The formally zero-valent Mn dimer [(^Ph2PEtPDI)Mn]₂ has been synthesized upon reducing (^Ph2PEtPDI)MnCl₂ with excess Na/Hg. Single crystal X-ray diffraction analysis has revealed that [(^Ph2PEtPDI)Mn]₂ possesses a η⁴-PDI chelate about each Mn center, as well as η²-imine coordination across the dimer. The chelate metrical parameters suggest single electron PDI reduction and EPR spectroscopic analysis afforded a signal consistent with two weakly interacting S = ¹/₂ Mn centers. At ambient temperature in the absence of solvent, [(^Ph2PEtPDI)Mn]₂ has been found to catalyze the hydrosilylation of aldehydes at loadings as low as 0.005 mol % (0.01 mol % relative to Mn) with a maximum turnover frequency of 9,900 min^-1 (4,950 min^-1 per Mn). Moreover, the [(^Ph2PEtPDI)Mn]₂-catalyzed dihydrosilylation of formates has been found to proceed with turnover frequencies of up to 330 min^-1 (165 min^-1 relative to Mn). These metrics are comparable to those described for the leading Mn catalyst for this transformation, the propylene-bridged variant (^Ph2PPrPDI)Mn; however, [(^Ph2PEtPDI)Mn]₂ is more easily inhibited by donor functionalities. Carbonyl and carboxylate hydrosilylation is believed to proceed through a modified Ojima mechanism following dimer dissociation.

Original language	English (US)
Pages (from-to)	3477-3483
Number of pages	7
Journal	Organometallics
Volume	36
Issue number	18
DOIs	https://doi.org/10.1021/acs.organomet.7b00423
State	Published - Sep 25 2017

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Organic Chemistry
Inorganic Chemistry

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10.1021/acs.organomet.7b00423

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@article{76b7bc58a70d4e6885864115e7f88bdb,

title = "Hydrosilylation of Aldehydes and Formates Using a Dimeric Manganese Precatalyst",

abstract = "The formally zero-valent Mn dimer [(Ph2PEtPDI)Mn]2 has been synthesized upon reducing (Ph2PEtPDI)MnCl2 with excess Na/Hg. Single crystal X-ray diffraction analysis has revealed that [(Ph2PEtPDI)Mn]2 possesses a η4-PDI chelate about each Mn center, as well as η2-imine coordination across the dimer. The chelate metrical parameters suggest single electron PDI reduction and EPR spectroscopic analysis afforded a signal consistent with two weakly interacting S = 1/2 Mn centers. At ambient temperature in the absence of solvent, [(Ph2PEtPDI)Mn]2 has been found to catalyze the hydrosilylation of aldehydes at loadings as low as 0.005 mol % (0.01 mol % relative to Mn) with a maximum turnover frequency of 9,900 min-1 (4,950 min-1 per Mn). Moreover, the [(Ph2PEtPDI)Mn]2-catalyzed dihydrosilylation of formates has been found to proceed with turnover frequencies of up to 330 min-1 (165 min-1 relative to Mn). These metrics are comparable to those described for the leading Mn catalyst for this transformation, the propylene-bridged variant (Ph2PPrPDI)Mn; however, [(Ph2PEtPDI)Mn]2 is more easily inhibited by donor functionalities. Carbonyl and carboxylate hydrosilylation is believed to proceed through a modified Ojima mechanism following dimer dissociation.",

author = "Mukhopadhyay, {Tufan K.} and Chandrani Ghosh and Marco Flores and Groy, {Thomas L.} and Trovitch, {Ryan J.}",

note = "Funding Information: This material is based upon work supported by the National Science Foundation under Grant No. 1651686. Acknowledgement is also made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research. We acknowledge Dr. Brian R. Cherry for NMR assistance. Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",

year = "2017",

month = sep,

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doi = "10.1021/acs.organomet.7b00423",

language = "English (US)",

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T1 - Hydrosilylation of Aldehydes and Formates Using a Dimeric Manganese Precatalyst

AU - Mukhopadhyay, Tufan K.

AU - Ghosh, Chandrani

AU - Flores, Marco

AU - Groy, Thomas L.

AU - Trovitch, Ryan J.

N1 - Funding Information: This material is based upon work supported by the National Science Foundation under Grant No. 1651686. Acknowledgement is also made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research. We acknowledge Dr. Brian R. Cherry for NMR assistance. Publisher Copyright: © 2017 American Chemical Society.

PY - 2017/9/25

Y1 - 2017/9/25

N2 - The formally zero-valent Mn dimer [(Ph2PEtPDI)Mn]2 has been synthesized upon reducing (Ph2PEtPDI)MnCl2 with excess Na/Hg. Single crystal X-ray diffraction analysis has revealed that [(Ph2PEtPDI)Mn]2 possesses a η4-PDI chelate about each Mn center, as well as η2-imine coordination across the dimer. The chelate metrical parameters suggest single electron PDI reduction and EPR spectroscopic analysis afforded a signal consistent with two weakly interacting S = 1/2 Mn centers. At ambient temperature in the absence of solvent, [(Ph2PEtPDI)Mn]2 has been found to catalyze the hydrosilylation of aldehydes at loadings as low as 0.005 mol % (0.01 mol % relative to Mn) with a maximum turnover frequency of 9,900 min-1 (4,950 min-1 per Mn). Moreover, the [(Ph2PEtPDI)Mn]2-catalyzed dihydrosilylation of formates has been found to proceed with turnover frequencies of up to 330 min-1 (165 min-1 relative to Mn). These metrics are comparable to those described for the leading Mn catalyst for this transformation, the propylene-bridged variant (Ph2PPrPDI)Mn; however, [(Ph2PEtPDI)Mn]2 is more easily inhibited by donor functionalities. Carbonyl and carboxylate hydrosilylation is believed to proceed through a modified Ojima mechanism following dimer dissociation.

AB - The formally zero-valent Mn dimer [(Ph2PEtPDI)Mn]2 has been synthesized upon reducing (Ph2PEtPDI)MnCl2 with excess Na/Hg. Single crystal X-ray diffraction analysis has revealed that [(Ph2PEtPDI)Mn]2 possesses a η4-PDI chelate about each Mn center, as well as η2-imine coordination across the dimer. The chelate metrical parameters suggest single electron PDI reduction and EPR spectroscopic analysis afforded a signal consistent with two weakly interacting S = 1/2 Mn centers. At ambient temperature in the absence of solvent, [(Ph2PEtPDI)Mn]2 has been found to catalyze the hydrosilylation of aldehydes at loadings as low as 0.005 mol % (0.01 mol % relative to Mn) with a maximum turnover frequency of 9,900 min-1 (4,950 min-1 per Mn). Moreover, the [(Ph2PEtPDI)Mn]2-catalyzed dihydrosilylation of formates has been found to proceed with turnover frequencies of up to 330 min-1 (165 min-1 relative to Mn). These metrics are comparable to those described for the leading Mn catalyst for this transformation, the propylene-bridged variant (Ph2PPrPDI)Mn; however, [(Ph2PEtPDI)Mn]2 is more easily inhibited by donor functionalities. Carbonyl and carboxylate hydrosilylation is believed to proceed through a modified Ojima mechanism following dimer dissociation.

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U2 - 10.1021/acs.organomet.7b00423

DO - 10.1021/acs.organomet.7b00423

M3 - Article

AN - SCOPUS:85029943322

SN - 0276-7333

VL - 36

SP - 3477

EP - 3483

JO - Organometallics

JF - Organometallics

IS - 18

ER -

Hydrosilylation of Aldehydes and Formates Using a Dimeric Manganese Precatalyst

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CCDC 1552985: Experimental Crystal Structure Determination

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Hydrosilylation of Aldehydes and Formates Using a Dimeric Manganese Precatalyst

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CCDC 1552985: Experimental Crystal Structure Determination

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