Catalytic dehydrocoupling of Amine-Boranes Using Cationic Zirconium(IV)-Phosphine Frustrated Lewis Pairs

Owen J Metters; Stephanie R Flynn; Christiana Dowds; Hazel A Sparkes; Ian Manners; Duncan F Wass

doi:10.1021/acscatal.6b02211

Catalytic dehydrocoupling of Amine-Boranes Using Cationic Zirconium(IV)-Phosphine Frustrated Lewis Pairs

Owen J Metters, Stephanie R Flynn, Christiana Dowds, Hazel A Sparkes, Ian Manners, Duncan F Wass

Research output: Contribution to journal › Article (Academic Journal) › peer-review

35 Citations (Scopus)

551 Downloads (Pure)

Abstract

A series of novel, intramolecular Zr(IV)/P frustrated Lewis pairs (FLPs) based on cationic zirconocene fragments with a variety of ancillary cyclopentadienyl and 2-
phosphinoaryloxide (−O(C6H4)PR2, R = tBu and 3,5-CF3- (C6H3)) ligands are reported and their activity as catalysts for the dehydrocoupling of dimethylamine−borane (Me2NH·BH3) assessed. The FLP system [(C9H7)2ZrO(C6H4)PtBu2]-[B(C6F5)4] is shown to give unprecedented turnover
frequencies (TOF) for a catalyst based on a group 4 metal (TOF ≥ 600 h−1), while also proving to be the most efficient FLP catalyst reported to date. The mechanism of this reaction has been probed using analogous intermolecular Zr(IV)/P FLPs, permitting deconvolution of the reactions taking place at both the Lewis acidic and basic sites. Elucidation of this mechanism revealed an interesting cooperative two-cycle process where one cycle is FLP mediated and the other, a redistribution of a linear diborazane intermediate, relies solely on the presence of a Zr(IV) Lewis acid.

Original language	English
Pages (from-to)	6601-6611
Number of pages	11
Journal	ACS Catalysis
Volume	6
Early online date	9 Aug 2016
DOIs	https://doi.org/10.1021/acscatal.6b02211
Publication status	Published - 7 Oct 2016

Keywords

amine−borane
dehydrocoupling
FLP
frustrated Lewis pairs
zirconocenes

Access to Document

10.1021/acscatal.6b02211

Full-text PDF (accepted author manuscript)
This is the author accepted manuscript (AAM). The final published version (version of record) is available online via ACS at http://pubs.acs.org/doi/abs/10.1021/acscatal.6b02211. Please refer to any applicable terms of use of the publisher.
Accepted author manuscript, 1.12 MBLicence: CC BY-NC
Supplementary information PDF
This is the author accepted manuscript (AAM). The final published version (version of record) is available online via ACS at http://pubs.acs.org/doi/abs/10.1021/acscatal.6b02211. Please refer to any applicable terms of use of the publisher.
Accepted author manuscript, 1.79 MB

Handle.net

Persistent link

3-month Core Capability for Chemistry Research
Crosby, J. (Principal Investigator)
1/01/13 → 1/04/13
Project: Research

Cite this

@article{3d6d7c7c11044f6b8aa787fad6a6a266,

title = "Catalytic dehydrocoupling of Amine-Boranes Using Cationic Zirconium(IV)-Phosphine Frustrated Lewis Pairs",

abstract = "A series of novel, intramolecular Zr(IV)/P frustrated Lewis pairs (FLPs) based on cationic zirconocene fragments with a variety of ancillary cyclopentadienyl and 2-phosphinoaryloxide (−O(C6H4)PR2, R = tBu and 3,5-CF3- (C6H3)) ligands are reported and their activity as catalysts for the dehydrocoupling of dimethylamine−borane (Me2NH·BH3) assessed. The FLP system [(C9H7)2ZrO(C6H4)PtBu2]-[B(C6F5)4] is shown to give unprecedented turnoverfrequencies (TOF) for a catalyst based on a group 4 metal (TOF ≥ 600 h−1), while also proving to be the most efficient FLP catalyst reported to date. The mechanism of this reaction has been probed using analogous intermolecular Zr(IV)/P FLPs, permitting deconvolution of the reactions taking place at both the Lewis acidic and basic sites. Elucidation of this mechanism revealed an interesting cooperative two-cycle process where one cycle is FLP mediated and the other, a redistribution of a linear diborazane intermediate, relies solely on the presence of a Zr(IV) Lewis acid.",

keywords = "amine−borane, dehydrocoupling, FLP, frustrated Lewis pairs, zirconocenes",

author = "Metters, {Owen J} and Flynn, {Stephanie R} and Christiana Dowds and Sparkes, {Hazel A} and Ian Manners and Wass, {Duncan F}",

year = "2016",

month = oct,

day = "7",

doi = "10.1021/acscatal.6b02211",

language = "English",

volume = "6",

pages = "6601--6611",

journal = "ACS Catalysis",

issn = "2155-5435",

publisher = "American Chemical Society",

}

TY - JOUR

T1 - Catalytic dehydrocoupling of Amine-Boranes Using Cationic Zirconium(IV)-Phosphine Frustrated Lewis Pairs

AU - Metters, Owen J

AU - Flynn, Stephanie R

AU - Dowds, Christiana

AU - Sparkes, Hazel A

AU - Manners, Ian

AU - Wass, Duncan F

PY - 2016/10/7

Y1 - 2016/10/7

N2 - A series of novel, intramolecular Zr(IV)/P frustrated Lewis pairs (FLPs) based on cationic zirconocene fragments with a variety of ancillary cyclopentadienyl and 2-phosphinoaryloxide (−O(C6H4)PR2, R = tBu and 3,5-CF3- (C6H3)) ligands are reported and their activity as catalysts for the dehydrocoupling of dimethylamine−borane (Me2NH·BH3) assessed. The FLP system [(C9H7)2ZrO(C6H4)PtBu2]-[B(C6F5)4] is shown to give unprecedented turnoverfrequencies (TOF) for a catalyst based on a group 4 metal (TOF ≥ 600 h−1), while also proving to be the most efficient FLP catalyst reported to date. The mechanism of this reaction has been probed using analogous intermolecular Zr(IV)/P FLPs, permitting deconvolution of the reactions taking place at both the Lewis acidic and basic sites. Elucidation of this mechanism revealed an interesting cooperative two-cycle process where one cycle is FLP mediated and the other, a redistribution of a linear diborazane intermediate, relies solely on the presence of a Zr(IV) Lewis acid.

AB - A series of novel, intramolecular Zr(IV)/P frustrated Lewis pairs (FLPs) based on cationic zirconocene fragments with a variety of ancillary cyclopentadienyl and 2-phosphinoaryloxide (−O(C6H4)PR2, R = tBu and 3,5-CF3- (C6H3)) ligands are reported and their activity as catalysts for the dehydrocoupling of dimethylamine−borane (Me2NH·BH3) assessed. The FLP system [(C9H7)2ZrO(C6H4)PtBu2]-[B(C6F5)4] is shown to give unprecedented turnoverfrequencies (TOF) for a catalyst based on a group 4 metal (TOF ≥ 600 h−1), while also proving to be the most efficient FLP catalyst reported to date. The mechanism of this reaction has been probed using analogous intermolecular Zr(IV)/P FLPs, permitting deconvolution of the reactions taking place at both the Lewis acidic and basic sites. Elucidation of this mechanism revealed an interesting cooperative two-cycle process where one cycle is FLP mediated and the other, a redistribution of a linear diborazane intermediate, relies solely on the presence of a Zr(IV) Lewis acid.

KW - amine−borane

KW - dehydrocoupling

KW - FLP

KW - frustrated Lewis pairs

KW - zirconocenes

U2 - 10.1021/acscatal.6b02211

DO - 10.1021/acscatal.6b02211

M3 - Article (Academic Journal)

SN - 2155-5435

VL - 6

SP - 6601

EP - 6611

JO - ACS Catalysis

JF - ACS Catalysis

ER -

Catalytic dehydrocoupling of Amine-Boranes Using Cationic Zirconium(IV)-Phosphine Frustrated Lewis Pairs

Abstract

Keywords

Access to Document

Handle.net

Fingerprint

Projects

3-month Core Capability for Chemistry Research

Cite this