dc.contributor.author |
Robertson, APM |
en |
dc.contributor.author |
Leitao, Erin |
en |
dc.contributor.author |
Jurca, T |
en |
dc.contributor.author |
Haddow, MF |
en |
dc.contributor.author |
Helten, H |
en |
dc.contributor.author |
Lloyd-Jones, GC |
en |
dc.contributor.author |
Manners, I |
en |
dc.date.accessioned |
2016-10-12T01:27:00Z |
en |
dc.date.issued |
2013-08-28 |
en |
dc.identifier.citation |
Journal of the American Chemical Society, 2013, 135 (34), 12670 - 12683 |
en |
dc.identifier.issn |
0002-7863 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/30716 |
en |
dc.description.abstract |
Linear diborazanes R3N-BH2-NR2-BH3 (R = alkyl or H) are often implicated as key intermediates in the dehydrocoupling/dehydrogenation of amine-boranes to form oligo- and polyaminoboranes. Here we report detailed studies of the reactivity of three related examples: Me3N-BH2-NMe2-BH3 (1), Me3N-BH2-NHMe-BH3 (2), and MeNH2-BH2-NHMe-BH3 (3). The mechanisms of the thermal and catalytic redistributions of 1 were investigated in depth using temporal-concentration studies, deuterium labeling, and DFT calculations. The results indicated that, although the products formed under both thermal and catalytic regimes are identical (Me3N·BH3 (8) and [Me2N-BH2]2 (9a)), the mechanisms of their formation differ significantly. The thermal pathway was found to involve the dissociation of the terminal amine to form [H2B(μ-H)(μ-NMe2)BH2] (5) and NMe3 as intermediates, with the former operating as a catalyst and accelerating the redistribution of 1. Intermediate 5 was then transformed to amine-borane 8 and the cyclic diborazane 9a by two different mechanisms. In contrast, under catalytic conditions (0.3-2 mol % IrH2POCOP (POCOP = κ(3)-1,3-(OPtBu2)2C6H3)), 8 was found to inhibit the redistribution of 1 by coordination to the Ir-center. Furthermore, the catalytic pathway involved direct formation of 8 and Me2N═BH2 (9b), which spontaneously dimerizes to give 9a, with the absence of 5 and BH3 as intermediates. The mechanisms elucidated for 1 are also likely to be applicable to other diborazanes, for example, 2 and 3, for which detailed mechanistic studies are impaired by complex post-redistribution chemistry. This includes both metal-free and metal-mediated oligomerization of MeNH═BH2 (10) to form oligoaminoborane [MeNH-BH2]x (11) or polyaminoborane [MeNH-BH2]n (16) following the initial redistribution reaction. |
en |
dc.description.uri |
https://www.ncbi.nlm.nih.gov/pubmed/23941398 |
en |
dc.format.medium |
Print-Electronic |
en |
dc.language |
English |
en |
dc.publisher |
American Chemical Society |
en |
dc.relation.ispartofseries |
Journal of the American Chemical Society |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from http://www.sherpa.ac.uk/romeo/issn/0002-7863/
http://pubs.acs.org/page/policy/articlesonrequest/index.html |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.title |
Mechanisms of the thermal and catalytic redistributions, oligomerizations, and polymerizations of linear diborazanes |
en |
dc.type |
Journal Article |
en |
dc.identifier.doi |
10.1021/ja404247r |
en |
pubs.issue |
34 |
en |
pubs.begin-page |
12670 |
en |
pubs.volume |
135 |
en |
dc.description.version |
VoR - Version of Record |
en |
dc.identifier.pmid |
23941398 |
en |
pubs.author-url |
http://pubs.acs.org/doi/abs/10.1021/ja404247r |
en |
pubs.end-page |
12683 |
en |
pubs.publication-status |
Published |
en |
dc.rights.accessrights |
http://purl.org/eprint/accessRights/RestrictedAccess |
en |
pubs.subtype |
Article |
en |
pubs.elements-id |
516196 |
en |
pubs.org-id |
Science |
en |
pubs.org-id |
Chemistry |
en |
dc.identifier.eissn |
1520-5126 |
en |
pubs.record-created-at-source-date |
2016-10-12 |
en |
pubs.online-publication-date |
2013-08-13 |
en |
pubs.dimensions-id |
23941398 |
en |