Thermal decomposition of mono- and bimetallic magnesium amidoborane complexes
Spielmann J, Piesik DFJ, Harder S (2010)
Publication Type: Journal article, Original article
Publication year: 2010
Journal
Original Authors: Spielmann J., Piesik D.E.-J., Harder S.
Publisher: Wiley-VCH Verlag
Book Volume: 16
Pages Range: 8307-8318
Journal Issue: 28
Abstract
Complexes of the type [(DIPPnacnac)MgNH(R)BH ] have been prepared (DIPPnacnac=CH{(CMe)(2,6-iPr C H N)} ). The following substituents R have been used: H, Me, iPr, DIPP (DIPP = 2,6-diisopropylphenyl). Complexes [(DIPPnacnac)MgNH BH ]·THF, [{(DIPPnacnac)MgNH(iPr)BH } ] and [(DIPPnacnac)MgNH(DIPP)BH ] were structurally characterised. The Mg amidoborane complexes decompose at a significantly higher temperature (90-110°C) than the corresponding Ca amidoborane complexes (20100°C). The complexes with the smaller R substituents (H, Me) gave a mixture of decomposition products of which one could be structurally characterised as [{(DIPPnacnac)Mg} (H BNMe-BH-NMe)·THF. [{(DIPPnacnac)MgNH(iPr)BH } ] cleanly decomposed to [(DIPPnacnac)MgH], which was characterised as a dimeric THF adduct. The amidoborane complex with the larger DIPP-substituent decomposed into a borylamide complex [(DIPPnacnac)MgN (DIPP)BH ], which was structurally characterised as its THF adduct. Bimetallic Mg amidoborane complexes decompose at lower temperatures (60-90°C) and show a different decomposition pathway. The dinuclear Mg amidoborane complexes presented here are based on DIPPnacnac units that are either directly coupled through N-N bonding (abbreviated NN) or through a 2,6-pyridylene bridge (abbreviated PYR). Crystal structures of [PYR-{Mg(nBu)} ], [PYR-(MgNH(iPr)BH } ], [NN{MgNH(iPr)BH } ]·THF and the decomposition products [PYR-Mg (iPrN-BH-iPrN-BH )] and [NN-Mg (iPrNBH-iPrN-BH )]·THF are presented. The following conclusions can be drawn from these studies: i)The first step in the decomposition of a metal amidoborane complex is β-hydride elimination, which results in formation of a metal hydride complex and R(H)N=BH , ii) depending on the nature of the metal, the metal hydride is either stable and can be isolated or it reacts further, iii) amidoborane anions with small R substituents decompose into the dianionic species (RN-BHRN-BH ) , whereas large substituents result in formation of the borylamide RN=BH and iv) enforced proximity of two Mg amidoborane units results in decomposition at a significantly lower temperature and cleanly follows the BNBN pathway. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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APA:
Spielmann, J., Piesik, D.F.-J., & Harder, S. (2010). Thermal decomposition of mono- and bimetallic magnesium amidoborane complexes. Chemistry - A European Journal, 16(28), 8307-8318. https://doi.org/10.1002/chem.201000028
MLA:
Spielmann, Jan, Dirk F. -J. Piesik, and Sjoerd Harder. "Thermal decomposition of mono- and bimetallic magnesium amidoborane complexes." Chemistry - A European Journal 16.28 (2010): 8307-8318.
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