| Autor: |
Evers-McGregor DA; Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02451, USA. thomasc@brandeis.edu., Bezpalko MW, Foxman BM, Thomas CM |
| Jazyk: |
angličtina |
| Zdroj: |
Dalton transactions (Cambridge, England : 2003) [Dalton Trans] 2016 Feb 07; Vol. 45 (5), pp. 1918-29. Date of Electronic Publication: 2015 Oct 14. |
| DOI: |
10.1039/c5dt03549j |
| Abstrakt: |
A chelating diphosphine ligand with a central N-heterocyclic phosphenium cation (NHP(+)) has been used to explore the coordination chemistry of NHPs with nickel. Treatment of the chlorophosphine precursor [PPP]Cl (1) with stoichiometric Ni(COD)2 affords (PPP)NiCl (8), which is best described as a Ni(II)/NHP(-) phosphido complex formed via oxidative addition of the P-Cl bond. In contrast, treating [PPP]Cl (1) with excess Ni(COD)2 results in a mixture of the trimetallic complex (PPP)2Ni3Cl2 (9) and the reduced NHP-bridged dimer [(PPP)Ni]2 (10). Compound 9 is found to be a Ni(II)Ni(II)Ni(0) complex in which the two NHP ligands act as bridging NHP(-) phosphidos, while complex 10 is a Ni(I)Ni(I) complex that is highly delocalized throughout the symmetric Ni2P2 core. In contrast, the reaction of [PPP][PF6] (11) with Ni(COD)2 affords an asymmetrically-bridged dication [(PPP)Ni]2[PF6]2 (12), which is found to contain two bridging NHP(+) cations bridging two Ni(0) centers. Comproportionation of 10 and 12 affords monocationic [(PPP)Ni]2[PF6] (13), completing the redox series. Nickel complexes 8-10 and 12 are largely similar to their Pd and Pt analogues, but a paramagnetic monocation such as 13 was not observed in the Pd and Pt case. Computational studies lend further insight into the electronic structure and bonding in complexes 8-10 and 12-13, and further support the potential redox non-innocent properties of NHP ligands. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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