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Synthesis and Characterization of a Family of POCOP Pincer Complexes with Nickel: Reactivity Towards CO2 and Phenylacetylene.

Jonasson, Klara LU and Wendt, Ola LU (2014) In Chemistry: A European Journal 20(37). p.11894-11902
Abstract
A cyclohexyl-based POC sp 3OP pincer ligand (POC sp 3OP=cis-1,3-bis(di-tert-butylphosphinito)cyclohexyl) cyclometalates with nickel to generate a series of new POC sp 3OP-supported Ni(II) complexes, including the halide, hydride, methyl, and phenyl species. trans-[NiCl{cis-1,3-bis(di-tert-butylphosphinito)cyclohexane}], [(POC sp 3OP)NiCl] (1 a) and the analogous bromide complex (1 b) were synthesized and fully characterized by NMR spectroscopy and X-ray crystallography. Cyclic voltammetry measurements of 1 a and 1 b alongside their bis(phosphine) analogues [(PC sp 3P)NiCl] (2 a) and [(PC sp 3P)NiCl] (2 a) (PC sp 3P=cis-1,3-bis(di-tert-butylphosphino)cyclohexyl) indicate a reduced electron density at the metal center upon introducing... (More)
A cyclohexyl-based POC sp 3OP pincer ligand (POC sp 3OP=cis-1,3-bis(di-tert-butylphosphinito)cyclohexyl) cyclometalates with nickel to generate a series of new POC sp 3OP-supported Ni(II) complexes, including the halide, hydride, methyl, and phenyl species. trans-[NiCl{cis-1,3-bis(di-tert-butylphosphinito)cyclohexane}], [(POC sp 3OP)NiCl] (1 a) and the analogous bromide complex (1 b) were synthesized and fully characterized by NMR spectroscopy and X-ray crystallography. Cyclic voltammetry measurements of 1 a and 1 b alongside their bis(phosphine) analogues [(PC sp 3P)NiCl] (2 a) and [(PC sp 3P)NiCl] (2 a) (PC sp 3P=cis-1,3-bis(di-tert-butylphosphino)cyclohexyl) indicate a reduced electron density at the metal center upon introducing electron-withdrawing oxygen atoms in the pincer arms. The methyl [(POC sp 3OP)NiMe] (3) and phenyl [(POC sp 3OP)NiPh] (4) complexes were formed from 1 a by reaction with the corresponding organolithium reagents. 1 a also reacts with LiAlH4 to give the hydride complex [(POC sp 3OP)NiH] (5). The methyl complex 3 reacts with phenyl acetylene to give the acetylide complex [(POC sp 3OP)NiCCPh] (6). The reactivity of compounds 3-5 towards CO2 was studied. The hydride complex 5 and the methyl complex 3 both underwent CO2 insertion to form the formate species [(POC sp 3OP)NiOCOH] (7) and acetate species [(POC sp 3OP)NiOCOCH3 ] (8), respectively, although with a higher barrier of insertion in the latter case. Compound 4 was unreactive towards CO2 even at elevated temperatures. Complexes 3-8 were all characterized by NMR spectroscopy and X-ray crystallography. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Chemistry: A European Journal
volume
20
issue
37
pages
11894 - 11902
publisher
John Wiley & Sons
external identifiers
  • pmid:25080339
  • wos:000341630500038
  • scopus:84906949382
ISSN
1521-3765
DOI
10.1002/chem.201403246
language
English
LU publication?
yes
id
35a81ca8-cfec-4103-8378-f8bc0cbd8f07 (old id 4615795)
date added to LUP
2014-09-12 16:44:40
date last changed
2017-10-08 03:05:18
@article{35a81ca8-cfec-4103-8378-f8bc0cbd8f07,
  abstract     = {A cyclohexyl-based POC sp 3OP pincer ligand (POC sp 3OP=cis-1,3-bis(di-tert-butylphosphinito)cyclohexyl) cyclometalates with nickel to generate a series of new POC sp 3OP-supported Ni(II) complexes, including the halide, hydride, methyl, and phenyl species. trans-[NiCl{cis-1,3-bis(di-tert-butylphosphinito)cyclohexane}], [(POC sp 3OP)NiCl] (1 a) and the analogous bromide complex (1 b) were synthesized and fully characterized by NMR spectroscopy and X-ray crystallography. Cyclic voltammetry measurements of 1 a and 1 b alongside their bis(phosphine) analogues [(PC sp 3P)NiCl] (2 a) and [(PC sp 3P)NiCl] (2 a) (PC sp 3P=cis-1,3-bis(di-tert-butylphosphino)cyclohexyl) indicate a reduced electron density at the metal center upon introducing electron-withdrawing oxygen atoms in the pincer arms. The methyl [(POC sp 3OP)NiMe] (3) and phenyl [(POC sp 3OP)NiPh] (4) complexes were formed from 1 a by reaction with the corresponding organolithium reagents. 1 a also reacts with LiAlH4 to give the hydride complex [(POC sp 3OP)NiH] (5). The methyl complex 3 reacts with phenyl acetylene to give the acetylide complex [(POC sp 3OP)NiCCPh] (6). The reactivity of compounds 3-5 towards CO2 was studied. The hydride complex 5 and the methyl complex 3 both underwent CO2 insertion to form the formate species [(POC sp 3OP)NiOCOH] (7) and acetate species [(POC sp 3OP)NiOCOCH3 ] (8), respectively, although with a higher barrier of insertion in the latter case. Compound 4 was unreactive towards CO2 even at elevated temperatures. Complexes 3-8 were all characterized by NMR spectroscopy and X-ray crystallography.},
  author       = {Jonasson, Klara and Wendt, Ola},
  issn         = {1521-3765},
  language     = {eng},
  number       = {37},
  pages        = {11894--11902},
  publisher    = {John Wiley & Sons},
  series       = {Chemistry: A European Journal},
  title        = {Synthesis and Characterization of a Family of POCOP Pincer Complexes with Nickel: Reactivity Towards CO2 and Phenylacetylene.},
  url          = {http://dx.doi.org/10.1002/chem.201403246},
  volume       = {20},
  year         = {2014},
}