- Cu(I) complexes of pincer pyridine-based N-heterocyclic carbenes with small wingtip substituents: Synthesis and structural and spectroscopic studies
-
Six new Cu(I) complexes with pincer N-heterocyclic carbene (NHC) ligands of the type 2,6-bis(3-alkylimidazol-2-ylidene)pyridine, I(R)CNC, and 2,6-bis(3-alkylimidazol-2-ylidene)methylpyridine, I(R)C^N^C, where R = Me, Et, and iPr have been synthesized using Cu precursors and bis(imidazolium) salts. All of these compounds, namely, [Cu2(IMeCNC)2](PF6)2, 1; [Cu2(IEtCNC)2](PF6)2, 2; [Cu2(IiPrCNC)2](PF6)2, 3; [Cu(IMeC^N^C)](PF6), 4; [Cu(IEtC^N^C)](PF6), 5; and [Cu(IiPrC^N^C)](PF6), 6, have been characterized by 1H and 13C NMR spectroscopies, elemental analysis, solution conductivity, and electrochemical studies. Single crystal X-ray structures were obtained for all complexes except 1. The crystallographic data reveal a binuclear structure containing two Cu atoms at a close distance, 2.622-2.811 ? for all the complexes except 5, which shows a unique mononuclear structure. Spatial syn arrangement of ethyl groups and extensive π-π stacking in the solid state accounts for the mononuclear structure of complex 5. A pseudolinear coordination geometry about metal centers consisting of two Cu-carbene bonds, as well as weak Cu-pyridine interactions, exist among all the complexes independent of their ligand. Solution-state conductivity data reveal a dominant 1:2 electrolyte behavior for 1-3 but 1:1 electrolyte for 4-6, consistent with the sustainable binuclear structure in solutions of Cu(I)-I(R)CNC complexes. Cyclic voltammetry and differential pulse voltammetry studies reveal an irreversible and two quasi-reversible peaks for the one-electron oxidation of solvent-bound and solvent-free binuclear and mononuclear Cu-NHC species in complexes 1-3. In contrast, the reversible Cu(II)/Cu(I) couples of 4-6 at potentials close to that of complexes with tripodal polydentate NHC scaffolds indicate the electronic and structural flexibility of I(R)C^N^C ligands to accommodate both Cu(I) and Cu(II) ions.
- Domyati, Doaa,Hope, Sydney L.,Latifi, Reza,Hearns, Micah D.,Tahsini, Laleh
-
-
Read Online
- A nickel complex with a biscarbene pincer-type ligand shows high electrocatalytic reduction of CO2 over H2O
-
We report a planar nickel complex coordinated with a pincer-type carbene-pyridine-carbene ligand which exhibits high selectivity for electrocatalytic CO2 reduction in the presence of H2O.
- Sheng, Meili,Jiang, Nan,Gustafson, Samantha,You, Bo,Ess, Daniel H.,Sun, Yujie
-
-
Read Online
- Orchestrated catalytic double rollover annulation: Rapid access to N-enriched cationic and neutral PAHs
-
Disclosed herein is a rhodium(iii)-catalyzed novel one-step back-To-back double rollover annulation on pyridine and pyrazine backbones leading to a structurally and optoelectronically diverse class of nicely decorated multi-ring-fused, extensively π-conjugated, N-enriched PAH molecules by virtue of orchestrated quadruple C-H activation events. Selected N-PAHs have been utilized as potential mitochondria and lysosome markers.
- Karak, Pirudhan,Dutta, Champak,Dutta, Tanoy,Koner, Apurba Lal,Choudhury, Joyanta
-
supporting information
p. 6791 - 6794
(2019/06/17)
-
- A Pd complex of a tridentate pincer CNC bis-carbene ligand as a robust homogenous Heck catalyst
-
The bis-carbene precursor, 1, gives a thermally very robust Pd(II) catalyst for Heck coupling that maintains activity even in boiling diethylacetamide (bp 184°C) in air.
- Peris,Loch,Mata,Crabtree
-
p. 201 - 202
(2007/10/03)
-
- The first dicarbene double helical mercury complex
-
An intermediate and a double helical complex of mercury with a new tridentate carbene based ligand were obtained and structurally characterized. The Royal Society of Chemistry 2000.
- Chen, Jack C. C.,Lin, Ivan J. B.
-
p. 839 - 840
(2007/10/03)
-