6654-69-9Relevant articles and documents
Synthesis, characterization, and photoluminescent studies of three-coordinate Cu(i)-NHC complexes bearing unsymmetrically-substituted dipyridylamine ligands
Glinton, Kwame,Latifi, Reza,Cockrell, David S.,Bardeaux, Matthew,Nguyen, Bachkhoa,Tahsini, Laleh
, p. 22417 - 22427 (2019/07/31)
A series of heteroleptic three-coordinate Cu(i) complexes bearing monodentate N-heterocyclic carbene (NHC) ligands of the type 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) and 1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene (SIPr), and bidentate N-donor ligands of the type unsymmetrically-substituted dimethyl dipyridylamine (Me2Hdpa) and bis(mesityl)biazanaphthenequinone (mesBIAN) have been synthesized. The complexes [Cu(IPr)(3,4′-Me2Hdpa)]PF6, 1; [Cu(IPr)(3,5′-Me2Hdpa)]PF6, 2; [Cu(IPr)(3,6′-Me2Hdpa)]PF6, 3; [Cu(IPr)(mesBIAN)]PF6, 6; [Cu(SIPr)(3,4′-Me2Hdpa)]PF6, 7; [Cu(SIPr)(3,5′-Me2Hdpa)]PF6, 8; and [Cu(SIPr)(3,3′-Me2Hdpa)]PF6, 11 have been characterized by 1H and 13C NMR spectroscopies, elemental analysis, cyclic voltammetry, and photophysical studies in solid and solution phase. Single crystal X-ray structures were obtained for all complexes except 11. The crystallographic data reveal a mononuclear structure for all complexes with the copper atom ligated by one C and two N atoms. The UV-Vis absorption spectra of all dipyridylamine complexes in CH2Cl2 show a strong ligand-centered absorption band around 250 nm and a strong metal-to-ligand charge transfer (MLCT) band around 300 nm. When irradiated with UV light, the complexes exhibit strong emission maxima at 453-482 nm with photoluminescence quantum yields (PLQY) ranging from 0.21 to 0.87 in solid state. While the PLQY values are comparable to those of the symmetrical [Cu(IPr)(Me2Hdpa)]PF6 complexes, a stabilizing CH-π interaction has been reduced in the current systems. In particular, complex 3 lacks any strong CH-π interaction, but emits more efficiently than 1 and 2 wherein the interactions exist. Structural data analysis was performed to clarify the role of ligands' plane angle and the NH/CH?F interactions to the observed light interaction of unsymmetrical [Cu(NHC)(Me2Hdpa)]PF6 complexes. DFT calculations were performed to assist in the assignment of the electronic structure and excited state behavior of the complexes.
Mild and highly selective palladium-catalyzed monoarylation of ammonia enabled by the use of bulky biarylphosphine ligands and palladacycle precatalysts
Cheung, Chi Wai,Surry, David S.,Buchwald, Stephen L.
supporting information, p. 3734 - 3737 (2013/08/23)
A method for the Pd-catalyzed arylation of ammonia with a wide range of aryl and heteroaryl halides, including challenging five-membered heterocyclic substrates, is described. Excellent selectivity for monoarylation of ammonia to primary arylamines was achieved under mild conditions or at rt by the use of bulky biarylphosphine ligands (L6, L7, and L4) as well as their corresponding aminobiphenyl palladacycle precatalysts (3a, 3b, and 3c). As this process requires neither the use of a glovebox nor high pressures of ammonia, it should be widely applicable.
