Rh(III)-Catalyzed ortho-C–H Amidation of Naphthalene and Perylene Monoimides

Abstract

The direct formation of a C–N bond at the ortho-position of naphthalene monoimides (NMI) and perylene monoimides (PMI) is reported herein using dioxazolones as the amide source. This method affords direct access to ortho-amino NMI and PMI through an amidation and deprotection sequence. One-pot telescopic bay-bromination of ortho-amino PMIs was also achieved. The ortho-amidated NMIs and PMIs, accessed by the current methodology, show significant red shifts in their absorption and fluorescence spectra compared with the NMI and PMI alone. An improvement in the quantum yield and fluorescence lifetime was observed by the incorporation of pivalamide groups at the ortho-positions of NMI and PMI.

Mechanistic Investigation of Oxidative Methanol Carbonylation with Mixed Cu(I)/Cu(II)–N-Methylimidazole Catalysts

“…The samples were prepared into dilute solutions with a concentration of 1.0 × 10 –5 mol·L –1 for testing. As shown in Figure a, the absorption bands between 270 and 320 nm could be assigned to imidazole rings in catalysts, as well as the NMI ligand . Compared to the NMI ligand, the obvious absorption bands over copper complex catalysts were observed in the wavelength ranges of 340–440 and 550–850 nm, which could be attributed to the coordination between the copper ion and the NMI ligand .…”

“…As shown in Figure 2a, the absorption bands between 270 and 320 nm could be assigned to imidazole rings in catalysts, as well as the NMI ligand. 28 Compared to the NMI ligand, the obvious absorption bands over copper complex catalysts were observed in the wavelength ranges of 340−440 and 550−850 nm, which could be attributed to the coordination between the copper ion and the NMI ligand. 29 As shown in the normalized absorption spectra (Figure 2b,c), this coordination also leads to a red shift of the absorption wavelength.…”

Transition-Metal-Catalyzed C–H Activation Reactions for the Creation and Modification of Organic Fluorophores

“…183,184 In the context of heteroatom-directed C−H activation/functionalization reactions, the cyclic imide group(s) of perylene imides, behave as a weak-coordinating group to weakly bind a transition metal and activate the proximal ortho-C−H bond for efficiently reacting with various coupling partners to deliver the ortho-functionalized perylene imide molecules (Scheme 70). [185][186][187][188][189][190][191][192][193][194][195][196][197][198][199][200][201][202][203][204] This C−H activation/functionalization strategy modifies the optical and physical properties of these rylene imides. Thereafter, in 2010, Marks and Wasielewski synthesized the ortho-alkylated perylene diimide, perylene monoimide, naphthalene diimide and naphthalene monoimide derivatives and investigated their photophysics and redox properties (Scheme 71).…”

“…To establish a C−N bond formation at the ortho-position, Kapur and co-workers devised a method for amidation of 1,8-naphthalimides and perylene monoimide dyes employing rhodium(III) catalysis (Scheme 79). 204 In this method, they explored a range of suitable substrates and broadened the synthetic applicability of amidated NMIs and PMIs. They also achieved the removal of pivaloyl groups in a single step by employing hydrobromic acid, allowing the access to ortho-amino NMIs and PMIs in a step-economical fashion (Scheme 80A).…”