Catalyst-Free Synthesis of Aryl Diamines via a Three-Step Reaction Process

Abstract

The formation of C-N bonds with aryl amines is one of the most widely studied reactions in organic chemistry. Despite this, it is still highly challenging, often requiring expensive, precious metal-based catalysts. Here we report an easy catalyst-free methodology for constructing C-N bonds. The method, which proceeds via the in situ formation of closed ring amidinium ions, allows the preparation of a series of symmetrical and/or unsymmetrical aryl diamines in notably high yields (82-98%) and purity and with a variety of different substituents. The methodology is shown successful for the preparation of aryl diamines having para- and/or meta-substituted carboxyl, nitro, bromo, methoxy, or methyl groups. This green synthetic pathway, which is catalyst free, requires only three steps, and proceeds without the need for purification. Further, it is a new sustainable, economically viable method to achieve an otherwise challenging bond formation.

Dirhodium(II,II)/NiO Photocathode for Photoelectrocatalytic Hydrogen Evolution with Red Light

“…All the synthetic procedures were performed under a N 2 atmosphere, but the samples were opened to air during the purification steps. The ligands p -diCOO t Bu-Form ( N , N ′-bis­( p -(ter-butyl)­phenyl)­formamidinate) and p -diCOOEt-Form were synthesized according to literature procedures and their 1 H NMR spectra are shown in Figures S1 and S2, respectively …”

“…The ligands p-diCOO t Bu-Form (N,N′-bis(p-(terbutyl)phenyl)formamidinate) and p-diCOOEt-Form were synthesized according to literature procedures and their 1 H NMR spectra are shown in Figures S1 and S2, respectively. 31 Rh 2 (p-diCOO t Bu-Form) 4 . Rh 2 (OAc) 4 (50 mg, 0.11 mmol) and 4 equiv of p-diCOO t Bu-Form were dissolved in 8 mL of chlorobenzene from a sealed bottle under N 2 , and the solution was refluxed for 2 days.…”

3D vs. turbostratic: controlling metal–organic framework dimensionality via N-heterocyclic carbene chemistry

“…From this ligand, a microporous MOF, Cu-Sp5, was subsequently synthesized. 24,25 While the material exhibits an interesting combination of open metal sites and charged ion pairs, two structural features that lead to a remarkable CO 2 /N 2 selectivity for potential gas separations, the framework also featured interpenetration. This structural feature leads to a small pore size, which is not optimal to access the reactive C 2 site on the imidazole ligand, as it is thought to impede the formation of an NHC or NHC-derived metal complex inside the MOF pore space.…”