Insights into dynamic covalent chemistry at surfaces

Abstract

The potential of surface confined self-assembly to influence the chemical equilibrium of Schiff base formation and bias the yield and distribution of reaction products is explored.

One‐Pot Generation of Benzynes from Phenols: Formation of Primary Anilines by the Deoxyamination of Phenols

“…The crude product, in which 3,5-dimethoxy-2-(trimethylsilyl)aniline, 4,6-dimethoxy-2-(trimethylsilyl)aniline, and 2,4-dimethoxyaniline were not detected by 300 MHz 1 HNMR analysis, was purified by column chromatography on silica gel (hexane/EtOAc = 2:1) to provide the title compound 2-(Trimethylsilyl)aniline (5 a) (Table 2, entry 1): [32] By following the General Procedure, am ixture of KHMDS (0.60 mL, 0.60 mmol), NfF (43 mL, 0.24 mmol), tris(trimethylsilyl)amine (93 mg, 0.40 mmol) and phenol (2b)( 19 mg, 0.20 mmol) was stirred in THF (2.0 mL) for 5h at 60 8C. The crude product, in which aniline was not detected by 300 MHz 1 HNMR analysis, was purified by column chromatography on silica gel (hexane/EtOAc = 16:1) to provide the title compound 3,5-Di-tert-butylaniline (3 b) ( Table 2, entry 2a nd Table 3, entry 5): [33] For Ta ble 2, entry 2: By following the General Procedure, am ixture of KHMDS (0.60 mL, 0.60 mmol), NfF (43 mL, 0.24 mmol), tris(trimethylsilyl)amine (93 mg, 0.40 mmol) and 3,5-ditert-butylphenol (2c)( 41 mg, 0.20 mmol) was stirred in THF (2.0 mL) for 5h at 60 8C. The crude product in which 3,5-di-tertbutyl-2-(trimethylsilyl)aniline, 2,4-di-tert-butyl-6-(trimethylsilyl)aniline, and 2,4-di-tert-butylaniline were not detected by 400 MHz 1 HNMR analysis, was purified by column chromatography on silica gel (hexane/EtOAc = 2:1) to provide the title compound 3b (32 mg, 78 %) as abrown oil.…”

Imine‐Based Architectures at Surfaces and Interfaces: From Self‐Assembly to Dynamic Covalent Chemistry in 2D

“…Within the scope of that work, we reported for the first time on the STM studies on the constitutionalc ovalent (reversible) dynamic processes of bis-transimination, that is,d iamine exchange on the bis-imines, as illustrated in Figure4.T of ully explore the reversible nature of imine bonds and to gain insight into the bis-transimination processes of bis-iminem olecules, successive in situ imination/bis-transimination cycles were performed. [75] These amino compounds werec hosen as ar esult of the differences in affinity,t hat is, adsorption energy,o fr eagents and products to HOPG,a morphous carbon,a nd silica. Upon subsequent addition of as olution of 25,t he 1 2 24 monolayer was transformed into a 1 2 The on-surface condensation of trialdehyde 16 with 5-aminoisophthalic acid (22)a tt he solid-liquid interface was investigated by Li and co-workers [74] and is shown in Figure 5.…”

“…The structuralt ransformation of trialdehyde Recently,P las and co-workers studied condensation reactions between aldehyde 6 with amine derivatives 19 and 20. [75] These amino compounds werec hosen as ar esult of the differences in affinity,t hat is, adsorption energy,o fr eagents and products to HOPG,a morphous carbon,a nd silica. Am ixture of reagents 6, 19,a nd 20 in ar atio of 1:2:2i n1 -phenyloctane was drop-casto nto solid substrates.…”

“…Reproduced from Ref [75]. d) Chemical structures of products formed during the condensation reaction of 6, 19,and 20 at the liquid-solid interface on the surface of HOPG.…”

“…d) Chemical structures of products formed during the condensation reaction of 6, 19,and 20 at the liquid-solid interface on the surface of HOPG. Reproduced from Ref [75]. with permission from the Royal SocietyofC hemistry.…”