119137-06-3Relevant academic research and scientific papers
Photogeneration of Organic Bases from o-Nitrobenzyl-Derived Carbamates
Cameron, James F.,Fréchet, Jean M. J.
, p. 4303 - 4313 (2007/10/02)
The design of novel photoprecursors of organic bases and the steric and electronic factors that control their quantum-efficient transformation into free amines or diamines have been investigated. The basic design involves the protection of amines with photolabile [(o-nitrobenzyl)oxy]carbonyl groups or α-substituted analogues. The resulting protected amines owe their light sensitivity to the classical o-nitrobenzyl photorearrangement and cleanly liberate free amine in both the solid state and in solution upon irradiation with UV light below 400 nm. Several designs were explored in which the structure of the photoactive center was varied systematically to investigate the influence of various steric and electronic effects. In all cases, the practical potential of these photoactive carbamates as organic sources of photogenerated base was evaluated by product analysis of solution photolysates, by determination of their solid-state quantum efficiencies, and by measurement of their thermal properties. For example, the quantum efficiency of various carbamates for cyclohexylamine photogeneration at 254 nm ranged from 0.11 to 0.62 depending on both α-substituent and o-nitro substitution patterns, confirming the importance of both steric and electronic considerations. Similar results were obtained with other base photoprecursors and all showed good thermal stabilities.
PHOTOACTIVABLE FLUOROPHORES. 1. SYNTHESIS AND PHOTOACTIVATION OF o-NITROBENZYL-QUENCHED FLUORESCENT CARBAMATES
Cummings, Richard T,Krafft, Grant A.
, p. 65 - 68 (2007/10/02)
The synthesis and photoactivation of a new type of fluorescent probe, the photoactivable fluorophore (PAF) are described.The PAFs described in this paper consist of fluorescent aromatic amines coupled to substituted nitrobenzyl quenching chromophores via a carbamate linkage.Photoactivation occurs by an intramolecular photo-redox reaction, converting the o-nitrosobenzaldehyde hemiacetal which fragments with loss of CO2 to liberate the fluorescent amine.Photoactivation quantum yields also are reported.
