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The Synthesis, X‐ray Structure Analysis, and Photophysical Characterization of 4‐[( E )‐2‐(4‐Carboxyphenyl)diazenyl]‐morpholine
Author(s) -
Johnson Mathew,
Galbreath Michael,
Fronczek Frank R.,
Isovitsch Ralph
Publication year - 2016
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.2494
Subject(s) - chemistry , morpholine , acetonitrile , delocalized electron , excited state , moiety , triazene , absorption (acoustics) , photochemistry , yield (engineering) , crystallography , medicinal chemistry , stereochemistry , organic chemistry , physics , materials science , nuclear physics , acoustics , metallurgy
4‐[( E )‐2‐(4‐Carboxyphenyl)diazenyl]‐morpholine ( 1 ) was prepared in 33% yield from a coupling reaction between morpholine and the diazonium ion formed from 4‐aminobenzoic acid. X‐ray structural analysis of 1 yielded two important insights into its structure: the geometry of the N―N double bond and the partial delocalization across the linear triazene moiety. The absorption spectra of 1 in dilute acetonitrile and 2‐methyltetrahydrofuran solutions both featured an intense ( ε ≈ 20,000 M −1 cm −1 ) band centered at 320–324 nm that was assigned as a mixture of π → π* and n → π* transitions. Emission was observed at 383 and 379 nm from dilute acetonitrile and 2‐methyltetrahydrofuran solutions of 1 , respectively, with the latter being red‐shifted to 439 nm at 77 K. Emission lifetime data for compound 1 provided evidence that the emission was a mixture of two excited state transitions.