Relaxation aromatic amines

Kim et al. observed a very fast ion pair formation (below their detection limit of about 1 ps) from transient absorption spectra of fullerenes in the presence of aromatic amines such as /V,/V-dimcthyl- or /V,/V-dicthyl-anilinc, corresponding to a rate > 1 X 1012 M-1 s-1. An explanation for such extremly fast electron transfer is most likely a ground-state complex of fullerene and amine. Excitation leads to the neutral aminc/ C 0 contact pair followed by electron transfer. The decay of the both transient absorption from Cfo and Qo/amine occurs with the same rate suggesting that charge recombination is the major nonradiative relaxation channel [138],... 

Amino-2,l-benzisothiazoles possess analgesic, antipyretic, tran-quilizing, and muscle-relaxant properties.100-103 The 3-methylamino derivative, in particular, displays potent gastric antisecretory activity.101,129 Diazotization of 3-amino-2,l-benzisothiazoles and coupling with tertiary aromatic amines yield a variety of azo dyes especially suitable for disperse dyeing of synthetic polymer fibers 116,117, n -121.13°. i 1... 

In Fig. 9 (a-c), TSD traces for some epoxy-aromatic amine networks in the glassy state are shown. It is clearly seen that in the glassy state there exist several different types, at least four, of TSD peaks (Fig. 9c). A special measurement has shown that all TSD peaks are a result of dipole relaxation but not of the migration of ions or heterocurrents. From Fig. 9 a and b it becomes clear that the yl peak belongs to unreacted epoxy groups the P peaks, undoubtedly, are related to some motions of aliphatic chains. The relaxation time as a function of temperature has been measured for two peaks — yt and p2 (dotted lines in Fig. 9c). Both peaks have been refined by... 

Various aromatic nitro drugs undergo enzymatic reduction to the corresponding aromatic amines. For example, the 7-nitro benzodiazepine derivatives clonazepam and nitrazepam are metabolized extensively to their respective 7-amino meubolitcs in humans. Thc skeletal muscle relaxant dantrolene (Dantrium) also reportedly undergoes reduction to aminodantrolene in humans. ... 

The relaxation times of ordinary organic molecules are close to a few picoseconds. Figure 1.7 gives relaxation frequency range for classical organic functions alkanes [33, 34], alcohols [35-39], alcohol ether [40], acid chlorides [41, 42], esters [43, 44], aliphatic [45-54] and aromatic halogens [55, 56], aliphatic [57, 58], aromatic ketones [59], nitriles [60], and aliphatic [61, 62] and aromatic amines [63]. 

Structural information on aromatic donor molecule binding was obtained initially by using H NMR relaxation measurements to give distances from the heme iron atom to protons of the bound molecule. For example, indole-3-propionic acid, a structural homologue of the plant hormone indole-3-acetic acid, was found to bind approximately 9-10 A from the heme iron atom and at a particular angle to the heme plane (234). The disadvantage of this method is that the orientation with respect to the polypeptide chain cannot be defined. Other donor molecules examined include 4-methylphenol (p-cresol) (235), 3-hydroxyphenol (resorcinol), 2-methoxy-4-methylphenol and benzhydroxamic acid (236), methyl 2-pyridyl sulfide and methylp-tolyl sulfide (237), and L-tyrosine and D-tyrosine (238). Distance constraints of between 8.4 and 12.0 A have been reported (235-238). Aromatic donor proton to heme iron distances of 6 A reported earlier for aminotriazole and 3-hydroxyphenol (resorcinol) are too short because of an inappropriate estimate of the molecular correlation time (239), a parameter required for the calculations. Distance information for a series of aromatic phenols and amines bound to Mn(III)-substituted HRP C has been published (240). 

---