Nitrogen ionisation potential

The He(I) and He(n) photoelectron spectra of [UCp2(NEt2)2] have been recorded the first and second ionisation potentials were assumed as arising from electron loss from the 5f and a nitrogen-centred orbital, respectively. ... 

The results in Table III show the effect of various amines of different ionisation potential on the photopolymerisation of 2-hydroxyethylmethacrylate in nitrogen saturated water initiated by the benzophenone with the structure 2. As found earlier for the water soluble thioxanthones ( ), the percentage photoconversion decreases with increasing ionisation potential of the amine. In all of these experiments, oxygen had a strong quenching effect on the photopolymerisation. It would appear, therefore, that in aqueous media the photoinduced polymerisation of the acrylate monomer occurs solely via the lowest excited triplet state of the benzophenone molecule to form an exciplex with the amine co-synergist (Schemel ). 

Transient Absorption Maxima at 540 nm for Inititiator 1 (10 M) Compared with the Ionisation Potential of Various Amines (1.48 x lo M) in Nitrogen Saturated 2-Propanol... 

The hypothetical possibility of H replacement for a Ti atom in nitride has been also considered. In that case the energy of the impurity His level appears to be close to the atomic ionisation potential, and practically no hybridisation of H states with orbitals of the nearest nitrogen polyhedron (Ng) takes place. 

The mass spectra of pyrrolizidine alkaloids are very distinctive and often permit structural assignments to be made by comparison with mass spectra of alkaloids of known structure. The isomeric 1 -hydroxy-methylpyrrolizi-dines give a base peak at mje 83 (80) by typical fragmentation P to the nitrogen 4, 213). Characteristic ions at m/e 111 (81) and 80 (82) are observed for retronecine (18) and heliotridine (79), but measurement of the appearence and ionisation potentials has been used to distinguish between these epimers (224). Those alkaloids containing otonecine as base (Table 3 P) display characteristic fragment ions at m/e 168, 151, 150, 122, 110, and 94 (2,62). The A -oxides of pyrrolizidine alkaloids usually show the presence of ions at M-16, M-17, and M-18 (5). 

As GC techniques became more refined and were generally accepted, due to the superior separation and resolution potential of modern capillary columns, they took preference, especially in the analysis of PAH in car exhaust emissions and air particulates. In combination with an FID-detector, which, in contrast to the UV-detectors used frequently in HPLC analysis, has a nearly uniform response factor for hydrocarbons, or coupled to mass spectrometry, this technique must now be considered the method of first choice for a reliable and reproducible determination of PAH traces in a wide range of matrices. The introduction of more sensitive (photo-ionisation detector - PID) and specific detectors, such as the nitrogen-phosphorus (NPD)... 

A typical example is sulfacetamide (Fig. 22.40) which possesses a carbonyl substituent directly attached to the sulphonamido nitrogen. The reduced pKa (5.4) means it is 99.9% ionised at physiological pH. The potentially rapid excretion of sulfacetamide has limited its use to the treatment of ocular infections, such as conjunctivitis, caused by susceptible organisms. It is formulated as the sodium salt and used as a 10-30% w/v ophthalmic solution. 

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