Nitrogen incorporation

The tricyclic antidepressants (as well as, incidentally the antipsychotic drugs) are characterized by a three carbon chain between the ring system and the basic nitrogen. Incorporation of one of those carbon atoms into an additional fused ring is apparently consistent with activity. Preparation of this compound involves first homologation of the side chain. Thus the carboxylic acid 147 is first converted... 

Despite such limitations, plasma-deposited a-C(N) H films were found to be used in a number of applications. The stress reduction induced by nitrogen incorporation [12] and consequent adhesion improvement, allowed the development of a-C(N) H antireflective coatings for Ge-based infrared detectors [13]. It was also found that N can electronically dope a-C H films, and can strongly decrease the defect density, which gives prospects on its use as a semiconductor material [14]. Nitrogen incorporation was also found to decrease the threshold electric field in electron-field emission process [15], making possible the use of a-C(N) H films as an overcoat on emission tips in flat-panel display devices [16]. 

The previously discussed model suggests how realistic is the assumption of N2+ ion bombardment as the main driving force of growth kinetics and nitrogen incorporation in a-C(N) H film growth. 

On the other hand, films deposited by RFPECVD in CH2-N2 atmospheres showed a different behavior [54]. In this study, in addition to the reported enhanced maximum nitrogen incorporation of 22 at.% (see Section 2.3.1), an almost constant behavior of the Raman parameters was observed for nitrogen content up... 

Results on Raman spectroscopy thus show that nitrogen incorporation, at least for a large enough N content, results in the increase of the graphitic clusters. This is contrary to the formation of an amorphous solid related to the -C3N4 phase, which presumes sp -C hybridization and no clustering effects. 

The variation of the IR band intensities upon nitrogen incorporation for RF plasma-deposited a-C(N) H films is shown in Figure 26, as reported by Schwan et al. [53], As mentioned before, the intensity of the C—H stretching band decreases upon nitrogen incorporation, at the same time that an increase in the N —H stretching band intensity is observed. This suggests that hydrogen preferentially... 

It is important to stress that nitrogen incorporation in a-C H films always result, at least above a certain level, in a strong decrease in the tetrahedrally bonded carbon atom fraction. Raman spectroscopy also gives support to this observation, because the increase in the size of graphitic clusters only can proceed with also increasing sp fraction. 

Based on the IR spectroscopy, evidence that nitrogen incorporation into a-C H films may occur in the periphery of condensed aromatic rings [10], Mansur and... 

It will be interesting to discern if the preceding transformations are a consequence of electronic effects due solely to nitrogen incorporation, or if there is some influence of the growth process itself. Different theoretical approaches were used in the study of hydrogen-free carbon-nitrogen solids. 

Analysis of Table II shows discrepancies in the hardness and stress behavior of a-C(N) H films. Although all the works reported a clear stress reduction upon nitrogen incorporation, the hardness sometimes is quoted as almost constant, or on the other hand clearly decreasing. In addition to the possible effect of different deposition methods and conditions, it can be easily seen that the differences in hardness testing methods are the major source for discrepancies. Constant hardness behavior is only reported with the use microindentation methods, like Vickers and Knoop microhardness. On the other hand, the use of low-load nanoindentation methods always led to a nitrogen-induced decrease in hardness. This is basically the consequence of two factors. The first one is the higher penetration... 

Figure 35 shows the internal stress variation for a-C(N) H films deposited by RFPECVD under similar conditions, from different precursor mixtures (CH4-N2 [12], CH4-NH3 [56], and C2H2-N2 [54]). Despite all the nitrogen-free films showed about the same stress, the variations upon nitrogen incorporation are... 

Relatively few works considered the tribological properties of plasma-deposited a-C(N) H films. First, considering the coefficient of friction, nitrogen incorporation was not found to strongly modify it. Prioli et al. [93] studied the friction coefficient of a-C(N) H films against a Si3N4 probe in an atomic force microscope, in ambient air. Nitrogen incorporation up to about 10 at.% into the... 

Nitrogen incorporation is also found to increase the electrical conductivity of a-C(N) H films. Wood, Wyedeven. and Tsuji [57] reported a 4 orders of magnitude... 

II. amine nitrogen incorporated in the backbone of the polymer chain... 

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