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Modeling Aspects of Plasma-Enhanced Chemical Vapor Deposition of Carbon-Based Materials
Published in R. Mohan Sankaran, Plasma Processing of Nanomaterials, 2017
Uwe Kortshagen, Ming Mao, Erik Neyts, Annemie Bogaerts
First, the triangular shape of the cyclic radical renders this species structurally unstable. This can be easily seen by comparing cyclopropane to n-propane: in cyclopropane, the C-C bonds are about 32% weaker than in the linear isomer, due to a severe ring strain of 117 kJ/mol. In cyclic C3H, the effect is even more pronounced: the C-C bonds in cyclic C3H are about 50% weaker than in linear C3H. Hence, the release of this ring strain is a driving force for the radical to break up, enhancing drastically its reactivity. As a result, the molecule breaks up in more than 70% of the sticking events.
Spectroscopy
Published in Rui Yang, Analytical Methods for Polymer Characterization, 2018
In cyclic compounds, the ring strain increases with the reduction in ring size, resulting in the decrease in the stretching vibrational frequency of the internal double bonds in the ring, but the stretching vibrational frequency and intensity of the external double bond increase (Table 4.7).
Atmospheric degradation mechanisms and kinetics for OH-initiated oxidation of trans-β-ocimene
Published in Molecular Physics, 2023
IM40 can fragment into P21 + IM41 and CH3C(OH)(CH3)CHO(P23) + CH2CHC(CH3)CHCH2 (P24) via C6-C7 bond and C5-C6 bond cleavage transition state TS40-P21 and TS40-P23 with a barrier of 28.0 and 31.8 kJ/mol, respectively. IM41 can also convert into P20 via successive O2 addition and HO2 elimination processes. As shown in Figure 6, the resonance of the allylic radical formed in P24 leads to the formation of conjugated large π bond, which may be the reason of the large reaction heat of 25.7 kJ/mol for the production of P23 + P24. Moreover, the production of CH2CHC(CH3)CHCH2COC(OH)(CH3)CH3(P25) through interaction with O2 via TS40-HO2 has the lowest barrier of 20.5 kJ/mol, whereas the generation of P25 by C−H scission via TS40-H (85.8 kJ/mol) is accompanied by extremely high barrier and is of less importance in the atmosphere. As for the formation of IM43, the isomerisation barrier is 45.7 kJ/mol because of the reduced ring strain in seven-membered-ring transition state TS40-43.
Unprecedented cleavage of -N-N- bond of ligand and phenyl ring nitration during nitric oxide (NO) reactivity studies: new ruthenium nitrosyl complex and photoinduced liberation of NO
Published in Journal of Coordination Chemistry, 2022
Anand Ratnam, Sheela Kumari, Sain Singh, Kiran Mawai, Rajan Kumar, U. P. Singh, Kaushik Ghosh
Single-crystals of (1a) were grown on slow evaporation of the crude mixture of (1a) in dichloromethane and methanol. Reddish black square-shaped crystals of (1a) were obtained. The crystal structure of (1a) is shown in Figure 1 and the matrix parameters are depicted in Supplementary Table S1. In the molecular structure of (1a), two chloride ions, one pyridine N(1) and one N(2) constitute equatorial plane. Phosphine and NO remained in the axial positions, trans to each other. The metal center was found to be in a distorted octahedral fashion which is clearly indicated by the bond angles described below. N(1)–Ru(1)–Cl(2), N(2)–Ru(1)–Cl(1) and P(1)–Ru(1)–N(3) angles were 168.6(4)°, 159.6(3)° and 174.0(4)°, respectively, as reflected in solving the crystal structure. Ru − NNO distance (1.673(12) Å) was shorter than those reported in the literature [29–32]. This result was unusual; this observation might be due to the ring strain of the four-membered ring. The distance N–O (1.105(14) Å) was also shorter in comparison with the values given in the literature [29–32]. All these data, along with Ru–N–O angles (≈ 170.7(12)°), indicate the {Ru(II)–NO+}6 descriptions [18] of the {Ru–NO}6 moiety [18] (according to Enemark and Feltham Notation [33]). This description was also supported by IR spectroscopic data described in the next section. Some selected bond angles are shown in Table 1.
Theoretical investigation of the nitrogen-heterocyclic as π-linker in diphenylthienylamine-based dyes adsorbed on TiO2 nanotubes for DSSCs applications
Published in Molecular Physics, 2021
Ohoud S. Al-Qurashi, Nuha Wazzan
The bond angle between the two phenyl rings in DPTA shows a similar trend for what note in r1 and r2. That means the degree of planarity of DPTA unit becomes more planer when the nitrogen atoms are added or increased in π-linkers. On the other hand, the planarity between diphenylamin and thiophenyl (1) is in the range 144.45-160.73 o, which is less plane than that of 2 (169.81-177.79°). They also show a significant change with the adjustment in π-linkers. However, for all dyes are almost at the same plane that their values are very close to 180° and show insignificant effect by the adjustment in π-linkers. Generally, it will be expected that 5M-D0 and the six-membered rings dye have unique electronic properties due to ring strain.