Nanotubes molecular structure

It is to be noted that the QSPR/QSAR analysis of nanosubstances based on elucidation of molecular structure by the molecular graph is ambiguous due to a large number of atoms involved in these molecular systems. Under such circumstances the chiral vector can be used as elucidation of structure of the carbon nanotubes (Toropov et al., 2007c). The SMILES-like representation information for nanomaterials is also able to provide reasonable good predictive models (Toropov and Leszczynski, 2006a). 

So far, direct evidence of C60 hydrogenation inside of nanotubes from HRTEM imaging is absent. It is required as a decisive demonstration of possibility for hydrogen to penetrate inside of peapods but could possibly be challenging experimentally. Chemical reaction within nanospace of carbon nanotubes is possibly only first example of interesting nanoscale chemistry and fullerene hydrogenation in other exotic environments will possibly be successfully demonstrated in future. It is quite likely that hydrogenation in confined space results in formation of fulleranes with different molecular structures. 

Okamoto, H., Takeda, K., and Shiraishi, K. (2001). First-principles study of the electronic and molecular structure of protein nanotubes. Phys. Rev. B, 64(11) 115425/1-115425/17. 

Tire second half of the book concerns measurements and particular molecular structures. After a general overview, this section concentrates on specifics, ranging from complex molecules like catanenes and rotaxanes through ruthenium complexes and organometallics. More materials-oriented contributions on carbon nanotubes. 

If, instead of lipid membranes, simple peptides with hydrophobic tails and hydrophilic heads (made up of merely a combination of these robust, abiotically synthesized amino acids) could self-assemble into nanotubes or vesicles, they would have the potential to provide a primitive enclosure for the earliest RNA-based (Beaudry and Joyce, 1992 Wilson and Szostak, 1995) or peptide enzymes and other primitive molecular structures with a variety of functions. 

Wang, R., Zhang, D., Sun, W., Han, Z. and Liu, C. (2007), A novel aluminum-doped carbon nanotubes sensor for carbon monoxide ,/ourna/ of Molecular Structure THEOCHEM, 806,93-7. 

Some of these have semiconducting properties. The electric-arc method of producing Ceo also loads to a smaller number of fullerenes such as Cjo, which have less symmetrical molecular structures. It is also possible to produce forms of carbon in which the atoms are linked in a cylindrical, rather than spherical, framework with a diameter of a few nanometres. They ate known as buckytubes (or nanotubes). 

Fig.1 Molecular structure of 1 (a). Proposed structure of the nanotube of self-assembled 1 (b). TEM micrograph of the nanotubes of self-assembled 1. The TEM micrographs were provided courtesy of Prof. Myongsoo Lee of Yonsei University (c)...

Fig.23 Molecular structures of 9a and 9b (a). SEM micrograph of a mixture of the nanotubes and nanocoUs of self-assembled 9b. Reproduced with permission from [45] (b). Proposed mechanism of the formation of the ribbon from 9a and the nanotube from 9b...

Xiao, J. R., Gama, B. A. Gillespie, Jr J. W. (2005). An Analytical Molecular Structural Mechanics Model for the Mechanical Properties of Carbon Nanotubes. Int. J. Solids Struct, 42, 3075-3092. 

Li Chunyu, Chou Tsu-Wei. (2004). Modeling of Elastic Buckling of Carbon Nanotubes by Molecular Structural Mechanics Approach. Mech Mater, 36, 1047-1055. 

The above discussion provides summary of QSPR/QSAR approaches applied to classical, chemical compounds. However, an analysis devoted to nanomaterials having gigantic and complex molecular architecture lead to necessity of definition of new approaches for the predictive modelling, because the representation of their molecular structure by means of molecular graph and/or SMILES sometimes becomes very problematic (e.g. multi-walled carbon nanotubes [34], graphene [35]). In the first approximation, the optimal descriptors for such species should be a collector of all available data which are able to impact the physicochemical and/or biochemical behavior of nanomaterials. This concept is displayed in Fig. 12.6. 

A reduction of the required energy could be reached by the incorporation of conductive fillers such as heat conductive ceramics, carbon black and carbon nanotubes [103-105] as these materials allowed a better heat distribution between the heat source and the shape-memory devices. At the same time the incorporation of particles influenced the mechanical properties increased stiffness and recoverable strain levels could be reached by the incorporation of microscale particles [106, 107], while the usage of nanoscale particles enhanced stiffness and recoverable strain levels even more [108, 109]. When nanoscale particles are used to improve the photothermal effect and to enhance the mechanical properties, the molecular structure of the particles has to be considered. An inconsistent behavior in mechanical properties was observed by the reinforcement of polyesterurethanes with carbon nanotubes or carbon black or silicon carbide of similar size [3, 110]. While carbon black reinforced materials showed limited Ri around 25-30%, in carbon-nanotube reinforced polymers shape-recovery stresses increased and R s of almost 100% could be determined [110]. A synergism between the anisotropic carbon nanotubes and the crystallizing polyurethane switching segments was proposed as a possible... 

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