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Designing novel Sn-Bi, Si-C and Ge-C nanostructures, using simple theoretical chemical similarities.

Zdetsis AD - Nanoscale Res Lett (2011)

Bottom Line: When successful, these concepts are very powerful and transparent, leading to a large variety of nanomaterials based on Si and other group 14 elements, similar to well known and well studied analogous materials based on boron and carbon.Some of the so called predicted structures have been already synthesized, not necessarily with the same rational and motivation.Finally, it is anticipated that such powerful and transparent rules and analogies, in addition to their predictive power, could also lead to far-reaching interpretations and a deeper understanding of already known results and information.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics University of Patras, GR 26500, Patra, Greece. zdetsis@upatras.gr.

ABSTRACT
A framework of simple, transparent and powerful concepts is presented which is based on isoelectronic (or isovalent) principles, analogies, regularities and similarities. These analogies could be considered as conceptual extensions of the periodical table of the elements, assuming that two atoms or molecules having the same number of valence electrons would be expected to have similar or homologous properties. In addition, such similar moieties should be able, in principle, to replace each other in more complex structures and nanocomposites. This is only partly true and only occurs under certain conditions which are investigated and reviewed here. When successful, these concepts are very powerful and transparent, leading to a large variety of nanomaterials based on Si and other group 14 elements, similar to well known and well studied analogous materials based on boron and carbon. Such nanomaterias designed in silico include, among many others, Si-C, Sn-Bi, Si-C and Ge-C clusters, rings, nanowheels, nanorodes, nanocages and multidecker sandwiches, as well as silicon planar rings and fullerenes similar to the analogous sp2 bonding carbon structures. It is shown that this pedagogically simple and transparent framework can lead to an endless variety of novel and functional nanomaterials with important potential applications in nanotechnology, nanomedicine and nanobiology. Some of the so called predicted structures have been already synthesized, not necessarily with the same rational and motivation. Finally, it is anticipated that such powerful and transparent rules and analogies, in addition to their predictive power, could also lead to far-reaching interpretations and a deeper understanding of already known results and information.

No MeSH data available.


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The region of the periodical table examined here. Different colours of diagonal lines and element symbols signify different type or level of (co)relation.
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Figure 2: The region of the periodical table examined here. Different colours of diagonal lines and element symbols signify different type or level of (co)relation.

Mentions: In addition to such global regularities, there could be other local analogies which are also based on the number of valence electrons. In general, it would be expected that two atoms or molecules having the same number of valence electrons (isovalent) should have similar properties and should, in principle, be able to replace each other in larger complex structures and nanocomposites. Such a local diagonal relationship between boron and silicon can be invoked by recognizing that, basically, one B-H unit has the same number (four) of valence electrons (is isovalent) with Si. We could then assume that, under certain conditions to be specified later, we could replace a B-H unit in a boron hydride molecule by Si and still have a stable molecule. We could also expect that the reverse could be also true but we will not consider it here. Let us write the above relation as BH→Si (1). It is clear that isovalency, although necessary, is not sufficient for such equivalence or replacement relationships. For instance, we cannot write Si→C in general. In addition, the relationship BH→C does not work either. Experience shows that we could, instead, have BH1-→CH (2). This is a horizontal relation involving five valence electrons. The relation (CH)→(SiH) (3) also seems to works as C20H20 or C60H60 fulleranes are very similar to Si20H20 or Si60H60 fullerens [6-9]. Relation (3) could be also written as (CH4)→(SiH4) (3') to indicate the equivalence covalent (sp3 bonded structures). Moreover, since Si, Ge, Sn and Pb are in the same column of the periodical table, we could, in principle, write: Si→Ge→Sn→Pb (4), bearing in mind the inert pair effect, although it is clear that Si and Pb are not similar. However, it is not unreasonable to expect that (BH)→Ge, (BH)→Sn, (BH)→Pb (5) would work as a total substitution (which is roughly correct). Relation (5) involves four valence electrons. As in relation (2), which involves five valence electrons, we can write more five-valence electron relations as: BH1-→CH→P, BH1-→CH→As (6) or BH1-→CH→Sb, BH1-→CH→Bi (7), involving the group 15 elements. Relations (1) and (2) [10-16] and analogy (3) [6-9] have been successfully tested. The author has also tested CH→Si1- (14) which has lead to a simple rule of thumb for constructing planar aromatic Si structures similar to benzene and others [17-19]. This rule, suggested by Zdetsis, has been also tested and verified by Jin et al. [20]. Finally, analogies (4) through (7) have been demonstrated to be valid by the author [21-24]. Thus, in this study, the working area of the periodic table will be as in Figure 2. Even within this limited region of the periodical table, it is difficult to identify similar or homologous molecular systems.


Designing novel Sn-Bi, Si-C and Ge-C nanostructures, using simple theoretical chemical similarities.

Zdetsis AD - Nanoscale Res Lett (2011)

The region of the periodical table examined here. Different colours of diagonal lines and element symbols signify different type or level of (co)relation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211452&req=5

Figure 2: The region of the periodical table examined here. Different colours of diagonal lines and element symbols signify different type or level of (co)relation.
Mentions: In addition to such global regularities, there could be other local analogies which are also based on the number of valence electrons. In general, it would be expected that two atoms or molecules having the same number of valence electrons (isovalent) should have similar properties and should, in principle, be able to replace each other in larger complex structures and nanocomposites. Such a local diagonal relationship between boron and silicon can be invoked by recognizing that, basically, one B-H unit has the same number (four) of valence electrons (is isovalent) with Si. We could then assume that, under certain conditions to be specified later, we could replace a B-H unit in a boron hydride molecule by Si and still have a stable molecule. We could also expect that the reverse could be also true but we will not consider it here. Let us write the above relation as BH→Si (1). It is clear that isovalency, although necessary, is not sufficient for such equivalence or replacement relationships. For instance, we cannot write Si→C in general. In addition, the relationship BH→C does not work either. Experience shows that we could, instead, have BH1-→CH (2). This is a horizontal relation involving five valence electrons. The relation (CH)→(SiH) (3) also seems to works as C20H20 or C60H60 fulleranes are very similar to Si20H20 or Si60H60 fullerens [6-9]. Relation (3) could be also written as (CH4)→(SiH4) (3') to indicate the equivalence covalent (sp3 bonded structures). Moreover, since Si, Ge, Sn and Pb are in the same column of the periodical table, we could, in principle, write: Si→Ge→Sn→Pb (4), bearing in mind the inert pair effect, although it is clear that Si and Pb are not similar. However, it is not unreasonable to expect that (BH)→Ge, (BH)→Sn, (BH)→Pb (5) would work as a total substitution (which is roughly correct). Relation (5) involves four valence electrons. As in relation (2), which involves five valence electrons, we can write more five-valence electron relations as: BH1-→CH→P, BH1-→CH→As (6) or BH1-→CH→Sb, BH1-→CH→Bi (7), involving the group 15 elements. Relations (1) and (2) [10-16] and analogy (3) [6-9] have been successfully tested. The author has also tested CH→Si1- (14) which has lead to a simple rule of thumb for constructing planar aromatic Si structures similar to benzene and others [17-19]. This rule, suggested by Zdetsis, has been also tested and verified by Jin et al. [20]. Finally, analogies (4) through (7) have been demonstrated to be valid by the author [21-24]. Thus, in this study, the working area of the periodic table will be as in Figure 2. Even within this limited region of the periodical table, it is difficult to identify similar or homologous molecular systems.

Bottom Line: When successful, these concepts are very powerful and transparent, leading to a large variety of nanomaterials based on Si and other group 14 elements, similar to well known and well studied analogous materials based on boron and carbon.Some of the so called predicted structures have been already synthesized, not necessarily with the same rational and motivation.Finally, it is anticipated that such powerful and transparent rules and analogies, in addition to their predictive power, could also lead to far-reaching interpretations and a deeper understanding of already known results and information.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics University of Patras, GR 26500, Patra, Greece. zdetsis@upatras.gr.

ABSTRACT
A framework of simple, transparent and powerful concepts is presented which is based on isoelectronic (or isovalent) principles, analogies, regularities and similarities. These analogies could be considered as conceptual extensions of the periodical table of the elements, assuming that two atoms or molecules having the same number of valence electrons would be expected to have similar or homologous properties. In addition, such similar moieties should be able, in principle, to replace each other in more complex structures and nanocomposites. This is only partly true and only occurs under certain conditions which are investigated and reviewed here. When successful, these concepts are very powerful and transparent, leading to a large variety of nanomaterials based on Si and other group 14 elements, similar to well known and well studied analogous materials based on boron and carbon. Such nanomaterias designed in silico include, among many others, Si-C, Sn-Bi, Si-C and Ge-C clusters, rings, nanowheels, nanorodes, nanocages and multidecker sandwiches, as well as silicon planar rings and fullerenes similar to the analogous sp2 bonding carbon structures. It is shown that this pedagogically simple and transparent framework can lead to an endless variety of novel and functional nanomaterials with important potential applications in nanotechnology, nanomedicine and nanobiology. Some of the so called predicted structures have been already synthesized, not necessarily with the same rational and motivation. Finally, it is anticipated that such powerful and transparent rules and analogies, in addition to their predictive power, could also lead to far-reaching interpretations and a deeper understanding of already known results and information.

No MeSH data available.


Related in: MedlinePlus