Predictions of relative stabilities among series of carborane isomers by the criterion of topological charge stabilization

Ott, Jane J.; Gimarc, Benjamin M.

doi:10.1021/ja00275a011

Cited by 87 publications

(54 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, the carbon‐germanium triangulenes 1g – 4g substantially differ from carbon triangulenes 1a – 4a , they have non‐planar structure preventing effective delocalization of the unpaired electrons (see Table for exchange coupling constants) and are characterized by significant loss of aromaticity. These results are in accord with the rule of topological charge stabilization and the conclusion on that in mixed‐composition triangulenes more electronegative atoms prefer to take a‐positions.…”

Section: Resultssupporting

confidence: 90%

Germanium, carbon‐germanium, and silicon‐germanium triangulenes

2015

View full text Add to dashboard Cite

A series of germanium-containing triangular molecules have been studied by density functional theory (DFT) calculations. The triangulene topology of the compounds provides for their high-spin ground states and strong sign alternation of spin density and atomic charge distributions. High values of the exchange coupling constants witness ferromagnetic ordering of electronic structures of all studied triangulenes. The compounds bearing more electronegative atoms in a-positions of the triangular networks possess higher aromatic character and stronger ferromagnetic ordering.

show abstract

Section: Resultssupporting

confidence: 90%

Germanium, carbon‐germanium, and silicon‐germanium triangulenes

2015

View full text Add to dashboard Cite

show abstract

“…1 The method of topological charge stabilization assigns preferred locations for electronegative heteroatoms based on simple atomic charge distributions calculated for a common isostructural, isoelectronic, but homoatomic analog.2'3 Other authors have also predicted the order of stabilities of carborane isomers using empirical valence t h e~r y~-~ or a fragment molecular orbital a p p r o a~h .~ Although our predictions agree with all available experimental evidence we were able to assess the relative stabilities of many higherenergy isomers which are unknown experimentally. Therefore, to test our qualitative predictions, we have performed ab initio SCF MO calculations for each case.…”

Section: Introductionmentioning

confidence: 99%

Optimized Structures and Relative Stabilities of the Carboranes from Ab Initio Calculations

Ott

Gimarc

1986

J Comput Chem

Self Cite

View full text Add to dashboard Cite

A b initio calculations at the STO-3G level were performed on almost all of the possible isomers for the entire series of closo-carboranes, C2Bn-2Hn, 5 5 n 5 12. Geometry optimizations using the gradient method were also included in all calculations. We report here the relative energies obtained for the various isomers as well as the optimized structures. These calculations confirm our previous predictions of relative stabilities obtained from topological charge stabilization. Comparisons of our structures with those from experimental data provide us with a measure of reliability for bond distances obtained using a b initio SCF MO calculations at the STO-3G level. Results from the geometry optimization substantiated the experimentally known fluxional behavior of the 8 and 11 atom polyhedra.

show abstract

“…32,36,[40][41][42] At least Si 4 C 2 H 2 , and perhaps other members of this series of clusters is very probable to exist in interstellar space. 32,36,[40][41][42] At least Si 4 C 2 H 2 , and perhaps other members of this series of clusters is very probable to exist in interstellar space.…”

Section: Discussionmentioning

confidence: 99%

“…32,36,[40][41][42] At least Si 4 C 2 H 2 , and perhaps other members of this series of clusters is very probable to exist in interstellar space. [40][41][42] It would be perhaps interesting to further investigate the extent of this "dramatic" similarity, at least in three possible directions: ͑1͒ in the direction of increasing n, ͑2͒ in the direction of the possible electrophylic substitutions ͑in analogy to carboranes͒, and ͑3͒ toward other possible similar species, such as C 4 Si n H 4 in analogy to C 4 B n H n+4 . By removing the H atoms and reoptimizing the geometry, the lowest energy structures of the corresponding nonhydrogenated clusters can be obtained ͑not from the global energy minimum structure͒.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

A new class of silicon-carbon clusters: A full study of the hydrogenated SinC2H2, n=3,4,5, clusters in comparison with their isoelectronic carboranes C2BnHn+2

Zdetsis

2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

The structural and electronic characteristics of the Si(n)C(2)H(2), n=3,4,5, clusters are studied by ab initio calculations based on coupled cluster and density functional theory using the hybrid B3LYP functional. It is demonstrated that all three clusters are structurally and electronically homologous to the corresponding isoelectronic organometallic carboranes C(2)B(n)H(n+2). This homology, which is in full agreement with the analogy of Si(6) (2-) and B(6)H(6) (2-) demonstrated recently by the author [J. Chem. Phys. 127, 014314 (2007)], includes not only the ground states but also the lower-lying isomers as well. These lowest lying isomers can be obtained by ortho, para, and meta substitutions from the corresponding Si(n) (2-), n=3,4,5, dianions. The energetic ordering of the low-lying isomers is in full agreement with the known valence and topological charge stability rules developed for carboranes. The hydrogenated clusters are much more stable than their nonhydrogenated counterparts. It is suggested that Si(3)C(2)H(2), Si(4)C(2)H(2), and Si(5)C(2)H(2), which can be probably found in interstellar space, are special examples of a general class of silicon-carbon clusters of the form Si(n)C(2)H(2), with analogous properties and similarities to the corresponding carboranes C(2)B(n)H(n+2). It is furthermore illustrated that the lowest energy structures of the Si(n)C(2) clusters can be obtained through a systematic and straightforward procedure from the Si(n)C(2)H(2) clusters. The present results could hopefully make possible the exploitation of the rich borane and carborane chemistry for the design and development of novel silicon and silicon-carbon composite nanomaterials.

show abstract

Predictions of relative stabilities among series of carborane isomers by the criterion of topological charge stabilization

Cited by 87 publications

References 6 publications

Germanium, carbon‐germanium, and silicon‐germanium triangulenes

Germanium, carbon‐germanium, and silicon‐germanium triangulenes

Optimized Structures and Relative Stabilities of the Carboranes from Ab Initio Calculations

A new class of silicon-carbon clusters: A full study of the hydrogenated SinC2H2, n=3,4,5, clusters in comparison with their isoelectronic carboranes C2BnHn+2

Contact Info

Product

Resources

About