Molecular Descriptors for Natural Diamondoid Hydrocarbons and Quantitative Structure-Property Relationships for Their Chromatographic Data

Balaban, Alexandrù T.; Klein, Douglas J.; Dahl, Jeremy E. P.; Carlson, Robert M. K.

doi:10.2174/187409520701011302

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…We have devoted some effort to find structures for a given n with minimum cut bonds. This is equivalent to finding adamantanes (generally diamondoids) 17 with a given number of carbon atoms but with the minimum number of hydrogen atoms. Assuming that the classical adamantane (tetrahedral C 10 H 16 ) belongs to the class of such molecules, we proceeded generating other tetrahedral diamondoid clusters with apparently minimum number of H-atoms.…”

Section: Methodsmentioning

confidence: 99%

Characterization of large vacancy clusters in diamond from a generational algorithm using tight binding density functional theory

Slepetz

László

Gogotsi

et al. 2010

Phys. Chem. Chem. Phys.

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Point defects and pores in diamond affect its optical and electrical properties. We generated and evaluated a large number of vacancy V(n) clusters representing nanosized voids in diamonds for n up to 65. Our generational algorithm spawns the new generation n + 1 from the list of the most stable structures in the previous generation n. With energy as the only criterion, we generate a large structural diversity that allows their unbiased analysis. Since π-electron delocalization is important for carbon, we used quantum mechanical tight-binding density functional theory (TBDFT). Adamantane-like globular shapes are preferred for n up to ∼22. Beginning around n≈ 35, the most stable structures show overall oblate shapes with some irregularities. These novel structures have not been seen before because hitherto only highly regular structures were considered. We see local graphitization in these relaxed structures providing an atomistic justification for the widely used "slit pore" model. The preference for structures with minimum number of cut bonds diminishes as n increases. There are no particularly stable "magic" sizes for vacancy clusters larger than n = 22 indicating that these larger voids can easily incorporate small vacancies and vacancy clusters. Radial distribution analysis shows that unusual contact or bond distances in the 1.6 to 2.8 Å range appear in the vicinity of the internal surfaces of the vacancy clusters. Extremely long C-C bonds emerge as a result of structural relaxation of the dangling bonds in the vicinity of the vacancy clusters that cannot be simply described by ordinary sp(2)/sp(3) hybridization.

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Section: Methodsmentioning

confidence: 99%

Characterization of large vacancy clusters in diamond from a generational algorithm using tight binding density functional theory

Slepetz

László

Gogotsi

et al. 2010

Phys. Chem. Chem. Phys.

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“…Even the two enantiomeric tetramantanes could be separated by HPLC using methylated γ-cyclodextrin columns in reverse-phase mode . A collaboration between Balaban and Klein with Carlson and Dahl allowed the finding of quantitative structure–property relationships among gas chromatographic retention times, HPLC elution volumes, and structures of various diamondoid isomers . Resistance to pyrolysis and oxidation of diamondoids and methylated homologues facilitates their isolation.…”

Section: Introductionmentioning

confidence: 99%

Partitioned-Formula Periodic Tables for Diamond Hydrocarbons (Diamondoids)

Balaban

2012

J. Chem. Inf. Model.

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Isomeric diamond hydrocarbons (diamondoids or polymantanes) with the same number n of adamantane units share the same molecular formula C(Q)(CH)(T)(CH(2))(S) and can be divided into valence isomers (denoted as Q-T-S) by partitioning the number C = Q + T + S of their carbon atoms according to whether they are quaternary, tertiary, or secondary. Vertices of dualists are the centers of adamantane units, and dualist edges connect vertices of adjacent adamantane units (sharing a chair-shaped hexagon). Dualists of diamondoids are hydrogen-depleted skeletons of staggered alkane or cycloalkane rotamers. Diamondoids with acyclic dualists can be classified as catamantanes, those having dualists with chair-shaped six-membered rings as perimantanes, and those having dualists with higher-membered rings that are not perimeters of hexagon-aggregates as coronamantanes. Diamondoids with n adamantane units may be classified into regular catamantanes when the molecular formula is C(4n+6)H(4n+12), and irregular polymantanes (catamantanes or perimantanes) when the number of carbon atoms is lower than 4n + 6. The derivation is presented of formula-periodic tables of regular and irregular diamondoids that allow a better understanding of the shapes and properties of these hydrocarbons for which many applications are predicted.

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Ode to the Chemical Element Carbon

Balaban

2015

Exotic Properties of Carbon Nanomatter

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Molecular Descriptors for Natural Diamondoid Hydrocarbons and Quantitative Structure-Property Relationships for Their Chromatographic Data

Cited by 3 publications

References 19 publications

Characterization of large vacancy clusters in diamond from a generational algorithm using tight binding density functional theory

Characterization of large vacancy clusters in diamond from a generational algorithm using tight binding density functional theory

Partitioned-Formula Periodic Tables for Diamond Hydrocarbons (Diamondoids)

Ode to the Chemical Element Carbon

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