Fifty years after the idea of C60 molecule

N/

Looking Back the Most Beautiful Molecule C60 after Quarter Century of Discovery Insert

On the occasion of silver anniversary of the C60 discovery, the present situation of C60 research is briefly analyzed from three distinct angles: molecule, solid and nanoparticle. With regard to molecular angle, the long pending problem of formation mechanism is almost solved by molecular dynamics approach hinted by Prigogine’s nonequilibrium thermodynamics. The C60 research is at the moment most active in chemistry, and some of the recent results are discussed here. Though C60 is closer to molecule than to the smallest nanoparticle in its outlook, a big future seems hidden in its application in nanotechnology.З нагоди срібної річниці з часу відкриття фулеренів коротко проаналізовано нинішню ситуацію з їх дослідженням. C60 розглянуто в трьох різних аспектах — молекула, тверде тіло та наночастинка. Стосовно молекулярного аспекту варто зазначити, що давню проблему механізму утворення фулеренів майже розв’язано за допомогою молекулярно-динамічного підходу, підказаного нерівноважною термодинамікою І. Пригожина. Нині найактивніше досліджують хімію C60. У статті розглянуто деякі з нещодавніх результатів у цій галузі. Хоча за своїми характеристиками C60 ближчий до молекул, ніж до найдрібніших наночастинок, його застосування в нанотехнологіях, схоже, таїть у собі великі перспективи.По случаю серебряной годовщины со времени открытия фуллеренов кратко проанализирована нынешняя ситуация с их исследованием. C60 рассматривается в трех различных аспектах — молекула, твердое тело и наночастица. Касательно молекулярного аспекта нельзя не отметить, что давно занимавшая умы ученых проблема механизма образования фуллеренов почти решена с помощью молекулярно-динамического подхода, подсказанного неравновесной термодинамикой И. Пригожина. Сегодня наиболее активно изучаются химические свойства C60. В статье обсуждаются некоторые последние результаты в этой области. Хотя по своим характеристикам C60 ближе к молекулам, чем к мельчайшим наночастицам, его применение в нанотехнологиях, похоже, таит в себе большие перспективы

Confirmation of the Electrostatic Self-Assembly of Nanodiamonds

A reliable explanation for the underlying mechanism responsible for the persistent aggregation and self-assembly of colloidal 5 nm diamond nanoparticles is critical to the development of nanodiamond-based technologies. Although a number of mechanisms have been proposed, validation has been hindered by the inherent difficulty associated with the identification and characterisation of the inter-particle interfaces. In this paper we present results of high resolution aberration corrected electron microscopy and complementary computer simulations to explicate the features involved, and confirm the electrostatic interaction mechanism as the most probable cause for the formation of agglutinates and agglomerates of primary particles.Comment: 9 pages (including Supplementary Information), accepted for publication by Nanoscal

Effects of Substituents on the Length of Central C(sp^3)-C(sp^3) Bond in Anthracene Photodimers and Related Molecules

Effects of substituents on the lengths of the central C–C single bond in the butterfly-shaped anthracene photodimers (1)–(7) and lepidopterenes (8) are studied. X-Ray analysis of the photodimer (10) of 9,10-difluoroanthracene gave a C(9)–C(10′) bond length of 1.631 (3)Å. An attempt to re-determine molecular structure of the photoisomer (5) of [2.2](9,10) anthracenophane (12) by neutron diffraction analysis is also reported [C(9)–C(10′): obs. 1.64(1), calc. 1.63(1)Å]. The D_2 structure that had been proposed for the minimum-energy conformation of (5) is questioned and the D_(2h) symmetric conformation is suggested on the basis of the diffraction results and MNDO calculations. The experimentally determined distances of the long central C–C bonds in these butterfly compounds including dianthronyl (9) are well reproduced by MNDO calculations with a standard deviation of 0.013 Å. Small but significant further elongation of the central C–C bond by up to 0.07 Å resulting from annulation of cyclobutane or cyclopentane ring in anthracene photodimers and from remote chlorine substitution in lepidopterene are interpreted in terms of the increased π→σ^* orbital interaction

Fabrication Process Independent And Robust Aggregation Of Detonation Nanodiamonds In Aqueous Media

In the past detonation nanodiamonds (DNDs), sized 3–5 nm, have been praised for their colloidal stability in aqueous media, thereby attracting vast interest in a wide range of applications including nanomedicine. More recent studies have challenged the consensus that DNDs are monodispersed after their fabrication process, with their aggregate formation dynamics poorly understood. Here we reveal that DNDs in aqueous solution, regardless of their post-synthesis de-agglomeration and purification methods, exhibit hierarchical aggregation structures consisting of chain-like and cluster aggregate morphologies. With a novel characterization approach combining machine learning with direct cryo-transmission electron microscopy and with X-ray scattering and vibrational spectroscopy, we show that their aggregate morphologies of chain and cluster ratios and the corresponding size and fractal dimension distributions vary with the post-synthesis treatment methods. In particular DNDs with positive ζ-potential form to a hierarchical structure that assembles aggregates into large networks. DNDs purified with the gas phase annealing and oxidation tend to have more chain-like aggregates. Our findings provide important contribution in understanding the DND interparticle interactions to control the size, polydispersity and aggregation of DNDs for their desired applications

A Simple and Soft Chemical Deaggregation Method Producing Single-Digit Detonation Nanodiamonds

Detonation nanodiamonds (DNDs) are a class of very small and spherical diamond nanocrystals. Used in polymer reinforcement materials, as drug delivery systems or as fluorescent biomarkers, only the final deaggregation step down to the single-digit nanometer size unfolds their full potential. All existing deaggregation methods rely on mechanical forces, such as high-power sonication or beads milling. We report a purely chemical deaggregation method by combining oxidation in air followed by a boiling acid treatment. Our DNDs are surface functionalized with carboxyl groups, the final boiling acid treatment removes primary metal contaminants and the nanoparticles remain dispersed over a wide pH range. Experiments can be easily carried out in a standard chemistry laboratory. This is a key step for many DND-based applications, ranging from material science to biological or medical applications and opens a way for inexpensive mass production on industrial scale.</p