Diamondoids are cage-like, ultra stable, saturated ringed hydrocarbons, which have a diamond-like structure consisting of a number of six-member carbon rings fused together. Adamantane is the cage compound prototype and the simplest diamondoid molecule. Diamondoids Molecules aims to present these fascinating substances in a novel fashion. The more intriguing facets of diamondoid molecules are comprehensively exposed and discussed, bringing state-of-the-art information to the reader, along with the history, fundamentals and perspectives of diamondoid science and technology.This groundbreaking book, especially devoted to diamondoid molecules, is of critical importance to the global techno-scientific community, and will be of great interest in many research fields such as chemistry, physics, material science, geology, and biological sciences. Moreover, it will attract readers from industrial, government and environmental agencies as well as scholars.

Diamondoids are cage-like, ultra stable, saturated ringed hydrocarbons, which have a diamond-like structure consisting of a number of six-member carbon rings fused together. Adamantane is the cage compound prototype and the simplest diamondoid molecule. Diamondoids Molecules aims to present these fascinating substances in a novel fashion. The more intriguing facets of diamondoid molecules are comprehensively exposed and discussed, bringing state-of-the-art information to the reader, along with the history, fundamentals and perspectives of diamondoid science and technology. This groundbreaking book, especially devoted to diamondoid molecules, is of critical importance to the global techno-scientific community, and will be of great interest in many research fields such as chemistry, physics, material science, geology, and biological sciences. Moreover, it will attract readers from industrial, government and environmental agencies as well as scholars.

The Chemistry of Diamondoids Comprehensive resource on an important and fascinating compound class, covering synthesis, properties, functionalization, and applications in organic synthesis, materials science, and more The Chemistry of Diamondoids gives a state-of-the-art overview of all aspects of diamondoid chemistry, covering nomenclature, natural occurrence, chemical and physical properties, along with synthesis and functionalization of diamondoids as well as their applications as molecular building blocks in organic synthesis, polymer and materials science, nanotechnology, and medicinal chemistry. The book concludes with a perspective towards future developments in the field, thereby drawing attention to areas open for discovery. Written by experts in the field, The Chemistry of Diamondoids includes information on: Naturally occurring diamondoids, their formation, and the role they play in the petroleum industry and in geosciences, plus man-made approaches to prepare them on large scale Growing diamond from diamondoids via seeding, preparation and properties of diamondoid oligomers and doped diamondoids C–H-bond functionalization, a precondition for their use in many applications, and fine-tuning of diamondoid properties by precise cage substitution reactions With its all-encompassing approach, The Chemistry of Diamondoids is a valuable guide for newcomers and researchers in organic chemistry and materials science interested in modern synthetic methods and organic functional materials.

Over the past few decades, carbon nanomaterials, most commonly fullerenes, carbon nanotubes, and graphene, have gained increasing interest in both science and industry, due to their advantageous properties that make them attractive for many applications in nanotechnology. Another class of the carbon nanomaterials family that has slowly been gaining (re)newed interest is diamond molecules, also called diamondoids, which consist of polycyclic carbon cages that can be superimposed on a cubic diamond lattice. Derivatives of diamondoids are used in pharmaceutics, but due to their promising properties—well-defined structures, high thermal and chemical stability, negative electron affinity, and the possibility to tune their bandgap—diamondoids could also serve as molecular building blocks in future nanodevices. This book is the first of its kind to give an exhaustive overview of the structures, properties, and current and possible future applications of diamondoids. It contains a brief historical account of diamondoids, from the discovery of the first diamondoid member, adamantane, to the isolation of higher diamondoids about a decade ago. It summarizes the different approaches to synthesizing diamondoids. In particular, current research on the conventional organic synthesis and new approaches based on microplasmas generated in high-pressure and supercritical fluids are reviewed and the advantages and disadvantages of the different methods discussed. The book will serve as a reference for advanced undergraduate- and graduate-level students in chemistry, physics, materials science, and nanotechnology and researchers in macromolecular science, nanotechnology, chemistry, biology, and medicine, especially those with an interest in nanoparticles.

Recent discoveries in novel forms of nanocarbon, from graphene to carbon fiber, have invigorated research into carbon based nanostructures. Until recently, however, this research was almost entirely focused on graphite-like structures while relatively little work was being done on the smaller members of the nano-diamond series, known as the diamondoids. The discovery of large quantities of these diamondoids in petroleum reserves has renewed interest in these unusual molecular nano-particles. We present here a survey of the physical properties of these diamondoids and novel materials which are created from them. We find that they have a number of properties which make them ideal for the study of nanoparticle physics as well as properties which give them exciting potential for a wide range of applications. The diamondoids are small molecules of hydrogen and carbon which have the same rigid cage structure as bulk diamond. The smallest diamondoid, adamantane, has ten carbons that comprise a single diamond cage. Larger and larger diamondoids can be constructed by continuing to add diamond cages onto the molecule, and diamondoids with as many as 11 cages have been detected. These different diamond species can be separated and single morphologies can be isolated to give pure samples of a single shape and size. This allows the production of molecular crystals of diamondoids, which possess new properties owing to the interactions between the nanoparticles in the regular lattice structure. Much work has been done to predict and characterize the basic physical properties of the diamondoids, and we give a summary of these past experiments. These include a number of different spectroscopy and microscopy techniques used on the diamondoids in both the solid state and the gas phase, as well as materials made from chemically functionalized diamondoids. The most studied of these chemically altered diamondoids are the diamondoid-thiols, which are useful for producing single monolayers of diamondoids on metal surfaces. These diamondoid-thiol monolayers have shown great potential for use in various electron emission devices. In this work we focus primarily on solid state diamondoid properties as well as the properties of these diamondoid-thiol self-assembled monolayers. One property discussed is the photoluminescence of the diamondoids in the solid state. This is studied by producing ultra-pure diamondoid crystals and exciting photoluminescence with a UV light source. We find that the diamondoids studied all display similar emission and excitation spectra, which are similar in many ways to the spectra seen from diamondoids in the gas phase as well as other saturated hydrocarbons. However, the diamondoids in the solid state exhibit several unique properties as well. The excitation and emission wavelengths are both red shifted by more then 1 eV compared to the same molecules in the gas phase and are lower than any other saturated hydrocarbon which has been measured. Additionally, the diamondoids exhibit the highest photoluminescence quantum yield ever measured in a saturated hydrocarbon. These unusual properties stem from the strong electronic interactions between the molecule in the solid state. Another solid state property discussed is the dielectric constant, which is studied using microwave impedance measurement. We find that the diamondoids' dielectric constants are significantly lower than that of bulk diamond, as low as 2.46 compared with 5.66 for bulk diamond. This property puts the diamondoids on par with state-of-the-art low-k dielectric materials for use in electronics. Low-k dielectrics are critical for the performance of future microelectronics and the diamondoids are a promising potential material for this application. The ionization potential of the diamondoids in the solid state is also studied. Much like the photoluminescence energies, we find that the ionization energy is greatly reduced in the solid state compared with the gas phase. This is because there are strong quantum confinement effects for the final-state ion in the gas phase that are not present in the bulk crystal. This is another strong indication of electronic interactions between the molecules in the solid state. The ionization potential is also compared with bulk diamond and it is found that the diamondoids are trending slowly towards the bulk value as their size is increased but quantum confinement is still a factor for diamondoids as large as tetramantane (4 cages). An interesting result of these measurements is that the diamondoids appear to have negative electron affinity in the solid state, a property which makes them ideal as electron emitters. The band structure of the diamondoids in the solid state is studied as well, both in theory and experiment. Previous theoretical studies indicate that the lower diamondoids should have a direct band-gap, which is desirable for most optics applications. We extend this study to include several tetramantanes, and find that the more symmetric molecule studied ([121]tetramantane) should have a direct gap while the less symmetric one ([123]tetramantane) should have an indirect gap. We attempt to measure the nature of the gap using resonant inelastic x-ray scattering but the results are inconclusive. We find that the data for the [121]tetramantane are consistent with a direct gap but the data for [123]tetramantane are inconclusive due to severe beam damage to the sample which prevents the collection of sufficient data. We additionally discuss several properties of the self assembled monolayers of diamondoid-thiols. Previous work has shown that these films produce an unusual effect in photoemission experiments where a majority of electrons are emitted in a single sharp peak at low energy with a full width-half max of less than 0.4 eV. We investigate the origin of this unique effect and find that it comes from a combination of negative electron affinity, a property shared with bulk diamond, and an unusually short electron mean free path, a property that appears to be new and unique to the diamondoids. We confirm this short electron mean free path experimentally and perform computer simulations to determine that the short interaction length is a sufficient explanation for the production of the monochromatic peak. We also investigate a technique for making these films more stable, which is a prerequisite for using them in any device application. Our technique is to coat the diamondoid monolayer with a thin film of CsBr, which is a stable, protective over-layer that is relatively transparent to electrons. As an added bonus, this CsBr film also reduces the work function of the emitter, increasing the quantum yield significantly. We find that the combined diamondoid-thiol/CsBr film has a lower energy spread than a typical CsBr emitter but has a longer lifetime than an unprotected diamondoid monolayer emitter. We also discuss initial efforts to characterize the properties of diamondoid monolayers in field emission devices. This is studied by attaching the diamondoid to gold-coated nanowire field emission tips. This experimental setup has the advantage that the same sample can be characterized with and without the diamondoid monolayer present, allowing us to determine precisely the effect of the diamondoid on the work function of the emitter. We find that there is a small reduction in the work function when a lower diamondoid is used, but a huge reduction, as much as 3 eV, when a higher diamondoid is used. This indicates that the diamondoids may be extremely useful for field emission devices is they can be made more stable. Finally, we discuss the origin of the diamondoids in petroleum through a first principles density function theory study of their thermodynamic properties. Through this technique we are able to predict the equilibrium concentration of diamondoids under the conditions where they are known to form. We find that purely random rearrangement reactions occurring at equilibrium in a high pressure, high temperature natural gas field are a sufficient mechanism for explaining the formation of diamondoids and their relative occurrence compared to other molecules and one another.

Volume is indexed by Thomson Reuters BCI (WoS). Carbon is an essential constituent element of all living organisms. A unique feature of carbon is the variety of forms that it can assume when two or more atoms bond. Carbon has thus attracted, and continues to attract, considerable R&D interest from researchers all over the world. The use of carbon in nanotechnology is a very promising area of research, and considerable government funding is being invested in carbon nanotechnology research.

Identification and characterization of new and novel materials is one of the major challenges facing the continued advancement of digital electronics. Traditionally, the electronics industry has been dominated by silicon. However, as devices begin to approach atomic scales, state-of-the-art electronics will have to increasingly embrace new and complementary materials, some of which bear little resemblance to their silicon brethren. Molecular systems and crystals that contain novel fermionic states have the potential to rapidly and greatly impact the electronics industry, given the right advances in fabrication and performance. This thesis reports the use of scanning tunneling microscopy to explore a variety of new materials that exhibit novel--and potentially marketable--electronic properties, yet that can also be synthesized using relatively low-cost and straightforward techniques. The first material is the family of diamondoid molecules, which represent an exciting new direction in the field of nanoscale carbon. These molecules are carbon cages consisting of the smallest caged subunits of the diamond lattice, with surface bonds saturated by hydrogen. While theoretically known to be stable, diamondoids have been experimentally inaccessible due to synthesis roadblocks and lack of natural sources, until recently purified from crude oil. This advancement allows for potential access to the unique and extreme properties of diamond (rigidity, thermal conductivity, wide band-gap, and doping behavior, among others) in nanoscale and molecular devices. Of particular interest is the cross-over regime between the molecule-like behavior expected of the smaller diamondoids and the properties of macroscopic diamond. The first part of this dissertation explores the hierarchical nature of these molecules, investigated at the single-molecule level with scanning tunneling microscopy (STM). I will present structural data showing the quality of self-assembled monolayers (SAMs) composed of a series of thiolated diamondoids, and the variation that emerges as the number of diamondoid cages increases. I-V spectroscopy (combined with density functional calculations) allows us to determine the energy band line-ups of the molecular orbitals. The robustness of the SAMs and the insulating behavior implied by spectroscopy suggest that--at the few-eV energy scale typical of STM--diamondoid thiol SAMs may be useful as rigid decoupling layers, tunable by appropriate choice of cage structure. Moving beyond thiolated molecules (which have well-documented uses in the field of molecular electronics), we have begun exploring more exotic diamondoid-based derivates as novel nanoelectronic elements. Over the past few decades, new fields of research have emerged based on the sp2 molecular forms of carbon such as graphene, fullerenes, and nanotubes. Materials that sit at the intersection of the sp2 and sp3 bonding structures are an exciting new area for nanoscale science, combining the unique electronic properties of these two very different hybridizations. I will introduce hybrid molecules that fuse the sp2 and sp3 allotropes-in the form of C60 fullerenes and diamondoids-into one well-defined molecular system. These molecules were synthesized with the intention of creating diode-like elements for single- or few-molecule electronic devices. STM measurements on SAMs of these molecules indeed show evidence of unconventional rectifying behavior. These measurements represent (to our knowledge) the first purely hydrocarbon rectifier, and demonstrate the emerging diversity of electronic phenomena observed in diamondoid-based molecules. The second half of this thesis turns from molecular systems to a particular set of crystalline systems that exhibit electrons that behave as Dirac fermions. These particles are very different from the standard electrons in metals or semiconductors in that they propagate relativistically, despite being confined to a solid state crystal. STM has proven to be an indispensable tool in characterizing the signatures of such particles. These materials have a host of technological applications, so lowering the cost of synthesis is an important research direction. I therefore survey a growth techniques by using STM to look for Dirac fermions in graphene and topological insulator systems. As in the molecular systems introduced above, STM studies are important in these Dirac systems because their unique transport behavior depends critically on their nanoscale properties.