Douglas Philp

Bio: Douglas Philp is an academic researcher from University of St Andrews. The author has contributed to research in topics: Cyclophane & Cycloaddition. The author has an hindex of 41, co-authored 159 publications receiving 8145 citations. Previous affiliations of Douglas Philp include ETH Zurich & University of Sheffield.

Self-Assembly in Natural and Unnatural Systems

Abstract: Although there are no fundamental factors hindering the development of nanoscale structures, there is a growing realization that “engineering down” approaches, in other words a reduction in the size of structures generated by lithographic techniques below the present lower limit of roughly 1 μm, may become impractical. It has, therefore, become increasingly clear that only by the development of a fundamental understanding of the self-assembly of large-scale biological structures, which exist and function at and beyond the nanoscale, downwards, and the extension of our knowledge regarding the chemical syntheses of small-scale structures upwards, can the gap between the promise and the reality of nanosystems be closed. This kind of construction of nanoscale structures and nanosystems represents the so-called “bottom up” or “engineering up” approach to device fabrication. Significant progress can be made in the development of nanoscience by transferring concepts found in the biological world into the chemical arena. Central to this mission is the development of simple chemical systems capable of instructing their own organization into large aggregates of molecules through their mutual recognition properties. The precise programming of these recognition events, and hence the correct assembly of the growing superstructure, relies on a fundamental understanding and the practical exploitation of non-covalent bonding interactions between and within molecules. The science of supramolecular chemistry—chemistry beyond the molecule in its very broadest sense—has started to bridge the yawning gap between molecular and macro-molecular structures. By utilizing inter-actions as diverse as aromatic π–π stacking and metal–ligand coordination for the information source for assembly processes, chemists have, in the last decade, begun to use biological concepts such as self-assembly to construct nanoscale structures and superstructures with a variety of forms and functions. Here, we provide a flavor of how self-assembly operates in natural systems and can be harnessed in unnatural ones.

Selbstorganisation in natürlichen und in nichtnatürlichen Systemen

Abstract: Zwar steht der Entwicklung von nanometergrosen Strukturen prinzipiell nichts im Wege, doch setzt sich immer mehr die Auffassung durch, das sich Strukturminiaturisierungen unter die gegenwartig durch lithographische Techniken erreichbare 1-μ-Grenze als nicht mehr praktikabel erweisen werden. Es wurde daher deutlich, das nur durch ein grundlegendes Verstandnis der Selbstorganisation von funktionellen makroskopischen biologischen Strukturen mit Abmessungen im Nanometerbereich und sogar darunter (Verkleinerungsansatz) und durch die Erweiterung unseres Wissens uber die chemische Synthese von mikroskopischen Strukturen (Vergroserungsansatz) die Brucke zwischen Anspruch und Wirklichkeit bei Nanosystemen geschlagen werden kann. Die Konstruktion von Nanostrukturen und -systemen aus kleinen Molekulbausteinen ist das „engineering-up” zum Aufbau von molekularen Funktionseinheiten. Bedeutende Fortschritte konnen auf dem Gebiet der Nanowissenschaften erzielt werden, wenn die Konzepte, die in der Biologie gefunden wurden, auf die Chemie ubertragen werden. Im Zentrum dieser Aufgabe steht die Entwicklung von einfachen chemischen Systemen, die sich selbst durch gegenseitige Erkennung zu groseren Molekulaggregaten organisieren konnen. Die genaue Programmierung derartiger Erkennungsprozesse und somit auch der korrekte Aufbau der Uberstrukturen setzen ein fundamentales Verstandnis und die Nutzung inter- sowie intramolekularer nichtkovalenter bindender Wechselwirkungen voraus. Die supramolekulare Chemie – eine Chemie, die in jeder Hinsicht uber die Chemie der Molekule hinausgeht – hat begonnen, den grosen Graben zwischen molekularen und makromolekularen Strukturen zu schliesen. Durch Nutzung von so unterschiedlichen Wechselwirkungen wie aromatischen π-Stapel- und Metall-Ligand-Koordinationswechselwirkungen als Informationsquellen der Aufbauprozesse haben Chemiker in den letzten zehn Jahren biologische Konzepte wie die Selbstorganisation zur Konstruktion von Nanostrukturen und Uberstrukturen mit einer Vielzahl von Formen und Funktionen herangezogen. Wir wollen hier einen Eindruck davon vermitteln, wie die Selbstorganisation in naturlichen Systemen funktioniert und wie diese Prinzipien nutzbringend auf nichtnaturliche Systeme angewendet werden konnen.

Electronics using hybrid-molecular and mono-molecular devices

Abstract: The semiconductor industry has seen a remarkable miniaturization trend, driven by many scientific and technological innovations. But if this trend is to continue, and provide ever faster and cheaper computers, the size of microelectronic circuit components will soon need to reach the scale of atoms or molecules—a goal that will require conceptually new device structures. The idea that a few molecules, or even a single molecule, could be embedded between electrodes and perform the basic functions of digital electronics—rectification, amplification and storage—was first put forward in the mid-1970s. The concept is now realized for individual components, but the economic fabrication of complete circuits at the molecular level remains challenging because of the difficulty of connecting molecules to one another. A possible solution to this problem is ‘mono-molecular’ electronics, in which a single molecule will integrate the elementary functions and interconnections required for computation.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

Abstract: Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.