Paul Adriaan Van Der Schaaf

Synthesis and reactivity of novel ruthenium carbene catalysts. X-ray structures of [RuCl2(CHSC6H5)(PiPr3)2] and [RuCl2(CHCH2CH2-C,N-2-C5H4N)(PiPr3)]

Abstract Two novel classes of very air-stable ruthenium carbene complexes have been developed. The arylthio substituted ruthenium carbenes containing two bulky phosphines are deep purple solids, whereas the 2-pyridylethanyl substituted ruthenium carbene complexes contain only one bulky phosphine and are light-brown colored. One member of each class has been characterized with X-ray crystallography. The metathesis activity of these complexes has been investigated in the polymerization of dicyclopentadiene. Several excellent catalysts were identified. Desired geltimes and initiation temperatures could be easily tuned by changing the substitution pattern on the pendant ligand in the 2-pyridylethanyl substituted ruthenium carbenes.

High-performance flexible bottom-gate organic field-effect transistors with gravure printed thin organic dielectric

One of the key advantages of organic field-effect transistors (OFETs) is their ability to form flexible, conformable and lightweight electronic devices, e.g. radio frequency identification (RFID) tags,[1] microprocessors[2] and flexible displays.[3] These require fabrication over large-areas on flexible plastic substrates, the poor dimensional stability of such substrates creating the additional demand of low-temperature processing (<200 °C).[4] While high performance source, drain and gate electrodes and interconnects require metal evaporation under vacuum, ideally the dielectric and organic semiconductor (OSC) should be processed from solution under ambient conditions to reduce fabrication costs. Regarding device architecture, OFETs with a bottom-gate (BG) bottom-contact (BC) geometry (Figure u200b1c)1c) have an advantage in that the organic semiconducting layer is deposited last.[5] This affords easy fabrication and patterning of micron-scale OFET channels, electrodes and interconnects by conventional photolithographic methods, whilst avoiding exposure of the active OSC material to UV radiation and aggressive or solubilising chemicals. Furthermore, this architecture is compatible with vacuum sublimation or vapour phase techniques for OSC deposition, allowing access to a wide range of high-performance materials. Such OFETs can form the building blocks of high performance, low-cost electronic circuitry.

Thermal- and photoinduced ring-opening metathesis polymerization (ROMP)/(PROMP): an efficient tool in polymer chemistry

Abstract Properties and applications of newly developed homogeneous ring-opening metathesis polymerization catalysts as well as photoinduced ring-opening metathesis polymerization catalysts are discussed. It is shown that simple alkyl complexes, e.g. [W(ue605NPh)(CH 2 SiMe 3 ) 3 Cl] as well as [Ru(arene) 2 ] 2+ or [Ru(NC–R) 6 ] 2+ complexes act as one-component Photo-ROMP initiators. Catalysts with good thermal latency are described for both classes. High quantum yields are observed for the photochemically induced solvation of Ru(II) complexes. Polymer structure and kinetic aspects of the reaction are consistent with [Ru(solvent) 6 ] 2+ acting as the catalytically active species. The mechanism of aqueous ROMP with Ru(II) salts is discussed, which differs considerably from the classical ROMP reaction with Schrock-type catalysts in the sense that it is a chain reaction and not a living polymerization. Homo- and copolymers using exo-oxa-norbornene-carboximide ester derivatives were prepared with the ROMP technology and used, inter alia, to formulate very sensitive positive tone high-resolution microresists.

59.1: Invited Paper: Optoelectronic OLED Modeling for Device Optimization and Analysis

Organic light-emitting devices (OLEDs) consist of a stack of multiple thin film layers whose thicknesses influence both the optical and electronic performance. Upon injection and transport, the charge carriers may recombine to form excitons that diffuse and decay radiatively, thus leading to distinct recombination and emission zone profiles that determine device performance. Suitable simulation tools that allow a better understanding and efficient optimization of organic optoelectronics devices and materials are desirable.

A 14-electron ruthenium hydride: the key intermediate in the synthesis of ruthenium carbene complexes; X-ray structure of [RuHCl(PPri3)2]

A simple one-pot procedure for the synthesis of ruthenium nbenzylidenes (Grubbs’ catalyst) has been developed in which a novel, nhighly reactive 14-electron ruthenium monohydride, prepared from n[RuCl2(cod)] and two bulky phosphines in boiling propan-2-ol nwithout the use of hydrogen gas, is reacted with hydrogen chloride, an nalkyne and styrene.