Cinnoline chemistry XIII. 4-aziridinocinnolines

Nine substituted 4-aziridinoeinnolines have been prepared and subjected to anticancer screening. J. Heterocyclic Chem., 15 , 1039 (1978)     

High-spin states in165Hf

High-spin states in¹⁶⁵Hf, populated in the¹³⁰Te(⁴⁰Ca, 5n) reaction, were investigated using the Berkeley HERA -ray spectrometer array. The previously known level scheme of¹⁶⁵Hf is appreciably extended. Intrinsic configurations, band crossing frequencies and aligned angular momenta are interpreted within the frame-work of the cranked shell model. It is suggested that the alignments of the second neutron pair and of the first proton pair in¹⁶⁵Hf occur at 0.44 MeV and 0.48 MeV, respectively. The systematic trend of these alignment frequencies for the Hf isotopes and for theN=93 isotones is discussed.One of us (EMB) acknowledges a fellowship from the Hanns-Seidel Foundation. This work was supported by the Director, Office of Energy Research, Division of Nuclear Physics of the Office of High Energy and Nuclear Physics of the U.S. Department of Energy (Contract DE-AC03-76SF00098) and by the Bundesminister für Forschung und Technologie BRD (Contract 06 BN 181).     

Rapid catalytic oxidation of CO to CO(2) - On the development of a new approach to on-line oxygen isotope analysis of organic matter

A new approach to on-line oxygen isotope analysis has been developed which utilises existing elemental analyser and mass spectrometry technology to produce a sample of carbon dioxide gas for oxygen isotople analysis. The method relies on on-line high temperature pyrolysis of the sample over a carbon source followed by a rapid, non-contributive partial catalytic oxidation over nickel powder at between 550 and 600 degrees C. Initial results demonstrate both good precision (better than 0.2 per thousand) and accuracy for both cellulose and silver nitrate samples. Copyright 1999 John Wiley & Sons, Ltd.     

The synthesis and characterisation of novel ferrocenyl polyphenylenes

This work describes the synthesis and characterisation of a new series of polyphenylenes with up to four ferrocenyl moieties. The synthetic route involves the preparation of a number of novel precursors. Cyclopentadienones, generated from the two-fold Knoevenagel condensation of di-ferrocenyl propanones and diketones, are used in [2 + 4] Diels-Alder cycloadditions with appropriately substituted acetylenes. 13 is amongst the compounds isolated. It is the largest ferrocenyl-supported polyaromatic hydrocarbon (PAH) to date. Prepared via a Sonogashira cross-coupling reaction between ethynyl-Fc and iodo-HBC, it comprises a hexa-peri-hexabenzocoronene (HBC) core linked via acetylene to a ferrocenyl unit (Fc). The electrochemical and absorption properties of the ferrocenyl-polyphenylenes and the fully conjugated 13 are discussed. The NLO data for 13, determined by hyper Rayleigh scattering techniques, are compared to those of similar fulleryl-based compounds in the literature.     

A dinuclear extension to constrained heteroleptic Cu(I) systems

This article reports the synthesis and optical properties of three dinuclear, cationic copper complexes [Cu(2)(μ-dppm)(2)(μ-L)](NO(3))(2) (dppm diphenyldiphosphinomethane, L: L(A) 3,6-bis(2-pyridyl)-4,5-diphenyl-pyridazine, L(B) 3,6-bis(2-pyridyl)-4,5-di(4-pyridyl)-pyridazine and L(C) 3,6-bis(2-pyridyl)-8,9-diazafluoranthene). These were formed on the reaction of [Cu(μ-dppm)(NO(3))](2) with a series of N-donor (bppn) ligands L. The single crystal X-ray structures of [Cu(2)(μ-dppm)(2)(μ-L)](NO(3))(2)·CH(2)Cl(2) were determined and revealed that in both, the two copper atoms are held by three bridging ligands, two dppm ligands and one bppn ligand acting as a tetradentate bridge. The absorption spectra of the complexes present a MLCT [Cu → π*(N(∧)N)] band in the λ 370-425 nm region. These new complexes exhibit red-orange MLCT-based emission in the solid-state with lifetimes in the microsecond range. In oxygen-free dichloromethane solution, the complex [Cu(2)(μ-dppm)(2)(μ-L(C))](2+) has a long lifetime of 22.8 μs. The long emission lifetimes are attributed to a rigid conformation that precludes the possible distortion of the copper in the excited state.     

Mechanoresponsive Self-Assembled Perylene Bisimide Films

In this work, self-assembled amino-acid appended perylene bisimides (PBIs) have been studied that when processed into thin films change their resistivity in response to being bent. The PBIs assemble into structures in water and form thin films upon drying. These normally delicate thin films can be tolerant to bending, depending on the aggregates they form. Furthermore, the films then reversibly change their resistivity in response to this mechanical stimulus. This change is proportional to the degree of bending of the film giving them the potential to be used quantitatively to measure mechanical movement, such as in wearable devices.