Phototauntomerism of o-nitrobenzyl compounds: o-quinonoid aci-nitro species studied by matrix isolation and DFT calculations

Photolyses of 2-nitrobenzyl methyl ether and 2-nitrotoluene with 254 nm light have been investigated in Ar and N2 matrices at 12 K, and have been found to give o-quinonoid aci-nitro species as the primary photoproducts, along with other products. The o-quinonoid species have UV absorptions at relatively long wavelengths (λmax at 385–430 nm) and undergo facile secondary photolysis when irradiated in these absorption bands. By means of this selective photolysis, fairly complete IR spectra of the o-quinonoids have been obtained. Comparison of the matrix IR spectra of these species with simulated spectra computed using density functional theory (DFT) has confirmed the identity of these reactive intermediates. Moreover, detailed analysis of the fit between the computed and experimental IR spectra has allowed the specific stereoisomers generated to be identified with reasonable confidence. Computations have also been made of the relative energies of the starting compounds, intermediate o-quinonoid isomers and the possible secondary products, together with the transition states connecting them. The results of these computations indicate that the observed stereoisomer of each of the o-quinonoid species cannot arise by photoinduced H-atom transfer followed by isomerizations on the electronic ground-state surfaces, since the energy barriers for reversion to starting compounds are substantially lower than those for the necessary isomerizations. It is therefore concluded that H-atom transfer and conformational interconversion occur in an electronic excited state

The effects of anion and cation substitution on the ultrafast solvent dynamics of ionic liquids: A time-resolved optical Kerr-effect spectroscopic study

Ultrafast solvent dynamics of room-temperature ionic liquids have been investigated by optical heterodyne-detected Raman-induced Kerr-effect spectroscopy ~OHD-RIKES! by studying the effects of cation and anion substitution on the low frequency librational modes. The spectra of two series of imidazolium salts are presented. The first series is based on the 1-butyl-3-methylimidazolium salts @bmim#1 containing the anions trifluoromethanesulfate @TfO#2, bis~trifluoromethanesulfonyl!imide @Tf2N#2, and hexafluorophosphate @PF6#2. The second series is based on @Tf2N#2 salts containing the three cations 1-butyl-2,3-dimethylimidazolium @bmmim#1, 1-methyl-3-octylimidazolium @omim#1, and @bmim#1. It is found in all five samples that the signal is due to libration of the imidazolium ring at three frequencies around 30, 65, and 100 cm21 corresponding to three local configurations of the anion with respect to the cation

Ionic liquids: novel media for characterisation of radical ions

The novel application of ionic liquids as media for radiolytic generation and UV−vis−NIR spectroscopic characterization of radical ions is described. The redox properties of neat 1-butyl-3-methylimidazolium salts and their aqueous solutions have been investigated by means of pulse radiolysis. Furthermore, ionic liquids prove to be ideal media for the simultaneous generation of radical cations and anions. The radical cations generated from 1-methyl-1,4-dihydronicotinamide, a structural analogue of NADH, have been spectroscopically characterized under matrix conditions for the first time

OLS versus ML estimation of non-market resource values with payment card interval data

Ethylene oligomerisation in ionic liquids gives predominately alk-1-ene products with better reactivity and selectivity than in conventional solvents; turnover frequencies are correlated with polarity data obtained using solvatochromic dyes.</p

Raman spectroscopic evaluation of molecular orientation in polysulfone

In this paper, we present for the first time a Raman spectroscopic method for the determination of molecular orientation in uniaxially oriented polysulfone (PSU)

Azabenzocycloheptenones. Part 20. Synthesis and utilisation of 4-amino-1,2,3,4-tetrahydro-1(1H)-benzazepines

1,2,3,4-Tetrahydro-6- and -7-methoxy-4-oxo-1-(p-tolylsulfonyl)quinolines and 1-ethoxycarbonylmethyl-1,2,3,4-tetrahydro-7-methoxy-4-oxoquinoline have been ring-expanded in two steps to 2,3,4,5-tetrahydro-7- and -8-methoxy-4-oxo-1-(p-tolylsulfonyl)-1H-1-benzazepines and 1-ethoxycarbonylmethyl-2,3,4,5-tetrahydro-8-methoxy-4-oxo-1H-1-benzazepine. Redn. of the oximes gives 4-amino-2,3,4,5-tetrahydro-7-methoxy-1-(p-tolylsulfonyl)-1H-1-benzazepine, 4-amino-2,3,4,5-tetrahydro-8-methoxy-1H-1-benzazepine, and 4-amino-1-ethoxycarbonylmethyl-2,3,4,5-tetrahydro-8-methoxy-1H-1-benzazepine. From these, several N-substituted and N,N-disubstituted compds. have been obtained and 3-amino-2,3,4,5-tetrahydro-1-(p-tolylsulfonyl)-1H-1-benzazepine has been made by similar means. Two routes are described to 2,3,4,5-tetrahydro-8-methoxy-5-oxo-1-(p-tolylsulfonyl)-1H-1-benzazepine which is converted to 2,3,4,5-tetrahydro-8-methoxy-4-methoxyimino-5-oxo-1-(p-tolylsulfonyl)-1H-1-benzazepine and thence to 5-[2-(ethoxycarbonyl)ethynyl]-2,3,4,5-tetrahydro-5-hydroxy-8-methoxy-4-methoxyimino-1-(p-tolylsulfonyl)-1H-1-benzazepine and 5-[2-(ethoxycarbonyl)ethyl]-2,3,4,5-tetrahydro-5-hydroxy-8-methoxy-4-methoxyimino-1-(p-tolylsulfonyl)-1H-benzazepine. Redn. of 2,3,4,5-tetrahydro-8-methoxy-4-oximino-5-oxo-1-(p-tolylsulfonyl)-1H-1-benzazepine in two steps gives both cis- and trans-4-acetamido-2,3,4,5-tetrahydro-5-hydroxy-8-methoxy-1-(p-tolylsulfonyl)-1H-1-benzazepines which are sep. deacetylated and cyclised with Et chloroacetate to cis- and trans-2,3,4,4a,5,6,7,11b-octahydro-9-methoxy-3-oxo-7-(p-tolylsulfonyl)[1,4]oxazino[3,2-d][1]benzazepine. By similar methodol. cis- and trans-2,3,4,5-tetrahydro-5-hydroxy-8-methoxy-4-propionamido-1-(p-tolylsulfonyl)-1H-1-benzazepines have been obtained, sepd. and the latter reduced to trans-2,3,4,5-tetrahydro-5-hydroxy-8-methoxy-4-(n-propylamino)-1-(p-tolylsulfonyl)-1H-1-benzazepine. In three steps the latter is converted to trans-2,3,4,4a,5,6,7,11b-octahydro-9-methoxy-4-(n-propyl)-7-(p-tolylsulfonyl)[1,4]oxazino[3,2-d][1]benzazepine

Surgical education and training in Australia and New Zealand

Surgical education for medical students in Australia and New Zealand is provided by 19 universities in Australia and 2 in New Zealand. One surgical college is responsible for managing the education, training, assessment, and professional development programs for surgeons throughout both countries. The specialist surgical associations and societies act as agents of the college in the delivery of these programs, the extent of which varies among specialties. Historically, surgical training was divided into basic and specialist components with selection required for each part. In response to a number of factors, a new surgical education and training program has been developed. The new program incorporates a single merit-based national selection directly into the candidate's specialty of choice. The existing curriculum for each of the nine specialties has been remodeled to a competence-based format in line with the competence required to undertake the essential roles of a surgeon. New standards and criteria have been produced for accreditation of health care facilities used for training. A new basic surgical skills education and training course has been developed, with simulation playing an increasing role in all courses. Trainees' progress is assessed by workplace-based assessment and formal examinations, including an exit examination. The sustained production of sufficient competent surgeons to meet societal needs encompasses many challenges including the recruitment of appropriate graduates and the availability of adequate educational and clinical resources to train them. Competence-based training is an attractive educational philosophy, but its implementation has brought its own set of issues, many of which have yet to be resolved.John P. Collins, Ian D. Civil, Michael Sugrue, Zsolt Balogh, Mellick J. Chehad