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The photoelectron(PE)spectrum of tricyclo[3.1.0.02,6] hex-2-ene(benzvalene 1) has been recorded. The first four bands in the PE spectrum of 1 can be assigned to transitions to 2B2, 2A1, 2A2 and 2B1 states of 11. This assignment is discussed in terms of the results of semiempirical and ab initio calculations on 1. Furthermore the highest occupied MO's of 1 are derived qualitatively from an interaction diagram between a distorted bicyclobutane and an ethylene moiety. 相似文献
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The molybdenum complexes of Schiff base ligands viz. [MoO2LH2O] where L1 = tris(hydroxymethyl)(salicylide-neamino)methane, L2 = tris(hydroxymethyl)(2,3-dihydroxybenzylideneamino)methane and L3 = tris(hydroxymethyl)(2,3,4-trihydroxybenzylideneamino)methane have been synthesized and characterized by spectroscopic and electrochemical techniques. The X-ray crystal structure of the complex [MoO2L1H2O] reveals a distorted octahedral geometry with one ligand and a water molecule coordinated to the MoO2 center. No previous complex of this type contains a coordinated water molecule. The complex undergoes an oxotransfer in the presence of Bu3P to form a -oxobridged molybdenum(V,V) dimer. This rules out Mo—S coordination as a prerequisite for oxotransfer in such molybdenum(VI) complexes. 相似文献
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S. Recknagel P. Brätter A. Tomiak U. Rösick 《Fresenius' Journal of Analytical Chemistry》1993,346(6-9):833-836
Summary An analytical procedure for the determination of Se, as well as of other trace elements of clinical interest, in undiluted blood serum samples is presented. This procedure allows the on-line wet ashing of the sample, the hydride generation and the determination of the SeH2 formed in one step. For this purpose, carrier solution and the injected sample (300 l) were merged with an acid stream (80% H2SO4, 12% HClO4, 8% HNO3) and passed through a reaction coil heated up to 240°C. To increase the dispersion, the wet digestion was carried out in an ultrasonic field. After trapping of the gas bubbles, 5 mol/l HCl and 0.053 mol/l NaBH4 solutions were added via T-junctions for Se-hydride generation. The nebulizing system of the ICP-OES was used as gas/liquid separator. The hydride was swept from the spray chamber into the plasma by an argon gas flow with droplets containing other sample constituents. This allows the simultaneous determination of other trace elements of clinical interest, for example Fe, Cu and Zn. The relative detection limit for Se in blood serum was 5 g/l. The quality of the developed procedure was verified in two ways: by measuring SRM Seronorm 116 and by comparing the results for different serum samples with the results obtained with ETAAS. Our results were in good agreement in both cases.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday 相似文献
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