Correspondence of RuIIIRuII and RuIVRuIII Mixed Valent States in a Small Dinuclear Complex

The diruthenium(III) compound [(μ‐oxa){Ru(acac)₂}₂] [ 1 , oxa^2?=oxamidato(2?), acac^?=2,4‐pentanedionato] exhibits an S=1 ground state with antiferromagnetic spin‐spin coupling (J=?40 cm^?1). The molecular structure in the crystal of 1? 2 C₇H₈ revealed an intramolecular metal–metal distance of 5.433 Å and a notable asymmetry within the bridging ligand. Cyclic voltammetry and spectroelectrochemistry (EPR, UV/Vis/NIR) of the two‐step reduction and of the two‐step oxidation (irreversible second step) produced monocation and monoanion intermediates (K_c=10^5.9) with broad NIR absorption bands (ε ca. 2000 M ^?1 cm^?1) and maxima at 1800 ( 1 ^?) and 1500 nm ( 1 ⁺). TD‐DFT calculations support a Ru^IIIRu^II formulation for 1 ^? with a doublet ground state. The 1 ⁺ ion (Ru^IVRu^III) was calculated with an S=3/2 ground state and the doublet state higher in energy (ΔE=694.6 cm^?1). The Mulliken spin density calculations showed little participation of the ligand bridge in the spin accommodation for all paramagnetic species [(μ‐oxa){Ru(acac)₂}₂]ⁿ, n=+1, 0, ?1, and, accordingly, the NIR absorptions were identified as metal‐to‐metal (intervalence) charge transfers. Whereas only one such NIR band was observed for the Ru^IIIRu^II (4d⁵/4d⁶) system 1 ^?, the Ru^IVRu^III (4d⁴/4d⁵) form 1 ⁺ exhibited extended absorbance over the UV/Vis/NIR range.     

Synthesis of new azetidinonyl/thiazolidinonyl quinazolinone derivatives as antiparkinsonian agents

Several 3-amantadinyl-2-[(2-substituted benzylidenehydrazinyl)methyl]-quinazolin-4(3H)-ones (5a–5l) were prepared by the reaction of 3-amantadinyl-2-hydrazinylmethyl substituted quinazolin-4(3H)-ones (4a–4b) with various substituted aromatic aldehydes. Cycloaddition of compounds (5a–5l) with thioglycolic acid in the presence of anhydrous zinc chloride yielded 3-amantadinyl-2-[((substitutedphenyl)-4-oxo-thiazolidin-3-yl)methylamino]-quinazolin-4(3H)-ones (6a–6l). Compounds 5a–5l on further reaction with chloro acetyl chloride in the presence of triethylamine gave 3-amantadinyl-2-[((substitutedphenyl)-3-chloro-2-oxo-azetidin-1-yl)methylamino]-quinazolin-4(3H)-ones (7a–7l). The compounds 5a–5l, 6a–6l and 7a–7l were screened for their antiparkinsonian activity. The most active compound was 6g i.e. 3-amantadinyl-6-bromo-2-[((3,4-dimethoxyphenyl)-4-oxo-thiazolidin-3-yl)methylamino]-quinazolin-4(3H)-ones. Structures of the newly synthesized compounds were established on the basis of elemental and spectral (IR, ¹H NMR and mass) analysis.     

Synthesis and biological evaluation of some new substituted benzoxazepine and benzothiazepine as antipsychotic as well as anticonvulsant agents

Various 2-((2-((5-benzylideneamino)-1,3,4-oxa/thiadiazol-2-yl)methyl)hydrazinyl) methyl)benzo[b][1,4]oxa/thiazepin-4(5H)-ones (4a–4l), 2-((2-((5-(4-oxo-2-substitutedphenyl thiazolidin-3-yl)-1,3,4-oxa/thiadiazol-2-yl)methyl)hydrazinyl)methyl)benzo [b] [1,4]oxa/thiazepin-4(5H)-ones (5a–5l) and 2-((2-((5-(3-chloro-2-(substitutedphenyl)-4-oxoazetidin-1-yl)-1,3,4-oxa/thia diazol-2-yl)methyl)hydrazinyl)methyl)benzo[b][1,4]oxa/thiazepin-4(5H)-ones (6a–6l) have been synthesized. The structures of these compounds have been established by elemental (C, H, N) and spectral (IR, ¹H-NMR and Mass) analysis. The synthesized compounds were screened for their antipsychotic and anticonvulsant activities. Compound 5l was found to be the most active compound of this series.     

Application of tracer technique in remediation of Sr(II) from simulated low level radioactive waste

Journal of Radioanalytical and Nuclear Chemistry - Activity concentrations of natural (40K, 226Ra, 228Ra, 232Th, 238U) and artificial (134Cs, 137Cs) radionuclides were measured in powdered milk...     

Indium triflate promoted one-pot multicomponent synthesis of structurally diverse 3-amino-imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridines

An efficient, mild, and expeditious synthetic protocol has been developed for the synthesis of structurally diverse 3-amino-imidazo[1,2-a]pyridines, involving a three-component, one-pot cyclocondensation reaction of 2-aminobenzothiazole/2-aminoazines, ethyl isocyanoacetate/tert-butyl isocyanides, and pyrazole-3(4)-carbaldehyde/substituted aromatic carbonyl compounds in 45 min. using In(OTf)\(_{3}\) as a catalyst in toluene. Mild reaction conditions, high atom economy, operational simplicity, short reaction time, and structural diversity with high product conversion are among the advantages of the present synthetic protocol.     

Reactions of Dinitrogentrioxide with Rhodium(I) Complexes and with Rhodiumtrichloride trihydrate in presence of triphenylphosphine and triphenylarsine

Dinitrogen-trioxide reacts with rhodium(I) complexes and with rhodium trichloride trihydrated in presence of triphenylphosphine and triphenylarsine to give rhodium(III) nitrosylnitro complexes and rhodium(III) nitrosyl complexes which are characterized by ir spectra, magnetic measurement and elemental analyses.     

Spectrophotometric determination of osmium with 2R-acid in the presence of other platinum metals

Osmium(VIII) produces two coloured species with lambda(max) 680 nm (green) and 530 nm (red) with excess of 2-amino-8-naphthol-3,6-disulphonic acid in aqueous solution. The green complex is stable between pH 2.5 and 8.0 and the red complex between pH 11.0 and 12.0. The effects of temperature and time, reagent concentration, optimum conditions for the spectrophotometric determination of trace amounts of osmium, and other variables, have been studied at pH 11.5. At this pH, other platinum metals do not interfere. The sensitivity of the colour reaction is 0.2 microg/cm(2) and the system conforms to Beer's law over a concentration range of 1.5-10 microg of osmium.     

Thionitrosyl Complexes of Ruthenium and Osmium

The ruthenium trichloride hydrate and osmium tricholide react with (NSCl)₃ in presence of triphenylphosphine and triphenylarsine to give thionitrosyl complexes M(NS)Cl₃L₂ (M) ? Rn, or Os; L ? PPh₃ or AsPh₃.     

Sectrophotometric determination of vanadium(V) with 7-amino-1-naphthol-3,6-disulphonic acid

Summary Vanadium(V) reacts with 7-amino-1-naphthol-3,6-disulphonic acid (2 R-acid) in the ratio 21, forming a red coloured chelate having maximum absorbance at 470 nm. The composition of the chelate has been found by the continuous variations and the mole ratio methods. The system obeys Beer's law between a range of 1.72 to 30.9 p. p. m. of vanadium and the sensitivity is 0.17g/cm² at pH 2.0, The reagent is found to be fairly selective for vanadium.

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Zusammenfassung Vanadin(V) reagiert mit 7-Amino-l-naphthol-3,6-disulfonsäure im Ver-hältnis 21 und bildet ein rotes Chelat mit dem Absorptionsmaximum bei 470 nm, dessen Zusammensetzung nachJob bestimmt wurde. Zwischen 1,72 und 30,9 ppm V ist das Beersche Gesetz erfüllt. Die Empfindlichkeit beträgt 0,17g/cm² (Sandell) bei pH 2,0. Das Reagens ist für Vanadin ziemlich selektiv.