Electrochemistry of a labile average-valence dicopper system

Electrochemical studies on an average-valent dicopper cryptate demonstrate the existence of a solvent-assisted disproportionation in acetonitrile, which is absent in water. The existence of this process was confirmed via absorption spectroscopy, which allowed the evaluation of thermodynamic parameters. The disproportionation equilibrium is enthalpically controlled, and the results suggest an upper limit for the bond energy of the one-electron Cu-Cu bond of 200 kJ mol(-1).     

Diffuse optical measurement of blood flow in breast tumors

Blood flow contrast between tumor and normal tissues in patients with malignant and benign breast cancer was measured by diffuse optical correlation methods. The measurements were carried out with a hand-held optical probe that was manually scanned over the tumor-bearing breast. Increased blood flow was observed in tumor regions relative to healthy tissue, and control subjects did not exhibit significant blood flow heterogeneity. The measurements introduce a new optical contrast for diffuse optical mammography.     

Über die Umsetzung des Nα-Tosylglycinäthylester-isonicotinoylhydrazons mit Hydrazin und Hydrazinabkömmlingen

Zusammenfassung N-Tosylglycinäthylester-isonicotinoylhydrazon (1) reagiert vorwiegend unter Hydrazinolyse sowohl der C,N-Doppelbindung wie auch der Esterbindung zum unbeständigen Hydrazidin2, das sich in bekannter Reaktion zu4 und5 umsetzt.Eine durch ausschließliche Hydrazinolyse der Esterbindung von1 zu postulierende Acylhydrazidinzwischenstufe3 ist in Form des N⁴-Amino-1,2,4-triazols6 nachweisbar. Es werden ferner die ähnlich verlaufenden Reaktionen von Methyl-, N,N-Dimethyl- und Benzylhydrazin mit1 beschrieben.Phenylhydrazin, p-Tolylhydrazin, p-Chlor- und p-Brom-phenylhydrazin reagieren mit1 unter Bildung der N¹,N⁵-diarylsubstituierten Formazane11 b–d und der am N⁴-arylaminosubstituierten 1,2,4-Triazole12 a–d. Im Gegensatz hierzu wird mit p-Nitrophenylhydrazin das Tosylglycinäthylester-p-nitrophenylhydrazon (13 e) erhalten.

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The reaction of N-tosylglycine ethyl ester isonicotinoylhydrazone with hydrazine and hydrazine derivatives

N-Tosylglycine ethyl ester isonicotinoylhydrazone (1) undergoes hydrazinolysis both of the C,N double bond and of the ester bond to yield as major product the unstable hydrazidine2, which reacts in a known manner to yield4 and5.An acyl hydrazidine3 postulated as an intermediate formed by hydrazinolysis of the ester bond alone can be isolated in the form of N⁴-Amino-1.2.4-triazole (6). The analogous reactions of methyl-, N.N-dimethyl- and benzylhydrazine with1 are also described.Phenylhydrazine, p-tolylhydrazine, p-chloro- and p-bromophenylhydrazine react with1 to form the N¹,N⁵-diaryl substituted formazans11 b–d and the N⁴-arylamino-1.2.4-triazoles12 a–d. With p-nitrophenylhydrazine, however, the tosylglycine ethyl ester-p-nitrophenylhydrazone is obtained.