No abstract

The essential trace element copper plays a key role in living systems. Its metalloproteins are involved in various reactions. The IT ononuclear blue copper type‐1 proteins take, part in electron transfer processes. Type‐2 proteins can either act as oxidases, oxygenases, dioxygenases, or superoxide dismutases, containing one copper core. Dinuclear copper centers of Type‐3 proteins are the oxygen transport system hemocyanin, oxidases and oxygenases. Due to this variety of functions copper deficiency and also abundance can cause severe damage of any life form.

The platina‐β‐diketones [Pt2{(COR)2H}2(μ‐Cl)2] (1, R = Me a, Et b) react with phosphines L in a molar ratio of 1 : 4 through cleavage of acetaldehyde to give acylplatinum(II) complexes trans‐[Pt(COR)Cl(L)2] (2) (R/L = Me/P(p‐FC6H4)3 a, Me/P(p‐CH2=CHC6H4)Ph2 b, Me/P(n‐Bu)3 c, Et/P(p‐MeOC6H4)3 d). 1 a reacts with Ph2As(CH2)2PPh2 (dadpe) in a molar ratio of 1 : 2 through cleavage of acetaldehyde yielding [Pt(COMe)Cl(dadpe)] (3 a) (configuration index: SP‐4‐4) and [Pt(COMe)Cl(dadpe)] (configuration index: SP‐4‐2) (3 b) in a ratio of about 9 : 1. All acyl complexes were characterized by 1H, 13C and 31P NMR spectroscopy. The molecular structures of 2 a and 3 a were determined by single‐crystal X‐ray diffraction. The geometries at the platinum centers are close to square planar. In both complexes the plane of the acyl ligand is nearly perpendicular to the plane of the complex (88(2)° 2 a, 81.2(5)° 3 a).

Four different disulfides, [2,2′‐dithiobis‐(2‐mercaptoacetophenone)]‐4‐triphenylmethylthiosemicarbazone (1), [5,5′‐dithiobis‐(4‐formyl‐3‐methyl‐1‐phenylpyrazole)]‐4‐triphenylmethylthiosemicarbazone (2), bis[1‐(2‐mercaptophenyl)‐2‐(4‐(1‐phenyl‐3‐methyl)pyrazole)‐azaethene]di‐sulfide (3) and bis[1‐phenyl‐2‐(4‐(1‐phenyl‐3‐methyl‐5‐mercapto) pyrazole)‐azaethene]disulfide (4) were synthesized by Schiff base reactions. Their electrochemical behaviour was examined by cyclic voltammetry. The results show low potentials for the disulfide reduction so that these compounds are suitable for the syntheses of tridentate thiolate ligands from disulfides by electrochemical cleavage. In addition compounds 2 and 4 were characterized by X‐ray structure determination. The structures show significant differences of the S—S bonds and angles as compared to other disulfides without bulky substituents.

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