C.A. McAuliffe

The relationship of some copper (II) complexes of facultative tetrathioethers to the coordination environment in the “blue” copper proteins☆

The facultative potentially tetradentate thioether ligands 1,2-bis(methylthioethylthio)ethane (2,2,2), 1,3-bis(2-methylthioethylthio)propane (2,3,2) and 1,2-bis(3-methylthiopropylthio)ethane (3,2,3) react with copper(II) salts to form Cu2(2,2,2)Cl4, Cu3(ligand)X6 (ligand = 2,3,2 and 3,2,3 X = Cl; ligand = 2,2,2 2,3,2 and 3,2,3 X = Br), and Cu(ligand)(ClO4)2. The stoichiometry and structures of these complexes are discussed in terms of the steric demands of the ligand and the nature of the halide. The [Cu(2,3,2)(ClO4)] ClO4 and [Cu(3,2,3)(ClO4) [ClO4 complexes have electronic spectra which exhibit the intense 600 nm band characteristic of the blue copper proteins. In fact, the spectrum of [Cu(2,3,2)(ClO4)]ClO4 is very similar to that of pseudomonas aeroginosa azurin.

Some platinum(II) complexes of DNA bases and nucleoside

Abstract The syntheses of [Pt(adenine)X 2 ] 2H 2 0 (X = Cl, [Pt(adenosine)I 2 ] . 2H 2 0, [Pt(guanosine)I 2 ], [Ptt. (guanine)I 2 ] and [Pt(cytosine)I 2 ] are reported. Infrared, electronic and proton n.m.r. spectra have been used to assign coordination numbers, denticity and binding tires of the ligands.

The chemistry of molybdenum and tungsten. Part XIII. Molybdenum(V) complexes of dithiocarbamates and dithioethers

Abstract Oxotrichloromolybdenum(V) reacts with dithiocarbamates. R 2 dtc − (R 2 ue605 Me 2 , Et 2 , [CH 2 ] 4 ) in acetonitrile at room temperature with cleavage of the terminal molybdenum-oxygen bond to yield [Mo(R 2 dtc) 4 ] + , isolated as the chloride or tetraphenylborate salts; infrared spectra indicate bidentate coordination by the ligands, and these complexes appear to have dodecahedral geometry. From this same reaction can be isolated the dimeric [Mo 2 O 4 (R 2 dtc) 2 ] species which contain a double Moue5f8Oue5f8Mo bridges as well as terminal Moue5fbO bonds, and also the [Mo 2 O 3 (Et 2 dtc)] complex containing a single Moue5f8Oue5f8Mo bridge and two terminal Moue5fbO linkages. With a series of dithioethers oxotrichloromolybdenum(V) yields [MoO(ligand)Cl 3 ], but the ability to complex depends critically on the structure of the dithioether. The structures of these complexes have been assigned with the aid of vibrational, electronic and electron paramagnetic resonance spectroscopy.

Coordination complexes containing multidentate ligands. : Part XIII. Nickel(II) and P. Rhodium(III)complexes of tetradentate diamine-dithioether ligands

Abstract The preparation of four open-chain diarmine-dithioether ligands is described: o-H 2 NC 6 H 4 ,S ⌢ SC 6 H 4 NH 2 -o (RN= -CH 2 CH 2 -, -CH 2 CH 2 CH 2 -, -CH 2 CH 2 CH 2 CH 2 -, and cis -CHCH-). These form six-coordinate pseudo-octahedral trans -[NiLX 2 ] (X = Cl, Br, I, NCS) complexes, which exhibit varying degrees of tetragonal distortion but which is least for the ligand with the C 2 C 3 C 2 carbon backbone sequence between the four donors. The parameters D xy q D z q and Dt are evaluated and discussed in relation to changes in L and X. Rhodium(III) salts do not form simple to monomeric adducts, but Rh 4 L 3 Cl 12 can be readily isolated; this phenomenon it discussed.

In vivo properties of some new cis-platinum complexes containing 7-azaindole ligands

Abstract Toxicity data and some preliminary antitumor testing results are reported for the new complexes cis-PtLX 2 (L = 1H-pyrrolo[2,3-b]pyridine, (7-azaindole); X 2 = Cl 2 , I 2 oxalate). Although these complexes have the cis-PtN 2 X 2 configuration recognised as desirable for effective antitumor behavior, no significant antitumor properties were observed against a number of primary screens; although interesting toxicity differences were observed between the three compounds.

Mass spectral studies of some dithioethers and diamine-dithioethers

Abstract The mass spectra of bis(phenylthio)methane, 1,2-bis(phenylthio)ethane, 1,3-bis(phenylthio)propane, 1,6-bis(phenylthio)hexane, 1,8-bit(phenylthio)octane, cis -1,2-bis(phenylthio)ethylene, o-phenylenebis(phenylthioether), some methyl-substituted analogues, and some tetradentate diamine-dithioethers are reported. The fragmentation patterns are illustrated and discussed with respect to differences between the ligands and the fragments derived from different ligands. The completely aliphatic ligands exhibit a complex fragmentation of α and β-cleavages with and without hydrogen atom migration. A number of novel sulphur- and nitrogen-containing heterocycles have been detected.

The chemistry of molybdenum and tungsten. Part XII. Molybdenum(V) and tungsten(V) complexes of nitrogen-sulphur chelating ligands. Facile amine deprotonations

Abstract The chelating ligands 1,2-di(o-aminobenzenethio)ethane, cis-1,2-di(o-aminobenzenethio)ethylene, 1,3-di(o-aminobenzenethio)propane and 1,4-di(o-aminobenzenethio)butane react with MOCl3(THF)2 (M = Mo, W) to form the [MOCl1(ligand)]2 complexes in which the ligand is a zwitterion, having transferred a proton from one amine group to the other. The simpler o-aminobenzenethiol reacts with MoOCL3(THF)2 to form [MoOCl3(ligand)3]. E.p.r., infrared and electronic spectra, as well as magnetic moments and conductivity data are discussed.

Interactions of platinum complexes, peptides, methionine and dehydrogenases

Eight platinum-methionine complexes have been investigated as inhibitors of the alcohol (EC 1.1.1.1) and lactate (EC 1.1.1.27) dehydrogenase systems. While only one complex, Pt(Met)Cl2, had two halogen ligands on the platinum, all the complexes were able to inhibit both enzyme systems. Of the various methionine and histidine containing peptides evaluated, the dipeptide Met-Met gave the best protection against inhibition by N-alkyl-substituted ethylenediamine-platinum complexes. The histidine containing peptides gave a slight protection against the inhibition by beta-[Pt(Met)(NH3)Cl]Cl. Thus it appears that in the enzyme systems studied, the methionine acts as a strong ligand for platinum.

A proposed mechanism relating the antitumor behavior of cis-platinum amine complexes to their inhibition of a model enzyme

The twenty-four hour inhibition of m-malate dehydrogenase (E.C. 1.1.1.37) by various complexes of cis-platinum(II) and cis-platinum(IV) was measured as a function of the platinum concentration. It was observed that increased alkylation of the amine groups of Pt(II) and to a lesser degree of Pt(IV) decreased the activity consistently. It was also observed that the Pt(IV) analogues inhibit the enzyme to about an order of magnitude greater than the Pt(II) complexes. These phenomena will be interpreted.

The coordination chemistry of manganese(II). Part 13 [1]. The synthesis of manganese(II) selenocyanate and its complexes with oxygen, sulphur, nitrogen and phosphorus donor atoms

Abstract Manganese(II) selenocyanate has been successfully prepared from manganese(II) chloride and potassium selenocyanate under strictly anhydrous conditions. The infrared and electron spin resonance spectra of manganese(II) selenocyanate differ significantly from those of the analogous manganese(II) thiosyanate salt. Several 1:1 Mn(ligand)(NCSe) 2 (ligand = EtOH, PPh 3 , PPhMe 2 ), 1:2 Mn(ligand) 2 (NCSe) 2 (ligand = tetrahydrofuran, THF), and 1:4 Mn(ligand) 2 (NCSe) 2 (ligand = OPPH 3 ) complexes have been prepared and characterised by spectroscopic and magnetic measurements. The monomeric Mn(THF) 3 (NCSe) 2 appears to have a trans trigonal bipyramidal structure, as predicted by Norbury. The Mn(ligand)(NCSe) 2 (L = PPh 3 , PPhMe 2 ) complexes show no tendency to coordinate dioxygen.