L. Sindellari

Complexes of platinum(II) halides with dithiocarbamic esters

Abstract Platinum(II) halides form either 1:1 or 1:2 complexes with dithiocarbamic esters (R 2 NC(S)SR′). Complexes of both stoichiometries have been obtained with the ligands TMDT (R  R′  Me) and DMDTE (R  Me; R′  Et), whereas with TEDT (R  R′  Et) only the 1:1 adducts were isolated. From IR spectra the complexes of formula PtL- 2 X 2 (L = TMDT, DMDTE; X = Cl, Br, I) have a trans square planar configuration by two halide and two thiocarbonyl sulfur atoms. In the complexes of formula PtLX 2 , for which a cis square planar configuration is suggested, the ligands act probably as bidentate through either thiocarbonyl or thioether sulfur. All the complexes have been tested for cytostatic activity on KB cells.

Chemistry of the uranyl group—VI: Complexes of uranyl with hexamethylphosphoramide and urea

Abstract Some uranyl complexes with hexamethylphosphoramide (HMPA) and urea were prepared and characterized. The compounds with the former ligand have the general formula UO 2 X 2 ·HMPA (where X = (C 2 H 5 ) 2 NCSe 2 − , (C 2 H 5 ) 2 NCS 2 − or CH 3 COO − . For the acetato derivative a dimeric acetato-bridged structure is suggested. Some properties of UO 2 (NO 3 ) 2 ·2(HMPA) are also described. With the latter ligand, in addition to the complexes UO 2 (NO 3 ) 2 ·2urea and [UO 2 (urea) 4 (H 2 O)](NO 3 ) 2 already known, the novel complexes UO 2 (pycrate) 2 ·4urea and [UO 2 (CH 3 COO) 2 ·urea] n (where n is probably 2) have been prepared. All attempts to obtain urea complexes of uranyl diethyldithio- or diethyldiselenocarbamate failed and only adducts of unsatisfactory stoicheiometry were isolated.

N,N-dimethyl O-ethylthiocarbamate complexes of palladium(II) and platinum(II) halides

Complexes of formula M(DMTC)2X2 (where M = Pd, Pt; DMTC = N,N-dimethyl O-ethylthiocarbamate; X = Cl, Br, I) have been prepared and studied by visible, IR and 1H nmr spectroscopy. The ligand acts as sulfur donor towards the metal atom. The complexes have generally a trans square-planar geometry. Whereas the structure of solid Pd(DMTC)2Cl2 could not be determined, in solution a trans configuration is suggested. Cis-Pt(DMTC)2X2 (X = Cl, Br) have been also isolated, which in solution slowly isomerize to trans. The compounds have been tested for possible cytotoxic effects.

Synthesis, characterization and evaluation of biological activity of palladium (II) and platinum (II) complexes with dithiocarbamic acids and their derivatives as ligands

Abstract We report the preparation and characterization of new complexes of palladium (II) and platinum (II) with some heterocyclic containing dithiocarbamate ligands, such as piperidine-, morpholine-, and thiomorpholine-dithiocarbamate, their methyl esters and the corresponding thiouramdisulphides. These compounds have been studied through spectroscopic techniques, IR spectra, and electronic spectra, thermogravimetric and conductivity measurements. Thermal decomposition of the complexes takes place through a multi-step process involving pyrolysis of the organic moiety that leads to palladium oxide and platinum sponge respectively. All the complexes have been tested for cytostatic activity on KB cells and the most effective compounds also against L1210 and P388 cells.

Bis(9-ethylguaninium) and bis(9-ethylguanine) complexes of pt(II): preparation and crystal structures of cis-[Cl2Pt(9-EtGH2)2]CL2·2H2O and cis-[(pra)2Pt(9-EtGH)2](NO3)2 (pra n-propylamine)

The structurcs of two Pt(II) complexes cis -[Cl 2 Pt- (9-EtGH 2 ) 2 ]Cl 2 ·2H 2 O (2) and cis -[(pra) 2 Pt(9- EtGH) 2 ](NO 3 ) 2 (3) with 9-EtGH2  9-ethylguaninium cation, 9-EtGH  neutral 9-ethylguanine and pra  n-propylamine, are reported. Pt binding in both compounds is through N7 of the purine rings which in the case of 2 are protonated at N3. The guanines adopt head—tail orientations both in 2 and 3. The compounds crystallize in the space group P 2 1 / c with the following cell dimensions: a = 14.214(3) (2), 7.990(4) (3), b = 12.197(3) (2), 38.292(6) (3), c = 15.525(3) (2), 10.271(4) (3) A, β = 114.59(3) (2), 103.67(5)° (3), Z = 4.

Synthesis and in vitro cytostatic activity of platinum(II) nitrate complexes with propan-1-amine

Abstract The platinum(II) nitrate complexes cis- and trans - [PtPra 2 (NO 3 ) 2 ], [PtPra 3 X]NO 3 and [PtPra 4 ](NO 3 ) 2 · n H 2 O (Pra=propan-l-amine; X=CL, Bror NO 3 ; n = O or 2) have been prepared and characterized by infrared and 1 H NMR spectroscopy and by thermal analysis (TG, DTG and DTA). The complexes have been tested for in vitro cytostatic activity against KB tumor cells. Their activity follows the order cis -[PtPra 2 (NO 3 ) 2 ] > [PtPra 3 Cl]NO 3 > [PtPra 3 (NO 3 )]NO 3 > trans -[PtPra 2 (NO 3 ) 2 ] > [PtPra 4 ]- (NO 3 ) 2 . The last species is inactive, whereas the activity of the cis adduct compares weil with that of cis - [Pt(NH 3 ) 2 Cl 2 ] in analogous conditions.

N-substituted ethylcarbamate adducts of thoriumm tetrachloride, uranium tetrachloride and uranyl nitrate

Abstract Thorium tetrachloride forms 1:3 complexes with N,N-dimethylethylcarbamate (DMU) and with N-methylethylcarbamate (MU), whereas uranium tetrachloride forms complexes of formula UCl4·2DMU and UCl4·2MU·THF (where THF = tetrahydrofuran) respectively. Urnyl nitrate forms 1:2 complexes with either DMU or MU. The IR spectra show that in all the adducts both the ligands coordinate the metal through the carbonyl oxygen atom. The uranyl complexes exhibit their most usual six-coordination around the central monodentate molecules of the organic ligand. In the uranium and thorium tetrachloride adducts with MU the chlorine atoms seem to act as hydrogen bond acceptors with respect to the NH groups of the ligand.1 H nmr spectra are reported and discussed.

Chemistry of the uranyl group—V: Some uranyl complexes with trimethylamine oxide

Abstract Some uranyl complexes with several anionic bidentate ligands and trimethylamine oxide ( L ) were prepared and characterized. The diethyldithiocarbamato (DTC) and the diethyldiselenocarbamato (DSC) derivatives have the general formula UO 2 X 2 L (where X = DTC or DSC). An acetato complex of formula [UO 2 (OAc) 2 · L .H 2 O] 2 was also isolated. Furthermore by reaction of uranyl nitrate hexahydrate with the ligand L , two compounds were obtained of formula UO 2 (NO 3 ) 2 ·2 L and UO 2 (NO 3 )) 2 ·4 L , respectively. As expected the first complex has an eight-coordinated configuration with the two nitrato-groups both chelate to the uranium atom; we suggested for the other complex a salt-like formulation from i.r. spectral evidences. In addition the preparation and the properties of UO 2 (DSC) 2 ·(C 6 H 5 ) 3 PO and UO 2 (DSC) 2 ·(C 6 H 5 )AsO are reported.

Platinum-dihalide complexes with N-alkyl O-ethylthiocarbamates

SummaryThe thiocarbamic esters (L)ETC(EtOSCNHEt) and PTC (EtOSCNHPr) act as sulphur donors towards platinum halides, yielding the cis-[Pt(L)2Cl2], trans-[Pt(L)2Br2], [Pt(L)3X]X (X = Cl or Br) and [Pt(L)4]X2 (X = Cl, Br or I) complexes. By addition of n-hexane to platinum chloride solutions in pure ligands the 1∶6 adducts [Pt(L)4]-Cl2·2L have been isolated. The non-bonded ligand molecules are easily released to give the corresponding 1∶4 complexes. The compounds have been characterized by elemental analysis and spectroscopy. The 1∶4 and 1∶6 complexes decompose in benzene to form the 1∶3 species, except for [Pt(ETC)4]I2, which releases two ligand molecules to give trans-[Pt(ETC)2I2]. The 1∶2 and 1∶3 complexes have been tested for in vitro cytostatic activity against KB cells.

Gold(I) complexes of thio- and dithiocarbamate esters. The structure of bis(N-methyl-O-ethyl-thiocarbamate)gold(I) chloride

Abstract The complexes Au(TMDT)Br, Au(TMDT)Cl, [Au(PPh3)(TMDT)]NO3 and Au(MTC)2Cl (TMDT = N,N-dimethyl-S-methyl-dithiocarbamate, MTC = N-methyl-O-ethyl-thiocarbamate) have been prepared and characterized. The crystal structure of Au(MTC)2Cl was determined by X-ray crystallography and refined to R = 0.035 based on 2654 observed reflections. The compound is triclinic, space group P 1 , with a = 6.937(6), b = 9.439(5), c = 12.286(4) A, α = 74.16(3), β = 99.54(3), γ = 108.06(3)°. The structure consists of Au(MTC)2+ cations significantly distorted from the linear coordination, with a SAuS angle of 155.3(1)° and AuS bond distances of 2.286(2) and 2.284(2) A, and uncoordinated Cl− anions hydrogen bonded to the two MTC ligands in each cation, with NH···Cl distances of 3.04(1) A. 1H NMR spectra of the dithiocarbamate complexes are consistent with coordination of the ligand through its thiocarbonyl sulfur atom.