Thiocarbonyl Sulfur Research Articles

A study of Ru(II) complexes of some selected NS donors

A number of Ru(II) complexes of six monoacid bidentate NS donors in the form of ring substituted 4-phenylthiosemicarbazides have been synthesized and characterized by elemental analysis, conductance and magnetic susceptibility measurements as well as by various spectroscopic techniques such as UV-Vis, IR and NMR spectroscopy. All the complexes have the general formula [Ru(LH) 2X 2]· nH 2O where LH = a substituted thiosemicarbazide and X = Cl and I. From IR study the trans disposition of these two coordinated X − ions has been established. In all the complexes the ligand binds itself to the Ru(II) ion in its keto form through its thiocarbonyl sulphur atom and the nitrogen atom of the terminal −NH 2 group of the thiosemicarbazide moiety. Reactivity of these [Ru(LH) 2X 2]· nH 2O complexes towards various types of reagents like pyridine, DMF, NH 4SCN, NaHSO 3, C 6H 5CN and PPh 3 has been examined and the products have been characterized. In all these reactions ruthenium is found to retain its +2 oxidation state. Antibacterial activity of some of the Ru(LH) 2X 2· nH 2O complexes have been examined against E. coli and the corresponding minimum inhibitory concentration (MIC) values are reported.

Studies on Thioamidopyridine Complexes of some 3d Bivalent Metal Ions

Abstract Thionicotinamide (TNA) and isothicnicotinamide (ITNA) form complexes with metal (II) salts of the types Ni(TNA)2, [CuL2Cl2.H2O]2 M(ITNA)2Cl2 [M=Mn(II), Co(II), Ni(II), and Zn(II)] and [ML2(H2O)2] (NO3)2 [M=Co(II), Ni(II); L=TNA and ITNA]. The complexes have been characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility, electronic and i.r. spectral measurements. Infrared studies indicate the bidentate nature of the ligand with the bonding sites being the pyridine nitrogen and the thiocarbonyl sulphur in all the complexes except the copper(II) complexes where the ligands are behaving as monodentate bonding through sulphur only. Octahedral coordination around the metal ions has been proposed from magnetic and electronic spectral data.

Mixed chloro-, NN-dialkyldithiocarbamato-, and S-alkyl NN-dialkyldithiocarbamate complexes of platinum(II). Crystal structure of [PtCl(S2CNEt2)(MeS2CNEt)

The platinum(II) complexes [PtCl(S2CNMe2)(EtS2CNEt2)](1), [PtCl(S2CNEt2)(MeS2CNMe2)](2) and [PtCl(S2CNEt2)(MeS2CNEt2)](3) have been prepared and characterized by i.r. and 1H n.m.r. spectroscopy. The crystal and molecular structure of compound (3) has been solved by X-ray diffraction methods and refined by least squares to a final R value of 0.037. The platinum atom is bonded, in the usual square-planar arrangement, to the sulphur atoms of the bidentate –S2CNEt2 group, to the thiocarbonyl sulphur of the dithioester molecule, and to the chlorine atom. In solution the complexes release the weakly bonded dithioester molecule.

ChemInform Abstract: CATALYTIC REARRANGEMENT OF O‐CHOLESTERYL S‐ALKYL DITHIOCARBONATES TO S‐ALKYL S‐CHOLESTERYL DITHIOCARBONATES BY PHENOLS

AbstractDie nach literaturbekanntem Verfahren dargestellten Dithiocarbonate (I) lagem sich in verschiedenen Phenolen zu den entsprechenden Isomeren (II) um.

Catalytic rearrangement of O-cholesteryl S-alkyl dithiocarbonates to S-alkyl S-cholesteryl dithiocarbonates by phenols.

Phenolysis of O-cholesteryl S-alkyl dithiocarbonates gave the corresponding S-alkyl S-cholesteryl dithiocarbonates. The rearrangements obeyed first-order rate laws and the rates were affected by the acidity of the phenols. A plot of the substituent effect of the S-alkyl moiety against the Tafts σ* values was roughly linear. ortho-Substituted phenols such as 2-chlorophenol or 2, 6-dimethylphenol considerably retarded the rearrangement. The role of phenols and the reaction behavior of O-cholesteryl S-alkyl dithiocarbonates are discussed on the basis of kinetic and molecular orbital calculation data indicating that the rearrangement may proceed by specific solvation of phenols at the thiocarbonyl sulfur atom.

Complexes of platinum(II) halides with dithiocarbamic esters

Platinum(II) halides form either 1:1 or 1:2 complexes with dithiocarbamic esters (R2N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-2X2 (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 PtLX2, 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.

Adduct formation of some tris(N,N dialkyldithiocarbamato)Cr(III) complexes with iodine

Spectrophotometric studies of dichloromethane solutions containing iodine and some Cr(S 2CNR 2) 3 complexes (where R 2NCS − 2 are: OC 4H 8NCS − 2 = modtc; (C 2H 5) 2NCS − 2 = Et 2dtc; (C 6H 5CH 2) 2NCS − 2 = Bz 2dtc) have shown the formation of 1:1 adducts whose spectral features were studied and which suggested that charge-transfer interaction involving iodine and a sulphur atom of a coordinated dithiocarbamato ligand occurred. A new BASIC non-linear least-squares program which performs an optimization of the absorbance data taken at several wavelengths was devised to evaluate reliable formation constants. The thermodynamic parameters have been calculated and compared with those obtained in the same conditions as above by a reinvestigation of the known 1:1 complex formation of iodine with the corresponding tetraalkylthiuram-disulphides, where the donor site is also the sulphur atom of the thiocarbonyl group. The −ΔH° values related to the Cr(dtc) 3 · I 2 complexes are about 2 kcal lower than those of thiuram disulphides, showing a lowering of the donor strength of the thiocarbonyl sulphur as a consequence of the coordination to the metal.

Aromatic thioketone triplets and their quenching behaviour towards oxygen and di-t-butylnitroxy radical. A laser-flash-photolysis study

Results obtained using nanosecond laser flash photolysis with various exitation wavelengths (337.1–600 nm) are reported for triplet-related properties of five aromatic thioketones, namely xanthione, thioxanthione, thiobenzophenone and p,p′-dimethoxy and p,p′-bis(N,N-dimethylamino) derivatives of thiobenzophenone. The triplet yields (ϕT) of these thioketones in benzene are high (0.5–1.0) and show a dependence on excitation wavelengths. The intersystem-crossing efficiency is less than unity (0.5–0.6) when laser excitation is carried out into the second excited singlet state, S2(λex= 355 and 425 nm), but approaches unity when the excitation leads to absorption into the lowest excited singlet, S1(532 and 600 nm). The intrinsic triplet lifetimes are short (0.8–1.8 µs) and the self-quenching rate constants are in the range (2.6–7.1) 109 dm3 mol–1 s–1. Quantitative data concerning triplet–triplet absorption spectra and triplet quenching by azulene, ferrocene, β-carotene and 2,5-dimethyl-2,4-hexadiene are presented. The oxygen quenching rate constants [(2.8–9.7)× 109 dm3 mol–1 s–1] increase when electron-donating groups (methoxy and N,N-dimethyl-amino) are present in the thiobenzophenones, suggesting that charge-transfer interaction is important. The efficiency of singlet-oxygen generation in the course of the oxygen quenching of the p,p′-dimethoxythiobenzophenone triplet is unity. The stable free radical, di-t-butyl-nitroxide, quenches the thioketone triplets with unusually high rate constants [(1.4–3.3)× 109 dm3 mol–1 s–1]; this behaviour appears to be a manifestation of electron-exchange-mediated intersystem crossing (S0 [graphic omitted] T1), enhanced by strong spin–orbit coupling or spin–spin interaction associated with the thiocarbonyl sulphur atom.

Synthesis and Studies of Some Bivalent Metal Complexes of 1-p-Chlorobenzoyl-4-phenyl-3-thiosemicarbazide

Abstract The synthesis, spectra (IR, Visible), magnetic susceptibilites and conductance measurements of a series of bivalent metal complexes of the general formula [M(L-H)2]. nH2O(M = Mn(II), Ni(II), Cu(II) and Cd(II); L=p-CPTS = 1-p-chlorobenzoyl-4-plenyl-3-thiosemicarbazide and n = 1 or 2), [M(L-H)X- nH2O] (M = Co(II), Cu(II); X=Cl, Ac and n = O-3), [Co(L-H)Cl-DMF] (DMF=dimethylformamide) and [HgLCl2] are described. 1H NMR spectra of the ligand and the diamagnetic complexes are discussed. The infrared spectra show that the ligand behaves in a bidentate manner coordinating via the (1NH) and the thiocarbonyl sulphur atoms either in the keto or in the enol form to give five membered ring around the metal ion. Both magnetic and the spectral studies are in favour of an octahedral structure for the brown Co(II) complex, [Co(L-H)Cl (H2O)3], which changes to a green tetrahedral Co(II) complex, [Co(L-H)Cl-DMF], on dissolution of the brown complex in DMF. Also, the stereochemistry of Ni(II)and Cu(II) complexes ha...

ChemInform Abstract: PYRIDINIUM‐1‐THIOACYLAMINIDES

AbstractDie aus den Mesitylensulfonaten (I) zugänglichen Pyridiniumaminide (II) liefern bei der Alkylierung die E/Z‐isomeren S‐Alkylierungsprodukte (III) und (IV).

Pyridinium-1-thioacylaminides

Abstract Pyridinium-, 2-methylpyridinium-, and 2,6-dimethylpyridinium-1-thioacylaminides (5–7) were prepared from the corresponding unsubstituted pyridinium-1-aminides and methyl dithiocarboxylates in fairly good yields. The alkylation reaction of 5–7 took place exclusively on the thiocarbonyl sulfur, yielding pyridinium salts in quantitative yields. The NMR spectroscopic studies indicated that E and Z forms existed for these pyridinium salts. The thermal decomposition of 5–7 yielded the corresponding pyridine, nitrile, and sulfur in good yields.

NEW METAL COMPLEXES DERIVED FROM 1-ACETYL-TRIMETHYLAMMONIUM CHLORIDE-4-PHENYL-3-THIOSEMICARBAZIDE WITH SOME DIPOSITIVE METAL IONS

Abstract The preparation and chatacterization of some dipositive metal ion complexes derived from 1-acetyltrimethylammonium chloride-4-phenyl-3-thiosemicarbazide [(ATPTS)] Cl is reported. The solid complexes with the composition [M(ATPTS)X2] Cl.nH2 O, (M=Mn(II), Cu(II), Zn(II) and Hg(II); X=Cl, Br, 1/2SO4, Ac or NO2 and n=O-3), [M(ATPTS)X2]Cl2, (M=Ni(II), Cu(II) and Cd(II); X=Cl(Br), [Co(ATPTS) Cl(H2O)]Cl2.H2O and [Cu(ATPTS)SO4 Py2]Cl, have been characterized on the basis of elemental analyses and spectra (IR, visible and NMR), as well as magnetic and conductivity measurements. IR spectral data indicate that the ligand coordinates via the carbonyl oxygen or thiocarbonyl sulphur atoms and the appropriate hydrazide nitrogen atom to give a 5-membered chelating ring.

IRON(II, III) COMPLEXES WITHN, N'-DI(2-)PYRIDYL THIOUREA. MÖSSBAUER AND OTHER SPECTROSCOPIC STUDIES

Several iron(II, III) complexes of N, N'-di(2-)pyridyl thiourea have been synthesized. The preparation of the complexes from iron(III) salts proceeds through a reduction of iron(III) to iron(II) followed by a subsequent reoxidation. The Moumlssbauer, electronic and infrared spectra of these complexes have been measured. The results are concordant with the coordination of pyridine nitrogens and thiocarbonyl sulfur yielding polymeric complexes. A variable temperature NMR study of the free ligand shows that two conformation are accessible for it in solution at subambient temperatures.

Copper(I) and silver(I) complexes of N-methyl-rhodanine and N-amino-rhodanine

The following copper(I) and silver(I) complexes of N-methyl-rhodanine (MeRd, L) and N-amino-rhodanine (H 2NRd, L′) have been prepared and studied by infrared and conductometric methods: CuXL (X = Cl, Br, I), CuClO 4L 4, CuXL′ [X = Cl( 4 1HAc), I( 4 1DMF)], Cu 2Br 2L′ · 4 1HAc, Cu 2X 2L′ 2.55 ′> c41DMF (X = Cl, Br), CuClO 4L′ 2 · HAc, AgNO 3L, AgNO 3L′, AgClO 4L′ 2, AgClO 4L′ 2. The MeRd is coordinated through the thiocarbonyl sulphur atom and in most of its complexes through the ring-notrogen atom. The H 2NRd is coordinated through the amine nitrogen and the thiocarbonyl sulphur atoms. Most of the complexes have a tetrahedral coordination.

Metal complexes of thiophene 2-thiocarboxamide. Proton and 13C NMR, IR and electronic spectral studies

The complexes of thiophene 2-thiocarboxamide (TTCA) with some metal chlorides and bromides [M = Ni(II), Zn(II), Cd(II), Hg(II) and Cu(I)] are described. Elemental analyses, magnetic susceptibilities and conductance studies, electronic, IR, proton and 13C magnetic resonance spectra are reported. The results suggest exclusive coordination of TTCA through the thiocarbonyl sulfur. The influence of the thiophene ring on the donor properties of the thioamide are discussed.

Cobalt(II), nickel(II) and copper(II) complexes of N-amino-rhodanine

Abstract In the cobalt(II), nickel(II) and copper(II) complexes of N-amino-rhodanine (L): CuLX 2 (X = Cl, Br), ML 2 X 2 (M = Co, X = Cl, I; M = Ni, X = Cl, Br), ML 25 X 2 (M = Co, X = Br(H 2 O); M = Ni, X = I), ML 3 )ClO 4 ) 2 (M = Co, Cu), NiL 4 (ClO 4 ) 2 the ligand is bonded through the amine nitrogen atom and through the thiocarbonyl sulphur atom. Spectroscopic evidence suggests the cobalt(II) complexes have a distorted octahedral and the nickel(II) and copper(II) complexes a tetragonal coordination.

Complexes of cadmium(II) with 2,4-dithiobiuret

The cadmium(II) complexes of 2,4-dithiobiuret (Hdtb=L) : Cd 2L 3Cl 4, CdL 2X 2 (X=Br, I, ClO 4), CdL 3SO 4·H 2O and CdL 4(NO 3) 2 have been prepared and investigated by i.r. spectra. In all these complexes Hdtb is S-coordinated, principally behaving as a monodentate ligand, in some cases with a weaker interaction of the second thiocarbonylic sulphur atom. In the halide complexes the cadmium ion is six coordinated with halide bridging ions.

Zinc (II), cadmium (II) and mercury (II) complexes of 2-methyl-5-mercapto-1,3,4-thiadiazole

The following zinc (II), cadmium (II) and mercury (II) complexes of 2-methyl-5-mercapto-1,3,4-thiadiazole (HL) have been prepared and studied by conductometric, i.r. and Raman methods: MX 2·2HL (M = Zn, X = Cl, Br, I; M = Cd, Hg, X = Cl, Br), Ml 2 (M = Zn, Cd), CdL 2·HL·NH 3, HgL·NO 3, HgL 2·HL, HgL 2·NH 3. In the MX 2·2HL complexes the ligand is bonded to the metal through its thiocarbonylic sulphur atom with terminal MX bonds for the zinc and mercury and with bridging halide ions for cadmium complexes. The polymeric ZnL 2 and CdL 2 complexes have presumably an S 2N 2- and an S 2N 4-coordination, respectively. For the CdL 2·HL·NH 3 and HgL 2·HL complexes an S 3N 3-coordination may be proposed. In the HgL·NO 3 complex the nitrate ion is coordinated presumably with an S, O, N 2 coordination.

N-aminorhodamne complexes of palladium(II), palladium(IV) and platinum(II)

TheN-aminorhodanine (L) complexes: PdLX, (X = Br or I), ML1.5Cl2 (M = Pd or Pt), PtL2X2 (X = Br, I or ClO4), PdL3(ClO4)2, PdL1.5Cl4 and PdL3(ClO4)4 have been prepared and investigated. The ligand is bonded to the metal ion through the aminic nitrogen atom as monodentate or through this atom and the thiocarbonylic sulphur atom when it acts as chelating or bridging ligand. The carbonylic oxygen atom is never coordinated.

Hindered rotation of some substituted thioureas in complexes of chromium and tungsten carbonyls

We describe a procedure for the preparation of various metal thiourea complexes of the type [M(CO) 5L] in which M  Cr or W and L  TU (thiourea) , TMTU (tetramethylthiourea), DptTU (NN′-di-p-totyl thiourea); DtBTU = (NN′-di-t-butyl thiourea). Structural characterization of the compounds was achieved by UV-visible, IR and especially NMR spectroscopy. This study shows evidence of rotamers with NH bonds cis and trans with respect to the thiocarbonyl sulphur group. Also we report the activation free energies for hindered rotation around the CN bonds close to the coalescence temperature in TU, [Cr(CO) 5TU] (Cr(CO) 5DptTU], DtBTU, [Cr(CO) 5DtBTU] and [W(CO) 5DtBTU].