Thiocarbonyl Sulfur Research Articles

ChemInform Abstract: COPPER(I) COMPLEXES OF NEUTRAL, DEPROTONATED AND PROTONATED 4,6‐DIMETHYLPYRIMIDINE‐2(1H)‐THIONE

AbstractDer Titelligand wird durch die Umsetzung von Thioharnstoff mit Acetylaceton in Ethanol synthetisiert und bei pH 7‐8 als neutrale Verbindung oder durch Zugabe von Halogenwasserstoffsäuren als Hydrohalogenid isoliert.

ChemInform Abstract: PALLADIUM(II) AND PLATINUM(II) COMPLEXES OF RHODANINE AND 3‐METHYLRHODANINE

AbstractDie Pd‐ und Pt‐Komplexe (I)‐(VI) werden durch stöchiometrische Umsetzung von Pd(II)‐hydroxid oder ‐oxid bzw. Pt(II)‐dihalogenid mit den Titelliganden unter Zugabe von Halogenwasserstoffsäure bzw. Perchlorsäure in geeignetem Lösungsmittel (EtOH, EtOH/Aceton oder Aceton/Methylenchlorid) dargestellt.

ChemInform Abstract: COPPER(I)COMPLEXES OF RHODANINE

AbstractDer Hydroxo‐Cu‐Komplex (I) wurde durch Reaktion des Liganden in EtOH mit einer Suspension aus einer ethanolischen Ammoniaklösung und einer ethanolischen CuClz‐Lösung dargestellt.

Quantitative values of softness and structure of dimetallic tetrathiocyanate complexes

Bimetallic tetrathiocyanate complexes of the type MM′ (SCN) 4·xL [M = Ni(II), Co(II), Zn(II); M′ = Cd(II), Hg(II) and L = thiazolidinethione (tzt), thiohydantoin (thn), ethylenethiourea (etu); x = 2, 4, 6] have been prepared and their structures have been proposed by elemental analysis molar conductance, magnetic moment, infrared spectral, electronic spectral studies quantitative values of softness. These studies indicate that the complexes are of two types: cationic-anionic, viz. [ML x] ++[Cd(SCN) 4] − −[M = Co(II), Ni(II); L = tzt, thn, etu; x = 4, 6] and monomeric thiocyanate bridged viz.L 2M(NCS) 2Hg(SCN) 2 [M = Zn, Co, Ni; L = tzt, etu, thn] and L 4′Ni(NCS) 2Hg(SCN) 2 (L′ = etu, thn). Thiocarbonyl sulphur is the donor site in cationic-anionic complexes and imino nitrogen in bridged thiocyanate complexes in all three ligands. The relative strength of thiocyanate bridges have been correlated with the total softness difference ΔTE n‡ (MM′) which was calculated using Klopman's equation. Symmetry and group theoretical calculations have also been made to support the proposed structures.

Copper(I) complexes of neutral, deprotonated and protonated 4,6-dimethylpyrimidine-2 (1H)-thione

The following copper(I) complexes of 4,6-dimethylpyrimidine-2(1H)-thione (HL), its protonated cation (H2L+) and deprotonated anion (L−) have been prepared: CuL, Cu(HL)X (X = Cl, Br or I), Cu(HL)2X (X = C1 or Br), Cu2(HL)3Br2, Cu(H2L)X2 (X = Cl or Br), Cu3(HL)2LA2 (A = ClO4 or BF4 ). The i.r. spectra show that in all the HL and L− complexes and in the Cu(H2L)Br2 complex, the ligands are S, N coordinated to the metal ion, while in Cu(H2L)Cl2 only the thiocarbonylic sulphur is coordinated, probably bridging two copper(I) atoms. Thev(CuN) (288–317 cm−1 ) andv(CuS) (191–225 cm−1 ) have uniform frequency values in all the complexes. The halide ions are, in all their complexes, wholly or in part coordinated giving twov(CuX) bands which may indicate an asymmetrical Cu-X ⋯Cu halide bridging bond.

Palladium(II) and platinum(II) complexes of rhodanine and 3-methylrhodanine

The following palladium(II) and platinum(ll) complexes of rhodanine (HRd) and 3-methylrhodanine (MRd) have been prepared: Pd(HRd)1.5Cl2, Pd(HRd)2Br2, Pd(HRd)2Br2 · 0.25 EtOH, M(MRd)2X2 [M = Pd, X = Cl (0.25 EtOH) or Br; M = Pt, X = Cl or Br], Pd(MRd)3Br2, and M(MRd)4(ClO4)2 (M = Pd or Pt). The ligands are coordinated to the metal through the thiocarbonylic sulphur atom. Pd(HRd)1.5Cl2 has presumably a structure such as (X = Cl or Br) complexes have a trans-planar coordination. Pd(MRd)2X2 (X = Cl or Br) complexes arecis-planar coordinated. Pd(MRd)3Br2 has presumably a square coordination with two MRd molecules and two CI ionscis-coordinated in the equatorial plane, and a MRd molecule and a Cl ion weakly bonded in apical position. The M(MRd)4(ClO4)2 complexes have square planar coordination.

Copper(I) complexes of rhodanine

Some new crystalline copper(I) complexes of rhodanine (HL) have been prepared and studied by i.r. and conductometric methods. The neutral ligand is bonded to the metal atom through the thiocarbonylic sulphur atom. The Cu(HL)2OH · 0.5 H2O complex has a dimeric tetrahedral hydroxyl-bridged structure as have the isostructural halides Cu(HL)2X (X = Cl, Br and I) for which the halide-bridged stretching bands have been identified. The Cu(HL)3A (A = ClO4, BF4, 0.5 SO4 and CF3CO2) complexes have monomeric distorted tetrahedral structures with the anion bonded to the metal.

Nickel(II) and cobalt(II) complexes of rhodanine

Nickel(II) and cobalt(II) complexes of rhodanine (Hrd) were prepared from the metal chloride or acetate and the ligand. With an excess of NH3, the octahedral [Ni(NH3)6](Rd)2 and [Co(NH3)5Rd]Rd complexes are ob-tained; use of only two NH3 equivalents per metal ion yields the Ni(Rd)2 sd HRd · NH3 and [Co(Rd)2 ] · 1.5 H2O complexes, the first with tetragonally distorted hexacoordination and the second with polymeric octahedral coordination. By using two equivalents of NaOH per metal ion, the binuclear [Ni(Rd)2][Ni(Rd)2 · (HRd)2] · 2 H2O complex is formed having one diamagnetic planar and one high spin octahedral chromophore. Rhodanine is coordinated through the thiocarbonylic sulphur in the neutral form and through the thiocarbonylic sulphur and the deprotanated nitrogen atoms in the rhodanidato anionic form.

Steric Effects of Alkyl Substituents on the N–H Stretching Absorptions and Rotational Isomerism of N,N′-Dialkylthioureas

Abstract The fundamental N–H stretching absorptions of twenty nine N,N′-dialkylthioureas were observed in dilute solutions. The observed frequencies were classified into five groups assignable to the out, three different types of the trans, and the cis forms. The steric hindrance between the bulky t-butyl group and the thiocarbonyl sulfur, which is larger than for N,N′-dialkylureas, was suggested to cause the out form. Dialkylthioureas of RTUtB type seem to exist to a great extent in the trans-out conformation in solutions. It is suggested that it is not the N–H group with the bulky t-butyl group but the N–H group in the opposite part which is out of the skeletal plane. The energy difference between the out and the trans forms was found to be ΔH=430±100 cal mol−1.

13C n.m.r. spectra of some thiobenzamides. Correlation between 13C and 1H n.m.r. spectra and signal assignments of syn and anti CH2 groups

Abstract13C n.m.r. spectra of a series of N,N‐disubstituted thioamides have been recorded and signal assignments were performed. Separate signals are observed for methylene groups fixed on the nitrogen atom. Since the carbon atom syn to the thiocarbonyl sulfur resonates at higher field than the anti carbon, the syn‐anti assignment in 1H n.m.r. is easily obtained by selective double irradiation. This method, which is rapid and reliable, affords a rather general solution to the interesting problem of resonance assignments in tertiary amides and thioamides (and in analogous molecules such as oximes and nitrosamines).

Donor properties of thiohydantoin and pseudothiohydantoin towards cobalt(II) and nickel(II) salts

Coordination complexes of the type [CoL2] X2 (L = thiohydantoin (thn), pseudothiohydantoin (pthn); X = Cl, Br, I), [Ni(thn)4] Cl, and [Co(pthn)6] (ClO4), have been prepared and characterized by elementary analysis. The sites of bonding in ligands and configuration of the complexes have been determined with the help of physical properties, magnetic data, conductance data, i.r. and electronic spectral studies. The site of bonding in thn is thiocarbonyl sulphur and in pthn carbonyl oxygen. The cobalt halide complexes of thn and pthn are tetrahedral with C2v symmetry, [Ni(thn)4] Cl2 is octahedral with D4h symmetry and [Co(pthn)6] (ClO4), is octahedral with Oh cubic symmetry. All complexes except [Co(pthn)6] (ClO4)2, which is a 1 : 2 electrolyte, are non-conducting.

Spectres photoelectroniques d'heterocycles carbonyles et thiocarbonyles

Photoelectron spectra of carbonyl and thiocarbonyl derivatives of triazole and thiazole have been analysed. The influence of exocyclic groups on the nature and the energies of molecular orbitals has been evaluated. The data satisfactorily complete a previously established correlation between the nucleophilic reactivity of thiocarbonyl compounds and ionisation potential of an electron localized in a lone pair of the thiocarbonyl sulfur.

Metal complexes of sulphur-nitrogen chelating Agents. I. 2-aminocyclo-pentene-l-dithiocarboxylic acid complexes of Ni(II), Pd(II) and Pt(II).

The Ni(II), Pd(II) and Pt(II) chelates of 2-amino- cyclopentene-l-dithiocarboxylic acid (ACDA) are described. With each metal ions, two differently colored products having identical composition M(ACDA) 2 are obtained when reactions are carried out with the acid itself and its ammonium salt. PMR spectra of ACDA indicates strong hydrogen bonding between one amino proton and thiocarbonyl sulphur atom. The nature of bonding in the complexes have been investigated from their i.r, pmr and electronic spectra, magnetic moment, thermal analysis and X-ray diffraction data. In all the chelates bonding with metal ions occur through amino nitrogen and deprotonated thiolsulphur. The stability constant of Ni-ACDA complex has been evaluated spectrophotometrically. Ni(ACDA) 2 forms a 1:2 adduct with pyridine. The color difference in the chelates probably arises due to geometrical isomerism.

Infrared and raman spectra of (thioacetoxythio)triorgano derivatives of silicon, germanium, tin and lead

The IR and Raman spectra of (thioacetoxythio)trimethyl-Group IVb metals were recorded and an attempt was made to elucidate the structures by spectra. It is concluded that the bonding is similar to that of organic dithio acetates and that intramolecular coordination of the thiocarbonyl sulfur to Group IVB metals is small or negligible. Characteristic absorption bands of C(S)S groups are found near 880–860 cm −1.

Electronic structure of sulphur compounds VI. Photoelectron spectra of some simple thiocarbonyl compounds

The photoelectron spectra of a number of simple thiones including thiofenchone, thiocarbonates and thioamides have been recorded, and the bands corresponding to ionization energies in the range 7.5–13 eV have been interpreted using vibrational fine structure, comparison of He-I and He-II spectra, and CNDO/S calculations. In all compounds the non-bonded orbital mostly localized on the sulphur atom has the lowest ionization potential. The position of the bonding π and σ orbitals show a marked sensitivity to the nature of the substituents on the thiocarbonyl sulphur atom.

ChemInform Abstract: NICKEL(II) CHLORIDE COMPLEXES OF 1,5-DISUBSTITUTED 2,4-DITHIOBIURETS

The complex compounds formed by the interaction of Nickel(II) chloride with 1,5-disubstituted 2,4-dithiobiurets, have been isolated and characterised. The structure of these complexes have been studied by i.r. spectra, conductance and magnetic susceptibility measurements. It has been found that coordination occurs in these ligands through thiocarbonyl sulphur atoms, present in ligand molecule, which is supported by the potentiometric titrations of ligands and complexes with iodine in THF.

Spectroscopic and Coordination Behavior of α-Cyanothioacetamide

Abstract α-Cyanothioacetamide (CTAM) complexes of cuprous chloride CuCl–2CTAM and cuprous bromide CuBr–2CTAM have been prepared. The infrared spectra of CTAM and its complexes, and the laser Raman spectrum of CTAM have been recorded. Assignment of the frequencies of the ligand has been made on the basis of a normal coordinate analysis using the Urey-Bradley force field. The copper (I) complexes are inferred to have thiocarbonyl sulfur and amide nitrogen bonded CTAM as evidenced from infrared and electronic spectra.

Nickel(II) chloride complexes of 1,5‐disubstituted 2,4‐dithiobiurets

AbstractThe complex compounds formed by the interaction of Nickel(II) chloride with 1,5‐disubstituted 2,4‐dithiobiurets, have been isolated and characterised. The structure of these complexes have been studied by i.r. spectra, conductance and magnetic susceptibility measurements. It has been found that coordination occurs in these ligands through thiocarbonyl sulphur atoms, present in ligand molecule, which is supported by the potentiometric titrations of ligands and complexes with iodine in THF.

Studies of the Thiocarbonyl Compounds. III. The Mechanism of the Thermal Rearrangement of Aryl Thionocarboxylates

Abstract The thermal rearrangement of aryl thionocarboxylates was kinetically investigated in diphenyl ether. The rate constants of the rearrangement of aryl N,N-dimethylthionocarbamates were well correlated with the σ− values, but the plots of the electron-releasing para-substituents deviated slightly on the lower side of the meta correlation line. A good linear free-energy relationship existed between the rearrangement of aryl N,N-dimethylthionocarbamates and the bimolecular nucleophilic reaction of 4- or 5-substituted 1-chloro-2-nitrobenzenes with piperidine. By the use of the substituent constants obtained from the latter reaction for the electron-releasing para-substituent constants, a fairly good ρ–σ− relationship was obtained. Linear free-energy relationships also existed between the rearrangements of aryl N,N-dimethylthionocarbamates and aryl thionobenzoates, and between the rearrangements of aryl N,N-dimethylthionocarbamates and O-aryl S-phenyl dithiocarbonates. The order of the reaction constants was in accord with that of the inductive effects of the α-substituents of the thiocarbonyl group, so the electron-releasing conjugative effects of the α-substituents of the thiocarbonyl group did not play important roles in the rate-determining step. The present results indicate that the thermal rearrangement of aryl thionocarboxylates is an intramolecular SN–Ar which involves a four-membered cyclic transition state formed by a nucleophilic attack of the lone-pair electrons of the thiocarbonyl sulfur atom on the migrating aromatic ring.

Pseudotetrahedral Co II complexes with thio- and seleno-carbamate esters

Thiocarbamate esters L = RHNCSOR′ act as unidentate ligands through their S atoms towards Co II giving pseudotetrahedral CoL 2X 2 (X = Cl, Br, I) complexes. The complexing behaviour of L is therefore similar to that of substituted thioureas RHNCSNHR′, also in electronic spectral patterns and spectrochemical parameters values. However, the effect of -OR′ substituents compared to -NHR′ of thioureas reduces markedly the affinity of thiocarbonyl sulfur for Co II, and results in much more limited stability and easier solvolytic displacement of thiocarbamate complexes. Selenocarbamate complexes appear to be even less stable than the corresponding thiocarbamate complexes, but nevertheless CoL′X 2 (L′= N-phenyl-O-methylselenocarbamate, X = Br, I) could be prepared; their electronic spectra are consistent with lower spectrochemical position and stronger nephelauxetic effect of the Se donors. The crystal and molecular structure of one of these complexes, dibromo-bis(O-ethyl,N-phenylthiocarbamate)cobalt(II), Co[(C 6H 5)NHCS(OC 2H 5)] 2Br 2, has been determined from three-dimensional single-crystal X-ray data collected by standard film techniques. The structure has been refined by least-squares methods to a conventional R factor of 0.078 for 1330 non zero reflections. The neutral complex crystallises in space group C2/c of the monoclinic system with a cell of dimensions a = 25.95±0.02, b = 5.82±0.02, c= 15.22±0.02 Å, β = 104.3±1°; V = 2227 Å 3. ϱ(exp) is 1.72±0.04 g/cm 3 in good agreement with 1.73 g/cm 3 as calculated for Z = 4. The molecule is crystallographically required to possess a twofold symmetry axis with cobalt occupying the 4(e) special positions of the space group. The complex consists of a cobalt atom tetrahedrally coordinated by two bromine atoms and by sulphur atoms of the two thiocarbamate ligands. The CoBr and CoS distances are 2.394(2) and 2.238(3) Å respectively. A strong hydrogen bond interaction between the hydrogen belonging to nitrogen and the bromine has been revealed (HN ... Br = 3.36 Å). Several features of the geometry within the molecule are also given and discussed.