Thiocyanate Derivatives Research Articles

Octahedral alkylidyne complexes of tungsten with chelating ligands as precursors for polynuclear compounds. Crystal structures of [W(CR)(CO)2(dmpe)(NCS)] and [Co2W(µ3-CR)(CO)8(dmpe)Br](R = C6H4Me-4, dmpe = Me2PCH2CH2PMe2)

The tungsten carbyne complexes [W(CR)(CO)2(L–L)X](R = C6H4Me-4) where L–L = 2,2′-bipyridine (bipy), 1,2-bis(dimethylphosphino)ethane (dmpe), or 1,2-bis(diphenylphosphino)-benzene (dppb), and X = Cl, Br, or NCS have been prepared and the structure of the N-bonded thiocyanate derivative [W(CR)(CO)2(dmpe)(NCS)] determined by X-ray diffraction. The reaction of the octahedral carbynes with [AuCl(tht)](tht = tetrahydrothiophene) gave the dimetallic species [AuW(µ-CR)(CO)2(L–L)X(Cl)], which when X ≠ Cl are mixtures due to an interchange of X and Cl between the Au and W. The carbynes also reacted with [Au(C6F5)(tht)] to give [AuW(µ-CR)(CO)2(L–L)(C6F5)X], which for X = NCS are mixtures of two isomeric forms. The carbynes containing dmpe reacted with [Co2(CO)8] to give the trimetallic clusters [Co2W(µ3-CR)(CO)8(dmpe)X](X = Cl or Br) which in solution exist as a mixture of interconverting isomers. The X-ray crystal structure determination of the bromo derivative revealed that, in the solid, the stereochemistry of the W(CO)2(dmpe)X fragment is different from that corresponding to the starting carbyne. The dmpe carbynes also reacted with [Fe2(CO)9] in toluene to afford the bimetallic compounds [FeW(µ-CR)(CO)6(dmpe)X](X = Cl or Br) having a Fe(CO)4 fragment co-ordinated to the WCR bond.

Complexes of Cobalt(II), Nickel(II) and Zinc(II) Azides and Thiocyanates with Mepirizole, an Anti-Inflammatory Agent

Abstract The synthesis and characterization of thiocyanate and azide derivatives of metal complexes of mepirizole [4-methoxy-2-(5-methoxy-3-rnethyl-pyrazol-1-yl)-6-methylpyrimidine, hereinafter L] with cobalt(II), nickel(II) and zinc(II) is reported. Spectroscopic and magnetic results for ML2(NCS)2 (M α Co, Ni) biscomplexes indicate isolated MN6 chromophores and a m-octahedral arrangement around the M(II) ion. Also for the ML (N3)2 (M α Co, Ni) compounds, an essentially octahedral environment is inferred from the spectroscopic data, thus requiring polymerization through azido bridges. Finally, for both zinc derivatives a distorted tetrahedral environment around the metal atom is suggested.

Synthesis of isothiocyanate compounds in the presence of polymer-supported ions

Halide derivatives may be converted directly into their isothiocyanate homologues by the action of thicyanate ions fixed to the macromolecular network of an ion exchange resin. The reaction leads first to the thiocyanate derivative (kinetic product), which is isomerized to the isothiocyanate derivative (thermodynamic product). The isomerisation process depends on both the structure of the halogenated substrate and the nature of the reaction environment. This isomerisation is catalysed by polymer-supported reagents but is inhibited by a protic solvent such as butanol. These results suggest that the ionization and preliminary dissociation of the thiocyanate isomer are followed by an attack on the carbonium ion by the nitrogen atom of the thiocyanate ion.

Chelated compounds and derivative of β-alkoxycarbonylalkyltin chlorides — 5-arylazo-8-quinolinolates, alizarinates, and thiocyanate: preparation and spectroscopic studies

Complex formation with chelating ligands like 5-phenylazo-8-quinolinol, 5-(2I-carboxyphenylazo)-8-quinolinol, 1,2-dihydroxyanthraquinone (i.e., alizarin), and 1-nitroso-2-naphthol is due to nucleophilic attack on tin of the β-alkoxycarbonylalkyltin chlorides (a unique class of PVC stabilizer intermediates) with the subsequent elimination of hydrogen chloride. A number of complexes of the types R2SnL2, RSnL2Cl, R2SnLCl, R2Sn(LIHI)2, R2SnLII, and RSnLIICl (where R = CH3OCOCH2CH2—, C4H9OCOCH2CH2—, and CH3OCOCH(CH3)CH2—; LH = 5-phenylazo-8-quinolinol, 1-nitroso-2-naphthol; LIHHI = 5-(21-carboxyphenylazo)-8-quinolinol; and LIIH2 = 1,2-dihydroxyanthraquinone) and a thiocyanate derivative viz. (CH3OCOCH2CH2)2Sn(SCN)2 have been prepared. 5-Arylazo-8-quinolinols exhibit azo–hydrazone tautomeric equilibria but their complexes exist only in the azo form. β-Alkoxycarbonylethyltin alizarinates are somewhat different from other complexes. In these complexes two hydroxyl groups of alizarin have been utilised in complex formation, moreover, one of the two carbonyl groups of alizarin also remains involved in coordination to tin. In (CH3OCOCH2CH2)2Sn(SCN)2, the thiocyanate group is possibly linked to tin atom through nitrogen. All the complexes and the thiocyanate derivative have been characterised by elemental analyses, electronic, ir, and 1H nmr spectra. Possible structural features of the compounds are discussed.

The effect of dodecyl sulfate on immunoglobulin hapten binding

The instantaneous effect of dodecyl sulfate (DDS), in the m M concn range, on the binding of monovalent hapten by immunoglobulin was examined. Fluorescence measurements were utilized to study the effect of the detergent on sheep antiserum generated against thyroxin (T4) and against methamphetamine. Haptens were conjugated with the thiocyanate derivative of fluorescein in order to determine hapten binding on the basis of increased fluorescence polarization for the fluorescein-thiocarbamyl-hapten adducts (FT4 or FA) bound to immunoglobulin. Incubation of anti-T4-serum with DDS for 1 hr before the addition of FT4 resulted in diminished binding. The effect occurred at DDS concns greater than 0.1 m M and was essentially complete at a DDS conc of 1 m M. A kinetic study demonstrated a two stage process. An initial, rapid stage, with a half time less than 30 sec accounted for a reduction of immunoglobulin binding by 75%. The remaining 25% binding capacity was lost during a second, much slower phase with a half-time of about 1 1 2 hr. Prior hapten binding inhibited the effect of DDS. The degree of protection from combining site denaturation afforded by prior hapten binding was limited by the dissociation rate of bound hapten. The major, rapid phase was completely and immediately reversible by dilution. Prolonged incubation in DDS resulted in irreversible denaturation. The overall rate of DDS denaturation of the entire immunoglobulin molecule, as revealed by changes in the circular dichroism spectrum of a sheep gamma globulin fraction, was considerably slower than the denaturation rate of the combining site.

Iso- Thiocyanate Derivatives of Diarylthallium(III) Cation and their Microbiocidal Propensities

Iso- Thiocyanate Derivatives of Diarylthallium(III) Cation and their Microbiocidal Propensities

Lactoperoxidase, peroxide, thiocyanate antimicrobial system: correlation of sulfhydryl oxidation with antimicrobial action

The antimicrobial activity of the lactoperoxidase, peroxide, thiocyanate system against Escherichia coli was directly related to the oxidation of bacterial sulfhydryls. Lactoperoxidase catalyzed the oxidation of thiocyanate, which resulted in the accumulation of hypothiocyanite ion, OSCN-. A portion of the bacterial sulfhydryls were oxidized by OSCN- to yield sulfenic acid and sulfenyl thiocyanate derivatives. The remaining sulfhydryls were not oxidized, although OSCN- was present in large excess. The oxidation of sulfhydryls to sulfenyl derivatives inhibited bacterial respiration. This inhibition could be reversed by adding sulfhydryl compounds to reduce the sulfenyl derivatives and the excess OSCN-. Also, this inhibition could be reversed by washing the cells so as to remove the excess unreacted OSCN-. After washing, the bacteria underwent a time-dependent recovery of their sulfhydryl content. This recovery resulted in recovery of the ability to respire. The inhibited cells were viable if diluted and plated shortly after the incubation with the lactoperoxidase, peroxide, thiocyanate system. On the other hand, long-term incubation in the presence of the excess OSCN- resulted in loss of viability. Also, the inhibition of respiration became irreversible. During this long-term incubation, the excess OSCN- was consumed and the sulfenyl derivatives disappeared.

Reaction of iron(III) salts with 2-pyridylamines. Synthesis and Physical data, Including mössbauer spectra

Complexes of iron(III) and iron(II) with various pyridylamines are reported (specifically di- and tri-(2-pyridyl)amine and 4- and 5- methyl-2-pyridyldi-(2-pyridyl)amine). The iron(III) complexes constitute three types which can be seen as stages in the base hydrolysis of the metal ion. Class A contains the anion [Cl 3 Fe·O·FeCl 3 ] 2− ; class B, which occurs only for the terdentate ligands, are monomers of the type [(ligand)FeX 3 ] (X= halogen). Most complex is class C, restricted to di-(2-pyridyl)amine, which are molecularly complex with two distinct iron sites, both spin 5 2 antiferromagnetically coupled. An aged specimen of one compound (4 years) shows considerable change in iron(III) environments and unusual temperature dependence of Mössbauer parameters. Iron(II) thiocyanate derivatives are reported. They are generally straightforward and most are ionic containing either four co-ordinate [Fe(NCS) 4 ] 2− or six co-ordinate [Fe(bidentate)(NCS) 4 ] 2− anions. The compounds reported are characterised as far as possible by reference to their magnetic properties and spectroscopic, particularly 57 Fe Mössbauer, data.

The reduction by dithionite of Fe(III) myoglobin derivatives with different ligands attached to the iron atom. A study by rapid-wavelength-scanning stopped-flow spectrophotometry.

1. The reductions of a number of sperm whale Fe(III) myoglobin-ligand complexes by sodium dithionite in a phosphate buffer pH 6.4, were investigated by using rapid-wavelength-scanning stopped-flow spectrophotometry. The ligands were azide, cyanide, fluoride, imidazole, thiocyanate and water. 2. The reduction of Fe(III) myoglobin cyanide led to the transient formation of Fe(II) myoglobin cyanide but no intermediate species were observable during the reductions of the other derivatives. The final product of the reaction in all cases was unliganded Fe(II)myoglobin. 3. Invesigation of the effect of dithionite concentration on the rate of reduction indicated that the SO2- radical ion was the active species in reducing the azide, cyanide, fluoride and thiocyanate derivatives. 4. Comparison of the observed rates of reduction at different ligand concentrations with those predicted for a pathway of reduction involving prior dissociation of the ligand, allowed us to estimate the rate of reduction with the ligand in position (outer-sphere reduction). There was a large variation in the relative rates of outer-sphere reduction in the order imidazole greater than CN- greater than SCN- greater than N3- greater than F-. The fluoride derivative was so resistant to outer-sphere reduction that the reaction with SO2- proceeded only by a pathway involving dissociation of F- before reduction. It was calculated that any direct reduction of this complex was at least 100 times slower than that of the azide derivative. 5. The results are discussed in terms of the possible rôle of the axial ligands in haem proteins and it is suggested that the pathway of the electron to the Fe(III) centre may be via the ppi orbitals of these ligands.

Bidentate group VB chelates. Part XV. Four- and five-coordinate cobalt(II) complexes of very soft donors. Planar coordination

Complexes have been isolated from reactions between cobalt(II) salts and the bidentate chelates o-C 6H 4(PPh 2) 2 (pp), o-C 6H 4(PPh 2)(AsPh 2) (ap), o-C 6H 4(AsPh 2) 2 (aa), cis-Ph 2AsCHCHAsPh 2 (vaa) and Ph 2AsCH 2CH 2AsPh 2 (dae). The ligand pp forms pentacoordinate [Co(pp) 2X] + (X = Cl, Br, l), and [CoL 2][CoX 4] which contain planar cations and tetrahedral anions in the solid state. In solution the latter partially isomerise into tetrahedral Co(pp)X 2 moieties. Similar [CoL 2][CoX 4] complexes were obtained with ap. The thiocyanate derivatives are formulated CoL (NCS) 2 (L = pp, ap, aa) and exhibit μ eff ∼ 2.5–2.9 B.M., suggesting they are rare examples of planar cobalt(II) with coordinated anions. Pentacoordinate [CoL 2(NCS)] + complexes were isolated for L = pp, vaa, and dae. Only pp afforded a diperchlorate, [Co(pp) 2] (ClO 4) 2. The aryldiarsine chelates dae and vaa produced planar Co(vaa)l 2, and tetrahedral Co(dae)l 2 and Co 2(dae) 3l 4.

Bidentate group VB chelates, Part VII. Some palladium(II) complexes with diphosphine, phosphine-arsine, and diarsine ligands, including some thiocyanate derivatives

Eighteen complexes of palladium(II) salts and the bidentate chelating ligands cis-1,2-bis(diphenylphosphino)ethylene (vpp). cis-1,2-bis(diphenylarsino)ethylene (vaa), cis-1-diphenylarsino-2-diphenylphosphinoethylene (vasp), and 9,10-bis(diphenylphosphino)phenanthrene (dpph) have been prepared and studied by infrared and electronic spectroscopic techniques. The thiocyanate complexes are formulated Pd(vpp)(SCN) 2 Pd(vaa)(SCN) 2 Pd(vasp)(SCN) 2 and Pd(dpph)(NCS)(SCN), and the possible factors promoting the different types of coordination are discussed.

The inactivation of papain and glyceraldehyde-3-phosphate dehydrogenase by phenyldiimide

Phenylhydrazine does not inactivate papain or glyceraldehyde-3-phosphate dehydrogenase under anaerobic conditions. The inactivation of papain and glyceralde-hyde-3-phosphate dehydrogenase under aerobic conditions is ascribed to the oxidation of phenylhydrazine by O 2 which generates phenyldiimide and H 2O 2, both of which react with the essential sulfhydryl groups and inactivate the enzymes. Phenyldiimide generated from methyl phenylazoformate inactivates both of the sulfhydryl enzymes under anaerobic conditions. The inactivation of papain and GPD with aerobic, aqueous solutions of [ 14C]phenylhydrazine introduces a small amount of radioactivity into the enzymes which is discharged by dithiothreitol. The amount of radioactivity bound to papain is increased when cyanide is present in the inactivation mixture.When the β-[ 14C]thiocyanoalanine derivative of papain is treated with phenylhydrazine the radioactivity is discharged from the enzyme. Cyanide evidently reacts with the sulfenic acid derivative of papain to form a thiocyanate derivative. Phenylhydrazine presumably displaces cyanide from the thiocyanate derivative to form a sulfenyl hydrazide derivative to account for the increased incorporation of [ 14C]phenylhydrazine when papain is inactivated with aerobic solutions of [ 14C]-phenylhydrazine in the presence of cyanide. When the sulfhydryl group of papain is oxidized to a sulfenic acid with H 2O 2 and then treated with [ 14C]phenylhydrazine, 14C is not incorporated into the enzyme. These experiments suggest that the H 2O 2 in the aerobic solutions of phenylhydrazine oxidizes the sulfhydryl group at the active site of papain to a sulfenic acid. The [ 14C]phenyldiimide in these solutions reacts to some extent with the active sulfhydryl group to form a sulfenyl hydrazide derivative.

Nickel(II) and copper(II) complexes of 2,4,4-trimethyl-1,5-diazapent-1-ene

Hexa-amminenickel(II) and tetra-amminecopper(II) perchlorates react with anhydrous acetone to yield β-aminoketimine perchlorate complexes analogous to cyclic quadridentate β-aminoketimine complexes recently described. A six-co-ordinate thiocyanate derivative of the nickel species is also described.

Some unusual complexes of iron with 1,10-phenanthroline and 2,2'-bipyridyl

The following hydroxy-bridged iron(III) complexes have been isolated for the first time : [phen2 Fe(OH)2Fe phen2](SO4)2,7H2O, [phen2 Fe(OH)2Fe phen2]Br4,2H2O, [bipy2 Fe(OH)2Fe bipy2](SO4)2,9H2O. Attempts to prepare thiocyanate derivatives of these complexes resulted unexpectedly in the synthesis of the compounds Fe(SCN)2 phen2,H2O and [FeSCN phen2]ClO4 which were investigated in the light of the well-known complexes of the type FeX2 chelate2. The compound [Fe phen3][Fe(CN)4 phen],5H2O which, except for water, has the same stoicheiometry as Fe(CN)4 phen2, is also described for the first time. The claim by Madeja (Chemicke Zvesti, 1965, 19, 186) that the compound Fe(SCN)2 bipy2 exists both as a red trans form (μeff 3.0 B.M.) and a violet cis form (μeff 5.2 B.M.) is not justified according to this work. It seems that the red form may be a mixture of the paramagnetic bis- and the diamagnetic tris-compounds.

Chemical blockade of the sympathetic nervous system in essential hypertension; experience with oral therapy with 688-A (N-phenoxy isopropyl-N-benzyl-beta-chloroethylamine hydrochloride).

THE EXACT nature of essential hypertension has not been clearly established, and, as a result, many drugs, diets, and operative procedures have been used in the treatment of this disease. In most instances therapy has either proved more annoying to the patient than the disease itself or produced variable results. The numerous theories regarding the etiological basis of essential hypertension have been summarized repeatedly by many authors,1but at present most observers agree that there are probably both neurogenic and humoral factors that produce and maintain blood pressure in certain persons at a hypertensive level. A great deal of the treatment has been aimed at controlling or eliminating the neurogenic factor, for the exact humoral mechanism that operates in hypertension has still not been clarified. Other drugs have been used because of their direct action upon the vascular system. Therapy with thiocyanate derivatives has been employed for years, and