Chloro Gold Research Articles

Bi-functional natural polymers for highly efficient adsorption and reduction of gold

Designing and synthesizing cost-effective and biodegradable adsorbents for recovering gold from electronic acidic waste have immense sustainable development significance. Herein, three natural macromolecules (polydopamine, chitosan and cellulose) as raw materials were selected to be chemically crosslinked with tetrafluoroterephthalonitrile (TFN) through aromatic nucleophilic reaction, respectively. Then cyano groups of the cross-linked products were converted into amides under alkaline conditions then gained PDA-TFN-A, Chitosan-TFN-A and Cellulose-TFN-A for specifically binding gold. The gold adsorption capacities were 2771.8, 2680.0 and 1992.0 mg g−1 for PDA-TFN-A, Chitosan-TFN-A and Cellulose-TFN-A, respectively. Moreover, various physicochemical and spectroscopic studies provided insight into the binding process, confirming the highly efficient adsorption and in-situ reduction of gold of bifunctional natural polymers based on the interaction of amide functional groups with Au and chloro gold complexes. In addition, the comparative analysis proved the optimum behavior of bi-functional natural polymer PDA-TFN-A with high capacity, selectivity, stability, and fast adsorption kinetics (15 min) for adsorption of gold. This work delineated a promising strategy for the application of eco-friendly natural polymers to solve environmental problems.

Spectroscopic Evidence for Ligand Substitution Reactions at the Solid-Liquid Interface of a Sub-micrometer Gold(I) Carbene Complex.

Colloidal coordination compounds in the sub-micrometer range were synthesized from a chloro gold(I) carbene complex via the anti-solvent procedure and stabilized by a surfactant shell of Tween 20. This compound was successfully applied as model system to monitor heterogeneous multiphase ligand substitution reactions at the solid-liquid interface.

Spectroscopic Evidence for Ligand Substitution Reactions at the Solid–Liquid Interface of a Sub‐micrometer Gold(I) Carbene Complex

AbstractColloidal coordination compounds in the sub‐micrometer range were synthesized from a chloro gold(I) carbene complex via the anti‐solvent procedure and stabilized by a surfactant shell of Tween 20. This compound was successfully applied as model system to monitor heterogeneous multiphase ligand substitution reactions at the solid–liquid interface.

Au (III) uptake by triazine polyamine polymers: Mechanism, kinetic and equilibrium studies

Triazine-polyamine polymers were successfully synthesized and adsorption of the gold (III) ions from chloride-containing solutions was carried out by comparing the effect of amine chain lengths in the polymers triazine-ethylenediamine (EDA), triazine-triethylenetetramine (TETA) and triazine-pentaethylene hexamine (PEHA). The second-order kinetic equation provides the best correlation for the adsorption process. Langmuir equation has a good fit for all the adsorption systems. Langmuir monolayer adsorption capacities of the EDA, TETA and PEHA polymers were 548, 1003 and 1086mg/g, respectively. Adsorption mechanism was determined using FTIR, XPS, SEM, SEM Mapping and EDS. Adsorption mechanism is followed by ionic and surface complex formation mechanisms. Hydroxy chloro gold complexes were more interacted with nitrogen atoms of amine groups in polymers than nitrogen atoms in triazine rings. The adsorption capacity did not decrease after using all polymers five times. Furthermore, elution of the adsorbed Au (III) ions was made easily using 3% (m/v) thiourea solution in 1M HCl. From the results, it was concluded that EDA, TETA and PEHA polymers have a high gold uptake capacity and are highly efficient for the recycling of gold.

Mono N,C,N-pincer complexes of titanium, vanadium and niobium. Synthesis, structure and catalytic activity in olefin polymerisation

Transmetallation of 4,4'-bis{(2,6-bis[(dimethylamino)methyl]phenylgold)diphenyl-phosphino}biphenyl (3) with MCl(4) (M = Ti, NbCl, V) in benzene gave the corresponding transition metal pincer complexes (4) and insoluble 4,4'-bis[P-(chloro gold(I))diphenylphosphino]biphenyl (2), which can be quantitatively recovered and recycled. Interestingly, 3 did not react with TiCl(3). However, reaction of 2,6-bis[(dimethylamino)methyl]phenyllithium (1) with TiCl(3) resulted in formation of the novel diaryltitanium(IV) compound 5 (16% yield), comprising one N,C,N-mer bound NCN-pincer ligand and a second NCN-pincer ligand that is rearranged from a 1,2,6-isomer to a 1,2,4 one. The latter NCN-ligand is dianionic and is bidentate bonded; one of the CH(2)NMe(2) substituents (para to C'(ipso)) is non-coordinated, while the second CH(2)NMe(2) group, after C-H activation of one of the Me groups, is η(2)-C,N-bonded to the titanium centre trans to C(ipso) of the mer-NCN ligand. The new NCN-pincer metal complexes 2,6-bis[(dimethylamino)methyl]phenylTiCl(3) (4a) and 2,6-bis[(dimethylamino)methyl]-phenylVCl(2) (4d) gave, after immobilization on MgCl(2)-based supports, very high activity in ethene polymerisation.

Azo Isocyanide Gold(I) Liquid Crystals, Highly Birefringent and Photosensitive in the Mesophase

Isocyanide ligands bearing an azo group and one alkoxy chain OC(n)H(2n+1) have been synthesized. They are calamitic liquid crystals for n > 4 and display nematic (n = 8, 12) and SmA (n = 12) mesophases. Their gold(I) compounds [AuX(CNR)] (X = Cl, C(6)F(5); R = C(6)H(4)N horizontal lineNC(6)H(4)OC(n)H(2n+1), n = 4, 8, 12) have been obtained by displacement of a weakly coordinated ligand. The chloro gold(I) compounds exhibit nematic (n = 4) and SmA mesophases, and decompose at temperatures higher than 200 degrees C, before reaching the clearing point. The pentafluorophenyl gold(I) compounds show nematic and SmA (n = 12) mesophases. All the derivatives are photosensitive in solution because of trans to cis isomerization of the azo group under UV light, which reverts photochemically or thermally to the trans isomer. Irradiation in the mesophase also induces isomerization with consequent destabilization of the mesophase to an isotropic liquid; the mesophase is recovered as soon as illumination stops. These azo mesogens show high birefringence values, higher for the linear gold complexes than for the free azo ligand.

Comparative studies on the cytotoxicity, cellular and nuclear uptake of a series of chloro gold(I) phosphine complexes

Gold(I) phosphine complexes have shown promising results as a novel class of anticancer drugs in a variety of biochemical and pharmacological investigations. Studies on pharmacokinetic properties of these species are rare. Here we report the results of a comparative study on the cytotoxicity, cellular and nuclear uptake of a series of chloro gold(I) phosphine complexes (Cl–Au–P(R) 3, R = Me, Et, tert-But, Ph) containing different ligands on the phosphor. Cellular and nuclear gold levels in HT-29 colon carcinoma and MCF-7 breast cancer cells were measured by electrothermal atomic absorption spectrometry. All studied complexes exhibited significant antiproliferative effects in both investigated cell lines. Cellular and nuclear gold levels were enhanced especially for Cl–Au–P(Ph) 3 indicating a positive influence of larger and more lipophilic substituents.

ジブチルカルビトールによる金クロロ錯体の選択的抽出および選択的還元

ジブチルカルビトールによる金クロロ錯体の選択的抽出および選択的還元

Dithiophosphinates of gold (I); oxidative addition of Cl2to a neutral, dinuclear gold(I) dithiophosphinate complex, and X-ray crystal structures of [AuS2P(C2H5)2]2, [AuS2PPh2]2, Au2(CH2)2PMe2(S2PPh2), and Au2Cl2[(CH2)2PMe2][S2PPh2

The formation and characterization of dinuclear gold(I) dialkyl- and diaryl-dithiophosphinate complexes of the type [AuS2PR2]2are described. The complexes are readily prepared from the reaction between a chloro–gold(I) starting material and the corresponding dithiophosphinate salt. The structures of the complexes show both the absence (R = Et, 1) and presence (R = Ph, 2a) of intermolecular Au···Au interactions as confirmed by X-ray crystallographic study in the solid state. Reaction between [AuS2PPh2]2and [Au(CH2)2PMe2]2in CH2Cl2solution leads to a ligand transfer reaction to form the hetero-bridged complex [Au2{(CH2)2PMe2S2PPh2}] (3a) in high yield. Additionally, the latter complex reacts with Cl2to form the oxidative addition product [Au2Cl2{(CH2)2PMe2S2PPh2}] (4), the first gold(II) complex with a S-P-S bridging moiety. The X-ray crystal structure of both 3a and 4 exhibit rare boat conformations in the solid state, and 4 has a formal Au(II)—Au(II) single bond of 2.5611(5) Å. Reaction between [AuS2PPh2]2and dppm (dppm = Ph2PCH2PPh2) leads to a sparsely soluble three-coordinate dinuclear gold(I) complex with the molecular formula [Au2{dppmS2PR2}2]n(n = 1 or [Formula: see text]) (5).Key words: dithiophosphinates, ylide, dithiols, gold-gold bond.