Nickel Cyanide Research Articles

Two-dimensional nickel cyano-bridged coordination polymer thermally derived potent electrocatalysts for alkaline hydrogen evolution reaction

We present a versatile technique for fabricating potent Ni-based nanostructured inorganic electrodes (Ni-O, Ni-S, Ni-Se, Ni-P) using 2D nickel cyanide bridged CPs as a precursor. Ni-P has demonstrated the best HER catalysis and durability among them.

Synergistic Mechanistic Study of Nickel(0)/Lewis Acid Catalyzed Cyanoesterification: Effect of Lewis Acid

The highly selective nickel(0)-catalyzed cyanoesterification of cyanoformates with alkynes is greatly facilitated by Lewis acid (LA). We report density functional theory (DFT) investigations on the mechanistic details and provide a rational explanation of the “LA effect”. Our calculations disclose that an unusual biphosphine cycle including rate-determining oxidative addition of a C–CN bond, alkyne migratory insertion, and reductive elimination steps is more favorable than the generally accepted monophosphine cycle. The LA has a non-negligible impact on the mechanistic origin of selective C–CN bond activation. Furthermore, the presence of LA dramatically accelerates alkyne migratory insertion because the strong electron-withdrawing property of LA strengthens the coordination ability of the Ni center with alkyne to form the thermodynamically favorable five-coordinate nickel(II) cyanide carboxylate species, which then avoids the large deformation of the transition state of alkyne migration insertion to give...

Fe-Doped Ni3 C Nanodots in N-Doped Carbon Nanosheets for Efficient Hydrogen-Evolution and Oxygen-Evolution Electrocatalysis.

Uniform Ni3 C nanodots dispersed in ultrathin N-doped carbon nanosheets were successfully prepared by carburization of the two dimensional (2D) nickel cyanide coordination polymer precursors. The Ni3 C based nanosheets have lateral length of about 200 nm and thickness of 10 nm. When doped with Fe, the Ni3 C based nanosheets exhibited outstanding electrocatalytic properties for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For example, 2 at % Fe (atomic percent) doped Ni3 C nanosheets depict a low overpotential (292 mV) and a small Tafel slope (41.3 mV dec-1 ) for HER in KOH solution. An outstanding OER catalytic property is also achieved with a low overpotential of 275 mV and a small Tafel slope of 62 mV dec-1 in KOH solution. Such nanodot-incorporated 2D hybrid structures can serve as an efficient bifunctional electrocatalyst for overall water splitting.

Fe‐Doped Ni3C Nanodots in N‐Doped Carbon Nanosheets for Efficient Hydrogen‐Evolution and Oxygen‐Evolution Electrocatalysis

AbstractUniform Ni3C nanodots dispersed in ultrathin N‐doped carbon nanosheets were successfully prepared by carburization of the two dimensional (2D) nickel cyanide coordination polymer precursors. The Ni3C based nanosheets have lateral length of about 200 nm and thickness of 10 nm. When doped with Fe, the Ni3C based nanosheets exhibited outstanding electrocatalytic properties for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For example, 2 at % Fe (atomic percent) doped Ni3C nanosheets depict a low overpotential (292 mV) and a small Tafel slope (41.3 mV dec−1) for HER in KOH solution. An outstanding OER catalytic property is also achieved with a low overpotential of 275 mV and a small Tafel slope of 62 mV dec−1 in KOH solution. Such nanodot‐incorporated 2D hybrid structures can serve as an efficient bifunctional electrocatalyst for overall water splitting.

Detoxification of Heap after Gold Leaching Using Biodegradation

Bacteria which are adapted both to high content of toxic compounds and to the environments grow in autochthonous communities of gold heap leach (HL) wastes. In the following study of HL waste from a deposit in the Sakha (Yakutia) Republic (Russia) it was shown that microbial processes had a greater impact on the degradation of cyanides and of complex copper and nickel cyanides, respectively, compared to a chemical degradation. The diversity of bacterial communities growing under natural and model conditions was determined.

The extraction of platinum and palladium from a synthetic cyanide heap leach solution with strong base anion exchange resins

The use of ion exchange resins for the extraction of platinum and palladium from a synthetic cyanide leach solution is described in this paper. An increase in the concentrations of both platinum and palladium cyanide in solution from 0.15 to 0.45mg/L and from 0.40 to 1.2mg/L respectively resulted in higher equilibrium loadings while the first order constants remained constant. The solution pH did not have a significant effect on the equilibrium loading of platinum cyanide and palladium cyanide in the ranges 9 to 11. However, improvements in the loading kinetics of both these complexes were noticed with an increase in solution temperature from 30 to 60°C. Changes in zinc cyanide and nickel cyanide concentrations in the range 5 to 20mg/L did not have a significant effect on the adsorption of platinum cyanide and palladium cyanide. It was concluded that strong base anion exchange resins could effectively recover platinum and palladium cyanides from dilute synthetic cyanide solutions and that the exchange capacity and functionality of these ion exchange resins might have played an important role in their affinity for different metal anions in solutions.

Recovery of copper and cyanide from waste cyanide solutions using emulsion liquid membrane with LIX 7950 as the carrier

ABSTRACTThe feasibility of using emulsion liquid membranes (ELMs) with the guanidine extractant LIX 7950 as the mobile carrier for detoxifying copper-containing waste cyanide solutions has been determined. Relatively stable ELMs can be maintained under suitable stirring speed during mixing ELMs and the external solution. Effective extraction of copper cyanides by ELMs only occurs at pH below 11. High copper concentration in the external phase and high volume ratio of the external phase to ELMs result in high transport rates of copper and cyanide. High molar ratio of cyanide to copper tends to suppress copper extraction. The presence of thiocyanate ion significantly depresses the transport of copper and cyanide through the membrane while the thiosulfate ion produces less impact on copper removal by ELMs. Zinc and nickel cyanides can also be effectively extracted by ELMs. More than 90% copper and cyanide can be effectively removed from alkaline cyanide solutions by ELMs under suitable experimental conditions, indicating the effectiveness of using the designed ELM for recovering copper and cyanide from waste cyanide solutions

Competing hydrostatic compression mechanisms in nickel cyanide

We use variable-pressure neutron and X-ray diffraction measurements to determine the uniaxial and bulk compressibilities of nickel(II) cyanide, Ni(CN)2. Whereas other layered molecular framework materials are known to exhibit negative area compressibility, we find that Ni(CN)2 does not. We attribute this difference to the existence of low-energy in-plane tilt modes that provide a pressure-activated mechanism for layer contraction. The experimental bulk modulus we measure is about four times lower than that reported elsewhere on the basis of density functional theory methods [Phys. Rev. B 83 (2011) 024301].

Oxidation of carbon monoxide in basic solution catalyzed by nickel cyano carbonyls under ambient conditions and the prototype of a CO-powered alkaline fuel cell.

CO reduces nickel(2+) cyanides in basic solution to form tetrahedral Ni(0)(CN)(CO)3(-) or Ni(0)(CN)2(CO)2(2-). Both nickel(0) complexes can be oxidized back to nickel(2+) cyanide/hydroxide so that they behave as CO oxidation catalysts in basic solution. A primitive fuel cell was constructed to demonstrate the feasibility of a CO-powered fuel cell.

Chemistry and structure by design: ordered CuNi(CN)4 sheets with copper(ii) in a square-planar environment.

Layered copper-nickel cyanide, CuNi(CN)4, a 2-D negative thermal expansion material, is one of a series of copper(ii)-containing cyanides derived from Ni(CN)2. In CuNi(CN)4, unlike in Ni(CN)2, the cyanide groups are ordered generating square-planar Ni(CN)4 and Cu(NC)4 units. The adoption of square-planar geometry by Cu(ii) in an extended solid is very unusual.

Use of nickel(II) acetylacetonate and dimethylgold(III) acetylacetonate in gold on nickel plating

This study investigates the use of non-toxic materials in nickel and gold plating baths that are used to plate gold on nickel plated stainless steel surfaces. The physical and mechanical stability and adhesion of the plating obtained using such compositions are investigated. The thickness, colour and adhesion of the plating have been studied using X-ray measurements, visible spectrometry and hydrogen embrittlement tests respectively. The plating baths employed in this study, which contained nickel(II) acetylacetonate and dimethylgold(III) acetylacetonate, were found to be good alternatives to conventional nickel and gold plating baths because they contain toxic nickel sulphate and cyanide salts.

Screening Hofmann Compounds as CO2 Sorbents: Nontraditional Synthetic Route to Over 40 Different Pore-Functionalized and Flexible Pillared Cyanonickelates

A simple reaction scheme based on the heterogeneous intercalation of pillaring ligands (HIPLs) provides a convenient method for systematically tuning pore size, pore functionality, and network flexibility in an extended series of pillared cyanonickelates (PICNICs), commonly referred to as Hofmann compounds. The versatility of the approach is demonstrated through the preparation of over 40 different PICNICs containing pillar ligands ranging from ∼4 to ∼15 Å in length and modified with a wide range of functional groups, including fluoro, aldehyde, alkylamine, alkyl, aryl, trifluoromethyl, ester, nitro, ether, and nonmetalated 4,4'-bipyrimidine. The HIPL method involves reaction of a suspension of preformed polymeric sheets of powdered anhydrous nickel cyanide with an appropriate pillar ligand in refluxing organic solvent, resulting in the conversion of the planar [Ni2(CN)4]n networks into polycrystalline three-dimensional porous frameworks containing the organic pillar ligand. Preliminary investigations indicate that the HIPL reaction is also amenable to forming Co(L)Ni(CN)4, Fe(L)Ni(CN)4, and Fe(L)Pd(CN)4 networks. The materials show variable adsorption behavior for CO2 depending on the pillar length and pillar functionalization. Several compounds show structurally flexible behavior during the adsorption and desorption of CO2. Interestingly, the newly discovered flexible compounds include two flexible Fe(L)Ni(CN)4 derivatives that are structurally related to previously reported porous spin-crossover compounds. The preparations of 20 pillar ligands based on ring-functionalized 4,4'-dipyridyls, 1,4-bis(4-pyridyl)benzenes, and N-(4-pyridyl)isonicotinamides are also described.

ChemInform Abstract: Mono- and Dicarboxylation of α-Haloalkynes Catalyzed by Nickel Cyanide Under Phase-Transfer Conditions.

ChemInform Abstract: Mono- and Dicarboxylation of α-Haloalkynes Catalyzed by Nickel Cyanide Under Phase-Transfer Conditions.

ChemInform Abstract: Direct, Regioselective Hydrocarboxylation of Alkynes to Saturated Acids by Cobalt and Nickel Catalysts Under Phase-Transfer Conditions.

Abstract Phase transfer catalyzed carbonylation of alkynes in the presence of cobalt chloride, potassium cyanide, and nickel cyanide affords saturated carboxylic acids, with good selectivity observed for the branched-chain isomer.

Hysteresis in the Physisorption of CO2 and N2 in a Flexible Pillared Layer Nickel Cyanide

Rare hysteretic adsorption/desorption isotherms are reported for CO2 and N2 on a pillared Ni(1,2-bis(4-pyridyl)ethylene)[Ni(CN)4] compound (NiBpeneNiCN). The hysteresis occurs under moderate pressure and at temperatures above the critical temperatures of the respective gases. Powder X-ray diffraction measurements indicate that the material is an extended three-dimensional analogue of the well-known Hofmann clathrates which is formed through axial bridging of the in-plane octahedral Ni sites by the bidentate 1,2-bis(4-pyridyl)ethylene. The hysteretic behavior toward guest adsorption and desorption is attributed to a structural phase transition in the material resulting from a variation in the tilt angle of the 1,2-bis(4-pyridyl)ethylene pillars. Kinetics studies on the desorption of acetone from the material show two first-order processes with two rate constants yielding activation energies of 68 and 55 kJ/mol when loadings are greater than 1 equiv of acetone per formula unit. The CO2 adsorption/desorption isotherms on the series of structurally similar Ni(L)[Ni(CN)4] compounds, where L = pyrazine, 4,4'-bipyridine, 1,2-bis(4-pyridyl)ethane, and dipyridylacetylene, are also reported. In contrast to NiBpeneNiCN, the rigid members of this series show normal type I isotherms with no measureable hysteresis and no significant structural changes during the adsorption/desorption cycle, while the flexible 1,2-bis(4-pyridyl)ethane-bridged sample collapses in the guest-free state and shows no significant adsorption of CO2.

Surprises from a Simple Material—The Structure and Properties of Nickel Cyanide

The cyanide switch. The bonding of the cyanide ligand of Ni(CN)2⋅n H2O changes dramatically on dehydration to Ni(CN)2, equalizing the NiC and NiN bonds and switching the Ni2+ ion bound to nitrogen from high spin to low spin. Total neutron diffraction studies on Ni(CN)2 provide for the first time accurate structural data on this simple layered metal cyanide. Ni(CN)2 is a model two-dimensional negative thermal-expansion material. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z701246_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Surprises from a Simple Material—The Structure and Properties of Nickel Cyanide

Surprises from a Simple Material—The Structure and Properties of Nickel Cyanide

Interaction of Potassium Cyanide with the [Ni-4Fe-5S] Active Site Cluster of CO Dehydrogenase from Carboxydothermus hydrogenoformans

The Ni-Fe carbon monoxide (CO) dehydrogenase II (CODHII(Ch)) from the anaerobic CO-utilizing hydrogenogenic bacterium Carboxydothermus hydrogenoformans catalyzes the oxidation of CO, presumably at the Ni-(micro(2)S)-Fe1 subsite of the [Ni-4S-5S] cluster in the active site. The CO oxidation mechanism proposed on the basis of several CODHII(Ch) crystal structures involved the apical binding of CO at the nickel ion and the activation of water at the Fe1 ion of the cluster. To understand how CO interacts with the active site, we have studied the reactivity of the cluster with potassium cyanide and analyzed the resulting type of nickel coordination by x-ray absorption spectroscopy. Cyanide acts as a competitive inhibitor of reduced CODHII(Ch) with respect to the substrate CO and is therefore expected to mimic the substrate. It inhibits the enzyme reversibly, forming a nickel cyanide. In this reaction, one of the four square-planar sulfur ligands of nickel is replaced by the carbon atom of cyanide, suggesting removal of the micro(2)S from the Ni-(micro(2)S)-Fe1 subsite. Upon reactivation of the inhibited enzyme, cyanide is released, and the square-planar coordination of nickel by 4S ligands is recovered, which includes the reformation of the Ni-(micro(2)S)-Fe1 bridge. The results are summarized in a model of the CO oxidation mechanism at the [Ni-4Fe-5S] active site cluster of CODHII(Ch) from C. hydrogenoformans.

First catalytic synthesis of 7-ferrocenyl-2,4-dioxopyrido [2,3-d]pyrimidines derivatives in water

The reaction of 6-amino-1,3-dimethyluracil with substituted ferrocenyl-ketoalkynes using nickel cyanide as homogeneous catalyst precursor in aqueous alkaline medium, affords 5-substituted-7-ferrocenyl-dioxopyrido[2,3-d]pyrimidines derivatives, in moderate yields under mild conditions.

The low-lying electronic states of nickel cyanide and isocyanide: A theoretical investigation

At different levels of coupled cluster theory optimum structures, energetics, and harmonic vibrational frequencies for several low-lying doublet and quartet electronic states of linear NiCN and NiNC were studied using four contracted Gaussian basis sets, ranging from Ni[6s5p4d2f], CN[4s3p2d] to Ni[8s7p5d3f2g1h], CN[5s4p3d2f1g]. The most reliable predictions were obtained with a relativistic Douglas-Kroll restricted open-shell-based coupled cluster method including singles, doubles, and perturbative triple excitations [DK-R/UCCSD(T)]. This level of theory was used in conjunction with correlation-consistent polarized valence Douglas-Kroll recontracted quadruple-zeta basis sets (cc-pVQZDK). The energetic ordering of the electronic states of NiCN is predicted to be 2delta < 2sigma+ < 2pi < 4delta < 4pi and that of NiNC is 2delta approximately 2sigma+ < 2pi < 4delta < 4pi < 4sigma-. Our theoretical investigation supports the assignment of the ground-state term symbol, the Ni-C stretching frequency, and the bending frequency for the ground electronic state of NiCN by Kingston et al. [J. Mol. Spectrosc. 215, 106 (2002)] and by Sheridan and Ziurys [J. Chem. Phys. 118, 6370 (2003)]. The predicted structure of the 2delta ground state of NiCN, r(e)(Ni-C) = 1.822 angstroms and r(e)(C-N) = 1.167 angstroms, at DK-R/UCCSD(T)/cc-pVQZDK shows excellent agreement with the experimentally determined Ni-C bond length of 1.826 A and less satisfactory agreement for the C-N bond length of 1.153 angstroms [J. Chem. Phys. 118, 6370 (2003)]. It is also concluded that the metal-to-ligand pi back donation is weak or negligible. Additionally, we found that on the 2delta surface the linear cyanide isomer lies lower in energy than the linear isocyanide isomer by 12.2 kcal mol(-1).