Reinecke Salt Research Articles

Analytical characterization of choline chloride in oilfield process waters and commercial samples by capillary electrophoresis

In this study, a rapid and sensitive method using capillary electrophoresis with indirect UV detection and minimal sample pretreatment was developed and evaluated to analyze choline chloride in oilfield process water samples. To improve peak resolution and separation of choline chloride from other cations present in the samples, the addition of a cationic visualization agent in the background electrolyte, imidazole, and a complexing agent, 18-crown-6, were introduced. Other factors affecting separation and sensitivity were also investigated. Under optimized conditions, choline chloride was baseline separated (<7 min) from common cationic adulterants in commercial choline chloride products with a peak resolution of >1.5 between adjacent peaks. The limits of detection (signal-to-noise ratio = 3) and quantitation (signal-to-noise ratio = 10) were 14.7 and 48.9 mg L−1, respectively. The peak area and migration time’s intraday and interday precision (percent RSD) were all <15%, and the recoveries ranged from 79.4% to 115.2% at different spiking levels. Finally, statistical (Student’s t-test) comparison of the choline chloride content data of oilfield process water samples from the proposed capillary electrophoresis (CE) method compare favourably with traditional methods such as liquid chromatography – mass spectrometry (LC–MS) and Reinecke salt gravimetry.

Spectrophotometric and atomic absorption spectrometric determination of cephalexin and cephradine in dosage forms

This paper describes two simple, sensitive and selective spectrophotometric and atomic absorption spectrometric (AAS) procedures for the determination of two compounds of cephalosporins (Cephalexin monohydrate and Cephradine). These procedures are based on the formation of ion-pair complexes between the drugs and ammonium reineckate. The formed precipitates are quantitatively determined either spectrophotometrically or by AAS procedures. The methods consist of reacting drugs with Reinecke's salt in an acidic medium at a temperature of 25 ± 2°C. The spectrophotometric procedure (procedure I) is based on dissolving the formed precipitate with acetone. The volume was completed quantitatively and absorbance of the solution was measured at 525 nm against blank. Also, the AAS procedures (procedure II) are quantitatively determined directly or indirectly through the chromium precipitate formed or the residual unreacted chromium in the filtrate at 358.6 nm. The optimum conditions for precipitation have been carefully studied. Beer's law is observed for the studied drugs in the ranges 0.1-1.5 mg mL-1 or 5-70 μg mL-1 using spectrophotometric or AAS methods, with correlation coefficients ≥ 0.9965, respectively. Both procedures I and II were accurate and precise when applied to the analysis of the cited cephalosporins in different dosage forms with good recovery percent ranged from 98.90 ± 0.94 to 100.15 ± 0.97 without interference from additives.

Liquid membrane/polyaniline film coated glassy carbon sensor for highly sensitive and selective determination of fluvoxamine in pharmaceutical and biological samples

A novel and very sensitive potentiometric sensor with excellent electrochemical properties was fabricated for the determination of fluvoxamine. The sensor is based on the use of the PVC-membrane containing ion-association complex of fluvoxamine with reinecke salt coated on the glassy carbon electrode which was modified with polyaniline as a conductive polymeric film. The proposed sensor exhibits a Nernstian slope of 58.9mV per decade for fluvoxamine over a wide concentration range of 1.8×10−7–1.3×10−3M, with a low detection limit of 7.8×10−8M. The sensor has a fast response time, excellent reproducibility and long life time. It can be used within the pH range of 4.0–7.5 in a long time period. The sensor possesses a high selectivity toward a large variety of inorganic and organic co-existing species. The effect of temperature on the sensor potential response was studied and the isothermal coefficient of the sensor was calculated. The sensor has a good thermal stability within the studied temperature range. The developed sensor was used as an indicator electrode in potentiometric titration of fluvoxamine with sodium tetraphenylborate. The sensor was successfully applied in the determination of fluvoxamine in pharmaceutical solution, blood serum and urine samples.

Diaquatetrakis(dimethyl sulfoxide-κO)cobalt(II) bis[diamminetetrakis(thiocyanato-κN)chromate(III)] dimethyl sulfoxide hexasolvate dihydrate

The solvated title salt, [Co(C2H6OS)4(H2O)2][Cr(NCS)4(NH3)2]·6C2H6OS·2H2O, is build up from a complex [Co(DMSO)4(H2O)2]2+ cation (where DMSO is dimethyl sulfoxide), two Reinecke's Salt anions, i.e. [Cr(NCS)4(NH3)2]−, as the complex counter-ions, together with solvent molecules (six DMSO and two water). The crystal packing consists of a branched three-dimensional system of hydrogen bonds involving the DMSO and water solvent molecules, the S atoms of the thiocyanate ligands, and the coordinating NH3 and H2O molecules.

Radiative transfer approach using Monte Carlo Method for actinometry in complex geometry and its application to Reinecke salt photodissociation within innovative pilot-scale photo(bio)reactors

In this article, a complete radiative transfer approach for estimating incident photon flux density by actinometry is presented that opens the door to investigation of large-scale intensified photoreactors. The approach is based on an original concept: the analysis of the probability that a photon entering the reaction volume is absorbed by the actinometer. Whereas this probability is assumed to be equal to one in classical actinometry, this assumption can no longer be satisfied in many practical situations in which optical thicknesses are low. Here we remove this restriction by using most recent advances in the field of radiative transfer Monte Carlo, in order to rigorously evaluate the instantaneous absorption-probability as a function of conversion. Implementation is performed in EDStar, an open-source development environment that enables straightforward simulation of reactors with any geometry (directly provided by their CAD-file), with the very same Monte Carlo algorithm. Experimental investigations are focused on Reinecke salt photodissociation in two reactors designed for the study of natural and artificial photosynthesis. The first reactor investigated serves as reference configuration: its simple torus geometry allows to compare flux densities measured with quantum sensors and actinometry. Validations and analysis are carried out on this reactor. Then, the approach is implemented on a 25L photobioreactor with complex geometry corresponding to one thousand light-diffusing optical fibers distributing incident photons within the reaction volume. Results show that classical actinometry neglecting radiative transfer can lead to 50 percent error when measuring incident flux density for such reactors. Finally, we show how this radiative transfer approach paves the way for analyzing high conversion as a mean to investigate angular distribution of incident photons.

Trans-Chloridobis-(ethane-1,2-di-amine-κ(2) N,N')(thio-cyanato-κN)cobalt(III) diammine-tetra-kis-(thio-cyanato-κN)cromate(III).

The title ionic complex [CoCl(NCS)(C2H8N2)2][Cr(NCS)4(NH3)2], which crystallizes as a non-merohedral twin, is build up of a complex cation [CoCl(NCS)(en)2]+ (en is ethane-1,2-di­amine) and the Reinecke’s salt anion [Cr(NCS)4(NH3)2]− as complex counter-ion. A network of N—H⋯S and N—H⋯Cl hydrogen bonds, as well as short S⋯S contacts [3.538 (2) and 3.489 (3) Å], between the NCS groups of the complex anions link the mol­ecules into a three-dimentional supra­molecular network. Intensity statistic indicated twinning by non-mero­hedry with refined weighs of twin components are 0.5662:0.4338.

Hexakis(dimethylformamide-κO)manganese(II) (dimethylformamide-κO)pentakis(thiocyanato-κN)chromate(III)

The title compound, [Mn(C3H7NO)6][Cr(NCS)5(C3H7NO)], was obtained unintentionally as a product of an attempted synthesis of heterometallic complexes based on Reineckes anion using manganese powder, Reineckes salt and 1-(2-hy­droxy­eth­yl)tetra­zole as starting materials. The crystal structure of the complex consists of an [Mn(dmf)6]2+ cation and a [Cr(NCS)5(dmf)]2− anion (dmf = dimethyl­formamide). The MnII and CrIII atoms show a slightly distorted octa­hedral MnO6 and CrN5O coordination geometries with adjacent angles in the range 85.29 (13)–95.96 (14)°.

Tris(1,10-phenanthroline-κ2N,N′)iron(II) bis[(1,10-phenanthroline-κ2N,N′)tetrakis(thiocyanato-κN)chromate(III)] acetonitrile trisolvate monohydrate

Single crystals of the title heterometallic compound, [Fe(C12H8N2)3][Cr(NCS)4(C12H8N2)]2·3CH3CN·H2O or [Fe(Cphen)3][Cr(NCS)4(phen)]2·3CH3CN·H2O, were pre­pared using the one-pot open-air reaction of iron powder, Reineckes salt and 1,10-phenanthroline (phen) in acetonitrile. The asymetric unit consists of an [Fe(phen)3]2+ cation, two [Cr(phen)(NCS)4]− anions, three acetonitrile solvent mol­ecules and a water mol­ecule. The Fe and Cr atoms both show a slightly distorted octa­hedral FeN6 and CrN6 coordination geometry with adjacent angles in the range 79.67 (12)–95.21 (12)°. No classical hydrogen bonding involving the water molecule is observed.

Bis{μ2-2-[(2-hydroxyethyl)(methyl)amino]ethanolato}bis(μ3-N-methyl-2,2′-azanediyldiethanolato)tetrakis(thiocyanatato-κN)dichromium(III)dimanganese(II) dimethylformamide tetrasolvate

The heterometallic title complex, [Cr2Mn2(C5H11NO2)2(C5H12NO2)2(NCS)4]·4C3H7NO, was prepared using manganese powder, Reineckes salt, ammonium thio­cyanate and a non-aqueous solution of N-methyl­diethano­lamine in air. The centrosymmetric mol­ecular structure of the complex is based on a tetra­nuclear {Mn2Cr2(μ-O)6} core. The tetra­nuclear complex mol­ecule and the two uncoordinated dimethyl­formamide mol­ecules are linked by O—H⋯O hydrogen bonds, while the two other mol­ecules of dimethyl­formamide do not participate in hydrogen bonding.

Diammine(2,2′-bipyridine)bis(thiocyanato-κN)cobalt(III) diamminetetrakis(thiocyanato-κN)chromate(III) acetonitrile disolvate

The new heterometallic title complex, [Co(NCS)2(C10H8N2)(NH3)2][Cr(NCS)4(NH3)2]·2CH3CN, has been prepared using the open-air reaction of cobalt powder, Reineckes salt and 2,2′-bipyridine (dpy) in acetonitrile. The crystal structure consists of discrete cationic [Co(NCS)2(NH3)2(dpy)]+ and anionic [Cr(NCS)4(NH3)2]− building blocks, both with 2 symmetry, and acetonitrile solvent mol­ecules, which are linked together by N—H⋯N hydrogen bonds, forming extended supra­molecular chains. Furthermore, N—H⋯S, C—H⋯S and C—H⋯N hydrogen bonds inter­link neighbouring chains into a three-dimensional framework. The Co atom is in an elongated octa­hedral coordination environment with two N atoms from the dpy ligands and two NCS-groups in the equatorial plane and with two NH3 mol­ecules at the axial positions. The CrIII ion is octa­hedraly coordinated by two NH3 mol­ecules at the axial positions and four NCS-groups in the equatorial plane. Intensity statistics indicated non-merohedral twinning with the twin matrix [100; 00; 0]. The refined ratio of the twin components is 0.530 (1):0.470 (1).

Co-crystallization of coordination compounds through second-coordination sphere interactions

The mononuclear complexes belonging to the [M(valXn)]0/+ family [H2valXn are bicompartmental ligands derived from o-vanillin and 1,2- or 1,3-diamines; M = Ni(II), Cu(II), Au(III)] can efficiently act as receptors towards various hydrogen bond donors. The co-crystallization processes between [Ni(valXn)] complexes and ammonium salts (NH4Z, Z− = ClO4−; PF6−; C6H5NH3ClO4) led to different supramolecular arrangements in the crystals depending on the host : guest molar ratio used in reactions. For a 2 : 1 stoichiometry, supramolecular dimers were obtained in the crystals: 2[Ni(valen)]·NH4Z (Z− = ClO4−, 1a; Z− = PF6−, 1b), 2[Ni(valphen)]·NH4ClO4·CH3OH 1c, 2[Ni(valmen)]·C6H5NH3ClO43, while for a 1 : 1 stoichiometry a supercomplex with a quadruple deck architecture resulted: 4[Ni(valen)]·3NH4ClO42. The co-crystallization of the Reinecke salt with mononuclear complexes from the [M(valXn)] family affords the following crystals: [Ni(valen)]2·NH4[Cr(NCS)4(NH3)2]·CH3OH 4, [Ni(valdmpn)]2·NH4[Cr(NCS)4(NH3)2]·2H2O 5, and [Cu(valpn)]·NH4[Cr(NCS)4(NH3)2]·CH3CN 6, in which the [M(valXn)] complexes interact with the ammonium ions and ammonia ligands, resulting in supramolecular chains. The composition and the topology of the supramolecular chain can be changed by replacing the ammonium ion from the Reinecke salt with a cationic receptor, [Au(valpn)]+ : [Au(valpn)][Cr(NCS)4(NH3)2] 7.

CrIII−CrIIIInteractions in Two Alkoxo-Bridged Heterometallic Zn2Cr2Complexes Self-Assembled from Zinc Oxide, Reinecke’s Salt, and Diethanolamine

Two new tetranuclear complexes, [Zn(2)Cr(2)(NCS)(4)(Dea)(2)(HDea)(2)].4DMSO (1; DMSO = dimethyl sulfoxide) and [Zn(2)Cr(2)(NCS)(4)(Dea)(2)(HDea)(2)].2CH(3)CN (2), were prepared from zinc oxide, Reinecke's salt, NH(4)[Cr(NCS)(4)(NH(3))(2)].H(2)O, ammonium thiocyanate, and a nonaqueous solution of diethanolamine (H(2)Dea) in a reaction carried out under open air. Both compounds have similar centrosymmetric crystal structures based on a tetranuclear {Zn(2)Cr(2)(mu(3)-O)(2)(mu-O)(4)} core. Variable-temperature magnetic susceptibility measurements of 1 and 2 show weak antiferromagnetic coupling between chromium centers. The magnetic data and high-field, high-frequency electron paramagnetic resonance spectra were analyzed in terms of the spin Hamiltonian H = JS(1).S(2) - j(S(1).S(2) + mu(B)B{g(1)}S(1) + D(Cr){S(z1)(2) - S(1)(S(1) + 1)/3} + E(Cr)(S(x1)(2) - S(y1)(2)) + mu(B)B{g(2)}S(2) + D(Cr){S(z2)(2) - S(2)(S(2) + 1)/3} + E(Cr)(S(x2)(2) - S(y2)(2)) + D(12){S(z1)S(z2) - S(1).S(2)/3} + E(12)(S(x1)S(x2) - S(y1)S(y2)) with J = 13.7 cm(-1), j = 1.1 cm(-1), D(Cr) = 0.3864 cm(-1), E(Cr) = -0.1104 cm(-1), D(12) = -0.1873 cm(-1), and E(12) = -0.0155 cm(-1) for 1 and J = 9.4 cm(-1), j = 0.8 cm(-1), D(Cr) = 0.3564 cm(-1), E(Cr) = -0.0647 cm(-1), D(12) = -0.1850 cm(-1), and E(12) = -0.0112 cm(-1) for 2. Density functional theory (DFT) calculations were employed to calculate the zero-field splitting on Cr(3+) ions. Calculations of the exchange integrals J were attempted by using the "broken-symmetry" DFT method.

Indigotine, azorubine, and cochineal red as photoprotectors of manidipine

Background: The calcium antagonists from the group of 1,4-dihydropyridine (DHP) derivatives are photolabile, and the products of their photochemical decomposition have no pharmacological activity. Like the other DHP derivatives, after exposure to light, manidipine undergoes decomposition leading to a weakening of the pharmacological activity. Method: The protective influence of selected dyes on manidipine has been tested. The photodegradation of manidipine was performed according to the first version of the ICH Guideline for photostability testing. The solutions were illuminated by a high-pressure lamp HBO-200, and the methods used for evaluation of manidipine photodegradation were HPLC, HPLC–MS, and UV–vis spectrophotometry. Quantitative evaluation of photodegradation was made on the basis of the quantum yields of the processes with the use of Reinecke salt as a chemical actinometer. Results: Results have shown that all the dyes studied, indigotine, azorubine, and cochineal red, slow down the process of manidipine photodegradation, and the most effective is azorubine. The role of the dyes has been determined on the basis of the Stern–Volmer dependence. Conclusion: The dyes studied, indigotine, azorubine, and cochineal red, can be potential photoprotectors of manidipine as they quench the excited states of the compound.

Structural and magnetic studies of tetranuclear heterometallic M/Cr (M = Co, Mn) complexes self-assembled from zerovalent cobalt or manganese, Reineckes salt and diethanolamine

Four novel heterometallic complexes [Co 2Cr 2(NCS) 4(HDea) 2(Dea) 2]·4dmf ( 1), [Co 2Cr 2(NCS) 4(HDea) 2(Dea) 2]·4dmso ( 2), [Mn 2Cr 2(NCS) 4(HDea) 2(Dea) 2(dmf) 2]·2dmf ( 3) and [Mn 2Cr 2(NCS) 4(HDea) 2(Dea) 2(dmso) 2]·4dmso ( 4) have been prepared using zerovalent cobalt ( 1, 2) or manganese ( 3, 4), Reineckes salt, ammonium thiocyanate and a non-aqueous solution of diethanolamine (H 2Dea) in air. The single X-ray analysis reveals that all compounds have similar centrosymmetric crystal structures based on a tetranuclear {M 2Cr 2(μ 3-O) 2(μ-O) 4} (M = Co, Mn) core. Variable-temperature magnetic susceptibility measurements of 1, 2 and 4 show antiferromagnetic coupling between the magnetic centers, while 3 exhibits a ferromagnetic behavior.

An extremely rare example of asymmetric tetranuclear core {M4(μ3-X)2(μ-X)4} in a novel alkoxo-bridged heterometallic Cr/Cd complex

A novel heterometallic tetranuclear complex [Cr(3)Cd(NCS)(4)(H(2)tea)(Htea)(3)].3CH(3)OH () has been prepared using cadmium oxide, Reinecke's salt, ammonium thiocyanate and a methanol solution of triethanolamine (H(3)tea) in air. Crystallographic investigations reveal that the molecular structure of the complex is based on an uncommon asymmetric {Cr(3)Cd(mu(3)-O)(2)(mu-O)(4)} core with firstly observed terminal coordination of the NCS-groups in such molecular structure type. A network of O-HO hydrogen bonds as well as SS interactions link the molecules into a two-dimensional supramolecular network. Variable-temperature (1.8-300 K) magnetic susceptibility measurements show a change of the mu(B) value at low temperature, indicative of antiferromagnetic interactions (J = -7.45 cm(-1)) between chromium(iii) centers.

Direct synthesis of an heterometallic {MnII3CrIII4} wheel by decomposition of Reineckes salt

A new heterometallic Mn/Cr molecular wheel complex has been synthesized using zerovalent manganese, Reineckes salt, ammonium thiocyanate and triethanolamine (H(3)tea) as starting materials. The compound [Mn(3)Cr(4)(NCS)(6)(Htea)(6)] (1) has been characterized in terms of its electrochemical, IR and EPR spectroscopic as well as its magnetic properties. The magnetic susceptibility and magnetization data were treated simultaneously during the optimization routine and resulted in J(Mn-Cr) = +0.43 cm(-1), J(Cr-Cr) = -4.75 cm(-1), J(Mn-Mn) = +1.78 cm(-1), g(eff) = 1.878 with the ground state S = 15/2.

A flow injection system, comprising a biosensor based on a screen-printed carbon electrode containing Meldola’s Blue–Reinecke salt coated with glucose dehydrogenase, for the measurement of glucose

A biosensor for the measurement of glucose in serum has been developed, based on a screen-printed carbon electrode modified with Meldola’s Blue–Reinecke salt, coated with the enzyme glucose dehydrogenase (from Bacillus sp.), and nicotinamide adenine dinucleotide coenzyme (NAD+). A cellulose acetate layer was deposited on top of the device to act as a permselective membrane. The biosensor was incorporated into a commercially available, thin-layer, amperometric flow cell operated at a potential of only +0.05V versus Ag/AgCl. The mobile phase consisted of 0.2M phosphate buffer (pH 7.0) containing 0.1M potassium chloride solution, and a flow rate of 0.8mlmin−1 was used throughout the investigation. The biosensor response was linear over the range of 0.075–30mM glucose, with the former representing the detection limit. The precision of the system was determined by carrying out 20 repeat injections of a 5-mM glucose standard, and the calculated coefficient of variation was 3.9%. It was demonstrated that this biosensor system could be applied to the direct measurement of glucose in serum without pretreatment. Therefore, this would allow high-throughput analysis, at low cost, for this clinically important analyte.

Indigotine, azorubine, and cochineal red as photoprotectors of manidipine

The calcium antagonists from the group of 1,4-dihydropyridine (DHP) derivatives are photolabile, and the products of their photochemical decomposition have no pharmacological activity. Like the other DHP derivatives, after exposure to light, manidipine undergoes decomposition leading to a weakening of the pharmacological activity. The protective influence of selected dyes on manidipine has been tested. The photodegradation of manidipine was performed according to the first version of the ICH Guideline for photostability testing. The solutions were illuminated by a high-pressure lamp HBO-200, and the methods used for evaluation of manidipine photodegradation were HPLC, HPLC-MS, and UV-vis spectrophotometry. Quantitative evaluation of photodegradation was made on the basis of the quantum yields of the processes with the use of Reinecke salt as a chemical actinometer. Results have shown that all the dyes studied, indigotine, azorubine, and cochineal red, slow down the process of manidipine photodegradation, and the most effective is azorubine. The role of the dyes has been determined on the basis of the Stern-Volmer dependence. The dyes studied, indigotine, azorubine, and cochineal red, can be potential photoprotectors of manidipine as they quench the excited states of the compound.

Application of isotachophoretic and conductometric methods for neomycin trisulphate determination

AbstractDetermination of neomycin trisulphate (NMS) in a dosage form (Neox and Neosol) was carried out by capillary isotachophoresis (cITP) with conductometric detection. The following electrolytes: leading: 10 mmol dm−3 sodium acetate + 0.08 % hydroxyethylcelulose (HEC) and acetic acid to pH = 5.5, and terminating: 10 mmol dm−3 β-alanine were tested for isotachophoretic separation of NMS. The calibration curve was linear over the range of 10.00 mg dm−3 to 100.00 mg dm−3 with LOD = 5.69 mg dm−3 and LOQ = 18.96 mg dm−3. The results were compared to the conductometric determination of NMS with: ammonium molybdate (VI), silver nitrate (V) and Reinecke salt. Good accuracy was obtained from conductometric titration of NMS with Reinecke salt, the recoveries being as follows: 100 % (RSD = 1.99 %); 96.17 % (RSD = 2.10 %) and 95.22 % (RSD = 1.55 %) for NMS in pure form, Neosol and Neox, respectively.

Novel heterometallic Cu(II)/Cr(III) complex with unique open-chain N-ligand produced in conditions of direct template synthesis

The one-pot self-assembly reaction of copper powder, Reineckes salt, acetone and tris(2-aminoethyl)amine (tren) in dmso affords to obtain a heterometallic compound [Cu(trenac)][Cr(NCS) 4(NH 3) 2](NCS) · 6dmso with novel Schiff-base ligand N-(2-{[(1 E)-3-amino-1,3-dimethylbutylidene]amino}ethyl)- N-(2-aminoethyl)ethane-1,2-diamine (trenac). The ligand trenac is generated by metal-directed condensation of tren, acetone and ammonia, formed during the synthetic procedure. X-ray structural investigations showed that the complex consists of [Cu(trenac)] 2+ cations, anions of the Reineckes salt [Cr(NCS) 4(NH 3) 2] −, uncoordinated thiocyanate groups and dmso molecules, which are held together by electrostatic forces and hydrogen-bonded interactions. The compound was characterized by EPR spectroscopic and magnetic susceptibility measurements.