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The coordination diversity of a novel N4-ligand and its sodium complex toward cobalt(ii) ions was studied.

The present work describes an efficient reaction of electrochemical phosphorylation of phenylacetylene controlled by the composition of catalytic nanoparticles based on non-noble-metals. The sought-after products are produced via the simple synthetic protocol based on room temperature, atom-economical reactions, and silica nanoparticles (SNs) loaded by one or two d-metal ions as nanocatalysts. The redox and catalytic properties of SNs can be tuned with a range of parameters, such as compositions of the bimetallic systems, their preparation method, and morphology. Monometallic SNs give phosphorylated acetylene with retention of the triple bond, and bimetallic SNs give a bis-phosphorylation product. This is the first example of acetylene and phosphine oxide C-H/P-H coupling with a regenerable and recyclable catalyst.

Redox properties of monoiminoacenaphthenes (MIANs) were studied using various electrochemical techniques. The potential values obtained were used for calculating the electrochemical gap value and corresponding frontier orbital difference energy. The first-peak-potential reduction of the MIANs was performed. As a result of controlled potential electrolysis, two-electron one-proton addition products were obtained. Additionally, the MIANs were exposed to one-electron chemical reduction by sodium and NaBH4. Structures of three new sodium complexes, three products of electrochemical reduction, and one product of the reduction by NaBH4 were studied using single-crystal X-ray diffraction. The MIANs reduced electrochemically by NaBH4 represent salts, in which the protonated MIAN skeleton acts as an anion and Bu4N+ or Na+ as a cation. In the case of sodium complexes, the anion radicals of MIANs are coordinated with sodium cations into tetranuclear complexes. The photophysical and electrochemical properties of all reduced MIAN products, as well as neutral forms, were studied both experimentally and quantum-chemically.

Nickel anions [(MeCN)Ni(CF3)3]− and [Ni(CF3)4]2– were prepared by the formal addition of 3 and 4 equiv, respectively, of AgCF3 to [(dme)NiBr2] in the presence of the [PPh4]+ counterion. Detailed in...

The key intermediate palladacycles (mono-, bi-, and tetranuclear) with phosphonate, acetate, and other counterions in C(sp2)–H phosphonation are analyzed in terms of their redox properties, mutual ...

The reaction between aryl substituted sodium 1,2,3-triphospholides or disodium bis(1,2,3-triphospholide) and [Fe(η6-(C6H5CH3)Cp]+[PF6]- in boiling diglyme results in pure 1,2,3-triphosphaferrocenes 1-3 or bis(1,2,3-triphosphaferrocene) 4, respectively, in good yields. The structure of all obtained 1,2,3-triphosphaferrocenes 1-4 has been extensively studied experimentally (NMR, UV-Vis spectroscopy, and X-ray analysis for 1 and 4) and quantum chemically. The electrochemical properties of 1,2,3-triphosphaferrocenes 1-4 in the solid state were studied for the first time and a reversible one-electron oxidation (E1/2 = 0.52-0.92 V vs. Fc+/Fc) was demonstrated for 1, 3, and 4. In the case of 1,4-bis(5-phenyl-4-(1,2,3-triphospaferrocenyl))benzene 4, consecutive oxidation in the solid state is observed in contrast to other 1,2,3-triphosphaferrocenes 1-3. According to the ESR data, the g-factor of the oxidized bis(1,2,3-triphosphaferrocene), 4 (g = 2.12) is different from the g-factors of oxidized 1,2,3-triphosphaferrocenes 1-3 (g = 2.01). This is the first example of multi(ferrocenyl) systems based on the phosphaferrocene motif, which in turn opens up a new fundamental platform for the preparation of compounds with stimuli-responsive properties.

Rational design and synthesis of efficient metal-organic frameworks (MOFs) as electrode modifiers for energy-related electrocatalytic applications are crucial for the development of clean-energy technologies. The present review focuses on recent work on robust earth-abundant heterogeneous catalysts based on pristine MOFs for the hydrogen evolution reaction (HER) and overall water splitting. These catalysts have been extensively studied as alternatives for noble metal-based ones, demonstrating "hydrogen economy" development prospects. In addition, novel strategies to enhance the conductivity, chemical stability and efficiency of MOF-based electrocatalysts are discussed. The best electrocatalysts even surpass the achievements of the platinum group of metals and MOF-derived catalysts in catalytic performance. The electrolytic cells with MOF-modified electrodes demonstrated excellent catalytic activity and can deliver a high current density at a voltage lower than that using the precious metal-based Pt/C cathodes and IrO2 anodes. In this review article, current approaches to design such MOF and MOF-modified electrode materials are summarized and analyzed.

Copper or silver-catalyzed direct C(sp2)–H/N–H electrochemical cross-coupling of phthalimide and heterocyclic arenes (2-phenylpyridine, benzo[h]quinoline, benzoxazole, and benzothiazole, etc.) for ...

Unusual application of ionic liquids as the promoter for selective white phosphorus tetrahedron opening and reagent in the electrochemical reaction was described. New single-stage electrochemical synthesis of esters of phosphoric acids from white phosphorus in the presence of ionic liquid in alcohol medium has been proposed in mild conditions. One hundred percent conversion of P4 to soluble organophosphorus derivatives was observed. Ionic liquid promotes the opening of a tetrahedron of white phosphorus, acting as an electrophilic reaction component, as well as an electrolyte and a reagent. The dialkylimidazole diethylphosphonate with C–P bond, difficult of access by other approaches, was prepared with good yields.

Metal-organic frameworks [M2L3]n have been synthesized using ferrocene-based ligand bearing phosphinic groups L = 1,1’-ferrocenediyl-bis(H-phosphinic acid)) and M(III) = Eu, Dy. Structures of compl...

The work describes the synthesis of the 2D[Mn(H2O)2(Fc(PHOO)2)⋅2H2O]n using manganese nitrate. The energy of Li-Fc interaction has been estimated quantum-chemically. It was shown that substituent o...

The interaction of manganese(II) phthalocyanine with 7,7,8,8-tetracyanoquinodimethane and its perfluoro derivative proceeds with the oxidation of Mn and the reduction of the acceptor molecules to give the first mixed single crystals of manganese(III) phthalocyanine with TCNQ/F4-TCNQ radical anions. The crystals have unusual structures with C–H⋯π interactions between the ions and their orthogonal arrangement, as well as remarkable redox properties. The charge transfer was proved by spectroscopic and magnetic studies.

New 3D Ni and Co redox-active metal–organic frameworks based on ferrocenyl diphosphinate and 4,4′-bipyridine ligands have been synthesized, characterized by single crystal X-ray diffraction and spectroscopic techniques and explored as stable electrocatalysts capable of meeting two important parameters: the overpotential and Tafel slope (TS) in the hydrogen evolution reaction (HER). The electrochemical studies suggest that the reaction kinetics of a Ni-MOF (1) catalyst is more favorable than that of a Co-MOF (2) catalyst. Particularly, Ni-MOF exhibits better HER performance with an overpotential of 350 mV at a current density of 10 mA cm−2, a small TS of 60 mV dec−1 and superior long-term durability (of up to 10 000 cycles), ranking it among the most active non-noble metal-based molecular electrocatalysts. The introduction of a 4,4′-bpy linker in 2 significantly changes the catalytic properties in an organic or aqueous environment compared to 1D cobalt polymers based on ferrocenyl diphosphinate. For Co-MOF 2, there is a significant decrease in the overvoltage by ∼440 mV in comparison with the 1D Co polymer in an organic medium and by 50 mV in an aqueous medium. The TS changes from 120 to 65 mV dec−1 when moving from 1D CofcdHp to a 3D structure of 2. Thus, a 4,4′-bpy linker reduces the overvoltage and gives more favorable HER kinetics (lower TS). These results provide important guidelines for the rational design of non-precious metal electrocatalysts.

Catalyst capable to operate in cathode and anode spaces simultaneously was found. Electrochemical regeneration of active form of catalyst Co2+bpy (1%) under oxidative as well as reductive condition...

Recent achievements of electrochemical efficient and atom-economical catalytic methods for the formation of aromatic carbon-phosphorus bonds are summarized in this mini-review. Electrochemical reac...

This paper elucidates the redox properties and reactivity of a number of cyclometalated nickel(II) complexes in oxidation processes. Original and robust procedures for the synthesis of nickelacycles with two cyclometalated moieties and halogenated nickelacycles were developed. The complexes were studied by means of electrochemical, ESR, DFT, and single-crystal XRD methods. Notable features of the nickelacycles are unusually low oxidation potentials. Upon electrochemical oxidation the complexes produce carbon–carbon and carbon–heteroatom coupled products, the ratio of which can be tuned by the conditions applied.

New (2-(4-methylpyrazol-1-yl)phenyl) platinum(II) (dibenzoylmethane) Pt(mpp)(dbm) complex based on 4-methylpyrazole was synthesized using a simple scheme. Its crystal structure, spectral and electrochemical properties were studied. The extra pure green (CIE chromacity coordinates X = 0.1419, Y = 0.7444) electroluminescence for OLED structures was obtained.

Two series of isomeric indolizine-based chromophores with isophorone rings as a π-bridge have been synthesized and systematically investigated. The chromophores have a high thermal stability: the decomposition temperature is above 238 °C. For isomers with 1-methyl-2-phenylindolizin-3-yl (MPI-3) donor group higher values of β are predicted in comparison with those having 3-methyl-2-phenylindolizin-1-yl (MPI-1) donor group. This is in good agreement with the experimental and theoretical values of the HOMO-LUMO energy gap. Indolizine-based chromophores with barbituric acceptor and isophorone moieties in the π-bridge demonstrate the combination of good characteristics.

Metal-organic frameworks [M2L3]n have been synthesized using ferrocene-based ligand bearing phosphinic groups L = 1,1′-ferrocenediyl-bis(H-phosphinic acid)) and M(III) = Eu, Dy, Y. Structur...

Over the last several years ionic liquids based on phosphorus salts have been attractive as the subject of many investigations for a myriad of applications in different fields, in particular, in ba...

Nickel (I) complexes of 1,5-diaza-3,7-diphosphacyclooctane PPh2NR2 ligands were obtained from precursor Ni(II) by exhaustive electrolysis of [Ni(PPh2NR2)2]2+ precursors at the Ni(II/I) couple potential and characterized by several techniques. Paramagnetic Ni(I) complexes were investigated by cyclic voltammetry, spectroelectrochemistry UV/Vis and ESR methods at room temperature and in a frozen solution. Catalytic behavior of Ni(I) complex in different ligand environment for hydrogen evolution from acid depends from the ligand nature. The two possible catalytic cycles were proposed depending on the nitrogen substituents in 1,5-diaza-3,7-diphosphacyclooctane.

A new redox active coordination polymer [Co(H2O)2(Fc(PHOO)2)·2H2O]n (Fc = ferrocene) was synthesized by the diffusion method and characterized by single-crystal X-ray diffraction. Phosphinate fragments formed infinite chains connected through ferrocene fragments to 2D PCP associated with cobalt atoms. Additional strong hydrogen bonding via the participation of coordinated and lattice water molecules resulted in the formation of a 3D network. The polymer exhibited water-induced crystal-to-amorphous transformation with chromotropism, as confirmed by spectroscopic techniques, elemental analysis, TGA and XRPD. The explosion of the amorphous phase [Co(Fc(PHOO)2)]n to form water vapor readily led to its conversion into the initial crystalline [Co(H2O)2(Fc(PHOO)2)·2H2O]n with a reverse change of color. The dehydrated form of the polymer selectively sorbed water and could be used as a material with the function of an express dehydrator. Moreover, a modified electrode could qualitatively determine the water content in the solvent at a concentration of 0.05%. Both hydrated and dehydrated forms were evaluated as electrode materials for supercapacitors. The [Co(Fc(PHOO)2)]n (dehydrated form) electrode exhibited high specific capacitance and excellent cycling stability. Its maximum specific capacitance was 2517 F g−1 at a current density of 2 A g−1, and the specific capacitance retention was about 90.1% after 1000 cycles.

New redox active 1D helical coordination polymers M(fcdHp) (M(II) = Zn(1), Co(2)) have been obtained by utilizing the 1,1′-ferrocenylenbis(H-phosphinic) acid (H2fcdHp) ligand and Zn or Co nitrate salts. Complexes 1 and 2 are isomorphic, crystallizing in the chiral space groups P4122 and P4322, respectively. Their redox, electrocatalytic and other properties are described. These compounds incorporated into carbon paste electrodes and exhibited reversible redox reactions, arising from the ferrocenyl moiety. These coordination polymers are efficient as electrocatalysts for the reduction of protons to hydrogen. Using N,N-dimethylformamidium ([DMF(H)+]) as the acid in the acetonitrile solution, Co CP (2) displays a turnover frequency of 300 s−1, which is among the fastest rates reported for any CP electrocatalyst in CH3CN. This high rate of catalytic reaction comes at the cost of the 820–840 mV overpotential at the potential of catalysis. As the hydrogen evolution reaction (HER) catalysts, the CPs exhibited in 0.5 M H2SO4 the overpotential η10 of 340 or 450 mV, onset overpotential of 220 or 300 mV (vs. RHE), Tafel slope of 110 or 120 mV dec−1, correspondingly for 1 and 2, and considerable long-term stability for the HER.

New porous coordination polymer (PCP) has been synthesized using ferrocene-based ligand bearing phosphinic groups (H2fcdHp = 1,1′-ferrocenediyl-bis(H-phosphinic acid)) and aluminum salt. Al-fcdHp was obtained according to a sol–gel approach followed by supercritical CO2 drying. The N2 adsorption properties of aerogel were investigated and N2 amount adsorbed in the pores of PCP reaches 1400 cm3g−1. The aerogel exhibits high surface area of approximately 671 m2/g and redox activity due to ferrocenyl fragment.

A new method of single-stage synthesis of perfluoroalkylated arenes via cross-coupling of bromo (in some cases, chloro) arenes and heteroarenes (derivatives of benzene, pyridine and furan) and organic perfluoroalkyl halides involving complexes of nickel and cobalt in low oxidation state with α-diimines under mild conditions was proposed. Perfluoroalkylated products are obtained in good yields in the presence of М(I)L (M = Ni, Co) catalyst (1–10%) electrochemically generated from M(II)L at room temperature without chemical reductant. It has been found that success of the catalytic process is dependent on the reduction potential of the catalyst. The more negative reduction potential is, the more effective is the catalyst.

A new approach is proposed for ferrocene phosphorylation using α-hydroxylalkylphosphonate as a “masked” phosphorylating agent, by electrochemical reduction of a ferrocene and (Me)2C(OH)P(O)(OC2H5)2 mixture at −50 °C. The method makes it possible to obtain the product of diethyl ferrocenyl phosphonate with a high yield (87–89%) and 100% conversion of the initial phosphonate in one stage. It is evidenced with experiments that ferrocene reduction is carried out with preservation of the iron charge in the ferrocene fragment and with the formation of a cyclopentadienyl ligand radical anion at −3.3 V ref. Ag/AgCl (at −50 °C).

We have developed Ni(III)-doped silica nanoparticles ([(bpy)xNi(III)]@SiO2) as a recyclable, low-leaching, and efficient oxidative functionalization nanocatalyst for aromatic C-H bonds. The catalyst is obtained by doping the complex [(bpy)3Ni(II)] on silica nanoparticles along with its subsequent electrooxidation to [(bpy)xNi(III)] without an additional oxidant. The coupling reaction of arenes with perfluoroheptanoic acid occurs with 100% conversion of reactants in a single step at room temperature under nanoheterogeneous conditions. The catalyst content is only 1% with respect to the substrates under electrochemical regeneration conditions. The catalyst can be easily separated from the reaction mixture and reused a minimum of five times. The results emphasize immobilization on the silica support and the electrochemical regeneration of Ni(III) complexes as a facile route for developing an efficient nanocatalyst for oxidative functionalization.

The new redox active coordination polymer [Cd(H2O)2(fc(PHOO)2)·2H2O]n (fc = 1,1′-ferrocenediyl) was synthesized and structurally characterized by single-crystal X-ray diffraction. In this compound cadmium atoms are bound by phosphinate fragments to give infinite chains, the latter are interconnected by ferrocene groups to form 2D coordination polymer. Electrochemical properties of CP were investigated. It’s found that Cd-polymer is harder to oxidize than its isostructural cobalt analogue. This means that increase in the length of the M − O bond in coordination polymer, oxidation becomes harder.

The efficient catalysis of oxidative alkylation and fluoroalkylation of aromatic C-H bonds is of paramount importance in the pharmaceutical and agrochemical industries, and requires the development of convenient Ag-0-based nano-architectures with high catalytic activity and recyclability. We prepared Ag-doped silica nanoparticles (Ag0/+@SiO2) with a specific nano-architecture, where ultra-small sized silver cores are immersed in silica spheres, 40 nm in size. The nano-architecture provides an efficient electrochemical oxidation of Ag+@SiO2 without any external oxidant. In turn, Ag+@SiO2 5 mol% results in 100% conversion of arenes into their alkylated and fluoroalkylated derivatives in a single step at room temperature under nanoheterogeneous electrochemical conditions. Negligible oxidative leaching of silver from Ag0/+@SiO2 is recorded during the catalytic coupling of arenes with acetic, difluoroacetic and trifluoroacetic acids, which enables the good recyclability of the catalytic function of the Ag0/+@SiO2 nanostructure. The catalyst can be easily separated from the reaction mixture and reused a minimum of five times upon electrochemical regeneration. The use of the developed Ag-0@SiO2 nano-architecture as a heterogeneous catalyst facilitates aromatic C-H bond substitution by alkyl and fluoroalkyl groups, which are privileged structural motifs in pharmaceuticals and agrochemicals.

The synthesized 2D flexible coordination polymer [Mn(H2O)2(Fc(PHOO)2)·2H2O]n was studied for its inhibitory property of redox generation of ●C6F13 from C6F13I.

A convenient oxidant-free phosphorylation of caffeine by dialkyl-H-phosphonates under electrochemical mild conditions in the presence of metal catalyst is proposed. Silver salts, nickel and palladi...

A new approach to phosphorylation of 2-phenylpyridine was proposed. It is possible to obtain the product of diethyl (2-(pyridin-2-yl)phenyl)phosphonate product in good yield (72%) by this method.

The work introduces chemical and electrochemical synthetic routes to obtain Pd(0) nanoparticles (PdNPs) deposited onto silica supports in aqueous media. The former route is performed through reduction of Na 2 [PdCl 4 ] by ascorbic acid in the presence of amino-modified silica nanoparticles (SiO 2 –NH 2 ). The time-dependent variation of pH and the reductant concentration is the simple synthetic route to get uniform deposition of 215 nm sized silica supports by Pd(0) nanoparticles (3–10 nm). The methylviologen-mediated electrochemical synthetic route results in small PdNPs (3–9 nm) located both onto and beyond the silica supports. Thus, the chemical synthetic route provides more homogeneous Pd(0)–SiO 2 –NH 2 aqueous colloids. The results reveal that attractive interactions of amino/ammonium groups of SiO 2 –NH 2 with both [PdCl 4 ] 2− and ascorbate-stabilized Pd(0) seeds are the key reasons for the better Pd(0)-deposition onto silica supports. The chemically deposited Pd(0)–SiO 2 –NH 2 nanoparticles catalyze the chemiluminescence of luminol resulted from the H 2 O 2 -facilitated oxidation in alkaline aqueous solutions.

The two new nickel complexes [Ni(P R 2 N Ph(CH)Ph 2 ) 2 ] 2+ (where R = Ph or o -Py) with cyclic 1,5-diaza-3,7-diphosphacyclooctane ligands have been synthesized. All complexes are effective electrocatalysts for hydrogen production using [(DMF)H] + as proton source in acetonitrile. The bulky benzhydryl substituent at nitrogen atom leads to higher catalytic activity comparison to benzyl. The introduction o -Py substituents at phosphorus as additional basic center is caused by the changing of voltage–current picture and significantly catalytic current enhancement. TOFs being 100 and 15200 s −1 for R = Ph and o-Py, respectively.

Novel cyclic phosphino amino pyridines and their mono- and binuclear Ni(II), Cu(I), and Au(I) complexes have been obtained. It has been shown that catalytic activity of the nickel-(II) complexes in...

A new carbon paste electrode is described, which contains the room temperature ionic liquid (RTIL) tri(tert-butyl)(dodecyl)phosphonium tetrafluoroborate as binder. The advantages of this electrode are a high conductivity, very wide electrochemical window (5.6 V from 2.7 to −2.9 V, one of the widest ever reported for RTILs), stability in time, and reproducibility. This RTIL-carbon paste electrode (CPE) allows determining the current-voltage characteristics of redox-active compounds. Thus, the newly synthesized insoluble compound poly-tris(μ2-1,1′-ferrocenediyl-phenylhydrophosphinato-phenylphosphinato)-iron(III) tetrahydrofuran solvate {μ2-[FeII(η5-C5H4–P(PhOO)(η5-C5H4–P(PhOOH))]3FeIII}·THF was studied, and a quasi-reversible three-electron oxidation could be observed at a potential more positive than that of ferrocene. A comparison of voltammograms on the paraffin-CPE and on the novel RTIL-CPE shows the advantages of the latter.

Nickel complexes of thiophosphorylated calix[4]resorcinols showed high catalytic activity for hydrogen evolution from acidic solutions and stability in the electro-assisted catalysis at the surface of both glassy carbon and Hg-pool electrodes. The conformation of the macrocyclic ligand determines the dimensionality and shape of the catalytically active species generated on the electrode.

Principal achievements and modern trends in the development of new methods of electrocatalytic phosphorylation are analyzed and generalized. Possibilities and advantages of the electrochemical prep...

The present work introduces optimal modifiсation of core-shell composite nanomaterial, where small (2–8 nm) Ag0 nanoparticles are deposited onto large (about 140 nm) silica spheres for application in oxidative catalysis. The size of Ag0 and density of its deposition onto silica spheres was modified by the post treatment of initially deposited Ag0 (about 30 nm) by hydrogen peroxide in specific conditions. The comparison of catalytic effect of the post-treated and initial SN-Ag0 in electrochemical phosphonation of benzo(thia)oxazoles by diethyl phosphite in oxidative conditions revealed the difference between the composite nanoparticles. In particular, the post-treated SNs-Ag0 nanoparticles exhibit efficient catalytic effect in oxidative conditions resulting in facile and green method for synthesis of phosphonated benzooxa(thia)zoles, while no catalytic effect is observed under the use of larger Ag0 nanoparticles deposited onto silica spheres. The use of Ag0-based nanomaterial in oxidative catalysis had been never demonstrated before.

Principal achievements and modern trends in the development of new methods of electrocatalytic fluoroalkylation are analysed and generalised. Possibilities and advantages of the electrochemical preparation of fluoroalkyl compounds are demonstrated. The attention is focused on the fluoroalkylation of olefins, σ-fluororganonickel complexes reactivity, aromatic perfluoroalkylation, fluoroalkyl phosphines and phosphine oxides synthesis, ligand directed C–H-fluoroalkylation.

The bis-chelate dichloride iron(II) complex (1) with a 1,5-diaza-3,7-diphosphacyclooctane ligand (PPh2NBn2) was synthesized and characterized by single crystal X-ray diffraction (XRD). Redox proper...

The solid-state structure and redox properties of bis-chelate dibromide nickel(II) complex (1) with a 1,5-diaza-3,7-diphosphacyclooctane ligand (PPh2NBn2) was reported.

A series of multinuclear Cu(I) complexes (CuI)xLy, namely the previously reported (CuI)6L2 and (CuI)2L′ and novel (CuI)2L2, where L and L′ are 1,5-di(R)-3,7-bis(2-pyridine-2′-yl)ethyl-1,5-diaza-3,7-diphosphacyclooctanes are introduced. Both dissociative and oxidative behavior of the complexes in DMSO and DMF solutions are correlated with the time-dependent changes in their phosphorescence originated from 3(X + M)LCT transitions. The instability of butterfly-like (CuI)2L′ resulting in its oxidative degradation in DMSO and transformation into (CuI)L′2 in DMF solutions differentiates it from more stable linear complexes (CuI)6L2 and (CuI)2L2. The complexes (CuI)2L2 and (CuI)L2 produced by the dissociation of (CuI)6L2.in DMSO and DMF solutions are regarded as structural motifs responsible for both reversible blue-shifting by 10 nm of the emission band and the decrease in the excited states lifetime values upon the heating of the solutions within 293–333 K. This temperature-induced behavior along with the phosphorescence character of the emission of both complexes points to thermally activated delayed fluorescence as the reason for the reversible temperature-induced spectral changes of hexanuclear (CuI)6L2. Smaller nuclearity of (CuI)2L2 is the reason for partial reversibility of the spectral changes.