Addition Of NH4PF6 Research Articles

Beyond the Norm: Synthesis and Electrochemical Study of High Concentrated NaPF6 Electrolytes

The global drive towards decarbonisation means there is increasing need for large-scale energy storage, which has focussed research efforts into sodium-ion batteries (SIBs).1 SIBs are well suited to grid-storage applications due to the wide abundance, even distribution and low cost of sodium deposits.2 This contrasts to the better known and understood lithium-ion batteries (LIBs), where lithium is much less abundant. Additionally, the use of sodium has other sustainability implications, which are desirable for grid-scale applications, as it allows cobalt-free cathodes to be used and the copper current collectors at the anode to be replaced by aluminium.Currently SIBs use NaPF6 as the chosen electrolyte salt,3 however commercial supplies of this are often of low-grade and contain NaF (a hydrolysis product of NaPF6), making it unsuitable for battery use.4 Alternatively, pre-made electrolyte solutions of NaPF6 may be purchased, but the cost can be prohibitive and limits solvent exploration.Herein, this talk will detail the synthesis of high-grade NaPF6 from the addition of NH4PF6 with sodium metal in THF solvent. By performing the reaction under anhydrous conditions, NaPF6 can be prepared in the absence of hydrolysis products (NaF), as confirmed by solid-state NMR spectroscopy and powder X-ray diffraction. With high-grade NaPF6 in hand, we have looked at the effects of using higher concentration electrolyte solutions of NaPF6 (>1 M) in ethylene carbonate:diethyl carbonate (EC:DEC 1:1 v/v) solvent. This showed the degradation dynamics of sodium metal-electrolyte interface are different for more concentrated (>1 M) electrolytes, although there is a trade-off with bulk conductivity compared to 1 M solutions. Lastly, the performance of the synthesized NaPF6 has been tested in commercial 2- and 3-electrode pouch cells by Faradion Ltd, UK.5

Formation of Iridium(III) and Rhodium(III) Amine, Imine, and Amido Complexes Based on Pyridine-Amine Ligands: Structural Diversity Arising from Reaction Conditions, Substituent Variation, and Metal Centers.

Herein, we present the different coordination modes of half-sandwich iridium(III) and rhodium(III) complexes based on pyridine-amine ligands. The pyridyl-amine iridium(III) and rhodium(III) complexes, the corresponding oxidation pyridyl-imine products, and 16-electron pyridyl-amido complexes can be obtained through the change in reaction conditions (nitrogen/adventitious oxygen atmosphere, reaction time, and solvents) and structural variations in the metal and ligand. Overall, the reaction of pyridine-amine ligands with [(η5-C5(CH3)5)MCl2]2 (M = Ir or Rh) in the presence of adventitious oxygen afforded the oxidized pyridyl-imine complexes. The possible mechanism for the oxidation of iridium(III) and rhodium(III) amine complexes was confirmed by the detection of the byproduct hydrogen peroxide. Moreover, the formation of pyridyl-amine complexes was favored when nonpolar solvent CH2Cl2 was used instead of CH3OH. The rarely reported complex with [(η5-Cp*)IrCl3] anions can also be obtained without the addition of NH4PF6. The introduction of the sterically bulky i-Bu group on the bridge carbon of the ligand led to the formation of stable 16-electron pyridyl-amido complexes. The pyridyl-amine iridium(III) and rhodium(III) complexes were also synthesized under a N2 atmosphere, and no H2O2 was detected in the whole process. In particular, the aqueous solution stability and in vitro cytotoxicity toward A549 and HeLa human cancer cells of these complexes were also evaluated. No obvious selectivity was observed for cancer cells versus normal cells with these complexes. Notably, the represented complex 5a can promote an increase in the reactive oxygen species level and induce cell death via apoptosis.

Complexes of Pd(II), η6-C6H6Ru(II), and η5-Cp*Rh(III) with Chalcogenated Schiff Bases of Anthracene-9-carbaldehyde and Base-Free Catalytic Transfer Hydrogenation of Aldehydes/Ketones and N-Alkylation of Amines

The condensation of 2-(phenylsulfanyl)ethylamine and 2-(phenylselenyl)ethylamine with anthracene-9-carbaldehyde resulted in Schiff bases [PhS(CH2)2C═N-9-C14H9](L1) and [PhSe(CH2)2C═N-9-C14H9] (L2), respectively. Na2[PdCl4] treatment of L1/L2 in acetone–water mixture for 3 h at room temperature gave palladacycle [PdCl(C–, N, S/Se)] (1/2; L1/L2–H = (C–, N, S)/(C–, N, Se)). The reaction of [(η6-C6H6)RuCl(μ-Cl)]2 with L1/L2 in methanol for 8 h at room temperature (followed by addition of NH4PF6) afforded half-sandwich complex [(η6-C6H6)Ru(L)Cl][PF6], 3/4: (L = L1/L2 ≡ (N, E) ligand). The reaction of [(η5-Cp*)RhCl(μ-Cl)]2 with L1 /L2 in the presence of CH3COONa at 50 °C (followed by treatment with NH4PF6) resulted in [(η5-Cp*)Rh(L-H)][PF6], 5/6: (L = L1/L2). On carrying out the reaction of [(η5-Cp*)RhCl(μ-Cl)]2 with these ligands at room temperature and in the absence of CH3COONa, complex [(η5-Cp*)Rh(L)Cl][PF6], 7/8 (L = L1/L2 ≡ (N, E) ligand), was formed. Complexes 1–8 were authenticated with 1H, 13C{1H}, and...

Synthesis and coordination chemistry of N-doped polyphenylenes

The N-doped polyphenylene derivatives are expected to show interesting optical, electrochemical and structural properties. 8-Azafluoranthene ligands (2a) and (2b) were prepared by a Diels-Alder cycloaddition reaction between 2-cyanopyridine and the corresponding cyclopentadienone. Treatment of [Mo(CO)4(piperidine)2] with ligands (2) gave the tetracarbonylmolybdenum(0) complexes [Mo(CO)4(2)] (3), in which the ligand is coordinated to the metal through both nitrogen donors. Treatment of (2b) with [Pd(OAc)2] gave the cyclometallated Pd(II) complex [Pd(OAc)(L)] (4a), in which L is an anionic terdentate-ligand. Treatment of (2b) with [PdCl2(NCPh)2] gave the complex [PdCl(L)] (4b). The acetate group of (4a) can be easily replaced by halide ions to give [PdCl(L)] (4b), [PdBr(L)] (4c) and [PdI(L)] (4d), respectively. Treatment of (4a) with DMAP and PPh3 in dichloromethane and the subsequent addition of NH4PF6 in methanol gave the corresponding salts [Pd(DMAP)(L)]PF6 (6a) and [Pd(PPh3)(L)]PF6 (6b), respectively. DOI: http://dx.doi.org/10.4038/ouslj.v6i0.4114 OUSL Journal (2010) Vol. 6, (pp. 59- 74)

Annulation of an Iridabenzene through Formal Cycloaddition Reactions with Organonitriles

The cationic iridacyclopentadiene complex [Ir(C4H4)(CS)(MeCN)(PPh3)2][CF3SO3] (2), which is derived from the reaction between [Ir(CS)(MeCN)(PPh3)2][CF3SO3] (1) and ethyne, undergoes a thermally induced migratory insertion reaction involving the thiocarbonyl ligand to form the cationic iridabenzene [Ir(C5H4{S-1})(MeCN)(PPh3)2][CF3SO3] (3) in very high yield. The addition of methyl triflate to this iridabenzene in the presence of NCMe results in methylation of the sulfur atom, and the red dicationic iridabenzene [Ir(C5H4{SMe-1})(MeCN)2(PPh3)2][PF6]2 (4) is obtained after the addition of NH4PF6. Upon treatment of 3 with RCN (R = Me or p-tolyl) and acid, a cyclization reaction ensues between the organonitrile and the η2-C(S)Ir function of the iridabenzene to give the corresponding iridabenzothiazolium complexes [Ir(C5H4{NH═C(R)S-1})(RCN)(PPh3)2][PF6]2 [R = Me (6a); p-tolyl (6b)], where the iridium occupies a ring junction position.

Ruthenium(II)-arylazoimidazole-8-hydroxyquinolinate complexes: Synthesis, spectral study (H, C, COSY, HMQC-NMR) and redox properties

The reaction of [Ru(OH2)2(RaaiR′)2]2+ (RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R-C6H4-N=N-C3H2NN(1)-R′, R = H (1), Me (2), Cl (3); R′ = Me (a), Et (b), CH2Ph (c)) with 8-quinolinol (HQ) in acetone solution followed by the addition of NH4PF6 has afforded violet coloured mixed ligand complexes of the composition [Ru(Q)(RaaiR′)2](PF6). The maximum molecular peak of 1b is observed at m’z 790 (50%) in the ESI mass spectrum. Ir spectra of the complexes show -C=N- and -N=N- stretching near at 1590 and 1370 cm−1. The 1H NMR spectral measurements suggest methylene, -CH2−, in RaaiEt gives a complex AB type while in RaaiCH2Ph it shows AB type quartets. Considering the arylazoimidazole and oxine moitie there are twenty different carbon atoms in the molecule which gives a total of twenty different peaks in the C13 NMR spectrum of complex 1a. In the 1H-1H COSY spectrum of the present complexes, absence of any off-diagonal peaks extending from δ = 14.12 and 9.55 ppm confirm their assignment of no proton on N(1) and N(3) respectively. Contour peaks in the 1H-13C HMQC spectrum in the present complexes, the absence of any contours at δ = 157.12, 160.76, 155.67 ppm and 157.68–160.2 ppm assign them to the C(2), C(6), C(g) and C(h), C(i) carbon atoms respectively. The solution structure and stereoretentive transformation in each step have been established from n.m.r. results. Cyclic voltammograme show a Ru(III)/Ru(II) couple at 1.0–1.1 V versus SCE along with three successive ligand reductions.

Synthesis and Characterization of a Novel Heteroditopic Macrocyclic System – Monometallic Nickel(II) and Uranyl Complexes and Their Corresponding Heterobimetallic Carbonylrhodium(I) Complexes

AbstractA novel heteroditopic macrocyclic ligand system for selective coordination of two different transition metal ions has been obtained in the form of monometallic salen complexes of NiII (LNi, 1) and uranyl (LUO2, 2). The system is characterized by the presence of a dianionic, tetradentate salen donor system (N2O2) derived from cis‐1,2‐diaminocyclohexane and of a neutral, tridentate 2,6‐bis(alkylthiomethyl)pyridine group (NS2). The two binding sites are connected by two oxyethyl chains. The synthetic procedure involves the coupling of the disodium salt of 2,6‐bis(mercaptomethyl)pyridine with two equivalents of 3‐(2‐bromoethoxy)‐2‐(2‐propenyloxy)benzaldehyde. Removal of the protecting allyl groups from the reaction product (I) by palladium catalysis yields the ligand synthon 2,6‐bis[2‐(3‐formyl‐2‐hydroxyphenyl)oxyethyl]thiomethylpyridine (II). The monometallic macrocyclic complexes 1 and 2, obtained by metal‐templated synthesis from cis‐1,2‐diaminocyclohexane, ligson II, and the corresponding NiII or uranyl acetate salts, respectively, in the presence of barium bis(trifluoroacetate), have been fully characterized by spectroscopic techniques in solution and by X‐ray diffraction analyses in the solid state. Both complexes react readily at room temperature with [Rh(CO)2Cl]2 in methanol to form the bimetallic cationic carbonyl complexes [LNiIIRh(CO)]PF6 (3) and [LUO2Rh(CO)]PF6 (4) upon addition of NH4PF6. Two conformers of complex 3 are observed in solution by IR and NMR spectroscopy, in a 5:1 ratio in [D2]dichloromethane, which exhibit a fluxional behavior and are shown to interconvert above room temperature in [D3]acetonitrile. The carbonylrhodium group in the bimetallic systems reacts further with methyl iodide in dichloromethane solution to form oxidative‐addition products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

The synthesis, spectroscopic properties and electrochemistry of (8-quinolinolato)-bis-{1-alkyl-2- (arylazoimidazole)}ruthenium(ii) hexafluorophosphate: single crystal X-ray structure of [ru(q)(meaaime)2](PF6)·CH2Cl2 [Q = 8-quinolinolate, meaaime = 1-methyl-2-( p-tolylazoimidazole)

The reaction of [Ru(OH2)2(RaaiR′)2]2+ [RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R–C6H4–N=N–C3H2–NN(1)–R′, R=H (1), Me (2), Cl (3); R′ = Me (a), Et (b), CH2Ph (c)] with 8-quinolinol (HQ) in acetone solution followed by the addition of NH4PF6 afforded violet, mixed ligand complexes of composition [Ru(Q)(RaaiR′)2](PF6). The structure of [Ru(Q)(MeaaiMe)2](PF6) (2a) has been confirmed by X-ray diffraction studies. Solution electronic spectra exhibit a strong MLCT band at 560–580 nm in MeCN. Cyclic voltammogrames show a Ru(III)/Ru(II) couple at 1.0–1.1 V versus SCE along with three successive ligand reductions. The electronic properties are correlated with EHMO results.

Vinylidene, Vinyl, and Carbene Ruthenium Complexes with Chelating Diphosphanes as Ligands

The ruthenium vinylidenes [RuCl2(=C=CHR)(PR′3)2] (1, 2) react with 1,2-C2H4(PCy2)2 (3) to give the chelate complexes [RuCl2(=C=CHR)(κ2-3)] (4, 5) by displacement of the two monodentate phosphane ligands. In contrast, the reaction of the hydrido compound [RuHCl(=C=CH2)(PCy3)2] (6) with excess 3 proceeds by migration of the hydride to the Cα carbon atom of the vinylidene unit and affords the six-coordinate vinyl complex trans-[RuCl(CH=CH2)(κ2-3)2] (7). Protonation of 7, followed by addition of NH4PF6, yields the cationic ruthenium carbene trans-[RuCl(=CHCH3)(κ2-3)2]PF6 (8), together with small quantities of the hydrido compound [RuH(κ2-3)2]PF6 (9). The Grubbs catalyst [RuCl2(=CHPh)(PCy3)2] (10) reacts with both 3 and [Fe(η5-C5H4PPh2)2] (11), also by ligand substitution, to give the corresponding chelate complexes [RuCl2(=CHPh)(κ2-3)] (12) and [RuCl2(=CHPh)(κ2-11)] (13); the latter has been characterized by X-ray crystal structure analysis.

Chelation Processes to an Oxorhenium(V) Center by N,N,N,O-Tetradentate and N,N,O-Tridentate Ligands As Verified by Structural and Mechanistic Studies of Intermediate Species

The reaction of [ReO(OEt)Cl2(PPh3)2] with N-(2-pyridylmethyl)-2-aminoethanol (mpenOH) afforded a mixture of ReV−oxo complexes, from which the dichloro complex [ReOCl2(mpenO-N,N‘,O)] (1) and the chlorotriphenylphosphine complex [ReOCl(PPh3)(mpenO-N,N‘,O)]PF6 (2) were isolated by addition of NH4PF6. Similarly, [ReO(OEt)Cl2(PPh3)2] reacted with N,N-bis(2-pyridylmethyl)-2-aminoethanol (bpenOH) to give the dichloro complex [ReOCl2(bpenO-N,N‘,O)] (3) and the monochloro complex [ReOCl(bpenO-N,N‘,N‘‘,O)]PF6 (4). When ethylene glycol (H2eg) was added to the mixture of [ReO(OEt)Cl2(PPh3)2] and bpenOH, [ReO(eg)(bpenOH-N,N‘,N‘‘)]ReO4 (5) was obtained. These five newly prepared complexes were structurally characterized. A mechanistic insight into the stepwise complex formation reaction of [ReO(OEt)Cl2(PPh3)2] with pyridylmethylamine derivatives (mpenOH and bpenOH) is discussed. Crystal data: [ReOCl2(mpenO)] (1), monoclinic, space group P21/c, a = 8.632(1) Å, b = 9.288(1) Å, c = 14.802(1) Å, β = 100.627(9)°, Z = 4; [ReOCl(PPh3)(mpenO)](PF6)·0.5CH3CN (2·0.5CH3CN), monoclinic, space group P21/a, a = 19.758(6) Å, b = 9.463(3) Å, c = 16.297(4) Å, β = 93.40(2)°, Z = 4; [ReOCl2(bpenO)] (3), monoclinic, space group P21, a = 6.577(1) Å, b = 13.269(2) Å, c = 9.686(2) Å, β = 105.00(2)°, Z = 2; [ReOCl(bpenO)](PF6) (4), triclinic, space group P1̄, a = 6.766(1) Å, b = 14.538(2) Å, c = 19.373(3) Å, α = 91.57(1)°, β = 97.43(1)°, γ = 91.62(1)°, Z = 4; [ReO(eg)(bpenOH)](ReO4) (5), monoclinic, space group P21/n, a = 12.691(2) Å, b = 14.030(2) Å, c = 11.153(2) Å, β = 90.72(1)°, Z = 4.

Mono- and Dinuclear Carbonyl Complexes of (1,4,7-Trimethyl-1,4,7-triazacyclononane)rhodium(I): Facile Migration of a C(O)OMe Ligand at a Dinuclear Rh(μ-CO)2Rh Core

The reaction of 1,4,7-trimethyl-1,4,7-triazacyclononane (Cn*) with [{(CO)2Rh(μ-Cl)}2] in methanol at 0°C, followed by the addition of NH4PF6, results in the formation of the mononuclear carbonyl complex [Cn*Rh(μ-CO)2]PF6 ([1]PF6), the dinuclear carbonyl complex [Cn*Rh(μ-CO)3RhCn*](PF6)2 {[2](PF6)2} and the dinuclear methoxycarbonyl complex [Cn*Rh(C(O)OMe)(μ-CO)2RhCn*]PF6 ([3]PF6). The reaction of [2](PF6)2 with NaOMe results in formation of [3]PF6 by the attack of the methoxide at a bridging carbonyl. Treatment of [3]PF6 with NH4PF6 regenerates [2](PF6)2, thus showing that the methoxylation of [2](PF6)2 is reversible. The structures of [1]PF6, [2](PF6)2 and [3]PF6 have been determined by single-crystal X-ray diffraction. For [3]PF6 an unprecendented facile, reversible, migration of the C(O)OMe ligand between the two rhodium centres of the Rh(μ-CO)2Rh core is observed.

Synthesis of binuclear platinum metal N4O2-compartmental complexes: the structures of the protonated metal-free macrocycle [LH4](PF6)2·MeNO2and of [Pd2(L)](BF4)2·2MeNO2

Reaction of [LH4](PF6)2, formed by condensation of 1,3-diaminopropane and 2,6-diformyl-4-methylphenol in the presence of HBr followed by addition of NH4PF6, with platinum metal salts in the presence of base affords [M2(L)]2+(M = Pd, Pt) and [M2Cl4(L)](M = Rh); the structure of [LH4](PF6)2·MeNO2 shows a folded conformation incorporating both inter- and intra-molecular π–π interactions between phenyl rings; in contrast, the structure of [Pd2(L)](BF4)2·2MeNO2 shows the binucleating macrocycle to be planar with intermolecular π-ring stacking.

ChemInform Abstract: Synthesis and Single‐Crystal X‐Ray Structure Determination of trans‐(RhCl2(tmc))PF6 (tmc: 1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane).

AbstractThe title complex (I) is synthesized by equimolar reaction of RhCl3·3 H2O with the macrocycle in refluxing methanol followed by addition of NH4PF6.

ChemInform Abstract: Hydrido Platinum Metal Macrocyclic Complexes: The Synthesis and Single‐Crystal X‐Ray Structure of cis‐(IrCl(H)L1)PF6 (L1: 7‐Methyl‐3,7,11,17‐tetraazabicyclo(11.3.1)heptadeca‐1(17),13,15‐triene).

AbstractThe title complex (I) is obtained by 1:1 molar reaction of IrCl3·3H2O and the macrocycle in refluxing aqueous ethanol followed by addition of NH4PF6.

ChemInform Abstract: Spectroscopic, Electrochemical, and Kinetic Characterization of New Ruthenium(II) Tris‐Chelates Containing Five‐Membered Heterocyclic Moieties.

AbstractRu(II) chelates (I) are prepared by reaction of RuCl3·3 H2O with an excess of the NN‐ligand in refluxing ethylene glycol or ethanol followed by addition of NH4PF6.

ChemInform Abstract: Stability of d3 Diimine Complexes: Molybdenum(III) vs. Chromium(III).

AbstractThe octahedral tris(bipyridine)‐Mo(III) complex (I) is obtained by reaction of (NH4)2(MoCl5(OH2)) with three equiv. of 2,2'‐bipyridine in MeOH at room temp. followed by addition of NH4PF6 (yield given in mg).

ChemInform Abstract: Preparation, Characterization, and Oxidation Chemistry of (Rh2(dimen)2(dppm)2)(PF6)2 (dimen: 1,8‐Diisocyanomenthane; dppm: Bis(diphenylphosphino)methane). Electrochemical Generation of a Stable d7‐d8 Radical.

AbstractThe addition of stoichiometric amounts of 1,8‐diisocyanomenthane to (RhCl(CO)(Ph2P‐CH2‐PPh2))2 in MeOH leads to the isolation of a crystalline product (I) upon addition of NH4PF6.