Organic Cation Salts Research Articles

Toward Greater DNA Stability by Leveraging the Proton-Donating Ability of Protic Ionic Liquids.

Deoxyribonucleic acid (DNA) stability is a prerequisite in many applications, ranging from DNA-based vaccines and data storage to gene therapy. However, the strategies to enhance DNA stability are limited, and the underlying mechanisms are poorly understood. Ionic liquids (ILs), molten salts of organic cations and organic/inorganic anions, are showing tremendous prospects in myriads of applications. With a judicious choice of constituent ions, the protic nature of ILs can be tuned. In this work, we investigate the relative stability of full-length genomic DNA in aqueous IL solutions of increasing protic nature. Our experimental measurements show that the protic ionic liquids (PILs) enhance the DNA melting temperature significantly while unaltering its native B-conformation. Molecular dynamics simulations and quantum mechanical calculation results suggest that the intramolecular Watson-Crick H-bonding in DNA remains unaffected and, in addition, the PILs induce stronger H-bonding networks in solution through their ability to make multiple intermolecular H-bonds with the nucleobases and among its constituent ions, thus aiding greater DNA stability. The detailed understanding obtained from this study could bring about the much-awaited breakthrough in improved DNA stability for its sustained use in the aforesaid applications!

Leveraging Dion–Jacobson Interface Hierarchies for Defect Alleviation in High-Efficiency and Durable Perovskite Solar Cells

The noteworthy stability of Dion–Jacobson (DJ) phase two-dimensional perovskites marks them as potential contenders for use in optoelectronic applications. Nonetheless, their proliferation is considerably stymied by the constrained charge transport properties inherent to them. This bottleneck is adeptly navigated by deploying 2D-DJ perovskite top layers, seamlessly integrated on 3D perovskite films. We unveil a novel organic cation salt, 4-(Aminomethyl)piperidine (4AMP), as a potent facilitator for treating perovskite photovoltaic films. By employing the annealing technique, we facilitated the in situ creation of a hybrid 2D/3D architecture. Contrasted with conventional 3D architectures, the delineated perovskite heterojunctions with a 2D/3D structure exhibit superior enhanced charge separation, and mitigate photovoltaic losses by proficiently passivating intrinsic defects. The size-graded perovskite 2D/3D structure engineered herein significantly elevates the charge transfer performance, concurrently attenuating the excess lead iodide induced by bulk defects. This precise method resulted in a significant increase in Power Conversion Efficiency, reaching 23.08%, along with an open-circuit voltage (Voc) of 1.17 V. Remarkably, the unpackaged modified device robustly retains 92% of its initial PCE post a 3000 h sojourn under ambient conditions. This discourse propounds a novel paradigm for constructing stable planar PSC 2D/3D heterojunctions, thereby enriching the blueprint for advanced perovskite-based photovoltaic systems.

Towards low-temperature processing of efficient γ-CsPbI3 perovskite solar cells.

Inorganic cesium lead iodide (CsPbI3) perovskite solar cells (PSCs) have attracted enormous attention due to their excellent thermal stability and optical bandgap (∼1.73 eV), well-suited for tandem device applications. However, achieving high-performance photovoltaic devices processed at low temperatures is still challenging. Here we reported a new method for the fabrication of high-efficiency and stable γ-CsPbI3 PSCs at lower temperatures than was previously possible by introducing the long-chain organic cation salt ethane-1,2-diammonium iodide (EDAI2) and regulating the content of lead acetate (Pb(OAc)2) in the perovskite precursor solution. We find that EDAI2 acts as an intermediate that can promote the formation of γ-CsPbI3, while excess Pb(OAc)2 can further stabilize the γ-phase of CsPbI3 perovskite. Consequently, improved crystallinity and morphology and reduced carrier recombination are observed in the CsPbI3 films fabricated by the new method. By optimizing the hole transport layer of CsPbI3 inverted architecture solar cells, we demonstrate efficiencies of up to 16.6%, surpassing previous reports examining γ-CsPbI3 in inverted PSCs. Notably, the encapsulated solar cells maintain 97% of their initial efficiency at room temperature and under dim light for 25 days, demonstrating the synergistic effect of EDAI2 and Pb(OAc)2 in stabilizing γ-CsPbI3 PSCs.

Novel co-crystals with π-hole interactions between iodide anions and quinoid rings involving charge transfer

Six novel co-crystals of tetrabromoquinone with iodide salts of organic cations displaying short contacts between iodide anions and the quinoid rings have been structurally characterised.

Homoleptic trimethylsilylchalcogenolato zincates [Zn(ESiMe3)3]- and stannanides [Sn(ESiMe3)3]- (E = S, Se): precursors in solution-based low-temperature binary metal chalcogenide and Cu2ZnSnS4 (CZTS) synthesis.

Organic cation salts with homoleptic zincate and stannanide anions, Ph4P [Zn(ESiMe3)3] (E = S (1a), Se (1b)) and Cat [Sn(ESiMe3)3] (Cat = Ph4P+ (E = S (2a-Ph4P); Cat = PPN+ (E = S 2a-Ph4P, Se (2a)) are presented and structurally characterized. Efforts to isolate neutral thermally metastable stannane precursors [Sn(ESiMe3)4] (E = S (3), Se(4)) are reported as well. The thermal decomposition of the presented precursors to yield binary sulfides and selenides of zinc and tin is investigated. Furthermore, the potential of using the title anions as precursors in solution-based low-temperature synthesis of Cu2ZnSnS4 (CZTS) by coprecipitation with [Cu(tmtu)3]PF6 and subsequent annealing is discussed.

Novel screening method for the crystallization of salts of organic cations

Novel screening method for the crystallization of salts of organic cations

A high throughput screening method for the nano-crystallization of salts of organic cations.

The generation of solid salts of organic molecules is important to the chemical and pharmaceutical industry. Commonly used salt screening methods consume a lot of resources. We employed a combination of ion exchange screening and vapour diffusion for crystallization. This technique is semi-automatic and requires just nanoliters of the solution of the analyte to be crystallized. This high throughput screening yielded single crystals of sufficient size and quality for single-crystal X-ray structure determination using an in-house X-ray diffractometer. The broad scope of our method has been shown by challenging it with 7 very different organic cations, whose aqueous solubilities vary by a factor of almost 1000. At least one crystal structure for 6 out of 7 tested cations was determined; 4 out of the successful 6 ones had never been crystallized before. Our method is extremely attractive for high throughput salt screening, especially for active pharmaceutical ingredients (APIs), as about 40% of all APIs are cationic salts. Additionally, our screening is a new and very promising procedure for the crystallization of salts of organic cations.

Inorganic Anions Regulate the Phase Transition in Two Organic Cation Salts Containing [(4-Nitroanilinium)(18-crown-6)]+ Supramolecules

Inorganic Anions Regulate the Phase Transition in Two Organic Cation Salts Containing [(4-Nitroanilinium)(18-crown-6)]+ Supramolecules

Inorganic vs Organic Cation Ionic Liquids and Their Solutions with Alkali Metal Containing Ionic Liquids

The burgeoning field of ionic liquids (in the current sense of low-melting liquids (Tm < 100°C) consisting only of ions), has been dominated by liquids containing organic molecular cations. Although a few cases of all-inorganic ionic liquids are known, the field is relatively unexplored. As in the case of the organic cation salts, the inorganic ionic liquids can have aprotic, protic, and solvate cases, and can also be mixed with low melting alkali salts to give mixed alkali-molecular inorganic ionic liquid systems. Here we explore the interesting properties of (i) a low-melting alkali bromoaluminate, NaAl2Br7, which exhibits huge alkali cation decoupling in the crystalline state (such that there is very little change in conductivity on fusion) and (ii) its mixture with the low-melting inorganic ionic liquid [PBr4+][Al2Br7−]. The structures and ionicities are confirmed by Walden plots and by 31P and 27Al NMR spectroscopy.

Simple access to ionic liquids and organic salts containing the phosphaethynolate (PCO−) and Zintl (Sb113−) anions

Herein we report the synthesis of the first ionic liquids with the highly reactive and synthetically valuable phosphaethynolate (PCO(-)) anion. They are simply synthesised by the reaction of organic methylcarbonate salts with P(SiMe3)3. The products are obtained in near to quantitative yields and they are highly viscous liquids at room temperature or have low melting points for symmetric cations. Moreover, extending this synthetic strategy towards Sb(SiMe3)3 we discovered a simple synthesis for [P(nBu)3Me](+)3[Sb11](3-), the first organic cation salt comprising the Zintl-anion [Sb11](3-).

Inorganic-Organic Hybrid Ionic Liquid Electrolytes for Na Secondary Batteries

Sodium secondary batteries are attracting more and more attraction as energy storage devices for stationary use and electric vehicles due to high abundance and low cost of sodium resources as well as the low redox potential of Na+/Na. Ionic liquid electrolytes are attractive to improve the safety issues of sodium secondary batteries, owing to their unique properties such as low flammability and low vapor pressure [1-3]. Our recent works suggest FSA- (FSA- = bis(fluorosulfonyl)amide anion) based ionic liquids, such as Na[FSA]-K[FSA] and Na[FSA]-[C3C1pyrr][FSA] (C3C1pyrr+ = N-propyl-N-methylpyrrolidinium cation) systems, exhibit good physical and electrochemical properties as electrolytes for Na secondary batteries [4-6]. This study will present a new series of inorganic-organic hybrid ionic liquids as electrolytes for Na secondary batteries. Four FSA salts of organic cations, N6111 + (hexyltrimethylammonium), N4422 + (dibutyldimethylammonium), AS[4.5]+ (azoniaspiro[4.5]nonane), and C2C1im+ (1-ethyl-3-methylimidazolium), are mixed with Na[FSA]. In all the cases, a wide liquid temperature range around room temperature was observed in a certain x(Na[FSA]) range. Ionic conductivity and viscosity increase and decrease with decreasing x(Na[FSA]), respectively. The highest ionic conductivity was observed for the Na[FSA]-[C2C1im][FSA] system. Electrochemical windows are around 5 V and Na metal deposition and dissolution are observed at the cathode limit. The efficiency of Na metal deposition and dissolution is improved by increasing temperature due to suppression of dendritic Na metal deposition.[1] L.G. Chagas, D. Buchholz, L.M. Wu, B. Vortmann, S. Passerini, J. Power Sources, 247 (2014) 377-383.[2] S.A.M. Noor, P.C. Howlett, D.R. MacFarlane, M. Forsyth, Electrochim. Acta, 114 (2013) 766-771.[3] D. Monti, E. Jonsson, M.R. Palacin, P. Johansson, J. Power Sources, 245 (2014) 630-636.[4] C. Ding, T. Nohira, K. Kuroda, R. Hagiwara, A. Fukunaga, S. Sakai, K. Nitta, S. Inazawa, J. Power Sources, 238 (2013) 296-300.[5] T. Yamamoto, T. Nohira, R. Hagiwara, A. Fukunaga, S. Sakai, K. Nitta, S. Inazawa, J. Power Sources, 217 (2012) 479-484.[6] C.Y. Chen, K. Matsumoto, T. Nohira, R. Hagiwara, A. Fukunaga, S. Sakai, K. Nitta, S. Inazawa, J. Power Sources, 237 (2013) 52-57.

Coordination compounds of electron-deficient boron cluster anions B n H n 2− (n = 6, 10, 12)

This survey concerns the coordination ability of B n H 2− (n = 6, 10, 12) boron cluster anions and their derivatives in complex formation. Boron cluster anions form four types of compounds: salts of organic cations and alkali-metal cations, including Cat2B n H n , where specific interactions can be observed between a cation Cat and a boron cluster anion; salts of protonated anions CatB6H7 and CatB10H11, analogues of Cat[MB n H n ] complexes, where an extra hydrogen atom appears bound with the BBB face of a boron polyhedron and performs as a hard acceptor; metal complexes with outer-sphere boron cluster anions where specific ligand-ligand interactions may be observed between a boron cluster anion and an inner-sphere ligand; and true metal complexes with boron cluster anions that enter the inner coordination sphere. The last case characterizes closo-hydroborate anions as polydentate ligands whose denticity can vary widely under the effect of substituents or other ligands in the complex.

Crystal Synthesis of Organic−Inorganic Hybrid Salts Based on Tetrachloroplatinate and -palladate Salts of Organic Cations: Formation of Linear, Two-, and Three-Dimensional NH···Cl Hydrogen Bond Networks

A series of new crystal structures of salts containing [PtCl4]2- or [PdCl4]2- with organic cations containing pyridinium and piperidinium groups have been prepared: [4,4‘-H2bpe][PtCl4] (2), [4,4‘-H2bpethane][PtCl4] (3), [HNC5H4CO2H-4]2[PtCl4] (6a), [HNC5H4CONH2-3]2[PtCl4] (8), [H2NC5H9CO2H-4]2[PtCl4] (9), [H2NC5H9CO2H-3]2[PtCl4] (10), [H2NC5H9CO2H-4]Cl (11), [HNC5H4CO2H-4]Cl (12), [4,4‘-H2bpe][PdCl4] (13), [4,4‘-H2bipip][PdCl4] (14a, 14b, 14c), [piperazinium][PdCl4]·2H2O (15), and [HNC5H4CO2H-4]2[PdCl4]·2H2O (16). The molecular recognition motifs formed in these and related structures are identified and discussed. The robustness of these supramolecular synthons and their applicability in synthetic crystallography are analyzed. Cases of structural mimicry of a molecule by a supramolecular dication (1 and 6a), isomorphism (2 and 3; 4 and 14a; 6 and 16), polymorphism (14a−c), and “latent” polymorphism (2 and 13) are identified.

Optical Properties of Solid Pseudoisocyanine Films Doped with Cluster Derivatives of Boron Hydrides

The formation and optical properties of J aggregates of pseudoisocyanine iodide in solid films in the presence of cluster anionic derivatives of boron hydrides and carboranes (B10H102-, B12H122-, B20H182-, [NiIV(1,2-B9C2H11)2]0, 1,2-B9C2H12-, [Co(1,2-B9C2H11)2]-, [Ni(1,2-B9C2H11)2]-, B10H8I22-, [Sn(1,2-B9C2H11)]0) are studied. It is shown that the addition of anions B10H102- or B10H8I22- leads to an efficient formation of stable J aggregates. The addition of carborane complex of nickel [NiIV (1,2-B9C2H11)2]0 also leads to the formation of J aggregates, although less stable ones. Carborane complex of tin [SnII(1,2-B9C2H11)]0 facilitates the formation of a monomeric form of the dye. The remaining compounds yield no distinct pattern of formation of a certain monomeric or J-aggregated film structure. With the aid of the semiempirical AM1 method, the charge distributions in the cation of the dye and anionic derivatives of the boron hydrides are calculated. It is supposed that the bipolar distribution of a negative charge in the B10H102- anion facilitates the formation of a J aggregate. By addition of salts of organic cations to a film of pseudoisocyanine-closo-hydrodecaborate (PCG), J aggregates with a narrow width of the J peak are obtained. The thermal decay of J aggregates in these films is studied. On the basis of the data obtained (the presence of an isosbestic point upon thermal decomposition of J aggregates and their reaggregation; the narrowing and increasing of the J absorption peak, as well as increasing of luminescence, upon dilution of a J-aggregated PCG film with organic cations; and the bipolar character of the electrostatic interaction of the B10H102- anion with the dye), it is assumed that the J peak of pseudoisocyanine in the films studied corresponds to the absorption of a dimeric form of the dye.

Sorption of Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) Compounds by Hectorite Clays Exchanged with Aromatic Organic Cations

AbstractAdsorptive-type organoclays, where hydrocarbons adsorb directly to the siloxane surfaces, were studied to find new organic cations and to determine the parameters that produce effective sorbents. Organoclays were prepared from hectorite by cation exchange with small, aromatic organic cation salt solutions. Trimefhylphenylammonium (TMPA) chloride was obtained and iodide salts of commercially-unavailable aromatic cations were synthesized and used to prepare organoclays. An aqueous mixture of benzene, toluene, ethylbenzene, and xylenes (BTEX) consistent with the composition of unleaded gasoline was used in sorption isotherms to compare the sorptive properties of the organoclays. Only the TMPA, methylphenylpyridinium (MPPyr), and trimethylammonium indan (Indan) organoclays were effective BTEX sorbents. Organoclays prepared from methylpyridinium (MPyr), trimethylammonium biphenyl (Biphenyl), and trimethylammonium fluorene (Fluorene) were poor sorbents. The MPPyr and TMPA organoclays preferentially sorbed ethylbenzene, whereas the Indan organoclay preferentially sorbed benzene and toluene. Langmuir-type sorption isotherms for the TMPA, MPPyr, and Indan organoclays implied surface adsorption, whereas linear isotherms suggested that partitioning was the sorptive mechanism for the MPyr, Biphenyl, and Fluorene organoclays. Water hydrating the small MPyr cation and the larger bulk of the Biphenyl and Fluorene cations may have blocked BTEX access to the interlayer siloxane surfaces. Although the rather bulky MPPyr and Indan cations produced effective organoclays, compact size and low hydration are organic cation properties that typically yield effective adsorptive-type organoclays.

Toward Crystal Engineering of Organic Porous Solids: Diammine Salts of Trimesic Acid1

We report the synthesis and X-ray crystallographic characterization of three new dibasic organic cation salts of 1,3,5-benzenetricarboxylic acid, trimesic acid. The focus of the study concerns crystal engineering of organic solids with predictable but fine-tuneable porosity. All three salts self-assemble into 2-D grids via interionic hydrogen bonding. Full details of single crystal X-ray diffraction studies of the salts are reported: (1) N,N,N′,N′-tetramethylethylenediammonium dihydrogentrimesate dihydrate, [HMe2NCH2CH2NMe2H]2[1-CO2-3,5(CO2H)2C6H3]·2H2O, a = 12.583(3), b = 15.1177(13), c = 15.407(3), β = 113.466(20), P21/c, d calc(Mg/m3) = 1.42, Z = 4, 3515 unique reflns., R f = 0.061, R w = 0.055; (2) N,N,N′,N′-tetraethylethylenediammonium dihydrogentrimesate, [HEt2NCH2CH2NEt2H]2[1-CO2-3,5(CO2H)2C6H3], a = 6.6196(18), b = 9.243(2), c = 12.360(4), α = 75.16(4), β = 75.88(5), γ = 84.297(22), P1, d calc(Mg/m3) = 1.39, Z = 1, 1844 unique reflns., R f = 0.056, R w = 0.050; (3) N,N,N′,N′-tetramethylethylenediammonium hydrogentrimesate, [HMe2NCH2CH2NMe2H][1,3-(CO2)2-5-(CO2H)C6H3], a = 8.636(4), b = 21.6877(17), c = 9.436(5), β = 114.49(6), P21/c, d calc(Mg/m3) = 1.35, Z = 4, 2820 unique reflns., R f = 0.050, R w = 0.054.

The Origin of Bulk Polarity in Hydrogensulfate Salts

Abstract The crystal packing motifs exhibited by hydrogensulfate salts, including 10 new organic cation salts, are analyzed in the context of understanding the criteria that control bulk polarity in the absence of chiral moieties. Fortyfive hydrogensulfate salts were analyzed, 27 crystallize via head-to-tail strand motifs that are conducive to the presence of bulk polarity, 16 crystallize via packing of dimer motifs and 2 exhibit cocrystallization of both strand and dimer motifs. The majority of the strand motifs randomly aggregate via one of the expected crystallographic operations: translation, glide or screw. However, only 8 compounds crystallize in non-centrosymmetric space groups. The most desirable aggregate from the perspective of maximizing bulk polarity, the translation aggregate, was observed in 9 compounds. We discuss our observations in the broader context with particular emphasis on the development of strategies for crystal engineering of polar solids.

Synthesis, Reactivity, and Structural Characterization of the Nonclassical [MTe(7)](n)()(-) Anions (M = Ag, Au, n = 3; M = Hg, n = 2).

Several tellurometalates of the general formula [MTe(7)](n)()(-) (n = 2, 3) have been isolated as salts of organic cations by reaction of suitable metal sources with polytelluride solutions in DMF. The [HgTe(7)](2)(-) anion has the same structure in both the NEt(4)(+) and the PPh(4)(+) salts except for a minor change in the ligand conformation. The [AgTe(7)](3)(-) and [HgTe(7)](2)(-) anions contain metal atoms coordinated in trigonal-planar fashion to eta(3)-Te(7)(4)(-) ligands. The central Te atom of an eta(3)-Te(7)(4)(-) ligand is coordinated to the metal atom and to two Te atoms in a "T"-shaped geometry consistent with a hypervalent 10 e(-) center. The planar [AuTe(7)](3)(-) anion may best be described as possessing a square-planar Au(III) atom coordinated to an eta(3)-Te(5)(4)(-) ligand and to an eta(1)-Te(2)(2)(-) ligand. The reaction of [NEt(4)](n)()[MTe(7)] (M = Hg, n = 2; M = Au, n = 3) with the activated acetylene dimethyl acetylenedicarboxylate (DMAD) has yielded the products [NEt(4)](n)()[M(Te(2)C(2)(COOCH(3))(2))(2)] (M = Hg, n = 2; M = Au, n = 1). The metal atoms are coordinated to two Te(COOCH(3))C=C(COOCH(3))Te(2)(-) ligands, for M = Hg in a distorted tetrahedral fashion and for M = Au in a square-planar fashion.

Organic cation salts of the tetrafluoroaluminate anion. Yes, it does exist, and yes, it is tetrahedral

Organic cation salts of the tetrafluoroaluminate anion. Yes, it does exist, and yes, it is tetrahedral

The permeability of the cGMP-activated channel to organic cations in retinal rods of the tiger salamander.

1. The permeability of the channel activated by guanosine 3',5'-cyclic monophosphate (cGMP) to many organic monovalent cations was determined by recording macroscopic currents in excised inside-out patches of plasma membrane from isolated retinal rod outer segments of the tiger salamander. 2. Current-voltage relations were measured when the NaCl of the bathing medium was replaced by salts of organic cations. Permeability ratios relative to Na+ ions were calculated with the Goldman-Hodgkin-Katz potential equation from the measured changes of reversal potentials. 3. Hydroxylammonium+, hydrazinium+ and methylammonium+, which are molecules of very similar shape and size, permeate the channel with very different permeability ratios: 5.92, 1.99 and 0.60 respectively. 4. Methylated and ethylated ammonium+ compounds were investigated. It was found that, not only methylammonium+, but also dimethylammonium+ and ethylammonium+ were permeant with permeability ratios of 0.6, 0.14 and 0.16 respectively. Trimethylammonium+, tetramethylammonium+, diethylammonium+, triethylammonium+, and tetraethylammonium+ were not permeant. 5. Guanidinium+ and its derivatives formamidinium+, aminoguanidinium+, acetamidinium+ and methylguanidinium+ were all permeant with permeability ratios 1.12, 1.00, 0.63, 0.36 and 0.33 respectively. 6. The cGMP-activated channel was found to be permeable to at least thirteen organic cations. Molecular models of the permeant cations indicate that the cross-section of the narrowest part of the pore must be at least as large as a rectangle of 0.38 x 0.5 nm dimensions.