Stacks Of Cations Research Articles

Crystal structure of cariprazine dihydrochloride, C21H34Cl2N4OCl2

The crystal structure of cariprazine dihydrochloride has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Cariprazine dihydrochloride crystallizes in space group P21/n (#14) with a = 27.26430(14), b = 7.29241(1), c = 12.80879(4) Å, β = 99.5963(2)°, V = 2511.038(8) Å3, and Z = 4 at 295 K. The crystal structure consists of layers of cations parallel to the bc-plane. The cations stack along the b-axis. Each H atom on the two protonated N atoms participates in a discrete N–H⋯Cl hydrogen bond. One Cl anion acts as an acceptor in two of these bonds, while the other Cl is an acceptor in only one bond. The result is to link the cations and anions into columns parallel to the b-axis. The powder pattern has been submitted to the ICDD for inclusion in the Powder Diffraction File™ (PDF®).

Prediction of Novel Trigonal Chloride Superionic Conductors as Promising Solid Electrolytes for All-Solid-State Lithium Batteries.

Recently emerging lithium ternary chlorides have attracted increasing attention for solid-state electrolytes (SSEs) due to their favorable combination between ionic conductivity and electrochemical stability. However, a noticeable discrepancy in Li-ion conductivity persists between chloride SSEs and organic liquid electrolytes, underscoring the need for designing novel chloride SSEs with enhanced Li-ion conductivity. Herein, an intriguing trigonal structure (i.e., Li3SmCl6 with space group P3112) is identified using the global structure searching method in conjunction with first-principles calculations, and its potential for SSEs is systematically evaluated. Importantly, the structure of Li3SmCl6 exhibits a high ionic conductivity of 15.46 mS cm-1 at room temperature due to the 3D lithium percolation framework distinct from previous proposals, associated with the unique in-plane cation ordering and stacking sequences. Furthermore, it is unveiled that Li3SmCl6 possesses a wide electrochemical window of 0.73-4.30V vs Li+/Li and excellent chemical interface stability with high-voltage cathodes. Several other Li3MCl6 (M = Er, and In) materials with isomorphic structures to Li3SmCl6 are also found to be potential chloride SSEs, suggesting the broader applicability of this structure. This work reveals a new class of ternary chloride SSEs and sheds light on strategy for structure searching in the design of high-performance SSEs.

Influence of Interlayer Cation Ordering on Na Transport in P2-Type Na0.67-xLiy Ni0.33-zMn0.67+zO2 for Sodium-Ion Batteries.

P2-type Na2/3Ni1/3Mn2/3O2 (PNNMO) has been extensively studied because of its desirable electrochemical properties as a positive electrode for sodium-ion batteries. PNNMO exhibits intralayer transition-metal ordering of Ni and Mn and intralayer Na+/vacancy ordering. The Na+/vacancy ordering is often considered a major impediment to fast Na+ transport and can be affected by transition-metal ordering. We show by neutron/X-ray diffraction and density functional theory (DFT) calculations that Li doping (Na2/3Li0.05Ni1/3Mn2/3O2, LFN5) promotes ABC-type interplanar Ni/Mn ordering without disrupting the Na+/vacancy ordering and creates low-energy Li-Mn-coordinated diffusion pathways. A structure model is developed to quantitatively identify both the intralayer cation mixing and interlayer cationic stacking fault densities. Quasielastic neutron scattering reveals that the Na+ diffusivity in LFN5 is enhanced by an order of magnitude over PNNMO, increasing its capacity at a high current. Na2/3Ni1/4Mn3/4O2 (NM13) lacks Na+/vacancy ordering but has diffusivity comparable to that of LFN5. However, NM13 has the smallest capacity at a high current. The high site energy of Mn-Mn-coordinated Na compared to that of Ni-Mn and higher density of Mn-Mn-coordinated Na+ sites in NM13 disrupts the connectivity of low-energy Ni-Mn-coordinated diffusion pathways. These results suggest that the interlayer ordering can be tuned through the control of composition, which has an equal or greater impact on Na+ diffusion than the Na+/vacancy ordering.

4-(1H-2,3-Dihydronaphtho-[1,8-de][1,3,2]di-aza-borinin-2-yl)-1-ethylpyridin-1-ium iodide monohydrate.

The cation of the title hydrated salt, C17H17BN3 +·I-·H2O, is a di-aza-borinane featuring substitution at the 1, 2, and 3 positions in the nitro-gen-boron six-membered heterocycle. The cation is approximately planar with a dihedral angle between the pyridyl ring and the di-aza-borinane ring system of 5.40 (5)°. In the crystal, the cations stack along [100] in an alternating head-to-tail manner, while the iodide ion and water mol-ecule form one-dimensional hydrogen-bonded chains beside the cation stack. The cation stacks and I--water chains are crosslinked by N-H⋯I and N-H⋯O hydrogen bonds.

Synthesis, Crystal structure, weak interactions and Optical Properties of An Organic Charge-Transfer Compound―Benzyl 2-Aminopyridinium Picrate

In this work, a new organic charge-transfer compound, 1-benzyl 2-aminopyridinium picrate, [Bz-2-NH2Py][PIC](1), was prepared and characterized by single crystal X-ray diffraction (SC-XRD), power X-ray diffraction (PXRD), FT-IR, 1HNMR and Raman spectroscopy. The title compound crystallizes in monoclinic system with space group P2(1)/c, and contains one [Bz-2-NH2Py]+ cation and one [PIC]− anion. The cations stack into a columnar structure through C–H···π interactions and the N-H∙∙∙O and C-H∙∙∙O hydrogen bonds between the anions and cations stabilize the crystal stacking of [Bz-2-NH2Py][PIC](1). The frontier molecular orbitals HOMO and LUMO were computed with DFT (using B3LYP/6-31Gþ(d, p) basis set) approach to understand the chemical reactivity and kinetic stability of the title compound. The geometrical parameters obtained from XRD experiment are good in agreement with the simulated values from single crystal structure. In addition, the organic material shows two main emission peaks about 390 and 469 nm upon excitation at 241 nm in solid state at room temperature. Hirshfeld surface analysis was performed to quantify the contributions of the different intermolecular interactions.

Ultralow thermal conductivity and thermally-deactivated electrical transport in a 1D silver array with alternating δ-bonds.

We report the synthesis of a (TMA)AgBr2 (TMA = tetramethylammonium) crystal, which comprises inorganic anionic chains of -(AgBr2)∝- stabilized by columnar stacks of organic TMA cations with a periodic arrangement of shorter and longer Ag(i)⋯Ag(i) bonds, even though all the Ag(i) ions are chemically equivalent. The presence of two chemically non-equivalent bridging Br ions is attributed to the primary cause of such an unusual arrangement, as clearly visualized in the charge density plot of (TMA)AgBr2 extracted from the theoretical calculations based on density functional theory. Remarkably, we identified from the orbital-projected density of states the existence of alternate δ-like bonding involving d xy orbitals of 4d10 Ag(i), which was attributed to the cause for ultralow thermal conductivity and thermally-deactivated electrical transport in (TMA)AgBr2. Barring the energetics, our observations on the existence of a δ-bond will shed new light in understanding the nature of metal-metal chemical bonding and its unprecedented implications.

Nanoarchitectonics and Molecular Docking of 4-(Dimethylamino)Pyridin-1-Ium 2-3 Methyl-4-Oxo-Pyri-Do[1,2-a]Pyrimidine-3-Carboxylate

A retro-Claisen reaction of 1-(4-oxo-4H-pyrido [1,2-a]pyrimidin-3-yl)butane-1,3-dione, 3, in the presence of potassium hydroxide and 4-dimethylamino-pyridine has been carried out, leading to 4-(dimethylamino)pyridin-1-ium 2-methyl-4-oxo-pyrido [1,2-a]pyrimidine-3-carboxylate 5. A plausible mechanism explaining the formation of the title compound has been proposed. A single-crystal X-ray diffraction analysis confirms the crystal structure of the isolated organic salt (5). In the crystal, the title compound adopts a layered structure where there are stacks of cations and anions formed by slipped π-stacking interactions. These stacks are linked by regions consisting of water molecules that are hydrogen-bonded together. DFT and Hirshfeld surface analysis supported the experimental results of the molecular geometry and the intercontacts between different units in the crystal. The druglikeness, ADMET properties, and predicted targets were investigated, and the observed results suggest that 5 may act as a carbonic anhydrase I inhibitor. The assumption is confirmed by docking 5 into the active binding site of carbonic anhydrase, which shows it to have good binding affinities and to form stable complexes with the active residues of carbonic anhydrase I.

Progress on lanthanide sesquioxide phase transition

The present work aims to bring an original approach to the understanding of the polymorphic transition of RE2O3 from the low-temperature polymorph to the higher-temperature polymorph: from the cubic C to the hexagonal A form or from the monoclinic C to the monoclinic B form, for which the transition temperatures depend intimately on the rare earth element. The view proposed here, focusing on the lanthanide sesquioxide series, from Nd2O3 to Dy2O3, includes crystallographic and energetic considerations, using both bulk and surface energy calculations. After a complete description of the polymorphic filiations based on A, B and C unit cells described on simplified RE cation stacking schemes, it will be shown that the growth of the crystallite size as a function of temperature explains the existence of such transitions for these sesquioxides.

Novel design of flow path spacers for reverse electrodialysis cell

AbstractReverse electrodialysis (RED) is one of the technologies used to harness ‘Blue Energy’, which is generated from the controlled separation of ions between salt water and fresh water through cation and anion exchange membranes (CEM/AEM) stack with end electrodes. The spacers present in between CEM and AEM allows the flow of salt and fresh water significantly affecting the fouling and concentration polarization in the RED cell. The present work focuses on improvement in flow path design, which may be used in place of mesh spacers in order to reduce pressure drop and enhance shear stress on the surface of the membrane to reduce concentration polarization. A three‐dimensional direct numerical simulation of the Navier–Stokes equation is conducted using Fluent 14.0 to analyze four different flow field designs, including serpentine, criss‐cross, rhombus, diamond, and standard mesh spacers. The simulation predicted closely the experimental data on pressure drop for the mesh spacers available in the literature. The present study points out that the diamond type flow field design, which combines characteristics of mesh spacers and flow field plates, gives lesser pressure drop per unit length with the increase in velocity within the same range of shear stress generated in mesh spacers. In other words, net power density of RED would improve with the use of diamond type spacer flow field with the decrease in concentration polarization loss and pumping power density.

The Liquid-Mediated Synthesis and Performance Evaluation of Li-Zr-F Composite for Ion-Conduction

Crystalline lithium fluoride (LiF) has been intensively pursued as potential alternative solid electrolytes (SEs) owing to its excellent chemical and electrochemical oxidation stability, and good deformability. However, due to its low ion conductivity, LiF is still challenging for practical SE applications. Herein, Li-Zr-F composite-based SE by liquid-mediated synthesis is proposed to be studied. methanol (CH<sub>3</sub>OH) was mainly evaluated as a liquid-mediated precursor for synthesizing Li-Zr-F composites under the stoichiometric proportion of LiF and ZrF4 (2:1 and 2:0.8) and a subsequent annealing process at 25°C/150°C, 50°C/150°C, and 70°C/150°C, respectively. X-ray diffraction results revealed that the Li-Zr-F composites could be crystallized in the three main types of phase formations, including Li<sub>2</sub>ZrF<sub>6</sub> ( ), Li<sub>2</sub>ZrF<sub>6</sub> ( ), and Li<sub>4</sub>ZrF<sub>8</sub> ( ) octahedron structures. In addition, the effect of cation stack sublattice synthesized by methanol mediator on the ion conduction of Li-Zr-F composites was investigated by using electrochemical impedance spectroscopy (EIS). Through the Zr<sup>4+</sup>-substitution, Li<sub>2</sub>ZrF<sub>6</sub> ( )-based SE exhibited the highest ion conduction which was increased to 2.40 × 10<sup>-8</sup> S/cm and 3.89 × 10<sup>-8</sup> S/cm under the stoichiometric proportion of LiF and ZrF<sub>4</sub> 2:0.8 at a dried temperature of 50°C/150°C with, respectively. A 0.21 eV activation energy ( ) was achieved for a battery with Li<sub>2</sub>ZrF<sub>6</sub> ( )-based SE. Meanwhile, LiF exhibited up to 0.78 eV leading to a low kinetic rate for ion diffusion. These results implied that Li<sub>2</sub>ZrF<sub>6 </sub>( )-based SE was successfully synthesized under the optimal condition of CH<sub>3</sub>OH-50°C/150°C which could improve the ion-conductivity of LiF.

Charge‐Segregated Stacking Structure with Anisotropic Electric Conductivity in NIR‐Absorbing and Emitting Positively Charged π‐Electronic Systems

AbstractSquarylium‐based π‐electronic cation with an augmented dipole was synthesized by methylation of zwitterionic squarylium. The cation formed various ion pairs in combination with anions, and the ion pairs exhibited distinct photophysical properties in the dispersed state, ascribed to the formation of J‐ and H‐aggregates. The ion pairs provided solid‐state assemblies based on cation stacking. It is noteworthy that complete segregation of cations and anions was observed in a pseudo‐polymorph of the ion pair with pentacyanocyclopentadienide as a π‐electronic anion. In the crystalline state, the ion pairs exhibited photophysical properties and electric conductivity derived from cation stacking. In particular, the charge‐segregated ion‐pairing assembly induces an electric conductive pathway along the stacking axis. The charge‐segregated mode and fascinating properties were derived from the reduced electrostatic repulsion between adjacent π‐electronic cations via dipole–dipole interactions.

Charge-Segregated Stacking Structure with Anisotropic Electric Conductivity in NIR-Absorbing and Emitting Positively Chargedπ-Electronic Systems.

Squarylium-based π-electronic cation with an augmented dipole was synthesized by methylation of zwitterionic squarylium. The cation formed various ion pairs in combination with anions, and the ion pairs exhibited distinct photophysical properties in the dispersed state, ascribed to the formation of J- and H-aggregates. The ion pairs provided solid-state assemblies based on cation stacking. It is noteworthy that complete segregation of cations and anions was observed in a pseudo-polymorph of the ion pair with pentacyanocyclopentadienide as a π-electronic anion. In the crystalline state, the ion pairs exhibited photophysical properties and electric conductivity derived from cation stacking. In particular, the charge-segregated ion-pairing assembly induces an electric conductive pathway along the stacking axis. The charge-segregated mode and fascinating properties were derived from the reduced electrostatic repulsion between adjacent π-electronic cations via dipole-dipole interactions.

Synthesis, Structure, and Magnetic Properties of an Fe36 Dimethylarsinate Cluster: The Largest "Ferric Wheel".

The synthesis and characterization of a high-nuclearity FeIII/O/arsinate cluster is reported within the salt [Fe36O12(OH)6(O2AsMe2)63(O2CH)3(H2O)6](NO3)12 (1). The compound was prepared from the reaction of Fe(NO3)3·9H2O, dimethylarsinic acid (Me2AsO2H), and triethylamine in a 1:2:4 molar ratio in acetonitrile. The Fe36 cation of 1 is an unprecedented structural type consisting of nine Fe4 butterfly units of two types, three {FeIII4(μ3-O)2} units A, and six {FeIII4(μ3-O)(μ3-OH)} units B, linked by multiple bridging Me2AsO2- groups into an Fe36 triangular wheel/loop with C3 crystallographic and D3 virtual symmetry that looks like a guitar plectrum. The unusual structure has been rationalized on the basis of the different curvatures of units A and B, the presence of intra-Fe36 hydrogen bonding, and the tendency of Me2AsO2- groups to favor μ3-bridging modes. The cations stack into supramolecular nanotubes parallel to the crystallographic c axis and contain badly disordered solvent and NO3- anions. The cation of 1 is the highest-nuclearity "ferric wheel" to date and also the highest-nuclearity Fe/O cluster of any structural type with a single contiguous Fe/O core. Variable-temperature direct-current magnetic susceptibility data and alternating-current in-phase magnetic susceptibility data indicate that the cation of 1 possesses an S = 0 ground state and dominant antiferromagnetic interactions. The Fe2 pairwise Ji,j couplings were estimated by the combined use of a magnetostructural correlation for high-nuclearity FeIII/oxo clusters and density functional theory calculations using broken-symmetry methods and the Green's function approach. The three methods gave satisfyingly similar Ji,j values and allowed the identification of spin-frustration effects and the resulting relative spin-vector alignments and thus rationalization of the S = 0 ground state of the cation.

Switchable magnetic, dielectric, conductivity, and phase transition properties of charge-transfer crystals

The properties can be switched between different states and can be used in sensors, displays, and memory devices. In this study, two multi-functional switchable materials [C5-Pmim][Ni(mnt)2] (1) and [C6-Hmim][Ni(mnt)2] (2) (where mnt2-= maleonitriledithiolate, C5-Pmim = 1-pentyl-3-methylimidazolium, and C6-Hmim = 1-hexyl-3-methylimidazolium) have been designed and synthesized, which has segregated cation and anion stacks in the crystal structure. 1 shows two-step switchable dielectric transition with a thermal hysteresis loop accompanying structure phase transition. Dielectric transition of 1 can be attributed to the reorientation of the polar cations and crystal to mesophase transition. Switchable conductivity properties of 1 and 2 were realized by the crystal to mesophase structure transition. The conductivity of the mesophase for 1 and 2 is higher than the corresponding crystal phase. Furthermore, magnetic phase transition with the non-common hysteresis loop for 2 is observed being triggered by the structure and dielectric transition. To the best of our knowledge, this study might be the rare multi-functional switchable examples with dielectric, conductivity, and magnetic transition.

Azide-Locked Prodrug Co-Assembly into Nanoparticles with Indocyanine Green for Chemophotothermal Therapy.

Fabrication of self-delivery drug systems can surmount low drug bioavailability and achieve a precise therapeutic process. In this study, a hydrogen sulfide-responsive (H2S) small molecule prodrug was synthesized by linking two chemotherapy drugs, camptothecin (CPT) and gemcitabine (GT), using a reductive disulfide bond simultaneously with a lock GT strategy using a H2S-responsive azide group (denoted as N3-GT-CPT). The ingenious design endows the easy coprecipitation peculiarity of the prodrug with clinical indocyanine green (ICG) via a combined interaction force of hydrophobic, π-π stacking, and electrostatic interactions of anions and cations, thus producing a more stable and multifunctional therapeutic nanosystem. Considering the great photothermal and imaging ability of ICG, the obtained nanosystem showed an excellent therapeutic ability against colon tumors in vitro and in vivo with selective response to intercellular H2S, thus offering a good combination-based multiple therapy for treatment of tumors.

1,1'-Methyl-enebis(4,4'-bipyridin-1-ium) dibromide.

The asymmetric unit of the title salt, C21H18N4 2+·2Br-, comprises half of the mol-ecule and a bromide ion. The chevron-shaped cations stack as columns in the [001] direction with suitable inter-molecular distance for π-π inter-actions. These cationic columns are further stabilized by inter-columnar C-H⋯N hydrogen bonding with the bromide ions distributed between them.

Anion-π stacks of Lindqvist superoctahedra [Mo6O19]2− supported by caffeinium and theophyllinium cations

Ionic lattices of two new Lindqvist polyoxometalates (HCaf)2[Mo6O19]⋅2EtOH (1) and (HThe)2[Mo6O19]⋅H2O (2) [Caf = caffeine, The = theophylline] reveal extensive anion⋅⋅⋅π interactions, which result in the generation of dense stacks of the electron deficient aromatic cations to the faces of metal-oxide polyhedra with interplanar distances of 2.989(5)-3.048(4) Å and interplanar angles of 2.60(13)-7.35(13)o. These interactions are applicable to the construction of purine/ polyoxometalate solids as special kinds of supramolecular synthons providing linkage of metal-oxide polyhedra through anion⋅⋅⋅π⋅⋅⋅anion links. Hirshfeld surface analysis for the individual anions in 1 and 2 as well as for related structures in CSD supports the relevance of this new interaction for crystal chemistry of polyoxometalates. The total interaction energies of the {(Cation)4[Mo6O19]}2+ synthons are evaluated and compared by using DFT calculations, which suggest larger stability of the (HCaf)+ complexes (–290.3 kcal/mol for 1 and –250.9 for 2) conditioned by additional CH···O contacts involving the methyl groups and the O-atoms of the [Mo6O19]2− anions. Interesting supramolecular assemblies in compounds 1 and 2 have been also rationalized by using molecular electrostatic potential (MEP) surface plots and the noncovalent interaction plot (NCIplot) index. The present structures provide reliable molecular models for geometries and energetics of the stacks subtended by purine bases and polyoxometalate anions that could be relevant for specific targeting of POMs in biomedical systems.

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li3HoBr6–xIx Phases

Ternary lithium halide-based solid electrolytes have attracted broad scientific interest due to their high ionic conductivities in conjunction with good electrochemical stabilities against high-voltage cathode materials. Here, we analyze the structure of the rare earth halide solid solution series Li3HoBr6–xIx and quantify structural defects such as intralayer cation disorder and stacking faults. Almost all members of the solid solution series show strong stacking fault disorder, whereas the intralayer cation disorder systematically increases with increasing iodide content. The substitution of bromide by iodide in Li3HoBr6–xIx leads to an increasing lattice softness and therefore to a higher ionic conductivity and to a lower activation energy. This is counteracted by the increased cation disorder, which also has a strong influence on the ionic conductivity of the solid solution series. Thus, a decrease in ionic conductivity by one order of magnitude is observed when the iodine content exceeds an optimum value. Stacking faults on the other hand do not have a significant impact on the ionic conductivity as the connectivity between neighboring lithium halide octahedra and hence the energy landscape of their migration pathways is not affected for equivalent stacking vectors. The competing factors above give rise to an optimum ionic conductivity at x ≈ 3 with 2.7 × 10–3 S cm–1 at 20 °C and an activation energy of 0.21 eV. While thermal annealing reduces the structural disorder of Li3HoBr6–xIx, the self-healing properties are significantly impeded by mechanical sample treatment, demonstrating the complex interplay between thermal and mechanical effects on the microstructure and, hence, ionic conductivity of layered superionic conductors.

New inversion boundary structure in Sb-doped ZnO predicted by DFT calculations and confirmed by experimental HRTEM

Today, ab-initio calculations are becoming a powerful tool to perform virtual experiments that have the capacity to predict and to reproduce experimentally observed non-periodic features, such as interfaces, that are responsible for quantum properties of materials. In our paper we investigate 2D quantum-well structures, known as inversion boundaries (IB). Combining atomistic modeling, DFT calculations and HRTEM analysis we provide a new fundamental insight into the structure and stability of Sb-rich basal-plane IBs in ZnO. DFT screening for potential IB model was based on the known stacking deviations in originating wurtzite structure. The results show that the model with Aβ−Bα−AβC−γB−βC sequence (IB3) is the most stable translation for Sb-doping, as opposed to previously accepted Aβ−Bα−AβC−γA−αC (IB2) model. The key to the stability of IB structures has been found to lie in their cationic stacking. We show that the energies of constituting stacking segments can be used to predict the stability of new IB structures without the need of further ab-initio calculations. DFT optimized models of IBs accurately predict the experimentally observed IB structures with lateral relaxations down to a precision of ~1 pm. The newly determined cation sublattice expansions for experimentally confirmed IB2 and IB3 models, ΔIB(Zn-Zn) are +81 pm and +77 pm, whereas the corresponding O-sublattice contractions ΔIB(O-O) are –53 pm and –57 pm, respectively. The refined structures will help to solve open questions related to their role in electron transport, phonon scattering, p-type conductivity, affinity of dopants to generate IBs and the underlying formation mechanisms, whereas the excellent match between the calculations and experiment demonstrated in our study opens new perspectives for prediction of such properties from first principles.

Role of Protein-Water Interface in the Stacking Interactions of Granum Thylakoid Membranes-As Revealed by the Effects of Hofmeister Salts.

The thylakoid membranes of vascular plants are differentiated into stacked granum and unstacked stroma regions. The formation of grana is triggered by the macrodomain formation of photosystem II and light-harvesting complex II (PSII-LHCII) and thus their lateral segregation from the photosystem I—light-harvesting complex I (PSI-LHCI) super-complexes and the ATP-synthase; which is then stabilized by stacking interactions of the adjacent PSII-LHCII enriched regions of the thylakoid membranes. The self-assembly and dynamics of this highly organized membrane system and the nature of forces acting between the PSII-LHCII macrodomains are not well understood. By using circular dichroism (CD) spectroscopy, small-angle neutron scattering (SANS) and transmission electron microscopy (TEM), we investigated the effects of Hofmeister salts on the organization of pigment-protein complexes and on the ultrastructure of thylakoid membranes. We found that the kosmotropic agent (NH4)2SO4 and the Hofmeister-neutral NaCl, up to 2 M concentrations, hardly affected the macro-organization of the protein complexes and the membrane ultrastructure. In contrast, chaotropic salts, NaClO4, and NaSCN destroyed the mesoscopic structures, the multilamellar organization of the thylakoid membranes and the chiral macrodomains of the protein complexes but without noticeably affecting the short-range, pigment-pigment excitonic interactions. Comparison of the concentration- and time-dependences of SANS, TEM and CD parameters revealed the main steps of the disassembly of grana in the presence of chaotropes. It begins with a rapid diminishment of the long-range periodic order of the grana membranes, apparently due to an increased stacking disorder of the thylakoid membranes, as reflected by SANS experiments. SANS measurements also allowed discrimination between the cationic and anionic effects—in stacking and disorder, respectively. This step is followed by a somewhat slower disorganization of the TEM ultrastructure, due to the gradual loss of stacked membrane pairs. Occurring last is the stepwise decrease and disappearance of the long-range chiral order of the protein complexes, the rate of which was faster in LHCII-deficient membranes. These data are interpreted in terms of a theory, from our laboratory, according to which Hofmeister salts primarily affect the hydrophylic-hydrophobic interactions of proteins, and the stroma-exposed regions of the intrinsic membrane proteins, in particular—pointing to the role of protein-water interface in the stacking interactions of granum thylakoid membranes.