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High-temperature superconductor (HTS) Josephson junctions (JJs) are primarily based on artificial grain boundaries. Bi-crystal JJs are typically utilized in HTS superconducting quantum interference devices (SQUIDs). However, the performances of bi-crystal JJs depend significantly on the quality of the interface at the junction. In this study, we investigate a method for forming nanobridge JJs via gallium focused ion beam (FIB) irradiation. A 100-nm-thick YBa2Cu3O7- δ was deposited on an MgO (100) substrate via pulsed laser deposition. An additional 20-nm-thick Au layer, which serves as a protection layer preventing ion damage during alignment, was deposited in situ. HTS microchannels with a width of 4 μm were defined via photolithography and argon ion milling. The HTS microchannel widths are decreased via FIB line scans to create nanobridges. The JJs are fabricated using two types of HTS thin films, in which one has a higher critical current density ( J C) that the other. The fabrication process using the gallium FIB was optimized and nanobridges with a junction width of 80 nm were prepared. As a result, a better with higher J C (5 MA/cm2) HTS films allowed for making junctions exhibiting up to five Shapiro steps at 77 K.

We demonstrate a fluid-fluid phase separation in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) membranes using a metal complex lipid of type [Mn(L1)] (1; HL1 = 1-(2-hydroxybenzamide)-2-(2-hydroxy-3-formyl-5-hexadecyloxybenzylideneamino)ethane. Small amount of 1 produces two separated domains in DMPC, whose phase transition temperatures of lipids (Tc) are both lower than that of the pristine DMPC. Variable temperature fluorescent microscopy for giant-unilamellar vesicles of DMPC/1 hybrids demonstrates that visible phase separations remain in fluid phases up to 37 °C, which is clearly over the Tc of DMPC. This provides a new dimension for the application of metal complex lipids toward controlling lipid distributions in fluid membranes.

Amorphous coordination polymers and metal-organic frameworks (MOFs) have attracted much attention owing to their various functionalities. Here, we demonstrate the tunable water adsorption behavior of a series of amorphous cyanide-bridged MOFs with different metals (M[Ni(CN)4]: MNi; M = Mn, Fe, and Co). All three compounds adsorb up to six water molecules at a certain vapor pressure (Pads) and undergo conversion to crystalline Hofmann-type MOFs, M(H2O)2[Ni(CN)4]·4H2O (MNi-H2O; M = Mn, Fe, and Co). The Pads of MnNi, FeNi, and CoNi for water adsorption is P/P0 = 0.4, 0.6, and 0.9, respectively. Although the amorphous nature of these materials prevented structural elucidation using X-ray crystallography techniques, the local-scale structure around the N-coordinated M2+ centers was analyzed using L2,3-, K-edge X-ray absorption fine structure, and magnetic measurements. Upon hydration, the coordination geometry of these metal centers changed from tetrahedral to octahedral, resulting in significant reorganization of the MOF local structure. On the other hand, Ni[Ni(CN)4] (NiNi) containing square-planar Ni2+ centers did not undergo significant structural transformation and therefore abruptly adsorbed H2O in the low-pressure region. We could thus define how changes in the bond lengths and coordination geometry are related to the adsorption properties of amorphous MOF systems.

Metal node design is crucial for obtaining structurally diverse coordination polymers (CPs) and metal?organic frameworks with desirable properties; however, FeII ions are exclusively six-coordinated. Herein, we present a cyanide-bridged three-dimensional (3D) CP, FePd(CN)4, bearing four-coordinate FeII ions, which is synthesized by thermal treatment of a two-dimensional (2D) six-coordinate FeII CP, Fe(H2O)2Pd(CN)4?4?H2O, to remove water molecules. Atomic-resolution transmission electron microscopy and powder X-ray and neutron diffraction measurements revealed that the FePd(CN)4 structure is composed of a two-fold interpenetrated PtS topology network, where the FeII center demonstrates an intermediate geometry between tetrahedral and square-planar coordination. This four-coordinate FeII center with the distorted geometry can act as a thermo-responsive flexible node in the PtS network.

The ortho-isomer of molecular hydrogen (o-H2) was converted to the para-isomer (p-H2) within 600 s by using Prussian blue analogs, {MII3[CrIII(CN)6]2} (MCr; M = Mn and Ni), as nuclear-spin conversi...

Two-dimensional Hofmann-type coordination polymers of type Mn(H2O)2[Pd(CN)4]·xH2O (1·xH2O; x = 0, 1, and 4), Mn(H2O)(MeOH)[Pd(CN)4]·2MeOH (2·2MeOH), and Mn(MeOH)2[Pd(CN)4]·MeOH (3·MeOH) have been synthesized. The homosolvent-bound 1·4H2O, 1·H2O, and 3·MeOH polymers consist of undulating layer structures, whereas the structure of heterosolvent-bound 2·2MeOH consists of "Janus-like" flat layers in which water-bound and MeOH-bound-sides are present. 1·4H2O and 1·H2O exhibited anisotropic two-dimensional thermal expansions involving structural transformations of the undulating layers; one layer axis expands while the other contracts. 2·2MeOH exhibits anisotropic thermal expansion in which the flat layers shift sideways as the temperature is increased, with colossal interlayer expansion occurring (αc = +200 MK-1 over 140-180 K, αc = +165 MK-1 over 200-280 K). 3·MeOH also showed colossal interlayer expansion (αc = +216 MK-1) together with expansion of the undulating layers.

A homochiral one-dimensional (1D) Mn(III) coordination polymer [MnL]n (1) was synthesised employing the N3O-donor tetradentate ligand (L = 2-hydroxy-N-[2-[[(2-aminophenyl)methylene]amino]-2-methylpropyl]-benzamide). The X-ray structure of 1 and its magnetic properties were investigated in detail. The crystal structure of 1 shows a homochiral helical arrangement in which spontaneous resolution has occurred, despite the ligand being achiral. Magnetic characterization revealed an antiferromagnetic interaction between manganese(III) ions (J = −2.48 cm−1, g = 1.96) that leads to an antiferromagnetic spin-ordering phase transition at TN ≈ 7 K. Noteworthily, 1 exhibits weak ferromagnetism with a relatively large coercive field of 3.0 kOe based on the spin canting, indicating the formation of a homochiral weak ferromagnet.

The 2D coordination polymers, [Mn(salen)]2[PtII(CN)4]1-x[PtIV(CN)4(I2)]x (salen = N,N'-ethylenebis(salicylideneaminato), x = 0.18 (1), 0.45 (2), 0.85 (3)), have been synthesized via consecutive oxidative additions of iodine to the 2D undulating layers in [Mn(salen)]2[PtII(CN)4]. The presence of I-Pt-I chains perpendicular to the layers and the inhomogeneity of individual I-Pt-I sites were demonstrated. The I-Pt-I chains in 3 give rise to an absorption band involving the excitation that arises from an antibonding nature orbital to the corresponding bonding nature orbital between iodides in the I-Pt-I bridging units. Moreover, variable-temperature X-ray powder diffraction patterns and Raman spectra for 1 and 2 indicate that some I-Pt-I sites display different vibrational energies that are associated with the contraction of the zigzag 2D layers.

Cell membranes contain lateral systems that consist of various lipid compositions and actin cytoskeleton, providing two-dimensional (2D) platforms for chemical reactions. However, such complex 2D environments have not yet been used as a synthetic platform for artificial 2D nanomaterials. Herein, we demonstrate the direct synthesis of 2D coordination polymers (CPs) at the liquid-cell interface of the plasma membrane of living cells. The coordination-driven self-assembly of networking metal complex lipids produces cyanide-bridged CP layers with metal ions, enabling "pseudo-membrane jackets" that produce long-lived micro-domains with a size of 1-5 μm. The resultant artificial and visible phase separation systems remain stable even in the absence of actin skeletons in cells. Moreover, we show the cell application of the jackets by demonstrating the enhancement of cellular calcium response to ATP.

The ability to tune physical properties is attractive for the development of new materials for myriad applications. Understanding and controlling the structural dynamics in complicated network structures like coordination polymers (CPs) is particularly challenging. We report a series of two-dimensional CPs [Mn(salen)]2[M(CN)4]·xH2O (M = Pt (1), PtI2 (2), and MnN (3)) incorporating zigzag cyano-network layers that display composition-dependent anisotropic thermal expansion properties. Variable-temperature single-crystal X-ray structural analyses demonstrated that the thermal expansion behavior is caused by double structural distortions involving [Mn(salen)]+ units incorporated into the zigzag layers. Thermal relaxations produce structural transformations resulting in positive thermal expansion for 2·H2O and negative thermal expansion for 3. In the case of 1·H2O, the relaxation does not occur and zero thermal expansion results in the plane between 200 to 380 K. The present study proposes a new strategy base...

Lipid packaged iron(II) complex of [Fe(C5C10C12-trz)3](C12-Glu)2 (1) [C5C10C12-trz = 4′,5‴-decyl-1‴-(heptadecyloxy)-1,2,4-triazole, C12-Glu = 4-(1,3-bis-dodecyloxycarbonyl-propylcarbamoyl)-benzenesulfonic acid] have been successfully synthesized and characterized using TEM, DSC, PXRD and magnetic susceptibility. It was observed that lipid packaged compound displayed liquid crystalline phase at room temperature. Furthermore, lipid packaged compound exhibited spin crossover phenomena accompanying the phase transition from liquid crystalline to liquid crystalline.

Ca2-αLaαNb3-βXβO10 nanosheets ((α, β=0-0.14), X= Rh(LaRh), Mn(LaMn), Fe(LaFe), Ni(LaNi)) were synthesized by exfoliation using the surfactant aided sonication method. These nanosheets demonstrated superior photocatalytic activities for water splitting into hydrogen at room temperature. SEM-EDX images and spectra confirmed the morphology and composition of the materials where doped metal precursors inserted into the heterogeneous structure aided the photocatalytic activity.

µ-Oxo bridged dinuclear iron(III) complex with trialkylated tridentate ligand [Fe2(µ-O)(3C8-bzimpy)2Cl4]·CHCl3 (1, and 3C8-bzimpy = 2,6-bis(N-octylbenzimidazol-2′-yl)-4-octyloxypyridine) was synthesized and the magnetic property was investigated. Single crystal X-ray structural analysis of complex 1 revealed µ-oxo bridged dinuclear structure with N3OCl2 donor set. Complex 1 has constructed one-dimensional chain structure by CH–π interactions and CH–Cl hydrogen bonds, and further formed a two-dimensional layer parallel to the ab plane by fastener effect of trialkylated ligands. Magnetic susceptibility measurement of 1 showed the antiferromagnetic interactions through µ-oxo bridge, and the best fits for their behavior gave the following parameters: J = −12.7 cm− 1, g = 2.

Two tetranuclear Ni(II) clusters, [Ni(L1)(µ3-OCH3)(CH3OH)]4·5CH3OH (1) and [Ni(L2)(µ3-OCH3)(CH3OH)]4 (2) (HL1 = methyl 2-hydroxy-3-methoxybenzoate; HL2 = 4-(1,1,3,3-tetramethylbutyl)phenyl salicylate) were synthesized and characterized by X-ray crystallography and magnetic properties. Both complexes have [Ni4O4] cubane cores assembled with four triply-bridged methoxy oxygens. The temperature-dependent magnetic susceptibilities for 1 and 2 show ferromagnetic interactions between Ni(II) ions. The best fit parameters for their magnetic behaviors are J1 = + 9.32 cm−1, J2 = − 1.66 cm−1 and g = 2.24 for 1, and J1 = + 9.82 cm−1, J2 = − 1.98 cm−1, g = 2.21 for 2, respectively.

High dielectric constants (er) were observed in two-dimensional composites obtained from stacking of reduced graphene oxide (RGO) with Ca2Nb3O10 and with TiO2 nanosheets. The relative dielectric permittivity values of the composites were found to be higher than 105, an amazingly high value compared to that of similar GO composites and other common dielectric materials. As a consequence, we considered application of the hybrids as super dielectric materials in high capacitance supercapacitors. The route to high capacitance involves the variation of oxygen vacancies within the surface and in the closest bulk interior of the hybrids. The effective charges generated throughout the metal oxide and carbon–oxygen polar bonding systems within the graphene skeleton appear to highly influence dielectric polarization. Moreover, the replenishment of oxygen vacancies at the RGO and metal oxide interface also contributes to polarizability.

Iron(III) spin-crossover (SCO) complexes [Fe(qsal)2]BS·MeOH·H2O (1), [Fe(qsal)2](NS)·MeOH (2), [Fe(qnal)2](NS) (3), and [Fe(qnal)2]PS·MeOH·CH2Cl2 (4) (Hqsal, N-(8-quinolinyl)salicylaldimine; Hqnal, N-(8-quinolinyl)-2-hydroxy-1-naphthaldimine; BS, benzenesulfonate; NS, 1-naphthalenesulfonate; PS, 1-pyrenesulfonate) have been synthesized and characterized by X-ray structure determinations and temperature-dependent magnetic susceptibility measurements. The aromatic counteranions BS, NS, and PS can be used for the tuning of intermolecular coupling through a variety of weak interactions. All of the complexes show temperature-dependent SCO behavior. but the light-induced excited spin-state trapping (LIESST) effect was observed only for 1, 3, and 4 when the samples were illuminated (λ 808 nm) for 1 h at 5 K. In particular, 59% of the LS form of 1 was converted to the metastable HS state by illumination, equal to the highest degree of conversion yet known for LIESST in [Fe(qsal)2]+ derivatives. The lack of a LIESST effect for 2 may be due to the relatively limited degree of interaction between the cations and anions in the lattice, reflected in a much longer minimum Fe···Fe separation in this complex in comparison to the others.

Zinc(ii) and platinum(ii) complexes [M(X-4-C18-salmmen)] (M = Zn (1) and Pt (2), X = R, S (optical isomer) and rac (racemate), salmmen = N,N'-monomethylenebis-salicylideneimine) were synthesized and investigated. The series of compounds represented by 1 (R, S and rac forms) display liquid crystalline state behaviour at 413 K, and exhibit both ferroelectric and fluorescence properties, while the compounds represented by 2 (R and S, and rac forms) do not display liquid crystal behaviour but do exhibit ferroelectric and fluorescence properties. The ferroelectric behaviour was confirmed by second harmonic generation (SHG) experiments. It is considered that the motion and fluctuation of the long alkyl chains in these complexes results in the observed ferroelectric properties.

Wheel-type heptanuclear heterometallic clusters of stoichiometry [Ni7−xMx(HL)6(μ3-OMe)4(μ3-OH)2]Cl2 (L = 1-(2-hydroxy-3-methoxybenzamido)-2-(benzylideneamino)ethane; M = Zn2+, Co2+, Mn2+; x = 1, 3) were synthesized, and their metal ion dependent ferromagnetic properties were investigated. It was demonstrated that the central position of each cluster was occupied by a Ni2+ ion while other metal ions (Zn2+, Co2+ or Mn2+) were accommodated in peripheral positions. The magnetic interactions, anisotropy and magnetization of the resultant clusters were all influenced by the combinations of metal ions present.

The cobalt(ii) complex incorporating π-conjugated substituent, [Co(Naph-C2-terpy)2](BF4)2 (1; Naph-C2-terpy = 4'-(2-naphthoxy(ethoxy))-2,2':6',2''-terpyridine), exhibits an abrupt spin transition (ST) behavior (cooperative factor C = 0.91) while its solvated product, 1·2MeOH, shows gradual spin crossover (SCO) behavior (C = 0.49). Single crystal X-ray structural analyses demonstrated that the octahedral coordination core [CoN6] in 1 shows larger distortion in both high-spin and low-spin states than solvated 1·2MeOH or another two derivatives, [Co(R-terpy)2](BF4)2 (R = 2-naphthyl (2), 9-anthracenyl (3)). The respective distortion parameters (Σ) are compared with those for previously reported SCO cobalt(ii) compounds. The highly-distorted [CoN6] core in 1 (Σ = 126 in the HS state and 101.6 in the LS state) was stabilized by strong intermolecular interactions and observed an abrupt ST behaviour.

Stable single phase mixed electron/proton conductor with excellent capacitance property from oxygen functionalized porous carbon (OPC) has been presented herein. Electrochemical study suggested that at room temperature and 90%RH the values of electronic and prototonic conductivity of OPC are 1.68 × 10-3 Scm-1 and 3.14 × 10-5 Scm-1, respectively. Moreover, the specific capacitance of 204 Fg-1 at 10 mVs-1 is observed. The improved electrochemical performance of OPC mostly associated with transformation of high temperature treated inert carbon into an electrochemically active substance and ionic movement associated with oxygen functionalized groups in carbon surface during oxidation.

π-π stacking between GO and Benzene sulfonic acid (BS) / Naphthalene sulfonic acid (NS) / Pyrene sulfonic acid (PS) / Naphthalene disulfonic acid (ND) has resulted in the respective GO-BS, GO-NS, GO-PS and GO-ND proton conductive hybrid. The conductivity follows the trend as GO-NS ˃ GO-BS ˃ GO-PS ˃ GO ˃ GO-ND. GO-NS possesses the maximum interlayer distance with exhibiting seven times higher proton conductivity compared with GO. Evidently, π-π stacking of sulfonic acid derivatives with GO can adopt it as superionic conductor.

In contrast to monofunctional electrocatalysts for oxygen evolution reaction (OER), hydrogen evolution reaction (HER) or oxygen reduction reaction (ORR), trifunctional catalysts for simultaneously ...

Both p- and n-type field effect transistors (FET) properties have been observed in undoped reduced graphene oxide (rGO). Short and long time exposure of GO during photo reduction results in the formation of respective p- and n-type rGO semiconductor. Achieving duel behavior of this type in an undoped material is exceedingly unusual. Herein we report the presence of such behavior in the reduced from of graphene oxide (rGO) for the first time.

Within the nanopores, junctions and interlayer void space (IVS) in graphene oxide film (GOf), we report that IVS function as the key semipermeable site during sieving. The GOf could filter only dye molecules having nanometer-ranged dimensions. Tinier hydrated ions with angstrom-ranged dimensions couldn't be sieved by GOf. Nature and extent of this molecular sieving property have been justified by observing sieving efficacy and flow times for aqueous solutions of dyes, inorganic salts and their mixtures. GOf also could separate the dyes from mixtures with salts. The flow time followed the trend as: mixtures > salt solutions > dye solutions. PXRD data reveal entering of dye molecules at IVS during sieving. Obviously, a part of dye molecules leaking through the nanopores and junctions of GOf, finally become trapped at the IVS. IVS, therefore has been recognized as the key semipermeable site for molecular sieving in GO. With exploring the insight features of molecular sieving in GOf, this report clearly indicates that IVS needs to be tuned to adopt GOf for various analytical aspects including water purification, desalination and organic inorganic separation.

Zero in-plane thermal expansion (TE) in a two-dimensional (2D) coordination polymer is demonstrated. The combination of components that expand and those that shrink into zigzag layers results in no net area change in the 2D materials with temperature. Single crystals of [Mn(salen)]2[Mn(N)(CN)4(guest)] (salen = N,N′-ethylenebis(salicylideneaminato), guest = MeOH and MeCN) were prepared, and variable-temperature single-crystal X-ray structural analyses demonstrated that these compounds exhibited both anisotropic positive and negative thermal expansion depending on the guest species. The TE behavior results from distortions of the octahedral coordination geometry of [Mn(salen)]+ units in the zigzag layers. When both guests MeOH and MeCN were incorporated into one material, [Mn(salen)]2[Mn(N)(CN)4(MeOH)0.25(MeCN)0.75], zero in-plane TE resulted in a range of temperature between 380 and 440 K.

Chiral iron(II) complexes, [Fe{(R)-L}2(NCS)2] (1) and [Fe{(S)-L}2(NCS)2] (2), and racemic complex [Fe(rac)-L)2(NCS)2] (3) {L = α-methyl-N-(2-pyridinylmethylene)cyclohexanemethanamine} were synthesized. Their structures and magnetic properties were investigated by X-ray crystallography, magnetic susceptibility measurements, and Mossbauer spectroscopy. Complexes 1 and 2 crystallize in the trigonal system with space group P3121 and P3221, respectively. All complexes exhibit spin-crossover (SCO) behavior and light induced excited spin state trapping (LIESST) effects at 532 nm. Complexes 1 and 2 show similar gradual SCO behavior, and complex 3 shows more gradual SCO, which seems to be a result of the different crystal packing, as complex 3 is the symmetric isomer but 1 and 2 are asymmetric.

Hybrid materials that are obtained from intercalation of different polar and hydrophilic acid guest molecules within graphene oxide (GO) have been found to exhibit high proton conductivity. The accommodation of these guest precursors within the GO interlayer takes place through weak physical forces. PXRD patterns with enhanced interlayer distance confirmed successful intercalation processes. Raman and IR spectral data reveal the absence of any covalent bond between the functional groups of the guest and the GO host. TGA data confirms improved water adsorbing capacity of the hybrids. At ambient conditions and 90% relative humidity (RH), a RH dependent impedance study shows that intercalation of formic acid (FA) and phosphoric acid (PA) within GO results in ∼7 times higher proton conductivity compared with that for the pristine GO sample. The low activation energy values suggest that proton conduction in the samples is aided by the Grotthuss mechanism. Improvement in the water adsorbing capacity is primarily responsible for such high proton conductivity. The current study suggests that cheap and environmentally friendly GO-based intercalated hybrid materials, such as GO/PA and GO/FA with enhanced proton conductivity, can be appropriate replacements for the expensive Nafion-based solid electrolytes.

We reported the proton conductivities of a series of oxidized fullerenes (fullerenols) having varied polarity and hydrophilicity. The samples were generated from the oxidation of fullerenes by using different oxidation techniques and oxidizing agents. XPS, IR and TGA data confirmed the successful oxidation of fullerenes. Electrochemical impedance showed that fullerenols can support proton conductivity. At room temperature and 90% RH, a maximum proton conductivity of 1.4 × 10−2 S cm−1 was observed in fullerenols obtained from the oxidation of fullerene (C60) by caustic soda. We expect the use of fullerenols as solid electrolytes in fuel cells, sensors, chemical filters and so on.

A morphology transformation of hybrid liposomes was shown to occur from spherical vesicles to tubular micelles when increasing the ratio of the metal complex lipid present. Phase transition temperatures increased while viscosities decreased, indicating that the hybrids exhibit stronger interaction between heads but weaker interaction between alkyl chains than occurs in pristine liposomes.

The behavior of single-ion magnets (SIMs) that reflects large distortions of their coordination environments caused by the packing of long alkyl chains for two Co(II) complexes of the type [Co(Cn-t...

Luminescent ZnII clusters [Zn4 L4 (μ3 -OMe)2 X2 ] (X=SCN (1), Cl (2), Br (3)) and [Zn7 L6 (μ3 -OMe)2 (μ3 -OH)4 ]Y2 (Y=I- (4), ClO4- (5)), HL=methyl-3-methoxysalicylate, exhibiting blue fluorescence at room temperature (λmax =416≈429 nm, Φem =0.09-0.36) have been synthesised and investigated in detail. In one case the external heavy-atom effect (EHE) arising the presence of iodide counter anions yielded phosphorescence with a long emission lifetime (λmax =520 nm, τ=95.3 ms) at 77 K. Single-crystal X-ray structural analysis and time-dependent density-functional theory (TD-DFT) calculations revealed that their emission origin was attributed to the fluorescence from the singlet ligand-centred (1 LC) excited state, and the phosphorescence observed in 4 was caused by the EHE of counter anions having strong CH-I interactions.

A highly stable composite from in situ growth of silicon oxycarbide phases (SiOC) within reduced graphene oxide (rGO) has been synthesized. The resulted SiOC/rGO anode exhibits high porosity, reversible Li intercalation capacity and a cycling stability of 507 mAhg−1 at 100 mAg−1 (50 cycles).

The effect of interlayer distance and oxygen content on proton conductivity of graphite oxide is presented. Bulk-state proton conductivities were measured using coin-shaped pellets of three different graphite oxide samples, namely, H-GO, S-GO, and B-GO, generated respectively from the techniques of Hummers, Staudenmaier, and Brodie. The extent of oxidation, nature of functional groups, interlayer distances, and morphologies are studied through Raman spectroscopy, XPS, powder XRD pattern, and SEM images. The proton conductivities follow the trend H-GO > S-GO > B-GO. In the XPS study, the total oxygen contents were found to follow the trend H-GO > B-GO > S-GO, whereas the interlayer distances obtained from the powder XRD patterns show the trend H-GO > S-GO > B-GO. Beside the nature of the functional groups and extent of oxidation, the interlayer distance displays a significant effect on the proton conductivity values. The temperature-dependent Arrhenius plots reveal the activation energy (Ea) of the samples...

Fe[((py)im-C16) 3 ](BF 4 ) 2 ( 1 ) and Fe[((py)imH) 3 ](BF 4 ) 2 ( 2 ), the Iron(II) compounds with C16 long alkyl chain appended (py)imH and unmodified (py)imH [(py)imH = 2-(2-pyridyl)imidazole] have been synthesized and characterized by NMR, IR spectra and elemental analysis. For containing C16 long alkyl chain, complex 1 exhibits the liquid crystalline property around room temperature. The magnetic study suggests that 1 exists only in low spin state but 2 exhibits gradual spin crossover behavior. These observation suggests the possibility for synchronizing liquid crystallinity and spin crossover behavior of (py)imH complex in near future.

An antimalarial drug artesunate (ATS) was encapsulated in both functionalized MCM-41 and ordinary MCM-41 with an excellent loading capacity and sustained release behavior for possible biomedical applications.

Cobalt–iron Prussian blue analogues are magnetic functional compounds that exhibit charge-transfer-induced spin transition (CTIST), however, the role of guest species such as water in influencing the magnetic behaviour has remained unclear. Here, we report the water-dependent CTIST behaviour of Na0.46Co[Fe(CN)6]0.78(H2O)1.31 together with its single crystal X-ray structural analysis, for the first time.

Acetaldehyde gas sensing using hybrids of reduced graphene oxide (rGO) and transition metal elements, rGO–M (M = oxide/hydroxide of Mn, Fe, Co and Ni) has been investigated. Thin films of GO, rGO and rGO–M on conductive glass were deposited through simple and affordable techniques and characterized using Raman spectroscopy, powder X-ray diffraction patterns, field emission scanning electron microscopy and electrical conductivity measurements. Concentration dependent resistances during the oxidation of acetaldehyde gas in air (10 to 50%) were investigated by using a sensing probe devised from rGO, GO–M and the rGO–M hybrids, of which rGO–Ni exhibited the maximum sensitivity. In rGO–Ni, in combination with rGO the NiOOH precursor can capture electrons (generated from acetaldehyde oxidation) through the holes, while indicating rGO–Ni to be a p-type semiconductor. This report implies the possibility of developing inexpensive graphene based p-type semiconductors for sensing other gases as well.

The metal atom of the title compound is four coordinated. The asymmetrically appended Cl atom and a widely spread π-conjugated system of the complex mol­ecule construct the supra­molecular structures of a hydrogen-bonded chain and a π–π inter­acted column., The title complex, [Ni(C20H14ClN3O)], with an asymmetrically chloride-appended Schiff base ligand has been synthesized and structurally characterized at 100 K. In the compound, the central nickel(II) ion has a square-planar coordination geometry with N3O donors of the π-conjugated tetra­dentate Schiff base ligand. In the crystal, the complexes are connected into an inversion dimer via an Ni⋯Ni inter­action [3.1753 (5) Å] and a pair of π–π inter­actions [centroid–centroid distance = 3.8416 (16) Å]. The dimers are linked via a C—H⋯Cl hydrogen bond, forming a chain along the c-axis direction. The dimer chains inter­act with each other through π–π inter­actions [centroid–centroid distance = 3.8736 (16) Å], forming a layer expanding parallel to the ac plane.

A sextuply linked capsule incorporating two Ni(ii) cubane units is formed when Ni(ii) salts are reacted with N-aminoalkyl salicylamidato ligands in a 4 : 3 ratio in methanol. With a short (propyl) alkyl substituent, additional chloride counter ions are included in the cavity by occupation of one apex of each of the linked cubanes, while with a longer (pentyl) substituent, perchlorate and tetrafluoroborate anions are included, probably by H-bonding involving hydroxyl groups on the inner apices of the cubanes, indicating that the cavity can be regarded as suited to binding of hydrophilic units despite the lipophilic character of its links. The dicubane capsules show ferromagnetic behaviour typical of Ni(ii) cubanes in general, with coupling constants dependent upon the nature of the salt-derived counter anions.

A graphene oxide (GO) and ruthenium(II) complex with bromine-substituted terpyridine ligand, [Ru(Br-terpy)2]Cl2 (Br-terpy: 4′-bromo-2,2′:6′,2′′-terpyridine), reacts to form a GO–[Ru(Br-terpy)2]2+ h...

Tuneable pressure effects associated with changing interlayer distances in two-dimensional graphene oxide (GO)/reduced GO (rGO) layers are demonstrated through monitoring the changes in the spin-crossover (SCO) temperature (T1/2) of [Fe(Htrz)2(trz)](BF4) nanoparticles (NPs) incorporated in the interlayer spaces of the GO/rGO layers. The interlayer separation along the GO to GO/rGO-NP composites to rGO series decreases smoothly from 9.00 Å (for GO) to 3.50 Å (for rGO) as the temperature employed for the thermal reduction treatments of the GO-NP composites is increased. At the same time, T1/2 increases from 351 K to 362 K along the series. This T1/2 increment of 11 K corresponds to that observed for pristine [Fe(Htrz)2(trz)](BF4) NPs under a hydrostatic pressure of 38 MPa. The influence of the stacked layer structures on the pseudo-pressure effects has been further probed by investigating the differences in T1/2 for [Fe(Htrz)2(trz)](BF4) that is present in the composite as larger bulk particles rather than as NPs.

Two ferromagnetic multinuclear Ni(II) clusters, [Ni4L14(μ3-OMe)4(CH3OH)4] (1) and [Ni7(HL2)6(μ3-OMe)6]Cl2 (2), and a mononuclear complex [NiL3]·2H2O (3) (HL1 = benzyl 2-hydroxy-3-methoxybenzoate; H2L2 = 1-(2-hydroxy-3-methoxybenzamido)-2-(benzylideneamino)ethane; H2L3 = 1-(2-hydroxy-3-methoxybenzamido)-2-(pyridylmethyleneamino)ethane) were synthesised, and their structures and magnetic behaviours were investigated in detail. 1 has a [Ni4O4] cubane structure while 2 has a wheel-like [Ni@Ni6] arrangement. The temperature-dependent magnetic susceptibilities for 1 and 2 are in accord with the presence of dominating intra-cluster ferromagnetic interactions between Ni(II) ions. The best fits for their behaviours gave the following parameters: J1 = 11.06 cm−1, J2 = 1.43 cm−1, g = 2.29 for 1, and J1 = 6.87 cm−1, J2 = −3.41 cm−1, g = 2.24 for 2.

Self-assembled hybrid supramolecular architectures formed between amphiphilic anions and long alkylated cationic cobalt(II) complexes of type [Co(Cn-terpy)2](C12-Glu)2 (n = 15–20) have been synthesized and characterized by TEM, PXRD and magnetic susceptibility measurements. The hybrids display wire or rolled sheet supramolecular arrangements with odd and even alkyl chain dependence, with the cobalt(II) centres exhibiting gradual spin-crossover behaviours.

Slight changes in the coordination structure of the manganese(V)-nitrido anionic complex, [MnV(N)(CN)4]2−, induced by using a “lipid package” approach markedly made an impact on the corresponding redox potentials. The single crystals of four lipid assemblies, [dabco-(CH2)n−1-CH3]2[Mn(N)(CN)4(H2O)]·xH2O (n = 15, 16, 17 and 18; dabco = 1,4-diazabicyclo[2,2,2]octane), were synthesized and solid-state cyclic voltammetric studies demonstrated that the [MnV(N)(CN)4]2− anions with smaller “cross” NC–Mn–CN bond angles exhibit higher redox potentials. The observed trend reflects the energy change associated with the structural transformation from [MnV(N)(CN)4]2− to [MnVI(N)(CN)4]2− and is supported by the results of DFT calculations. The NC–Mn–CN bond angles in the flexible [Mn(N)(CN)4]2− structure exhibit excellent correlation with the redox potentials of the complexes in the solid state.

The nature of the molecular assemblies formed in the crystalline state by cobalt(II) terpyridine (terpy) complexes incorporating appended adenine (A) or thymine (T) bases was found to be controlled by which bases are present. Single-crystals of the cobalt(II) complexes [Co(A-C6-terpy)2 ](BF4 )2 (1) and [Co(T-C6-terpy)2 ](BF4 )2 (2) have needle and block habits, respectively. Subsequent mixing of 1 and 2 in MeOH resulted in isolation of [Co(A-C6-terpy)1.5 (T-C6-terpy)0.5 ](BF4 )2 (3) as plate-like crystals. A 3D network structure is present in 1 that incorporates 1D chains, whereas 2 adopts a 2D stacked structure constructed from ladder-type assemblies. For 3, "dimer-rings" consisting of [Co(A-C6-terpy)2 ]2+ and [Co(A-C6-terpy)(T-C6-terpy)]2+ units are generated by means of base-pairing between A and T. Notably, 3 displays the first crystal structure of a heteroleptic cobalt(II) complex of [Co(A-C6-terpy)(T-C6-terpy)](BF4 )2 . These assembly differences involving the terpyridine cobalt(II) complex units in 1-3 affect the cooperativities influencing their spin crossover (SCO) behavior. The influence of the terminal nucleobases on the resulting assembly has been probed by investigating the co-crystallization of [Co(terpy)2 ](BF4 )2 (4) with [Co(C6-terpy)2 ](BF4 )2 (5) and 1 with 5.

Insertion of 3-hydroxypropanesulfonicacid (HPS) at graphene oxide (GO) interlayer results in high proton conductivity (10-2 - 10-1 Scm-1) due to the improvement in oxygen content, interlayer distance and water absorbing capacity. This result indicates that hydroxyalkylsulfonicacid can be a perfect guest molecules for improving the proton conductivity of carbon materials.

A highly stable proton conductor has been developed from carbon sphere oxide (CSO). Carbon sphere (CS) generated from sucrose was oxidized successfully to CSO using Hummers' graphite oxidation technique. At room temperature and 90 % relative humidity, the proton conductivity of thin layer CSO on microsized comb electrode was found to be 8.7×10(-3) S cm(-1) , which is higher than that for a similar graphene oxide (GO) sample (3.4×10(-3) S cm(-1) ). The activation energy (Ea ) of 0.258 eV suggests that the proton is conducted through the Grotthuss mechanism. The carboxyl functional groups on the CSO surface are primarily responsible for transporting protons. In contrast to conventional carbon-based proton conductors, in which the functional groups decompose around 80 °C, CSO has a stable morphology and functional groups with reproducible proton conductivity up to 400 °C. Even once annealed at different temperatures at high relative humidity, the proton conductivity of CSO remains almost unchanged, whereas significant change is seen with a similar GO sample. After annealing at 100 and 200 °C, the respective proton conductivity of CSO was almost the same, and was about ∼50 % of the proton conductivity at room temperature. Carbon-based solid electrolyte with such high thermal stability and reproducible proton conductivity is desired for practical applications. We expect that a CSO-based proton conductor would be applicable for fuel cells and sensing devices operating under high temperatures.

The host-guest composites of Hofmann-type iron(II) spin-transition (ST) porous coordination polymers incorporating guest molecules show guest-dependent ST behavior in accordance with the respective guest species, which may be a gas, solvent, halogen, or organic molecule. The guest also works as a chemical stimulant to switch the spin state of the host between high and low spin at room temperature. In this review, we discuss guest properties including size, shape, flexibility, chemical properties, and pore loading content, which impact the spin states of the host framework and the ST behavior exhibited by the host-guest composites.