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International audience; The synthesis and characterization of novel chelate nitrogen ligands with phasmidic tails (pyridine-triazole ligand 1b; 2,2'bipyrimidine ligands 2b and 3b) is reported, as well as their titanium (IV) coordination complexes. The analogous ligands 1a, 2a and 3a with methoxy substituents instead of the tails were also synthesized, together with titanium complexes that could be crystallographically characterized. A good agreement is noticed between analytical data of the complexes in solution (NMR) and in the solid state (X-ray diffraction). The complexes are overall stable on phases like alumina or silica, so that they could be characterized by TLC and sometimes chromatographied. Supramolecular architectures were generated from an equimolar solution of titanium (IV) isopropoxide, ligand 1a and a polyphenol ligand 5-H4, leading to a double-stranded helicate characterized by MS, NMR and crystallography, which was then converted into a trinuclear complex as shown by MS and NMR DOSY data. The liquid-crystalline behaviour of the ligands 1b, 2b and 3b incorporating the long alkyl tails, and of the complexes derived from these ligands, has been investigated.

Spin-crossover (SCO) active transition metal complexes are a class of switchable molecular materials. Such complexes undergo hysteretic high-spin (HS) to low-spin (LS) transition, and vice versa, rendering them suitable for the development of molecule-based switching and memory elements. Therefore, the search for SCO complexes undergoing abrupt and hysteretic SCO, that is, bistable SCO, is actively carried out by the molecular magnetism community. In this study, we report the bistable SCO characteristics associated with a new series of iron(ii) complexes-[Fe(BPP-CN)2](X)2, X = BF4 (1a-d) or ClO4 (2)-belonging to the [Fe(BPP-R)2]2+ (BPP = 2,6-bis(pyrazol-1-yl)pyridine) family of complexes. Among the complexes, the lattice solvent-free complex 2 showed a stable and complete SCO (T1/2 = 241 K) with a thermal hysteresis width (ΔT) of 28 K-the widest ΔT reported so far for a [Fe(BPP-R)2](X)2 family of complexes, showing abrupt SCO. The reproducible and bistable SCO shown by the relatively simple [Fe(BPP-CN)2](X)2 series of molecular complexes is encouraging to pursue [Fe(BPP-R)2]2+ systems for the realization of technologically relevant SCO complexes.

International audience; This article describes highly luminescent ionic compounds in liquid and crystalline states, where a naphthalene moiety is conjugated to an imidazolium center decorated with alkyl chains of different lengths. We have characterized, by X-ray diffraction of a single crystal and the liquid, that these compounds are organized in rod-shaped assemblies. The formation of this molecular architecture is governed by ionic interactions that dominate those of the lesser π–π and van der Waals interactions. Consequently, aromatic naphthalene rings are confined to the environment of alkyl chains (diluted in an apolar solvent), thus avoiding the extinction of luminescence by the formation of chromophore excimers, as shown in photophysical data.

Spin-crossover (SCO) active transition metal complexes are a class of switchable molecular materials. Such complexes undergo hysteretic high-spin (HS) to low-spin (LS) transition, and vice versa, rendering them suitable for the development of molecule-based switching and memory elements. Therefore, the search for SCO complexes undergoing abrupt and hysteretic SCO, that is, bistable SCO, is actively carried out by the molecular magnetism community. In this study, we report the bistable SCO characteristics associated with a new series of iron(II) complexes-[Fe(BPP-CN)(2)](X)(2), X = BF4 (1a-d) or ClO4 (2)-belonging to the [Fe(BPP-R)(2)](2+) (BPP = 2,6-bis(pyrazol-1-yl)pyridine) family of complexes. Among the complexes, the lattice solvent-free complex 2 showed a stable and complete SCO (T-1/2 = 241 K) with a thermal hysteresis width (Delta T) of 28 K-the widest Delta T reported so far for a [Fe(BPP-R)(2)](X)(2) family of complexes, showing abrupt SCO. The reproducible and bistable SCO shown by the relatively simple [Fe(BPP-CN)(2)](X)(2) series of molecular complexes is encouraging to pursue [Fe(BPP-R)(2)](2+) systems for the realization of technologically relevant SCO complexes.

International audience; The aim of this work is to provide a better understanding of the interface between graphite and different molecular and ionic liquids. Experimental measurements of the liquid surface tension and of the graphite-liquid contact angle for sixteen ionic liquids and three molecular liquids are reported. These experimental values allowed the calculation of the solid/liquid interfacial energy that varies, for the ionic liquids studied, between 14.5 mN m−1 for 1-ethyl-3-methylimidazolium dicyanamide and 37.8 mN m−1 for 3-dodecyl-1-(naphthalen-1-yl)-1H-imidazol-3-ium tetrafluoroborate. Imidazolium-based ionic liquids with large alkyl side-chains or functionalized with benzyl groups seem to interact more favourably with freshly peeled graphite surfaces. Even if the interfacial energy seems a good descriptor to assess the affinity of a liquid for a carbon-based solid material, we conclude that both the surface tension of the liquid and the contact angle between the liquid and the solid can be significant. Molecular dynamics simulations were used to investigate the ordering of the ions near the graphite surface. We conclude that the presence of large alkyl side-chains in the cations increases the ordering of ions at the graphite surface. Benzyl functional groups in the cations lead to a large affinity towards the graphite surface.

We present an efficient Ullmann-type synthesis methodology enabling the preparation of imidazolium compounds with an extended aromatic core in three steps. This procedure begins with a microwave-assisted, heterogeneously catalysed cross-coupling reaction in the presence of Cu(II)-doped NaY zeolite to obtain imidazole-aromatic derivatives directly in good yield. The innovation is that this reaction does not require solvent, ligand or an inert atmosphere. Subsequently, these derivatives have been alkylated with bromoalkanes and the bromide of the imidazolium products exchanged for [BF4]− or [PF6]− anions. We have studied the influence of the methyl group (inductive effect) on the aromatic unit during the coupling reaction as well as its impact on different arrangements in the crystalline state. We have been able to extend this synthesis to ionic liquid crystal compounds which display lamellar self-organization (smectic A). The mesomorphic behavior and phase transition temperatures were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS).

We describe the proficient synthesis and thermotropic mesomorphicity of thioether–functionalized imidazolium–type ionic liquids containing C12 and C18 chains associated with Br− and OTf− anions. The mesomorphic behavior and phase transition temperatures were studied by Polarizing Optical Microscopy (POM), Differential Scanning Calorimetry (DSC) and Small-Angle X-ray Scattering (SAXS). The ionic liquids with bromide anion display Smectic A lamellar phase giving homeotropic and fan-shaped textures. The layered crystallographic structure is reported by Single-Crystal XRD. The electrochemical characteristics of the ionic liquids with C18 side chain have been determined via Cyclic Voltammetry.

Correction for ‘Luminescent imidazolium–naphthalene salts in liquid and solid states’ by Matthieu L’Her et al., New J. Chem., 2019, 43, 12529–12532.

Ionic liquid Crystals constitute highly versatile materials that have drawn much interest these past few years in the fields of academic research and industrial development. In this respect, the present article is intended as an update of K. Binnemans review published in 2005, but focusing exclusively on the imidazolium cation - the most widely studied. Herein, imidazolium-containing thermotropic liquid crystalline materials will be sorted by molecular structure (mono-, bis-, poly-imidazolium compounds, with symmetrical and non-symmetrical structures) and discussed. Their physico-chemical properties will be exposed in order to adduce the relevancy and potential of the imidazolium platform in various fields of research.

A smectogenic 1,3-bis(4-decyloxyphenyl)-3H-imidazol-1-ium trifluoromethane sulfonates (1) was studied on the drift mobility of carriers by a Time-Of-Flight (TOF) technique. The transient photocurrent decay curves were clearly observed for the positive electrode illumination and the transit times could be detected to indicate the mobility in the smectic A (SmA) phase is on the order of 10−3 cm2 V−1 s−1. This carrier mobility is too fast if it is a reflection of ionic transport in this system and is more easily explained on the basis of electronic charge hopping process.

1,3-Bis(4-alkyloxyphenyl)-3H-imidazol-1-ium trifluoromethanesulfonates, alkyl = CH3(CH2)n–1, n = 8, 10, 12, 14 and 16, can be derived from the analogous 4-alkyloxyphenylamines. These imidazolium salts exhibit a lamellar liquid-crystal mesophase between 99 °C and 191 °C. The smectic-A phase was fully characterised by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction. We report also the synthesis, lamellar crystal structure and catalytic activity of the PdII complex of the (deprotonated) carbene form of one of these salts. In addition, we measured the charged carrier mobilities in the mesophase.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Very stable copper(I) complexes were engineered from pyridine ligands bearing on one side an iminophenyl fragment and on the other a pivotal methyl group. The phenyl group was substituted in the para position either by a methoxy group or by a phenyl ester group grafted with three paraffin chains (n = 8, 12, 16). The methoxy complex in the crystalline state was characterized by X-ray diffraction. Its molecular structure was found to correspond to a distorted tetrahedral arrangement round the copper(I) metal centre. The long-chain complexes near room temperature were found to produce columnar liquid crystals of hexagonal symmetry. The columns were found to result from the aggregation of the wedge-shaped molecules round the columnar axis with the metal-containing iminopicoline ligands crowded together in the centre and the alkyl chains pointing outwards with a disordered conformation. The degree of molecular aggregation, around 7, was found to decrease significantly on heating.

The preparation of mono-, di- and trisubstituted gallic derivatives is described using either 1-bromododecane or 12-bromo-1-dodecanol. After saponification of the methyl ester bearing the dodecanol groups, subsequent functionalization with methacryloyl chloride provides the hybrid methacrylate esters/anhydride species. Selective cleavage of the anhydride function gives rise to the corresponding acids, which have been further functionalized to the imine derivative 15 by condensation with 4-[imino-4-(toluyl)]phenol. This reaction is made possible using the acidic form of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC·HCl) and dimethylaminopyridine (DMAP). Selective hydrolysis of the imine function with a HCl-treated silica provides the targeted aniline in excellent yield.

Recent advances in the fields of liquid crystals and supramolecular chemistry have led to the discovery of mesomorphic metallo-helicates formed by selective complexation of non-mesomorphic oligopyridinic ligands built from flexible imino-appendages. Different types of mesophases, ranging from columnar to ordered smectic biaxial, have been generated. In cases where the segmented ligand is adequately engineered, gliding of the coordinated ligands across the metal centers present in the emergent dinuclear complex is made possible by the provision of ancillary imino binding sites and this behavior facilitates liquid-crystalline properties at room-temperature, after supercooling. Furthermore, formation of a mesogenic mixed-valence complex following selective oxidation has been realized. An attempt is made to provide insight on how the strategy of using imino-based oligopyridinic scaffolds permits generation of liquid-crystalline materials with morphologies determined by their molecular components.

Ligand L, containing two 6-methyl-6′-methyl-yl-2,2′-bipyridine moieties linked by a “PhPO” spacer, has been prepared. Subsequent complexation with [Cu(CH3CN)4](BF4) led to a unique complex of formula [CuL](BF4). The molecular structure has been determined by X-ray crystallography in the solid state and NMR studies in solution. The complex displays an intense absorption band in the visible wavelength range with maxima at 418 and 509 nm, and is oxidised reversibly at +0.66 V (ΔEp = 80 mV) to the corresponding Cu(II) species, while two successive reductions of the coordinated bipyridine fragments occur at −1.60 (ΔEp = 66) and −1.84 V (ΔEp = 70 mV) s. SCE. Direct spectrophotometric titrations with global analysis allowed us to elicit stability constants for the emergent complex and to highlight the formation of a dinuclear complex in the presence of excess copper.

Unsymmetric functionalization of 5-bromo-2,2'-bipyridine and 5,5'-dibromo-2,2'-bipyridine with 4-n-alkoxyphenylethynyl leads to two new families of mesomorphic compounds. The smectic B, smectic A and nematic phases observed were studied by polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction. The structural parameters of the smectic phases were determined. The internal structure of the smectic phases, particularly the range of the in-layer ordering of the molecules, was investigated as a function of temperature.

Copper(I) binds to 2,7-diimino-1,8-naphthyridine in solution to form a mixture of equilibrating mono- and polynuclear complexes, as identified by electrospray MS and monitored by UV-visible spectrophotometric titrations, including a binuclear metallo-helicate for which X-ray data are available but whose formation does not require cooperative associations.

The synthesis of novel symmetrical liquid crystalline compounds based on 5-methyl-5-[2-(4-alkyloxyphenyl)-2-hydroxyethyl]-2,2-bipyridines is reported, together with some physical properties. Although the chelating head-groups are connected via a chiral sp3 carbon atom, all the materials are mesomorphic. Intermolecular hydrogen bonding between pyridino and hydroxy fragments in the mesophases is made apparent by FTIR spectroscopy.

A columnar structure with lamellar morphology in the liquid crystalline state is displayed by the palladium complex salt 1, which is synthesized from nonmesogenic ligands.

Eine columnare Struktur mit lamellarer Morphologie zeigt im flussigkristallinen Zustand das Palladiumkomplexsalz 1, das aus nicht mesogenen Liganden hergestellt wird.

The preparation of 1,3-bis-(4-dodecyloxy-phenyl)-3H-imidazol-1-ium trifluoro-methanesulfonate is described from the 4-dodecyloxy phenylamine derivative. This new imidazolium salt exhibits a lamellar liquid crystal mesophase between 119 and 172 °C. The Smectic A phase has been characterised by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction. In addition the lamellar crystallographic structure obtained on single crystal is reported and corroborated the self-assembly of molecules in the mesomorphic state.

5,5′-[(4-Hexadecyloxyphenyl)ethynyl]-2,2′-bipyridine was synthesized by a palladium(O) cross-coupling reaction. Its thermotropic liquid crystalline behaviour was analysed using differential scanning calorimetry, polarizing microscopy, and X-ray diffraction. Three enantiotropic tilted smectic phases were identified upon heating: SF, SI, and SC.

Dissymmetric functionalization of 5,5′-dimethyl-2,2′-bipyridine with a ‘stilbene type’ chromophore bearing a terminal alkoxy group leads to a new family of mesomorphic compounds exhibiting a rich thermotropic polymorphism. A succession of smectic B, smectic A and nematic phases was observed. For the octyloxy compound, an additional phase was detected which was hexatic in symmetry.

Functional hybrid materials on the basis of inorganic hosts and ionic liquids (ILs) as guests hold promise for a virtually unlimited number of applications. In particular, the interaction and the combination of properties of a defined inorganic matrix and a specific IL could lead to synergistic effects in property selection and tuning. Such hybrid materials, generally termed ionogels, are thus an emerging topic in hybrid materials research. The current article addresses some of the recent developments and focuses on the question why silica is currently the dominating matrix used for (inorganic) ionogel fabrication. In comparison to silica, matrix materials such as layered simple hydroxides, layered double hydroxides, clay-type substances, magnetic or catalytically active solids, and many other compounds could be much more interesting because they themselves may carry useful functionalities, which could also be exploited for multifunctional hybrid materials synthesis. The current article combines experimental results with some arguments as to how new, advanced functional hybrid materials can be generated and which obstacles will need to be overcome to successfully achieve the synthesis of a desired target material.

The anodic behaviour of the ferrocenyl-derived compounds [Ph 2 PCH 2 C(O)(η 5 -C 5 H 4 ) Fe(η-C 5 H 5 )] ( 1 ), [( o -C 6 H 4 CH 2 NMe 2 )PdPh 2 PCHC(O)(η 5 - C 5 H 4 )Fe(η 5 -C 5 H 5 )] ( 2 ) and [( o -C 6 H 4 CH 2 NMe 2 )Pd-ClPh 2 PCH 2 C(O)(η 5 -C 5 H 4 )Fe(η 5 -C 5 H 5 )] ( 3 ) has been investigated in dichloromethane at a platinum electrode. Voltammetric and coulometric data, and spectral results, indicate that for each compound, the first electron loss corresponding to the oxidation of the ferrocenyl centre triggers an intramolecular electron transfer. In complexes 2 and 3 , this results in the formation of transient radical cationic Pd III species whereas for 1 the electron transfer probably leads to a phosphonium cation radial.

The reactions of K[Fe{Si(OMe)3}(CO)3(P∼Y)][P∼Y=Ph2PCH2C(O)Ph, Ph2PCH2C(O)[(η-C5H4)FeCp] (Cp=η5-C5H5), Ph2P(CH2)2CN] with CdCl2·2.5H2O, ZnX2 (X=Cl, I) or InCl3 afforded Fe-Cd-Fe or Fe-M(μ-X)2M-Fe (M=Cd, Zn, In;X=Cl, I) and Fe-InCl2 complexes. Some of them contain an unusual and labile μ-η2-SiO alkoxysilyl bridge which may be associated with a bridging mode for the ketophosphine ligand (first such example structurally established), thus providing original results in bimetallic chemistry on the intramolecular coordination of oxygendonor functions ofchemically different hemilabile ligands firmly attached to a neighboring metal center. The structures of the trinuclear complex (3), of the chlorobenzene solvate of the tetranuclear complex (4a·C6H5Cl) and of [mer-(OC)3{(EtO)3Si} (4e) have been determined by X-ray diffraction. Crystals of 3 are orthorhombic, space groupPbcn, witha=19.010(4),b=11.766(5),c=26.998(7)A, andZ=4. Crystals of4a·C6H5Cl are monoclinic, space groupC2/c witha=22.455(3),b=17.680(2),c=16.627(4)A, β=90.80(4)°, andZ=4. Crystals of4e are monoclinic, space groupC2/c witha=25.392(5),b=18.554(6),c=16.28(1)A, β=120.73(3)°, andZ=4. The structures were solved using direct methods and Fourier difference techniques and refined by blocked full-matrix least squares toR=0.035 (Rw=0.049) for 2719 observed reflections, toR=0.042 (Rw=0.056) for 3082 observed reflections, and toR=0.057 (Rw=0.075) for 1850 observed reflections for3, 4a·C6H5Cl and4e, respectively. The Fe-Zn complexes (9a), (9b) and (9c) were prepared and characterized by spectroscopic methods.

The reaction of cis-[ Pd{Ph 2 PCHC(O )Ph}2] (1) with HBF4/H2O instantly leads to the formation of the cationic complex cis-[ Pd{Ph 2 PCH 2 C(O )Ph}2][BF4]2. When 1 was treated with commercial BF3·Et2O, containing HBF4 as an impurity, the related compound cis-[ Pd{Ph 2 PCH 2 C(O )Ph}2][BF4][B2F7] (2) was formed. The structure of 2 was determined by an X-ray diffraction study. The compound ctystallizes in the orthorhombic system, P212121 space group, Z=4, cell dimensions: a=16.474(4), b=19.007(5), c=12.932(4) A, V=4049.3 A3, final R=0.030. The two chelating phosphines define puckered five membered metallocycles characterised by PCH2 carbon atoms lying significantly out of the metal coordination plane (−0.617(7) A for C1 and +0.779(7) A for C21). This study establishes the first structural data for the B2F7− anion: the value of the BFbridgeB angle is 128.1(7)°. The values of the BFbridge bond lengths (1.50(1) and 1.51(1) A are significantly longer than the other BF bonds (1.34–1.39 A).

Treatment of K[Fe(CO)3{Si(OMe)3}(dppm-P)](dppm = Ph2PCH2PPh2) with CdX2(X = Cl or Br) in tetrahydrofuran (thf) in a 1 : 1 ratio afforded the tetranuclear iron–cadmium complexes mer-[{[(MeO)3Si](OC)3[graphic omitted](µ-X)}2]2a(X = Cl) and 2b(X = Br) in 78 and 65% isolated yield, respectively. Each Fe–Cd bond is supported by a dppm ligand. The reaction of the ketophosphine-substituted metalate K[Fe(CO)3{Si(OMe)3}{Ph2PCH2C(O)Ph}] with CdCl2 in a 1 : 1 ratio similarly afforded mer-[{[(MeO)3Si](OC)3[graphic omitted](µ-Cl)}2]2c, in which a bridging mode for the functional (P,O) ligand is assumed for the first time. Reaction of K[Fe(CO)3{Si(OMe)3}(dppm-P)] with ZnCl2 afforded the Fe–Zn analogue 3, which is very labile. Similarly, Fe–Hg complexes of the type mer-[{(MeO)3Si}(OC)3[graphic omitted]X](R = Et, X = Ph; R = Me, X = C6Cl5 or Cl) were prepared. The chloride bridges of 2a are easily split by nucleophiles. Using Ph2PCH2C(O)Ph, mer-[{(MeO)3Si}(OC)3[graphic omitted]Cl{Ph2PCH2C(O)Ph}] and mer-[{(MeO)3Si}(OC)3[graphic omitted]gCl{Ph2PCH2C(O)Ph}] were obtained. They reacted with Tl[PF6] to yield cationic complexes in which the ketophosphine acts as a chelating ligand. The synthesis of the Fe–TlIII complex mer-[{(MeO)3Si}(OC)3[graphic omitted](lC6F5)2]9 is also described. The 31P-{1H} NMR resonance due to the phosphorus bound to thallium consists of a doublet of doublets at δ–14.0 with 1J(P–203Tl/205Tl)= 6765 Hz. The molecular structure of complex 2a was determined by X-ray diffraction. Crystals of the hexane solvate are orthorhombic, space group Pbcn, with a= 23.498(9), b= 16.856(8), c= 18.220(8)A, and Z= 4. The structure has been solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix least squares to R= 0.0653 for 2906 observed reflections. In the dimeric complex, having an imposed C2 symmetry, the two Fe–Cd distances, 2.624(2)A, are indicative of metal–metal bonds and the two Cd atoms are joined by a double nearly symmetrical chloride bridge. A phosphorus atom of the dppm ligand completes the co-ordination of the Cd atom. Each Fe atom is octahedrally co-ordinated by three carbonyl groups in a meridional arrangement, by a phosphorus atom of the dppm ligand, by the Si atom of the Si(OMe)3 ligand and by the Cd atom.

We have shown that copper and cobalt metallosurfactants derived from Cu(II) and Co(III) complexes of a macrobicyclic hexamine ("cage") can form wormlike micelles in aqueous solution that may coexist with or easily interconvert with vesicle structures. The cylindrical micelle structures are unusual for triple-chain surfactants with a single headgroup and are not easily accounted for using geometrical packing arguments. The solution behavior has been characterized by cryo-TEM and SAXS measurements. Both the Cu and Co compounds display viscoelastic solutions at 1 wt %, indicating that such behavior may be anticipated for the full variety of stable metal complexes formed by the cage headgroup, auguring applications based on the incorporation of metallo aggregates into mesoporous silica structures.

Wenowpresentastrategyforamoreversatileexploita-tionofliquid-crystaltemplateeffects,whichisillustratedbythe electrolysis of imidazolium liquid crystals containingdicyanoargentate(I)anddicyanoaurate(I)anionstoproducesilverandgoldnanoparticles.Thekeytothisapproachisthecouplingoftheself-organizationoftheimidazoliummetallatetotheuseofelectrochemicalreduction,thelatterprovidingthe means to control the particle size and form of theelectrodeposited metals by variation of parameters such asthepotentialandthecurrentdensity.Many mesomorphic imidazolium salts can be readilypreparedbysimplemetathesisreactionsinvolvingprecipita-tion from aqueous solutions containing the appropriateanions. In investigating this chemistry, we sought to useanionsincorporatingtransitionmetalstoendowtheproductswith properties such as redox activity and variable conduc-tivity.Thus,wehavesynthesizeddicyanoargentate(I)(1)anddicyanoaurate(I)(2)derivativesof3-(4-dodecyloxybenzyl)-1-methyl-1H-imidazolium in good yield(over 80%) from thebromidestartingmaterial(Scheme1).

The new ionic liquid crystal 1-(4-dodecyloxybenzyl)-3-methyl-1H-imidazol-3-ium bromide has been synthesized and its X-ray structure obtained; various salts containing BF4−, SCN−, PF6−, CF3SO3−, (CF3SO2)2N− have been prepared by anion metathesis in water from bromide species as starting materials, and finally, the mesomorphism and electrochemical behavior have been investigated.

A variety of mono-oxidized pyridine, bipyridine, terpyridine, and pyridine/pyridazine are readily prepared under mild conditions using Pyrolusite MnO2. This phase has been characterized by means of X-ray powder diffraction and scanning electron microscopy. The oxidative activity is in keeping with the nature, morphology, and surface area of the MnO2 reagent.

Novel liquid crystalline compounds based on 5-methyl-5′-(4-n-alkoxyphenylvinyl)-2,2′-bipyridine were synthesized and their mesomorphic properties investigated. All members of this series exhibit nematic, smectic A and smectic B phases. For the octyloxy compound an hexatic phase is also observed.

Strong hydrogen bonding has been observed in mesomorphic phenanthroline compounds engineered from diacylaminobenzene platforms: a columnar organization is found in the free ligands (n = 12 or 16) whereas a smectic arrangement is evidenced in a palladium complex (n = 16).

A columnar structure with lamellar morphology in the liquid crystalline state is displayed by the palladium complex salt 1, which is synthesized from nonmesogenic ligands.

Strong hydrogen bonding has been observed in mesomorphic phenanthroline compounds engineered from diacylaminobenzene platforms: a columnar organization is found in the free ligands (n = 12 or 16) whereas a smectic arrangement is evidenced in a palladium complex (n = 16).

A newly-synthesized 4′-[bis(diphenylphosphino)methane]–2,2′∶6′,2 ″-terpyridine-based (dppm–terpy) ligand forms complexes by selective complexation of the terpy or diphos segment, respectively, with Fe(II) or Pd(II) salts; in the latter case, an X-ray structural analysis reveals the formation of a neutral square-planar complex assembled from the deprotonated ligands.

In the presence of copper(I), certain di- and tri-topic ligands derived from reaction of substituted anilines with 2-pyridinecarbaldehyde or 2,6-pyridinedicarbaldehyde form a new type of polycatenar metallomesogen around the tetrahedral metallic centre.