Tuning the dimensionality in chiral and racemic organic/tin hybrids with halides.

Chiral 1D tin iodides EBASnI3 were synthesized while incorporating enantiomerically pure and racemic ethylbenzylammonium (EBA) cations between the 1D shared inorganic corners. The dimensionality was reduced to 0D when replacing iodine with bromine. In all the cases, the presence of hydrogen bonds was observed between the organic part and the inorganic part, while transfer of chirality was evidenced for the EBASnI3 enantiomerically pure compounds.

Alloxazine-Based Ligands Appended with Coordinating Groups: Synthesis, Electrochemical Studies, and Formation of Coordination Polymers.

Three new ligands based on the alloxazine core appended with pyridyl coordinating groups have been designed, synthesized, and characterized. The ligands are revealed to be redox-active in DMF solution, as attested to by CV and combined CV/EPR studies. The spin of the reduced species appears to be delocalized on the alloxazine core, as attested to by DFT calculations. The coordination abilities of one of the ligands toward Cu2+ or Ni2+ 3d cations revealed the formation of the first alloxazine-based 3D coordination polymers, presenting strong π-π stacking and substantial cavities. Preliminarily charge/discharge experiments in Li batteries evidence Li+ insertion in such systems.

Tuning Crystal Packing and Magnetic Properties in a Series of [Dy12] Metallocubanes Based on Azobenzene Derivatives of Salicylic Acid.

A series of four new Dy12 dodecanuclear clusters based on azobenzene derivative ligands of salicylic acid (L1-L4) has been synthesized and characterized in the crystalline phase using X-ray diffraction on single crystal and powder, IR spectroscopy, elemental analysis, and DSC-TGA methods. It was revealed that all obtained clusters exhibit the formation of the similar metallic cluster nodes, as vertex-sharing heterocubanes, obtained from four Dy3+ cations, three bridging hydroxyl groups, and O atoms from the salicylic ligands. The coordination geometry around the Dy(III) centers has been carefully analyzed. Whereas Dy12-L1 and Dy12-L2 with L1 and L2 containing Me and OMe groups in para positions of the phenyl rings, respectively, form similar porous 3D diamond-like molecular networks due to CH-π interactions, for Dy12-L3 with L3 bearing NO2-electron-withdrawing group, the generation of 2D molecular grids assembled by π-π staking is observed, and for Dy12-L4 with L4 bearing phenyl substituent, 3D hexagonal channels have been generated. The complexes Dy12-L1, Dy12-L2, and Dy12-L3 exhibit a zero-field slow magnetic relaxation effect. After UV irradiation of Dy12-L1, a decrease of the magnetic anisotropy energy barrier displaying the possibility of control over magnetic properties by the external stimulus has been observed.

Selective gas adsorption by calixarene-based porous octahedral M32 coordination cages.

Giant octahedral M32 coordination cages were prepared via self-assembly of sulfonylcalix[4]arene-supported tetranuclear M(II) clusters (M = Co, Ni) with hybrid linker based on tris(dipyrrinato)cobalt(III) complexes appended with peripherical carboxylic groups. Due to intrinsic and extrinsic porosity, the obtained solid-state supramolecular architectures demonstrated good performance as adsorbents for the separation of industrially important gases mixtures.

An accurate vibrational signature in halogen bonded molecular crystals.

The far infrared (FIR) and Raman fingerprints of the halogen bond in two representative 1D halogen bonded networks based on the recognition of TFIB, tetrafluorodiiodobenzene, with piperazine or azopyridine, have been accurately identified. It was demonstrated that the signature of the halogen bonding in the solid state, especially the N⋯I signal can be simply and directly evidenced in the far infrared region. The DFT theoretical calculations identified the N⋯I interaction in the molecular crystals and allowed estimation of the corresponding energies and distances of the involved halogen bonds, in accordance with the cristallographic data.

Chemical and Electrochemical Alkali Cations Intercalation/Release in an Ionic Hydrogen Bonded Network.

The chemical oxidation of a hydrogen bonded network, formed upon combination of a hydrogen bond donor dication (12+, a dicationic bis-amidinium organic moiety bearing four propyl chains) with [FeIII/II(CN)6]3-/4- anions has been studied using vibrational spectroscopies. The postsynthetic oxidation of the microcrystalline powder of X213-[FeII(CN)6]2 (X = Na, K, and Cs) by S2O82- into 13-[FeIII(CN)6]2 appeared to be partial for X = K+ and Cs+ and total for Na213-[FeII(CN)6]2. It corresponds to a two-step process involving a second order reaction. The reaction time appears to be dependent on the nature of the alkali cation and is faster for X = Na+. The integrity of the hydrogen bonded network, after oxidation, was also confirmed by powder X-ray diffraction. The flexible nature of the hydrogen bonded network allows alkali cation motions within the network during the oxidation process. In addition, the investigation of the electrochemical behavior evidenced an amorphous deposition on a gold electrode immersed into a solution containing (12+ and [FeIII(CN)6]3-) after 100 cycles. This is the first evidence of an electrochemical ion intercalation for a molecular hydrogen bonded network.

Partially Reversible Thermal-Induced Oxidation During a Dehydration Process in an H-bonded Supramolecular System.

The thermal behaviour of an H-bonded molecular network A based on [FeII (CN)6 ]4- anions and organic bisamidium cations 12+ was investigated. Heating was found to induce the partial oxidation of [FeII (CN)6 ]4- into [FeIII (CN)6 ]3- , together with a thermochromic effect and also a loss of crystallinity was evidenced from mid and far FT-IR spectroscopic data, XRPD and DSC/TGA analysis. Rehydration also partially reversed the redox reaction and its colour, and after that, a mixture of A with an amorphous phases was observed. FT-IR spectroscopy revealed that the oxidation of Fe(II) was accompanied by a deprotonation of the cation.

Box-like gel capsules from heterostructures based on a core-shell MOF as a template of crystal crosslinking.

New polymer capsules (PCs) were obtained using a crystal crosslinking (CC) method on core-shell MOF crystals. The latter are based on the epitaxial growth of two isostructural coordination polymers which are then selectively crosslinked. Decomposition of the non-reticulated phase leads to new PCs, possessing a well-defined hollow cubic shape reflecting the heterostructure of the template.

Molecular tectonics: hierarchical organization of heterobimetallic coordination networks into heterotrimetallic core-shell crystals.

Combinations of a neutral Pt(ii) organometallic tecton bearing two triphenylphosphine and two 3-ethynylpyridyl coordinating moieties in trans positions with MX2 complexes (M = Co(ii) and X = Cl- or Br- and M = Zn(ii) and X = Cl-) lead to the formation of isostructural 1D heterobimetallic coordination compounds. By 3D epitaxial growth processes, using coordination bonding, heterotrimetallic core-shell crystals are generated by the growth of crystalline layers on seed crystals.

Welding Molecular Crystals.

Both for fundamental and applied sciences, the design of complex molecular systems in the crystalline phase with strict control of order and periodicity at both microscopic and macroscopic levels is of prime importance for development of new solid-state materials and devices. The design and fabrication of complex crystalline systems as networks of crystals displaying task-specific properties is a step toward smart materials. Here we report on isostructural and almost isometric molecular crystals of different colors, their use for fabrication of core-shell crystals, and their welding by 3D epitaxial growth into networks of crystals as single-crystalline entities. Welding of crystals by self-assembly processes into macroscopic networks of crystals is a powerful strategy for the design of hierarchically organized periodic complex architectures composed of different subdomains displaying targeted characteristics. Crystal welding may be regarded as a first step toward the design of new hierarchically organized complex crystalline systems.

Atypical stoichiometry for a 3D bimetallic oxalate-based long-range ordered magnet exhibiting high proton conductivity.

The reproducible formation of a 3D oxalate based coordination compound of formula (NH4)5[Mn(II)2Cr(III)3(ox)9]·10H2O, with an unusual Mn(II)/Cr(III) ratio, is presented. The original topology of the anionic network leads to antiferromagnetic long-range ordering whereas its guests favour high humidity-dependent proton conductivity.

Molecular tectonics: from crystals to crystals of crystals.

The in situ combination of M(II) cations (Co, Ni, Cu or Zn) with 2,4,6-pyridinetricarboxylic acid as a ligand, a bisamidinium dication as a H-bond donor tecton and NaOH leads to the formation of anionic metal complexes ML2(2-) and their interconnection into isomorphous 3D H-bonded networks displaying different colours which were used as preformed seed crystals for the formation of crystals of crystals by 3D epitaxial growth.

Molecular tectonics: tuning the dimensionality and topology of extended cyanocuprate networks using a bisamidinium cation.

Upon combining KCu(CN)2 with six different symmetrical dicationic bisamidinium moieties possessing different shapes and geometries, seven new coordination networks of the cyanocuprate type displaying 1-, 2- and 3-D dimensionality have been obtained. The formation of networks results from the interconnection of Cu(i) centres by cyanide anions through different bridging modes. The organic dicationic tectons interact with the anionic networks by charge-assisted H-bonds and, depending on their geometric features, they play different structuring roles. In the case of the 1D cyanocuprate networks, the organic cation interconnects consecutive anionic chains, increasing thus the overall dimensionality of the arrangement to 2D. For the 2D networks, either riveting or intercalation has been observed. For the riveting case, either the process takes place only between two consecutive sheets leading to a double layer type arrangement and thus without an increase of dimensionality, or between consecutive 2D networks in an alternate fashion. In the latter case, the dimensionality of the overall architecture is increased to 3 as for the intercalated case. For the 3D architectures, the dicationic moieties are located within the generated channels.

The odd association of a C(3h) trisamidinium cation and tosylate anion with a series of linear oxalate-bridged trinuclear heterometallic complexes.

A series of six isostructural heterometallic trinuclear oxalate-bridged complexes of the formula (TDbenz)(2)(TsO)(2)[M(II)(H(2)O)(2){(µ-ox)M(III)(ox)(2)}(2)]·6H(2)O·2CH(3)OH (TDbenz = 1,3,5-tris[2-(1,3-diazolinium)]benzene; TsO = 4-methylbenzenesulfonate; ox = oxalate; M(III) = Fe, M(II) = Mn (1), Fe (2), Co (3); M(III) = Cr, M(II) = Mn (4), Fe (5), Co (6)) have been synthesized from (NH(4))(3)[M(III)(ox)(3)]·3H(2)O, the chloride salts of the divalent metal ions and the tosylate salt of 1,3,5-tris[2-(1,3-diazolinium)]benzene (trisamidinium). Whereas the crystal structures of compounds 2, 3, 4 and 5 have been investigated by single-crystal X-ray diffraction, the structures of 1 and 6 have been checked by X-ray powder diffraction. All six compounds are isostructural and crystallise in the P1 space group. The crystals are composed of discrete linear [M(II)(H(2)O)(2){(µ-ox)M(III)(ox)(2)}(2)](4-) trinuclear bimetallic units, trisamidinium and tosylate ions and solvent molecules. The linear trinuclear unit is based on a central trans-diaquametal(II) entity connected to two [M(III)(ox)(3)](3-) (M(III) = Cr(III), Fe(III)) moieties through oxalate bridges. The divalent metal ions, surrounded by six oxygen atoms, adopt a distorted octahedral coordination geometry. The coordination sphere is composed of four oxygen atoms belonging to two oxalate ligands and two trans-coordinated water molecules. One of the oxalate ions is coordinated to the central metal centre whereas the other two oxalate ligands are non-bridging. In the crystal, intermolecular hydrogen bonds involving oxalate ligands, solvent molecules and the counter-ions form a complex 3D network. Variable-temperature magnetic susceptibility measurements indicate an antiferromagnetic interaction between the iron(III) and the metal(II) ions (J = -4.23, -6.73, -8.97 cm(-1) for 1, 2 and 3 respectively) whereas this interaction is ferromagnetic when iron(III) is replaced by chromium(III) (J = +1.21, +2.20, +3.63 cm(-1) for 4, 5 and 6 respectively). Moreover, the cobalt(II) derivatives exhibit high D values (D = 29.3 cm(-1) for and D = 27.4 cm(-1) for 6).

Giant core-shell nanospherical clusters composed of 32 Co or 32 Ni atoms held by 6 p-tert-butylthiacalix[4]arene units.

Using combinations of p-tert-butylthiacalix[4]arene (TCA) and [M(DMSO)(6)(BF(4))(2)] salts (M = Co(II) or Ni(II)), two almost isostructural core-shell-type thermally stable giant nanoclusters, composed of 32 metal centers, 6 deprotonated calix units binding the metal centers by both their O and S atoms, 24 µ-oxo or µ-hydroxo bridging groups, and 6 MeOH molecules, have been prepared under mild and reproducible conditions. For both giant clusters, the oxidation state II [M(II)(32)O(16)(OH)(8)(CH(3)OH)(6)TCA(6) (M = Co or Ni)] for the metal center was demonstrated by X-ray photoelectron and electronic absorption spectroscopies.

From tectons to luminescent supramolecular ionic liquid crystals.

New phosphorescent and room-temperature liquid-crystalline materials were obtained by combining dicyanometallate anions with dicationic bisamidinium based tectons bearing four peripheral lipophilic pyrogallate moieties.

Molecular tectonics: crystal engineering of mixed valence Fe(II)/Fe(III) solid solutions.

Based on isostructurality between crystals formed upon combining the dicationic tecton 2 with either M(3)Fe(III)(CN)(6) or M(4)Fe(II)(CN)(6) (M = Cs), a rare example of an H-bonded mixed valence Fe(ii)-Fe(iii) solid solution ((Cs(2)2(3)-[Fe(II)(CN)(6)](2))(0.83)(2(3)-[Fe(III)(CN)(6)](2))(0.17))) and curious necklace-like composite crystals were generated.

Molecular tectonics: design of 2-D networks by simultaneous use of charge-assisted hydrogen and coordination bonds.

Using a combination of charge-assisted H- and coordination-bonds, a tetra component system composed of a dicationic and a dianionic organic tecton, Ag(+) cation and XF(6)(-) (X= P, As, Sb) anion behaves as planned and leads to the formation of 2-D isostructural networks for which the energetic contributions of the two recognition events dominate the construction process.

In situ reduction of Fe(iii) into Fe(ii): an example of post-crystallisation transformation.

Upon exposing crystals made of a combination of an amidinium based dication and [Fe(III)(CN)(6)](3?) anion to a hydroalcoholic solution of hydrazine and KCl, the reduction of Fe(iii) to Fe(ii) with concomitant incorporation of K(+) cation takes place in the crystalline phase.

Molecular tectonics: 3-D organisation of decanuclear silver nanoclusters.

The combination of silver nitrate with a thiacalix[4]arene derivative bearing at the lower rim four benzonitrile groups leads in the crystalline phase to the formation of a 3-D coordination network in which the organic tectons are connected by decanuclear silver nanoclusters.