Low Molecular Mass Gelators of Organic Liquids and the Properties of Their Gels

This critical review presents a comprehensive study of transition-metal carboxylate clusters which may serve as secondary building units (SBUs) towards construction and synthesis of metal–organic frameworks (MOFs). We describe the geometries of 131 SBUs, their connectivity and composition. This contribution presents a comprehensive list of the wide variety of transition-metal carboxylate clusters which may serve as secondary building units (SBUs) in the construction and synthesis of metal–organic frameworks. The SBUs discussed here were obtained from a search of molecules and extended structures archived in the Cambridge Structure Database (CSD, version 5.28, January 2007) which included only crystals containing metal carboxylate linkages (241 references).

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Secondary building units, nets and bonding in the chemistry of metal–organic frameworks

Synthesis of 3d metallic single-molecule magnets

Organic-inorganic hybrid materials promise both the superior carrier mobility of inorganic semiconductors and the processability of organic materials A thin-film field-effect transistor having an organic-inorganic hybrid material as the semiconducting channel was demonstrated Hybrids based on the perovskite structure crystallize from solution to form oriented molecular-scale composites of alternating organic and inorganic sheets Spin-coated thin films of the semiconducting perovskite (C(6)H(5)C(2)H(4)NH(3))(2)SnI(4) form the conducting channel, with field-effect mobilities of 06 square centimeters per volt-second and current modulation greater than 10(4) Molecular engineering of the organic and inorganic components of the hybrids is expected to further improve device performance for low-cost thin-film transistors

https://science.sciencemag.org/content/sci/286/5441/945.full.pdf

Organic-inorganic hybrid materials as semiconducting channels in thin-film field-effect transistors

The nature and characteristics of the CH/π interaction are discussed by comparison with other weak molecular forces such as the CH/O and OH/π interaction. The CH/π interaction is a kind of hydrogen bond operating between a soft acid CH and a soft base π-system (double and triple bonds, C6 and C5 aromatic rings, heteroaromatics, convex surfaces of fullerenes and nanotubes). The consequences of CH/π hydrogen bonds in supramolecular chemistry are reviewed on grounds of recent crystallographic findings and database analyses. The topics include intramolecular interactions, crystal packing (organic and organometallic compounds), host/guest complexes (cavity-type inclusion compounds of cyclodextrins and synthetic macrocyclic hosts such as calixarenes, catenanes, rotaxanes and pseudorotaxanes), lattice-inclusion type clathrates (including liquid crystals, porphyrin derivatives, cyclopentadienyl compounds and C60 fullerenes), enantioselective clathrate formation, catalytic enantioface discriminating reactions and solid-state photoreaction. The implications of the CH/π concept for crystal engineering and drug design are evident.

CH/π hydrogen bonds in crystals

Analysis of the molecular packing in over 200 tetraarylporphyrin-based lattice clathrates reveals a strong conservation of host structure. In most cases, formation of porphyrin-based clathrates can be viewed as arising from intercalation of guest molecules into pure host materials. Several modes of intercalation are detected, and characteristic of intercalate structures, staging is observed. Intercalate formation accounts for the relative insensitivity of the host structure to the nature and size of the guest species. The structural conservation observed in this large class of materials facilitates rational modification of the host lattice. Crystallographic data are provided for 75 new porphyrin-based clathrates

Porphyrin sponges: conservative of host structure in over 200 porphyrin-based lattice clathrates

Hexanuclear Manganese(III) Single-Molecule Magnets

The reaction between oxide-centered, triangular [MnIII3O(O2CR)6(py)3](ClO4) (R = Me (1), Et (2), Ph (3)) compounds and methyl 2-pyridyl ketone oxime (mpkoH) affords a new family of Mn/carboxylato/oximato complexes, [MnIII3O(O2CR)3(mpko)3](ClO4) [R = Me (4), Et (5), and Ph (6)]. As in 1−3, the cations of 4−6 contain an [MnIII3(μ3-O)]7+ triangular core, but with each Mn2 edge now bridged by an η1:η1:μ-RCO2- and an η1:η1:η1:μ-mpko- group. The tridentate binding mode of the latter causes a buckling of the formerly planar [MnIII3(μ3-O)]7+ core, resulting in a relative twisting of the three MnIII octahedra and the central O2- ion now lying ∼0.3 A above the Mn3 plane. This structural distortion leads to ferromagnetic exchange interactions within the molecule and a resulting S = 6 ground state. Fits of dc magnetization data for 4−6 collected in the 1.8−10.0 K and 10−70 kG ranges confirmed S = 6 ground states, and gave the following D and g values:  −0.34 cm-1 and 1.92 for 4, −0.34 cm-1 and 1.93 for 5, and −0.35 c...

"Switching on" the properties of single-molecule magnetism in triangular manganese(III) complexes.

Structural, magnetic, and EPR studies of diaquatetrakis({mu}-acetato)dicopper(II) have provided important insight into the magnetic interaction phenomenon in polynuclear species involving 3d ions. This compound may be considered at the archetype of the exchange-coupled copper(II) dimers. Until now, no compound of the same nature involving lanthanide(III) ions had been reported, and the factors determining the sign and the magnitude of the magnetic interaction between lanthanide(III) ions are far from being well understood. Herein the authors report on the synthesis, the structure and the magnetic properties of two lanthanide(III) dimers, namely [Ln{sub 2}(CH{sub 3}CO{sub 2}){sub 6-} (phen){sub 2}] with phen = o-phenanthroline and Ln = Ce (1) and Gd (2).

Molecular structure and magnetic properties of acetato-bridged lanthanide(iii) dimers

Copper(II) complexes with the non-steroidal antiinflammatory drug mefenamic acid in the presence of aqua or nitrogen donor heterocyclic ligands (2,2′-bipyridine, 1,10-phenanthroline, 2,2′-bipyridylamine or pyridine) have been synthesized and characterized. The crystal structures of [(2,2′-bipyridine)bis(mefenamato)copper(II)], 2, [(2,2′-bipyridylamine)bis(mefenamato)copper(II)], 4, and [bis(pyridine)bis(methanol)bis(mefenamato)copper(II)], 5, have been determined by X-ray crystallography. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes can bind to CT DNA and [bis(aqua)tetrakis(mefenamato)dicopper(II)] exhibits the highest binding constant to CT DNA. The cyclic voltammograms of the complexes in the presence of CT DNA solution have shown that the complexes can bind to CT DNA by the intercalative binding mode verified also by DNA solution viscosity measurements. Competitive studies with ethidium bromide (EB) indicate that the complexes can displace the DNA-bound EB suggesting strong competition with EB. Mefenamic acid and its complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values. All the compounds have been tested for their antioxidant and free radical scavenging activity as well as for their in vitro inhibitory activity against soybean lipoxygenase showing significant activity.

Aris Terzis

Papers

Porphyrin sponges: conservative of host structure in over 200 porphyrin-based lattice clathrates

Hexanuclear Manganese(III) Single-Molecule Magnets

"Switching on" the properties of single-molecule magnetism in triangular manganese(III) complexes.

Molecular structure and magnetic properties of acetato-bridged lanthanide(iii) dimers

Non-steroidal antiinflammatory drug–copper(II) complexes: Structure and biological perspectives