An Inorganic Double Helix: Hydrothermal Synthesis, Structure, and Magnetism of Chiral [(CH3)2NH2]K4[V10O10(H2O)2(OH)4(PO4)7]{middle dot}4H2O

Step-by-step strategy from achiral precursors to polyoxometalates-based chiral organic-inorganic hybrids

Using two types of triol ligands, several novel asymmetrically triol-functionalized Anderson organic hybrids have been efficiently synthesized in high purity and good yields via a convenient two-step esterification reaction. These organic-inorganic hybrids are chiral and can be spontaneously resolved with suitable solvents. Their molecular and crystal structures have been confirmed by single-crystal X-ray diffraction studies. Stable solid-state chirality of the corresponding enantiopure crystals has also been confirmed definitively by CD spectra. Interestingly, these organic-inorganic hybrids possess a layer-by-layer structure, forming solvent-accessible nanoscale chiral channels via a 1D infinite helical chain substructure. TGA measurements indicated that the species of the central heteroatoms significantly effects the stability of these compounds.

Lanthanide-supported molybdenum–vanadium oxide clusters: syntheses, structures and catalytic properties

Three new species, originating from β-[Mo₆V₂O₂₆]⁶⁻ polyoxoanion and lanthanides, as heterogeneous catalysts exhibit good catalytic activities toward the cyanosilylation reaction.

Temperature-induced racemic compounds and chiral conglomerates based on polyoxometalates and lanthanides: syntheses, structures and catalytic properties

Four new species, originated from [Co₂Mo₁₀H₄O₃₈]⁶⁻ and lanthanides by adjusting the reaction temperature, are reported, which act as Lewis acid–base catalysts toward the cyanosilylation reaction.

Architectural control of urea in supramolecular 1D strontium vanadium oxide chains

The critical effects of small organic ligands such as urea on the assembly of 1D strontium vanadium oxide chains using the principles of molecular self-assembly are discussed.

Capillary electrochromatographic fast enantioseparation based on a chiral metal-organic framework

Metal-organic frameworks (MOFs) have received great attention because of their unusual properties and fascinating structures in separation sciences. However, to the best of our knowledge, there has been no attempt to utilize chiral MOFs as stationary phases in packed-CEC. Here, a chiral MOF [In3 O(obb)3 (HCO2 )(H2 O)]·solvent (4,4'-oxybisbenzoic acid) was explored as the chiral stationary phase in packed-CEC for separation of chiral compounds and isomers. The fabricated [In3 O(obb)3 (HCO2 )(H2 O)]·solvent packed capillary columns gave fast enantioseparation of (±)-hydrobenzoin, (±)-1-phenyl-1,2-ethanediol, and clenbuterol within 3 min in CEC. Besides, the baseline separations of nitrophenol isomers within 6 min were also achieved. The RSDs for the retention time of run-to-run, day-to-day, and column-to-column reproducibility were 1.51-3.63, 1.83-3.98, and 3.42-5.66%, respectively. These results demonstrate that chiral MOFs are promising for enantioseparation in CEC.

Emerging double helical nanostructures

As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on 'bottom-up' and 'top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

Chirality meets visible-light photocatalysis in a molecular cerium vanadium oxide cluster

The first example of a molecular cerium vanadium oxide photocatalyst is presented. A cerium vanadium oxide cluster, (nBu4N)2[(Ce(dmso)3)2V(IV)V(V)11O33Cl] × 2DMSO (1), was obtained by bottom-up self-assembly. The compound exhibits high visible-light photooxidative activity towards indigo with quantum efficiencies >10%. Initial mechanistic studies of the photooxidation reaction are presented. The structure of compound 1 is based on chiral, C2-symmetric cluster anions and both enantiomers are present in the crystal lattice. Retrosynthetic analysis suggests that chiral building blocks are spontaneously formed by symmetry breaking during self-assembly. The assembly of 1 based on the chiral building blocks is discussed conceptually. Consequences of this assembly mechanism for the development of chiral molecular catalysts and photocatalysts are described.

Versatile coordination modes of bis[5-(2-pyridine-2-yl)-1,2,4-triazole-3-yl]alkanes in Cu(ii) complexes

Nine new mononuclear and polynuclear Cu(ii) complexes containing [5-(2-pyridine-2-yl)-1,2,4-triazole-3-yl]alkanes (H₂Lⁿ, n = 1–4) were synthesized and characterized by various techniques.

Synthesis and characterization of robust three-dimensional chiral metal sulfates

Chiral three-dimensional Mg(ii) and Mn(ii) sulfates have been synthesized, well characterized and studied from first-principles calculations. High temperature X-ray diffraction, thermogravimetric analysis and DFT calculations reveal that the structures of both the compounds remain intact even after the thermal decomposition of the ammonium ion.

The coexistence of interconnected and interweaved double helices in an octamolybdate-based compound: synthesis, structure, and photocatalytic properties

Assembly and photocatalytic properties of an unprecedented helical compound based on polyoxometalates, with the coexistence of both interconnected and interweaved double helices, are reported.

pH-controlled assembly of hybrid architectures based on Anderson-type polyoxometalates and silver coordination units

Three new architectures based on Anderson-type polyoxometalates, (3-H2pya)[(3-Hpya)2Ag][AgAlMo6H6O24]·3H2O 1, HNa2[(3-pya)(3-Hpya)Ag]2[AlMo6H6O24]·8H2O 2 and [(3-Hpya)2Ag][(H2O)2Ag]2[AlMo6H6O24]·2H2O 3 (3-Hpya = 3-(3-pyridyl)acrylic acid), have been synthesized at the different pH values and characterized by elemental analysis, IR spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compound 1 was obtained at lower pH value (2.50), and represents a 3D host-guest compound containing the Ag-3-Hpya coordination complex guest and the 3D [AgAlMo6H6O24](2-) host. The host framework exhibits a 4-connected diamond topology, and is constructed from [AlMo6H6O24](3-) clusters connected by Ag(+) cations. When the pH value was increased slightly, compound 2 was obtained with a 1D chain structure built up of Anderson polyoxoanions, Ag-3-Hpya coordination complexes and binuclear sodium clusters. By further increasing the pH value (3.50), compound 3 was isolated as a 2D network in which [AlMo6H6O24](3-) clusters are linked together by Ag(+) cations and Ag-3-Hpya coordination complexes. Their structural differences reveal that the pH value of the reaction system is the key factor influencing the structure and topology of three compounds. The UV-visible-NIR diffuse reflectivity spectra of 1-3 show that they can be regarded as a wide gap semiconductor. Furthermore, the pyrolysis of 1-3 produces three nanocomposites 1'-3' composed of silver microparticles dispersed in the metal oxides. The photocatalytic properties of 1'-3' have been investigated.

What Stabilizes the LinPn Inorganic Double Helices?

Recently, inorganic double-helical structures based on simple lithium and phosphorus salts have been demonstrated. We have analyzed the nature of bonding in these double helices of LinPn (n = 7-9). Similar to DNA, noncovalent interactions and cooperativity play an important role in stabilizing the inorganic double helices. Cooperativity imparts an additional stabilization of 4.5 to 10.1 kcal/mol per Li-P pair. In addition, the ionicity of Li-P units further augments the stability of these inorganic double-helix structures in contrast with the canonical base pairs in DNA, where noncovalent interactions determine the duplex stability. Unwinding is shown to be unfavorable, and cleavage of a few edge Li-P bonds leads to spontaneous self-healing into the intact double-helix tract.