Inorganic Chemistry Communications (v.82, #C)

Contents List (iii-vii).

Synthesis and structure of an unprecedented meso-helixes dominated by bivanadyl-capped Keggin POMs by Peipei Zhu; Ning Sheng; Guangjun Liu; Jingquan Sha; Guangchang Shu (1-5).
A new bivanadyl-capped Keggin polyoxometalates based hybrid containing the left- and right-handed helical chains, [Cu12(trz)8][PMo7 VIMo5 VO40(VO)2]·H2O (1) (trz = 1,2,3-triazole), has been hydrothermally synthesized and structurally characterized by routine techniques. It is interesting that the left- and right-handed metal-organic helical chain are constructed from the rigid [Cu5(trz)4] subunits with the same structure but different coordination directions, which is induced and stabilized by [PMo12O40(VO)2]4 − polyoxoanions. Note that the [PMo12O40(VO)2]4 − polyoxoanions link with fourteen Cu ions in the new compound, represents the highest linking number of Keggin POM clusters to date, and dominates to the formation of helical structures. In addition, the electrochemical properties of the new compound have been investigated.A new POMCPs with meso-helix was isolated based on the rigid [Cu5(trz)4] subunits with the same structure but different coordination directions, which is dominated by the highest linked [PMo12O40(VO)2]4 − polyoxoanions.Display Omitted
Keywords: Polyoxometalates; Vanadyl-cap; Helix; Copper; Electrochemical property;

Irreversible solid-state conversion of pencil shaped Na coordination polymer nanorods, prepared by sonochemical procedure, to nanoparticles of corrugated tape silver polymer has been observed upon mechanochemical reaction of compound [Na(μ2-Hdcpa)(μ3-dcpa)]n (1), [Hdcpa = 2,4-dichlorophenoxyacetic acid] with AgNO3. These nanostructures were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), IR spectroscopy and elemental analyses. Thermal stability of these samples was also studied by thermo gravimetric (TG) and differential thermal analyses (DTA).Irreversible solid-state conversion of Na coordination polymer nanorods with rarely seen pencil shaped structure, prepared by sonochemical procedure, to nanoparticles of corrugated tape silver polymer has been observed upon mechanochemical reaction of compound [Na(μ2-Hdcpa)(μ3-dcpa)]n (1), [Hdcpa = 2,4-dichlorophenoxyacetic acid] with AgNO3.Display Omitted
Keywords: Solid-state; Mechanochemical; Nanorods; Nanoparticles; Coordination polymer;

The N-phenylpyridin-2-ylmethanimine ligand, HL reacts with NiCl2·6H2O to afford a water soluble nickel(II) complex, [Ni(HL)2Cl2] 1. Electrochemical studies exhibit that this complex acts as an electrocatalyst for water reduction to hydrogen from a neutral water (pH 7.0) with a TOF of 970.45 mol of hydrogen per mole of catalyst per hour at an OP of 837.6 mV. This can be attributed to the ligand HL, that coordinates through four nitrogen atoms to the nickel center and can stabilize low oxidation state of nickel well.Display Omitted
Keywords: Nickel(II) complex; Molecular electrocatalyst; Water reduction; Hydrogen evolution;

Two new manganese azametallacrowns [Mn6(L)6(OH)6]·(DMF)3 and [Mn4(L)4(OH)4]·(H2O)·(Py)3 (H2L = 2-[5-Pyridin-2-yl-1-H-pyrazol-3-yl]-phenol) with aza18-MC-6 and aza12-MC-4 structural motifs were obtained and characterized by X-ray single crystal diffraction, element analysis, IR and XRD. The magnetic studies reveal the ferromagnetic interactions and field-dependent slow magnetization relaxation in aza18-MC-6, as well as the dominant antiferromagnetic coupling in aza12-MC-4.Two novel manganese complexes aza18-MC-6 and aza12-MC-4 were synthesized, through the new phenolic pyrazole (2-[5-Pyridin-2-yl-1-H-pyrazol-3-yl]-ph-enol, H2L) ligand. Magnetic studies show that aza18-MC-6 exhibits the domain ferromagnetic interactions while aza12-MC-4 displays antiferromagnetic interactions.Display Omitted
Keywords: Phenolic pyrazoles ligand; Multimanganese; Azametallacrown structures; SMM;

Achieving low temperature formaldehyde oxidation: A case study of NaBH4 reduced cobalt oxide nanowires by Yuxin Chen; Yuhang Guo; Hanxi Hu; Shuxian Wang; Ying Lin; Yongchao Huang (20-23).
Oxygen vacancies enable the formation of reactive oxygen species (O2), which can react with the HCHO absorbed at the catalysts surfaces. As a result, the Co3O4 nanowires with surface oxygen vacancies demonstrated superior catalytic performance for HCHO oxidation and exhibited excellent stability in long-term test.Display Omitted
Keywords: Co3O4; Oxygen vacancy; HCHO removal; Reactive oxygen species; NaBH4 reduction;

An uncommon 3D Co5-cluster-based metal-organic framework: Synthesis, structure and magnetism by Yu Wu; Bao-Hong Li; Jian-Qiang Liu; Bin Xie; Hiroshi Sakiyama; Stuart R. Batten (24-26).
A highly connected metal–organic framework (MOF), namely, [Co53-OH)2(iapt)4(4,4′-bipy)0.5(H2O)·CH3CN·3H2O] (1) (H2iapt = 5-aminoisophthalic acid and 4,4′-bipy = 4,4′-bipyridine), is reported. 1 shows a complicated pentanodal 4,4,4,4,13-c 3D net with (43)(43)(43)(43)(420·514·623·78·813) topology based on an uncommon Co5 cluster. The magnetic analysis reveals antiferromagnetic interactions in 1, and both the local spin–orbit coupling of octahedral Co(II) ions and the antiferromagnetic interactions are the primary factors in the magnetic behaviour.A complicated pentanodal 4,4,4,4,13-c 3D net topology based on an uncommon Co5 cluster has been reported. It shows a local spin–orbit coupling of octahedral Co(II) ions and has the antiferromagnetic interactions in the magnetic behaviour.Display Omitted
Keywords: Magnetism; High connection; Cluster; Co(II)-MOF;

Visible-light photolysis of corrole-manganese(IV) nitrites to generate corrole-manganese(V)-oxo complexes by Ngo Fung Lee; Jonathan Malone; Haleh Jeddi; Ka Wai Kwong; Rui Zhang (27-30).
Photolysis of highly photo-labile corrole-manganese(IV) nitrites by visible light was studied in three corrole systems with different electronic environments. As observed in all three systems, homolytic cleavage of O―N bond of nitrite ligand resulted in one-electron photo-oxidation to generate manganese(V)-oxo corroles, as determined by their distinct UV–vis spectra and kinetic behaviors. The spectral and kinetic results are rationalized by a multiple oxidation model, where the electron-demand MnV-oxo species may serve as direct two-electron oxidant for oxygen atom transfer reactions and less electron-demand systems undergo a disproportionation reaction to form a putative manganese(VI)-oxo corrole as the true oxidant.Display Omitted
Keywords: Manganese(V)-oxo; Corroles; Visible light; Oxidation; Kinetics;

The complex Cu(I)(PPh3)2(oxinate) with oxine = 8-quinolinole is luminescent under ambient conditions. In the solid state it shows an emission which originates from the lowest-energy oxinate ILCT state. It consists of a fluorescence and a phosphorescence. In solution saturated with argon, a single broad emission band appears which seems to be composed of a more intense fluorescence and a much weaker phosphorescence at longer wavelength. If this solution is saturated with air, the complete emission band becomes less intense. This is quite surprising, since the oxinate ILCT fluorescence of other oxinate complexes is not quenched by oxygen. It is conceivable that the fluorescence largely consists of a delayed fluorescence. When the emitting triplet is depopulated by a thermally activated transition to the fluorescent singlet, both emissions, the delayed fluorescence and the phosphorescence, may undergo a luminescence quenching. For a simple comparison, the photoluminescence of Ag(PPh3)2(oxinate) was also briefly examined. The absorption and emission spectra of this silver complex in solution at r.t. resemble those of the copper complex.Display Omitted
Keywords: Luminescence; Fluorescence; Phosphorescence; Cu(I) complexes Ag(I) complexes; 8-Quinolinolate complexes; Luminescence quenching by oxygen;

A rod-spacer mixed ligands MOF [Mn3(HCOO)2(D-cam)2(DMF)2]n as coating material for gas chromatography capillary column by Dan-Dan Zheng; Yan Zhang; Li Wang; Mohamedally Kurmoo; Ming-Hua Zeng (34-38).
The interest in metal-organic frameworks (MOFs) is rapidly expanding because of their fascinating architectures and intriguing topologies which allowed for potential applications in gas storage, separation, heterogeneous catalysis, and several other areas. As suitable chromatographic separation media, several MOFs have been employed as stationary phase for gas chromatography and high-performance liquid chromatography. In this work we report the use of a mixed ligands rod-spacer MOF [Mn3(HCOO)2(D-cam)2(DMF)2]n as coating material for capillary column of gas chromatographic separation of a series of biochemical important compounds having linear alkyl hydrocarbon (aldehyde, alcohol and ester), aromatic hydrocarbon with two phenyls (ether, ester and ester with alcohol) and aromatic hydrocarbon (ester, ester with amino and two esters). The mixture of functional ligands, good thermal and chemical stabilities and host-guest interaction sites of the MOF are attributes to the good efficiency in gas chromatographic separation.This work explores the use of the mixed ligands rod-spacer MOF [Mn3(HCOO)2(D-cam)2(DMF)2]n as coating material in the fabrication of capillary column for gas chromatographic separation of a series of biochemical important compounds with close related molecular structures, chemical and physical properties.Display Omitted
Keywords: MOF; Gas chromatography; Stationary phase; Separation;

A cobalt(II) compound, [CoII(terpy)2](TCNQ)4·3DMF·0.5H2O (1; terpy = 2,2′;6′,2″-terpyridine, TCNQ = 7,7′,8,8′-tetracyanoquinodimethane), was found to show incomplete spin-crossover properties in the cobalt(II) complex and semiconducting properties in the quasi one-dimensional packed TCNQ• δ − (0 < δ < 1) radical anions. Single-crystal structures characterized at different temperatures demonstrated non-integer charge distribution among TCNQ radicals. Moreover, electric conductivity measurements revealed that 1 act as semiconductor at 300 K (3.3 × 10− 4  S cm− 1). The coexistence of spin crossover and electric conductivity in one system will pave the way to study the interactions of such different properties and for the implementation of multifunctional materials.A bifunctional cobalt(II) compound, [CoII(terpy)2](TCNQ)4·3DMF·0.5H2O (terpy = 2,2′;6′,2″-terpyridine), shows incomplete spin-crossover properties in the cobalt (II) complex and semiconducting properties in the quasi one-dimensional packed TCNQ• δ − radical anions.Display Omitted
Keywords: Spin-crossover; Semiconductor;

Orientation control of anchored molecules on metal-oxide substrates by Ichiro Imae; Masaki Tsukimori; Takumi Fujimoto; Kazuki Tsukiyama; Yutaka Harima (44-47).
In order to develop a new method to introduce the oriented molecular layer onto the metal-oxide surface, a novel liquid crystalline compound having two chlorosilyl groups at both terminals of alkyl chains (LC-Si) has been synthesized. LC-Si showed a liquid crystalline phase and could be oriented in the in-plane direction by a rubbing treatment. The oriented LC-Si was transferred to the surface of metal-oxide substrate. Atomic-force microscopy showed an ordered structure reflecting the in-plane orientation of a liquid crystalline compound.Display Omitted
Keywords: Liquid crystalline compound; Silane-coupling agent; In-plane orientation;

Exploring the synthesis and metal complexation behavior of mono and bis substituted hexaazamacrocyclic cage derivatives by Vincent Jamier; Eskender Mume; Cyril Papamicaël; Suzanne V. Smith (48-51).
Keywords: Complexation study; Diamsar derivatives; SarAr; Cage ligands; Metal ion encapsulation;

Syntheses and characterisation of novel N/O trispirocyclic cyclotriphosphazenes as ligands for endotopic metal-binding complexes by Kazumasa Kajiyama; Junpei Iwanami; Yoko Fukushima; Yuki Takahashi; Hidetaka Yuge (52-56).
Novel cis,trans,trans and cis,cis,cis N/O trispirocyclic cyclotriphosphazenes, ctt-4 and all-cis- 4, were synthesised by the reaction of hexachlorocyclotriphosphazene, N3P3Cl6 (1), with 2-(1H-pyrazol-3-yl)phenol 2 in the presence of base. The reactions of ctt-4 and all-cis- 4 with copper(I) iodide afforded binuclear complex 5 and mononuclear complex 6, respectively. All new cyclotriphosphazenes were characterised by NMR spectroscopy and the complexes 5 and 6 were also characterised by single-crystal X-ray structural analysis.Display Omitted
Keywords: Trispirocyclic cyclotriphosphazene; Tripodal tridentate ligand; Copper(I); Crystal structure;

A new (1D + 3D) polyoxometalate-based metal-organic pseudo-rotaxane framework by Shaobin Li; Li Zhang; Jianxin Wang; Xiaozhou Zhang; Yujie Hu; Yan Yu; Xiuying Yang; Jingyu Zhang (57-60).
A new compound, [CuI(bib)]2[CuII(bib)2(β-Mo8O26)]∙4H2O (1) (bib = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene), has been synthesized under the hydrothermal condition and characterized by elemental analysis, TG, EDS, IR, XRD and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a complicated (1D + 3D) metal-organic pseudo-rotaxane framework (MOPRF). This fashion is rare in the previous reports on pseudo-rotaxane structure, namely, one “loop” encircles two “strings” rather than a single one. Furthermore, electrochemical studies show that 1 has good electrocatalytic activity toward oxidation of biologic molecule dopamine (DA).A new (1D + 3D) polyoxometalate-based pseudo-rotaxane framework has been synthesized and structurally characterized. Compound 1 shows a good electrocatalytic activity toward oxidation of biologic molecule dopamine.Display Omitted
Keywords: Polyoxometalates; Pseudo-rotaxane frameworks; Coordination polymer; Electrocatalytic property;

By employment of the mixed-ligand strategy, a rare uninodal 9-connected metal-organic framework {[Co6(OH)2(H2O)4(ina)2(cpt)7](NO3)(DMA)4(EtOH)11}n (1, Hina = isonicotinic acid, Hcpt = 4-(4-carboxyl- phenyl)-1,2,4-triazole, DMA =  N,N-dimethylacetamide) has been successfully obtained and structurally characterized. The single-crystal X-ray diffraction studies indicate that the framework of 1 is composed of linear trinuclear {Co3(OH)} clusters that extended by two types of linear bifunctional organic ligands to afford a 3D framework, which could be rationalized as a vnf network with the short Schläfli symbol of 39.420.57. To the best of our knowledge, 1 is the first example of 9-connected MOFs showing such a type of topological net. In addition, the magnetic properties of 1 have also been investigated.A rare uninodal 9-connected metal-organic framework has been successfully synthesized by employing a linear trinuclear {Co3(OH)} unit and two bifunctional organic ligands, which demonstrates a rare vnf net with the short Schläfli symbol of 39.420.57. Furthermore, the magnetic properties of this MOF have also been investigated.Display Omitted
Keywords: High-connected MOF; Trinuclear co unit; vnf-type topology; Magnetic property;

Wettability switchable metal-organic framework membranes for pervaporation of water/ethanol mixtures by Sasa Wang; Zixi Kang; Ben Xu; Lili Fan; Guoqing Li; Ling Wen; Xuelian Xin; Zhenyu Xiao; Jia Pang; Xinxin Du; Daofeng Sun (64-67).
To evaluate the effect of MOF surface wettability for the purification of ethanol from water/ethanol mixtures, the hydrophilic Ni2(l-asp)2bipy membrane is switched to hydrophobic Ni2(l-asp)2bipy@PDMS membrane via vapor deposition of PDMS. The PDMS coating can improve the hydrothermal stability of MOF membranes. The stable Ni2(l-asp)2bipy membrane exhibits a high flux of H2O and acceptable separation factor. The pervaporation studies based on the both two membranes provide insight into the effect of surface wettability on the bio-ethanol purification performance.The hydrophilic Ni2(l-asp)2bipy membrane is switched to hydrophobic Ni2(l-asp)2bipy@PDMS membrane via a vapor deposition of PDMS and the both two membranes are applied to the pervaporation process. The stable Ni2(l-asp)2bipy membrane exhibit a high flux of H2O. The pervaporation studies based on the two membranes provide insight into the effect of surface wettability on the bio-ethanol purification performance.Display Omitted
Keywords: Metal-organic framework; Membrane; Post-deposing; Water/ethanol separation;

PVP-assisted synthesis of monodisperse UiO-66 crystals with tunable sizes by Yali Li; Yajing Zhao; Rui Zhang; Guang Lu (68-71).
A polyvinylpyrrolidone (PVP)-assisted synthesis method was reported to prepare monodisperse UiO-66 octahedral crystals with tunable sizes. In this acetic acid/PVP co-modulated synthesis system, the relatively weak coordination of PVP to Zr(IV) played an important role in manipulating the sizes of UiO-66 crystals instead of their shapes. With the optimized PVP concentrations, sizes of the monodisperse UiO-66 crystals could be effectively tuned from ~ 1900 nm to ~ 700 nm. These uniform MOF crystals could be assembled into monolayers on water surface and further transferred onto a solid substrate to yield MOF films with preferential orientation and controlled thicknesses.A polyvinylpyrrolidone (PVP)-assisted synthesis method was reported to prepare monodisperse UiO-66 octahedral crystals with tunable sizes.Display Omitted
Keywords: Microporous materials; Metal-organic framework; UiO-66; Monodisperse crystals; Modulation synthesis;