A sandwiched Co4-added polyoxometalate for efficient visible light-driven hydrogen evolution.

A new Co4-added polyoxometalate (CoAP) Cs4[(Co(H2O)5)2{(µ2-Co(H2O)4)2Co4(H2O)2(B-α-GeW9O34)2}]·6H2O (1) has been made using a lacunary directing strategy under hydrothermal conditions. Single-crystal X-ray diffraction analysis demonstrated that 1 is a one-dimensional (1D) chain, in which CoAP is linked by cobalt-oxygen octahedra to form a 1D structure with excellent chemical stability. The visible light-driven H2 evolution test demonstrated that 1 has high activity, with an H2 evolution rate of 1485.95 µmol h-1 g-1. PXRD and FT-IR tests demonstrated that compound 1 exhibits excellent heterogeneous catalytic stability.

Polar Molecules Regulating the Regio- and Stereoselectivity of Polymerization of Conjugated Dienes Catalyzed by CGC-Type Rare-Earth Metal Catalysts.

Herein, a concise, effective, and scalable strategy is reported that the introduction of polar molecules (PMs) (e.g., anisole (PhOMe), phenetole (PhOEt), 2-methoxynaphthalene (NaphOMe), thioanisole (PhSMe), and N,N-dimethylaniline (PhNMe2)) as continuously coordinated neutral ligand of cationic active species in situ generated from the constrain-geometry-configuration-type rare-earth metal complexes A-F/AliBu3/[Ph3C][B(C6F5)4] ternary systems can easily switch the regio- and stereoselectivity of the polymerization of conjugated dienes (CDs, including 2-subsituted CDs such as isoprene (IP) and myrcene (MY), 1,2-disubstituted CD ocimene (OC), and 1-substituted polar CD 1-(para-methoxyphenyl)-1,3-butadiene (p-MOPB)) from poor selectivities to high selectivities (for IP and MY: 3,4-selectivity up to 99%; for OC: trans-1,2-selectivity up to 93% (mm up to 90%); for p-MOPB: 3,4-syndioselectivity (3,4- up to 99%, rrrr up to 96%)). DFT calculations explain the continuous coordination roles of PMs on the regulation of the regio- and stereoselectivity of the polymerization of CDs. In comparison with the traditional strategies, this strategy by adding some common PMs is easier and more convenient, decreasing the synthetic cost and complex operation of new metal catalyst and cocatalyst. Such regio- and stereoselective regulation method by using PMs is not reported for the coordination polymerization of olefins catalyzed by rare-earth metal and early transition metal complexes.

Three new aluminoborates: from 1D tube to 3D framework.

Three new aluminoborates (ABOs) KCs[Al{B5O9(OH)}{BO(OH)2} (1), K0.5Cs[Al{B5O10}1/2{BO2(OH)}] (2), and Cs1.5[Al{B5O10}1/2{BO2(OH)}] (3) have been made under solvothermal conditions. 1 features a 1D tube constructed by the alternation of [B5O9(OH)]4- clusters and AlO4 units, onto which the [BO(OH)2]- triangles are grafted. To further construct higher dimensional structures based on the structure 1, solvents were adjusted for high basicity, resulting in the formations of the 3D ABO frameworks 2 and 3. 2 and 3 are isostructural and built from [B5O10]5- clusters, AlO4 tetrahedra and [BO2(OH)]2- triangles, in which [B5O10]5- clusters are bridged by AlO4 tetrahedra to produce a 2D ABO layer with 14-membered ring (MR) windows, and the [BO2(OH)]2- triangles act as the linkers to bridge the adjacent ABO layers to form 3D ABO frameworks containing eight types of channels. UV-vis diffuse reflectance spectra indicate that 1, 2, and 3 have potential applications in deep ultraviolet (DUV) regions.

Na1.5Cs0.5[Al{BO3}{B9O15(OH)3}1/3]: An Acentric Layered Aluminoborate with Nonlinear-Optical Properties.

An acentric aluminoborate (ABO), Na1.5Cs0.5[Al{BO3}{B9O15(OH)3}1/3] (1), has been made under solvothermal conditions. The alternations of AlO4 tetrahedra and BO3 triangles first build up the 2D ABO layer with 6-MR (membered-ring) windows. The fanlike B9O15(OH)3 cluster adorns the layer through Al-O-B linkages, producing a pair of unclosed channels with 7-MR aperture on the lateral side of the layers. The novel B9O15(OH)3 cluster represents the largest oxoboron cluster in the acentric ABO family. 1 not only shows a moderate second-harmonic-generation response of 1.2 times that of potassium dihydrogen phosphate but also has a short cutoff edge below 200 nm, indicating its potential applications in deep-UV regions.

Two New Aluminoborates with 3D Porous-Layered Frameworks.

Two new aluminoborates, NaKCs[AlB7O13(OH)]·H2O (1) and K4Na5[AlB7O13(OH)]3·5H2O (2), have been hydro(solvo)thermally made with mixed alkali metal cationic templates. Both 1 and 2 crystallize in the monoclinic space group P21/n and contain similar units of [B7O13(OH)]6- cluster and AlO4 tetrahedra. The [B7O13(OH)]6- cluster is composed of three classical B3O3 rings by vertex sharing, of which two of them connect with AlO4 tetrahedra to constitute monolayers, and one provides an O atom as a bridging unit to link two oppositely orientated monolayers by Al-O bonds to form 3D porous-layered frameworks with 8-MR channels. UV-Vis diffuse reflectance spectra indicate that both 1 and 2 exhibit short deep-UV cutoff edges below 190 nm, revealing that they have potential applications in deep-UV regions.

Two New Nonaborates with {B9} Cluster Open-Frameworks and Short Cutoff Edges.

Two new nonaborates, Na2Ba0.5[B9O15]·H2O (1) and Na4Ca1.5[B9O16(OH)2] (2), have been solvothermally made with mixed alkali and alkaline-earth metal cationic templates. 1 and 2 are constructed by two different types of nonaborate clusters. In 1, the [B9O19]11- cluster is composed of three corner-sharing [B3O7]5- clusters, of which two of them interconnect to the 1D B3O7-based chains and are further bridged to the 3D framework with 7 types of 10-MR channels by another [B3O7]5- bridging cluster. The [B9O18(OH)2]11- cluster in 2 is made of four BO4-sharing [B3O8]7- clusters. As a 4-connected node, the interconnections of [B9O18(OH)2]11- construct the unpreceded 2D layer with large 14-MR windows, which are further joined by H-bonds to the 3D supramolecular framework. UV-Vis absorption spectra reveal that both 1 and 2 have short cutoff edges below 190 nm, exhibiting bandgaps of 6.31 and 6.39 eV, respectively, indicating their potential applications in deep UV (DUV) regions.

Designed Syntheses of Three {Ni6PW9}-Based Polyoxometalates, from Isolated Cluster to Cluster-Organic Helical Chain.

Three new hexa-Ni-substituted Keggin-type polyoxometalates (POMs), [Ni6(OH)3- (DACH)3(H2O)6(PW9O34)]·31H2O (1), [Ni(DACH)2][Ni6(OH)3(DACH)3(HMIP)2(H2O)2(PW9O34)]·56 H2O (2), and [Ni(DACH)2][Ni6(OH)3(DACH)2(AP)(H2O)5(PW9O34)]·2H2O (3) (DACH = 1,2-Diami- nocyclohexane, MIP = 5-Methylisophthalate, AP = Adipate) were successfully made in the presence of DACH under hydrothermal conditions. 1 is an isolated hexa-Ni-substituted Keggin unit decorated by DACH. In order to further construct POM cluster-organic frameworks (POMCOFs) on the basis of 1, by analyzing the steric hindrances and orientations of the POM units, the rigid HMIP and flexible AP ligands were successively incorporated, and another anionic monomeric POM 2 and the new 1D POM cluster organic chain (POMCOC) 3 were obtained. HMIP ligand still acts as a decorating group on the Ni6 core of 2 but results in the different spatial arrangement of the {Ni6PW9} units. AP ligands in 3 successfully bridge adjacent isolated POM cluster units to 1D POMCOC with left-hand helices. The AP in 3 is the longest aliphatic carboxylic acid ligand in POMs, and the 1D POM cluster-AP helical chain represents the first 1D POMCOC with a helical feature.

Two layered galloborates from centric to acentric structures: syntheses and NLO properties.

Two layered galloborates (GBOs), Na3GaB4O9 (1) and Na5Ga[B7O12(OH)]2·2B(OH)3 (2), have been solvothermally made. 1 exhibits an unprecedented layer built by GaO4 tetrahedra and B4O9 clusters. 2 was made by raising the ratio of B/Ga and the reaction temperature of 1, featuring a 2D acentric layer built by GaO4 groups and B7O13(OH) clusters. 2 shows the highest second-harmonic generation (SHG) response of 4.6 times that of KDP (KH2PO4) among main group metal borates (MBOs).

Chiral {Ni6PW9} Cluster-Organic Framework: Synthesis, Structure, and Properties.

A chiral three-dimensional polyoxometalate cluster-organic framework (POMCOF) H3[(btc)Ni6(µ3-OH)3(H2O)5(B-α-PW9O34)]·17H2O (1, btc = 1,2,4-benzenetricarboxylate) has been made under hydrothermal conditions in the absence of amine or chiral starting reagents. 1 shows high stability in CH3CN/DMF (1:3), acidic, and basic solutions with the pH ranging from 2 to 12 for 5 days. The UV-vis reflectance spectra and Mott-Schottky measurements reveal that 1 could be a suitable catalyst for photocatalysis. Visible-light-driven H2 evolution studies have demonstrated that 1 is an ecofriendly, efficient, and recyclable catalyst with a H2 evolution rate of 1058.24 µmol h-1g-1. Nonlinear optical (NLO) measurement reveals that 1 exhibits a second-harmonic generation (SHG) response of about 1.4 times that of KH2PO4 (KDP), indicating that 1 is a potential NLO material as well.

Four Inorganic-Organic Hybrid Borates: From 2D Layers to 3D Oxoboron Cluster Organic Frameworks.

Four inorganic-organic hybrid borates, K[B6O9(OH)(en)]·H2O (1, en = ethylenediamine), K[B6O9(OH)(1,3-dap)]·H2O (2, 1,3-dap = 1,3-diaminopropane), K[B6O9(OH)(1,6-dah)0.5]·H2O (3, 1,6-dah = 1,6-diaminlhexane) and [(1,3-dap)Cd@B5O8(OH)]·0.5H2O (4), were made under solvothermal conditions. 1 and 2 are isostructural and feature a 2D layer built by B6O9(OH) clusters and modified by en and 1,3-dap via B-N-C linkages. By replacing en and 1,3-dap with longer and more flexible 1,6-dah, a new type of oxoboron cluster organic framework 3 was obtained, which was composed of the same B6O9(OH) cluster layers as in 1 and 2 and 1,6-dah linkers. By replacing alkali metal K with transition metal Cd under similar synthetic conditions, another type of oxoboron cluster organic framework 4 was made in which the Cd-centered wheel cluster layers and 1,3-dap linkers were connected via Cd-N-C linkages.

K2 Na3 [{B6 O10 (OH)}{B3 O4 (OH)3 }] ⋠H2 O: A Layered Borate Built by Mixed Oxoboron Clusters with Nonlinear-Optical Property.

A new acentric borate, K2 Na3 [{B6 O10 (OH)}-{B3 O4 (OH)3 }] ⋅ H2 O (1) has been made under solvothermal condition. 1 has layered structure made by B6 O13 (OH)-based chains and B3 O5 (OH)3 -bridging clusters. Second-harmonic generation (SHG) measurements reveal that 1 is a phase-matchable nonlinear optical (NLO) material, showing the SHG signal intensity of 1.8 times that of KDP (KH2 PO4 ). Besides, UV-Vis diffuse reflectance spectrum shows that 1 has the short deep UV (DUV) absorption cutoff edge of 198 nm. Thermogravimetric analysis reveals it has good thermal stability. Also 1 represents firstly mixed oxoboron clusters-made 2D layered borate with NLO property.

Two Chiral Metal Complex Templated Aluminoborates Constructed from Three Types of Oxoboron Clusters.

The two acentric aluminoborates (ABOs) [M(dap)3]2{Al[B5O7(OH)3][B5O8(OH)2][B6O9(OH)2]} (M and dap represent Co(1)/Ni(2) and 1,2-diaminopropane, respectively) templated by chiral metal complexes (CMCs) have been solvothermally synthesized. The isostructural 1 and 2 crystallize in the chiral space group P21. Both feature unprecedented 2D wavelike layers built by three kinds of oxoboron (B-O) clusters ([B5O7(OH)3]2-, [B5O8(OH)2]3-, and [B6O9(OH)2]2-) and AlO4 tetrahedra. In the frameworks of 1 and 2, AlO4 and [B6O9(OH)2]2- units are strictly alternating into 1D chains. Further, [B5O8(OH)2]3- clusters link adjacent chains to form 2D wavelike layers. In addition, the [B5O7(OH)3]2- units as the hanging clusters are supported on two sides of the wavelike layers through AlO4 groups, resulting in the first example of a wavelike layer ABO composed of three kinds of B-O clusters and four types of channels. 1 and 2 display second-harmonic generation (SHG) signals about ∼1.3 and ∼0.93 times that of KH2PO4 (KDP) and belong to the class of wide-band-gap semiconductors.

Three Inorganic-Organic Hybrid Gallo-/Alumino-Borates with Porous-Layered Structures Containing [MB4O10(OH)] (M = Al/Ga) Cluster Units.

Three inorganic-organic hybrid gallo-/alumino-borates [Ga2B7O14(OH)]·H2dah (1, dah = 1,6-diaminohexane), K2[Ga2B7O14(OH)(en)0.5] (2, en = ethylenediamine), and K2[Al2B7O14(OH)(en)0.5]·H2O (3) were synthesized under solvothermal conditions. Compound 1 features a 3D porous-layered structure built by the alternation of [GaB4O10(OH)]6-, [B3O6]3- clusters and GaO4 tetrahedra, in which the novel [GaB4O10(OH)]6- cluster is first observed. Compounds 2 and 3 are isostructural and made by [MB4O10(OH)]6-, [B3O6(en)0.5]3- clusters and MO4 tetrahedra (M = Ga/Al); their 3D porous layers are similar to those of 1 and further bridged by en linkers through the rare B-N-C covalent bonds, resulting in the 3D inorganic-organic hybrid framework. This is the first main-group metal borate with organic molecules participating in the oxoboron frameworks through B-N bonds. Optical diffuse-reflectance spectra reveal that 1, 2, and 3 are potential wide-band-gap semiconductors.

Syntheses and structures of a new 2D layered borate and a novel 3D porous-layered aluminoborate.

Two new layered and porous-layered borates ([H2dap][B7O11(OH)] (1, dap = 1,2-propanediamine) and [H3O]K3.52Na3.48{Al2[B7O13(OH)][B5O10][B3O5]}[CO3] (2)) have been solvothermally made. 1 features a 2D layer made of the [B7O13(OH)]6- cluster, in which H2dap is located in the windows of the layers. The fundamental building block (FBB) [B7O13(OH)]6- cluster in 1 represents a new type of FBB of the hepta-borate family. 2 is a novel aluminoborate with a 3D porous-layered structure formed by three types of oxoboron clusters, [B7O13(OH)]6-, [B5O10]5- and [B3O7]5-, respectively. The strict alternation of the different oxoboron clusters and AlO4 tetrahedra leads to the abundant channel systems of the structure. 2 is the first aluminoborate (ABO) containing three types of oxoboron clusters and the first 3D porous-layered ABO with seven types of channels. UV-vis diffuse reflectance spectra reveal that both of them are wide band-gap semiconductors and have potential applications in UV regions.

[Application of a pH feedback-controlled substrate feeding method in glutamic acid fermentation].

A novel method based on pH value was proposed to simplify the substrate feeding method for glutamic acid fermentation. The linear relationship between the consumption amounts of ammonia (x) and that of glucose (y) was established (y = 7.4744x, R2 = 0.9989) which could be used as the ratio of the amount of ammonia and that of glucose in the feeding broth. Thus the concentration of glucose could be controlled through the adjustment of pH automatically. In the glutamic acid fermentation using the pH feedback-controlled glucose feeding method, the glucose concentration in fermentation broth was maintained between 12 and 21 g/L. Compare with the constant glucose concentration feeding method, the glucose conversion rate and glutamic acid productivity increased by 9.06% and 17.5% respectively, when the pH feedback-controlled glucose feeding method was employed, and fermentation period was shorten above 2 h.