Synthesis, Crystal Structure and Magnetic Properties of a Coordination Polymer Based on Iron(Ⅱ) Carboxylate Helical Chains [Fe(bpdc)(H_2O)_2]n

A coordination polymer based on iron（II） carboxylate helical chains [Fe（bpdc）（H2O）2]n 1 has been constructed hydrothermally using H2bpdc （H2bpdc = 2,2＇-bipyridine-4,4＇-dicarboxylic acid）, pyridine and FeSO4·7H2O. Its crystal structure reveals that the Fe（Ⅱ） ion adopts a slightly distorted octahedron. The carboxylates of bpdc ligands alternately bridge the Fe（Ⅱ） cations to form 1D infinite helical chains. The Fe···Fe intrachain distance is 4.8246（6） . The adjacent chains are further interlinked by the coordination of bpdc ligands and hydrogen bonding to form a 3D framework. Magnetic studies for complex 1 show weak antiferromagnetic coupling between the Fe（Ⅱ） ions. The best-fit for χM T vs. T with a Hamiltonian∑∑==iBiiHJSi SigHS11 leadsto g = 2.314（4） and J = –0.68（1） cm-1.

Syntheses,Structures,and Photoluminescent Properties of Two Zn(Ⅱ)Coordination Polymers with Helical Chains Structures

Two novel coordination polymers with helical chains, {[Zn（L）（H2O）]·H2O}n（1） and {[Zn（L）（p-bix）]·3.5H2O}n（2）, where H2 L = 5-（4-hydroxypyridinium-1-ylmethyl） isophthalic acid and p-bix = 1,4-bis（imidazol-1-ylmethyl）benzene, have been hydrothermally synthesized, and charac-terized by elemental analysis, powder X-ray diffraction（PXRD）, IR, thermal gravimetric analyses（TGA） and also by single-crystal X-ray diffraction. Both complexes 1 and 2 crystallize inmonoclinic, space group P21/c. Compound 1 displays a two-dimensional（2D） structure with two distinct types of helical chains; 2 shows a layered coordination polymer with two types of helical chains and features an interesting 2D→3D interdigitated architecture. Meanwhile, the luminescent properties of 1 and 2 have also been investigated in detail.

Two New Alkaline Metal Borates with Supramolecular Framework Constructed from 1D{B5}/{B6}Helical Chains

Two new alkaline metal borates containing 1D{B5}/{B6}oxoboron helical chains,namely Na0.5[B5O8(OH)2]0.5[B5O6(OH)2]0.5·0.5H3O(1)and NaKCs[B6O9(OH)3](2)were synthesized under solvothermal conditions.Compound 1 contains the interesting alternative left-and right-handed helical{[B5O8(OH)2][B5O6(OH)2]}2-({B5}-1 and{B5}-2)1D chains and compound 2 possesses the similar[B6O11(OH)3]7-({B6})chains.Their 1D chains are further assembled into 2D layers and 3D supramolecular frameworks through O-H…O hydrogen bonds.In addition,the UV cutoff edge of compounds 1 and 2 is both below 190 nm.

Synthesis,Crystal Structure and Fluorescence Property of the Ag(Ⅰ) Coordination Polymer Constructed by 2D[Ag(1,3-BIP)(PMA)_(0.5)]_n^(n-)Layers and 1D[Ag(1,3-BIP)(H_2O)]_n^(n+) Chains

A new AgO） coordination polymer, {[Ag（1,3-BIP）（H20）][Ag（1,3- BIP）（PMA）0.5.- 4H20}n （PMA = 1,2,4,5-benzenetricarboxylic acid, 1,3-BIP = 1,3-bis（imidazole）propane）, have been synthesized and characterized by single-crystal X-ray diffraction, powder XRD, FTIR, TGA and elemental analysis techniques. The single-crystal X-ray diffraction reveals that the title complex is formed by 1D polymeric cationic chains of [Ag（1,3-BIP）（H2O）]n^n＋ and 2D polymetric anionic layer of [Ag（1,3-BIP）（PMA）0.5]n^n-, which are further linked by intermolecular H-bonding to form a 3D supramolecular framework. In addition, the photoluminescence property of the title complex in the solid state at room temperature was also investigated.

A Novel 3D Twofold Zn(Ⅱ) Coordination Polymer Constructed by Mixed Flexible Ligands:Synthesis,Crystal Structure and Fluorescence Property

A new Zn（Ⅱ） coordination polymer, {[Zn（1,3-bip）（oba）]·0.5H2O}n（1）,1,3-bip =1,3-bis（imidazole）propane, H2oba=4,4？-oxybis（benzoate））, have been synthesized and characterized by single-crystal X-ray diffraction, powder XRD, FTIR, TGA and elemental analysis techniques. The single-crystal X-ray diffraction reveals that complex 1 shows a 3D→3D twofold interpenetrating network that can be described as a 4-connected uninodal net with（65.8） topology. In addition, the photoluminescence property of complex 1 was also investigated at room temperature.

Two Coordination Novel Polymers Based on a Flexible Ligand N,N'-diacetic Acid Imidazolium

{[Cu_3（cis-DAM）_4（OH）_2]·12H_2O}_n 1 and [Ag_3（trans-DAM）_2（NO_3）]_n 2 with a flexible ligand N,NA-diacetic acid imidazolium（HDAM） were synthesized and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic I222 space group with a = 12.033（2）,b = 12.498（3）,c = 14.963（3） A,V = 2250.4（8） A^3,Z = 8,C_7H_（13.5）N_2O_（7.5）Cu_（0.75）,M_r = 293.35,D_c = 1.732 g·cm^-3,F（000） = 1210,GOF = 1.087,the final R（I 〉 2σ（I）） = 0.0521 and w R（all data） = 0.1386. Compound 2 crystallizes in the monoclinic C2/c space group with a = 21.601（4）,b = 8.321（2）,c = 13.589（3） A,β = 126.95（3）°,V = 1951.9（7） A^3,Z = 8,C_7H_7N_（2.5）O_（5.5）Ag_（1.5）,M_r = 375.96,D_c = 2.559 g·cm^-3,F（000） = 1448,GOF = 1.017,R（I 〉 2σ（I）） = 0.0222 and w R（all data） = 0.0633. Compound 1 displays a novel 2D layer,consisting of a couple of left-helical chains with a pitch of 12.498（3） A formed by μ_3-cis-DAM~– ligands and Cu（1） ions,which are stabilized by hydrogen bonding interactions to give a 3D supramolecular framework. As for 2,Ag（1） ions are doubly bridged by trans-DAM~– and NO_3~– to form [Ag（1）_2O_4] chains,which are further connected by Ag（2） and trans-DAM~– to build a 3D framework. Additionally,thermogravimetric analyses,FT-IR spectroscopy,UV-visible spectroscopy,and the fluorescent properties were discussed.

A Phenyl Sulfide Functionalized Luminescent Sensors for Efficient Fe3+ and Cr2O72- Ions Detection

A new complex, {[Cd（BIDPT）（NBA）]}n（1）, was synthesized from the selfassembly of BIDPT（BIDPT = 4,4?-bis（imidazol-l-yl）diphenyl thioether） and H2NBA（H2 NBA = 4,4?-azanediyldibenzoic acid） ligands with Cd（Ⅱ）. 1 was characterized by infrared spectroscopy, powder X-ray diffraction, elemental analysis, and thermogravimetry measurement. 1 crystallizes in monoclinic system, space group P21/c with a = 8.8204（1）, b = 29.835（3）, c = 10.3813（1） ?, β = 96.180（2）°, V = 2730.7（5） ?3, Z = 4, C32H22CdN5O4S, Mr = 685.01, Dc = 1.666 g/cm3, μ = 0.926 mm-1, R = 0.0548 and wR = 0.1528. 1 features a parallel structure with 3-connected hcb network and the adjacent 2 D networks are stacked together via C–H···π interaction to form a 3 D network. Its application in detecting metal cations and inorganic anions was explored. 1 exhibits excellent photoluminescence sensing for Fe3+ and Cr2O72- ions. And the mechanism of quenching is also studied.

Synthesis and Crystal Structure of a New Mn(Ⅱ) Coordination Polymer Based on Asymmetric Semi-rigid V-shaped Dicarboxylate

A novel manganese（Ⅱ） coordination polymer with 2-（4-carboxyphenoxy） benzoic acid （2,4＇-H2oba） and 1,10-phenanthroline （1,10-phen） has been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction, IR and elemental analysis. Compound [Mn（2,4＇-oba）（1,10-phen）] is of monoclinic system, space group P21/n with a = 7.960（1）, b = 15.464（2）, c = 18.703（3）A, β = 99.976（2）°, V = 2267.5（6） A^3, Z = 4, Mr = 491.35, Dc = 1.439 g/cm^3, F（000） = 1004 and μ = 0.623 cm·1. The final R = 0.0419 and wR = 0.0978 for 3444 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that the oba2-ligands adopt a bis（chelating bidentate） mode to link two Mn（Ⅱ） centers to form an infinite 1D helical chain. Furthermore, a 3D supramolecular structure was formed by π-π stacking interactions and hydrogen bonds.

Tellurene:An elemental 2D monolayer material beyond its bulk phases without van der Waals layered structures

Due to the quantum confinement effect,atomically thin two-dimensional(2D)monolayer materials possess distinct characteristics from their corresponding bulk materials,which have received wide attention from science and industry.Among all the 2D materials,elemental 2D materials with the simplest components are most striking.As an emerging group-VIA elemental 2D monolayer material,tellurene exhibits many exciting fundamental properties,such as chemical and mechanical stabilities,bandgap and high carrier mobilities compared to phosphorene,graphene and MoS2,respectively.Besides,in further exploration,it was found that tellurene or tellurene-based device presents excellent thermoelectric properties,piezoelectric properties,quantum Hall effects,and superb optical properties especially nonlinear optics characteristics,etc.The properties of tellurene can be modulated by virtue of strain,defects,edges,and heterojunction effects.In view of so many unique properties,it has drawn significant interest since tellurene was predicted and fabricated successfully in 2017.In this paper,we review the 2D tellurene allotropes,experimental preparation,excellent properties,performance modulation and future development.

Structure and Photochemical Properties of a Chiral Cd Coordination Polymer Based on 4,4'-(Hexafluoroisopropylidene)Bis(benzoic acid)and 1,3-Di(pyridineyl)benzene

One new chiral metal-organic coordination polymer,[Cd2（dpb）（H2hfipbb）2]n,was obtained under hydrothermal conditions of 1,3-di（pyridineyl）benzene（dpb） and 4,4＇-（hexafluoroisopropylidene）bis（benzoic acid）（H2hfipbb）. The title compound reveals a three-dimensional（3D） framework with two types of helical chains [Cd（COO）]n,which are linked each other to further form a double helical chain [Cd2（COO）2]n by sharing the same Cd（Ⅱ） ions. The dpb connects the double helical chains to generate a 3D framework. These unique structures were studied by single-crystal X-ray and other spectroscopy techniques. In addition,the luminescent,fluorescence lifetime and second harmonic generation efficiency properties in the solid state have been studied.

Structure and Photophysical Properties of a Chiral 4-Fold Interpenetrated Zn(Ⅱ) Coordination Polymer Tuned by 4,4'-(Hexafluoroisopropylidene)bis(benzoic acid)and 1,3-Di(pyridineyl)benzene

A new three-dimensional（3D） chiral metal-organic coordination polymer, [Zn（dpb）（hfipbb）]n, was obtained under hydrothermal conditions by 1,3-di（pyridineyl）benzene（dpb） and 4,4-（Hexafluoroisopropylidene）bis（benzoic acid）（H2hfipbb）. The as-prepared sample was characterized by single-crystal X-ray diffraction, PXRD, elemental analysis, IR spectroscopy and TGA analysis. The title coordination polymer crystallizes in orthorhombic, space group P21212, with a=21.923（4）, b=23.594（4）, c=7.3042（13） , V=3778.1（12） 3, Dc=1.209 g/cm3, Mr=687.90, F（000）=1328, μ=0.713 mm（-1） and Z=4. The compound contains two types of helical chains [Zn（hfipbb）]n and [Zn（dpb）]n which are linked with each other to generate a 3D framework by sharing the same Zn（Ⅱ） cations. It displays a 4-fold interpenetrated 3D framework. In addition, the luminescence, fluorescence lifetime and the second harmonic generation（SHG） efficiency properties in the solid state have been studied.

A hybrid carboxylate-water decamer with a discrete octameric water moiety self-assembled in a 2D copper(Ⅱ) coordination polymer

An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon （lr,4r）-1,4-dimethylcyclohexane, is unambiguously trapped in a 2D Cu（II） mixed-ligand coordination polymer, {[Cu2（bpp）2（HzO）2（bpda）2]＇6H2O}n （1） （bpp = 1,3-bis（4-pyridyl）propane and H2bpda = 2,2＇-biphenyldicarboxylic acid）. The water octamer can be extended into a hybrid carboxylate-water decamer when carboxylic oxygen atoms from bpda2- are involved. Interestingly, the present hybrid decamer bears a similar structural topology to a butterfly （H2O）10 cluster. The reversible dehydration/hydration of 1 is determined by X-ray powder diffraction studies.

Construction of Two Chiral Bilayer Coordination Polymers Based on 2-（Pyridine-3-yl）-lH-4,5- imidazoledicarboxylate Ligand

Two novel isomorphic coordination polymers [Zn（HPyImDC）H20]（1） and [Co（HPylmDC）H20]（2） were synthesized from 2-（pyridine-3-yl）-lH-4,5-imidazoledicarboxylic acid（H3PylmDC） under hydrothermal conditions. Both the compounds crystallized in P21221 chiral space group, possessing left-hand helical chains and right-hand helical chains. Two types of helical chains connected with each other to form an interesting 2D bilayer structure which extended to a 3D supermolecular structure via the hydrogen-bonding interactions. Topology analysis shows that H3PylmDC ligand and metal center can be regarded as 3-connected T-shaped nodes, thus leading to a （3,3）- connected network with vertex symbol of （82.10）.

Novel 3-D Supramolecular Architectures Constructed from Zn^2＋ ions, Oxybis（4-benzoate） and Di（2-pyridyl）amine Ligands

Using the V-shaped oba dianions as bridging ligands and dpa molecules as terminal ligands, a new 1D helical coordination-polymeric chain, [Zn（oba）（dpa）]n [oba=oxybis（4-benzoate）, dpa=di（2-pyridyl）amine], was synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, UV-Vis and IR spectra, and TGA analysis. X-ray structural analysis revealed that, oba and dpa ligands played an important role in the self-assembly of the helical chains by providing potential supramolecular recognition sites for π-π aromatic stacking and hydrogen-bond interactions, resulting in the self-assembly of the （4,4） networks to give a 3-D supramolecular framework. The photoluminescence properties of the title compound were also investigated, showing intense blue photoluminescence properties at room temperature.

Assembly of Two Coordination Polymers Based on 2,2 ＇-Bipyridyl-4,4＇-dicarboxylic Acid Ligand

Two novel 2D coordination polymers, [Co（BPDC）DMSO]·DMSO（1）（BPDC=2,2＇-bipyridyl-4,4＇-dicar- boxylic acid） and [Zn（BPDC）DMF]·DMF（2）, were synthesized from 2,2＇-bipyridyl-4,4＇-dicarboxylic acid ligand （H2BPDC） under solvothermal conditions. Single crystal X-ray diffraction analyses reveal that compound 1 crystal- lizes in orthorhombic system and Pca21 space group with a=1.29628（13） nm, b=1.13721（13） nm, c=1.66457（19） nm, α=90°, β=90°, γ=90°, V=2.4538（5） nm3. Compound 2 crystallizes in monoclinic system and P21/c space group with a=0.9429（6） nm, b=1.4757（10） nm, c=1.5980（9） nm, α=90°, β=114°, γ=90°, V=2.030（2） nm3. Compounds 1 and 2 exhibit two different 3-connected hcb and fes topologies, respectively. The structures of the two compounds both contain interesting characters of double-helical chains（left- and right-handed helical chains）. Additionally, the mag- netic and luminescent properties of the two compounds were studied.

Homochiral Coordination Polymers from Single Helices to Multiple Helices Controlled by Metal Ions

Helix as essential molecular chiral phenomenon at supramolecular level offers an affective method to study chiral characteristic of homochiral coordination polymers(CPs).Herein,two homochiral CPs[Cd((R)-CBA)_(2)(3,5-DIT)]_(n)((R)-H_(2) CBA=(R)-4-(1-carboxyethoxy)benzoic acid,3,5-DIT=3,5-di(1 H-imidazol-1-yl)toluene,1-R)and[Zn((R)-CBA)(3,5-DIT)]_(n)(2-R)were synthesized under hydrothermal conditions.In complex 1-R,only a helical chain was built by chiral ligands(R)-CBA2-,ancillary ligands 3,5-DIT and Cd(Ⅱ)ions.After Cd(Ⅱ)ions were replaced by Zn(Ⅱ)ions under similar reaction system,Zn(Ⅱ),(R)-CBA^(2-)and/or 3,5-DIT formed six types of helices,resulting in complex 2-R.So,the metal ions played a key role in the construction of helical structures.Complexes 1-R and 2-R were also characterized by elemental analysis,PXRD,TGA,CD and UV-visible absorptions.In addition,complexes 1-R and 2-R exhibited different photoluminescence behaviors in solid sate compared to free ligand(R)-H_(2)CBA.

Characterization of acid-and pepsin-soluble collagens from spines and skulls of skipjack tuna(Katsuwonus pelamis)

Acid-soluble collagen(ASC) and pepsin-soluble collagen(PSC) from the spine(ASC-SP and PSC-SP) and skull(ASC-SK and PSC-SK) of the skipjack tuna, Katsuwonus pelamis, were successfully isolated and characterized. The yields of ASC-SP, PSC-SP, ASC-SK and PSC-SK were(2.47 ± 0.39)%,(5.62 ± 0.82)%,(3.57 ± 0.40)%, and(6.71 ± 0.81)%, respectively, on the basis of dry weight. The four collagens contained Gly(330.2-339.1 residues/1 000 residues) as the major amino acid, and their imino acid contents were between 168.8 and 178.2 residues/1 000 residues. Amino acid composition, SDS-PAGE, and FTIR investigations confirmed that ASC-SP and ASC-SK were mainly composed of type I collagen, and had higher contents of high-molecular weight cross-links than those of PSC-SK and PSC-SP. The FTIR investigation also certified all the collagens had triple helical structure. The denaturation temperatures of ASC-SK, PSC-SK, ASC-SP, and PSC-SP were 17.8, 16.6, 17.6, and 16.5 °C, respectively. All isolated collagens were soluble at acidic pH(1-5) and lost their solubilities when the NaCl concentration was above 2%(W/V). The isolated collagens from the spines and skulls of skipjack tuna could serve as an alternative source of collagens for further application in food, cosmetic, biomedical, and pharmaceutical industries.