Two Novel Homochiral Enantiomorphic 3D Metal-organic Frameworks:Synthesis,Crystal Structure,Luminescent and SHG Properties

Two homochiral enantiomorphic 3D coordination polymers： （D-HAPA）2[Cd2Cs（D- HAPA）（m-BDC）4]＇（EtOH） （1D） and （L-HAPA）2[Cd2Cs（L-HAPA）（m-BDC）a]＇（EtOH） （1L） （APA = 2-amino-l-propanol, m-H2BDC = 1,3-benzenedicarboxylate）, have been assembled solvothermally respectively with the induction of enantiomorphic organic small molecules （D,L-APA）. 1L and 1I） crystallize in chiral space group P21 with Flack parameters of-0.012（13） and -0.07（3）, respectively, and have been characterized by satisfactory elemental analysis, FT-IR spectra, CD-spectra and single-crystal X-ray diffraction. They both exhibit sqp topological net, purple fluorescence and SHG activity.

MIL-53-based homochiral metal-organic framework as a stationary phase for open-tubular capillary electrochromatography

Homochiral metal-organic frameworks(MOFs)have attracted considerable attention in many fields of research,such as chiral catalysis and chiral chromatography.However,only few homochiral MOFs can be effectively used in capillary electrochromatography(CEC)and their performances are far from adequate.In this study,we successfully synthesized achiral nanocrystalline MIL-53.A facile post-synthetic modification strategy was then implemented to functionalize the product,yielding a homochiral MOF:L-His-NH-MIL-53.This MOF was then employed as a chiral coating in open-tubular CEC mode(OT-CEC),and,as such,it exhibited high enantioselectivities for several racemic drugs.The homochiral MOF and the fabricated capillary coating were systematically characterized using transmission electron microscopy,scanning electron microscopy(with energy-dispersive X-ray spectrometry),Fourier-transform infrared spectroscopy,X-ray diffractometry,thermogravimetric analysis,circular dichroism spectroscopy,Brunauer-Emmett-Teller surface area measurements,and X-ray photoelectron spectroscopy.This study is expected to provide a new strategy for the design and establishment of MOF-based chiral OT-CEC systems.

A Pair of 3D Homochiral Coordination Polymers with Open Channels Constructed by Lactic Acid Derivative Ligands and In-situ Formed Anions

With the help of in-situ formed CH_3COO- anion, a pair of 3D homochiral coordination polymers with open channels were constructed by the assembly of lactic acid derivative ligands, 1.4-DIB ligands and Cd（II） ions, namely [Cd3（（R）-CIA）2（CH3CO2）_2（1.4-DIB）2（H2O）2]·x（Guest）（1-D） and [Cd3（（S）-CIA）2（CH3CO2）2（1.4-DIB）2（H2O）2]·x（Guest）（1-L）. They contain 1D interesting ladder-like Cd-（R）-CIA（3-） chains and exhibit SHG-active behavior and photoluminescent property.

Syntheses and Characterization of Homochiral Three- dimensional Lanthanide-organic Frameworks Based on Ln_4O_4 Clusters and L-Aspartic Acid

Four isostructural lanthanide compounds formulated as {[Ln4（μ3-OH）4（L-asp）3- （H2O）10]（ClO4）5·10H2O}n （Ln=Nd （1）, Sm （2）, Eu （3）, Gd （4）; asp=aspartic acid） were synthe- sized by a conventional solution reaction. Their structures were characterized by single-crystal X-ray diffraction, IR spectroscopy and elemental analyses （EA）. It reveals that they crystallize in the chiral P212121 space group. Their structures feature a homochiral three-dimensional （3D） lan- thanide-organic framework, which contains a cubic [Ln4（μ3-OH）4]8＋ cluster sub-building unit （SBU）. Additionally, the photoluminescence property of Eu compound was investigated in the solid-state at room temperature.

The role of nickel(II) on the homochirality of amino acids in living systems

The origin of homochirality in living organisms is controversial,stands out of being particularly important and a question which is still not satisfactorily answered.A mental picture of sequence of events that is thought to have preceded the existence of chirality in molecules is described.A chemical model to mimic the original abiotic conditions in an attempt to explain the preference of homochirality in living systems was tried.The effect which might have influenced this preference is presented.The surpri...

Homochirality in Ferroelectrochemistry

What is the most favorite and original chemistry developed in your research group?We originally proposed the design principle for molecular ferroelectrics:ferroelectrochemistry,including quasi-spherical theory,the introduction of homochirality,and H/F substitution.Ferroelectrochemistry changed the blind search for molecular ferroelectrics into targeted chemical design,which will develop into a new discipline.

Hierarchical Homochiral Assembly of Polyhedral Cage-Type Nanoclusters

Hierarchical chiral self-assembly is of profound significance for biomolecules for their biological functions.Atom-precise metal nanoclusters(NCs)offer better opportunities to construct hierarchical superlattices.Nevertheless,achieving hierarchical homochiral assembly of nanocrystals protected by achiral ligands has proven to be a formidable task,with existing examples primarily limited to heterochiral assembly.Here we put forward a hierarchical assembly strategy towards precisely fabricating highly ordered homochiral superstructures.First,clusterin-nanocage type copper-hydride NCs act as synthons,of which entity is featured with a hexagonal close-packed Cu_(9)kernel embedded in a C_(3)-symmetric trigonal-prismatic metallacage,leading to a chiral core-shell primary structure with either P or M conformation.Then four homochiral NCs combined with guests through synergistic noncovalent interactions spontaneously organize into a supramolecular tetrahedral secondary structure within a unit cell.Finally,these nanoscopic supramolecular motifs pack into tertiary hierarchical superlattice of chiral cubic crystalline phase.Additionally,the crystalline material shows excellent robustness,and fascinating blueexcitable near-infrared thermally activated delayed fluorescence behavior.This work not only exhibits that nanocage-type NCs can be smart as proteins to translate chiral primary structure into tertiary chiral hierarchical complexity,but also provides new insights into structure-to-superstructure,enabling bottom-up creation of higher-level hierarchical homochiral superlattice structures.

Synthesis, Crystal Structure and Luminescence of One-dimensional Homochiral Terbium (Ⅲ) Coordination Polymers

Enantiomerically pure lanthanide(Ⅲ)-based phosphonates are successfully synthesized by using(R)-or(S)-(1-phenylethylamino)-methylphosphonate acid(pempH2),namely,R-or S-[Tb3(pempH2)2(pempH)7]-Cl2·H2O(R-Tb or S-Tb),crystallizing in chiral space group P212121.Compound R-Tb shows a one-dimensional homochiral triple-stranded helical chain structure where the Tb(III)atoms are bridged by O-P-O units andμ3-O(P)bridge.The thermal analysis,photoluminescence as well as optically active properties of compounds R-Tb and S-Tb have also been investigated.

A new theoretical model for the origin of amino acid homochirality

Amino acid homochirality, as a unique behavior of life, could have originated synchronously with the genetic code. In this paper, phosphoryl amino-acid -5′-nucleosides with P-N bond are postulated to be a chiral origin model in prebiotic molecular evolution. The enthalpy change in the intramolecular interaction between the nucleotide base and the amino-acid side-chain determines the sta-bility of the particular complex, resulting in a preferred conformation associated with the chirality of amino acids. Based on the theoretical model, our experiments and calculations show that the chiral selection of the earliest amino acids for L-enantiomers seems to be a strict stereochemi-cal/physicochemical determinism. As other amino acids developed biosynthetically from the earliest amino acids, we infer that the chirality of the later amino acids was inherited from the precursor amino acids. This idea probably goes far back in history, but it is hoped that it will be a guide for further ex-periments in this area.

Homochiral expression of proteins:a discussion on the natural chirality related to the origin of life

Homochirality in life has always been a driving force in scientific research and natural exploration. It has not been satisfactorily explained, and systematic investigations are necessary. This paper reported a homochiral expression of proteins dependent on the stirring direction of growing media. By controlling the stirring direction clockwise (CW) and anticlockwise (ACW) of the culture medium, proteins with distinct secondary structures were obtained, and D-amino acid may be included in the protein cultured with the stirring direction of ACW. Considering the effect of force fields, which might affect the process of folding and refolding of cellular protein in this report, the control of force fields might be a good way to prepare asymmetric drugs, and the rotational direction of the earth is possibly related to the chirality in primitive life molecules.

Ferroelectricity based on coordination compound:Transition metal Co(Ⅱ) sulfates templated by homochiral2-methylpiperazine(C_5H_(14)N_2)[Co(H_2O)_6](SO_4)_2

Reacting homochiral （R）-2-methylpiperazine with cobalt sulfate heptahydrate by the solution method in the presence of concentrated sulfuric acid （H2SO4） yielded two coordination compounds （C5H14N2） [CO（H2O）6]（SO4）2 （1 and 2）. They are polymorphs, but their hydrogen bonds structure differ significantly. Both 1 and 2 crystallize in chiral space group P21 which is related with point group C2, and experimental results suggest that 1 displays ferroelectric behaviors.

A Gas Chromatographic Stationary of Homochiral Metal-peptide Framework Material and Its Applications

Homochiral metal-organic frameworks（HMOFs） have special properties, such as high surface area, fasci- nating structures and excellent chemical and thermal stability and they have broad application prospects. In this work, we reported the use of HMOF Co-L-GG（L-GG, dipeptide H-Gly-L-Glu） as the stationary phase for separating race- mates m gas chromatography. Co-L-GG coated fused silica capillary colunm（10 m×250 μm i.d.） was prepared via a dynamic coating method. Thirty racemmes belonging to different classes of organic compounds were resolved in- cluding halohydrocarbons, ketones, esters, ethers, organic acids, epoxyalkanes, alcohols and sulfoxides. When com- pared with the previously reported chiral MOFs-coated capillary colurnlls, the Co-L-GG coated column exhibited broader chiral resolution ability towards chiral compounds.

Enantioselective epoxidation of nonfunctionalized alkenes catalyzed by recyclable new homochiral bis-diamine-bridged bi-Mn(salen) complexes

Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen＇s catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also 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.

Synthesis of homochiral spiro[4.4] nonane-1,6-diols

Homochiral cis, cis-; cis,trans- and trans, trans-spiro[4.4]nonane-1,6-diols were prepared via diastereoselective reduction of enantiomerically pure spiro[4.4]nonane-1,6-dione (1) with the corresponding reducing agents: lithium n-butyldiisobutylaluminium hydride for cis,cis-diol (2) with 88% yield; BH3. HF for cis,trans-diol (3) with 91% yield; LiAlH4 for trans,trans-diol (4) with 15% yield.

An 8-Connected Chiral Lanthanide Metal-organic Framework Constructed from Naturally Camphoric Acid:Crystal Structure,Vibrational Circular Dichroism Spectroscopy and Second-order Nonlinear Optical Effect

A chiral lanthanide metal-organic framework based on enantiopure camphoric acid （D-H2cam）, [Nd3（D-cam）8（H2O）4Cl]n （1）, has been synthesized and characterized by single-crystal X-ray structural analysis, elemental analysis, IR, thermal gravimetric, and X-ray powder diffraction. Crystal data for the title compound are as follows： orthorhombic system, space group P212121 with a = 13.8287（7）, b = 14.0715（7）, c = 25.7403（12） A^°, V = 5008.8（4） A^°3, Mr = 1333.08, Z = 4, F（000） = 2644, Dc = 1.768 g/cm^3, μ（MoKα） = 3.189 mm^-1, the final R = 0.0351 and wR = 0.0814 （I 〉 2σ（I））. Compound 1 displays an 8-connected bcu topology 3D framework and hydrogen-bonding interactions stabilize the solid-state structure. The vibrational circular dichroism （VCD） spectrum and second-order nonlinear optical effect of compound 1 have been studied in the solid state.

A Zeolitic rho-type Chiral Metal-organic Framework Based on L-alanine

One new chiral zeolitic rho-type metal-organic framework [Cd（L-ala）2]n（1） has been successfully synthesized based on L-alanine chiral ligand, which demonstrates the feasibility of fabricating MOF that integrates the 4-connected zeotype topology by the employment of L-alanine. To the best of knowledge, it’s the first report that metal-organic framework based on amino acid features the chiral zeolitic rho-type structure. Compound 1 was characterized by X-ray powder diffraction, elemental analysis and single-crystal X-ray diffraction. Crystal data: C6 H9 CdN2 O4, Mr = 285.55, cubic system, space group I432, a = 24.0795（6）, V = 13961.9（10） ?3, Z = 48, Dc = 1.630 Mg/m3, F（000） = 6672, μ（Mo Kα） = 1.865 mm-1, S = 1.058, R = 0.0271 and wR = 0.0312 for 1870 observed reflections with I > 2σ（I）. The circular dichroism（CD） property of compound 1 was also investigated.

A novel and concise synthetic access to chiral 2-substituted-4-piperidone

A novel and concise synthetic access to enantiopure chiral 2-aryl/alkyl substituted 4-piperidone has been demonstrated.This new route features two key steps:the highly diastereoselective conjugate addition of homochiral lithium amides to trans-β-substituted-α,β-unsaturated methyl esters guaranteed the enantiopurity at 2 position(de>19:1)and the intramolecular attacking of carbanions to methyl esters led to the formation of the piperidone ring.A wide range of substrates,including chiral2-aryl and 2-alkyl-4-piperidones,were successfully synthesized with modest to high yield.Moreover,some non-chiral3-substituted-4-piperidones were also synthesized with enhanced ring-formation yield,implicating the versatility of this method in construction of various piperidine rings.