This critical review presents the various synthetic approaches and chiral chemistry of metal–camphorate frameworks (MCamFs), which are homochiral metal–organic frameworks (MOFs) constructed from a camphorate ligand. The interest in this unique subset of homochiral MOFs is derived from the many interesting chiral features for both materials and life sciences, such as asymmetrical synthesis or crystallization, homochiral structural design, chiral induction, absolute helical control and ligand handedness. Additionally, we discuss the potential applications of homochiral MCamFs. This review will be of interest to researchers attempting to design other homochiral MOFs and those engaged in the extension of MOFs for applications such as chiral recognition, enantiomer separation, asymmetric catalysis, nonlinear sensors and devices.

Chiral chemistry of metal-camphorate frameworks.

Research on hybrid inorganic-organic materials has experienced an explosive growth since the 1980s, with the expansion of soft inorganic chemistry based processes. Indeed, mild synthetic conditions, low processing temperatures provided by “chimie douce” and the versatility of the colloidal state allow for the mixing of the organic and inorganic components at the nanometer scale in virtually any ratio to produce the so called hybrid materials. Today a high degree of control over both composition and nanostructure of these hybrids can be achieved allowing tunable structure-property relationships. This, in turn, makes it possible to tailor and fine-tune many properties (mechanical, optical, electronic, thermal, chemical…) in very broad ranges, and to design specific multifunctional systems for applications. In particular, the field of “Hybrid-Optics” has been very productive not only scientifically but also in terms of applications. Indeed, numerous optical devices based on hybrids are already in, or very close, to the market. This review describes most of the recent advances performed in this field. Emphasis will be given to luminescent, photochromic, NLO and plasmonic properties. As an outlook we show that the controlled coupling between plasmonics and luminescence is opening a land of opportunities in the field of “Hybrid-Optics”.

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Optical Properties of Hybrid Organic-Inorganic Materials and their Applications

Alkaline-earth metal ions were used to tune four new heterometallic frameworks, {[Cd2.07Mg0.93(BTC)2(H2O)4]·2H2O}n (1), {[Cd2Ca(BTC)2(H2O)4]·2H2O}n (2), {[Cd2Sr(BTC)2(H2O)5]·H2O}n (3) and [Cd6Ba3(BTC)3(H2O)10]n (4) (H3BTC = 1,3,5-benzenetricarboxylic acid), synthesized from H3BTC and the corresponding metal salts. Single-crystal X-ray analysis shows that compound 1 is a three-dimensional (3D) framework based on heterometallic Cd–O–Cd–O–Mg inorganic chain subunits, compounds 2 and 3 are basically isostructural and feature a 3D framework based on Ca(II) or Sr(II) polyhedrons decorated with Cd–O–Cd inorganic chains. Compound 4 is a 3D framework templated by disordered inorganic hydrate Ba(II) ions, and also features inorganic Cd–O–Cd chains, which are connected together through corner sharing with the {Cd1O6} polyhedrons by {Ba1O6} polyhedrons, giving rise to a rare heterometallic 3D inorganic skeleton. Moreover, the solid-state fluorescence of compounds 1–4 and NLO properties of compounds 2–4 have also been investigated at room temperature.

Using alkaline-earth metal ions to tune structural variations of 1,3,5-benzenetricarboxylate coordination polymers

Two new three-dimensional (3D) multinodal Cd(II)–organic frameworks, [Cd3(dccpa)(bipy)0.5(H2O)4]·5H2O (1) and [(CH3)2NH2]2[Cd11(dccpa)4(DMF)4(H2O)8]·4H2O (2) (H6dccpa = 3,4-di(3,5-dicarboxyl phenyl) phthalic acid, bipy = 4,4′-bipyridine), have been prepared and fully characterized. Compound 1 possesses a 3D neutral framework with a new (6,6,7)-connected topology based on a single trinuclear cluster, while 2 features a 3D anionic framework with a new (5,6,6,10)-connected topology containing mixed trinuclear and pentanuclear clusters. Remarkably, 1 and 2 show promising photocatalytic activities toward the degradation of rhodamine B and methyl blue, which suggests that different kinds of cluster units may exert different impacts on the decomposition of organic dyes.

Assembly of Two Novel Cd3/(Cd3 + Cd5)-Cluster-Based Metal–Organic Frameworks: Structures, Luminescence, and Photocatalytic Degradation of Organic Dyes

The assembly of a fluorescent dicarboxylate ligand with a barium ion resulted in the formation of a 3D metal–organic framework, Ba5(ADDA)5(EtOH)2(H2O)3·5DMF (UPC-17), based on a 1D rod-shaped secondary building unit. The unprecedented solvent-dependent sensitivities of UPC-17 for the detection of Fe3+/Al3+ ions and 4-nitrophenol with high efficiency were observed for the first time. Significantly, UPC-17 exhibits superior “turn-off” detection for the Fe3+ ion in methanol and acetone emulsions but shows “turn-on” detection in tetrahydrofuran emulsion. Furthermore, the visible color changes in the detection process make them easy to distinguish by the naked eye, which further increases its application potential.

Unprecedented Solvent-Dependent Sensitivities in Highly Efficient Detection of Metal Ions and Nitroaromatic Compounds by a Fluorescent Barium Metal-Organic Framework.

Alkaline earth metal ion doped Zn(II)-terephthalates, [Zn2Mg(PBDC)3(DMA)2]n (1), [ZnCa(PBDC)2(DMA)2]n (2), [ZnSr(PBDC)2(DMA)2]n (3) and [Zn2Ba(PBDC)3(μ2-O1w)2(DMF)]n·n(DMF) (4) (H2PBDC = terephthalic acid, DMA = N,N′-dimethylacetamide, DMF = N,N′-dimethylformamide), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, IR spectra, and thermal analyses. Different secondary building subunits, [Zn2Mg(μ2-COO)3] for 1, [ZnCa(μ2-COO)3] for 2, [ZnSr(μ2-COO)3] for 3, and [Zn2Ba(μ2-COO)4(μ2-O1w)2] for 4, are realized by the introduction of different alkaline earth ions. Compound 1 is a two-dimensional (2D) layer structure with 6-connected hxl topology. Compounds 2 and 3 are isostructural and exhibit a three-dimensional (3D) framework with (3,5)-connected {4.62}{4.66.83} topology owing to their similar secondary building subunits. Compound 4 is a three-dimensional (3D) opened framework with the channels occupied by the disordered lattice DMF molecules and can be simplified into a (3,8)-connected {42.6}2{44.614.78.82} topology. Moreover, the solid-state fluorescence of compounds 1–4 have also been investigated at room temperature.

Alkaline earth metal ion doped Zn(II)-terephthalates

Solvothermal reactions of Ca(NO3)2 or Ba(NO3)2 with aromatic carboxylate ligands afforded four new inorganic–organic hybrid frameworks, [Ca(PBDC)(H2O)3]n (1), [Ca(OBDC)(H2O)]n (2), [Ba5(OBDC)4(H2O)2(NO3)2]n (3), and [Ba3(BTC)2(H2O)4]n (4) (H2PBDC = terephthalic acid, H2OBDC = phthalic acid, H3BTC = 1,3,5-benzenetricarboxylic acid). These compounds have been fully characterized by single crystal X-ray diffraction, powder X-ray diffraction, satisfactory elemental analysis, IR spectra, and TG analysis. X-ray analysis shows that compound 1 features a one-dimensional chain (1D) structure with the I1O0 connectivity, both compound 2 and compound 3 feature a two-dimensional (2D) layer structure with the I1O1 connectivity, I2O0 connectivity, respectively, compound 4 features a three-dimensional (3D) framework with a rare I3O0 connectivity. Thermal stabilities and luminescent properties of compounds 1–4 and NLO property of compound 4 have also been investigated.

A Series of Ca(II) or Ba(II) Inorganic–Organic Hybrid Frameworks Based on Aromatic Polycarboxylate Ligands with the Inorganic M–O–M (M = Ca, Ba) Connectivity from 1D to 3D

Two distinct Dy-isophthalates induced by different solvents

Construction of Cu-Ce composite oxides by simultaneous ammonia evaporation method to enhance catalytic performance of Ce-Cu/SiO2 catalysts for dimethyl oxalate hydrogenation

Huang Yuanyuan

Papers

Using alkaline-earth metal ions to tune structural variations of 1,3,5-benzenetricarboxylate coordination polymers

Alkaline earth metal ion doped Zn(II)-terephthalates

A Series of Ca(II) or Ba(II) Inorganic–Organic Hybrid Frameworks Based on Aromatic Polycarboxylate Ligands with the Inorganic M–O–M (M = Ca, Ba) Connectivity from 1D to 3D

Two distinct Dy-isophthalates induced by different solvents

Construction of Cu-Ce composite oxides by simultaneous ammonia evaporation method to enhance catalytic performance of Ce-Cu/SiO2 catalysts for dimethyl oxalate hydrogenation