M. S. Zavakhina

Porous metal–organic frameworks (MOFs) as matrices for inclusion compounds

Inclusion compounds based on metal–organic frameworks (MOFs) have promising practical application in gas storage, separation and fine purification of substances, as well as in catalysis. MOFs are crystalline compounds consisting of metal ions coordinated by bridging organic ligands that form porous structures. The kinetics of the thermal decomposition of the frameworks themselves, namely [Co2(camph)2bpy] and [Co2(asp)2bpy], was investigated (camph and asp are the anions of camphoric and aspartic acids, bpy is the organic amine, 4,4′-bipyridyl). The empty coordination polymer framework based on metal camphorates was thermally (kinetically) less stable than the polymer framework based on metal aspartate. A high kinetic stability of frameworks with aspartic complexes during heating was due to the entropic factor rather than the enthalpic one.

Synthesis, Crystal Structure, and Luminescence Properties of Coordination Polymers Based on Cadmium Isonicotinates

Heating a solution of cadmium nitrate and isonicotinic acid in N,N′-dimethylformamide or dimethyl sulfoxide gave three new coordination polymers, [Cd(Inic)2] · 0.5DMF (I), [Cd3(DMSO)6(Inic)2(SO4)2] (II), and [{Cd(DMSO)(Inic)}2(SO4)] · 2H2O (III), which were studied by X-ray crystallography. Compounds I and III were characterized by IR spectroscopy and elemental and thermogravimetric analyses and luminescence spectroscopy.

Supramolecular interactions in double-chain coordination polymers based on copper(I) cations with chiral linkers

Two double-chain chiral coordination polymers [CuI2(bpy)2(phlac)](NO3)·H2O (1) and [CuI2(bpy)2(clman)](NO3)·H2O (2) were obtained by heating a DMF/H2O solution of copper(II) nitrate, 4,4′-bipyridyl (bpy), S-3-phenyllactic (Hphlac) or R-3-chloromandelic (Hclman) acid. The compounds were structurally characterized by X-ray crystallography.

Three-dimensional copper(II) carboxylates based on 4,4′,4″-benzene-1,3,5-triyltris(benzoic acid)

The homochiral coordination polymers [Cu4(CH3OH)(H2O)4(Hbtb)(S-mal)2]•4H2O and [Cu4(CH3OH)(H2O)4(Hbtb)(R-mal)2]•4H2O were synthesized by heating S- or R-malic acid (H3mal), 4,4′,4″-benzene-1,3,5-triyltris(benzoic acid) (H3btb), and copper(II) acetate in an aqueous methanolic solution. The reaction with copper(II) nitrate in aqueous dioxane afforded the coordination framework [Cu6(C4H8O2)3(H2O)3(btb)4]•4C4H8O2•10H2O, which does not contain chiral ligands. The compositions and crystal structures of the new compounds were determined by single-crystal X-ray diffraction and confirmed by X-ray powder diffraction, IR spectroscopy, thermogravimetric and elemental analysis.

Synthesis and characterization of chiral copper( ii ) coordination polymers with 4,4´-bipyridine and lactic acid derivatives

Chiral 2D and 3D metal-organic coordination polymers [Cu2(bpy)2(Hdml)2(HCOO)]-(HCOO)·2H2O (1) and [Cu(bpy)(Hphl)(HCOO)]·H2O (2) were synthesized by heating a solution of copper(ii) salts, 4,4´-bipyridine (bpy), and α-hydroxycarboxylic acids, viz., S-3,3-dimethyllactic (H2dml) or S-3-phenyllactic (H2phl) acid, in a water—N,N´-dimethylformamide mixture. The structures of compounds 1 and 2 were determined by single-crystal X-ray diffraction. Compound 2 was characterized by X-ray powder diffraction, IR spectroscopy, thermogravimetric analysis, and elemental analysis.

Crystal structure of the coordination polymer [Cu2(S-mal)2(bpy)2(H2O)]·2.5H2O

In the interaction of basic copper carbonate with optically pure malic acid and 4,4′-bipyridine [Cu2(S-mal)2(bpy)2(H2O)]·2.5H2O (1) is obtained. The structure of the metal-organic coordination polymer is unique for this class of compounds, which is established by the single crystal X-ray diffraction analysis using synchrotron radiation.

Synthesis and structure of chiral coordination polymers of CoII, CuII, and MgII saccharates

Chiral metal-organic coordination polymers [Co2(sacch)2]·1/2H2O·CH3OH (1), [Cu(sacch)(H2O)2]·3H2O (2), and [Mg(H2O)3(sacch)] (3) (H2sacch is d-saccharic acid) were synthesized from aqueous or water-methanol solutions of potassium hydrogen saccharate and a salt of the corresponding metal. The compositions and structures of the resulting compounds were determined by single-crystal X-ray diffraction and confirmed by X-ray powder diffraction, IR spectroscopy, thermogravimetry, and elemental analysis.

Structure of a framework coordination polymer Zn2(dmf)(H2O)(atc)]·0.75DMF·0.5H2O

In the interaction of Zn(NO3)2·6H2O and adamantane-1,3,5,7-tetracarboxylic acid (H4atc) in N,N′-dimethyl formamide (DMF) a three-dimensional coordination polymer with the composition [Zn2(dmf)(H2O)(atc)]·0.75DMF·0.5H2O (1) is produced. Its structure is determined by a single crystal X-ray diffraction study.

Crystal structure of metal-organic coordination polymers [Cu(bpy)2(H2O)2](NO3)2·4.5C2H5OH and [Cu2(bpy)(H2O)(L-pha)2](NO3)2·H2O

Two metal-organic coordination polymers [Cu(bpy)2(H2O)2](NO3)2·4.5C2H5OH (1) and [Cu2(bpy)(H2O)(L-pha) 2](NO3)2·H2O (2) (L-Hpha = L-phenylalanine, bpy = 4,4′-bipyridyl) are prepared by slow evaporation of an aqueous alcoholic solution of copper nitrate, L-phenylalanine, and 4,4′-bipyridyl. The structure and composition of the obtained compounds are determined by single crystal XRD. The framework of compound 1 is positively charged and forms two types of intersecting channels. Compound 2 is a homochiral metal-organic coordination polymer whose structure contains L-phenylalanine anions.

Chiral guest in a chiral framework: X-ray diffraction study

The inclusion compound of zinc lactate terephthalate with R-butan-2-ol, [Zn2(R-BusOH) (bdc)(S-lac)]•(R-BusOH) (BusOH is butan-2-ol, H2bdc is terephthalic acid, S-H2lac is lactic acid), was prepared by soaking crystals of [Zn2(dmf)(bdc)(S-lac)]•DMF in pure R-butan-2-ol. The positions of chiral alcohol molecules in voids of the chiral framework and the host–guest contacts were determined by X-ray diffraction. These data provide an explanation for the origin of chiral discrimination of zinc lactate terephthalate toward the R-isomer of butan-2-ol.