Elham Motyeian

Bio: Elham Motyeian is an academic researcher from Payame Noor University. The author has contributed to research in topics: Pyridine & Crystal structure. The author has an hindex of 6, co-authored 14 publications receiving 90 citations.

catena‐Poly[piperazindiium [zincate(II)‐bis(μ‐pyridine‐2,3‐dicarboxylato)‐κ3N,O2:O3;κ3O3:N,O2] tetrahydrate]

Abstract: The centrosymmetric title compound, {(C4H12N2)[Zn(C14H6N2O8)2]·4H2O}n or {(pipzH2)[Zn(py-2,3-dc)2]·4H2O}n, where py-2,3-dcH2 is pyridine-2,3-dicarboxylic acid and pipz is piperazine, was obtained by the reaction of zinc(II) nitrate tetra­hydrate with (pipzH2)(py-2,3-dc) as a proton-transfer compound in aqueous solution. Each ZnII (site symmetry {\overline 1}) is coordinated in a distorted octa­hedral geometry by four O atoms and two N atoms from two bidentate (py-2,3-dc)2− ligands, which also act as bridging ligands between ZnII atoms. The four donor atoms of the two coplanar (py-2,3-dc)2− anions form a square-planar arrangement around the ZnII centre. In the crystal structure, extensive O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, as well as ion pairing and π–π stacking [with a distance of 3.8693 (8) A between two aromatic rings] between different fragments, play an important role in the stabilization of the supra­molecular structure.

Synthesis and Crystal Structure of Mn(II) and Hg(II) Compounds and Solution Studies of Mn(II), Zn(II), Cd(II) and Hg(II) Compounds Based on Piperazinediium Pyridine-2,3-dicarboxylate

Abstract: Novel metal organic frameworks including {(pipzH2)[Mn(py-2,3-dc)2]·7.75H2O}n, 1, {(pipzH2)[Zn(py-2,3-dc)2]·4H2O}n, 2, [Cd(py-2,3-dc)(H2O)3]n, 3 and {(pipzH2)[Hg4Cl10]}n, 4, in which pipz is piperazine and py-2,3-dcH2 is pyridine-2,3-dicarboxylic acid were synthesized applying a proton transfer ion pair i.e. (pipzH2)(py-2,3-dcH)2 and corresponding metallic salts and studied by IR, 1H NMR, 13C NMR spectroscopy and single crystal X-ray diffractometry. The space group of compounds 1 and 4 are P21/c and C2/c of monoclinic system, respectively. The crystal dimensions are a = 20.108(2) A, b = 19.910(2) A, c = 12.997(1) A, β = 94.354(2)° for 1 and a = 15.940(1) A, b = 11.2690(9) A, c = 11.1307(9) A, β = 90.685(2)° for 4. The crystal structures of 2 and 3 have been reported previously. However, their solution studies are discussed here. The compounds had all polymeric structures. Although ZnII, CdII and HgII were elements of the same group, their behavior against the ion pair was essentially different. Various supramolecular interactions mainly hydrogen bonds of the type O-H⋯O, N-H⋯O, C-H⋯O, N-H…Cl and C-H⋯Cl were observed in the structures. There was an unusual and huge water cluster in the structure of compound 1. The solution states of compounds 1–4 were studied and reported. The protonation constants of pipz and py-2,3-dc, the py-2,3-dc/pipz proton transfer equilibrium constants and stoichiometry and stability of the system with Mn2+, Zn2+, Cd2+ and Hg2+ ions in aqueous solution were investigated by potentiometric pH titrations.

Bis(guanidinium) bis-(4-hydroxy-pyridine-2,6-dicarboxyl-ato-κO,N,O)nickel-ate(II) dihydrate.

Abstract: The reaction of nickel(II) nitrate hexa­hydrate, guanidine (G) and 4-hydroxy­pyridine-2,6-dicarboxylic acid (hypydcH2) in a 1:2:2 molar ratio in aqueous solution resulted in the formation of the title compound, (CH6N3)2[Ni(C7H3NO5)2]·2H2O or (GH)2[Ni(hypydc)2]·2H2O. The six donor atoms of the two 4-hydroxy­pyridine-2,6-dicarboxyl­ate or (hypydc)2− ligands form a distorted octa­hedral arrangement around the NiII centre. Considerable C—O⋯π stacking inter­actions between the CO groups of carboxyl­ate fragments and the pyridine rings of (hypydc)2− with a distance of 3.3212 (8) A are observed. In the crystal structure, a wide range of noncovalent inter­actions consisting of hydrogen bonding (of the types O—H⋯O and N—H⋯O), ion pairing, and π–π [centroid–centroid distance 3.8037 (5) A], N—H⋯π and C—O⋯π stacking inter­actions connect the various components into a supra­molecular structure.

Diaquabis(pyridine‐2‐carboxylato)magnesium(II) 0.15‐hydrate

Abstract: The reaction of magnesium(II) chloride tetra­hydrate with the proton-transfer compound piperazinediium pyridine-2-carboxyl­ate, (pipzH2)(pyc)2 (pipz is pirerazine and pycH is pyridine-2-carboxylic acid) in aqueous solution leads to the formation of the title compound, [Mg(C6H4NO2)2(H2O)2]·0.15H2O. The Mg atom is six-coordinated in a distorted octa­hedral environment by two bidentate pyridine-2-carboxyl­ate groups and two O atoms of coordinated water mol­ecules, which are located in cis positions. In the crystal structure, inter­molecular O—H⋯O and C—H⋯O hydrogen bonds, and π–π [π–π distance = 3.5616 (8) A for pyridine rings; symmetry code: 2-x, 1-y, 1-z] and C—H⋯π stacking, connect the various components into a supra­molecular structure.

Aqua-(4-hydroxy-pyridine-2,6-dicarboxyl-ato)(1,10-phenanothroline)copper(II) 4.5-hydrate.

Abstract: The title compound, [Cu(C7H3NO5)(C12H8N2)(H2O)]·4.5H2O or [Cu(hypydc)(phen)(H2O)]·4.5H2O (phen is 1,10-phenanthroline and hypydcH2 is 4-hydroxy­pyridine-2,6-dicarboxylic acid), was obtained by the reaction of copper(II) nitrate hexa­hydrate with the proton-transfer compound (phenH)2(hypydc) in aqueous solution. Both the cationic and the anionic fragments of the proton-transfer compound are involved in complexation. Each CuII atom has a distorted octa­hedral geometry. It is hexa­coordinated by three O atoms and three N atoms, from one phen fragment (as bidentate ligand), one (hypydc)2− unit (as tridentate ligand) and a water mol­ecule. In the crystal structure, O—H⋯O and C—H⋯O hydrogen bonds, and π–π stacking inter­actions [centroid-to-centroid distance 3.5642 (11) A] between the phen ring systems, contribute to the formation of a three-dimensional supra­molecular structure.

A brief review of structural concepts of novel supramolecular proton transfer compounds and their metal complexes (part II)

Abstract: In continuation of our previous brief review of structural concepts of novel supramolecular proton transfer compounds and their metal complexes by Aghabozorg et al. [1], we briefly surveyed the current research in the field of proton transfer compounds supramolecular synthons and their self-assembled metallic complexes from the points of view of Crystal Engineering and Density Functional Theory (DFT) since 2008. Our research groups have recently focused on the proton delivery from acids, which are considered to be suitable proton donors, to amines as proton acceptors. The results were the production of several proton transfer ion pairs possessing some remaining donor sites applied for coordination to metal centers in the preparation of metal-organic compounds. Some of the complexes showed contributions of both cationic and anionic fragments of the starting ion pair, while some others contained only one of these species as ligand. Our review and investigation of compounds revealed that they mainly focused on the concept of supramolecular systems, co-crystallization, stereochemically active lone pairs, coordination polyhedron, mainly on the various interactions involved, including van der Waals, ion pairing, hydrogen bondings, face to face ν-β stackings and edge to face C-Hπ, C-Oπ, N-H3π and SS. These interactions were the most commonly used strategies in the extension of supramolecular structures.

Azaindole hydroxamic acids are potent HIV-1 integrase inhibitors.

Abstract: HIV-1 integrase (IN) is one of three enzymes encoded by the HIV genome and is essential for viral replication. Recently, HIV-1 IN inhibitors have emerged as a new promising class of therapeutics. Herein, we report the discovery of azaindole carboxylic acids and azaindole hydroxamic acids as potent inhibitors of the HIV-1 IN enzyme and their structure−activity relationships. Several 4-fluorobenzyl substituted azaindole hydroxamic acids showed potent antiviral activities in cell-based assays and offered a structurally simple scaffold for the development of novel HIV-1 IN inhibitors.

Crystal engineering with coordination compounds of 2,6-dicarboxy-4-hydroxypyridine and 9-aminoacridine fragments driven by different nature of the face-to-face π⋯π stacking

Abstract: (H9a-Acr)2[Ni(hypydc)2]·4H2O (1), (H9a-Acr)2[Co(hypydc)2]·3H2O (2), (H9a-Acr) [Cr(hypydc)2]·3H2O (3), and (H9a-Acr)2[Cd(hypydc)2]·3H2O (4) compounds (H2hypydc = 2,6-dicarboxy-4-hydroxypyridine or chelidamic acid; 9a-Acr = 9-aminoacridine) were synthesized via proton transfer and characterised by elemental analysis, IR spectroscopy, and single crystal X-ray diffraction techniques. Thermogravimetric analysis (TGA) was carried out on compounds 1 and 2. Compounds 1–4 have distorted octahedral geometries with two hypydc2− ions coordinated as tridentate ligands to each metal ion through one oxygen atom of each carboxylate group and the nitrogen atom of the pyridine ring. In the compounds, strong hydrogen bonds between anionic, cationic, and water fragments and especially the different natures of the π+⋯π− and π−⋯π− stacking interactions play important roles in the construction of three-dimensional supramolecular frameworks which have been analysed in detail. The smaller trans N–M–N angle observed in 3 as compared with the others has been analysed using DFT calculations. Solution studies have also been performed to understand the behaviour of the ternary systems Mn+–H2hypydc–9a-Acr in aqueous solution.

Chromium(III) and Calcium(II) complexes obtained from dipicolinic acid: Synthesis, characterization, X-Ray crystal structure and solution studies

Abstract: The Cr(III) and Ca(II) complexes (dmpH)[Cr(pydc)2]•H2O (1) and [Ca2(pydc)2(H2O)6].2pydcH2 (2) were synthesized by reaction of 2,9-dimethyl-1,10-phenanthroline (dmp) and pyridine-2,6-dicarboxylic acid (pydcH2) with Cr(NO3)3 and Ca(NO3)2, respectively, and characterized using IR spectroscopy, single crystal X-ray diffraction method and solution studies. The space group and crystal system of these two compounds are P2 1/c and monoclinic. The crystal dimensions are a = 9.785(3) A, b = 25.671(4) A, c = 9.3402(16) A, β = 90.790(17)° for (1) and a = 9.1319(4) A, b = 14.8430(8) A, c = 12.2449(7) A, β = 98.227(5)° for (2). In complex (1), a water molecule presents in the crystal packing, linking the anionic and cationic fragments together by hydrogen bonding and thus increases the stabilization of crystal lattices. In complex (2), the coordinated water molecules relate each dimer to adjacent dimers forming infinite molecular ribbons by strong hydrogen bondings. Hydrogen bonding and ion pairing play an important role in stabilizing these crystals. The complexation reactions of pydc, dmp and pydc+dmp with Cr3+ and Ca2+ ions in aqueous solution were investigated by potentiometric pH titrations and the equilibrium constants for all major complexes formed were evaluated.