Md. Khayrul Kabir

Synthesis and crystal structure of [Ni{bis(2,5-dihydroxysalicylidene)ethylenediaminato}]: a hydrogen bonded assembly of Ni(II)–salen complex

Abstract The hydrogen bonded assembly of salen type complexes was studied. The nickel(II) complex with N,N′-bis(2,5-dihydroxysalicylidene)ethylenediaminato was synthesized, and structurally characterized. The compound has two hydroxy groups at the both terminals of the tetradentate ligand. One of the two hydroxy groups of the nickel(II) complex forms a hydrogen bond with a coordinating oxygen donor of the adjacent molecule to yield a hydrogen bonded one-dimensional chain. These chains are also associated by π–π interactions with interlocking fashion to produce a two-dimensional structure. The guest ethanol molecules are incorporated between the two-dimensional layers.

The rational syntheses of manganese-chloranilate compounds: crystal structures and magnetic properties

[Mn(CA)(terpy)] n ( 1 ) and {[Mn(CA)(bipym) 0.5 (H 2 O)](H 2 O)(C 2 H 5 OH)} n ( 2 ) (H 2 CA=chloranilic acid, terpy=2,2′:6′,2″-terpyridine and bipym=2,2′-bipyrimidine) have been synthesized and their crystal structures determined by a single-crystal X-ray diffraction. Compound 1 is made up of infinite chains of chloranilate-bridged manganese(II), affording a zig–zag pattern, with terpyridine ligands stacking between the chains. Compound 2 has a novel honeycomb layered structure, where each hexagon consists of six Mn(II) ions, four CA 2− and two bipym ligands. Mn(II) ions in both compounds are unusually hepta-coordinated. Magnetic susceptibility measurements of both compounds show weak antiferromagnetic coupling between the nearest Mn(II) ions.

Novel layered structures constructed from iron-chloranilate compounds

Abstract Novel hydrogen bond-supported intercalation compounds, {(G) m [Fe(CA) 2 (H 2 O) 2 ]} n (CA 2− =chloranilate, G=guest molecules) have been synthesized and characterized. The compound {(Hpy)[Fe(CA) 2 (H 2 O) 2 ](H 2 O)} n (py=pyridine) ( 1 ) crystallizes in the triclinic, space group P 1 (#2), with a =9.537(5), b =13.563(6), c =9.231(4) A, α =107.18(4), β =102.33(4), γ =102.12(4)°, V =1065.9(10) A 3 , and Z =2. Compound {(H 2 bipy)[Fe(CA) 2 (H 2 O) 2 ] 2 (H 2 O) 2 } n (bipy=4,4′-bipyridine) ( 2 ) crystallizes in the triclinic, space group P 1 (#2), with a =9.101(1), b =10.379(1), c =12.802(2) A, α =79.45(1), β =82.67(1), γ =66.32(1)°, V =1086.8(3) A 3 , and Z =1. The structure of 1 consists of mononuclear [Fe(CA) 2 (H 2 O) 2 ] − anions, Hpy + cations and uncoordinated water molecules. Four oxygen atoms of two CA 2− anions and two oxygen atoms from two water molecules are coordinated to the iron ion making anionic building blocks of the host layer. The compound of 2 contains the similar monomeric building blocks, H 2 bipy 2+ cations and uncoordinated water molecules. In both the compounds the coordination geometry of the building blocks are distorted octahedron, where two water molecules sit on the trans position in 1 and on the cis position in 2 . In compound 1 the [Fe(CA) 2 (H 2 O) 2 ] − anions make a two-dimensional (2-D) layer supported by hydrogen bonds. Hpy + ions are included in between the layers of 1 supported by hydrogen-bonding and electrostatic interaction with the host layers. In compound 2 the coordinated chloranilate rings of [Fe(CA) 2 (H 2 O) 2 ] − anions are stacked upon each other and make a layer with the help of hydrogen bonds. H 2 bipy 2+ cations are included in between the layers supported by hydrogen bonding, electrostatic and stacking interaction with coordinated CA 2− ions. The 57 Fe Mossbauer spectra of the compounds show that the oxidation state of iron is 3 with IS=0.41 ( 1 ) and 0.39 mm s −1 ( 2 ); QS=0.83 ( 1 ) and 1.29 mm s −1 ( 2 ) at 296 K, respectively. Compound 2 shows weak antiferromagnetic interaction over the crystal ( θ =−2.3 K).

Proton-transfer-mediated crystal engineering using 1,4,5,6-tetrahydro-5,6-dioxo-2,3-pyrazinedicarbonitrile with 4,4′-bipyridine

The crystal structure of a salt [Hbpy][Htdpd] (1) (bpy = 4,4′-bipyridine, H2tdpd = 1,4,5,6-tetrahydro-5,6-dioxo-2,3-pyrazinedicarbonitrile) is reported; the supramolecular structure is rationally designed via hydrogen bonding interactions.

A new nano-scale ferrocene assembly supported by a supercubane framework

Six ferrocenedicarboxylate units were supported by a supercubane framework to create a new nano-scale ferrocene assembly with a spherical motif, whose structure and redox properties were characterized.

Iron-Chloranilate Intercalation Compounds: Synthesis, Crystal Structures, and Thermal Properties

Abstract Hydrogen bond supported new iron-chloranilate assemblies, {(Hpy)[Fe(CA)2(H2O)2](H2O)}n (py = pyridine, H2CA = chloranilic acid, C6H2O4Cl2) (1), and [(phz)2[Fe(CA)2(H2O)2](H2O)2]n (phz = phenazine, C12H8N2) (2) have been synthesized and characterized. Compound 2 crystallizes in the monoclinic, space group C2/m (#12), with a= 29.135(6) Å, b= 16.886(6) Å, c = 15.017(5) Å, ß = 165.907(1)°, V= 1798(2) Å3, Z = 2. In both the compounds two chloranilate dianions and two water molecules are coordinated to the iron ion making anionic monomers [Fe(CA)2(H2O)2]−, which are the building blocks of the compounds. The coordination environment around the iron ion in the building block is a distorted octahedron, where two water molecules sit on the trans position to each other. [Fe(CA)2(H2O)2]− anions form common layer structures, supported by hydrogen bonds. Hpy+ are intercalated in between the layers of 1 by electrostatic and hydrogen bonding interactions and phz are intercalated in that of 2 by electrostatic interactions. DSC traces of 1 show anomaly at 174 K, indicating phase transition in the compound.

Crystal Structure and Magnetic Property of Cobalt(II) Assembled Compound, {[Co(CA)(bipym)](H2O)2}n (H2CA = chloranilic acid, bipym = 2,2′-bipyrimidine)

Abstract Cobalt(II) assembled complex compound, {[Co(CA)(bipym)](H2O)2}n(H2CA = chloranilie acid, bipym = 2,2′-bipyrimidine) (1) has been synthesized and structurally characterized by single-crystal X-ray diffraction. Compound 1 crystalizes in the monoclinic, space group C2/c(#15), with a = 16.652(4) Å, b = 11.163(3) Å, c = 10.081(3) Å, β = 116.12(2)°, V = 1682.4(7) Å3, Z = 4. The bipym ligands bridge the cobalt centers in bis-bidentate fashion and make zigzag chains. The chains form layer structures by stacking interaction and hydrogen bonding interaction with the help of interstitial water molecules. The temperature dependence of the magnetic susceptibility of 1 shows intramolecular antiferromagnetic interaction with θ = - 39.7 K.