Moustafa Sh. Ibrahim

Paramagnetic charge-transfer guest–host coordination polymers. Thiophene compounds encapsulated within the channels of the three-dimensional coordination polymers [(R3Sn)3Fe(CN)6] n , R = Me, n-Bu or Ph

Various thiophene compounds have been shown to be encapsulated and partly oxidized within the channels of the three-dimensional (3D) host coordination polymers [(R3Sn)3Fe(CN)6]n (R = Me, n-Bu or Ph) to give guest–host encapsulated systems. The structure and physical properties of these systems were studied by X-ray powder diffraction, i.r., u.v.–vis., e.p.r. spectra and magnetic measurements. Thiophene compounds do not polymerize within the channels of the host, but rather give paramagnetic charge-transfer guest–host systems.

Supramolecular host-guest systems as frameworks for excitation energy transfer

The antenna behavior of rhodamine 6G and methylene blue loaded novel host supramolecular frameworks is investigated. The geometrical constraints of these supramolecular hosts allows the cationic dye molecules encapsulating within the parallel channels to form novel host-guest systems. The cationic dyes are close together that self-quenching of electronic excitation energy can occur. The excitation energy transfer occurs from rhodamine 6G as a donor (D) to methylene blue as an acceptor (A) within supramolecular systems filled with a mixture of both dyes.

Supramolecular Self Assembly of [Cu(CN)4]3− Ions with Cationic {Ph3Sn+} Units in the Presence of Neutral Bidentate Ligands

The supramolecular interplay of the Ph 3 Sn+ unit and the [Cu(CN) 4 ]3− ion with either 4,4′-bipyridine (bpy), trans-1,2-bis(4-pyridyl)ethene (tbpe), 1,2-bis(4-pyridyl)ethane (bpe), pyrazine (pyz), or methylpyrazine (mepyz) as bidentate ligands in presence of H 2 O has been investigated for the first time. The products obtained have the general formula [(Ph 3 Sn) 3 Cu(CN)4·L·XH2O], where L is a bidentate ligand and X = 0–2. H 2 O molecules are usually coordinated to tin atoms and are involved in two significant O─H─N hydrogen bonds, wherein the nitrogen atoms belong either to the bidentate ligand or the M-coordinated cyanide ligands. The structures of these supramolecular coordination polymers were investigated by elemental analysis, X-ray powder diffraction, and IR, mass, and NMR spectra.

N,O‐Bidentate Schiff Bases as Novel Ligands and Self‐Assembled Three‐Dimensional Supramolecular Complex of Silver(I): Syntheses and Characterization

Abstract Three novel N,O‐bidentate Schiff bases H2L1, H2L2, and H2L3 have been prepared and investigated. H2L1 underwent self‐assembly with silver(I) nitrate forming the supramolecular complex [Ag2(H2L1)3] n (NO3)2n , whereas H2L2 and H2L3 do not form supramolecular complexes due to the chain length of the bidentate Schiff bases, which prevent Ag–N interactions. The results indicate the effect of the chain length of diamine, the presence of active phenol group, and the arrangement of silver(I) interactions on the formation of three‐dimensional (3D) supramolecular complex.

Oxidation of a three-dimensional polymeric iron(II) complex with sodium nitrite in acidic medium

Oxidation of the water-insoluble polymeric iron(II) complex, [(Me3Sn)4FeII(CN)6]n, with NaNO2 in an acidic medium was followed by monitoring the increase of absorbance of the water-soluble polymeric iron(III) complex product at 419 nm. The reaction is first order in polymer, oxidant and ethanoic acid. Experiments over the temperature range 25–40 °C allowed calculation of the activation parameters. The reaction between the solid polymeric iron(II) complex and NO2 has been investigated by i.r., electronic-reflectance, X-ray powder diffraction spectra and magnetic measurements. A mechanism involving electron-transfer is proposed.

Three dimensional tris[triorganotin(IV)]hexacyanoiron(III) polymeric complexes as oxidising agents

The oxidation of N2H4 by tris[triorganotin(IV)]hexacyanoiron(III) polymer complexes has been studied spectrophotometrically. The oxidation rate is first order in both complex and N2H4 and the rate constant increases with increasing pH. Experiments over the temperature range (15–30 °C) allowed calculation of the activation parameters. An outer-sphere mechanism involving a rate-determining one-electron transfer is proposed. In addition, the products of the solid reactions between the iron(III) polymeric complexes and N2H4 were investigated by i.r., u.v. reflectance, X-ray powder diffraction, e.p.r. spectra and magnetic measurements.

NOVEL SUPRAMOLECULAR DERIVATIVES CONTAINING TWO R3Sn+ (R = Me, n-Bu, or Ph) CONNECTING UNITS: THE FORMATION OF NOVEL HOST–GUEST SYSTEMS BY THE FACILE ENCAPSULATION OF GUEST THIOPHENE COMPOUNDS

New supramolecular complexes [(Me 3 Sn)(Ph 3 Sn) 2 Fe(CN) 6 ] (I) and [(n-Bu 3 Sn)(Ph 3 Sn) 2 Fe(CN) 6 ] (II) are readily accessible by straightforward self-assembly of [Fe(CN) 6 ] 3− and hydrated R 3 Sn+/R′ 3 Sn + ions (R = Ph, and R′ = Me or n-Bu). The structural characterization of (I) and (II) is compared with well-documented supramolecular complex containing only Ph 3 Sn + unit, [(Ph 3 Sn) 3 Fe(CN) 6 ]. These novel compounds have wide internal cavities capable of encapsulating voluminous organic compounds, and they behave as host acceptors forming charge transfer complexes (CTC). Thiophene compounds acting as guest donor species are encapsulated within the cavities of the three-dimensional (3D) supramolecular hosts. The structure and physical properties of these hosts and host–guest systems were studied by X-ray powder diffraction, IR, UV/Vis., and magnetic measurements.