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Dive into the research topics where Mohamed A.S. Goher is active.

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Featured researches published by Mohamed A.S. Goher.


Chemistry: A European Journal | 2000

Synthesis, Structural Characterisation, and Monte Carlo Simulation of the Magnetic Properties of the 3D-Stacked Honeycomb Csn[{Mn(N3)3}n] and the Irregular Double Chain [{N(C2H5)4}n][{Mn2(N3)5(H2O)}n]

Mohamed A.S. Goher; Joan Cano; Yves Journaux; Morsy A. M. Abu-Youssef; Franz A. Mautner; Albert Escuer; Ramon Vicente

Two new polymeric manganese-azido systems with formula Cs(n)-[[Mn(N3)3]n] (1) and [[N(C2H5)4]n][[Mn2-(N3)5(H2O)]n] (2) were synthesised and structurally characterised. Compound 1 crystallises in the P2(1)/n group and consists of a three-dimensional system with end-to-end and end-on azido bridges with the caesium atoms in the holes of the net. Magnetically, compound 1 is a rare case of a three-dimensional network with alternate ferro-antiferromagnetic interactions. Compound 2 crystallises in the P1 group and consists of double chains of manganese atoms bridged by end-on and, the exceptional, (mu-1,1,1)-azido bridges. Magnetically, compound 2 shows net ferromagnetic behaviour. Exact fit of the magnetic data was performed for the two compounds by means of Monte Carlo simulations based on the Metropolis algorithm on sets of 10 x 10 x 10 (1) and 1 x 1 x 320 (2) S = 5/2 classical spin centres.


Inorganica Chimica Acta | 1985

Synthesis and characterization of a 3:2 complex of copper(II) azide with 2-benzoylpyridine: a polymeric structure containing an end-on triply bridging azido ligand

Mohamed A.S. Goher; Thomas C. W. Mak

Abstract A 3:2 complex of copper(II) azide with 2-benzoylpyridine was synthesized and shown by X-ray cyratallography to be polymeric. The compound crystallizes in space group Pbca , with a = 14.803(3), b = 11.282(2), c = 39.31(1) A, and Z = 8. The structure was refined to R F = 0.079 for 2736 observed Mokα diffractometer data. The bidentate organic ligands each coordinate to a Cu(II) atom to form a chelate ring, and all six independent azido groups serve to bridge neighboring metal centers [at CuN bond distances of 1.975(9)–2.386(9) A] in the μ(1,1) mode, yielding infinite composite chains which pack laterally to constitute a polymeric crystal structure. The bridging N atom of one azilo group forms in additional long bond of 2.627(9) A with a third Cu(II) atom, thereby furnishing a rate example of pyramidal μ(1,1,1), end-on tridentate, azide coordination.


Inorganica Chimica Acta | 1984

Preparation and structural characterization of Di-μ-azido-bis[azido(2-aminopyridine)-aquo]dicopper(II), [Cu(2-ampy)(N3)2(H2O)]2

Mohamed A.S. Goher; Thomas C. W. Mak

Abstract Di-μ-azido-bis[azido(2-aminopyridine)aquo]dicopper(II), [Cu(2-ampy)(N3)2(H2O)]2, was synthesized and characterized by X-ray crystallography. The crystals are triclinic, space group P 1 , with a = 7.142(1), b = 7.812(1), c = 9.727(1) A, a = 96.52(1), β = 95.52(1), γ = 113.47(1)°, and Z = 1. The structure was refined to RF = 0.030 for 1960 observed MoKα diffractometer data. The dimeric molecule, which possesses a crystallographic inversion center, contains both terminal and μ(1)-bridging azido groups. Each copper(II) atom is further coordinated by a 2-aminopyridine ligand (via its ring N atom) and a water molecule to give a distorted square pyramid, with the metal atom raised by 0.17 A above the N4 basal plane [CuN (ring) = 2.001(2), CuN (azide) = 1.962(3)–2.018(2) A] towards the apical aquo ligand [CuO = 2.371(2) A]. Each water molecule forms an intramolecular O⋯HN (amine) acceptor hydrogen bond, and is linked by two OH⋯N (terminal azide) intermolecular donor hydrogen bonds to adjacent dimeric complexes to yield a layer structure parallel to (001). Infrared and electronic spectral data are presented and discussed.


Polyhedron | 2003

Two new polymeric cadmium(II) complexes containing end-to-end bridging azido or thiocyanato ligands with different topologies

Mohamed A.S. Goher; Franz A. Mautner; Afaf K. Hafez; Morsy A. M. Abu-Youssef; Christian Gspan; Ahmed M.A. Badr

Abstract Two new polymeric cadmium(II) complexes; [Cd(3,5-DMP)2(N3)2] (1) and [Cd(4-Brpy)2(NCS)2] (2), where 3,5-DMP=3,5-dimethylpyridine and 4-Brpy=4-bromopyridine, have been synthesized and characterized. IR spectral data suggest end-to-end bridging azido and thiocyanato ligands. X-ray crystal structure determination has shown the 1-D complex 1 to contain each cadmium octahedrally coordinated by two double μ(1,3)-bridging azides and the other two sites are occupied by two pyridine ligands in a cis-arrangement. The CdCd distances in the Cd2(N3)2 eight membered rings are 5.142(2) and 5.152(2) A, the azide ligands are almost symmetrical and linear [NN distances: 1.167(5)–1.182(5) A; ∠NNN=176.7(4)° and 177.6(4)°]. In complex 2 each octahedrally cadmium atom is coordinated by two trans pyridine ligands and two trans nitrogen or sulfur atoms from four μ(N,S) bridging thiocyanato groups. The other end atoms of these four thiocyanato ligands bind four different cadmium atoms giving a 2-D layer structure.


Inorganica Chimica Acta | 1986

Synthesis and structural determination of di-μ(1,1)-azido-bis [azido(2-benzoyl-pyridine)] dicopper(II) and catena-di-μ(1,3)-azido[di-μ(1,1)-azido-bis(ethyl nicotinate)dicopper(II)] ☆

Thomas C. W. Mak; Mohamed A.S. Goher

Abstract Two 1:1 mixed ligand complexes of copper(II) azide with substituted pyridines, namely di-μ(1,1)- azido-bis[azido(2-benzoylpyridine)]dicopper(II) (1) and catena-di-μ(1,3)-azido-[di-μ(1,1)-azido-bis(ethyl nicotinate)dicopper(II)] (2), have been synthesized and characterized by X-ray crystallography. Crystal data: 1, C24H18N14Cu2O2:, space group P 1 , a = 7.471(2), b=10.477(3), c=9.389(3) A, α = 100.77(2), β = 109.83(2), γ=82.21(2)°, Z=1, and RF=0.036 for 2035 observed Mo Kα data; 2, C8H9-N7CuO2, space group P21/c, a=9.961(2), b = 5.306(1), c=22.621(4) A, β=96.81(2)°, Z=4, and RF=0.044 for 869 observed Mo Kα data. In the centrosymmetric binuclear molecule 1, the Cu(II) atom has distorted square pyramidal coordination geometry involving a bidentate 2-Bzpy ligand, with each μ(1,1) bridging N atom serving simultaneously as a basal ligand to one metal atom and as a distal axial ligand to the other. The polymeric complex 2 features monodentate Et-nic ligands, centrosymmetric di-μ(1,1) azido bridged Cu2N2 rings, distorted square pyramidal Cu(II) coordination geometry, and di-μ(1,3) azido bridges which link the centrosymmetric binuclear Cu2(Et-nic)2(N3)2 moieties into infinite chains parallel to the b axis.


Journal of The Chemical Society-dalton Transactions | 2002

Synthesis and crystal structure of three new 2D polymeric cadmium(II) complexes of some pyridine derivatives with different cadmium(II)–azide topologies

Mohamed A.S. Goher; Franz A. Mautner; Morsy A. M. Abu-Youssef; Afaf K. Hafez; Ahmed M.A. Badr

Three new polymeric complexes [Cd(2-Acpy)(N3)2]n1, [Cd(4-Acpy)2(N3)2]n2 and [Cd3(4-Brpy)4(N3)6]n3 (2-Acpy = 2-acetylpyridine, 4-Acpy = 4-acetylpyridine, and 4-Brpy = 4-bromopyridine) have been synthesized and characterized by single crystal X-ray diffraction. The coordination environment of the cadmium atom in all the complexes is distorted octahedral with two-dimensional polynuclear layers. The cadmium atoms are linked by both μ-1,1 and μ-1,3 in 1, by only μ-1,3 in 2 and by μ-1,1 and μ-1,1,3 azide bridges in 3 giving different cadmium(II)–azide topologies.


Polyhedron | 2000

Synthesis, structural and spectroscopic study of polymeric copper(I) thiocyanato complexes [Cu(NCS)L]n (L=methyl nicotinate and ethyl nicotinate) and [HL][Cu(NCS)2] (HL=H-ethyl isonicotinate)

Mohamed A.S. Goher; Qing-Chuan Yang; Thomas C. W. Mak

Abstract Three new copper(I) thiocyanato complexes [Cu(NCS)L]n (L=methyl nicotinate 1, ethyl nicotinate 2), and [HL][Cu(NCS)2] (HL=H-ethyl isonicotinate 3), have been prepared and characterized by spectroscopic and crystallographic methods. All three complexes display MLCT transitions in the visible region, as well as visible solid state emission spectra at room temperature. Their IR spectra are measured and discussed. In the structure of 1 each copper atom links two S atoms from two μ-S,S,N thiocyanato ligands and two nitrogen atoms from a pyridine nucleus and from a third μ-S,S,N thiocyanate group; the two S atoms bind another copper atom forming a Cu2S2 cyclic unit. The ladder propagates along the a axis of the unit cell. The structure of 2 features CuS2N2 coordination with approximate tetrahedral environment, μ-S,S,N bridging thiocyanate groups giving rise to corrugated layers at y=1/4. Complex 3 consists of an N-protonated ethyl isonicotinate cation and a polymeric [Cu(NCS)2]− anion. Each trigonal planar copper atom in the anion is coordinated by two S atoms from a μ-S,N thiocyanate bridge and a terminal S-thiocyanate group, and the third site is occupied by the end nitrogen of a μ-S,N thiocyanate bridge. The terminal NCS group forms a hydrogen bond of the type N–H⋯N with an N–H group of the [HL]+ cation. The planar ribbon which runs in the a direction is further stabilized by N–H⋯O hydrogen bonds.


Polyhedron | 1996

Synthesis, spectral and structural characterization of a monomeric chloro complex of Zinc(II) with picolinic acid, [Zn(C5H4NCO2H)(C5H4NCO2)Cl]

Mohamed A.S. Goher; Morsy A. M. Abu-Youssef; Franz A. Mautner

Abstract The title compound of zinc(II) and picolinic acid was synthesized and characterized by X-ray crystallographic and spectroscopic methods. In the structure of [Zn(C5H4NCO2H)(C5H4NCO2)Cl], each zinc atom is coordinated by two nitrogen atoms at ZnN distances of 2.040(8) A and two oxygen atoms, O(1), at ZnO bond lengths of 2.152(5) A, belonging to two picolinate ligands. Coordination number five of the zinc atom is completed by a ZnCl bond [2.221 (3) A]. The O(2)⋯O(2) separation between non-coordinated picolinate oxygen atoms of adjacent polyhedra is 2.41 (1) A. The IR and Raman spectral results confirm the existence of neutral picolinic acid as well as the picolinate anion.


Polyhedron | 2002

A new series of 1D polymeric nickel(II) complex cations of pyridine derivative ligands with a single μ-1,3 azide bridge and X-ray crystal structure and magnetic properties of polymeric {[Ni(4-ethylpyridine)4(N3)n](PF6)n}

Mohamed A.S. Goher; Albert Escuer; Frank A Mautner; Najeeb A. Al-Salem

A new series of polymeric nickel(II) complex cations of the formula [NiL 4 (N 3 )](PF 6 ), for L = pyridine, 4-methyl-, 4-ethyl-, 3-chloro-, 3-bromo- and 3-hydroxy-pyridine, have been prepared and characterized. Solid state electronic spectra suggest six-coordinate nickel(II) in all complexes. IR spectral results reveal the existence of symmetrical azido ligands and PF 6 - counter ions in these complexes. X-ray crystal structure determination has shown the complex for L = 4-ethylpyridine (1) to contain a polymeric [NiL 4 (N 3 )] + cation and PF 6 -, anions. In the cation each nickel(II) atom is coordinated by four nitrogen atoms from the pyridine ligands and two nitrogen atoms each from a μ-1,3 bridging azide giving rise to ID polymeric chains of six-coordinate Ni(II) polyhedra. The azide ligand is symmetrical [N 1 - N 2 =N 2 -N 3 = 1.152 and N 1 -N 2 = 1.164, N 2 -N 3 = 1.162 A] and linear [NNN angles =178° and 180°] within the experimental error. The magnetic susceptibilities of 1 in the range of 2-300 K, have been measured and discussed.


Polyhedron | 1992

Spectral and X-ray structure determination of two polymeric complexes of copper(II) azide with 3-picoline and 2-bromopyridine: Cu(3-picoline)2(N3)2 and Cu(2-bromopyridine)(N3)2

Franz A. Mautner; Mohamed A.S. Goher

Abstract Two mixed-ligand complexes of copper(II) azide with substituted pyridines, namely catena-di-μ(1,3)-azido[di-μ(1,1)-azido-tetrakis(3-picoline)dicopper(II)] (1) and catena-di-μ(1,1)-azido[di-μ(1,1)-azido-bis(2-bromopyridine)dicopper(II)] (2), have been synthesized and characterized by X-ray crystallography. The 1:2 polymeric complex 1 contains two crystallographically independent copper octahedra. Cu(1) occupies the special position at the inversion centre, and both copper centres have a (4+2) coordination with four short bonds [CuN from 1.970 to 2.030 A] and two long bonds [CuN from 2.625 to 2.679 A]. Cu(1) and Cu(2) are linked via two μ(1,3)-azido ligands, whereas azido groups of the type μ(1,1) bridge the adjacent Cu(2)Cu(2) centres. In the polymeric 1:1 complex 2 of 2-bromopyridine the copper(II) has distorted square pyramidal coordination geometry, where both azido ligands function as μ(1,1) bridges to form chains along the crystallographic a-axis. The IR and electronic spectra are given and discussed.

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Franz A. Mautner

Graz University of Technology

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Thomas C. W. Mak

The Chinese University of Hong Kong

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Christian Gspan

Graz University of Technology

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