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trans-Dichloridobis[diphenyl(4-vinylphenyl) phosphane-kP]palladium(II)

- Meijboom, Reinout

Di-μ-iodido-bis{[dicyclohexyl(phenyl)-phosphine-κP](pyridine-κN)silver(I)}

- Omondi, Bernard, Meijboom, Reinout

N-Benzyl-P-(2-ethylphenyl)-P-phenylphosphinic amide

- Kinfe, Henok H., Hamese, Augustine, Hughes, Tanya, Omondi, Bernard

Tetra-µ-acetato-κ⁸O:O'-bis[(3,5-dimethyl-1H-pyrazole-κN²)copper(II)]

- Van Wyk, Juanita, Omondi, Bernard, Darkwa, James

  • Authors: Van Wyk, Juanita , Omondi, Bernard , Darkwa, James
  • Date: 2011
  • Subjects: X-ray crystallography , Crystallography , Pyrazolyl ligands , Palladium compounds
  • Type: Article
  • Identifier: uj:5908 , ISSN 1600-5368 , http://hdl.handle.net/10210/8067
  • Description: Pyrazolyl ligands containing a carbonyl linker has been utilized to prepare a number of coordination compounds with palladium salts (Guzei et al., 2003; Mohlala et al., 2005, Ojwach et al., 2005). In these compounds the pyrazolyl carbonyl moiety appear to be robust enough to avoid hydrolysis. However in a few instances the presence of metal ions like Cu(II) (Deka et al., 2006) and Pd(II) (Nelana et al., 2008) appear to catalyze the hydrolysis of the benzoyl fragments. We have observed similar hydrolysis when reacting copper(II) acetate with (3,5-dimethyl-pyrazol-1-yl)-o-benzoyl-methane. The title compound formed from this reaction is the subject of this report. The half "solvent" molecule excluded from the structure had a total number of 30.7 electrons which is approximately half the total number of electrons that acetophenone has. Compound (I) crystallizes with two half molecules in the assymetric unit. The compound is dinuclear with each of the Cu atoms coordinated to four O atoms and a N atom from the pyrazole ligand. The O atoms are from acetate ions, all in the equatorial positions of a slightly distorted octahedral geometry around the Cu atoms. The N atom is bound trans to the Cu—Cu vector completing a the distorted octahedral geometry as axial ligands. The crystal structure of (I) is composed of two N—H···O hydrogen bonded chains (Table 1) that extend in the crystallographic b axis (Fig. 2).
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Butane-1,4-diammonium bis(perchlorate)

- Arderne, Charmaine, Kruger, Gert J.

Bis[dicyclohexyl(phenyl)phosphane-κP]- silver(I) perchlorate dichloromethane monosolvate

- Munyaneza, Apollinaire, Meijboom, Reinout, Omondi, Bernard

Bis(2-methoxyphenyl)(phenyl)phosphine selenide

- Muller, Alfred

trans-Carbonylchloridobis[tris(4-chlorophenyl) phosphane]rhodium(I) acetone monosolvate

- Burgoyne, Andrew R., Meijboom, Reinout, Muller, Alfred, Omondi, Bernard O.

Bis(dicyclohexylphenylphosphine)- silver(I) nitrate

- Burgoyne, Andrew R., Meijboom, Reinout, Muller, Alfred, Omondi, Bernard

Di-μ-thiocyanato-bis[bis(tri-p-tolylphosphine) silver(I)] 0.35-hydrate

- Khumalo, Nozipho M., Meijboom, Reinout, Muller, Alfred, Omondi, Bernard

Characterisation by X-ray diffraction of naturally occurring polycrystalline diamond samples from different origins

- Moipolai, Tshegofatso Bridgette

  • Authors: Moipolai, Tshegofatso Bridgette
  • Date: 2015-11-12
  • Subjects: X-ray crystallography , X-rays - Diffraction , Photonic crystals , Crystals - Structure
  • Type: Thesis
  • Identifier: uj:14559 , http://hdl.handle.net/10210/15092
  • Description: M.Phil. (Energy Studies) , Non-destructive investigations of unusual natural polycrystalline diamond samples are reported. The samples originate from various international locations discovered in soils and sediments and may have been formed by di erent mechanisms which are the subject of debate. Analysis techniques include scanning electron microscopy, with energy dispersive spectroscopy and X-ray di raction. Sample composition, structure and surface stresses were investigated. The samples (two Egyptian nodules, two Brazillian carbonados, two Venetian ballas diamonds and a polycrystalline diamond compact sample consisting of a polycrystalline diamond layer sintered onto a Co-cemented tungsten carbide support) are cubic diamonds, with varying amounts of minority phases. In most cases the minority phases could not be identi ed unambiguously due to their low intensities and the overlap of Bragg peaks. The Egyptian nodule samples in particular showed a large presence of oxygen that could not be linked to speci c metal oxides. The Ballas samples had the lowest impurity content. Using a Rietveld based quanti cation analysis, the crystalline cubic diamond contents were determined respectively as 99 wt.%, 98 wt.% and 76 wt.% in the Ballas, Brazilian carbonado and Egyptian nodule samples. A signi cant result from this study is the substantial inhomogeneous peak broadening observed in the X-ray diffraction patterns of the Egyptian samples. This is indicative of the presence of nano-crystalline diamond grains in addition to substantial mechanical deformation with extensive accumulation of dislocations and crystalline defects. These observations are supportive of a recently proposed impact mechanism for their formation.
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(μ-Ethane-1,2 diamine-κ²N:N’)bis-[dicarbonyl(η⁵-cyclopentadienyl)iron(II)] bis(tetrafluoridoborate)

- M’thiruaine, Cyprian M., Friedrich, Holger B., Changamu, Evans O., Omondi, Bernard

Dichlorido(ɳ4-cycloocta-1,5-diene)-bis(propanenitrile-ĸN)ruthenium(II)

- Chiririwa, Haleden, Meijboom, Reinout

[Bis(pyridin-2-ylmethyl) ether]- trichloridorhodium(III) dichloromethane monosolvate : unusual hydrolysis of the methylene bridge in (pyrazolylmethyl)- pyridine

- Ojwach, Stephen O., Omondi, Bernard, Darkwa, James

2-(Thiophen-2-yl)-N-(4-{(E)-[2-(thiophen- 2-yl)ethyl]iminomethyl}benzylidene)- ethanamine

- Chiririwa, Haleden, Meijboom, Reinout, Omondi, Bernard

Bis(2,4-dimethoxyphenyl)(phenyl)-phosphine selenide

- Muller, Alfred

cis-Dichloridobis[diphenyl(4-vinylphenyl) phosphane-kP]platinum(II)

- Ogutu, Hezron, Meijboom, Reinout

  • Authors: Ogutu, Hezron , Meijboom, Reinout
  • Date: 2011
  • Subjects: X-ray crystallography , Crystallography , Transition metal complexes
  • Type: Article
  • Identifier: uj:5886 , ISSN 1600-5368 , http://hdl.handle.net/10210/8002
  • Description: Transition metal complexes containing phosphine, arsine and stibine ligands are widely being investigated in various fields of organometallic chemistry (Spessard & Miessler, 1996). As part of a systematic investigation involving complexes with the general formula trans/cis-[MX2(L)2] (M = Pt or Pd; X = halogen, Me, Ph; L = group 15 donor ligand), the crystals of the title compound, were obtained. [PtCl2(L)2] (L = tertiary phosphine, arsine or stibine) complexes can conveniently be prepared by the substitution of 1,5-cyclooctadiene (COD) from [PtCl2(COD)]. The title compound, cis-[PtCl2{P(4—H2C=CHC6H4) Ph2}2], crystallizes in the triclinic spacegroup P1, with the Pt atom on a center of symmetry and each pair of equivalent ligands in a cis orientation. The geometry is a slightly distorted square planar and the Pt atom is slightly elevated out of the coordinating atom plane. The two P atoms are closer to each other but away from the two chloride atoms with angles of P1—Pt—P2 = 96.1 (4)° and Cl1—Pt—Cl2 = 87.7 (4)° whereas the P1—Pt—Cl1 is = 175.1 (4)° and that of P1—Pt—Cl2 being 89.6 (4)° The title compound compares well with other closely related PtII complexes from the literature containing two chloro and two tertiary phosphine ligands in a cis geometry. The title compound, containing Pt—Cl bond lengths of 2.3566 (9) and 2.3336 (9) Å and Pt—P bond distances of 2.2489 (9) and 2.2627 (9) Å, fits well into the typical range for complexes of this kind. Notably the title compound did not crystallise as a solvated complex; these type of PtII complexes have a tendency to crystallise as solvates (Meijboom & Omondi, 2011). Large thermal vibrations on the periphery of the molecule results in a badly defined C═C bond length. Disordered modelling resulted in an unstable refinement.
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1,4-Bis[(2-pyridylethyl)iminomethyl]- benzene

- Chiririwa, Haleden, Moss, John R., Su, Hong, Hendricks, Denver, Meijboom, Reinout

3,4,6-Tri-O-acetyl-1,2-[(S)-ethylidene]-β- D-mannopyranose

- Kinfe, Henok H., Makolo, Felix L., Phasha, Zanele, Muller, Alfred

1,5-Anhydro-3,6-di-O-benzyl-2-deoxy- 1,2-C-dichloromethylene-D-glycero-Dgulo- hexitol

- Kinfe, Henok H., Aderibigbe, Blessing A., Muller, Alfred

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