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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Synthesis and Characterization of 2,2-cis-[Rh2(NPhCOCH3)4]•NCC6H4R where R = H, 2-CH3, 3-CH3, 4-CH3 and [Rh2(O2CCH3)(NPhCOCF3)3]

Quarshie, Fredricka F 01 December 2013 (has links)
Five novel compounds were synthesized and characterized. Crystal structures were determined using Rigaku Mercury 375/MCCD(XtaLAB mini) diffractometer with graphite monochromated MoKα radiation. The crystal structures of [Rh2(NPhCOCH3)4•xNCC6H4R where x = 1 or 2 and R=H, 2-CH3,3-CH3 and 4-CH3 were solved to an R1 value of less than 5 (R1= Σ||Fo| - |Fc|| / Σ |Fo|). In each of the nitrile complexes, the rhodium is five or six coordinate and possesses pseudo D4h symmetry. The complexes were also characterized by NMR and IR spectroscopy. [Rh2(CO2CCH3)(PhCOCF3)3] was also synthesized. In this complex, each rhodium atom is six coordinate, thus each rhodium is in an octahedral environment. Details of each synthesized complex are discussed.
2

Synthesis and Characterization of Imidazolo 3,1- Tetrakis (N-phenylacetamidato) Dirhodium (II) and a Crystallographic Study of a Copper and Two Molybdenum Model Cofactors

Thompson, Gabriel I.G. 01 August 2016 (has links)
Imidazole was reacted with 3,1-tetrakis (N-phenlyacetamidato) dirhodium (II) to explore the chemistry of asymmetric dirhodium catalysts. The imidazolo 3,1-tetrakis (Nphenlyacetamidato) dirhodium (II) complex was synthesized and then characterized by Nuclear Magnetic Resonance and Ultraviolet-Visible spectroscopies as well as by single crystal X-ray Diffraction. Additionally, one copper and two molybdenum model cofactors were characterized by XRD to better understand their structure/function relationships. NMR results gave evidence of the formation of the 3,1-imidazole complex, and UV-Vis indicated that even in large excess imidazole was coordinated only to one axial site. The structure of the 3,1-imidazole complex was confirmed by XRD with the following refinement indicators: R1: 3.97%, wR2: 9.27%, GooF: 1.036. Model cofactors were also characterized by XRD and resulted in the following refinement indicators for Mo-1: R1: 4.27%, wR2: 9.15%, GooF: 1.074; for Cu-1: R1: 10.10%, wR2: 22.60%, GooF: 0.991, and for Mo-2: R1: 17.75%, wR2: 46.08%, GooF: 0.954.
3

Synthesis and Characterization of Five New Tetrakis(N-phenylacetamidato) Dirhodium(II) Amine Complexes and One Molybdenum Cofactor Described Crystallographically

Harris, Cragin K 01 May 2015 (has links)
Six new crystal structures were determined using a Rigaku Mercurcy 375/MCCD(XtaLab mini) diffractometer. The structure of a molybdenum cofactor was solved resulting in an R1 (R1 = Σ ||Fo| - |Fc|| / Σ |Fo|) of 3.61% despite the presence of a disordered DMSO molecule. New Tetrakis(N-phenylacetamidato) Dirhodium(II) complexes were synthesized and characterized. Two 2,2-cis-[Rh2(NPhCOCH3)4]•(C3H4N2)x where x= 1 or 2 were successfully crystallized and solved with R1 values below 5%. Additional studies were conducted via NMR to observe formation of both products. Three potential catalysts were synthesized starting with 3,1-[Rh2(NPhCOCH3)4]. The resulting compounds were a mono adduct 3,1-[Rh2(NPhCOCH3)4]•(C3H4N2), and two dimer of dimers complexes with amine bridges 3,1-[Rh2(NPhCOCH3)4]2•(C8H6N2) and 3,1-[Rh2(NPhCOCH3)4]2•(C10H8N2). All three complexes were crystallized and solved with R1 values less than 10%. Additional NMR studies were conducted to elucidate solid and solution phase structures and to determine the possibility of additional amine bonds forming.
4

X-ray crystal structures of: [Rh2(N-{2,4,6-CH3}C6H2)COCH3)4]•2NCC6H4 AND Ba1.5[Fe(C10H13N2O7)][Co(CN)6]•9H2O; two crystallographic challenges

Kpogo, Kenneth K 01 August 2013 (has links)
The novel compound, [Rh2(N-{2,4,6-CH3}C6H2)COCH3)4] was synthesized. Crystal structures of [Rh2(N-{2,4,6-CH3}C6H2)COCH3)4]·2NCC6H5 and Ba1.5[Fe(C10H13N2O7)][Co(CN)6]·9H2O were determined employing a Rigaku Mercury375R/M CCD (XtaLAB mini) diffractometer with graphite monochromated Mo-Kα radiation. For [Rh2(N-{2,4,6-CH3}C6H2)COCH3)4]·2NCC6H5, the space group was P-421c(#114) with unit cell dimensions: a =11.0169(14)Å, c =21.499(3)Å, V = 2609.4(6)Å3. Each rhodium had approximately octahedral coordination and was bound to another rhodium atom, two nitrogens (trans to each other), two oxygens (trans to each other), and one benzonitrile nitrogen (trans to rhodium). For Ba1.5[Fe(C10H13N2O7)][Co(CN)6]·9H2O the space group was: P-1(#2) with unit cell dimensions: a=13.634Å, b=13.768Å, c=17.254Å and α=84.795°, β=87.863°, γ=78.908°, V=3164.5Å3. The iron atom (nearly octahedral) was coordinated to one chelating ligand (derived from ethylenediaminetetraacetic acid) and the nitrogen of a cyanide ligand. The carbon of the cyanide ligand was bound to cobalt (octahedral). Thus, the cyanide ligand serves as a bridge between the two metals.

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