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Synthesis, spectroscopic and structural elucidation of discrete, one dimensional and two dimensional coordination compounds of 1,3,5-triaza-7-phosphaadamantane, N-methyl-1,3,5-triaza-7-phosphaadamantane and silver(I).

dc.contributor.advisorOwaga, Bernard Omondi.
dc.contributor.authorZamisa, Sizwe Joshua.
dc.descriptionM. Sc. University of KwaZulu-Natal, Durban 2014.en
dc.description.abstractNovel discrete complexes and coordination polymers of silver(I) and the water soluble 1,3,5-triaza-7-phosphaadamantane (PTA) or N-methyl-1,3,5-triaza-7-phosphaadamantane (PTAMe) have been isolated from the reactions of various silver(I) salts (AgX; X = CNˉ, CO₃²ˉ, NO₃ˉ, O₂CCH₃ˉ, O₂CCF₃ˉ, ClO₄ˉ, O₃SCF₃ˉ, O₃SCCH₃ˉ, BF₄ˉ) with PTA or PTAMe giving a total of 15 compounds. The Ag-PTA coordination compounds are named DCC₁₋₃ for discrete complexes, CP₁₋₅ for one dimensional coordination polymers and CN₁₋₅ for two dimensional coordination networks while the Ag-PTAMe coordination compounds are named m-CP₁₋₄ for one dimensional coordination polymers. The synthesized silver(I) coordination compounds were analysed using Nuclear Magnetic Resonance (NMR) spectroscopy, infrared spectroscopy (IR), Electron Spray Ionization Mass Spectrometry (ESI-MS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Coordination of PTA and PTAMe via the phosphorus and nitrogen atoms of the PTA moieties was confirmed by ¹H-, and ³¹P-NMR. IR spectroscopic studies confirmed the presence of ligands and the silver(I) salt counter ions used whilst the ESI-MS results showed m/z peaks that are attributed to the products, fragmentation of the polymeric species and the formation of multiple charged ionic species. Thermal stability studies (TGA and DSC) revealed that the silver(I)-PTA coordination compounds were thermally stable up to approximately 210 °C. [Ag(PTA)(μ²-O₂CCH₃)]n.2H₂O (CP₂) and [Ag(PTA)(μ¹-O₂CCF₃)]n (CP₃) formed double stranded, ladder-like structures in which the carboxylate anions bridge Ag(I) centres in a μ²-O₂ and μ¹-O₂ fashions resulting in short and long Ag…Ag separation, respectively. [Ag₂(μ²-O₂CCF₃)₂(μ¹-O₂CCF₃)(PTAMe)]n (m-CP₃) has a 1D single stranded coil-like structure which contains PTAMe groups coordinating via the phosphorus atom only. The polymer propagates via the trifluoroacetate groups which bridge the Ag(I) centres in an alternating μ₂-O₂ and μ₁-O₂ bridging modes. The two bridging modes of the trifluoroacetate groups also resulted in the formation of alternating segments displaying Ag…Ag interactions and non-Ag…Ag interactions along the coil-like polymer. 2D coordination networks [Ag(PTA)(H₂O)]n(NO₃)n (CN₁) and [Ag₂(PTA)₂(H₂O)]n(O₃SCF₃)₂n (CN₂) have stacked 2D corrugated sheet-like structures with channels filled with uncoordinated anions between the stacked sheets. The 2D networks contained PTA groups that displayed an alternating P-,N-,N’- coordination mode which is responsible for the growth of the polymer. O-H…O, O-H…N, C-H…O, C-H…N and C-H…F types of hydrogen bonding were observed in most crystal structures. This work also included the preparation of a silver(I)-PTA coordination compound containing ancillary ligands such as 4-nitrophenol from the solvothermal reaction of AgNO₃, PTA and 4-nitrophenol (4-NP). In an attempt to grow crystals for structural determination, a discrete, tri-coordinated silver-PTA complex [Ag(PTA)₃][4-NP]̣₁₀ (DCC₃) crystallized in a monoclinic system that co-crystallized along with ten molecules of 4-nitrophenol and a two-dimensional silver(I)-PTA sheet-like polymer [Ag₂(PTA)₂(μ₁-NO₃)(H₂O)](NO₃)(4-NP)(H₂O) (CN₅) co-crystallized with the 4-NP molecules positioned in between the sheets were obtained.en
dc.description.notesTitle page is missing from the digital copy.en
dc.subjectOrganometallic compounds.en
dc.subjectSilver compounds.en
dc.subjectChemistry, Inorganic.en
dc.titleSynthesis, spectroscopic and structural elucidation of discrete, one dimensional and two dimensional coordination compounds of 1,3,5-triaza-7-phosphaadamantane, N-methyl-1,3,5-triaza-7-phosphaadamantane and silver(I).en


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