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Synthesis, Characterization, and Reactivity of Titanocene Cyclic Organohydroborates; Synthesis, Spectroscopic Studies, and Structures of Lanthanide(II)-Cobalt Carbonyl Complexes

Plecnik, Christine Emily

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2003, Doctor of Philosophy, Ohio State University, Chemistry.

PART I: Low valent, paramagnetic titanocene (Ti(III)) cyclic organohydroborates Cp2Ti{(μ-H)2BR2} (R2 = C4H8, C5H10, C8H14) were synthesized, and their chemistry was explored. This family of complexes possess electron deficient Ti-H-B bridges that are reactive towards Lewis acids and bases. Bridging hydride ion is abstracted by the Lewis acidic reagent B(C6F5)3. Depending on the coordinating ability of the solvent, one of two distinct products is formed: Cp2Ti{(μ-H)2B(C6F5)2} from the noncoordinating solvent toluene and [Cp2Ti(L) 2] [HB(C6F5)3] (L = Et2O, THF) from the coordinating solvents Et2O and THF. The labile Et2O ligands of [Cp2Ti(OEt2)2] [HB(C6F5)3] are displaced in THF and toluene. The titanocene cyclic organohydroborates react with Lewis bases to cleave the double hydrogen bridge. Symmetrical bridge division is induced by PMe3, which provides Cp2TiH(PMe3). Ammonia primarily splits the bridge in an unsymmetrical fashion, which leads to [Cp2Ti(NH3)2] [H2B(C6F5)2]. The new chlorine-bridged titanocene cation [Cp2Ti(μ-Cl)2TiCp2]+ was also produced.

PART II: Novel lanthanide(II)-cobalt carbonyl complexes were prepared and structurally characterized (IR and 59Co NMR spectroscopies, single-crystal X-ray diffraction, laser desorption/ionization mass spectrometry). The transmetalation reaction between Ln and Hg[Co(CO)4]2 in coordinating solvent is a facile route toward two types of heterometallic compounds, solvent-separated ion pairs and isocarbonyls. Product formation is dictated by the relative nucleophilicities of the solvent and [Co(CO)4]-. Transmetalation in strong (Pyr) or moderately strong (THF, DME) coordinating solvents affords discrete ion pairs [Ln(L)x] [Co(CO)4]2. Isocarbonyls [(L)xYb{(μ-CO)yCo(CO)4-y}2·zTol] with 2-D sheetlike structures are produced by dissolving the salts [Yb(L)6] [Co(CO)4]2 in toluene. Transmetalation in the weak donating solvent Et2O generates 2-D isocarbonyl polymeric arrays, {(Et2O)3Ln[Co4(CO)11]}. The [Co4(CO)11]2- anion, undiscovered until now, results from oxidation/condensation of [Co(CO)4]-. Two isomers of [Co4(CO)11]2- (pseudo-C3v and C2v symmetries) were observed. The compound {(Et2O)3Yb[Co4(CO)11]} is unstable in Lewis basic solvents, and the cluster undergoes disproportionation.

Sheldon Shore (Advisor)
315 p.

Recommended Citations

Citations

  • Plecnik, C. E. (2003). Synthesis, Characterization, and Reactivity of Titanocene Cyclic Organohydroborates; Synthesis, Spectroscopic Studies, and Structures of Lanthanide(II)-Cobalt Carbonyl Complexes [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1047408488

    APA Style (7th edition)

  • Plecnik, Christine. Synthesis, Characterization, and Reactivity of Titanocene Cyclic Organohydroborates; Synthesis, Spectroscopic Studies, and Structures of Lanthanide(II)-Cobalt Carbonyl Complexes. 2003. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1047408488.

    MLA Style (8th edition)

  • Plecnik, Christine. "Synthesis, Characterization, and Reactivity of Titanocene Cyclic Organohydroborates; Synthesis, Spectroscopic Studies, and Structures of Lanthanide(II)-Cobalt Carbonyl Complexes." Doctoral dissertation, Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1047408488

    Chicago Manual of Style (17th edition)