Date of Award

9-12-2008

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biology

First Advisor

Stahl, Lothar

Abstract

Cyclodiphosph(V)azane ligands of the general formula [R(H)NE=P(μ-N tBu)2P=EN(H)R] where R = tBu, Ph, or Cy, and E = O, S, Se, or N-p-tolyl were synthesized and structurally characterized. Reaction of PCl3 and H2NtBu produced [ClP(μ-NtBu)2PCl]. Treatment of [ClP(μ-N tBu)2PCl] with LiN(H)R produced [R(H)NP(μ-Nt Bu)2PN(H)R] which was then oxidized using elemental sulfur and selenium, para-tolyl azide, and cumene hydroperoxide, generating ligands of general formula [R(H)NE=P(μ-NtBu) 2P=EN(H)R]. Treatment of [R(H)NE=P(μ-NtBu)2P=EN(H)R] with metal alkyls or amides produced complexes of the type {LnM[RNE=P(μ-N tBu)2P=ENR]MLn} and {LnM[RNE=P(μN tBu)2P=EN(H)R]} where M = Al, Zn, Zr, or Ti, and L = alkyl, amido, or THF ligands. Diphosphine ligands of general formula {[Me2Si(NR′)(NR ″)P](μ-NR)[P(NR′)(NR″)SiMe 2]} where R, R′, and R″ = tBu, iPr, Ph, or 2,6-diisopropylbenzene, were synthesized through SN2 reactions between [Me2Si(NR′ )(NR″)PCl] and LiHNR. These ligands were then treated with NiBr2[(CH3OCH2CH2) 2O], Rh(COD)2BF4, PdCl2(PEt3) 2, and Mo(CO)4(Pip)2 to generate their phosphine-chelated metal complexes. All novel molecules reported were characterized using standard NMR, IR, melting point, and elemental analysis techniques. Further structural details were determined using single-crystal X-ray diffraction methods where applicable. Catalytic activities toward polymerization of ethylene, and hydrogenation of unsaturated alkenes were determined for select metal complexes. It was found that {[Me2Si(μ-NtBu)2 P](μ-CH2CH2)[P(μ-NtBu) 2SiMe2]Rh(COD)}BF4 (44) is an active catalyst for the hydrogenation of 1-octene. Compounds {[tBu(H)NS=P(μ-N tBu)2P=N(p-tol)NtBu]TiCl 3}(25), {[tBuN(H)S=P(μ-NtBu) 2P=SNtBu]ZrCl2(NEt2)} (29 ), {[Me2Si(μ-NtBu)2P](μ-N iPr)[P(μ-NtBu)2SiMe2]}NiBr 2 (46), and {[Me2Si(μ-NtBu) 2P](μ-NPh)[P(μ-NtBu)2SiMe 2]}NiBr2 (47) were found to be active catalyst for the polymerization of ethylene upon treatment with methaluminoxane.

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