Date of Award

2007

Publication Type

Doctoral Thesis

Degree Name

Ph.D.

Department

Chemistry and Biochemistry

Keywords

Pure sciences, Heterometallic, Ligands, Polynuclear

Supervisor

Samuel A. Johnson

Rights

info:eu-repo/semantics/openAccess

Abstract

The tripodal amido ligands P(CH2NHArR) 3 can be utilized to produce mononuclear Ti, Zr, and Ta complexes, where ArR = 3,5-(CF3)2C6H3 , Ph, and 3,5-Me2C6H3. The mononuclear compound P(CH2N-3,5-Me2C6H3) 3TiNMe2 reacts with excess Ni(CO)4 to afford an early-late heterobimetallic complex (CO)3Ni[P(CH2N-3,5-Me 2C6H3)3]TiNMe2 or a trinuclear complex (CO)2Ni[P(CH2N-3,5-Me2C6H 3)3TiNMe2]2. The reactions of 4 equiv of the mononuclear early transition metal complexes P(CH2NArR) 3TiNMe2 or P(CH2NArR)3Ta=N tBu with [Rh(CO)2(μ-Cl)]2 produce the trinuclear trans-rhodiumcarbonylchlorobisphosphine complexes. The donor abilities of the phosphine complexes are affected by the direct interactions between the phosphine donors and Ti or Ta metal centers.

The reaction of phosphine ligand P(CH2NHPh)3 with nickelocene Cp2Ni produces a Ni(II) dimer [CpNiP(CH2NHPh) 2]2 with a bridging diamido-phosphido ligand. Ni[P(CH 2NHPh)3]4 is identified as an intermediate. The Ni(II) dimer can be used as a ligand to give the early-late transition tetranuclear heterometallic complex [CpNiP(CH2NPh)2Ti(NMe2) 2]2.

The reactions of P[CH2NArR]3ZrCl(THF) with cyclopentadienyl lithium (LiC5H5) or lithium salt of the fulvalene dianion (Li2C10H8) produce P(CH2NArR)3ZrCp and the bridged binuclear complexes trans-[P(CH2NArR) 3Zr]2(η5:η5-C 10H8), respectively, where ArR = Ph and[special characters omitted] 3,5-Me2C6H3. The mononuclear titanium complexes [P(CH2NArR)3]TiOC6H 4tBu and the binuclear species [P(CH 2NPh)3Ti]2-μ-4,4′{O[3,3 ′,5,5′-(C6H2Me 2)2]O}, {[P(CH2NPh)3]Ti}2(μ-O), and [P(CH2N-3,5-Me2C6H3 )3]Ti-μ-O-Ti(NMe2)3, are prepared from [P(CH2NArR)3]TiNMe2 via protonolysis. One equiv of {[P(CH2NPh)3]Ti}2(μ-O) precipitates a polymer of {Cl(CO)Rh[P(CH2NPh)3Ti] 2O}n. A single CO stretch is observed in the IR spectrum of a KBr pellet at 1972.5 cm−1.

Se=P(CH2NHArR)3 are prepared by oxidation of [P(CH2NHArR)3], which can react with AlMe3 to afford [P(CH2NArR) 2Se](AlMe2)3 or Me3AlP(CH2NAr R)2Se(AlMe2)3 with the unanticipated diamidoselenophosphinito ligands, where ArR = 3,5-(CF 3)2C6H3, Ph, and 3,5-Me2C 6H3. Comparing the reactions with P(CH2NHAr R)3, only P(CH2NArR)3Al 2Me3 or Me3Al·P(CH2NAr R)3Al2Me3 are produced without P-C bond cleavage.

Se=P[CH2NH-3,5-(CF3)2C6H 3]3 reacts with n-butylmagnesium to produce a binuclear magnesium complex bridging with a bisphosphine ligand {P 2[CH2N-3,5-(CF3)2C6H 3]4}(MgTHF2)2 by the cleavage of the P-C bond and the Se=P bond, with concomitant loss of [nBuCH 2N-3,5-(CF3)2C6H3] 2Mg. Byproducts include elemental selenium and SeMg. Se=P(CH2NHAr R)3 are efficiently reduced by Zr(NEt2) 4 to produce the mononuclear zirconium complexes [P(CH2NAr R)2SeZrNArRCH2NEt2], where ArR = Ph and 3,5-Me2C6H3.

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