Date of Award

Summer 2022

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

First Advisor

Richard D. Adams

Abstract

The background of small molecule activation is discussed in Chapter 1. Carbon-hydrogen (C-H) bond activation and carbon-carbon (C-C) bond formation using transition metal complexes are explained using examples from the literature. It also includes the previous work done by Dr. Adams’ lab on C-H bond activation and zwitterions in metal carbonyl complexes.

The reaction of Re2(CO)8(µ-C6H5)(µ-H) with vinyl acetate yielding three new products has been discussed in Chapter 2. One of the products Re3(CO)13(µ-η2 -C2H3), 2.3 further reacts with I2 resulting in the cleavage of Re(CO)5 group to yield the known compound Re(CO)5I and the new dirhenium complex Re2(CO)8I(µ-η2 -C2H3), 2.6 containing a µ-η2 -(σ+π) coordinated vinyl group.

The reaction of Re2(CO)10 with acetylene and Me3NO, yielding dirhenium complex Re2(CO)9(NMe3), 3.6 and the new zwitterionic complex Re2(CO)91 -Ε-2- CH=CH(NMe3)], 3.7 has been presented in chapter 3. Reactions of 3.7 with PMePh2 and PPh3 has yielded the zwitterionic 2-arylphosphonioethenyl-coordinated dirhenium carbonyl complexes, Re2(CO)9[η 1 -E-2-CH=CH(PPh2Me)], 3.9a and Re2(CO)9[η 1 -E-2- CH=CH(PPh3)], 3.9b and the zwitterionic 1-phosphonioethenyl ligand in the dirhenium carbonyl complexes, Re2(CO)9[η 1 -1-C(PPh2Me)(=CH2)], 3.10a, Re2(CO)8[µ- η 2 -1- C(PPh2Me)(=CH2)], 3.11a and Re2(CO)8[[µ- η 2 -1-C(PPh3)(CH2)], 3.11b, respectively. Compound 3.10a was converted to 3.11a and the new compound Re2(CO)7(µ-H)[ µ-η2 -1- (CH2C)P(Ph)(Me)(o-C6H4)], 3.12 by decarbonylations using Me3NO.

Chapter 4 explains the reactions of the zwitterionic dirhenium complex Re2(CO)8[µ- η 2 -1-C(CH2)(PMePh2)], 4.3 with the terminal alkynes, HC≡COEt and HC≡CPh. They yielded two new isomeric ethoxy-substituted dirhenium complexes, Re2(CO)7[µ- η 3 -C(H)C(OCH2CH3)CH2C(PMePh2)], 4.5 and Re2(CO)7[µ- η 3 - C(OCH2CH3)C(H)CH2C(PMePh2)], 4.6 and one phenyl-substituted dirhenium complex Re2(CO)7[µ- η 3 -C(H)CPhCH2C(PMePh2)], 4.7, respectively, with each containing a bridging, substituted 1-phosphonio-3,4-butenyl ligand formed by loss of CO and the addition and coupling of one alkyne to the CH2 group of the 1-phosphonioethenyl ligand in 4.3. On heating, compound 4.5 was converted to two new compounds: Re2(CO)6(µ-H)[ µ- η 4 -C(H)C(OCH2CH3)CHC(PMePh2)], 4.8, by loss of a CO ligand and a CH activation at the CH2 group in its C(H)C(OCH2CH3)CH2C(+PMePh2) ligand and an isomer Re2(CO)6(PMePh2)[ µ- η 4 -C(H)C(OCH2CH3)CHCH], 4.9.

Included in

Chemistry Commons

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