Date of Award
Open Access Dissertation
Chemistry and Biochemistry
Richard D. Adams
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)9[η 1 -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.
Kaushal, M.(2022). Small Molecule Activation by Dirhenium Carbonyl Complexes. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/6962