Synthesis and reactivity of rare earth complexes involving formamidinates of moderate steric bulk

Salehisaki, Mehdi (2018) Synthesis and reactivity of rare earth complexes involving formamidinates of moderate steric bulk. PhD thesis, James Cook University.

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Abstract

This thesis explores the synthesis and characterisation of rare earth bis(aryl)formamidinate complexes of low to moderate steric bulk. Redox transmetallation/protolysis reactions were employed to synthesize the complexes. Reactivity of the compounds towards the Tishchenko reaction were studied using the standard reaction of benzaldehyde to form benzyl benzoate. Besides, some chemistry of Na, K, Zn and Al ‐ bis(aryl)formamidinate complexes is also discussed. Metalation reactions of the formamidine using metal alkyls produced a range of compounds. The following bis(aryl)formamidine ligands were used for each chapter:

N,N'‐(diphenyl)formamidine (PhFormH) Chapters: 2,4

N,N'‐bis(2,4‐dimethyl)formamidine (DMFormH) Chapters: 3,4

Chapter 2 describes a series of rare earth PhForm complexes which were prepared by redox transmetallation/protolysis (RTP) using the rare earth metals (Tb, Ho, Er, Y, Pr, Nd, Sm, Gd, Dy and Lu), bis(pentafluorophenyl)mercury (Hg(C₆F₅)₂), PhFormH and using THF as solvent. Trivalent complexes with the general formula [Ln(PhForm)₃(thf)ₓ].(THF)y were synthesized and characterized in this chapter. Investigation of reactivities towards the Tishchenko reaction revealed these compounds have promising catalytic properties and can be used for the Tishchenko reaction while [Y(PhForm)₃.(thf)₂].(THF)₃ has the highest reactivity compared with the other compounds in this chapter.

Chapter 3 investigates rare earth DMForm complexes prepared by RTP reactions using the rare earth metals (Y, Lu, Pr, Ho, Sm, Gd and Er), bis(pentafluorophenyl)mercury (Hg(C₆F₅)₂) and DMFormH. Different solvents (THF, DME or DMF) were used for the reactions. As results, trivalent complexes were synthesized with three chelating formaminate ligands about the metal centers. Study of reactivities towards the Tishchenko reaction shows the compounds in this chapter do indeed catalyse Tishchenko reaction. It was found that [Y(DMForm)₃(thf)] has the highest reactivity towards this reaction among all the compounds synthesized in this research.

Chapter 4 is a small contribution to the main group chemistry involving PhFormH and DMFormH ligands. This chapter presents the synthesis and structural characterisation of the new complexes [K(DMForm)(dme)]∞, [K₂(PhForm)N(SiMe₃)₂]∞, [Na(DMForm)(dme)₂], [Na(PhForm)(dme)]₂, [Zn₄(PhForm)₆O].THF and [Al(PhForm)₃]. These compounds can be used in future for metathesis and catalysis chemistry. This chapter shows decreasing steric effect of the ligand changes possible structures and bonding modes.

Overall this thesis contributes synthesis and reactivity of complexes involving formamidinates of moderate steric bulk to the fascinating field of metal‐formamidinate chemistry.

Item ID: 60374
Item Type: Thesis (PhD)
Keywords: lanthanoids; lanthanoid(II); lanthanoid(III); lanthanoid (IV); formamidinates
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Copyright Information: Copyright © 2018 Mehdi Salehisaki.
Additional Information:

The following publication has arisen from this thesis:

Deacon, Glen B., Hossain, Md Elius, Junk, Peter C., and Salehisaki, Mehdi (2017) Rare-earth N,N'-diaryformamidinate complexes. Coordination Chemistry Reviews, 340. pp. 247-265.

Date Deposited: 16 Sep 2019 05:46
FoR Codes: 03 CHEMICAL SCIENCES > 0302 Inorganic Chemistry > 030202 f-Block Chemistry @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970103 Expanding Knowledge in the Chemical Sciences @ 100%
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