New tunable metal phosphine complexes with polymerisation capabilities Bo Cao 2134/26546 https://repository.lboro.ac.uk/articles/thesis/New_tunable_metal_phosphine_complexes_with_polymerisation_capabilities/9395882 <p>A new series of alkene based functionalised phosphorus ligands bearing PCN backbones were synthesised using a phosphorus Mannich condensation reaction. They were further studied by coordination to various transition metal centres. Following a procedure well established within our research group, two phosphorus ligands were obtained using [P(CH<sub>2</sub>OH)<sub>4</sub>]Cl (THPC). THPC was reacted with <em>ortho</em> and <em>para</em> anilines to give the phosphonium salts [P{CH<sub>2</sub>N(H)R}<sub>4</sub>]Cl [R = o–{C(Me)=CH<sub>2</sub>}C<sub>6</sub>H<sub>4</sub>, p–(CH=CH<sub>2</sub>)C<sub>6</sub>H<sub>4</sub>]. They were reacted with <sup>t</sup>BuOK to produce P{CH<sub>2</sub>N(H)R}<sub>3</sub> phosphines [R = o–{C(Me)=CH<sub>2</sub>}C<sub>6</sub>H<sub>4</sub>, p–(CH=CH<sub>2</sub>)C<sub>6</sub>H<sub>4</sub>]. In addition, new phosphine ligands were synthesised by reacting alkene containing amines (2–isopropenylaniline, 4–vinylaniline, 2–aminoethyl methacrylate hydrochloride) with one or two equivalents of hydroxymethyldiphenylphosphine, Ph<sub>2</sub>PCH<sub>2</sub>OH. These ligands were coordinated with a number of transition metals [Pd(II), Pt(II), Rh(III), Rh(I), Ru(II), Au(I)]. Coordination chemistry of P{CH<sub>2</sub>N(H)R}<sub>3</sub> (R = p–{CH=CH<sub>2</sub>}C<sub>6</sub>H<sub>4</sub>) was unsuccessful as the product changes colour and becomes insoluble in both sunlight and under a dark environment.</p> <p>The family of alkyne based functionalised phosphorus ligands was extended by reacting alkyne containing amines (1–ethynylcyclohexylamine, 2–ethynylaniline, 3–ethynylaniline, 4–ethynylaniline) with Ph<sub>2</sub>PCH<sub>2</sub>OH. 1–Ethynylcyclohexylamine and 2–ethynylaniline were able to react with only one equivalent of Ph<sub>2</sub>PCH<sub>2</sub>OH while 3–ethynylaniline and 4–ethynylaniline reacted with two equivalents of Ph<sub>2</sub>PCH<sub>2</sub>OH. 2–ethynylaniline and 4–ethynylaniline were synthesised following literature procedures however they were purified using different procedures. These ligands were treated with transition metals [Pd(II), Pt(II), Rh(III), Rh(I), Ru(II)] to study their coordination properties. In all cases, the ligands bond through the P–donor ligands. </p> <p>Another five potentially polymerisable phosphorus ligands were synthesised to enlarge the family of polymerisable monomers. They were synthesised from various amines [dopamine, 3–amino–2–azepanone, 4–(4,4,5,5–tetramethyl–1,3,2–dioxaborolan–2–yl)phenylamine, 4–(2–aminoethyl)morpholine] and appropriate amounts of Ph<sub>2</sub>PCH<sub>2</sub>OH. 3–Amino–2–azepanone was synthesised following the literature procedure by reacting L–lysine methyl ester dihydrochloride with NaOH. The study of 4–(4,4,5,5–tetramethyl–1,3,2–dioxaborolan–2–yl)phenylamine and 4–(2–aminoethyl)morpholine) reacting with Ph<sub>2</sub>PCH<sub>2</sub>OH has been successful while their coordination chemistries were only studied briefly. These phosphine ligands were subsequently reacted with transition metals [Pd(II), Pt(II), Rh(III), Rh(I), Ru(II)]. All these phosphine ligands and their coordinated monomers were characterised by <sup>31</sup>P{<sup>1</sup>H} NMR, IR spectroscopy and MS. Two of the compounds were further confirmed by single crystal X–ray crystallography.</p> <p>A preliminary study of polymerisation work was conducted on four of the alkene based metal supported monomers [PdCl<sub>2</sub>L, L = Ph<sub>2</sub>PCH<sub>2</sub>N(R)CH<sub>2</sub>PPh<sub>2</sub>, R = 4–vinylaniline; RhCl<sub>2</sub>(Cp*)L, L = Ph<sub>2</sub>PCH<sub>2</sub>NH(R), R = o–{C(Me)=CH<sub>2</sub>}C<sub>6</sub>H<sub>4</sub>, [RhCl<sub>2</sub>(Cp*)]<sub>2</sub>L, L = Ph<sub>2</sub>PCH<sub>2</sub>N(R)CH<sub>2</sub>PPh<sub>2</sub>, R = p–(CH=CH<sub>2</sub>)C<sub>6</sub>H<sub>4</sub>, RhCl(cod)L, L= Ph<sub>2</sub>PCH<sub>2</sub>NH(R), R = o–{C(Me)=CH<sub>2</sub>}C<sub>6</sub>H<sub>4</sub>]. The products were insoluble in regular solvents such as MeOH, EtOH, and NMR solvents CDCl<sub>3</sub>, (CD<sub>3</sub>)<sub>2</sub>SO, D<sub>2</sub>O which is very much different from the literature and were characterised using IR spectroscopy, MS and elemental analysis. The disappearance of the C=C double bond indicated a possible reason for successfully preliminary study of polymerisation. </p> 2022-08-03 10:02:14 Chemistry Chemical Sciences not elsewhere classified