The Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. , A. and Reglinski, J. (2010) A simple, novel method for preparing an effective water oxidation catalyst. Mills

The sequential syntheses, structural characterisation and reactivity studies of a series of discrete early-late mixed-metal complexes supported by the unique amidophosphine ligand m-(But2CH)N(C6H4)PPh2L1 are described. This ligand was synthesised using a Schiff-base/ButLi protocol and the resultant lithium salt LiL1 found to adopt a tetrameric structure in the solid state in which both two-coordinate N-Li-N and eta6:eta6-arylLi metallocene bonding motifs are present. Reaction between HL1 and labile Pt(II) and Pd(II) chlorides formed MCl2(HL1)2 complexes 4 (M = Pt) and 5 (M = Pd) in which a weak N-H...pi(aryl) hydrogen bonding interaction was identified in the solid-state structure of 4. These compounds were found to be inert to transamination and protonolysis reactions with Ti amides and alkyls; instead, stepwise alkyl transfer from Ti to Pt, resulting in Pt(CH2SiMe3)2(HL1)2 6 was observed. Access to mixed-metal complexes was achieved using an early-metal-first approach. Reaction between the metalloligand TiCl2(L1)2 and labile Group 10 and group 9 compounds resulted in the formation of TiCl2(mu-L1)2PtCl2 8, TiCl2(mu-L1)2PtMe2 9, TiCl2(mu-L1)2PdCl2 10, TiCl2(mu-L1)2NiBr2 11, and [TiCl2(mu-L1)2RhCl(CO)]2 12. In the solid state, the Group 4/10 compounds 8, 9 and 10 adopt similar structures that exhibit both intramolecular But2C-H...Cl-Ti hydrogen bonding and arylNP pi-stacking interactions; this hydrogen-bonding interaction is conserved in solution. Unlike the above Group 4/10 complexes, the Ti-Rh complex 12 adopts a tetranuclear structure in the solid state that is stabilised by similar hydrogen-bonding and pi-stacking interactions. The Group 4/10 complexes were assessed as catalysts for olefin polymerisation and cross-coupling reactions. In combination with MAO, the mixed-metal complexes 8 and 10 were poor ethylene polymerisation catalysts and resulted in polymers of both high molecular weight and polydispersity. The Ti-Ni complex 11 formed oligomeric material only, while the mononuclear Ti metalloligand TiCl2(L1)2 gave the best results, showing low activity (6.14 kg mol(-1) bar(-1) h(-1)) and moderate polydispersity (12). The Ti-Pd complex 10 was assessed in arylamination and Suzuki-Miyaura reactions. While little or no catalytic activity was observed in arylamination reactions, 10 was found to effect Suzuki coupling between activated aryl bromides and phenylboronic acid at 80 degrees C. Unlike with TiCl2(L1)2, reactions between 8 and the reducing agents C8K or Mg led to intractable mixtures. However, the cyclic voltammetry of both compounds indicated that a reversible one-electron reduction process occurs at a similar potential (ca. -0.7 V) and was assigned to the formation of the monohalides TiCl(L1)2 and TiCl(mu-L1)2PtCl2. The reactivity of the metallocage TiCl(mu-L3)3Pt was also investigated. While reduction reactions were unsuccessful, the metallocage reacted with CO to form the Ti-Pt carbonyl, TiCl(mu-L3)3Pt(CO) 13. The X-ray crystal structure of 13 revealed that accommodation of CO at the Pt centre has cau...

The addition of a chloride ion to Pd and Rh complexes supported by the ureaphosphine ligand L results in the formation of chelating diphosphine complexes that retain some catalytic activity.

Supporting Information General experimental procedures Unless otherwise stated, all reactions were carried out in a Vacuum Atmospheres Omnilab glovebox or using standard Schlenk techniques under an atmosphere of oxygen free dinitrogen. Solvents were dried and degassed (hexane, toluene, diethyl ether and tetrahydrofuran were passed through activated alumina towers, 1 dichloromethane was dried over CaH 2 and distilled), and stored over 4 Å molecular sieves. d 6-benzene was boiled with K under vacuum and trap-to-trap distilled. The compounds TiCl 4 (THF) 2 , 2 m-H 2 NC 6 H 4 PPh 2 , 3 Li[L 1 ] and Li[L 2 ] 4 were prepared following literature procedures; all other reagents were used as purchased without further purification. The 1 H, 13 C{ 1 H}, 31 P{ 1 H} NMR spectra were recorded on a Bruker DPX-300 spectrometer operating at 300.36, 75.47, and 121.5 MHz respectively. 1 H and 13 C{ 1 H}NMR spectra were referenced internally while 31 P{ 1 H} NMR spectra were referenced externally to trimethylphosphite resonating at 142.0 ppm. EPR spectra were recorded at X-band frequency on a Bruker EMX EPR spectrometer. Cyclic voltametry was carried out under nitrogen using an Autolab PGSTAT potentiostat. A standard three-electrode setup was used, consisting of a Ag foil psuedo-reference electrode, a platinum wire auxiliary electrode and a platinum disk working electrode. The solute sample was 1.0 mM in freshly distilled CH 2 Cl 2 and 0.4 M in Bu n 4 N.BF 4 supporting electrolyte. The potentials were referenced by the addition of ferrocene (E 1/2 = 0.438 V). Solution magnetic moments were determined by Evan's method in C 6 D 6 /SiMe 4 with a C 6 D 6 /SiMe 4 insert. 5,6 Elemental analyses were carried out by Stephen Boyer at London Metropolitan University.

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