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Two hybrid materials (1_TiO 2 and 2_TiO 2) were designed and prepared by anchoring novel [Cp*Ir(k 3-O,N,O-glyphosate)] (1; glyphosate = N-(phosphonomethyl)glycine) and [Cp*Ir(k 3-O,N,Oglyphosine)] (2; glyphosine = N,N-bis(phosphonomethyl)glycine) complexes onto rutile TiO 2. Characterization in solution (NMR spectroscopy) and solid state (X-Ray diffractometry) indicates that 1 and 2 are stabilized by the two arms of the glycine fragment, whereas they have (2) or can easily generate (1 and 2) a dandling phosphonate arm suitable for their anchoring on TiO 2. As a matter of fact, they exhibit rather elongated Ir-OP (1: 2.1405 Å, 2: 2.142 Å) and short Ir-OC (1: 2.0784 Å, 2: 2.086 Å) and Ir-N (1: 2.155 Å, 2: 2.207 Å) bonds. NMR spectra of 2 show a dynamic process that exchanges the two phosphonate moi-eties, consistently with an easy-OP detachment from Ir. Both molecular and heterogenized species were tested as catalysts in water oxidation (WO) driven by NaIO 4. 1 (TOF up to 96 min À 1) and 2 (26 min À 1) proved to be effective molecular catalysts; more importantly, 1_TiO 2 and 2_TiO 2 showed very high activity (TOF~200 min À 1), which remained rather constant over seven successive runs, even if substantial leaching of the noble metal in solution occurred during the first catalytic tests. TON was very high and limited only by the amount of NaIO 4 used. These results show the potentialities of mixed carboxylate/phosphonate ligands for the development of highly active water oxidation catalysts.

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Surface-modified ZnAl layered double hydroxides (LDHs) were prepared by reaction of AgNO3, with both ZnAlCl (LDH1) and ZnAlCO3 exchanged on the surface with chloride anions (LDH3). In this way, AgCl nanoparticles with crystalline domains ranging from 40 to 100 nm were grown on the LDH surface. An additional sample was prepared by partial reduction of silver to obtain Ag@AgCl-LDH (LDH2). The composites were tested as catalysts in Rhodamine B (RhB) degradation, wherein LDH2 showed complete cleavage of RhB after 45 min of irradiation versus 70 min needed in the presence of AgCl. This time decreased to 35 min for LDH1 and 15 min for LDH3, underlining the role of the AgCl dimensions and anion in the interlayer region. Studies on the reactive species involved in the degradation process revealed that, for all catalysts, O2·− was the main active species, while, to some extent, holes contribute to the activity of the LDH3. Finally, the composites showed high bactericidal activity, under irradiation, against Escherichia coli, comparable with that of Gentamicin, the positive control. A synergic effect of silver released from the composites and the production of reactive oxygen species was considered.

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