Photoinduced Energy Transfer between Ruthenium and Osmium tris-Bipyridine Complexes Covalently Pillared into γ-ZrP

Abstract

This paper describes the preparation and photophysical characterization of hybrid materials made of a γ-ZrP covalently pillared with two complexes: Ru(bpy)2L and Os(bpy)2L (bpy ) 2,2′-bipyridine and L ) 5,5′-bis(dihydroxyphosphoryl)-2,2′-bipyridine). A high degree of phosphate (H2PO4) exchange by the complexes in the γ-ZrP matrix was achieved (25% intercalation) by preintercalating the γ-ZrP with octylamine. Materials with different Os/Ru ratios were prepared, allowing the study of the efficiency of energy transfer as a function of the Ru/Os ratio (Ru/Os ratios ) 1/0, 1/0.35, 1/0.6, 1/0.8, 1/1, and 0/1). Powder X-ray diffraction shows that the interlayer space of the intercalated γ-ZrP is approximately 18.6 Å in all of the intercalated materials. Solid-state 31 P NMR confirms that the complexes are covalently bonded to the zirconium of the γ-ZrP phase. All of the materials exhibit moderately strong metal-to-ligand charge transfer (MLCT) emission from the Ru and/or Os chromophores. In the mixed samples the Ru-based emission is strongly quenched, indicating that in the γ-ZrP matrix rapid Ru to Os energy transfer occurs. On the basis of the lifetimes of the Ru MLCT luminescence, the energy transfer rate is estimated to be 2-3 × 10 8 s -1 for chromophores that are adjacent in the γ-ZrP matrix.

Sulfonated nanoplates in proton conducting membranes for fuel cells

“…S2a). 35 XPS analysis in the Si 2p region of the s-ZrP nanoplates (Fig. S2b), which shows a peak at 104 eV attributed to Si-O bonding, also confirms the presence of siloxane on s-ZrP nanoplates.…”

Förster Energy Transport in Metal–Organic Frameworks Is Beyond Step-by-Step Hopping

“…Natural photosynthesis begins by efficiently funneling energy collected from sunlight to reaction centers via exciton transport. , To study this process, exciton migrations over long distances have been explored in artificial networks − such as light-harvesting metal–organic frameworks (MOFs). − As a structurally well-defined platform, − MOFs not only present new opportunities for the judicious design of antenna materials using chromophore-based ligands, − but also enable study of energy transport dynamics in networks with well-defined structures. − The chromophores can be isolated from each other on the MOF skeleton with interchromophore distances of usually 1–2 nm, a value very close to that in natural photosynthetic membranes (e.g., interchlorophyll distances are 1–1.3 nm in chloroplasts). − This ligand separation in space leads to energy transfer in a weak electronic coupling regime, in contrast to molecular crystals with direct close packing and strong electronic coupling. MOF crystals are thus extremely favorable crystalline models for photosynthetic antenna arrays in green plants and photosynthetic bacteria. , …”

Steric Coordination Control of Interchain Interactions in Conducting Metallopolymers

“…Air sensitive operations were carried out in an MBraun dry box or using standard Schlenk line techniques under N 2 . The materials M1, [58] P1, [42] 5,5 0 -bis(diethylphosphonylmethyl)-2,2 0 -bipyridine [59] and (E),(E)-1,4-bis(4-formyl-3,5-dimesitylstyryl)-2,5-di-n-hexyloxybenzene [60] were prepared by literature procedures. NMR spectra were obtained using a Bruker Avance 300 spectrometer operating at 300 MHz for protons.…”