Mixed-metal clusters have been obtained from the reaction of titanium alkoxides with either strontium or lead acetate and methacrylic acid.

Recently we published the synthesis of new hybrid materials, ionic silica nanoparticles networks (ISNN), made of silica nanoparticles covalently connected by organic bridging ligands containing imidazolium units owing to a “click-chemistry-like” reaction. Among other techniques small-angle X-ray scattering (SAXS) experiments were carried out to get a better picture of the network extension. It turned out that the short-range order in ISNN materials was strongly influenced by the rigidity of the bridging ligand, while the position of the short-range order peaks confirmed the successful linking of the bridging ligands. The photoluminescence experiments reported in this communication revealed strongly enhanced emission in the hybrid material in comparison with neat imidazolium salts. Moreover the shift of the emission maximum toward longer wavelengths, obtained when varying the aromatic ring content of the bridging ligand, suggested the existence of strong π−π stacking in the hybrid material. Experiments revealed a stronger luminescence in those samples exhibiting the higher extent of short-range order in SAXS.

New phosphonate/acetate-substituted titanium oxo/alkoxo clusters were prepared from Ti(OiPr)4 and bis(trimethylsilyl) phosphonates in the presence of acetic acid, which served to generate water in situ through ester formation. The process led to clusters with a higher degree of condensation than in previously known phosphonate-substituted titanium oxo clusters. The clusters [Ti6O4(OiPr)10(OAc)2(O3PR)2] (OAc = acetate) were obtained for a large variety of functional and non-functional groups R under a range of reaction conditions. This cluster type, which is also retained in solution, therefore appears to be very robust. Two other clusters, [Ti5O(OiPr)11(OAc)(O3PCH2CH2CH2Br)3] and [Ti5O3(OiPr)6(OAc)4(O3P-xylyl)2], were only isolated in special cases.

The reaction of titanium isopropoxide, Ti(OiPr)4, with bis(trimethylsilyl) phosphonates has led to structures containingTi3O units [= Ti3(μ3‐O)(μ2‐OiPr)3(OiPr)3(O3PR)3] as the basic structural motif. This unit can be capped by a single Ti(OiPr)2L group (L = neutral ligand) through phosphonate bridges (for R = xylyl), or sandwich‐like structures can be formed with two Ti3O units bonded to a central Ti atom (for R = CH2CH2CH2Cl or benzyl). For R = allyl or ethyl, dimeric clusters were formed in which two Ti4 cluster units are bridged by isopropyl phosphonate ligands. For comparison, Ti(OiPr)4 was also treated with allylphosphonic acid to yield a Ti4 cluster. The reaction of Ti(OiPr)4 with the bulky bis(trimethylsilyl) 2‐naphthylmethyphosphonate did not yield an oxo cluster but instead the phosphonate‐substituted titanium alkoxide Ti4(OiPr)8(O3PCH2naphthyl)4.