Sol-gels and chemical sensors

Wolfbeis, Otto S.; Reisfeld, Renata; Oehme, Ines

doi:10.1007/bfb0111488

Cited by 58 publications

(33 citation statements)

References 119 publications

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“…The reversible uptake of small molecules (e.g. CO, CO 2 , SO 2 ) may be used as a means to “detect” them in the gas phase and can be applied in molecular sensors 3, 4, 28, 81, 82. Thus, for example, the Rh I phosphane–ether complex in Equation (9) was incorporated into thin films and shown by optical‐based sensing to selectively and reversibly coordinate CO in the presence of O 2 , CO 2 , N 2 , and H 2 under ambient conditions 3, 4…”

Section: Hemilabile Ligandsmentioning

confidence: 99%

Hemilability of Hybrid Ligands and the Coordination Chemistry of Oxazoline-Based Systems

Braunstein

Naud

2001

Angew. Chem. Int. Ed.

940

618

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Ligand design is becoming an increasingly important part of the synthetic activity in chemistry. This is of course because of the subtle control that ligands exert on the metal center to which they are coordinated. Ligands which contain significantly different chemical functionalities, such as hard and soft donors, are often called hybrid ligands and find increasing use in molecular chemistry. Although the interplay between electronic and steric properties has long been recognized as essential in determining the chemical or physical properties of a complex, predictions remain very difficult, not only because of the considerable diversity encountered within the Periodic Table—different metal centers will behave differently towards the same ligand and different ligands can completely modify the chemistry of a given metal—but also because of the small energy differences involved. New systems may—even through serendipity—allow the emergence of useful concepts that can gain general acceptance and help design molecular structures orientated towards a given property. The concept of ligand hemilability, which finds numerous illustrations with hybrid ligands, has gained increased acceptance and been found to be very useful in explaining the properties of metal complexes and in designing new systems for molecular activation, homogeneous catalysis, functional materials, or small‐molecule sensing. In the field of homogeneous enantioselective catalysis, in which steric and/or electronic control of a metal‐mediated process must occur in such a way that one stereoisomer is preferentially formed, ligands containing one or more chiral oxazoline units have been found to be very valuable for a wide range of metal‐catalyzed reactions. The incorporation of oxazoline moieties in multifunctional ligands of increasing complexity makes such ligands good candidates to display hemilabile properties, which until recently, had not been documented in oxazoline chemistry. Herein, we briefly recall the definition and scope of hemilabile ligands, present the main classes of ligands containing one or more oxazoline moieties, with an emphasis on hybrid ligands, and finally explain why the combination of these two facets of ligand design appears particularly promising.

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Section: Hemilabile Ligandsmentioning

confidence: 99%

Hemilability of Hybrid Ligands and the Coordination Chemistry of Oxazoline-Based Systems

Braunstein

Naud

2001

Angew. Chem. Int. Ed.

940

618

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“…Organosilica hybrids have, as an advantage, very low solubility in water and many polar and non-polar solvents, as well as high thermal stability. [7][8][9] During the past twenty years, optical studies performed on organic-inorganic nanocomposites have evolved towards different objectives: investigating the fundamental spectroscopy of lanthanide ions in the sol-gel environment, study of energy transfer between lanthanide ions and chelates (or dyes) in solid matrices, using luminescent molecules as probes for sol-gel processing, and finally developing materials with specific optical properties based on the properties of organic or inorganic chromophores. [10][11][12][13][14][15][16][17] But in the past years, research of these luminescent materials has also been focused on bioanalytical and bio-medical applications.…”

Section: Clément Sanchez Is Director Ofmentioning

confidence: 99%

Photonic and nanobiophotonic properties of luminescent lanthanide-doped hybrid organic–inorganic materials

et al. 2008

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Research into lanthanide-doped organic-inorganic hybrid materials emerged in the 1990s with the development of interesting materials for optics: high efficiency and stable solid-state lasers, new fiber amplifiers and sensors, devices with upconversion, fast photochromic and non-linear responses, etc. Their interest relies on the possibility of combining properties of sol-gel host materials (shaping, tunable refractive index and mechanical properties, corrosion protection, specific adhesion, etc.) and the well-known luminescence of lanthanide ions (Ln). The fast development of photonic hybrids allowed the commercial exploitation of products with new or enhanced characteristics (megajoule pulsed Nd-YAG laser, protective coatings of glasses, screens or glasswares). However, recently, Ln-hybrid nanocomposites have found new applications in bio-sensors, bio-analytics and even clinical imaging diagnostics. These applications make use of the fluorescence properties of lanthanides that make luminescent hybrids ideal candidates for time-resolved fluoroimmunoassays, DNA hybridation assays, fluorescence imaging microscopy, or in vivo imaging. As a consequence, the goal of this review is twofold: (i) as a reminder of some general considerations that must be taken into account to design new optically active Ln-doped nanocomposites whatever the application field, and (ii) to show the most important advances achieved in the past years in different areas, paying special attention to bio-medical applications.

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“…In these sensors, xerogels are applied into detection sites, change their optical properties due to the interaction with detected chemicals and these modifications are determined from changes of the output sensor signal. Different types of optical chemical sensors have already been investigated for this purpose, which employed different set ups based on bulk optics, integrated optics or fiber optics [1]. In comparison with the other types of optical sensors, the fiber-optic ones can be used for point, remote and distributed chemical sensors [2].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, xerogel materials have been widely investigated for employing in optical chemical sensors [1]. In these sensors, xerogels are applied into detection sites, change their optical properties due to the interaction with detected chemicals and these modifications are determined from changes of the output sensor signal.…”

Section: Introductionmentioning

confidence: 99%