2013-05-23 08:05:28 1228 Lilit Aboshyan-Sorgho, Céline Besnard, Phil Pattison, Kevin R. Kittilstved, Annina Aebischer, Jean-Claude G. Bünzli, Andreas Hauser, Claude Piguet Aboshyan-Sorgho, Lilit Besnard, Céline Pattison, Phil Kittilstved, Kevin R. Aebischer, Annina Bünzli, Jean-Claude G. Hauser, Andreas Piguet, Claude Angewandte Chemie International Edition Angew. Chem. Intl. Ed. 1433-7851 2011 50 4108 4112 H helical structures;lanthanides;photochemistry;self-assembly;upconversion helical structures lanthanides photochemistry self-assembly upconversion http://onlinelibrary.wiley.com/doi/10.1002/anie.201100095/abstract;jsessionid=C352764B1E9229A45C8C5FB9AEA7917B.d02t01 http://onlinelibrary.wiley.com/doi/10.1002/anie.201100095/pdf The connection of two Cr^III sensitizers around a central Er^III acceptor in a self-assembled cation provides high local metal concentrations that favor efficient nonlinear energy transfer upconversion luminescence (see picture). Upon selective low-energy near-infrared irradiation of Cr^III-centered transitions, 1 displays an unprecedented molecular two-photon upconverted green Er^III-centered emission.

]]> H210I421P653V 10.1002/anie.201100095 15714 http://www.unige.ch/sciences/chifi/publis/pics/double/ref01228.png http://www.unige.ch/sciences/chifi/publis/refs_pdf/ref01228.pdf 634 Stéphane Torelli, Daniel Imbert, Martine Cantuel, Gérald Bernardinelli, Sandra Delahaye, Andreas Hauser, Jean-Claude G. Bünzli, Claude Piguet Torelli, Stéphane Imbert, Daniel Cantuel, Martine Bernardinelli, Gérald Delahaye, Sandra Hauser, Andreas Bünzli, Jean-Claude G. Piguet, Claude Chemistry - A European Journal Chem. - Eur. J. 0947-6539 2005 11 11 3228 3242 H energy transfer; helicates; heterobimetallic complexes; lanthanides; near infrared luminescence energy transfer helicates heterobimetallic complexes lanthanides near infrared luminescence http://www3.interscience.wiley.com/cgi-bin/abstract/110431523/ABSTRACT http://www3.interscience.wiley.com/cgi-bin/fulltext/110431523/HTMLSTART http://www3.interscience.wiley.com/cgi-bin/fulltext/110431523/PDFSTART Inert and optically active pseudo-octahedral Cr^IIIN₆ and Ru^IIN₆ chromophores have been incorporated by self-assembly into heterobimetallic triple-stranded helicates HHH-[CrLnL₃]⁶⁺ and HHH-[RuLnL₃]⁵⁺. The crystal structures of [CrLnL₃](CF₃SO₃)₆ (Ln=Nd, Eu, Yb, Lu) and [RuLnL₃](CF₃SO₃)₅ (Ln=Eu, Lu) demonstrate that the helical structure can accommodate metal ions of different sizes, without sizeable change in the intermetallic M^…Ln distances. These systems are ideally suited for unravelling the molecular factors affecting the intermetallic nd→4f communication. Visible irradiation of the Cr^IIIN₆ and Ru^IIN₆ chromophores in HHH-[MLnL₃]^5/6+ (Ln=Nd, Yb, Er; M=Cr, Ru) eventually produces lanthanide-based near infrared (NIR) emission, after directional energy migration within the complexes. Depending on the kinetic regime associated with each specific d-f pair, the NIR luminescence decay times can be tuned from micro- to milliseconds. The origin of this effect, together with its rational control for programming optical functions in discrete heterobimetallic entities, are discussed.

]]> P530 10.1002/chem.200401158 3273 http://www.unige.ch/sciences/chifi/publis/refs_pdf/ref00634.pdf