title: Cu(II)-selective bispidine-dye conjugates.
abstract: The substitution of tetradentate bispidine ligands with rhodamine and cyanine dye molecules, coupled to an amine donor, forming an amide as potential fifth donor, is described. Bispidines are known to lead to very stable Cu(II) complexes, and the coordination to Cu(II) was expected to efficiently quench the fluorescence of dye molecules. However, at physiological pH the amide is not coordinated, as shown by titration experiments and crystallographic structural data of three possible isomers of these complexes. This may be due to the specific cavity shape of bispidines and the Jahn-Teller lability of the Cu(II) center. While Cu(II) coordination in aqueous solution leads to efficient fluorescence quenching, experiments show that the complex stabilities are not large enough for Cu(II) sensing in biological media, and possibilities are discussed, how this may be achieved by optimized bispidine-dye conjugates.
authors.affiliation: Universität Heidelberg, Bioquant, Heidelberg, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Brox
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR), Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany. Electronic address: peter.comba@aci.uni-heidelberg.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Comba
authors.affiliation: Universität Heidelberg, Bioquant, Heidelberg, Germany. Electronic address: dirk.herten@bioquant.uni-heidelberg.de.
authors.forename: Dirk-Peter
authors.initials: DP
authors.lastname: Herten
authors.affiliation: Universität Heidelberg, Bioquant, Heidelberg, Germany.
authors.forename: Esther
authors.initials: E
authors.lastname: Kimmle
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR), Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Morgen
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR), Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Carmen L
authors.initials: CL
authors.lastname: Rühl
authors.affiliation: Universität Heidelberg, Bioquant, Heidelberg, Germany.
authors.forename: Arina
authors.initials: A
authors.lastname: Rybina
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, PF 510119, 01314 Dresden, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Stephan
authors.affiliation: Universität Heidelberg, Bioquant, Heidelberg, Germany.
authors.forename: Golo
authors.initials: G
authors.lastname: Storch
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR), Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Hubert
authors.initials: H
authors.lastname: Wadepohl
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D008024:Ligands; D008956:Models, Chemical; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D004396:Coloring Agents; D008024:Ligands; D009942:Organometallic Compounds; C495809:bispidine; D012972:Sodium Hydroxide; D003300:Copper
keywords: Amide coordination; Copper selectivity; Fluorescence quenching; Fluorescence sensor; Jahn–Teller distortion