It is our pleasure to welcome you to the 37th Annual Eastern Analytical Symposium and Exposition, and to the conference on "Photophysics and Application of Luminescent Metal Complexes" in particular. We have tried to put together an attractive program, with input both from academia and industry and from the United States as well as overseas. A detailed program and a survey of abstracts follows below.

We would like to acknowledge ASTM, E13.06, for stimulating us to organize the symposium. During the symposium we will supply further information on ASTM and hope to interest you to participate in future activities, such as the development of luminescence and other spectroscopic standards (including possible round robin tests), and in the development of new spectroscopic methods, practices and applications for rapidly evolving fluorescence instrumentation.

Last but not least, we would like to acknowledge the sponsors, SPEX Industries from Instruments SA, Photon Technology International, Inc., and Akzo Nobel, who have supported the conference, and of course all presenters for their contributions.

Hans Hofstraat DeLyle Eastwood

Philips Research Air Force Institute of Technology

Prof. Holstlaan 4 2950 P Street

NL-5656 AA Eindhoven Wright Patterson AFB

The Netherlands OH 45433 USA

tel. +31-40-2744910 tel. +1-513-255 3636 x 4537

fax +31-40-2743350 fax +1-513-255 2921

e-mail hofstraa@natlab.research.philips.com e-mail deastwoo@afit.af.mil

hanshof@worldonline.nl

and

University of Amsterdam

Institute of Molecular Chemistry

Nieuwe Achtergracht 129

NL-1018 WS Amsterdam

The Netherlands

Thursday, 09:00 AM - 12:15 PM

09:00 Introduction

Hans Hofstraat, Philips Research and University of Amsterdam

09:05 Advances in the Design and Applications of Sensors Based on Luminescent Transition Metal Complexes

JAMES N. DEMAS, Wenying Xu and Kristi Kneas

University of Virginia, Charlottesville, VA 22904, USA; jnd@faraday.clas.virginia.edu

A. DeGraff, James Madison University

09:25 Luminescence-Based Oxygen Sensors: Fluorescence Microscopy as a Probe of System Heterogeneity

KRISTI KNEAS, James N. Demas and Ammasi Periasamy

University of Virginia, Charlottesville, VA 22904, USA; jnd@faraday.clas.virginia.edu

A. DeGraff, James Madison University

09:45 Enhancement of the Photoluminescence and Electroluminescence Quantum Yield in Molecular Dispersed Solid Thin Films

HEDI MATTOUSSI, H. Murata, C.D. Merritt and Z.H. Kafafi

Naval Research Laboratory, Code 5611, Optical Sciences Division, Washington, DC 20375; hedimat@ccsalpha2.nrl.navy.mil

10:05 Photoluminescence of Uranium Compounds

DELYLE EASTWOOD and J. Martin

Dale L. Perry

Lawrence Berkeley National Laboratory, Berkeley, CA, USA

10:45 Break

11:05 Sensitizer-Functionalized Near-Infrared Emitting Lanthanide Complexes

STEVE I. KLINK, Frank J.C.M. van Veggel and David N. Reinhoudt

University of Twente, Department SMCT, P.O. Box 217, Enschede, The Netherlands

Johannes W. Hofstraat

Akzo Nobel Central Research, Arnhem, The Netherlands; present address: Philips Research, Eindhoven, The Netherlands

11:05 Tetraazatriphenylenes as Extremely Efficient Antenna Chromophores

FRANK J. STEEMERS

Tufts University

Esther G. Kerver, Willem Verboom and David N. Reinhoudt

University of Twente, Enschede, The Netherlands

Erik B. van der Tol, Jan W. Verhoeven and Hendrik J. van Ramesdonk

University of Amsterdam, The Netherlands

11:45 Terbium(III) as a Fluorescent Probe for the Elucidation of the Ion-Binding Properties and Degradation of Polyelectrolytes

HANNIA LUJAN-UPTON

Long Island University, University Plaza, Brooklyn, NY 11201, USA; hlujanup@hornet.liunet.edu

Yoshiyuki H. Okamoto and M.D. Cho

Polytechnic University, Brooklyn, NY, USA

 

Thursday, 14:00 - 15:15 PM

14:00 Surface Functionalized Up-Converting Phosphors for Immunoassays

Shang Li, Timothy L. Vail, Jarrett L. Burton, Keith Kardos and R.Sam Niedbala

STC Technologies, Inc., 1745 Eaton Ave., Bethlehem, PA 18018-1799, USA

14:20 Fluoresceindiaminotetracarboxylic Acid Derivatives as Efficient Sensitizers-Cum- Complexants for Near-IR Emitting Lanthanide Ions and Their Diagnostic Application

JOHANNES W. HOFSTRAAT, Martinus H.V. Werts and Jan W. Verhoeven

University of Amsterdam, Institute of Molecular Chemistry, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands and Philips Research, Eindhoven, The Netherlands;

hofstraa@natlab.philips.research.com/hanshof@worldonline.nl

Richard H. Woudenberg and Peter Emmerink

Akzo Nobel Central Research, Arnhem, The Netherlands

14:40 Optical Supramolecules for Microfluidic Sensing Devices

Christina M. RUDZINSKI and Daniel G. Nocera

Massachusetts Institute of Technology, Department of Chemistry, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, USA; nocera@mit.edu

15:00 Concluding Remarks

Hans Hofstraat, Philips Research and University of Amsterdam

Princeton Room, DoubleTree Hotel, Thursday November 19, + 3:00 PM - + 5:00 PM

Sponsored by SPEX industries from Instruments SA.

 

 

ABSTRACTS

 

Advances in the Design and Applications of Sensors Based on Luminescent Transition Metal Complexes

J.N. Demas, Wenying Xu and Kristi Kneas, Department of Chemistry, University of Virginia, Charlottesville, VA 22901, USA

B.A. DeGraff

Department of Chemistry, James Madison University, Harrisonburg, VA 22807, USA

A variety of inorganic complexes show great promise as molecular probes and luminescence-based sensors. The majority of work uses d⁶ systems Ru(II), Re(I), and Os(II) with a -diimine ligands (e.g., 2,2’-bipyridine, 1,10-phenanthroline, and analogues). Central to the rational design of practical systems is an intimate understanding of the interactions between the probe or sensor molecule and the polymer based support or the target. Advances in understanding the interactions of metal complexes and polymeric supports will be discussed using examples from oxygen and pH sensors. We conclude by pointing out that these areas are still in their infancy and that the ultimate goal of a totally rational design of probes, luminescence enhancers, and polymer-supported sensors is as yet an imperfectly realized goal.

Luminescence-Based Oxygen Sensors: Fluorescence Microscopy as a Probe of System Heterogeneity

Kristi A. Kneas and J.N. Demas

Department of Chemistry, University of Virginia, Charlottesville, VA 22901, USA

Ammasi Periasamy

Department of Biology, Advanced Cellular Imaging Facility, University of Virginia, Charlottesville, VA 22901, USA

B.A. DeGraff

Department of Chemistry, James Madison University, Harrisonburg, VA 22807, USA

Luminescence-based sensors, especially those based on platinum-group complexes, are of significant and growing practical importance. Sensors utilizing Ru complexes as the luminophore are now commercially available for measuring oxygen in blood and as pressure sensitive paints for wind tunnel studies. However, the detailed role of the polymer support in controlling photophysical behavior is still poorly understood. Since polymeric sensor heterogeneity has a tremendous effect on luminescence, quenching, and photochemistry, important questions are the types of sites occupied by the sensor molecules, the local environment, the quenching processes, and the correlation of these properties to different sensor supports. We will show that fluorescence microscopy is an invaluable tool in studying microheterogeneities within luminescence-based oxygen sensor films. Nonlinear Stern-Volmer plots and nonexponential luminescence decays are features of most all sensor systems, and resolution of microscopic inhomogeneities using fluorescence microscopy should allow the source of these nonlinearities to be determined and controlled. Such knowledge is critical to rational sensor design.

Enhancement of the Photoluminescence and Electroluminescence Quantum Yield in Molecular Dispersed Solid Thin Films

Hedi Mattoussi, Hideyuki Murata, Charles D. Merritt and Zakya H. Kafafi

Naval Research Laboratory, Optical Sciences Division, Washington, DC 20375, USA

We present measurements of the absolute photoluminescence quantum yield (f_PL) of a wide variety of organic compounds in thin (sub-micron) solid films, pure and molecularly doped with highly fluorescent guest molecules, using an integrating sphere. The films are prepared using high vacuum vapor deposition. They include a common hole transport material, bis (3-methylphenylphenylamino) biphenyl (TPD), and two electron transport metal chelates, tris-(8-hydroxyquinolinolato) aluminium(III) (Alq₃) and a methyl derivative of Alq₃ (Almq₃). These compounds are used pure and doped with either tetraphenylnapthacene (rubrene) or N,N-diethyl quinacridone (DEQ). The PL signal is generated either from the host, for pure compounds, or from the guest, via energy transfer, for molecularly doped films. For doped films, substantial enhancement (~ a factor 2-4) of f_PL is observed in comparison with the pure host. For example, measured f_PL increases from 25% for pure Alq₃ to near 100% upon doping with rubrene at ~ 1 mol%. The PL data are compared to the electroluminescence quantum efficiency (f_EL) of heterostructure devices, where these same composite films have been embedded between a hole and an electron transport layers and used for EL emission. A substantial improvement of f_EL with doping is observed, e.g., an enhancement of 100% is measured for f_EL with devices using rubrene doped Alq₃ at 1 mol%, in comparison with an undoped device. We will discuss the PL data within the framework of fluorescence lifetime and exciton transfer. Exciton transfer and migration, and carrier recombination will be used in addressing the EL of composite devices.

 Photoluminescence of Uranium Compounds

DeLyle Eastwood and Jeffrey B. Martin

Air Force Institute of Technology, 2950 P Street, Wright Patterson Air Force Base, OH 45433-7765, USA

Dale L. Perry

Mail Stop 70A-1150, Lawrence Berkeley National Laboratory, Berkeley, CA 94720

Photoluminescence spectroscopy can be used to gain valuable information concerning the bonding and chemistry of uranium and its compounds and complexes. Spectral data change as a function of the bonding in the coordination sphere about the uranium ion, with the number of compounds that can be studied by this technique being quite extensive. Typical coordination

spheres include uranium-oxygen, uranium-sulfur, and uranium-nitrogen linkages, all which have luminescence spectra that can be used to identify them.

This presentation will discuss luminescence spectroscopy of uranium as a function of the chemistry of the bonding and structure of the central uranium ion, including binary compounds such as oxides as well as complexes of oxygen, nitrogen, and sulfur.

This work was supported by Contract No. DE-AC03-76SF00098 from the U.S. Department of Energy.

Sensitizer-Functionalized Near-Infrared Emitting Lanthanide Complexes

Steve I. Klink, Frank C.J.M. van Veggel and David N. Reinhoudt, Laboratory of Supramolecular Chemistry and Technology and MESA Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands

Johannes W. Hofstraat

Akzo Nobel Central Research, Department RGL, P.O. Box 9300, 6800 SB Arnhem, The Netherlands; present address: Philips Research, Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands

Recently there is a growing interest in complexes of the near-infrared emitting lanthanide ions for applications in fluoroimmuno-assays, optical amplification and laser systems. The ultimate goal of our research is the development of polymer-based optical amplifiers based on near-infrared emitting lanthanide complexes.

Here we report the photophysical properties of novel triphenylene-functionalized Nd³⁺, Yb³⁺, and Er³⁺ complexes. The 1.Ln³⁺ complexes exhibit the typical line-like lanthanide emission upon excitation of the triphenylene antenna chromophore. Sensitized emission at 1540 nm is observed for 1.Er³⁺, at 880, 1060, and 1330 nm for 1.Nd³⁺, and at 980 nm for 1.Yb³⁺.

Figure 1: The triphenylene-functionalized lanthanide complexes based on the terphenyl building block.

Time-resolved luminescence measurements showed that the observed luminescence lifetimes of the complexes are in the range of microseconds, with the Yb³⁺ complexes having the longest lifetimes and the Nd³⁺ complexes the shortest. Our present results compare favorably to the recently published luminescence lifetimes of Nd³⁺ and Yb³⁺ complexes, and our previously published life times of Er³⁺.

Frank J. Steemers

Tufts University, Chemistry Department, 62 Talbot Avenue, Medford, MA 02155, USA

Esther G. Kerver, Willem Verboom and David N. Reinhoudt

Laboratory of Supramolecular Chemistry and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands

Erik B. van der Tol, Hendrik J. van Ramesdonk and Jan W. Verhoeven

Laboratory of Organic Chemistry, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands

The important role of lanthanide complexes as time-resolved luminescent labels in bioaffinity assays is related to their unique luminescence characteristics, e.g. long luminescent lifetimes (ms), large Stokes shifts (300-500 nm), and line-like emissions. A crucial aspect which determines the sensitivity of such labels is the sensitizer ("antenna") unit. Recently, we have reported on the synthesis and luminescence properties of (water-soluble) sensitizer-modified calix[4]arene lanthanide complexes.^1,2,3 In this paper a series of diaza-⁴ and tetraazatriphenylene derivatives⁵ is presented which constitutes a new and efficient class of sensitizers with significant complexing power for lanthanide ions.

  These azatriphenylenes form stable 2:1 sensitizer:lanthanide complexes in acetonitrile, simultaneously sensitizing the luminescence of different lanthanide ions. The very high luminescence quantum yields obtained for both Eu³⁺ and Tb³⁺ (up to 0.41 and 0.67, respectively) in combination with a suitable excitation window and the appreciable molar extinction coefficient of these azatriphenylenes at l > 330 nm, render these antenna chromophores very attractive for incorporation in luminescent lanthanide probes. Moreover, the azatriphenylene-based lanthanide complexes do not show fluorescence, and the lanthanide luminescence quantum yield and luminescence lifetime are insensitive to quenching by oxygen. This indicates fast and efficient energy transfer. Tetraazatriphenylenes are easily modified with a variety of substituents, allowing fine-tuning of the required photophysical characteristics. Finally, studies are presented which reveal a correlation between the lowest triplet state energy level of the azatriphenylene and the luminescence quantum yield of the lanthanide complexes. Energetic requirements and considerations for antenna chromophores with the lanthanide ions Eu³⁺ and Tb³⁺ are given.

References:

1. Steemers, F. J.; Verboom, W.; Reinhoudt, D. N.; van der Tol, E. B.; Verhoeven, J. W.; J. Am. Chem. Soc. 1995, 117, 9408.

2. Steemers, F. J.; Meuris, H. G.; Verboom, W.; Reinhoudt, D. N.; van der Tol, E. B.; Verhoeven, J. W.; J. Org. Chem. 1997, 62, 4229.

3. Grote Gansey, M. H. B.; Steemers, F. J.; Verboom, W.; Reinhoudt, D. N.; Synthesis 1997, 643.

4. a) Steemers, F. J.; Verboom, W.; Reinhoudt, D. N.; van der Tol, E. B.; Verhoeven, J. W.; Photochem. Photobio. A. 1998, 113 (2), 141. b) Patent: EP 97201236.3, April 25, 1997.

5. Van der Tol, E. B.; van Ramesdonk, H. J.; Verhoeven, J. W.; Steemers, F. J.; Verboom, W.; Reinhoudt, D. N.; Tetraazatriphenylenes as Extremely Efficient Antenna Chromophores for Lanthanide Ions, accepted for publication in Chem. Eur. J.

Terbium(III) as a Fluorescent Probe for the Elucidation of the Ion-Binding Properties and Degradation of Polyelectrolytes

Hannia Lujan-Upton, Yoshiyuki H. Okamoto and M.D. Cho

Long Island University, University Plaza, Brooklyn, NY 11201, USA

The terbium ion, Tb(III), is very sensitive to its coordinative environment. The introduction of hard ligands containing carbonyl moieties can enhance the fluorescence intensity and lifetime of the ion by displacing waters of coordination which normally quench the fluorescence. Subtle differences as local configurational differences in a polymer, tacticity, can be detected using the Tb(III) ion as a fluorescent probe. Small organic stereoisomers, when complexed with Tb(III) ion also can be differentiated from each other using this extremely sensitive probe. Finally, the sensitivity of Tb(III) ion can also be used to detect the onset of polymer degradation involving carbonyl chain end groups. Gamma irradiated polymers, once complexed with Tb(III) gave measurable differences in intensity before and after irradiation. Intensity differences were also dependent on irradiation time and the availability of an alpha hydrogen on the polymer backbone.

Shang Li, Timothy L. Vail, Jarrett L. Burton, Keith Kardos and R.Sam Niedbala

STC Technologies, Inc., 1745 Eaton Ave., Bethlehem, PA 18018-1799, USA

A novel class of inorganic luminescent materials have been developed as reporters for immunoassays. These ~ 0.4 mm particles, which up-convert infrared to visible light, provide several unique properties when applied to the detection of biological analytes. One key feature of these materials is that up- conversion does not occur in nature and therefore there is no inherent background. In order to utilize these particles, they must be modified for conjugation to biomolecules through specific functional groups (amine or carboxylic acid) on the surface of the inorganic crystalline particles. This presentation will review the strategies for synthesis, surface functionalization, and characterization of these new phosphorescent materials.

 Fluoresceindiaminotetracarboxylic Acid Derivatives as Efficient Sensitizers-Cum-Complexants for Near-IR Emitting Lanthanide Ions and their Diagnostic Application

Johannes W. Hofstraat

Akzo Nobel Central Research, Dept. RGL, P.O. Box 9300, 6800 SB Arnhem, The Netherlands; present address Philips Research, Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands, and University of Amsterdam, Institute of Molecular Chemistry, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands

Richard H. Woudenberg and Peter Emmerink

Akzo Nobel Central Research, Dept. RPH, P.O. Box 9300, 6800 SB Arnhem, The Netherlands

Martinus H.V. Werts and Jan W. Verhoeven

Laboratory of Organic Chemistry, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands

Europium (III) and terbium (III) based chelates are well-known for their long luminescence lifetimes and narrow emission bands. These properties are favorable for their use as luminescent labels in microscopy and in luminescence-based immunoassays, since they enable highly efficient removal of interfering signals like autofluorescence and scatter from biological material. When excitation is done via a strongly absorbing sensitizer sensitive detection can be achieved. A draw-back of these labels, which luminesce in the visible part of the spectrum, is that due to energy constraints the sensitizers have to be excited in the ultraviolet part of the spectrum. In the paper recently synthesized water-soluble lanthanide complexes will be presented, which are based on ytterbium (III), neodymium (III) and erbium (III) ions, which show luminescence in the near-infrared (with main emission bands at 980 nm, at 1060 nm and at 1520 nm, respectively), and which contain antenna chromophores that enable efficient excitation with visible light. Previously synthesized complexes, comprising polyaminocarboxylate ligands coupled to fluorescein-based chromophores, did show sensitized luminescence but with relatively low efficiency. A significant improvement in luminescence intensity could be realized by making use of fluoresceindiaminotetracarboxylate as sensitizer-cum-ligand. The photophysical properties of such luminescent lanthanide complexes, that combine long-wavelength excitability with long radiative lifetimes, will be shown and discussed, and a diagnostic application will be demonstrated.

Christina M. Rudzinski and Daniel G. Nocera

Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

We have prepared the first active site that is capable of producing a bright, visible light emission upon the recognition of polychlorinated biphenyl (PCB) and polyaromatic hydrocarbon (PAH) pollutants in aqueous environments. The optical supramolecule comprises a cyclodextrin (CD) docking site for analyte appended with a trianionic diethylenetriamine-pentaacetic acid (DTPA) binding site containing a lanthanide ion photoactive center. The mechanism for signal transduction has been recently defined by fast and ultrafast laser spectroscopy. Efforts to adapt the active site to patterned nanostructures by their introduction into polymer host matrices will be presented. The potential for the design of a functional microfluidic optical chemosensor based on this optical supramolecule archetype will be discussed.

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