Professor A. Vlcek, RNDr(Prague) CSc(Prague)

Professor of Inorganic Chemistry

School of Biological & Chemical Sciences
Queen Mary, University of London
Walter Besant Building, Mile End Road
London
E1 4NS
Tel: +44 (0) 20 7882 3260
Fax: +44 (0) 20 7882 7427
email: A.Vlcek@qmul.ac.uk

Photos of the San Feliu D14 Meeting.

Research Interests

Ultrafast excited-state dynamics of transition metal complexes and organometallics. Chemical and physical consequences of optical excitation into charge-transfer electronic transitions are investigated by a combination of state-of-the-art laser spectroscopic techniques, namely femtosecond time-resolved UV-visible absorption, picosecond time-resolved IR absorption, resonance Raman and visible emission. The results are interpreted using TD-DFT calculations. Vibrational relaxation, metal-ligand bond splitting, intramolecular electron and energy transfer and intraligand isomerization are studied in detail. This research aims at identifying new ultrafast (photo)chemical pathways and, especially, at revealing and understanding the relations between molecular structure, excited-state character and dynamics. Enabling knowledge for possible applications in optical molecular materials (molecular electronics/photonics, information storage, sensors and probes).

Identification and characterization of new types of excited states. Laser time-resolved spectroscopic techniques are used to characterize structural changes upon electronic excitation of transition metal complexes. Experimental results are compared with accompanying electron density redistribution and molecular vibrations calculated by TD-DFT and DFT techniques, respectively. Unprecedented details about excited-state characters are obtained and used to develop new molecular optical components or probes. This research already led to revision of some well established "textbook truths", such as the spectroscopic, photochemical and photophysical roles of ligand-field and charge-transfer-to-CO excited states in mixed-ligand metal carbonyls.

Dynamics of structural and dynamical molecular probes. Emission properties of some organometallic complexes are known to be highly sensitive toward the medium. Specific ligands can be used to bind such complexes to proteins, DNA and other important biomolecules. We are now beginning investigations of molecular origins of these interactions and newly extending these studies to understand and explore dynamical coupling between metal-containing chromophores and their environment (solvent, polymer matrix, protein, molecular host).

Selected Recent Publications

• Mechanism and Dynamics of Interligand Electron Transfer in [Re(MQ+)(CO)3(dmb)]2+. An Ultrafast Time-Resolved Visible, IR Absorption, Resonance Raman and Emission Study (dmb = 4,4'-dimethyl-2,2'-bipyridine, MQ+ = N-methyl-4,4'-bipyridinium).
  Liard, D.J.; Busby, M.; Farrell, I.R.; Matousek, P.; Towrie, M.; Vlcek, A., Jr. J. Phys. Chem. A 2004, 108, 556-567.

• Molecular Structures of Electron-Transfer-Active Complexes [Re(XQ+)(CO)3(NN)]2+ (XQ+ = N-Me-4,4'-bipyridinium or N-Ph-4,4'-bipyridinium; NN = bpy, 4,4'-Me2-2,2'-bpy or N,N'-bis-isopropyl-1,4-diazabutadiene in the Solid State and Solution. An X-Ray and NOESY NMR Study.
  Busby, M.; Liard, D.J.; Motevalli, M.; Toms, H.; Vlcek, A., Jr. Inorg. Chim. Acta 2004, 357,167-176.

• Solvent-Dependent Dynamics of the MQ•—ReII Excited-State Electron Transfer in [Re(MQ+)(CO)3(dmb)]2+.
  Liard, D.J.; Kleverlaan, C.J.; Vlcek, A., Jr. Inorg. Chem. 2003, 42, 7995-8002.

• The Involvement of Metal-to-CO Charge Transfer and Ligand-Field Excited States in the Spectroscopy and Photochemistry of Mixed-Ligand Metal Carbonyls.
  A Theoretical and Spectroscopic Study of [W(CO)4(1,2-ethylenediamine)] and [W(CO)4(N,N'-bis-Alkyl-1,4-diazabutadiene)].
  Záliš, S; Farrell, I.R.; Vlcek, A., Jr. J. Am. Chem.Soc. 2003, 125, 4580-4592.

• Direct Observation of Competitive Ultrafast CO Dissociation and Relaxation of an MLCT Excited State: Picosecond Time-Resolved Infrared Spectroscopic Study of [Cr(CO)4(2,2'-bipyridine)].
  Farrell, I.R.; Matousek, P.; Towrie, M.; Parker, A.W.; Grills, D.C.; George, M.W.; Vlcek, A., Jr. Inorg. Chem. 2002, 41, 4318-4323.

• Highlights of the Spectroscopy, Photochemistry and Electrochemistry of [M(CO)4(alpha-diimine)] Complexes, M = Cr, Mo, W.
  Vlcek, A., Jr. Coord. Chem. Rev. 2002, 230, 225-242.

• Early Photochemical Dynamics of Organometallic Compounds Studied by Ultrafast Time-Resolved Spectroscopic Techniques.
  Vlcek, A., Jr.; Farrell, I.R.; Liard, D.J.; Matousek, P.; Towrie, M.; Parker, A.W.; Grills, D.C.; George, M.W. J. Chem.Soc., Dalton Trans. 2002, 701-712.

• UV-Vis Absorption Spectra of [Ru(E)(E')(CO)2(iPr-DAB)] (E = E' = SnPh3 or Cl; E = SnPh3 or Cl, E' = CH3; iPr-DAB = N,N'-di-isoPropyl-1,4-diaza-1,3-butadiene): A Combination of CASSCF/CASPT2 and TD-DFT Calculations.
  Turki, M.; Daniel, C.; Záliš, S.; Vlcek, A., Jr.; van Slageren, J.; Stufkens, D.J. J. Am. Chem. Soc. 2001, 123, 11431-11440.

• Electrochemical Oxidation of [Cr(CO)4(tmp)] to the Low-Spin Cr(I) Species [Cr(CO)4(tmp)]+ (tmp = 3,4,7,8-tetramethyl-1,10-phenanthroline): An IR, UV-Vis, and EPR Spectroelectrochemical and DFT Computational Study of the Accompanying Changes in Molecular and Electronic Structure.
  Farrell, I.R.; Hartl, F.; Záliš, S.; Wanner, M.; Kaim, W; and Vlcek, A., Jr. Inorg. Chim. Acta 2001, 318, 143-151.

• Time-Resolved Emission Spectra and TD-DFT Excited-State Calculations of [W(CO)4(1,10-phenanthroline)] and [W(CO)4(3,4,7,8-tetramethyl-1,10- phenanthroline)]
  Farrell, I.R.; van Slageren, J.; Záliš, S.; Vlcek, A., Jr. Inorg. Chim. Acta 2001, 315, 44-52.

• Electron Transfer Processes in Mononuclear Polypyridine Metal Complexes.
  Vlcek, A., Jr. Electron Transfer in Chemistry. Wiley-VCH, Weinheim (Germany): 2001. p. 804-877.

• Photoreactivity of Cr(CO)4(2,2'-bipyridine): Quantum Chemistry and Photodissociation Dynamics.
  Guillaumont, D.; Daniel, C.; Vlcek, A., Jr. J. Phys. Chem. A 2001, 105, 1107-1114.

• The Spectroscopic, Electrochemical and Photophysical Effects of the b1/a2 pi* Lowest Unoccupied Molecular Orbital Switching in [M(CO)4(N,N)] (M = Cr, W; N,N = 1,10-phenanthroline or 3,4,7,8-tetramethyl-1,10-phenanthroline). An Experimental and DFT Computational Study.
  Farrel, I.R.; Hartl, F.; Záliš, S.; Mahabiersing, T.; and Vlcek, A., Jr. J. Chem. Soc., Dalton Trans. 2000, 4323-4331.

• Mechanisms of Ultrafast M-L Bond Splitting upon MLCT Excitation of Carbonyl-Diimine Complexes.
  Farrell, I.R.; Vlcek, A., Jr. Coord. Chem. Rev. 2000, 208, 87-101.

• The Life and Times of Excited Organometallic Molecules.
  Vlcek, A., Jr. Coord. Chem. Rev. 2000, 200-202, 933-937.

• Ultrafast Dynamics of Photochemical Radical Formation from Re(R)(CO)3(dmb) (R = Me or Et, dmb = 4,4'-dimethyl-2,2'-bipyridyl): A Femtosecond Time-Resolved Visible Absorption study.
  Farrell, I.R.; Matousek, P.; Kleverlaan, C.J.; Vlcek, A., Jr. Chem.-Eur. J. 2000, 6, 1386-1394.

   

   

   

   

   

   

   

   

   

   

   

   

   

  
  

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