Research Highlights

Current and Past Research Projects at CATCO in Short

  1. Method development
  2. Molecular Properties
  3. Chemical Substance Classes
  4. Drug Design and Biochemically Relevant Topics
  5. Heuristic Models
  6. Chemical Disciplines
  1. Method Development

    1. Density Functional Theory for Multi-Reference Systems
      Broken-Symmetry UDFT, Restricted Open-Shell Singley (ROSS)-DFT, Restricted Ensemble Kohn-Sham (REKS)-DFT, Complete Active Space (CAS)-DFT; Investigation of the problem of double counting of correlation effects.
    2. Self-Interaction Corrected (SIC) DFT
      Investigation of the self-interaction error; SIC-DFT for small and large molecules; correct description of odd-electron bonds; investigation of the XC hole; intraelectronic and interelectronic exchange effect.
    3. DFT Calculation of Magnetic Properties
      DFT methods for calculating magnetic shieldings and magnetizabilities; DFT methods for calculating spin-spin coupling constants; relativistic corrections for magnetic shieldings and spin-spin coupling constants.
    4. Investigation of the Spin-Spin Coupling Mechanism
      Development of the J-OC-PSP method (decomposition of J into orbital contributions using orbital currents and partial spin polarization); investigation of Fermi contact coupling, spin dipole coupling, paramagnetic and diamagnetic spin-orbit coupling; influence of p-electrons on the coupling mechanism; graphical representation techniques of Ramsey spin densities and energy densities.
    5. Relativistic Theory
      Development of quasirelativistic methods to be used for DFT, MBPT, and Coupled Cluster theory; gauge-independent ZORA and IORA; IORAmm; relativistic calculation of geometries, electric properties, magnetic shielding ESR-hyperfine spin coupling constants and NMR spin-spin coupling constants using analytical energy derivatives.
    6. Many Body Perturbation Theory - Highly Correlated WFT Methods
      MP5 and MP6, approximate MP6, Convergence of the MPn series, quasi-degenerate perturbation theory, GVB-MP, gradient techniques, scaling methods.
    7. Coupled Cluster Methods - Highly Correlated WFT Methods
      Role of T and Q effects (CCSDT, CCSDTQ), size-extensive QCISDT, QCISDTQ; CC methods correct in sixth order; spin-projected CC.
    8. Methods for Analytical Gradients
      MP gradients and CC gradients, gradients for GVB-MP; gradients for relativistic methods.
    9. Development of QM/MM methods
      Problem of the dangling bonds; force fields for specific molecules; inclusion of methods developed under 1.1 and 1.5.
    10. Methods for Analyzing and Correlating Vibrational Spectra
      Development of methods to determine local adiabatic modes; adiabatic mode analysis; methods for the correlation of vibrational spectra; and CNM (characterization of normal mode) methods.
    11. Methods for Calculating Conformational Changes
      Ring puckering coordinates; coordinates for describing bond pseudorotation; development of potential functions for puckered rings, geminal double rotors, etc.; DORCO: determination of ring conformations via NMR spin-spin coupling constants in an automated way; derivation of generalized Karplus curves.
    12. Methods for Investigation of the Dynamics of a Chemical Reaction
      Extension of the Reaction Path Hamiltonian and the reaction valley approach; analysis of the reaction path curvature and mode coupling; direct reaction dynamics; URVA: united reaction valley approach.
  2. Molecular Properties

    1. Calculation of Molecular Geometry and Conformation
      Using correlation corrected WFT methods or DFT; investigation of pseudorotating rings.
    2. Calculation of Energetic Properties
      Using correlation corrected WFT methods or DFT; investigation of potential energy surfaces of small molecules; determination of thermochemical properties.
    3. Calculation of Electron Density Distributions
      Using correlation corrected WFT methods or DFT; topological analysis and virial partitioning; investigation of energy density distribution and Laplace concentration.
    4. Calculation of Properties of the Vibrating Molecule
      Using correlation corrected WFT methods or DFT; calculation of harmonic vibrational frequencies and infrared intensities; isotope effects; local mode analysis.
    5. Calculation of Magnetic Properties
      Calculation of magnetic shieldings and chemical shifts using HF-IGLO, DFT-IGLO, GIAO or GIAO-MP methods; calculation of magnetic susceptibilities and susceptibility exaltations; CC and DFT calculation of spin-spin coupling constants.
  3. Chemical Substance Classes

    1. Investigation of Carbocations
      NMR chemical shifts in gas phase and solution, stability, structure, reactivity; aromatic and homoaromatic carbocations; application of NMR/ab initio/chemical shift methods.
    2. Investigation of Silyl Cation
      Structure and stability, calculation of 29Si chemical shifts, silylium cations, investigation of silylium cations in solution (interactions with solvents), bonding in silylium cation-solvent complexes.
    3. Investigation of Peroxides and Polyoxides
      Investigation of the ozonolysis of alkenes and alkines; ozonides, organic and inorganic peroxides, carbonyl oxides and dioxiranes; carbene-oxygen reactions.
    4. Investigation of Strained Molecules
      Three-membered rings in particular cyclopropyl derivatives; anti-Bredt compounds; theory of ring strain; steric repulsion and steric attraction (cis-effect).
    5. Investigation of Biradicals
      Structure and stability of dehydrobenzenes; products of the Myers cyclization; dioxymethanes; oxythiamethanes.
    6. Investigation of Tin Compounds
      Structure and stability of stannanes and stannyl cations; calculation of d119Sn chemical shifts; free stannylium cations in solution.
    7. Investigation of van der Waals Complexes
      Structure and stability of Ar-complexes with aromatic molecules; oxygen and ozone complexes with alkenes and aromatic molecules; electron density description.
    8. Investigation of Frozen Transition States
      Stabilization of transition states by substituents; homoaromatic carbocations; substituted semibullvalenes.
  4. Drug Design and Biochemically Relevant Topics

    1. Investigation of Naturally Occurring Enediynes
      Structure and stability of triggered and un-triggered dynemicin; stereoisomers of calicheamicin; investigation of its aglycone.
    2. Development of a New Antitumor Drug
      Development of a drug design strategy; new warheads for enediynes; pH-dependence of the triggering of the warhead; construction of the real drug; favorable docking modes; calculation of binding energies; determination of DNA cleavage sites.
    3. Susceptibility of Proteins to Enediyne Ligands
      Protein damage as an alternative to DNA cleavage; design of proteinophilic enediynes.
    4. Generation of Acrylamid in Food
      Condition, mechanism, genotoxicity, carcinogenicity and adduct formation, investigation of the Maillard reaction.
    5. Investigation of the Nerve Gases Sarin and Soman
      Structure, stability and toxicity; detection by NMR spectroscopy.
    6. Toxin Ricin - One of the Most Toxic Compounds
      Investigation of the possibility to use this compound as new anticancer drug.
    7. Virtual Screening
      Encoding of chemical information in bit strings.
    8. Investigation of the Anti-Malarial Drug Artemisinin
      Stability and conformation; lability of the peroxidic group; reactions with Fe ions; reaction with the heme group.
  5. Heuristic Models and Concepts

    1. Theory of the Chemical Bond
      Electron Density Analysis, Investigation of Laplace concentrations and energy density distributions; derivation of bond properties from vibrational frequencies and infrared intensities.
    2. Concept of Aromaticity and Homoaromaticity
      Problem of selecting references; description with geometric, energetic and magnetic properties of molecules; electron density description; s-aromaticity.
    3. Concept of Molecular Strain
      Calculation of molecular geometries for gas and solution phases; calculation of infrared and NMR signals based on ab initio and DFT optimized geometries.
  6. Chemical Disciplines

    1. Structure Elucidation of Molecules
      Calculation of molecular geometries for gas and solution phases; calculation of infrared and NMR signals based on ab initio and DFT optimized geometries.
    2. Stability Analysis of Molecules
      Rationalization of molecular stability by conjugation, hyperconjugation, anomeric effect, homoconjugation, etc. using MO models and electron density distribution.
    3. Elucidation of Reaction Mechanism
      Pericyclic reactions in particular [2+2] and [4+2] cycloadditions; valence isomerization, substitution reactions, solvent effects; energy transfer and energy dissipation; Bergman and Myers cyclization; ozonolysis reaction and other oxidation reactions.
    4. Solvation and Solvent Effects
      Geometries, energies and magnetic properties of molecules in solution; interactions of carbocations and silylium cations with various solvents.
    5. NMR Spectroscopy
      NMR chemical shifts by IGLO, GIAO, SOS-DFT, magnetic susceptibilities, NMR/ab initio/Chemical Shift methods for the determination of molecular geometries in solution, correlation between spin-spin coupling constants and molecular geometry; Karplus curves.
    6. Infrared Spectroscopy, in particular Matrix Isolation Spectroscopy
      IR determination of labile compounds, reaction mechanism, adiabatic analysis.
    7. Microwave Spectroscopy
      Investigation of argon van der Waals complexes; investigation of ozone complexes.
    8. Inorganic Chemistry
      Investigation of tin compounds: stannanes, stannylium cations; investigation of sulfur compounds: sulfanes, organo sulfur compounds; investigation of Ti compounds.
    9. Biochemistry
      Anticancer drugs, reaction mechanism enediyne cytostatica and antibiotics; Bergmann and Myers cyclizations; structure and stability of biradicals that attack DNA.
    10. Reaction Dynamics
      Reaction Path Hamiltonian, Direct dynamics, RRKM calculations; adiabatic mode analysis, electron density analysis; investigation of substitution reactions; investigation of pericyclic reactions.
    11. Atmospheric Chemistry
      OH production, Ozonolysis, Carbonyl oxides, reaction mechanism, dioxirane reactions.