Dr. F. Parodi  -  Industrial R&D SuperExpert

Expertise & Know-How:  Computational Chemistry & Modeling

Calculation of Physical and Chemical Properties of Original & Novel Organic Compounds

Computation of molecular properties of novel, not yet or not-enough investigated organic compounds, as well as unstable or inaccessible reaction intermediates, in the gas phase or in solution, at any desired temperature:

• dipole moments and polarizability;

• heats of formation and dissociation;

• ionization potentials;

• protonation and de-protonation enthalpies;

• atomic charges, electrostatic potential (3D contour maps), and energies of molecular orbitals (in particular, HOMO & LUMO frontier orbitals, for the identification of specific, preferential reaction sites, etc.);

• main UV-visible and IR absorption frequencies, etc.;

• simulation of multinuclear NMR spectra (¹H, ¹³C, ¹⁵N, ¹⁵O, ¹⁹F, ³¹P).

Analysis of molecular properties under the influence of electric and/or magnetic fields with predetermined direction and intensity;  calculations of molecular polarizability (mean value and tensor components).  Building and analysis of polymeric and crystal structures.

Usage of a range of computational chemistry methods:

• molecular mechanics, under various force fields (primarily, MM+ and BIO+);

• semi-empirical quantum mechanics (principal methods adopted:  MNDO, AM1, PM3, ZINDO/1, and ZINDO/S);

• ab initio and Density Functional quantum mechanics, under a choice of basis sets for calculation of molecular orbitals by linear combination of atomic orbitals from H to Xe  (i.e., by STO-nG, n-21G & n-31G orbital basis sets, etc.).

Properties computed for predetermined molecular conformations.  Average, equilibrium values obtained via molecular dynamics or Monte Carlo simulations.  Compounds in solution investigated via Langevin dynamics simulations.

Computer-aided, quantum-mechanical modeling of organic reactions:

• calculation of reaction enthalpies, and identification of thermodynamically-favored reactions;

• semi-empirical quantum-mechanical simulation of reaction pathways via electrophile-nucleophile and/or frontier molecular orbitals interactions:

• simulation of the entire profile of concurrent reactions and alternative mechanisms;

• identification and simulation of reaction intermediates, activated complexes, etc.;

• comparative evaluation of potential reaction kinetics via the Klopman-Salem approach (electrostatic interactions + overlapping of frontier HOMO/LUMO molecular orbitals);

• calculation of activation energies by ab initio quantum mechanics;

• analysis of mechanisms of homogeneous catalysis and solvation effects (and prediction of optimal solvents), etc.

Calculation of Physical and Chemical Properties of Original & Novel Polymeric Substances

• computer-aided calculation of physical properties of novel or modified polymers and polymer blends, via QSPR methods:

• density and refractive index;

• melting & glass transition temperatures;

• solubility parameters;

• surface energy;

• dielectric constant;

• elastic properties, etc.

• chemical properties of specific molecular portions or polymer back-bone sites, investigated by semi-empirical quantum-mechanical simulations:

• mechanisms and energies of radical chain scission and depolymerization;

• identification of  back-bone sites preferentially reactive toward various co-reactants, and simulation of possible reactions (hydrolysis, trans-esterification and -amidation, hydrogen abstraction and free-radical grafting, etc.);

• intra- and intermolecular hydrogen-bonding energies, solvation enthalpies,  etc.

Molecular simulations and data processing carried out on Pentium IV ^® 3.2 and 2 GHz (Intel, Inc.) workstations  [under Windows 2000 Professional^® or Windows XP Professional^® (Microsoft Corp.), as the operating system]

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