iSpartan

iSpartan is a versatile app for molecular modeling on the iPad, iPhone, and iPod Touch. The app allows any chemist fast and easy access to computational methods that have proven reliable for a large range of molecules.

Molecules are created by two-dimensional sketching, analogous to drawing a structure on paper. The app converts the two-dimensional sketch into a three-dimensional structure. Low-energy conformations can then be calculated and their geometries be queried. A database of 5,000 molecules (a subset of the Spartan Spectra and Properties Database, SSPD) can furthermore be accessed to obtain NMR and IR spectra, molecular orbitals, electrostatic potential maps, and other atomic and molecular properties. The database can be searched for substructures.

Conformational analysis:
• Identify the most favorable conformer
• Assess alternative energy conformers
• Present the results in a clear energy diagram
iSpartan uses the proven MMFF force field and performs conformational searching in real time.

Properties available for any molecule:
• R / S chirality
• Molecular weight
• Total surface area and polar surface area
• Molecular volume
• Log P
• Vicinal coupling constants
• Distances, angles, and torsion angles

Spectra and other properties calculated using quantum mechanics are available for the 5,000 molecules in the database that is included with iSpartan. For common organic molecules, quantum chemistry calculations can be carried out if the Spartan Parallel Suite program is installed (separate product; available for Windows or Macintosh). Spartan Parallel Suite also provides access to the full SSPD (> 250,000 molecules) via the iPad, iPhone, or iPod Touch.

NMR spectroscopy:
• Assign peaks in proton and carbon spectra
• Confirm or reject structure predictions
• Suggest which structure is most consistent with the data
• Explore and suggest alternative structures
iSpartan combines the results of density functional calculations (EDF2/6-31G* model) with an empirical correction to obtain highly accurate spectra. Unlike purely empirical schemes, iSpartan always fully accounts for both 3D structure (stereochemistry) and conformation.

Thermochemistry:
• Identify the best tautomer or isomer
• Assess product distributions at equilibrium
• Classify reactions as endothermic or exothermic
iSpartan obtains the total energy from DFT calculations. The heat of formation of most organic molecules can also be estimated using the highly accurate T1 thermochemical recipe.

Infrared spectroscopy:
• Assign absorption bands to functional groups
• Confirm or reject structure predictions
• Animate molecular vibrations associated with the absorption bands
The shown spectrum is based on DFT calculations and includes a scaling factor for the frequencies. Temperature effects are accounted for by broadening of the absorption bands. The result is an accurate and realistic spectrum similar to experimental data.

Molecular orbitals and electrostatic potential maps:
• Analyze frontier orbitals in order to predict reactivity
• Use electrostatic potential maps to assess selectivity, reactivity, and acid strength and to distinguish between polar (hydrophilic) and nonpolar (hydrophobic) regions

Other calculated properties:
• Partial charges of atoms
• Dipole moments

Greater productivity in chemical research through molecular modeling...this is iSpartan.