Neu in Spartan

Nachfolgend finden Sie die jeweils neuen Features von Spartan in der aktuellsten Version.

Neu in Spartan 20

Neu in Spartan 20

Generate Isomers

A new tool provides automatic stereoisomer/regiosiomer elaboration. The input consists of a single molecule (isomer) with appropriate markers to indicate centers to be inverted (leading to stereoisomers) and bonds to be modified (leading to regioisomers). The result is a list of isomers. This list can then be submitted as an:

  • Equilibrium Conformer calculation leading to a list of the best conformer of each isomer.
  • Conformer Distribution calculation leading to Boltzmann-weighted conformer lists for each isomer.
  • NMR calculation leading to DP4 scores for each isomer after Boltzmann averaging over available conformers.

Isomer Generation Tool

The isomer generation tool has also been extended to transition states that lead to isomeric products.

NMR - Boltzmann-averaged NMR

A new, simplified, and order of magnitude faster protocol for comparing calculated and experimental NMR chemical shifts for conformationally-flexible molecules has been implemented. This replaces the accurate calculation of Boltzmann weights (the slow step in the protocol released in Spartan’18) by choosing from among “reasonable” low-energy conformers providing proton and 13C chemical shifts that best match experimental values.

An important use of NMR spectroscopy by synthetic chemists is to establish stereochemistry and/or regiochemistry for a “known” reaction. By combining automatic isomer generation with previous or new protocols for dealing with conformationally-flexible molecules, Spartan’20 can do this in a single step, starting with a single conformer of one isomer and resulting in proton and 13C chemical shifts that have been properly conformationally averaged or, in the case of the new protocol, best fit the experimental data, for each of the isomers. The DP4 score can then be examined to decide which isomer best fits the experimental proton and/or 13C chemical shifts. Single step access to the original Goodman DP4 recipe has also been implemented.

Coupling Constants

Empirical relationship for 2 and 3-bond CH coupling constants based on comparisons of calculated coupling constants with experimental data. Whereas, empirical (Karplus-like) relationships for 3-bond HH coupling constants have long been available, this provides (to our knowledge) previously unavailable and analogous but more complicated relationships for CH coupling constants.

2D NMR Spectra

2D NMR spectra, COSY (proton vs. proton) and HMBC (13C vs. proton), based on calculated chemical shifts and either calculated or empirical estimated HH and CH coupling constants. Observed HH and CH couplings may be entered and the resulting calculated and (simplified) experimental COSY and HMBC spectra visually compared.


  • Natural Products Database
    A Database of natural products with conformationally averaged calculated (from the protocol introduced with Spartan’18) NMR spectra and experimental spectra. This now comprises ~3,500 compounds and continually updated with new literature.
  • SSPD (Spartan Spectra & Properties Database)
    The SSPD subset (installed automatically with the program) has been expanded to include IR frequencies from the ωB97X-D/6-31G* model structures. The full 300,000+ database (separate installation) now includes energies from the ωB97X-V/6-311+G(2df,2p) energies (as a property). These energies are accessible from the Molecule Properties and the Reactions dialogues.

Parallel Processing

Aside from NMR and frequencies, we have made improvements to parallel performance which previously saw a performance plateau at around 10 cores. This now begins to plateau at around 15 cores (energy and geometry calculations). The plateau will become more and more relevant as the number of cores in chips that are readily available continues to increase (32 and 64 core chips are now available and this is likely to extend to 128 and 256 core chips in the not too distant future. Modest improvements to parallel performance of the frequency code have been implemented. Future development efforts include improved parallelization of the NMR code.

Graphical Interface

  • 2D Drawings
    Changes have been made to the 2D Sketch builder to allow an alternative option for increasing bond count (single to double, double to triple), and to designate stereochemistry via wedges. Experimental proton and 13C chemical shifts and HH and CH couplings may now be attached to 2D drawings.
  • Measure Distance
    A change has been made to allow distances inside rings to be changed in a single step.
  • Output Summary
    This HTML presentation format has been improved resulting in an order or magnitude (or more) speed increase as some data tables are calculated on-the-fly upon opening.

Computational Enhancements

  • Double Hybrid Functional
    The ωB97M(2) double hybrid functional has been added for energy calculations only.
  • Spartan’20 will take advantage of up to 16 cores for parallel jobs, with the option to license >16 cores as well (for high performance multicore systems), and will include the implementation of the latest Q-Chem version (5.2.1 at the time this list was compiled) and is the result of continued collaboration (begun with the release of Spartan’02 in 2002). Through this collaboration customers benefit from both GUI and computational enhancements in the Spartan code-base, as well as a growing range of computational approaches and modern computational methods included in Q-Chem.