New features MOLGEN 3.5

Hydrogen distribution

The analysis of NMR speturesctra often provides information on the degree of substitution of a compound, i.e. on the number of H-atoms connected to carbon or hetero atoms. This information can now be used in MOLGEN to drastically reduce the number of isomers constructed from the given molecular formula. So the user may optionally input the hydrogen distribution of the carbon, nitrogen and oxygen atoms. For example, in the previous version it was possible that a prescribed CH2 subgroup with two free valences could get another hydrogen leading to a CH3 subgroup during the construction process. The input dialog is


Hybridization

MOLGEN 3.5 will furthermore allow to make use of another important result of NMR spectroscopy, i.e. to optionally input the hybridization states of carbon and hetero atoms, which also considerably reduces the number of isomers that must be generated and checked. It will again be possible to give the exact distribution of the hybridization states or to enter just intervals. A draft of the input window is depicted here:


The following table shows the effect of using these new features of hydrogen distribution and hybridization:

Restrictions No. of Isomers CPU-time
Chemical formula C6H8O6 only 2,558,517 240s
No triple bonds 2,434,123 204s
No O-O 360,594 390s
Hydrogen distribution 1 CH2, 2 CH, 3 C, 4 OH 35,058 10s
Hybridization 1 Csp3-2H, 2 Csp3-1H, 3 Csp2-0H, 1 Osp2-0H 990 0.5s
Minimal ringsize 5 348 0.7s

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