BIOVIA Direct 2021 might create invalid molfiles for structures with zero order bonds Markush bonds and haptic pi bonds created in previous versions of Direct

DB 2021-04-29

We like to report an issue with BIOVIA Direct 2021 that might occur when you create molfiles from BIOVIA Direct binary CTABs that were created in previous versions of BIOVIA Direct. The issue in particular occurs with structures that contain zero-order bonds, Markush bonds, and haptic (pi) bonds. The molfiles created through several BIOVIA Direct 2021 operators are missing the definitions for these bond types and are formally invalid. The problem also applies to chimestrings, rxnfiles, and rxnchimes. The following BIOVIA Direct 2021 operators are impacted:

chime, molchime, mdlaux.molchime
chime_string
chime_string_seq
molfile, mdlaux.molfile
molfile_string
molfile_string_seq
rxnfile
rxnchime
rxnmol
rxnstringsegment

The issue is tracked as bug DIR-4142 and is specific to Direct 2021. It is resolved in the upcoming BIOVIA Direct 2021 SP1 release, scheduled for May 2021.