Hula-twist mechanism

{
  "id": "MLC-T-CHM-005415",
  "term": "Hula-twist mechanism",
  "field": "Chemistry",
  "definition": "A volume-conserving mechanism of photoisomerization about a double bond within a conjugated chain, in which that bond and the adjacent single bond rotate together in one concerted motion, so configurational and conformational isomerization occur at the same time. Because only a small part of the chain moves, it needs far less free volume than the conventional one-bond-flip rotation and has been proposed for the retinal chromophore of visual pigments.",
  "synonyms": [
    "HT mechanism"
  ],
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "chromophore",
    "isomerization",
    "one-bond-flip",
    "photoisomerization"
  ],
  "references": [
    "PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 352 (https://doi.org/10.1351/pac200779030293)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/hula-twist-mechanism/"
}