[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is major species at pH 7.3."}, {"from": "gpt", "value": "[C][C][C][Branch1][C][C][S][P][=Branch1][C][=O][Branch1][C][O-1][S][C][Branch1][C][C][C][C]"}]