[{"from": "human", "value": "Create a molecule that satisfies the conditions outlined in the description. The molecule is a dicarboxylate that contains four carbon atoms. It is a conjugate base of a C4-dicarboxylic acid."}, {"from": "gpt", "value": "[C][=Branch1][C][=O][O-1].[C][=Branch1][C][=O][O-1]"}]