[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is dicarboxylate anion of 3-ethylmalic acid. It is a conjugate base of a 3-ethylmalic acid."}, {"from": "gpt", "value": "[C][C][C][Branch1][#Branch2][C][Branch1][=Branch1][C][=Branch1][C][=O][O-1][O][C][=Branch1][C][=O][O-1]"}]