[{"from": "human", "value": "Create a molecule that satisfies the conditions outlined in the description. The molecule is a nitrogen mustard alkylating agent that causes DNA cross linkages. It is a known carcinogen especially in mice. (NCI)"}, {"from": "gpt", "value": "[C][N+1][Branch1][Ring2][C][C][Cl][Branch1][Ring2][C][C][Cl][O-1].[Cl]"}]