ERROR opening https://cactus.nci.nih.gov/chemical/structure/c1cc%28%5BnH%5Dc1%29C%3DC2C%3DCC%3DN2/file?format=sdf&get3d=True -- c1cc%28%5BnH%5Dc1%29C%3DC2C%3DCC%3DN2 could not be loaded.