ERROR opening https://cactus.nci.nih.gov/chemical/structure/C%28%23N%29C%28%3DC%28C%23N%29C%23N%29C%23N/file?format=sdf&get3d=True -- C%28%23N%29C%28%3DC%28C%23N%29C%23N%29C%23N could not be loaded.