The reaction of thiourea and 1,3‐dimethylthiourea towards organoiodines: oxidative bond formation and halogen bonding

• Published in: Acta crystallographica. Section C, Crystal structure communications Crystal structure communications, 2021-10, Vol.77 (10), p.599-609
• Main Authors: Peloquin, Andrew J., Ragusa, Arianna C., McMillen, Colin D., Pennington, William T.
• Format: Article
• Language: English
• Subjects: Acetone; Chemical bonds; crystal structure; dimethylthiourea; Ethanol; halogen bonding; hydrogen bonding; Iodides; Solid state; thiourea; Thioureas
• ISSN: 2053-2296; 0108-2701; 2053-2296; 1600-5759
• DOI: 10.1107/S205322962100869X

By varying the halogen‐bond‐donor molecule, 11 new halogen‐bonding cocrystals involving thiourea or 1,3‐dimethylthiourea were obtained, namely, 1,3‐dimethylthiourea–1,2‐diiodo‐3,4,5,6‐tetrafluorobenzene (1/1), C6F4I2·C3H8N2S, 1, thiourea–1,3‐diiodo‐2,4,5,6‐tetrafluorobenzene (1/1), C6F4I2·CH4N2S, 2, 1,3‐dimethylthiourea–1,3‐diiodo‐2,4,5,6‐tetrafluorobenzene (1/1), C6F4I2·C3H8N2S, 3, 1,3‐dimethylthiourea–1,3‐diiodo‐2,4,5,6‐tetrafluorobenzene–methanol (1/1/1), C6F4I2·C3H8N2S·CH4O, 4, 1,3‐dimethylthiourea–1,3‐diiodo‐2,4,5,6‐tetrafluorobenzene–ethanol (1/1/1), C6F4I2·C3H8N2S·C2H6O, 5, 1,3‐dimethylthiourea–1,4‐diiodo‐2,3,5,6‐tetrafluorobenzene (1/1), C6F4I2·C3H8N2S, 6, 1,3‐dimethylthiourea–1,3,5‐trifluoro‐2,4,6‐triiodobenzene (1/1), C6F3I3·C3H8N2S, 7, 1,3‐dimethylthiourea–1,1,2,2‐tetraiodoethene (1/1), C6H16N4S2·C2I4, 8, [(dimethylamino)methylidene](1,2,2‐triiodoethenyl)sulfonium iodide–1,1,2,2‐tetraiodoethene–acetone (1/1/1), C5H8I3N2S+·I−·C3H6O·C2I4, 9, 2‐amino‐4‐methyl‐1,3‐thiazol‐3‐ium iodide–1,1,2,2‐tetraiodoethene (2/3), 2C4H7N2S+·2I−·3C2I4, 10, and 4,4‐dimethyl‐4H‐1,3,5‐thiadiazine‐3,5‐diium diiodide–1,1,2,2‐tetraiodoethene (2/3), 2C5H12N4S2+·4I−·3C2I4, 11. When utilizing the common halogen‐bond‐donor molecules 1,2‐, 1,3‐, and 1,4‐diiodotetrafluorobenzene, as well as 1,3,5‐trifluoro‐2,4,6‐triiodobenzene, bifurcated I…S…I interactions were observed, resulting in the formation of isolated rings, chains, and sheets. Tetraiodoethylene (TIE) provided I…S…I cocrystals as well, but further yielded a sulfonium‐containing product through the reaction of the S atom with TIE. This particular sulfonium motif is the first of its kind to be structurally characterized, and is stabilized in the solid state through a three‐dimensional I…I halogen‐bonding network. Thiourea reacted with acetone in the presence of TIE to provide two novel heterocyclic products, again stabilized in the solid state through I…I halogen bonding. The combination of thiourea or 1,3‐dimethylthiourea with the common halogen‐bond donors 1,2‐, 1,3‐, or 1,4‐diiodotetrafluorobenzene, 1,3,5‐trifluoro‐2,4,6‐triiodobenzene, and tetraiodoethylene provided several new halogen‐bonding cocrystals, as well as three novel reaction products involving the I2‐mediated oxidative formation of new C—S and C—N bonds.