Halogen-Bond Mediated [2+2] Photodimerizations: À la Carte Access to Unsymmetrical Cyclobutanes in the Solid State

Molecules

Leonard R. MacGillivray¹  Jay Quentin¹  Eric W. Reinheimer² 

[1] Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA;Rigaku Americas Corporation, 9009 New Trails Drive, The Woodlands, TX 77381, USA;

关键词: cocrystal;    crystal engineering;    halogen bonding;    photodimerization;    cyclobutane;   

DOI  :  10.3390/molecules27031048

来源: DOAJ

【 摘 要 】

The ditopic halogen-bond (X-bond) donors 1,2-, 1,3-, and 1,4-diiodotetrafluorobenzene (1,2-, 1,3-, and 1,4-di-I-tFb, respectively) form binary cocrystals with the unsymmetrical ditopic X-bond acceptor trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene (2,4-bpe). The components of each cocrystal (1,2-di-I-tFb)·(2,4-bpe), (1,3-di-I-tFb)·(2,4-bpe), and (1,4-di-I-tFb)·(2,4-bpe) assemble via N···I X-bonds. For (1,2-di-I-tFb)·(2,4-bpe) and (1,3-di-I-tFb)·(2,4-bpe), the X-bond donor supports the C=C bonds of 2,4-bpe to undergo a topochemical [2+2] photodimerization in the solid state: UV-irradiation of each solid resulted in stereospecific, regiospecific, and quantitative photodimerization of 2,4-bpe to the corresponding head-to-tail (ht) or head-to-head (hh) cyclobutane photoproduct, respectively.

【 授权许可】

Unknown