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Halogen Bonding between an Isoindoline Nitroxide and 1,4‐Diiodotetrafluorobenzene: New Tools and Tectons for Self‐Assembling Organic Spin Systems
Author(s) -
Hanson Graeme R.,
Jensen Paul,
McMurtrie John,
Rintoul Llew,
Micallef Aaron S.
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801920
Subject(s) - isoindoline , nitroxide mediated radical polymerization , chemistry , halogen bond , supramolecular chemistry , intermolecular force , halogen , photochemistry , electron paramagnetic resonance , crystallography , molecule , hydrogen bond , crystal structure , organic chemistry , nuclear magnetic resonance , alkyl , polymer , radical polymerization , copolymer , physics
Radical assembly : Halogen bonding has been observed for the first time between an isoindoline nitroxide and an iodoperfluorocarbon (see figure), which cocrystallize to form a discrete 2:1 supramolecular compound in which NO . ⋅⋅⋅I halogen bonding is the dominant intermolecular interaction. This illustrates the potential use of halogen bonding and isoindoline nitroxide tectons for the assembly of organic spin systems.The isoindoline nitroxide 1,1,3,3‐tetramethylisoindolin‐2‐yloxyl (TMIO) and 1,4‐diiodotetrafluorobenzene readily form a discrete 2:1 complex that shows evidence of relatively strong NO . ⋅⋅⋅I halogen bonding. This interaction was characterized in the solid state by single‐crystal X‐ray analysis, thermal analysis, and vibrational spectroscopy (IR and Raman), backed by density functional theory calculations. EPR spectroscopy performed on a solution of TMIO in pentafluoroiodobenzene, a halogen‐bonding donor, indicates that halogen bonding induces an increase in electron density at the nitroxide nitrogen nucleus and an increase in the nitroxide rotational correlation time. Our findings demonstrate the potential of utilizing halogen‐bonding interactions to promote the self‐assembly of new isoindoline nitroxide tectons for the preparation of organic spin systems.