1. Structurally characterised new twisted conformer for cyclen, controlled by metal ion complexation as seen in NiII and CuII complexes with halides and pseudohalides
- Author
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Jean-Pascal Sutter, Sakharam B. Tayade, Nattamai Bhuvanesh, Avinash S. Kumbhar, Abhineet Verma, Kateryna Bretosh, Joseph H. Reibenspies, Sailaja S. Sunkari, Department of Chemistry, Banaras Hindu University, Banaras Hindu University [Varanasi] (BHU), Texas A&M University [Galveston], Savitribai Phule Pune University [India], Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), DST, New Delhi, India (Project code : DST/YSS/2015/000993), Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,Metal ions in aqueous solution ,General Chemistry ,Dihedral angle ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Metal ,chemistry.chemical_compound ,Crystallography ,Cyclen ,visual_art ,visual_art.visual_art_medium ,Antiferromagnetism ,Molecule ,[CHIM.COOR]Chemical Sciences/Coordination chemistry ,General Materials Science ,Counterion ,Conformational isomerism - Abstract
International audience; Serendipitous self-assembly is a potential approach for achieving structurally versatile and unexpected solids with chosen metal–ligand combinations. Cyclen (1,4,7,10-tetraazacyclododecane) is an interesting flexible molecule, well explored for biological and material applications of its metal complexes. The dihedral angle (θ) between four nitrogen atoms of free cyclen is close to 0°. Still, it may vary upon complexation, allowing flexibility to adopt any two conformers, viz., (i) planar and (ii) twisted. The present work establishes the crucial role of metal ions in controlling the conformation adopted by cyclen through metal complexation. SCXRD studies of the complexes of cyclen with CuII and NiII with halides and pseudohalides as counterions reveal the existence of a planar conformation (θ = ∼0–3°) for cyclen in CuII systems and a highly twisted conformation (hitherto unreported) in NiII systems (θ = ∼52–55°). Further, SQUID magnetic studies for the dimeric [Ni1] complex reveal antiferromagnetic interactions between the two Ni centres.
- Published
- 2022