Cyclopropyllithium aggaregation and 199Hg NMR as a tool for exchange studies with organo‐mercury compounds†. (3rd August 2017)

• Record Type: Journal Article
• Authors: Fox, Thomas; Günther, Harald
• Other Names: Ihmels Heiko guestEditor.; Linker Torsten guestEditor.; Trofimov Aleksei guestEditor.
• Is Part Of: Journal of physical organic chemistry. Volume 30:Number 9(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-08-03
• Subjects: 13C NMR -- 6Li NMR -- 199Hg NMR -- aggregation -- cyclopropyllithium -- exchange -- NMR; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.3746
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract: Low‐temperature NMR studies revealed aggregate formation in cyclopropyllithium compounds. For C3 H5 Li (1), a static tetramer [ 1 J ( 6 Li, 13 C) = 6.5 Hz] was found in diethylether (DEE), while in tetrahydrofuran (THF) a dimer and a fluxional tetramer [ 1 J ( 6 Li, 13 C) = 9.3 and 4.7 Hz, respectively] were detected. Trans‐ 2, 3‐dimethyl‐1 (2) yielded in DEE/THF (1:1) diastereomeric dimers [ 1 J ( 6 Li, 13 C) = 9.3 Hz] and 2, 2, 3, 3‐tetramethyl‐1 (3) formed dimers in DEE and DEE/THF [ 1 J ( 6 Li, 13 C) = 10.0 and 9.6 Hz, respectively]. For bis‐( trans ‐2, 3‐dimethylcyclopropyl)‐mercury (7), ligand exchange could be detected by the isotopic fingerprint method with 199 Hg NMR at room temperature. 199 Hg NMR in connection with specific deuteration may thus be used for ligand exchange studies in the field of organomercury compounds. Abstract : NMR‐spectroscopy was used to study the aggregation behavior of cyclopropyllithium compounds. For the parent system1 a static tetramer was found in diethyl‐ether (DEE) and a dimer and a fluxional tetramer in tetrahydrofuran (THF). trans ‐2, 3‐Dimethyl‐1 (2 ) and 2, 2, 3, 3‐tetramethyl‐1 form only dimers in DEE/THF (1:1), those of2 as two diastereomers, while ligand exchange in (2 )2 ‐mercury was detected with 199 Hg NMR.