Coupling of CpCr(CO)3 and heterocyclic dithiadiazolyl radicals: synthetic, X-ray diffraction, dynamic NMR, EPR, CV and DFT studies

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Lau, Hiu F.
Ang, Chwee Y.
Ng, Victor W. L.
Kuan, Seah L.
Goh, Lai Y.
Borisov, Alexey S.
Hazendonk, Paul
Roemmele, Tracey L.
Boeré, René T.
Webster, Richard D.
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ACS Publications
The reaction of 1,2,3,5-dithiadiazolyls, (4-R-C6H4CN2S2)2 (R = Me, 2a; Cl, 2b; OMe, 2c; and CF3, 2d) and (3-NC-5-tBu-C6H3CN2S2)2 (2e) with (CpCr(CO)3]2 (Cp = η5-C5H5) (1) at ambient temperature, yielded respectively the complexes CpCr(CO)2(η2-S2N2CC6H4R) (R = 4-Me, 3a; 4Cl, 3b; 4-OMe, 3c; and 4-CF3, 3d) and CpCr(CO)2(η2-S2N2CC6H3-3-(CN)-5-(tBu)) (3e) in 35 – 72 % yields. The complexes 3c and 3d were also synthesized via a salt metathesis method from the reaction of NaCpCr(CO)3 (1B) and the 1,2,3,5-dithiadiazolium chlorides, 4-R-C6H4CN2S2Cl (R = OMe, 8c; CF3, 8d) with much lower yields of 6 and 20 %, respectively. The complexes were characterized spectroscopically, and also by single crystal X-ray diffraction analysis. Cyclic voltammetry experiments were conducted on 3a-e, EPR spectra were obtained of one-electron reduced forms of 3a-e, and variable temperature 1H NMR studies were carried out on complex 3d. Hybrid DFT calculations were performed on the model system [CpCr(CO)2S2N2CH] and comparisons are made with the reported CpCr(CO)2(π-allyl) complexes.
Sherpa Romeo white journal. This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher.
Dithiadiazolyl , Organometallic radical , C,N,S-heterocyclic radicals , Cyclopentadienyl chromium , π-complexes of C,N,S-heterocyclic rings , X-ray structural , CV , EPR , Computational studies
Lau, H. F., Ang, P. C.Y., Ng, V. W. L., Kuan, S. L., Goh, L. Y., Borisov, A. S., ... Webster, R. D. (2008). Coupling of CpCr(CO)3 and heterocyclic dithiadiazolyl radicals: Synthetic, X-ray diffraction, dynamic NMR, EPR, CV and DFT studies. Inorganic Chemistry, 47(2), 632.644. doi:10.1021/ic702128f