Evgeny Kremer - Academia.edu (original) (raw)
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A.N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences
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Papers by Evgeny Kremer
Developments in Petroleum Science, 2004
The oxidation of the rhenium vinylidene complex (g 5-C 5 H 5)(CO) 2 Re@C@C(H)Ph (2) with one equi... more The oxidation of the rhenium vinylidene complex (g 5-C 5 H 5)(CO) 2 Re@C@C(H)Ph (2) with one equivalent of AgBF 4 or (C 5 H 5) 2 FeBF 4 leads to the radical cation [(g 5-C 5 H 5)(CO) 2 Re@C@C(H)Ph] +Å (2 +Å) which undergoes dehydrodimerization only in the presence of triethylamine affording a mixture of the binuclear compounds (g 5-C 5 H 5)(CO) 2 Re@C@C(Ph)C(Ph)@C@Re (CO) 2 (g 5-C 5 H 5) (6, 55%) and [(g 5-C 5 H 5)(CO) 2 Re] 2 (l 2-C@C(Ph)CBCPh) (9, 22%). Both 6 and 9 are believed to arise via competitive C b-C b and C b-Re couplings of the intermediate r-phenylethynyl radicals [(g 5-C 5 H 5)(CO) 2 ReACBCPh] Å (5 Å). The former process directly yields 6 and the latter one produces 9 after reductive elimination and a 1,2-shift of the metal containing moiety. The enthalpies of C b-C b (À30.3 kcal/mol) and C b-Re (+0.3 kcal/mol) coupling processes estimated by DFT calculations are in accordance with the 6:9 ratio observed. The electrochemical behavior of 2, 6, 9 was studied by cyclic voltammetry. The X-ray structures of 2 and 9 are reported.
Developments in Petroleum Science, 2004
The oxidation of the rhenium vinylidene complex (g 5-C 5 H 5)(CO) 2 Re@C@C(H)Ph (2) with one equi... more The oxidation of the rhenium vinylidene complex (g 5-C 5 H 5)(CO) 2 Re@C@C(H)Ph (2) with one equivalent of AgBF 4 or (C 5 H 5) 2 FeBF 4 leads to the radical cation [(g 5-C 5 H 5)(CO) 2 Re@C@C(H)Ph] +Å (2 +Å) which undergoes dehydrodimerization only in the presence of triethylamine affording a mixture of the binuclear compounds (g 5-C 5 H 5)(CO) 2 Re@C@C(Ph)C(Ph)@C@Re (CO) 2 (g 5-C 5 H 5) (6, 55%) and [(g 5-C 5 H 5)(CO) 2 Re] 2 (l 2-C@C(Ph)CBCPh) (9, 22%). Both 6 and 9 are believed to arise via competitive C b-C b and C b-Re couplings of the intermediate r-phenylethynyl radicals [(g 5-C 5 H 5)(CO) 2 ReACBCPh] Å (5 Å). The former process directly yields 6 and the latter one produces 9 after reductive elimination and a 1,2-shift of the metal containing moiety. The enthalpies of C b-C b (À30.3 kcal/mol) and C b-Re (+0.3 kcal/mol) coupling processes estimated by DFT calculations are in accordance with the 6:9 ratio observed. The electrochemical behavior of 2, 6, 9 was studied by cyclic voltammetry. The X-ray structures of 2 and 9 are reported.