851576-90-4Relevant academic research and scientific papers
CpCo-stabilized cyclopentadienones from cyclobutadiene complexes: Experimental and theoretical investigations
Schaefer, Garsten,Werz, Daniel B.,Staeb, Tobias H.,Gleiter, Rolf,Rominger, Frank
, p. 2106 - 2113 (2008/10/09)
The reaction of 1,4,8,11-tetrathiacyclotetradeca-2,9-diyne (7) with C 5H4(CO2Me)Co(CO)2 (8) and C 5H4(SiMe3)Co(CO)2 (10) led to the tricyclic cyclopentadienone complexes 9 and 11. In both species the CO was inserted into a former triple bond. This observation led to the preparation of the tetrathiaalkyl- and tetrathiaaryl-substituted C5H 4(CO2Me)Co-capped cyclobutadiene complexes 23 and 27-30. When these compounds were heated under a pressurized CO atmosphere at 170 °C, the corresponding cyclopentadienone complexes 9, 15, and 31-33 were formed. Model calculations at the B3LYP level of theory on tetrasub-stituted (R = CH3, SH, (CH2)3, S-CH2-S) CpCo-capped cyclobutadiene complexes showed that the substitution, especially by SH and S-CH2-S, considerably lowered the energy of the assumed intermediate metallacycles 35 and 36, which opens the possibility of reaction.
