10.1021/acs.organomet.8b00387.s002
Zhihui Zhang
Zhihui
Zhang
Xuejun Feng
Xuejun
Feng
Qun Chen
Qun
Chen
Mingyang He
Mingyang
He
Yaoming Xie
Yaoming
Xie
R. Bruce King
R. Bruce
King
Energetics of Variable Hapticity of Carbocyclic Rings
in Cyclopentadienylmetal Carbonyl Systems of the Second Row Transition
Metals C<sub>5</sub>H<sub>5</sub>M(CO)<sub><i>n</i></sub>C<sub><i>m</i></sub>H<sub><i>m</i></sub> (M =
Ru, Tc, Mo, Nb) Including Mechanistic Studies of Carbonyl Dissociation
American Chemical Society
2018
Cyclopentadienylmetal Carbonyl Systems
derivative
C 8 H 8 ring
16- electron configuration
C 8 H 8
uncomplexed
CpM
energy barrier
Carbonyl Dissociation Decarbonylation
CpNb
decarbonylation step proceeds
C n H n ring
energy transition state
monocarbonyl
C n H n
2018-07-23 17:49:41
Dataset
https://acs.figshare.com/articles/dataset/Energetics_of_Variable_Hapticity_of_Carbocyclic_Rings_in_Cyclopentadienylmetal_Carbonyl_Systems_of_the_Second_Row_Transition_Metals_C_sub_5_sub_H_sub_5_sub_M_CO_sub_i_n_i_sub_C_sub_i_m_i_sub_H_sub_i_m_i_sub_M_Ru_Tc_Mo_Nb_Including_Mechanistic_Studies_of_C/6852368
Decarbonylation of the experimentally
known CpRu(CO)<sub>2</sub>(η<sup>1</sup>-C<sub>5</sub>H<sub>5</sub>), CpMo(CO)<sub>2</sub>(η<sup>3</sup>-C<sub>7</sub>H<sub>7</sub>), and CpNb(CO)<sub>2</sub>(η<sup>4</sup>-C<sub>8</sub>H<sub>8</sub>) (Cp = η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>), each with uncomplexed 1,3-butadiene
units in the C<sub><i>n</i></sub>H<sub><i>n</i></sub> ring, as well as the related CpTc(CO)<sub>2</sub>(η<sup>2</sup>-C<sub>6</sub>H<sub>6</sub>), to give the corresponding carbonyl-free
derivatives CpM(η<sup><i>n</i></sup>-C<sub><i>n</i></sub>H<sub><i>n</i></sub>) derivatives has been
studied by density functional theory. For ruthenium, technetium, and
molybdenum the coordinated C<sub><i>n</i></sub>H<sub><i>n</i></sub> ring of the intermediate monocarbonyl CpM(CO)(η<sup><i>n</i>–2</sup>-C<sub><i>n</i></sub>H<sub><i>n</i></sub>) contains an uncomplexed CC double
bond and each decarbonylation step proceeds with a significant energy
barrier represented by a higher energy transition state. However,
decarbonylation of CpNb(CO)<sub>2</sub>(η<sup>4</sup>-C<sub>8</sub>H<sub>8</sub>) to the monocarbonyl proceeds without an energy
barrier, preserving the tetrahapto coordination of the C<sub>8</sub>H<sub>8</sub> ring to give CpNb(CO)(η<sup>4</sup>-C<sub>8</sub>H<sub>8</sub>) in which the niobium atom has only a 16-electron configuration.
All of the monocarbonyl derivatives CpM(CO)(C<sub><i>n</i></sub>H<sub><i>n</i></sub>) are predicted to be strongly
energetically disfavored with respect to disproportionation to give
CpM(CO)<sub>2</sub>(C<sub><i>n</i></sub>H<sub><i>n</i></sub>) + CpM(C<sub><i>n</i></sub>H<sub><i>n</i></sub>). This allows us to understand the failure to date to synthesize
any of the monocarbonyl derivatives.