Electronic structures and EPR spectra of carbonylbis(cyclopendienyl) vanadium(II) and carbonylbis(pentadienyl)vanadium(II)

Reactions of Ferrocenium Hexafluorophosphate with P−OR Nucleophiles Give Ring C−H Functionalization or Ring Replacement Products Depending on the Phosphorus Reagent

“…* is oriented perpendicular to the plane containing the centroids of Cp and CO ligands. [30] Our computations give similar shapes for these orbitals (Figure S26 and Figure S27). Thus, the SOMO of the latter complex is sterically accessible for the attack of a nucleophile, which makes the associative substitution mechanism possible.…”

Syntheses, Structures, and NMR Spectroscopy of Paramagnetic Open Vanadocenes and Open Chromocenes

“…Thus, Cp 2 V is a S = 3/2 compound with δ = 314.2 ppm and Δ ν 1/2 = 2.3 kHz at 298 K,23a while compound 9 has a S = 1/2 ground state,12c leading to smaller signal shifts (as far as detectable) and to different relaxation times. It has been shown that the unpaired electron of the parent open vanadocene occupies a d z 2 -type orbital . This situation seems to entail rather long electron relaxation times quite generally. , …”

Open-Shell Organometallics as a Bridge between Werner-Type and Low-Valent Organometallic Complexes. The Effect of the Spin State on the Stability, Reactivity, and Structure

“…Vanadocene ( XCI ) and a number of derivatives with substituted Cp rings, including the bis(indenyl) compound, have three unpaired electrons ,,, and relatively sharp, paramagnetically shifted resonances in the 1 H- and 13 C-NMR spectra. ,, However, the energy of the excited state doublet configuration must not be too far away. Indeed, the similar open metallocene derivative (Pdl‘) 2 V, the half-open Cp(Pdl # )V (Pdl # = 1,5-bis(trimethylsilyl)-2,4-pentadienyl), and (dmCh) 2 V show a doublet ground state configuration. ,− Theoretical calculations at the SCF-DV-Xα level reproduce the experimental ground states for Cp 2 V and Pdl 2 V . A spin change occurs for the facile addition of neutral 2-electron donors to Cp 2 V to afford spin doublet 17-electron Cp 2 VL adducts (e.g.…”

“…) 1,5-bis(trimethylsilyl)-2,4pentadienyl), and (dmCh) 2 V show a doublet ground state configuration. 336,[461][462][463][464] Theoretical calculations at the SCF-DV-XR level reproduce the experimental ground states for Cp 2 V and Pdl 2 V. 465 A spin change occurs for the facile addition of neutral 2-electron donors to Cp 2 V to afford spin doublet 17-electron Cp 2 -VL adducts (e.g. L ) CO, CS 2 , CH 2 O, bipy, or electron-deficient olefins and alkynes such as diethyl fumarate or maleate).…”