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Synthesis and Properties of [CoCp*(2,5‐PC 4 t Bu 2 H 2 )]: The First Monophosphacobaltocene
Author(s) -
Burney Claire,
Carmichael Duncan,
Forissier Kareen,
Green Jennifer C.,
Mathey François,
Ricard Louis
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200204421
Subject(s) - tetrahydrofuran , crystallography , chemistry , cyclopentadienyl complex , ligand (biochemistry) , crystal structure , atom (system on chip) , stereochemistry , catalysis , biochemistry , receptor , organic chemistry , solvent , computer science , embedded system
The reduction of the phosphacobaltocenium salt [CoCp*(2,5‐PC 4 t Bu 2 H 2 )] + [BPh 4 ] − ( 3 ; Cp*=pentamethylcyclopentadienyl) by magnesium in tetrahydrofuran (THF) furnishes the stable air‐sensitive phosphacobaltocene [CoCp*(2,5‐PC 4 t Bu 2 H 2 )] ( 4 ) in yields of up to 80 %. The crystal structure of 4 shows long CoC α and short C α C β bonds in the phospholyl ligand, consistent with a semi‐occupied molecular orbital (SOMO) having a″ symmetry. A combined Amsterdam density functional (ADF)/photoelectron spectroscopic study, which confirms this assignment, gives ionisation energies (IE) of 5.02 eV from the SOMO and 8.89 eV from the phosphorus “lone pair”. A comparison of cyclovoltammograms for 3 and the corresponding cyclopentadienyl complex [CoCp*(1,3‐C 5 t Bu 2 H 3 )] + [BPh 4 ] − ( 5 ) shows that replacing a CH group by an sp 2 phosphorus atom results in an anodic first reduction potential shift of 0.29 V.