459143-70-5Relevant academic research and scientific papers
Synthesis of oligometallic compounds from tripodiron(II) species using cyano bridging ligands - Electronic coupling of two metal termini through metal dicyano and diisocyano entities
Jacob, Volker,Huttner, Gottfried,Kaifer, Elisabeth,Kircher, Peter,Rutsch, Peter
, p. 2783 - 2795 (2001)
Organometallic monocyanometalates [M-CN]- (1-) [M = Cr(CO)5 1a-, Cr(η6-CF3C6H5)(CO)2 1b-, Mn(η5-CH3C5H4)(CO)2 1c-] produce tetrametallic (2-) and trimetallic (3) aggregates upon reaction with tripod and iron(II) salts [tripod = CH3C(CH2PPh2)3]. The tetranuclear compound [tripodFe{NC-M}3]- (2-) [M = Cr(CO)5] or the trinuclear species [tripodFe(CO){NC-M}2] (3) [M = Cr(CO)5 3a, Cr(η6-CF3C6H5)(CO)2 3b, Mn(η5-CH3C5H4)(CO)2 3c] can be selectively formed by following the appropriate reaction protocols. Organometallic dicyanometalates [NC-M′-CN]- (4-) [M′ = Mn(CO)4 4a-, CpFe(CO) 4b-, CpCo(CN) 4c-] react in a similar manner to give pentanuclear species [tripodFe{NC-M′-CN}3Fetripod]+ (5+). - In compounds 2- and 3, two easily oxidizable organometallic groups are linked through a tripodFe(NC)2 unit, while in 5+ two tripodiron(II) entities are linked through a less readily oxidizable M′(CN)2 unit. For both types of compound, at least two distinct reversible oxidations are observed by cyclic voltammetry. The potentials at which these oxidations occur are characteristic of the terminal groups in each case. The potentials of the two consecutive oxidation steps are separated by between 150 and 350 mV. The oxidation products of compounds 2-, 3, and 5+ can hence be classified as class III mixed-valence species with comproportionation constants KC of between 102 and 106. The extent of electronic coupling mediated by the M′(CN)2 or M′(NC)2 bridging entities is thus similar to that mediated by [RC(CN)2]- bridging ligands in otherwise analogous compounds, for which KC values of around 104 are observed. All the aforementioned compounds have been characterized by analytical and spectroscopic techniques, including cyclic voltammetry and UV/Vis spectroscopy. In addition, X-ray crystallographic data are reported for 2-, 3a, 3b, 3c, and 5a+. Wiley-VCH Verlag GmbH, 2001.
