Cyclopropene als Komplexliganden: Vinylcarben‐ und Vinylketen‐Komplexe des Eisens und Cobalts: präparative und röntgenographische Ergebnisse

Abstract

Result8As previously shown, it is possible to interconvert under very mild conditions the vin ylketene-and vinylcarbene-Fe(CO), complexes 2 and 3 obtained by the reaction of FedCOk with the dimer 1 of diphenylcyclopropene. They thus represent a model system of the carbonylation reaction of a carbene complex. Investigating further the reactivity of complex 3 we studied l;eactions with different phosphanes (PR,, PR,R) and phosphites P(0Rh. Normally displacement of CO and formation of metal-substituted ketene complexes OcCuT. In the case of R = Ph another carbeneketene pair 4a/5a was found to react with CO reversibly, similar to 2 and 3. 3 adds also CH2 to form a (b~tadiene)Fe(CO)~ complex (7). (C5H& Co(CO), also causes ring opening in 1 to yield a vinylketene compound 9 with the CpCo(CO), moiety. The crystal structures of 9 and of three Fe complexes (44% 5a) have been determined. Praparative Ergebnisse Eisen-VerbindungenIn Fortfuhrung dieser Arbeiten erfolgten weitere Untersuchungen am Carben-Komplex 3 zunachst mit dem Ziel, dessen Reaktionsfahigkeit gegeniiber Phosphanen und Phosphiten (L) zu priifen. Schema 1 gibt einen Oberblick uber die durchgefuhrten Reaktionen und die dabei erhaltenen Ergebnisse. In allen Fallen erfolgt Addition des Liganden L an das Metall unter Verdrangung einer CO-Gruppe, welche in die Chem.

Reactions of a Chelated Cyclopentadienylcobalt(I) Complex with 3,3-Disubstituted Cyclopropenes: Formation of Isoprene, Vinylcarbene, and 1-Phosphadiene Ligands at the Metal

“…Recently, we reported the formation of Cp # Co vinylidene complexes. , Reactions with tert -butylphosphaethyne resulted in complete cleavage of the P⋮C bond with formation of a phosphido cluster, whose phosphido ligand could be oxidized to a PO or PS ligand . Cyclopropenes form complexes with transition metals or react with transition metal complexes to form oligomers − or vinylcarbene complexes. , Because only a few vinylcarbene complexes of cobalt are known , and in light of the role of vinylcarbene complexes in catalysis, we undertook the preparation of such species by treatment of Cp # Co complexes such as 1 or 2 with cyclopropenes.…”

Synthesis of tricarbonyl(vinylallene)iron(0) complexes from tricarbonyl(vinylketene)iron(0) complexes and their oxidation to 5,5-disubstituted furan-2(5H)-ones

“…Of note is the 0.65 ppm difference in the resonances due to the hydrogen attached to C ( l ) (6 5.82 in 9amai and 6 6.47 in gamin). The I3C NMR spectrum of 9amaj contained resonances at (5 110.2, 188.1, 84.5, 89.6 and 62.0 assigned to C(l)-C (5) respectively and resonances due to the Ph, Me and C0,Me substituents (Table 4). The EI mass spectrum of 9amaj contained a small M + peak (4.6";,) and a fragmentation pattern corresponding t o stepwise loss of the three CEO ligands and the iron atom (Table 5).…”

Synthesis of Bis(trityl)iron(II) and Formation of the Iron(0)-Stabilized o,o-Isomer of Gomberg’s Dimer

“…The C–C distances within the exocyclic alkene groups (C1–C2 = 1.343(8), C20–C21 = 1.363(7) Å) are similar to those observed for 1 . Finally, the average Fe–P distance (2.13 Å) is similar to those seen in other Fe(0) phosphite complexes. − Complex 3 was also characterized by X-ray crystallography (Figure S1), confirming its formulation as a trimetallic complex. Complete crystallographic details can be found in the Supporting Information.…”