Solvent-free Substitution Reactions of Solid Phosphines with (η⁵-RC₅H₄)Fe(CO)₂I (R = H, Me) Complexes

Abstract

Dedicated to Prof. Helgard G. Raubenheimer on the occasion of his 65 th birthdayfriend and colleague over many decadesReactions of (η 5 -RC 5 H 4 )Fe(CO) 2 I (R = H, Me) complexes with phosphine ligands PR 3 (R = Ph, m-Tol, p-C 6 H 4 OMe, p-C 6 H 4 Cl, p-C 6 H 4 F) have been performed under solvent-free conditions in the melt phase and generally yielded the ionic products [(η 5 -RC 5 H 4 )Fe(CO) 2 PR 3 ]I rather than the CO substituted products (η 5 -RC 5 H 4 )Fe(CO)(PR 3 )I. The complexes have been characterised by IR, NMR and MS techniques. By contrast, the same reactions studied in benzene solution have yielded mainly the CO substitution products. Factors that affect the solvent-free reaction include variation in R and R , reaction temperature and the addition of [CpFe(CO) 2 ] 2 as a catalyst. The mechanism of the reaction for the formation of the ionic complex is proposed to go via a 19 electron intermediate. This is in contrast to the reaction in bezene that occurs via a 17 electron intermediate, clearly indicating the role of the melt phase in the reaction.

Synthesis and Skeletal Transformations of Trinuclear Palladium and Nickel Phosphido Complexes

“…Another indication that phosphanes and phosphido systems behave similarly is provided by [CpFe(CO) 2 PPh 2 ],34 a terminal phosphido group with δ ( 31 P) = 8.3 ppm. It could also be considered a metallophosphane35 that is deshielded compared to PPh 3 with δ ( 31 P) = –5 ppm; both change their 31 P chemical shifts upon coordination to [CpFe(CO) 2 ] + by 54–67 ppm: [CpFe(CO) 2 –PPh 2 –Fe(CO) 2 Cp] + δ ( 31 P) = 61.8 ppm,36 [CpFe(CO) 2 (PPh 3 )]I δ ( 31 P) = 61.8 ppm 37. In conclusion, the 31 P chemical shifts of 4 and the other complexes in the present study appear to be reasonable for a phosphido bridging group not involved in a small ring nor spanning M–M interactions.…”

Migration Insertion Polymerization (MIP) of Cyclopentadienyldicarbonyldiphenylphosphinopropyliron (FpP): A New Concept for Main Chain Metal-Containing Polymers (MCPs)

“…Since MIR can also occur in solid state, , bulk polymerization of FpP was performed at 70 °C to suppress intramolecular cyclic reactions. During the polymerization, the viscosity of the system gradually increased until glass-like solid material was produced with the stir bar frozen inside the product.…”

Substitution reactions of Fe and Ru complexes with liquid phosphite ligands in the absence of solvents

“…In contrast, the solid-solid solvent-free reactions between CpFe(CO) 2 I and phosphine ligands showed improved rates and conversions when compared to the products obtained from the same reaction in benzene as a solvent [12].…”

“…In contrast, in refluxing benzene, the catalyzed reaction between MeCpFe(CO) 2 I with P(OMe) 3 easily afforded the product MeCpFe(CO)[P(OMe) 3 ]I [17]. Similar solvent-free (melt) studies with solid phosphines were observed to be accelerated when an electron donating substituent is attached to the Cp ligand, although the product obtained was the salt product, [MeCpFe(CO) 2 [P(OR) 3 ]I [12].…”