Synthesis and characterization of difunctionalized derivatives of the cyclobutadiene linked dimeric cobalt sandwich compound [(η5-Cp)Co(η4-C4Ph3)]2

Multiferrocenyl Cobalt‐Based Sandwich Compounds

“…In compound 3a , this vibration is found at 2195 cm –1 as very weak absorption, whereas in 4b it could not be detected. Similar results were observed for compounds Co[η 5 ‐C 5 H 4 C(O)OMe][η 4 ‐C 4 Ph 3 (C≡CPh)] [ν(C≡C) 2186 cm –1 ] and [Co(η 5 ‐C 5 H 4 C(O)OMe)(η 4 ‐C 4 Ph 2 (C≡CPh)) 2 ] [ν(C≡C) 2190 cm –1 ] …”

“…However, only a few crystals of 4a could be isolated at ambient temperature from a n ‐hexane/dichloromethane mixture (ratio 3:1, v/v) containing isomers 4a , b . Compounds similar to 4a , b together with a proposed reaction mechanism have recently been published by Mandapati et al…”

“…1,4‐Diferrocenylbutadiyne offers the possibility to build complex polymetallic structures containing several ferrocenyl groups at a discrete molecule by applying the known cyclization protocol . In this article, we present a “one‐pot” synthetic methodology affording a range of multiferrocenyl‐crowded cyclodimerized and cyclotrimerized species obtained from the reaction of FcC≡C–C≡CFc with Co(η 5 ‐C 5 H 5 )(CO) 2 .…”

Synthesis, Spectral, and Structural Studies of Porphyrins Having Sterically Hindered [η5-CpCo(η4-C4Ph4)] Cobalt Sandwich Units at the Meso Positions

“…Compared to ferrocene, the cyclopentadienyl ring of this compound has been found to be very poorly reactive under standard metallocene derivatization procedures . However, we as well as others have been developing alternate methods to prepare novel derivatives of this highly stable and easy to handle cobalt sandwich compound. − The basal bulkiness of η 5 -CpCo­(η 4 -C 4 Ph 4 ) has resulted in the development of excellent chiral organometallic catalysts, while its electron donor capability has shown potential for realizing organic luminescent materials and photovoltaic devices . In this paper we report the synthesis and characterization of the first examples of η 5 -CpCo­(η 4 -C 4 Ph 4 ) derived porphyrins by a base-catalyzed synthesis using the hitherto unknown dipyrromethane derivative of η 5 -CpCo­(η 4 -C 4 Ph 4 ).…”

Chemistry of the highly stable hindered cobalt sandwich compound (η5-Cp)Co(η4-C4Ph4) and its derivatives

“…An unsymmetrical cyclobutadiene linked dimer having methylester group on one Cp ring and acetyl group on the other Cp ring (compound 399) has also been prepared by starting with a Cb alkynyl derived cobalt sandwich compound 398 (Scheme 83) [185].Scheme 83. Synthesis of unsymmetrical cyclobutadiene linked dimer[185] The chemistry of the ester units on the cyclobutadiene linked sandwich compound 391 has been explored further by reducing them to the corresponding diol 400 using LiAlH 4 and further reactions of the same leading to diazide 401, diamine 402, bis triazole 403 and bis acetoxy 404 derivatives using standard reaction conditions as shown in Scheme 84[185].Scheme 84.Reactions of dimeric diester 391[185] …”