(η5-cyclopentadienyl)Fe(CO)2-complex of maleimide anion: An organometallic carbonyl probe for biomolecules containing HS groups

Diels-Alder reaction with cyclopentadiene and electronic structures of (η5-cyclopentadienyl)M(CO)x(η1-N-maleimidato) (M=Fe, Mo, W, x=2 or 3)

“…Complexes 1a-c were synthesized as previously described [10][11]. Cyclopentadiene was obtained by cracking of the dimer (Sigma-Aldrich) directly before use.…”

“…These applications prompted us to look at the Diels-Alder reactivity of metallo-carbonyl maleimides 1a-c [10,11] with the purpose of using this reaction for the introduction of the IR-detectable or containing heavy metals [12,13] probes into diene-containing biomolecule conjugates. We have earlier studied the reaction of 1a-c with thiol, amino and imidazole groups of biomolecules [10,11,[14][15][16] and now we became interested in extension of the applicability of these complexes for biomolecules bearing attached diene moieties.…”

Cysteine‐Specific, Covalent Anchoring of Transition Organometallic Complexes to the Protein Papain from Carica papaya

“…We have also contributed to this area with three other metallocarbonyl maleimides, 4, [38] 5 a and 5 b. [39] Their ability to label the cysteine-containing tripeptide glutathione (GSH) and BSA enriched with thiol groups by S-alkylation of the maleimide double bond, was assessed.…”

The phospha-Michael addition of dimethyl- and diphenylphosphites to the η1-N-maleimidato ligand: Inhibition of serine hydrolases by half-sandwich metallocarbonyl azaphosphonates

“…Complexes 1a-c were synthesized according to literature procedures [4,5]. 1,8-diazabicyclo-(5,4,0)undec-7-ene (DBU) was purchased from Aldrich.…”

“…We have been interested for a long time in the chemistry of the (g 5 -C 5 H 5 )M(CO) x (g 1 -N-maleimidato) complex 1a [4] and, more recently, in that of its molybdenum and tungsten analogs 1b and 1c [5]. The ethylenic bond of the maleimidato ligand in these complexes is readily attacked by nucleophiles such as thiols, amines or imidazoles.…”