228099-08-9Relevant articles and documents
Palladacycles of sulfated and selenated Schiff bases of ferrocene-carboxaldehyde as catalysts for O-arylation and Suzuki-Miyaura coupling
Sharma, Alpesh K.,Joshi, Hemant,Bhaskar, Renu,Kumar, Satyendra,Singh, Ajai K.
, p. 2485 - 2496 (2017)
Schiff base ligands (L1: sulfated and L2: selenated) having a ferrocene core synthesized by reacting ferrocene-carboxaldehyde with 2-(phenylthio/seleno)ethylamine on treatment with Na2PdCl4 in the presence of NaOAc give cyclopalladated complexes [Pd(L1/L2-H)Cl] (1/2). Complex 1 of a sulfated Schiff base L1, on reacting with one equivalent of triphenylphosphine gives complex [Pd(L1-H)PPh3Cl] (3), formed due to cleavage of a Pd-S bond. With 2 such a reaction does not occur, as a Pd-Se bond being stronger than that of its sulfur analogue does not get cleaved. L1, L2 and their complexes 1-3 were authenticated with HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectroscopy. The single crystal structures of 1-3 were determined with X-ray diffraction. Palladium in all three complexes has nearly a square planar geometry. The Pd-S, Pd-Se and Pd-P bond distances are 2.4249(12), 2.5058(14) and 2.2445(17) ? respectively. The catalytic activity of complexes 1-3 was explored for O-arylation of phenol and Suzuki-Miyaura coupling (SMC) of phenylboronic acid with aryl bromides and chlorides. The optimum reaction time for SMC of ArBr is 3 h whereas for ArCl it is 6 h. The TON values of O-arylation catalyzed with complexes 1-3 are up to ～170 (TOF, 28 h?1) and SMC ～9300 (TOF, 3100 h?1) for the reaction time of the order of 3 and 6 h respectively. The catalytic process is somewhat more efficient with 2 (Pd bonded with a selenoether group), than 3, followed by 1.
Synthesis, X-ray structural determination and Moessbauer characterization of Schiff bases bearing ferrocene groups, their reduced analogues and related complexes
Bullita,Casellato,Ossola,Tomasin,Vigato,Russo
, p. 117 - 133 (1999)
[1+1], [1+2], [2+1] or [3+1] acyclic and [1+1] or [2+2] cyclic Schiff bases (LALS), containing ferrocene moieties, have been prepared by reaction of formyl- or 1,1′-diformylferrocene and the appropriate amines. Formyl- and 1,1-diformylferrocene form respectively the acyclic [2+1] LW and [2+2]n LZ compounds by reaction with 1,4-diaminomethylbenzene. Similar compounds (LTLV) have been obtained by condensation of aminomethylferrocene and 2,6-diformylpyridine, 2,6-diformyl-4-chlorophenol and 3-methoxy-2-hydroxybenzaldehyde. By reduction of these compounds with NaBH4 the corresponding ferrocene-amine derivatives (L′) have been synthesized. All these compounds have been characterized by physico-chemical measurements (IR, NMR, Moessbauer spectroscopy and FAB mass spectrometry) and LH, derived by the condensation of ferrocene-aldehyde and 1,5-diamino-3-oxa-pentane, also by an X-ray structural determination. The X-ray analysis of crystals of LH, grown from a diethyl ether solution, shows that two independent molecules are present in the asymmetric unit; these two molecules are chemically equivalent with the ferrocenyl groups in the eclipsed form. The coordination ability of these compounds towards d metal ions as copper(II), nickel(II), platinum(II) and rhodium(III) was investigated; while the Schiff bases (L) may suffer hydrolysis, their reduced analogues (L′) form stable, well-defined complexes of the type M(L′)(Cl)n (n=2, 3). The Moessbauer spectra of the prepared compounds show signals with δ at 0.44 and ΔEQ 2.30 mm s-1 for the Schiff bases LALS and 0.52 and 2.40 mm s-1 for the reduced analogues and hence may be diagnostic of the presence of Fe-CH=N- or Fe-CH2-NH- groups. The signals with δ at 0.51-0.55 and ΔEQ at 2.34-2.38 mm s-1 for the Schiff bases LTLV, having Fe-CH2-N=CH groups, resemble those of the reduced analogues.
