178327-97-4Relevant academic research and scientific papers
Stopped-flow mechanistic study of bromide substitution by an organonitrile at an iron(II) phosphinic centre; a π-electron driven process
Martins, Luísa M.D.R.S.,Pombeiro, Armando J.L.,Henderson, Richard A.
, p. 311 - 315 (1996)
The kinetics of the displacement reactions of the bromide ligands of trans-[FeBr2(depe)2] (depe=Et2PCH2CH2PEt2) by the organonitrile N≡CCH2C6H4OMe-4, in tetrahydrofuran (either in the absence or in the presence of added Br-), to give the corresponding mono- and dinitrile complexes trans-[FeBr(NCCH2C6H4OMe-4)(depe) 2]+ and trans-[Fe(NCCH2C6H4OMe-4) 2(depe)2]2+, have been investigated by stopped-flow spectrophotometry. The substitution reaction occurs by a mechanism involving rate-limiting dissociation of bromo ligands to form the unsaturated intermediates [FeBr(depe)2]+ (k1=1.52±0.02 s-1) and [Fe(NCR)(depe)2]2+ (k3=0.063±0.008 s-1) which add the nitrile ligand to form those nitrile complexes. The competition between the nitrile and Br- for such metal centres has also been investigated and a stronger inhibiting effect of added Br- is observed for the substitution of the second bromo ligand relative to the first one. The kinetic data are rationalized in terms of π-electronic effects of these unsaturated metal centres and of the bromide and nitrile ligands.
Syntheses, properties and Moessbauer studies of mono- and di-nitrile phosphine complexes of iron(II). Crystal structures of trans-[Fe(NCR)2(Et2PCH2CH2PEt 2)2][BF4]2 (R = Me or CH2C6H4OMe-4)
Martins, Luisa M. D. R. S.,Duarte, M. Teresa,Galvao, Adelino M.,Resende, Catarina,Pombeiro, Armando J. L.,Henderson, Richard A.,Evans, David J.
, p. 3311 - 3317 (2007/10/03)
Complexes trans-[FeL(NCR)(depe)2]Yn (R = Me, Et, CH2C6H4OMe-4, C6H4OMe-4, C6H4Me-4, Ph, C6H4F-4 or C6H4NO2-4; depe = Et2PCH2CH2PEt2; Y = BF4 or BPh4; L = Br, n = 1 1; L = NCR, n = 22) have been prepared by treatment of trans-[FeBr2(depe)2] (in MeOH and in the presence of [NBu4][BF4] or Na[BPh4]) with a stoichiometric or a twofold molar amount of the appropriate organonitrile. Electronic, NMR and Moessbauer spectral as well as FAB mass spectrometric data are reported. Moessbauer partial isomer shift (p.i.s.) and partial quadrupole splitting (p.q.s.) parameters have been estimated for the nitrile ligands and rationalised, with the overall i.s. and q.s., in terms of π- and σ-electronic effects. The FAB MS fragmentation patterns are also proposed, and the crystal structures of 2 (R = Me or CH2C6H4OMe-4, Y = BF4) have been determined.
