The effect of substitution of a thioether donor by a phosphine donor in thiacrown complexes of iron

Abstract

Michael J. (2002) The effect of substitution of a thioether donor by a phosphine donor in thiacrown complexes of iron. AbstractElectrospray mass spectrometry and thermogravimetric analysis reveals that bis(1-phenyl-1phospha-4,7-dithiacyclononane)iron(II) is more susceptible to ethene loss than bis(1,4,7trithiacyclononane)iron(II). This is in accord with X-ray crystallographic studies, which show that the C-S bonds are longer in the former complex suggesting an increased population of the C-S   -acceptor orbitals.

Design and Synthesis of a Bombesin Peptide-Conjugated Tripodal Phosphino Dithioether Ligand Topology for the Stabilization of the fac-[M(CO)3]+ Core (M = 99 mTc or Re)

“…Indeed, several previous reports involving facially spanning 1,4,7-trithia cyclononane (9S 3 ) complexes [M(9S 3 ) 2 ] + (M = Tc, Re, Ru, Os) provide evidence for the susceptibility of these systems for ethene loss. 16 While the incorporation of a phosphine center within the macrocyclic framework (e.g., 9PS 2 ligands) improved the kinetic inertness of [Mo(9PS 2 )(CO) 3 ] + in comparison with [Mo(9S 3 )(CO) 3 ] + , the reverse has been found to be true in a comparative study of [Fe(9S 3 ) 2 ] 2+ and [Fe(9PS 2 ) 2 ] 2+ . 16 In this context, results from our current studies have demonstrated that the compact PS 2 ligand system possesses topology for facial tridentate coordination with Tc(CO) 3 + /Re(CO) 3 + cores, thereby producing five-membered [M(CO) 3 (PS 2 )] + (M = Tc/Re) compounds that are both kinetically robust and in vivo stable.…”

Cyclononanes: The extensive chemistry of fundamentally simple ligands

“…It was proposed that unbound benzyldivinylphosphine acted as a base to abstract a proton from the acidic NH 2 groups thus enabling attack of the liberated nitrogen lone pair at a coordinated benzyldivinylphosphine [289]. Complete conversion to the macrocyclic species was achieved after removal of the original reaction solvent, dissolution of the residues in THF and reaction with potassium tert- spectroscopy and elemental analysis [99], although the nickel(II) and iron(II) complexes were subsequently characterised with X-ray crystallography [304,305].…”

“…Crystal structure of 7-phenyl-1,4,7-dithiaphosphonane 7-sulfide[303] Iron(II) The structure of [Fe([9]aneP(Ph)S 2 ) 2 ](BF 4 ) 2 is pseudo octahedral with the phosphine donors trans(Figure 113)[304]. The Fe-S distances (2.2445(7) Å and 2.2516(7) Å) and the Fe-P distance of 2.2244(7) Å was significantly shorter than both the Fe-S distances and Cambridge Crystallographic Database average for iron-phosphine bonds (2.25 Å)[304].…”

“…Crystal structure of 7-phenyl-1,4,7-dithiaphosphonane 7-sulfide[303] Iron(II) The structure of [Fe([9]aneP(Ph)S 2 ) 2 ](BF 4 ) 2 is pseudo octahedral with the phosphine donors trans(Figure 113)[304]. The Fe-S distances (2.2445(7) Å and 2.2516(7) Å) and the Fe-P distance of 2.2244(7) Å was significantly shorter than both the Fe-S distances and Cambridge Crystallographic Database average for iron-phosphine bonds (2.25 Å)[304]. The authors concluded that in comparison to complexes such as the analogue [Fe([9]aneS 3 ) 2 ] 2+ , based on the mass spectrometry, thermogravimetric, and structural data, replacement of a thiaether by a phosphine weakens the remaining C-S bonds, the implication being that in the[9]aneP(Ph)S 2 complex the C-S σ* orbitals are accepting more electron density than the analogous[9]aneS 3 complex.…”

“…The authors concluded that in comparison to complexes such as the analogue [Fe([9]aneS 3 ) 2 ] 2+ , based on the mass spectrometry, thermogravimetric, and structural data, replacement of a thiaether by a phosphine weakens the remaining C-S bonds, the implication being that in the[9]aneP(Ph)S 2 complex the C-S σ* orbitals are accepting more electron density than the analogous[9]aneS 3 complex. Hence the C-S bonds are longer and weaker in [Fe([9]aneP(Ph) S 2 ) 2 ](BF 4 ) 2 compared with [Fe([9]aneS 3 ) 2 ] 2+ resulting, it was proposed, in more facile ethene loss[304].…”