SYNTHETIC AND STRUCTURAL STUDIES ON SOME 1,3-DISELENA-FERROCENOPHANES OF CARBON, SILICON AND TIN. CRYSTAL AND MOLECULAR STRUCTURE OF BIS(FERROCENE-1,1'-DISELENATO)TIN(IV) AT 163 K

Article abstract of DOI:10.1016/S0022-328X(00)87428-8

A series of 1,3-diselena-<3>ferrocenophanes of general formula Fe(C5H4Se)2Y, (Y=CH2, C(C6H5)2, Si(CH3)2, Si(C6H5)CH3, Sn(CH3)2 or Sn(C6H5)2) and a spiro compound 2Sn have been prepared by reaction of ferrocene-1,1'-diselenol and halide complexes of the Group IV elements.Spectroscopic properties of the compounds are reported.In solution these compounds are fluxional by a bridge-reversal process.The crystal structure of bis(ferrocene-1,1'-diselenato)tin(IV) has been determined at 163 K.At that temperature crystals have space group Pbcn with a 7.515(3), b 11.159(5) and c 24.308(10) Angstroem.Least-squares refinement gave R=0.040 for 2357 unique reflections whose intensities were measured by counter diffractometry.The molecules have two-fold crystallographic symmetry (Z=4) with the axis passing through the Sn atom.The Sn-Se bond lengths are 2.516(1) and 2.539(1) Angstroem, and the Se-Sn-Se valence angles show considerable variation, that in the ferrocenophane moiety being 108.6(1), and the others 104.5(2), 108.5(1), and 117.4(2) deg.The Se-C bond lengths are 1.901(4) and 1.903(4) Angstroem, with C-Se-Sn angles of 98.6(1) and 99.7(1) deg.The cyclopentadienyl rings are in an eclipsed conformation with a mean twist angle of 5.7 deg, and the Se atoms are displaced from the ring planes by 0.24 and 0.27 Angstroem yielding a non-bonded Se...Se separation of 4.00 Angstroem in the ferrocenophane moiety.