Bis(aryldiazene) Derivatives of Iron(II): Preparation, Characterization, and Properties of the First Complexes Containing Two Diazene Ligands Bonded to the Same Central Metal. The X-ray Crystal Structures of Hexacoordinate 4>(1+) and Pentacoordinate...

Article abstract of DOI:10.1021/ja00281a029

The complexes BPh4 (1) and (BPh4)2 (2) a), 4-CH3OC6H4 (b), 4-FC6H4 (c)> were prepared by reacting hydride FeH2L4 with aryldiazonium cations in CH2Cl2 at -80 deg C.Their characterization by (1)H and (31)P<(1)H> NMR (with (15)N isotopic substitution) is reported.The reaction of bis(diazene) 2 with triethylamine was investigated and led to the synthesis of new pentacoordinate (1+) (3) a), 4-CH3OC6H4 (b), 4-FC6H4 (c)> aryldiazenido complexes, which were isolated and characterized by infrared and (31)P<(1)H> NMR spectroscopy.The structures of compounds 1a and 3a were determined crystallographically.The compounds crystallize in the space group P2₁/n (a = 21.271 (8) Angstroem, b = 15.727 (4) Angstroem, c = 20.580 (7) Angstroem, β = 112.77 (3) deg, and Z = 4) and P<*> (a = 14.834 (8) Angstroem, b = 18.942 (10) Angstroem, c = 11.738 (6) Angstroem, α = 100.59 (4) deg, β = 90.36 (5) deg, γ = 95.52 (4) deg, and Z = 2), respectively.Both structures were solved by heavy-atom techniques and were refined by least-squares calculations to R = 0.0839 and 0.0779, respectively.In 1a the iron cation is six-coordinate with the diazene and the hydride ligand in mutually cis position.The structure of 3a consists of discrete cations and anions.The cation is five-coordinate with coordination geometry close to trigonal bipyramidal with an equatorial single-bent aryldiazenido group.Significant angles and distances are the following: Fe-N(1) = 1.672 (9) Angstroem, N(1)-N(2) = 1.224 (13) Angstroem; Fe-N(1)-N(2) = 166.6 (9) deg, N(1)-N(2)-C(p-tolyl) = 120.3 (10) deg.