Synthesis with structural and electronic characterization of homoleptic Fe(II)- and Fe(III)-fluorinated phenolate complexes.

Four Fe(III) compounds and one Fe(II) compound containing mononuclear, homoleptic, fluorinated phenolate anions of the form [Fe(OAr)(m)](n-) have been prepared in which Ar(F) = C(6)F(5) and Ar' = 3,5-C(6)(CF(3))(2)H(3): (Ph(4)P)(2)[Fe(OAr(F))(5)], 1, (Me(4)N)(2)[Fe(OAr(F))(5)], 2, {K(18-crown-6)}(2)[Fe(OAr(F))(5)], 3a, {K(18-crown-6)}(2)[Fe(OAr')(5)], 3b, and {K(18-crown-6)}(2)[Fe(OAr(F))(4)], 6. Two dinuclear Fe(III) compounds have also been prepared: {K(18-crown-6)}(2)[(OAr(F))(3)Fe(µ(2)-O)Fe(OAr(F))(3)], 4, and {K(18-crown-6)}(2)[(OAr(F))(3)Fe(µ(2)-OAr(F))(2)Fe(OAr(F))(3)], 5. These compounds have been characterized with UV-vis spectroscopy, elemental analysis, Evans method susceptibility, and X-ray crystallography. All-electron, geometry-optimized DFT calculations on four [Ti(IV)(OAr)(4)] and four [Fe(III)(OAr)(4)](-) species (Ar = 2,3,5,6-C(6)Me(4)H, C(6)H(5), 2,4,6-C(6)Cl(3)H(2), C(6)F(5)) with GGA-BP and hybrid B3LYP basis sets demonstrated that, under D(2d) symmetry, π donation from the O 2p orbitals is primarily into the d(xy) and d(z(2)) orbitals. The degree of donation is qualitatively consistent with expectations based on ligand Brønsted basicity and supports the contention that fluorinated phenolate ligands facilitate isolation of nonbridged homoleptic complexes due to their reduced π basicity at oxygen.

2-(2-Chloro-phen-yl)-3-(3,4-dimeth-oxy-phen-yl)quinoxaline.

The title compound, C(22)H(17)ClN(2)O(2), was synthesized by the condensation reaction between 1,2-phenyl-enediamine and 2-chloro-3',4'-dimeth-oxy-benzil in boiling acetic acid. The chloro-phenyl and dimeth-oxy-phenyl rings make dihedral angles of 78.45 (5) and 35.60 (4)°, respectively, with the quinoxaline unit.

Three-coordinate late transition metal fluorinated alkoxide complexes.

Homoleptic fluorinated alkoxide complexes have been prepared from KOC4F9, 1, via salt metathesis routes. One four-coordinate K{K(18C6)}[Co(OC4F9)4], 2, and four three-coordinate complexes: {K(18C6)}[Fe(OC4F9)3], 3, {K(18C6)}[Co(OC4F9)3], 4, {K(18C6)}[Cu(OC4F9)3], 5, and {K(18C6)}[Zn(OC4F9)3], 6, have been prepared and all except 5 have been characterized crystallographically. Compounds 3, 4, and 6 are very rare examples of monomeric, trigonal alkoxide complexes. All compounds have been characterized with UV-vis and IR spectroscopy, solution magnetic susceptibility, and elemental analysis. In solution, compound 2 exists in an equilibrium with 4 and 1, which has been probed with cyclic voltammetry, supporting energetically different Co2+/Co3+ potentials in the three-coordinate (E(p,a) = approximately 1.2 V vs Fc/Fc+) and four-coordinate (E(p,a) = approximately 0.9 V) geometries. The ligand field engendered by the perfluoro-t-butoxide ligand has been studied with DFT calculations on 4 and the hypothetical [Co(OC4H9)3]- as well as the previously reported [Co(mes)3]- and [Co{N(TMS)2}3]- showing significant -type interactions in the xy plane as well as above and below for the two alkoxide species.