Bis(pyrazol-1-yl)acetates as Tripodal Heteroscorpionate Ligands in Iron Chemistry:  Syntheses and Structures of Iron(II) and Iron(III) Complexes with bpza, bdmpza, and bdtbpza Ligands (original) (raw)

2003, Inorganic Chemistry

The molecular structure of the previously reported species "[Fe(bdtbpza)Cl]" has been revealed by X-ray structure determination to be a ferrous dimer [Fe(bdtbpza)Cl] 2 (2c) [bdtbpza) bis(3,5-di-tert-butylpyrazol-1-yl)acetate]. The syntheses of ferrous 2:1 complexes [Fe(bpza) 2 ] (3a) and [Fe(bdtbpza) 2 ] (3c) as well as ferric 1:1 complexes [NEt 4 ]-[Fe(bpza)Cl 3 ] (4a) and [NEt 4 ][Fe(bdmpza)Cl 3 ] (4b) [bpza) bis(pyrazol-1-yl)acetate, bdmpza) bis(3,5-dimethylpyrazol-1-yl)acetate] are reported. Complexes 3a, previously reported [Fe(bdmpza) 2 ] (3b), and 3c are high-spin. No spin crossover to the low-spin state was observed in the temperature range of 5−350 K. 4a and 4b are synthesized in one step and in high yield from [NEt 4 ] 2 [Cl 3 FeOFeCl 3 ]. 4a and 4b are iron(III) high-spin complexes. Crystallographic information: 2c (C 24 H 39 ClFeN 4 O 2 ‚CH 2 Cl 2 ‚CH 3 CN) is triclinic, P1 h, a) 12.171(16) Å, b) 12.851(14) Å, c) 13.390-(13) Å, R) 98.61(9)°,) 113.51(11)°, γ) 108.10(5)°, Z) 2; 3a (C 8 H 7 Fe 0.5 N 4 O 2) is monoclinic, P2 1 /n, a) 7.4784(19) Å, b) 7.604(3) Å, c) 16.196(4) Å,) 95.397(9)°, Z) 4; 3c (C 24 H 39 Fe 0.5 N 4 O 2) is monoclinic, P2 1 /n, a) 9.939(6) Å, b) 18.161(10) Å, c) 13.722(8) Å,) 97.67(7)°, Z) 4; 4b (C 20 H 35 Cl 3 FeN 5 O 2) is monoclinic, C2/c, a) 30.45(6) Å, b) 12.33(2) Å, c) 16.17(3) Å,) 118.47(5)°, Z) 8.