Synthesis and Characterization of New Iron Complexes Induced with y-Ray Irradiation

材料。 Fe2(C2O4)3·6H2O、[LaFe(C2O4)3]·9H2O、[bipyH][Fe(C2O4)2(H2O)2]·H2O、[phenH][Fe(C2O4)2(H2O)2] H2O、(Hpy)2[Fe2(C6H4O7)2(H2O)2]、制备(Hbpiy)2[Fe2(C6H4O7)2(H2O)2]和(Hphen)3[Fe2(C6H4O7)3]络合物并用60Co γ射线照射。在这些配合物中观察到新的铁 (II) 物质。通过穆斯堡尔谱和 XRD，将辐照后的新铁（II）高自旋物种 Fe2(C2O4)3.6H2O 和 [LaFe(C2O4)3]·9H2O 归属为 FeC2O4·2H2O。然而，新的铁(II)高自旋物种[bipyH][Fe(C2O4)2(H2O)2] H2O、[phenH][Fe(C2O4)2(H2O)2]·H2O和柠檬酸铁与FeC2O4·2H2O不同。在辐射化学中众所周知，三草酸铁酸(III)中铁原子的还原与草酸阴离子C2O42-→2CO2 2e-的辐射分解有关。在该体系中，Fe(II) 物质的形成由相同的原因解释。在 [bipyH][Fe(C204)2(H20)·H2O、[phenH][Fe(C2O4)2(H2O)·H2O、(Hbpiy)2[Fe2(C6H4O7)2(H2O)2] 和 ( Hphen)3[Fe2(C6H4O7)3] 配合物中，另一个随着辐照剂量的增加，发现了新的Fe(II)低自旋物种。通过穆斯堡尔谱将其新物种归属为Fe(bipy)33和Fe(phen)33。这一结果可以通过 Fe2+ 离子与抗辐射的联吡啶和菲咯啉配体的反应来解释。丙二酸铁配合物 K3[Fe(C2H2O4)3]·3H2O 在 y 射线照射下也观察到了 Fe(II) 高自旋物种。在 K3Fe(C2O4)3 与 Co(bipy)3·Cl2 和 Co(phen)3·Cl2 的混合物中，由于 K3Fe(C2O4)3 本身观察到了 Fe(II) 高自旋物种，但没有发现新的 Fe(II) 低自旋物种。这表明Co-bipy和Co-phen的化学键强度大于Fe-bipy和Fe-phen。辐照后的(Hphen)3[Fe(CN)6]·5H2O和(Hphen)3[Fe(CN)5NO]·2H2O中未发现新的铁物种。这表明CN配体的抗辐射能力强于草酸盐、柠檬酸盐和丙二酸盐配体。我们通过y射线辐照含有草酸盐、柠檬酸盐、丙二酸盐的铁配合物得到了新的铁物种。

Materials. Fe2(C2O4)3・6H2O, [LaFe(C2O4)3]・9H2O, [bipyH][Fe(C2O4)2(H2O)2]・H2O,[phenH][Fe(C2O4)2(H2O)2] H2O, (Hpy)2[Fe2(C6H4O7)2(H2O)2], (Hbpiy)2[Fe2(C6H4O7)2(H2O)2] and (Hphen)3[Fe2(C6H4O7)3] complexes were prepared and irradiated with 60Co γ-ray. New iron(II) species were observed in these complexes. New iron(II) high-spin species of irradiated Fe2(C2O4)3.6H2O and [LaFe(C2O4)3]・9H2O were assigned to FeC2O4・2H2O by using Mossbauer spectroscopy and XRD. However, new iron(II) high-spin species of [bipyH][Fe(C2O4)2(H2O)2] H2O, [phenH][Fe(C2O4)2(H2O)2] ・H2O and iron citrate were different with FeC2O4・2H2O. It is well known in radiation chemistry that the reduction of iron atoms in trisoxalatoferrate(III) is associated with following radiolysis of oxalate anions, C2O42-→2CO2 + 2e-. In this system, formation fo Fe(II) species is explaine by the same reason.In [bipyH][Fe(C204)2(H20)・H2O, [phenH][Fe(C2O4)2(H2O)・H2O, (Hbpiy)2[Fe2(C6H4O7)2(H2O)2] and ( Hphen)3[Fe2(C6H4O7)3] complexes, another new Fe(II) low-spin species were found with increase of irradiation dose. Its new species was assigned to Fe(bipy)33+ and Fe(phen)33+ by Mossbauer spectra. This result is explained by the reaction fo Fe2+ ion and bipyridine and phenanthroline ligands which resist radiation. Malonate iron complexe K3[Fe(C2H2O4)3]・3H2O were also observed Fe(II) high-spin species by y-ray irradiation.In mixture of K3Fe(C2O4)3 and Co(bipy)3・Cl2 and Co(phen)3・Cl2, Fe(II) high-spin species was observed due to K3Fe(C2O4)3 itself but new Fe(II) low-spin species was not found. It suggests that the chemical bond strength of Co-bipy and Co-phen greater than those of Fe-bipy and Fe-phen. New iron species were not found in irradiated (Hphen)3[Fe(CN)6]・5H2O and (Hphen)3[Fe(CN)5NO]・2H2O. It suggest that the radiation resisting of CN ligand is stronger than those of oxalate, citrate and malonate ligands.We obtained new iron species by y-ray irradiation of iron complexes containing oxalate, citrate, malonate.