Unprecedented Formation of Novel Phosphonodithioate Ligands from Diferrocenyldithiadiphosphetane Disulfide

The reaction of the phosphetane disulfide, FcP(S)S2P(S)Fc (1) (Fc = (η5-C5H5)Fe(η5-C5H4)), the ferrocenyl analogue of the Lawesson reagent, with gold and palladium complexes leads to the unprecedented formation of phosphonodithioate ligands upon coordination to the metal centers. The reaction of 1 with gold complexes such as [AuCl(PR3)] affords the species [Au{S2P(OH)Fc}(PR3)] (PR3 = PPh3 (2), PPh2Me (3)), in which the phosphonodithioate ligand Fc(OH)PS2− has been formed. The same ligand is present in the compound [Au2{S2P(OH)Fc}2]·[N(PPh3)2]Cl (4), obtained by reaction of 1 with [N(PPh3)2][AuCl2]. It crystallizes with one molecule of [N(PPh3)2]Cl, whereby complex 4 acts as an anion receptor and forms strong hydrogen bonds between the chloro and the hydroxyl groups. The reaction with palladium derivatives is different; two complexes, [Pd2(S4OP2Fc2)2] (5) and [Pd4Cl4(S4OP2Fc2)2] (6), are obtained in molar ratio 2:1 and 1:1, respectively. In these complexes a new phosphonodithioate ligand is present and probably arises from the condensation of two molecules of Fc(OH)PS2−. Complex 5 has also been characterized by X-ray methods.

磷杂环丁烷二硫化物FcP(S)S₂P(S)Fc（1，其为劳森试剂（Lawesson reagent）的二茂铁类似物，其中Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)），与金、钯配合物发生反应时，会在与金属中心配位后生成前所未有的二硫代膦酸酯配体。当1与[AuCl(PR₃)]这类金配合物反应时，可得到物种[Au{S₂P(OH)Fc}(PR₃)]（PR₃=三苯基膦（PPh₃，2）、甲基二苯基膦（PPh₂Me，3）），其中已生成二硫代膦酸酯配体Fc(OH)PS₂⁻。该配体同样存在于化合物[Au₂{S₂P(OH)Fc}₂]·[N(PPh₃)₂]Cl（4）中，该化合物由1与[N(PPh₃)₂][AuCl₂]反应制得。它与1分子[N(PPh₃)₂]Cl共结晶，此时配合物4可作为阴离子受体，在氯离子与羟基之间形成强氢键相互作用。而与钯衍生物的反应则有所不同：当反应摩尔比分别为2:1和1:1时，可得到两种配合物[Pd₂(S₄OP₂Fc₂)₂]（5）与[Pd₄Cl₄(S₄OP₂Fc₂)₂]（6）。在这类配合物中存在一种新型二硫代膦酸酯配体，其可能由两分子Fc(OH)PS₂⁻缩合生成。配合物5也已通过X射线衍射法完成结构表征。