Synthesis, Crystal Structures and Hirshfeld Surface Analysis of Bis-[(di(2-methoxyphenyl)phosphoroselenoyl)-2,4-cyclopentadien-1-yl] iron(II) and Ruthenium(II)η6-arene Complex of Bis-[(di(2-allylphenyl) phosphonite)-2,4-cyclopentadien-1-yl]iron (II)

Ferrocenylbis(phosphonites), [Fe(C5H4P(OR)(2))(2) (2, R= -C6H4(OMe-o); 3, R = -C6H4(C3H5-o))] were synthesized by the reaction of Fe(C5H4PCl2)(2) (1) with 2-methoxyphenol and 2-allylphenol. The reaction of 2 with elemental selenium afforded bisselenide, [Fe{C5H4P(Se)(OC6H4(OMe-o))(2)}(2)] (4). Equimolar reaction between 3 and [RuCl2(eta(6)-p-cymene)](2) yielded [{Ru2Cl4(eta(6)-p-cymene)(2)}Fe C5H4P(OC6H4(C3H5-o))(2)}(2)] (5) in good yield. Bisselenide (4) and ruthenium(II) complex (5) were characterized by single-crystal X-ray analysis. In compound 4, the geometry around phosphorus atoms is distorted tetrahedral. In case of complex 5, ruthenium atoms containing eta(6)-p-cymene, two chlorides and one phosphine moiety display a typical three-legged "piano-stool" structure. The molecule has crystallographically imposed centrosymmetry. A Hirshfeld surface analysis indicates that the most significant contributions to the crystal packing of compound 4 are from H center dot center dot center dot H (50.1%), C center dot center dot center dot H/H center dot center dot center dot C (24.1%), Se center dot center dot center dot H/H center dot center dot center dot Se (13.4%), O center dot center dot center dot H/H center dot center dot center dot O (10.8%) contacts, and in the case of complex 5 are from H center dot center dot center dot H (73.3%), C center dot center dot center dot H/H center dot center dot center dot C (15.8%), Cl center dot center dot center dot H/H center dot center dot center dot Cl (10%) contacts. [GRAPHICS] .