Oligomer and Polymer: Self Assembly of [Cp*Fe(η5-P5)] and Ag(I) Salts of Bulky Weakly Coordinating Anions

Reactions between the five-fold symmetric building block [Cp*Fe(eta(5)-P-5)] (A) and Ag(I) salts containing bulky weakly coordinating anions [TEF] and [FAL] ([TEF]=[Al{OC(CF3)(3)}(4)](-), [FAl]=[FAl{OC6F10(C6F5)}(3)](-)) are presented. While, in the presence of Ag[TEF], A leads to the formation of a hitherto condensed 1D coordination polymer [{Ag(eta(2):eta(1)-A)(2)}](n)[TEF](n) (1), a new finite tetranuclear Ag(I) complex [{Ag-4(eta(1)-A)(2)(eta(2):eta(1)-A)(4)(eta(1):eta(1)-A)(2)}][FAL](4) (3) was obtained with an Ag(I) salt bearing the weakly coordinating anion [FAl] increased in size. Various coordination modes (eta(2):eta(1); eta(1):eta(1) and eta(1)) of A were observed in the solid-state structure of 3, reflecting the adaptive coordination behavior of A towards Ag(I) ions. Structural modifications of the 1D polymer (1) can be controlled by the addition of a limited amount of MeCN yielding the unwound heteroleptic 1D polymer [{Ag(MeCN)(2)}(3)(eta(1):eta(1):eta(1)-A)(2)](n)[TEF](3n) (2). Moreover, in the presence of MeCN, the finite oligomeric compound 3 can also be converted into a new heteroleptic 1D polymer [{Ag(MeCN)}(4)(eta(1):eta(1)-A)(5)(eta(2):eta(1)-A)(2)](n)[FAL](4n) (4). The solid-state structure of 4 discloses the existence of a unique 1,1,2-eta(2):eta(1) (pi,sigma) coordination of A along with 1,3-eta(1):eta(1) (sigma) and 1,2-eta(1):eta(1) (sigma) coordination modes, while 1,2,4-eta(1):eta(1):eta(1) (sigma) coordination modes of A were found in 2. As revealed by X-ray crystallography, in all the cases, the cationic moieties are well separated from the weakly coordinating anions in the solid state.