Abstract
The coordination behavior of 1,2,4-triphosphaferrocenes [FeCpR(eta(5)-P(3)C(2)tBu(2))] [Cp-R = Cp (1), Cp''' = eta(5)-C(5)H(2)tBu(3) (3)] towards Cu-I halides is significantly influenced by the substitution pattern of the cyclopentadienyl ring attached to the iron atom. The reaction of the Cp derivative 1 with CuBr in a 1:1 stoichiometry leads to the dimeric complex ...
Abstract
The coordination behavior of 1,2,4-triphosphaferrocenes [FeCpR(eta(5)-P(3)C(2)tBu(2))] [Cp-R = Cp (1), Cp''' = eta(5)-C(5)H(2)tBu(3) (3)] towards Cu-I halides is significantly influenced by the substitution pattern of the cyclopentadienyl ring attached to the iron atom. The reaction of the Cp derivative 1 with CuBr in a 1:1 stoichiometry leads to the dimeric complex [{FeCp(eta(5):eta(1):eta(1)-P(3)C(2)tBu(2))}{mu-CuBr(MeCN)}](2) (5b), in which two 1,2,4-triphosphaferrocenes are linked by two CuBr units. By using a 1:2 stoichiometry, the 1D polymeric compound [{FeCp(eta(5):eta(1):eta(1):eta(1)-P(3)C(2)tBu(2))}mu-{(CuBr)(3)(MeCN)(2)}](n) (6) is formed in which the triphosphaferrocenes are bridged by (CuBr) 2{CuBr(MeCN) 2} units. Starting from CuI, independent of the stoichiometry, the cage compound [{FeCp(eta(5):eta(1):eta(1)-P(3)C(2)tBu(2))}(3){Cu(mu-I)}(3){Cu(mu(3)-I)}(3){Cu(NCMe)}(mu(6)-I)] (7) is formed. However, if the bulky Cp''' derivative 3 is used already in a 1:1 stoichiometry with CuBr, a transformation of the initially five-membered 1,2,4-triphospholyl ring into a four-membered 1,2-diphosphete ligand is observed, which is linked by CuBr moieties forming the dimeric paramagnetic complex [{FeCp'''(eta(4):eta(1):eta(1)-P(2)C(2)tBu(2))}(mu-CuBr)](2) (9). Furthermore, applying a 1:2 stoichiometry between 3 and CuX (X = Br, I) the complete fragmentation of the 1,2,4-triphospholyl ring under mild conditions into a tetraphosphabutadiene ligand is observed. In the formed 1D polymeric complexes [{(FeCp''') 2(mu,eta(4):eta(1):eta(1)-P-4)}{(mu-CuX)(2)(MeCN)}] n [X = Br (10a), I (10b)] this ligand represents now the middle deck of the triple-decker sandwich complexes linked by four-membered [(CuX)(2)(CH3CN)] moieties. Moreover, the reaction of the Cp derivative 1 with the Ag salt of the weakly coordinating anion [Al{OC(CF3)(3)}](4)(-) leads to the dimeric Ag(CH3CN)-bridged dicationic product [{FeCp(eta(5)-P(3)C(2)tBu(2))} Ag-(MeCN)](2)[Al{OC(CF3)(3)}(4)](2) (11).
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