Complexes of Monocationic Group 13 Elements with Pentaphospha- and Pentaarsaferrocene

Reactions of the sandwich complexes [Cp*Fe((5)-E-5)] (Cp*=(5)-C5Me5; E=P (1), As (2)) with the monovalent Group 13 metals Tl+, In+, and Ga+ containing the weakly coordinating anion [TEF] ([TEF]=[Al{OC(CF3)(3)}(4)](-)) are described. Here, the one-dimensional coordination polymers [M(,(5):(1)-E5FeCp*)(3)](n)[TEF](n) (E=P, M=Tl (3a), In (3b), Ga (3c); E=As, M=Tl (4a), In (4b)) are obtained as sole products in good yields. All products were analyzed by single-crystal X-ray diffraction, revealing a similar assembly of the products with (5)-bound E-5 ligands and very weak sigma-interactions between one P or As atom of the ring to the neighbored Group 13 metal cation. By exchanging the [TEF] anion of 4a for the larger [FAl] anion ([FAl]=[FAl{OC6F10(C6F5)}(3)](-)), the coordination compound [Tl{((5)-As-5)FeCp*}(3)][FAl] (5) without any sigma-interactions of the As-5-ring is obtained. All products are readily soluble in CH2Cl2 and exhibit a dynamic coordination behavior in solution, which is supported by NMR spectroscopy and ESI-MS spectrometry as well as by osmometric molecular-weight determination. For a better understanding of the proceeding equilibrium DFT calculations of the cationic complexes were performed for the gas phase and in solution. Furthermore, the P-31{H-1} magic-angle spinning (MAS) NMR spectra of 3a-c are presented and the first crystal structure of the starting material 2 was determined.