Size-determining dependencies in supramolecular organometallic host-guest chemistry |
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Authors: | Schindler Andrea Heindl Claudia Balázs Gábor Gröger Christian Virovets Alexander V Peresypkina Eugenia V Scheer Manfred |
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Affiliation: | 1. Institut für Anorganische Chemie der Universit?t Regensburg, 93040 Regensburg (Germany), Fax: (+49) 941‐943‐4439;2. Nikolaev Institute of Inorganic Chemistry Siberian Division of RAS, Acad. Lavrentyev prosp. 3, 630090 Novosibirsk (Russia) |
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Abstract: | Treatment of the pentaphosphaferrocene [Cp*Fe(η5‐P5)] with CuI halides in the presence of different templates leads to novel fullerene‐like spherical molecules that serve as hosts for the templates. If ferrocene is used as the template the 80‐vertex ball [Cp2Fe]@[{Cp*Fe(η5‐P5)}12{CuCl}20] ( 4 ), with an overall icosahedral C80 topological symmetry, is obtained. This result shows the ability of ferrocene to compete successfully with the internal template of the reaction system [Cp*Fe(η5‐P5)], although the 90‐vertex ball [{Cp*Fe(η5:η1:η1:η1:η1:η1‐P5)}12(CuCl)10(Cu2Cl3)5{Cu(CH3CN)2}5] ( 2 a ) containing pentaphosphaferrocene as a guest is also formed as a byproduct. With use of the triple‐decker sandwich complex [(CpCr)2(μ,η5‐As5)] as a template the reaction between [Cp*Fe(η5‐P5)] and CuBr leads to the 90‐vertex ball [(CpCr)2(μ,η5‐As5)]@[{Cp*Fe(η5‐P5)}12{CuBr}10{Cu2Br3}5{Cu(CH3CN)2}5] ( 6 ), in which the complete molecule acts as a template. However, if the corresponding reaction is instead carried out with CuCl, cleavage of the triple‐decker complex is found and the 80‐vertex ball [CpCr(η5‐As5)]@[{Cp*Fe(η5‐P5)}12{CuCl}20] ( 5 ) is obtained. This accommodates as its guest [CpCr(η5‐As5)], which has only 16 valence electrons in a triplet ground state and is not known as a free molecule. The triple‐decker sandwich complex [(CpCr)2(μ,η5‐As5)] requires 53.1 kcal mol?1 to undergo cleavage (as calculated by DFT methods) and therefore this reaction is clearly endothermic. All new products have been characterized by single‐crystal X‐ray crystallography. A favoured orientation of the guest molecules inside the host cages has been identified, which shows π???π stacking of the five‐membered rings (Cp and cyclo‐As5) of the guests and the cyclo‐P5 rings of the nanoballs of the hosts. |
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Keywords: | fullerene‐like topologies host–guest systems phosphorus self‐assembly supramolecular chemistry |
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