Potential of Mixed Dipnictogen Molybdenum Complexes in the Self-Assembly of Thallium Coordination Compounds.

The coordination chemistry of the homo- and heterodipnictogen tetrahedrane complexes [{CpMo(CO) 2 } 2 (μ,η 2:2 -EE')] (E, E' = P, As, Sb) ( A-F ) toward Tl[BArF 24 ] ([BArF 24 ] - = [B(3,5-C 6 H 3 (CF 3 ) 2 ) 4 ] - ) was studied. Controlled by the used tetrahedranes A-F , and thus depending on the respective pnictogen atoms, the monomers [Tl(η 2 - A )][BArF 24 ] ([ A ] Tl ) and [Tl(η 2 - B )][BArF 24 ] ([ B ] Tl ), the double substituted [Tl(η 1 - C ) 2 ][BArF 24 ] ([ C ] 2 Tl ) or the even higher aggregated compounds [Tl 2 (η 2 - D ) 3 (μ,η 2:1 - D )(μ,η 1:1 - D )][BArF 24 ] 2 ([ D ] 5 Tl 2 ), [Tl 2 (η 2 - E ) 2 (μ,η 2:1 - E ) 3 ] [BArF 24 ] 2 ([ E ] 5 Tl 2 ) and [Tl 2 (η 2 - F ) 3 (μ,η 2:1 - F ) 3 ][BArF 24 ] 2 ([ F ] 6 Tl 2 ) were obtained. Utilization of [BArF 24 ] - promises additional stabilization of Tl I via η 6 -coordination of two of its aryl rings as found in compounds [ A ] Tl , [ B ] Tl and [ C ] 2 Tl . Within the series of reactivity of A-F , the heavier congeners D , E and F tend to form larger aggregates in which σ(E-E') bond contributions to the coordination behavior were observed. Interatomic distances suggest the presence of Tl···Tl interactions in [ E ] 5 Tl 2 and [ F ] 6 Tl 2 . The features of the respective coordination compounds were studied in the solid-state as well as in solution. For the latter at least a partial dissociation of the assemblies in solution was indicated. The isolated solid-state aggregates are the first examples of heterodipnictogen units as ligands in self-assembled Tl I -based coordination compounds.