Radical-Type Reactivity of Metalla[1.1.1]propellanes of Group 14: Syntheses, Structures, and Reduction Chemistry of Transition Metal-Terminated Bicyclo[1.1.1]pentastannanes

Two selected metalla[1.1.1]propellanes of group 14, Sn5Dep6 (1) and Ge5Mes6 (2) (Dep = 2,6-Et2C6H3, Mes = 2,4,6-Me3C6H2), were reacted with [FeCp(CO)2]2 and [RuCp(CO)2]2. While 2 did not show any reaction with [FeCp(CO)2]2 or did not lead to any isolable product in the case of [RuCp(CO)2]2, the tin propellane 1 quantitatively (monitored by 1H NMR) afforded the first transition metal-terminated bicyclo[1.1.1]pentastannanes, [{MCp(CO)2}2{μ-Sn5Dep6}] (M = Fe (3), Ru = (4)), in 68% (3) and 66% (4) isolated yield. This behavior confirms the radical-type reactivity of metalla[1.1.1]propellanes, in this case 1. The title compounds 3 and 4 have been characterized in detail using various methods. X-ray structure analyses corroborated that the two ligand-free bridgehead tin atoms within the Sn5 scaffold are bonded to the transition metal fragments. Electrochemical studies revealed the reduction chemistry of 3 and 4 in THF solutions to be very interesting. A detailed preparative and electrochemical study, including the isolation and characterization of the monosubstituted cobaltocenium salt [CoCp*2]+[{FeCp(CO)2}{Sn5Dep6}]− (5), elucidated a complex redox cycle consisting of a cascade of bond-breaking and bond-making processes

Synthesis, Characterization, and X-ray Structure Determination of [Au₁₈(P)₂(PPh)₄(PHPh)(dppm)₆]Cl₃^#

The reaction of [(AuCl)2dppm] (dppm = Ph2PCH2PPh2) with PhP(SiMe3)2 and P(SiMe3)3 leads to the formation of the gold cluster compound [Au18(P)2(PPh)4(PHPh)(dppm)6]Cl3 (1). The crystal structure investigation shows a central Au7P2 unit formed by two P centered gold tetrahedra sharing the central gold corner. This central unit is surrounded by a 10-membered Au5P5 ring which, together with the remaining six gold atoms, builds two Au4P rectangular and two Au3P trigonal pyramids. The different structure motifs are connected by the phosphine ligands. The compound has been characterized using microanalysis, IR spectroscopy, ESI-MS, and 31P NMR techniques. Luminescence measurements have also been carried out