Controlling Catenation in Germanium(I) Chemistry through Hemilability
Alexa Caise, Liam P. Griffin, Andreas Heilmann, Caitilín McManus, Jesús Campos, Simon Aldridge
Abstract
Abstract We present a novel approach for constructing chains of Group 14 metal atoms linked by unsupported metal–metal bonds that exploits hemilabile ligands to generate unsaturated metal sites. The formation/nature of catenated species (oligo‐dimetallynes) can be controlled by the use of (acidic/basic) “protecting groups” and through variation of the ligand scaffold. Reduction of Ar NiPr2 GeCl (Ar NiPr2 =2,6‐( i Pr 2 NCH 2 ) 2 C 6 H 3 )—featuring hemilabile N i Pr 2 donors—yields (Ar NiPr2 Ge) 4 ( 2 ), which contains a tetrameric Ge 4 chain. 2 represents a novel type of a linear homo‐catenated Ge I compound featuring unsupported E−E bonds. Trapping experiments reveal that a key structural component is the central two‐way Ge=Ge donor‐acceptor bond: reactions with IMe 4 and W(CO) 5 (NMe 3 ) give the base‐ or acid‐stabilized digermynes (Ar NiPr2 Ge(IMe 4 )) 2 ( 4 ) and (Ar NiPr2 Ge{W(CO) 5 }) 2 ( 5 ), respectively. The use of smaller N ‐donors leads to stronger Ge‐N interactions and quenching of catenation behaviour: reduction of Ar NEt2 GeCl gives the digermyne (Ar NEt2 Ge) 2 , while the unsymmetrical system Ar NEt2 GeGeAr NiPr2 dimerizes to give tetranuclear (Ar NEt2 GeGeAr NiPr2 ) 2 through aggregation at the N i Pr 2 ‐ligated Ge I centres.