Terphenyl‐Ge as μ 2 ‐Ge‐bis(hexahapto‐Trip) Bridging Ligand to Form a New Transition Metal‐Only Chelating Lewis Base

• Published in: Chemistry : a European journal 2024-11
• Main Authors: Manegold, Johanna, Ebisch, Adrian, Eichele, Klaus, Schubert, Hartmut, Wesemann, Lars
• Format: Article
• Language: English
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202404201

Terphenylgermanium Ar*Ge [Ar*=C 6 H 3 (2,6‐Trip) 2 , Trip=2,4,6‐C 6 H 2 i Pr 3 ] was found to act as a novel μ 2 ‐Ge‐bis(hexahapto‐Trip) bridging ligand. Deprotonated terphenyl germanium trihydride [Li(thf) 3 ][Ar*GeH 2 ] ( 1 ) undergoes reductive elimination and transfer of hydrogen in reaction with dimeric [(COD)RhCl] 2 to yield the dinuclear complex [Ar*GeRh(COE)RhCl(COD)] ( 2 ). Subsequent chloride abstraction from compound 2 using Na[BAr F 4 ] or Li[Al(O t Bu F ) 4 ] results in the cationic complexes [Ar*GeRh(COE)Rh(COD)][WCA] ( 3 ) {WCA: [BAr F 4 ] − (Ar F =C 6 H 3 –3,5‐(CF 3 ) 2 ), [Al(O t Bu F ) 4 ] − }. Ligand exchange of olefin for CO yields the carbonyl complex [Ar*Ge(Rh(CO)) 2 ][BAr F 4 ] ( 4 ). In an alternative approach to the synthesis of carbonyl complex 4 , [Li(thf) 3 ][Ar*GeH 2 ] ( 1 ) was treated with [Rh(CO) 2 Cl] 2 leading to the isolation of a hexanuclear rhodium cluster [( μ 3 ‐Ar*Ge) 2 {Rh(CO) 2 } 6 ( μ 3 ‐H) 2 ] ( 5 ) in reasonable yield. In reactions with [Rh(CO) 2 Cl] 2 or [Ph 3 PAuCl] complex 4 abstracts the chloride ligand and forms tetranuclear complexes featuring a GeRh 3 ‐ or GeRh 2 Au‐rectangle, [Ar*GeCl(Rh 3 (CO) 4 )][BAr F 4 ] ( 6 ), or [Ar*GeCl{Rh 2 (CO) 2 }(AuPPh 3 )][BAr F 4 ] ( 7 ).