Rare‐Earth Complexes Coordinated by ansa ‐Bis(amidinate) Ligands with m ‐Phenylene, 2,6‐Pyridinediyl, and SiMe 2 Linkers

The salt‐metathesis reactions of anhydrous LnCl 3 (Ln = Y, Er) with [1,3‐C 6 H 4 {NC(Ph)NSiMe 3 } 2 Li 2 (thf) 2 ] 2 ( 1 ; thf = tetrahydrofuran) in a 2:1 molar ratio in thf afford tris(amidinate) complexes [(1,3‐C 6 H 4 {NC(Ph)NSiMe 3 } 2 ) 3 Y(thf)Y(µ‐Cl)Li(thf) 3 ] ( 3 ) and [(1,3‐C 6 H 4 {NC(Ph)NSiMe 3 } 2 ) 3 Er 2 (µ‐Cl)Li(thf) 3 ] ( 4 ), which feature bridging coordination of the amidinate ligands to two Ln 3+ ions. The reactions of the dilithium derivative of the related bis(amidine) with a 2,6‐pyridinediyl linker, [2,6‐C 5 H 3 N{NC( t Bu)N(2,6‐Me 2 C 6 H 3 )} 2 ] 2– , with LnCl 3 (Ln = Y, Er) result in the formation of mononuclear chlorido bis(ligand) ate complexes [{(2,6‐C 5 H 3 N)(NC{ t Bu}N{2,6‐Me 2 C 6 H 3 }) 2 }({2,6‐C 5 H 3 N}{NC( t Bu)N(2,6‐Me 2 C 6 H 3 )}{NC( t Bu)NH(2,6‐Me 2 C 6 H 3 )})LnCl][Li(dme) 3 ] [Ln = Y ( 5 ), Er ( 6 ); dme = 1,2‐dimethoxyethane]. The Ln 3+ ions in these complexes are coordinated by one dianionic tridentate amidopyridinate–amidinate ligand, and the second ligand is a monoanionic amidopyridinate. The reaction of YbCl 3 with [(Me 2 Si{NC(Ph)N(2,6‐ i Pr 2 C 6 H 3 )} 2 ) 2 Li 3 ][Li(thf) 4 ], which contains a short SiMe 2 linker, in a 2:1 molar ratio in thf afforded the bis(amidinate)chloridoytterbium complex [(Me 2 Si{NC(Ph)N(2,6‐ i Pr 2 C 6 H 3 )} 2 ) 2 (Yb 2 Cl)(µ‐Cl) 2 Li(thf) 3 ] ( 8 ). The magnetic properties of 4 were investigated through superconducting quantum interference device (SQUID) magnetometry.