Synthesis and Structural Characterization of an Unusual Heterometallic Europium(III) Amidinate Complex

The reaction of EuI 2 (THF) 2 with 3 equiv. of the recently discovered lithium‐cyclopropylethinylamidinate Li[ c ‐C 3 H 5 –C≡C–C(NCy) 2 ] ( 1 ) (Cy = cyclohexyl) unexpectedly afforded the heterometallic europium(III) amidinate complex [{ c ‐C 3 H 5 –C≡C–C(NCy) 2 }Li{ c ‐C 3 H 5 –C≡C–C(NCy) 2 } 2 Eu(μ‐I) 2 Li(THF) 2 ] ( 2 ) in the form of bright yellow, air‐ and moisture‐sensitive crystals. An X‐ray diffraction study of 2 revealed several unusual structural features. It comprises a double “ate” complex of the tentative trivalent europium(III) bis(cyclopropylethinylamidinate) derivative [ c ‐C 3 H 5 –C≡C–C(NCy) 2 ] 2 Eu III I. “Ate” complex formation occurred not only through retention of one equiv. of lithium iodide but also through addition of one equiv. of Li[ c ‐C 3 H 5 –C≡C–C(NCy) 2 ]. The Li atom in the iodo‐bridged Eu(μ‐I) 2 Li(THF) 2 part of the molecule is tetrahedrally coordinated, whereas the second lithium atom is only tricoordinate through the presence of a rare monodentate (dangling) amidinate ligand.