Farid M. Sroor

Synthesis and catalytic activity of homoleptic lanthanide-tris(cyclopropylethinyl)amidinates

Reactions of anhydrous lanthanide trichlorides, LnCl3 (Ln = Nd, Sm, Ho), with 3 equiv. of lithium-cyclopropylethinylamidinates, Li[c-C3H5–CC–C(NR)2] (1a: R = cyclohexyl (Cy), 1b: R = iPr), afforded the new homoleptic lanthanide(III) tris(cyclopropylethinylamidinate) complexes [c-C3H5–CC–C(NCy)2]3Sm (2a) and [c-C3H5–CC–C(NiPr)2]3Ln (Ln = Nd (2b), Sm (2c), Ho (2d)) as air- and moisture-sensitive crystalline solids in moderate to good isolated yields (45–79%). The formation of unsolvated, homoleptic Ln(III) tris(cyclopropylethinylamidinate) was confirmed by an X-ray diffraction study of the holmium derivative [c-C3H5–CC–C(NiPr)2]3Ho (2d). EI mass spectra of the new rare-earth metal amidinates indicated a significant volatility. An initial catalysis study revealed that these complexes catalyze the addition of terminal alkynes to carbodiimides to give propiolamidines of the type R–CC–C(NR′)(NHR′). The molecular structure of N,N′-dicyclohexyl-phenylpropiolamidine, Ph–CC–C(NCy)(NHCy) (4), was also determined by X-ray diffraction.

Crystal structures of two ytterbium(III) complexes comprising alkynylamidinate ligands

Two ytterbium(III) complexes comprising alkynylamidinate ligands, Cp2Yb[(iPr2N)2C—C≡C—c-C3H5] (1) and Yb[(CyN)2C—C≡C—Ph]3 (Cy = cyclohexyl) (2) have been synthesized and structurally characterized. Both complexes are monomers without any coordinated solvent in the solid state.

Formation and structure of the first metal complexes comprising amidino­guanidinate ligands

The first metal complexes comprising amidinoguanidinate ligands have been prepared and structurally characterized, namely bis[μ-N,N′,N′′,N′′′-tetraisopropyl-1-(1-butylamidinato)guanidinato-κ3 N 1,N 2:N 2) bis[(tetrahydrofuran)lithium] and [bis(tetrahydrofuran)lithium]-di-μ-chlorido-[N,N′,N′′,N′′′-tetracyclohexyl-1-(1-butylamidinato)guanidinato-κ2 N 1,N 2](N,N′-dicyclohexyl-1-butylamidinato-κ2 N 1,N 2)holmate(III).