Abstract
New unsolvated, homoleptic lanthanide(iii) tris(cyclopropylethinylamidinate) complexes of the type [c-C3H5–CC–C(NR)2]3Ln (R = iPr, cyclohexyl; Ln = Nd, Sm, Ho) have been prepared and the crystal structure of the holmium derivative [c-C3H5–CC–C(NiPr)2]3Ho has been confirmed by X-ray diffraction.
Highlights
In organolanthanide chemistry, steric saturation of the coordination sphere of the large rare-earth metal cations is generally more important than the electron count
In a first contribution we described the synthesis and full characterization of the lithium-cyclopropylethinylamidinates Li[c-C3H5–CRC–C(NR)2] (1a: R = cyclohexyl (Cy), 1b: R = iPr).[10]
2.1 Synthesis and structure The starting materials used in this study, the lithium-cyclopropylethinylamidinates Li[c-C3H5–CRC–C(NR)2] (1a: R = Cy, 1b: R = iPr), were prepared in a straightforward manner according to Scheme 1 by in situ-deprotonation of commercially available cyclopropylacetylene followed by treatment with either N,N0-diisopropylcarbodiimide or N,N0-dicyclohexylcarbodiimide according to the published procedure
Summary
Steric saturation of the coordination sphere of the large rare-earth metal cations is generally more important than the electron count. Anionic amidinate ligands of the type [RC(NR0)2]À (R = H, alkyl, aryl; R0 = alkyl, cycloalkyl, aryl, SiMe3) have been demonstrated to be highly useful and versatile in that respect. These readily available N-chelating ligands are generally regarded as steric cyclopentadienyl equivalents.[1] In the case of rare-earth metals, mono-, di- and trisubstituted lanthanide amidinate and guanidinate complexes are all accessible, just like the mono-, di- and tricyclopentadienyl complexes. Various rare-earth metal amidinates have been reported to be very efficient homogeneous catalysts e.g. for ring-opening polymerization reactions of lactones, the guanylation of amines or the addition of terminal alkynes to carbodiimides.[2] In materials science, homoleptic alkyl-substituted lanthanide tris(amidinate) complexes are often. We report the synthesis and structural characterization of the first homoleptic Ln(III) tris(cyclopropylethinylamidinate) complexes as well as an initial study of their possible use as homogeneous catalysts for the addition of terminal alkynes to carbodiimides
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
