Reactivity of Organolanthanide and Organolithium Complexes Containing the Guanidinate Ligands toward Isocyanate or Carbodiimide:  Synthesis and Crystal Structures

• Published in: Inorganic chemistry Vol. 44; no. 3; pp. 716 - 722
• Main Authors: Zhang, Jie, Zhou, Xigeng, Cai, Ruifang, Weng, Linhong
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 07.02.2005
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic048683x

The direct reactions of (C5H5)2LnCl with LiNC(NMe2)2 proceeded at room temperature in THF under pure nitrogen to yield the lanthanocene guanidinate complexes [(C5H5)2Ln(μ-η 1:η 2-NC(NMe2)2)]2 (Ln = Gd (1), Er (2)). Treatment of phenyl isocyanate with complexes 1 and 2 results in monoinsertion of phenyl isocyanate into the Ln−N(μ-Gua) bond to yield the corresponding insertion products [(C5H5)2Ln(μ-η 1:η 2-OC(NC(NMe2)2)NPh)]2 (Ln = Gd (3), Er (4)), presenting the first example of unsaturated organic small molecule insertion into the metal−guanidinate ligand bond. Further investigations indicate that N,N‘-diisopropylcarbodiimide does not react with complexes 1 and 2 under the same conditions; however, it readily inserts into the lithium−guanidinate ligand bond of LiNC(NMe2)2. As a synthon of the insertion product Li[( i PrN)2C(NC(NMe2)2)], its reaction with (C5H5)2LnCl gives the novel organolanthanide complexes containing the guanidinoacetamidinate ligand, (C5H5)2Ln[( i PrN)2C(NC(NMe2)2)] (Ln = Yb (5), Er (6), Dy (7)). All complexes were characterized by elemental analysis and spectroscopic properties. The structures of complexes 1, 3, 5 and 7 were determined through X-ray single-crystal diffraction analysis.