N′,N′,N″,N″ ‐Tetramethylguanidine‐Substituted Phosphoryl Compounds as Ligands in Transition Metal Chemistry – Unusual Modes of Coordination

Methyl‐ and tert ‐butylphosphonic bis( N′,N′,N″,N″ ‐tetramethylguanidinide) 1 and 2 were allowed to react with various transition metal compounds. The resulting complexes were studied by IR spectroscopy, mass spectrometry and, in the case of 10 , by NMR spectroscopy. In the case of the compounds 7–10 the metal was coordinated only via the imino nitrogen atoms of 2 , (IR evidence). X‐ray structure analyses were performed for [L 1 CoBr 2 ] 2 6 , L 2 CuCl 2 9 , and L 2 PdCl 2 10 (L 1 = 1 , L 2 = 2 ). In 5 L 1 acts as an N,O bridging ligand, leading to tetrahedral coordination at Co and eightmembered (‐Co‐O‐P‐N‐) 2 rings. In 6 coordination by L 2 chelates the metal atom through two N atoms, leading to PN 2 M rings; the coordination geometry is distorted planar.