Low-Valent Titanium-Pentafulvene Complexes - Formation of Dinuclear Titanium-Nitrogen Complexes

• Published in: European Journal of Inorganic Chemistry 2005-03, Vol.2005 (6), p.1003-1010
• Main Authors: Scherer, Axel, Kollak, Kay, Lützen, Arne, Friedemann, Marion, Haase, Detlev, Saak, Wolfgang, Beckhaus, Rüdiger
• Format: Article
• Language: English
• Subjects: Bridging ligands; Fulvene ligands; Metallocenes; Nitrogen; Titanium
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.200400938

Sodium amalgam reduction of [(η5‐C5Me5)TiCl3] (1) in the presence of the pentafulvenes {C5H4=CR2, R: p‐tol (2), p‐FPh (3), CR2: adamantyl (4)} under nitrogen smoothly produces dark green or dark blue dinuclear low‐valent titanium complexes [{(η5‐C5Me5)Ti(η6‐C5H4=CR2)}2(μ2,η1,η1‐N2)] {R: p‐tol (6), p‐FPh (7), CR2: adamantyl (8)}, characterized by a bridging end‐on coordinated dinitrogen ligand, in high yield. In the same way, the nitrogen‐free, low‐coordinated complex [(η5‐C5Me5)Ti(η6‐C9H6=C(p‐tol)2)] (10) is obtained by using the more sterically demanding benzofulvene C9H6=C(p‐tol)2 (5) instead of 2–4. The solid‐state structures of the dinitrogen compounds reveal weakly activated end‐on bound N2 ligands with identical N–N distances of 1.160(3) Å (6) and 1.160(5) Å (8). The dinitrogen complexes 6, 7 and 8 show diamagnetic behaviour, which allowed a complete NMR spectroscopic characterization. So a correlation between the situation in solution, measured by NMR, and in the solid state (X‐ray diffraction) becomes possible and shows a congruent picture. A broad range of reactions can be imagined concerning the easily replaceable dinitrogen ligand as well as the known reactivity of fulvene ligands in complexes of early transition metals. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)