Crystal Structure of Tricarbonyl Complexes of Chromium(0) and Iron(0) with Tricyclo[4.3.1.01,6]-deca-2,4-diene

✍ Scribed by R. L. Beddoes; P. F. Lindley; O. S. Mills

• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: English
• Weight: 240 KB
• Volume: 9
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.197003041

✦ Synopsis

downfield. Thus on complex formation of (/), additional shielding and deshielding effects occur which can be explained in terms of a diamagnetic ring current in complex (2). We therefore propose the homoaromatic structure (2a) for the complex. Further support for this assignment comes from the fact that tricyclo[4.3.1.0~~~ldeca-2,4-dienetricarbonyliron 1101 (6) [m.p. 49 'C; UV spectrum: maxima 247 ( E = 17500) and 305 (3500) with a shoulder at 390nm (350); in nhexane], whose central atom bonds only with the four iselectrons of the ligand, is shown by its N M R parameters 1111 (cf. Tables 1 and2) and by its UV spectrum"2J to be a normal diene complex. The interatomic distances in (21, especially the distance C-1-C-6 = 1.65 8, (d C-1-C-6 in 2,5-dimethyl-7,7-dicyanonorcaradiene = 1 .SO A 1149, which have recently been determined in an X-ray structure analysis by Mills et a/. [131, may be regarded as further confirmation of the homoaromatic structure (2a) [151.