Nonapentafulvalene by Oxidative Coupling of Cyclononatetraenide and Cyclopentadienide

Abstract

of the anion closely resembles that of [Moz05(o-benzened i~l a t e )~]~~~'~ and of [MoZO5(3,5-di-tert-1,2-benzenedioland possesses two cis-dioxomolybdenum(v1) centers bridged by one pz-oxido-and two pz-O-2-sulfidophenolate ligands. The last-mentioned bridges are asymmetr!c and involve Mo-0 distances of 2.117(2) and 2.482(2) A. The Mo atom has a very distorted octahedral environment of five 0 and one S donor atoms, with the largest and the smallest bond angles being 02Mo04'= 167.4(1)" and 03Mo04'= 67.q l ) O , respectively. The UV/VIS spectrum of [PPh4]Z[Moz05(SC6H40)z] contains two bands of a comparable intensity with A,,,,, = 400 and 350 nm and an ab-

The Fulvalenes

“…[27] Because each of the rings contain 4n electrons the oxidative coupling approach to the parent, as demonstrated for the pentafulvalenes (Scheme 1), is applicable here. Escher and Neuenschwander showed that such coupling can be brought about, but use of five molar equivalents of sodium cyclopentadienide with one of 157 in the presence of 6.6 mol.…”

“…equivalents of CuCl 2 in THF at -50°C results in the dihydro derivatives 165 and 14 (Scheme 36) with only traces of the [9.9] coupled molecule. [27,220] Scheme 36.…”

“…[5,21] The appearance of derivatives of pentaheptafulvalene [22] (6) and triapentafulvalene [23] (4) date from 1952 and 1965, respectively. Heptafulvalene 7 appeared between these dates as an almost black crystalline compound of limited stability, [17,18,24] with triahepta-9, [25] trianona-10 [26] pentanona-11, [27] and nona-12 fulvalenes, [28] emerging over a 16 year period from the early 1970s; attempts to prepare heptanonafulvalene [29] (8) give valence bond isomers, while the triafulvalenes, cf. 3, remained unknown until our very recent evidence for a reactive benzannulated derivative.…”