3‐Chloro‐1,2,3,4‐tetraphenylcyclobutenyl‐Ennea‐chloro‐μ‐Oxo‐di‐Niobat(V),[C₄Cl(Ph)₄]^⊕[Nb₂OCl₉]^⊖ Synthese und Kristallstruktur

Abstract

Die Titelverbindung bildet sich in Form dunkelgrüner Kristalle in Dichlormethan im Einschrittverfahren aus Diphenylacetylen, Niobpentachlorid und Nioboxidtrichlorid. Der neue Komplex wird durch das IR‐Spektrum und durch eine Röntgenstrukturbestimmung charakterisiert. Die Verbindung kristallisiert triklin in der Raumgruppe P1 mit zwei Formeleinheiten pro Elementarzelle (2253 unabhängige, beobachtete Reflexe, R = 4,7%). Die Gitterabmessungen sind: a = 1199, b = 1034, c = 1453 pm; α = 87,0°, β = 108,6°, γ = 96,6°. Das Cyclobutenylkation bildet einen nahezu ebenen C4‐Ring mit zwei Paaren benachbarter CC‐Bindungen mit 139 und 153 pm. Das [Nb2OCl9]⊖‐Anion weist eine fast gestreckte NbONb‐Achse von 174° auf bei NbO‐Bindungsabständen von 176 bzw. 208 pm. Es ist über asymmetrische Chlorobrücken mit NbCl‐Abständen von 248 bzw. 270 pm zu einem zentrosymmetrischen Dimeren verknüpft.

Investigations on non-classical silylium ions leading to a cyclobutenyl cation

“…Of these, the protonated cations [R 4 C 4 –H] + with R = H, Me, Ph were only characterized by NMR at –40 to –70 °C,27 while with R = t Bu they were shown to be isolable with a large variety of anions, like Br – or [SbF 6 ] – 26. Also the chlorinated and hydroxylated cations [Ph 4 C 4 –Cl] + and [ t Bu 4 C 4 –OH] + and the neutral [Me 4 C 4 –AlCl 3 ] were shown to be stable at r.t. and could be isolated 23,24,26,29…”

“…This cation can be seen as a silylated cyclobutadiene and is closely related to the already known homoaromatic [R 4 C 4 –H] + , [R 4 C 4 –Cl] + , [ t Bu 4 C 4 –OH] + and the neutral [R 4 C 4 –AlX 3 ] (R = H, Me, t Bu, Ph; X = Cl, Br). 23 – 29 Of these, the protonated cations [R 4 C 4 –H] + with R = H, Me, Ph were only characterized by NMR at –40 to –70 °C, 27 while with R = t Bu they were shown to be isolable with a large variety of anions, like Br – or [SbF 6 ] – . 26 Also the chlorinated and hydroxylated cations [Ph 4 C 4 –Cl] + and [ t Bu 4 C 4 –OH] + and the neutral [Me 4 C 4 –AlCl 3 ] were shown to be stable at r.t. and could be isolated.…”

“… 26 Also the chlorinated and hydroxylated cations [Ph 4 C 4 –Cl] + and [ t Bu 4 C 4 –OH] + and the neutral [Me 4 C 4 –AlCl 3 ] were shown to be stable at r.t. and could be isolated. 23 , 24 , 26 , 29 …”

Crystal structures of [N(C4H9)4][NbCl4OAlCl3] and [N(C3H7)4][NbCl6]

“…Selected bond lengths and angles are given in Table 3. The short Nb± ±O bond corresponds to a bond order of 2.5 [5]. 1 [7].…”

“…The educts [N(C 4 H 9 ) 4 ]Cl, NbCl 5 6 ] 2 were mixed in equimolar amounts in a glove box. The educts [N(C 4 H 9 ) 4 ]Cl, NbCl 5 6 ] 2 were mixed in equimolar amounts in a glove box.…”