Darstellung und Molekülstruktur von 1,3‐Diaza‐2,4‐disilacyclobutanen

Abstract

Lithio‐aminofluorsilane werden in der Reaktion von Aminofluorsilanen mit Butyllithium erhalten. Die thermische LiF‐Abspaltung aus Lithio‐aminofluorsilanen ist ein einfacher Syntheseweg für viergliedrige Silicium‐Stickstoff‐Ringe. Röntgenstrukturuntersuchungen wurden von 1,3‐Bis(3,5‐dimethylphenyl)‐2,2,4,4‐tetramethyl‐1,3‐diaza‐2,4‐disilacyclobutan und von 2,4‐Di‐tert.‐butyl‐2,4‐difluor‐1,3‐bis(2,4,6‐trimethylphenyl)‐1,3‐diaza‐2,4‐disiacyclobutan durchgeführt.

1,3-Bis(2,6-diisopropylphenyl)-2,2,4,4-tetramethyl-1,3-diaza-2,4-disilacyclobutane

“…;t %s (13 The Si--N distances are 1.748 (1) and 1.744 (1) A, the Si--N--Si angle is 93.72(5) ° and the N--Si-N angle is 86.28 (5) °. A similar molecular geometry has been observed in related compounds with Si2N2 rings planar within experimental° error, Si--N bond lengths in the range 1.73-1.75A, SimN--Si bond angles of 93-95 ° and N--Si--N angles of 85-87 ° (Bihatsi, Hencsei & Parkanyi, 1981;Clegg, Klingebiel, Sheldrick & Vater, 1981;Szollosy, Parkanyi, Bihatsi & Hencsei, 1983;Parkanyi, Argay, Hencsei & Nagy, 1976;Parkanyi, Bihatsi & Hencsei, 1994). Owing to the steric requirements of the isopropyl groups in the ortho position, the phenyl groups are forced to lie in a plane perpendicular to the cyclodisilazane ring [dihedral angle 89.12 (9)°].…”

Structure of 1,3-di-tert-butyl-2,2,4,4-tetraisopropylcyclodisilazane, C20H46N2Si2

“…1. As in almost all cases of symmetrically substituted cyclodisilazanes (Clegg, Hesse, Klingebiel, Sheldrick & Skoda, 1980;Clegg, Klingebiel, Sheldrick & Vater, 1981;Wheatley, 1962), the molecule has crystallographic inversion symmetry.…”

The crystal structure of 2-chloro-1,3-bis(2,4,6-trimethylphenyl)-4,4-dimethyl-1,3,2λ3,4-diazaphosphasiletidine

“…The unusually acute N1-Si1-N2 angle in the title compound is associated with Si-N distances of 1.7436(17) Å (Si1-N1) and 1.7445(17) Å (Si1-N2). The latter are remarkably longer than the value reported for a Si-N single bond (1.724(4) Å [13]), but correspond to those in related cyclodisilazanes [14][15][16][17][18][19][20][21][22]. Consequently, the P-N bonds are shorter than expected for a single bond (1.6857(17) Å (P1-N1) and 1.6854(17) Å (P1-N2) vs. 1.704(4) Å [13]).…”