Synthesis and crystal structure of a germanium(II) calix[6]arene containing unusual diamidosilyl ether groups

• Published in: Polyhedron 2008-05, Vol.27 (7), p.1841-1847
• Main Authors: Wetherby, Anthony E., Rheingold, Arnold L., Feasley, Christa L., Weinert, Charles S.
• Format: Article
• Language: English
• Subjects: Calixarenes; Germanium; Macrocycles; Silyl amide; Silyl ether; X-ray crystal structure
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2008.02.027

The reaction of Ge[N(SiMe 3) 2] 2 with calix[6]arene generates a germanium(II) macrocyclic product where the six phenolic oxygen atoms are incorporated into either a Ge 2NO rhombus, a –OSiMe 3 silyl ether group, or two unprecedented –OSi(H)(NH 2) 2 groups. This species has been characterized by X-ray crystallography and multinuclear ( 1H, 13C, and 29Si) NMR spectroscopy. The reaction of Ge[N(SiMe 3) 2] 2 with calix[6]arene furnishes a novel macrocyclic product having two divalent germanium atoms incorporated into a Ge 2NO rhombus which contains a μ 2-oxygen atom and a μ 2-NH 2 group. The crystal structure of the product indicates the presence of a conformationally rigid molecule where three of the six oxygen atoms of the calix[6]arene are bound to the germanium atoms while the remaining three have been converted into –OSiMe 3 or unusual –OSi(H)(NH 2) 2 groups. Spectral ( 1H, 13C, and 29Si NMR) data in solution are consistent with the solid-state structure and indicate the germanium calix[6]arene retains its structure in solution.