Synthesis and characterization of germa[n]pericyclynes

Abstract

The synthesis and characterization of novel pericyclynes comprising germanium atoms and acetylenes, germa[n]pericyclynes, are described. The prepared germa[4]-, [6]-, and [8]pericyclynes were compared by (13)C NMR spectroscopy, X-ray crystallography, cyclic voltammetry, UV-visible spectroscopy, fluorescence emission spectroscopy, Raman spectroscopy, and density functional theory calculation analyses.

Stepwise synthesis and characterization of germa[4], [5], [8], and [10]pericyclynes

“…[5]Pericyclynes 6a-b displayed envelope conformations, while [4]pericyclyne 4a was previously found to be planar. 9 The smallest C-Ge-C angles of 6a-b were comparable to 4a (4a: 103.66(10)°, 9 6a: 104.1(3)°, 6b: 103.58(18)°), while the largest C-Ge-C angles were 107.6(3)°for 6a and 109.01(19)°for 6b, respectively. The Ge-CuC angles were found to vary between 170.2(8)°and 178.6( 6)°(6a), and between 166.0(4)°and 176.8(4)°(6b).…”

“…106.1°and 177.2°(Me-sila [5]) 4f ), and were not bent to the extent of 4a (103.8°and 172.3°). In contrast, [10]pericyclynes 7a-b were present in zigzag forms, 9 with 7a displaying intramolecular π-π interactions between the phenyl rings present in its cavity. From X-ray data, the estimated distance between phenyl rings in the cavity of 7a was approximately 3.5-3.8 Å with full ring overlap while that of 5a 9 was 3.5 Å with only partial overlap.…”

“…We first performed the stepwise synthesis of germapericyclynes from diethynylgermanes 1a-b. 9 To monoanions of 1a-b, generated by the addition of n-butyllithium, was added 0.5 eq. of the appropriate germanium dichloride to give trimeric compounds 2a-b (Scheme 1).…”

“…1). 9 It was demonstrated that such compounds were efficient building blocks for incorporation into functional materials and polymers. However, our previous one-step synthesis unselectively afforded [4], [6], and [8]pericyclynes in low yields.…”

Hydrosilylation and Hydrogermylation of CO2 and CS2 by Al and Ga Functionalized Silanes and Germanes – Cooperative Reactivity with Formation of Silyl Formates and Disilylacetals

“…Only the most intensive masses are given, the isotopic patterns were in agreement with the calculated ones. Synthesis of iPr 2 GeCl 2 : iPr 2 GeCl 2 was synthesized according to a literature procedure, [42] but work-up by vacuum distillation instead of preparative HPLC improved the yield from 19 to 73 %. iPrMgCl (40.0 mL, 80.0 mmol, 2 M in THF) was added dropwise over a period of 2 h to a solution of GeCl 4 (4.55 mL, 8.65 g, 40.3 mmol) in THF (100 mL) at -78°C.…”