Synthesis and Structural Study of [5.5](2,6)Pyridinophanes and -cyclophanes Containing Silylene Units

Abstract

Four [5.5](2,6)pyridinophanes and -cyclophanes containing silylene units (2a,b, 3a,b) have been prepared by reacting dichlorosilanes with pyridine- or benzenedimethanol. X-ray structures of compounds 2a, 2 b, and 3a have been determined. The diphenylsilylene pyridinophane 2b and dimethylsilylene cyclophane 3a were found to adopt an anti conformation in the solid state. In contrast, the dimethylsilylene pyridinophane 2a exhibits a syn arrangement. The conformational preference of these cyclophanes without the influence of the packing energy was analyzed by molecular mechanics calculations. The results show that all the derivatives preferentially adopt a syn conformation, whereas the anti geometry found in the solid state for 2b and 3a does not play a significant role in the conformational equilibrium at room temperature.

Siloxane Coordination Revisited: Si−O Bond Character, Reactivity and Magnificent Molecular Shapes

“…Hence, an unsupported bite angle of the crown‐type macrocycle reduces the cation binding ability significantly. The experimental findings are supported by the fact that a series of ring contracted and sila‐crown ethers bearing several −CH 2 −CH 2 −O− as well as one‐ or two −SiR 2 −O− units have been described in literature, [146−154] but, no coordination compounds have been isolated and crystallographically characterized to date.…”

Formation of a silicon-containing macrocycle with a pyridoxalimine Schiff base ligand

“…The O 2 Si(Ph) 2 group is a common structural motif. Some macrocycles with a similar distorted tetrahedral coordination environment at the Si atom have been described previously (Cragg et al, 1991;Rezzonico et al, 1998;Gó mez & Farfá n, 1999). The rather large bond angles at oxygen (Table 1) are explained by the ionic character of the Si-O bonds (Gillespie & Johnson, 1997).…”

Synthesis and Сharacterization of Phosphamacrocycles on the Basis of 2,7-Dihydroxynaphthalene

“…[1,2] Нафталиновые производные широко применяются в качестве ароматических блоков в циклофановых структурах. [3][4][5][6][7][8] Кроме того, сам нафталин и его производные (особенно гидроксипроизводные) являются хорошими акцепторами малых молекул, в частности, кислорода, [9][10][11] удобными объектами для изучения процессов таутомерии, [12] хорошо участвуют DOI: 10.6060/mhc2011. 4.07 Phosphamacrocycles on the Basis of 2,7-Dihydroxynaphthalene в образовании комплексов с переносом заряда.…”