Solid State polymerization of diacetylenes 3.* Crystal and molecular structure of 1,4-bis( 1 -oxyl-2,2,6,6-tetramethyl-4-hydroxy-piperidine- 4-yl)butadiyne

Abstract

An X-ray structural study {R = 0.040 for 1871 reflections) of the title Compound has been carried out. Molecules in crystal are pseudocentrosymmetric, the piperidine cycle is in a chair conformation. The N atoms of both paramagnetic centers exhibit, in fact, the same degree of pyramidalization, their displacements from the planes of their bonded atoms being 0.111 and 0.119(2) Ä. In crystal the molecules form two sets of infinite ribbons (along the [112] and [Tl2] directions), which are linked with each other via the O -H... O hydrogen bonds along the [001] direction. Although the packing of diacetylene rod-like groups does not correspond to the conditions of topochemical polymerization of diacetylenes, Compound I polymerizes in crystal. * Part 2 of see Shklover et al., 1990.

Solid State polymerization of diacetylenes 5*. Crystal and molecular stnictiire of 1,6-bis(1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine-4-yl)- hexa-2,4-diyne

“…Jn = 0.111 and 0.119(2) Ä for II (Shklover et al, 1990), whereas a quite different Jn = 0.042(2) Ä value is observed for the N'-atom. It is noteworthy that in spite of the different degree of pyramidalization of the N and N' atoms, the N -O distances are, in fact, the same [1.286 and 1.288 (2) (Baughman, 1974;Wegner, 1979) in crystal I.…”

“…Molecule (I) diflers from the studied earlier l,4-bis-(l-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine-4-yl)butadiyne (II) (Shklover et al, 1990) by the presence of CH2-groups between the diacetylene system and the heterocyclic iminoxyl fragments.…”

Solid State polymerization of diacetylenes 4*. Crystal and molecular structure of l,4-bis(1-oxyl-2,2,6,6-tetrainethyl-∆3-dehydropiperidine-4-yl)butadiyne

“…1. The six-membered heterocycle has a distorted boat conformation: the N and C(5) atoms are displaced in the same direction by 0.214 and 0.740(2) Ä respectively from the mean plane of the other four atoms of the cycle which are coplanar within 0.006(2) Ä. Six-membered saturated iminoxyl heterocycles have as a rule a chair conformation (Shibaeva, 1975) which was found for example in 1,4-bis-(l -oxyl-2,2,6,6-tetramethyl-4-hydroxypiridine-4-yl)butadiyne (II) (Shklover et al, 1990) and l,6-bis(2,2,6,6-tetramethyl-4-hydroxy-l-oxyl-piperidine-4-yl)hexa-2,4-diyne (III) (Shklover et al, 1990). The C(2) = C(3) double bond is the heterocycle I has no effect on the geometry of the paramagnetic > N -O group: the displacement of the N atom from the plane of the three bonded atoms zIn is equal to 0.131(2) Ä, (Fig.…”

“…In the course of systematic studies of the crystal structure-solid State reactivity correlations and in connection with the synthesis of the ferromagnetic * Part 3 see Shklover et al, 1990. ** Dr. V. E. Shklover, Institute of Organoelement Compounds, 28 Vavilov St., Moscow B-334, U.S.S.R.…”