Acta Crystallographica Section B

Structural Science

Volume 56, Part 2 (April 2000)

research papers

Acta Cryst. (2000). B56, 273-286 [ doi:10.1107/S0108768199013051 ]

Oligosiloxanediols as building blocks for supramolecular chemistry: hydrogen-bonded adducts with amines form supramolecular structures in zero, one and two dimensions

B. O'Leary, T. R. Spalding, G. Ferguson and C. Glidewell

Abstract: The structure of 1,1,3,3,5,5-hexaphenyltrisiloxane-1,5-diol-pyrazine (4/1), (C₃₆H₃₂O₄Si₃)₄·C₄H₄N₂ (1), contains finite centrosymmetric aggregates; the diol units form dimers, by means of O-HO hydrogen bonds, and pairs of such dimers are linked to the pyrazine by means of O-HN hydrogen bonds. In 1,1,3,3,5,5-hexaphenyltrisiloxane-1,5-diol-pyridine (2/3), (C₃₆H₃₂O₄Si₃)₂·(C₅H₅N)₃ (2), the diol units are linked into centrosymmetric pairs by means of disordered O-HO hydrogen bonds: two of the three pyridine molecules are linked to the diol dimer by means of ordered O-HN hydrogen bonds, while the third pyridine unit, which is disordered across a centre of inversion, links the diol dimers into a C₃³(9) chain by means of O-HN and C-HO hydrogen bonds. In 1,1,3,3-tetraphenyldisiloxane-1,3-diol-hexamethylenetetramine (1/1), (C₂₄H₂₂O₃Si₂)·C₆H₁₂N₄ (3), the diol acts as a double donor and the hexamethylenetetramine acts as a double acceptor in ordered O-HN hydrogen bonds and the structure consists of C₂²(10) chains of alternating diol and amine units. In 1,1,3,3-tetraphenyldisiloxane-1,3-diol-2,2'-bipyridyl (1/1), C₂₄H₂₂O₃Si₂·C₁₀H₈N₂ (4), there are two independent diol molecules, both lying across centres of inversion and therefore both containing linear Si-O-Si groups: each diol acts as a double donor of hydrogen bonds and the unique 2,2'-bipyridyl molecule acts as a double acceptor, thus forming C₂²(11) chains of alternating diol and amine units. The structural motif in 1,1,3,3-tetraphenyldisiloxane-1,3-diol-pyrazine (2/1), (C₂₄H₂₂O₃Si₂)₂·C₄H₄N₂ (5), is a chain-of-rings: pairs of diol molecules are linked by O-HO hydrogen bonds into centrosymmetric R₂²(12) dimers and these dimers are linked into C₂²(13) chains by means of O-HN hydrogen bonds to the pyrazine units. 1,1,3,3-Tetraphenyldisiloxane-1,3-diol-pyridine (1/1), C₂₄H₂₂O₃Si₂·C₅H₅N (6), and 1,1,3,3-tetraphenyldisiloxane-1,3-diol-pyrimidine (1/1), C₂₄H₂₂O₃Si₂·C₄H₄N₂ (7), are isomorphous: in each compound the amine unit is disordered across a centre of inversion. The diol molecules form C(6) chains, by means of disordered O-HO hydrogen bonds, and these chains are linked into two-dimensional nets built from R₆⁶(26) rings, by a combination of O-HN and C-HO hydrogen bonds.

Keywords: Oligosiloxanediols; Supramolecular chemistry; Adducts; Hydrogen bonding.


	Structure factor file (CIF format) (722.8 kbytes) Contains datablock sila1

	Structure factor file (CIF format) (416.7 kbytes) Contains datablock sila2

	Structure factor file (CIF format) (315.0 kbytes) Contains datablock sila3

	Structure factor file (CIF format) (324.6 kbytes) Contains datablock 94809

	Structure factor file (CIF format) (254.6 kbytes) Contains datablock sila5

	Structure factor file (CIF format) (142.3 kbytes) Contains datablock sila6

	Structure factor file (CIF format) (141.2 kbytes) Contains datablock sila7

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