Original scientific paper

Chemistry of 1,3-Dioxepins. XIV.1 Structural Studies of 4,7-Dihydro-(4,7-dihydro-1,3-dioxepin-2-yl)-1,3-dioxepin and Their Metal Complexes

Dijana Matak-Vinković ; Laboratory of General and Inorganic Chemistry, Faculty of Science, Ulica kralja Zvonimira 8, 10000 Zagreb, Croatia
Mladen Vinković ; PLIVA-Research Institute, Prilaz baruna Filipovića 25, 10000 Zagreb, Croatia
Miljenko Dumić ; PLIVA-Research Institute, Prilaz baruna Filipovića 25, 10000 Zagreb, Croatia

Abstract

The coordination properties and conformational behaviour of 4,7- dihydro-(4,7-dihydro-1,3-dioxepin-2-yl)-1,3-dioxepin 1, bis-(1,3-dioxepin), or C10H14O4 have been investigated. The crystal and molecular structures of bis-(1,3-dioxepin) (1), bis-(1,3-dioxepin) lithiumperchlorate (2:1) (2) and bis-(1,3-dioxepin) sodium-perchlorate (1:1) (3) complexes, as well as bis-(1,3-dioxepin) hexsaaquamagnesiumperchlorate (3:1) chlatrate (4), have been determined by X-ray diffraction. The molecule of bis-(1,3-dioxepin) is a bidentate ligand in mononuclear lithium complex 2, in contrast to its bridging mode in 2D polymeric sodium complex 3. The coordination environment around lithium in 2 is distorted octahedral with C2 symmetry, while around sodium in 3 it is quasi-pentagonal bipyramidal. Out of four possible conformations of bis-(1,3-dioxepin) molecule, twist-boattwist- boat centrosymmetric (tb-tb-c), twist-boat-twist-boat non-centrosymmetric (tb-tb), twist-boat-chair (tb-ch) and chair-chair (ch-ch), three have been found in the investigated crystal structures: ch-ch in 1, tb-tb in 2 and tb-tb-c in 3 and 4.

Keywords

X-ray; 1,3-dioxepin; conformation

Hrčak ID:

132236

URI

https://hrcak.srce.hr/132236

Publication date:

1.9.1999.

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