An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The title 1,2-diol derivative, C10H12O2, crystallizes with two independent but closely similar mol­ecules in the asymmetric unit. Only two of the four OH groups are involved in classical hydrogen bonding; the mol­ecules thereby associate to form chains parallel to the short c axis. The other two OH groups are involved in O—H⋯(C≡C) systems. Additionally, three of the four C≡C—H groups act as donors in C—H⋯O inter­actions. The 1,4-diol derivative crystallizes with two independent half-mol­ecules of the diol (each associated with an inversion centre) and one water mol­ecule in the asymmetric unit, C12H16O2·H2O. Both OH groups and one water H atom act as classical hydrogen-bond donors, leading to layers parallel to the ac plane. The second water H atom is involved in a three-centre contact to two C≡C bonds. One acetyl­enic H atom makes a very short `weak' hydrogen bond to a hydr­oxy O atom, and the other is part of a three-centre system in which the acceptors are a hydroxy O atom and a C≡C bond.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The title compound, C 12 H 22 Br 2 , displays crystallographic inversion symmetry. Bond lengths C=C = 1.352 (4) Å and C sp 2 —C sp 3 = 1.574 (3) Å are interpreted as symptoms of steric overcrowding. Molecules are linked into chains parallel to [101] by Br...Br interactions of 3.4275 (9) Å.

The title compound, C11H20O, shows a wide Me3C-C=C angle of 129.60 (14)degrees. Molecules associate into zigzag chains parallel to [101] via a hydrogen bond H-methyl center dot center dot center dot O-ketone.

In the title compound, C22H34Si2, the two independent molecules are closely similar. The reduced rings show a flattened twist conformation. Several features of [2.2]paracyclophane strain (e. g. lengthened bridge bonds) are apparent; an exception is furnished by the normal sp(2) values of the angles at the bridgehead atoms of the reduced rings.

In the title compound, 2C(30)H(18)center dot 3C(12)H(4)N(4), the asymmetric unit consists of half a formula unit ( one quinodimethane molecule displays inversion symmetry). There is no ring stacking; instead, the residues associate by weak C - H center dot center dot center dot N contacts in planes parallel to (2 (11) over bar).

In the title compound, C19H30Si, the double bonds are essentially localized. The central ring and its substituents, including the triple-bond system, are coplanar, with the Si atom lying 0.148 (2) Angstrom out of the plane. The packing involves herring-bone layers parallel to the ab plane.

The title compound, C8H8Br4, displays crystallographic inversion symmetry. The packing involves inter­penetrating corrugated layers built up via Br⋯Br and Br⋯π contacts.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

In preceding papers, cinnamophanes 1a-d (two cinnamic ester units locked in a [2.2]paracyclophane skeleton) were described. In particular, the pseudo-gem isomer 1a was shown to produce in solution an intramolecular cyclobutane photocycloadduct with stereospecificity and very high efficiency, following the topochemical rule observed in the solid state. Here are reported the synthesis and X-ray structure determination of their vinylogs 5a-d. The photoreactivity of the pseudo-gem isomer 5a was especially investigated in order to examine whether the same specificity would be maintained for the longer dienic substituents. It was found that, depending on the irradiation wavelengths, different bicyclic (8) and tetracyclic (9 and 10) intramolecular photocycloadducts (ladderanes) were produced, but with reduced efficiency as compared to that of 1a. The pseudo-ortho- and pseudo-para isomers 5b and 5d form the oxetenes 11 and 12, respectively, on irradiation. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).

The title compound, C28H52Si4, crystallizes in the uncommon space group I4(1)22 with 222 symmetry. Despite the reduction of the rings, several features of [2.2]paracyclophane strain are still apparent.

In the title compound, C30H18, the fluorene moiety displays normal dimensions, such as a narrow ring angle of 105.3( 3)degrees at the 9-position, the atom bearing the exocyclic double bond. The phenyl rings subtend angles of 14.8( 2) and 3.9 ( 2)degrees to the fluorene plane. Molecules are stacked parallel to the short c axis of 4.001 (1) angstrom.

In the title compound [systematic name: 1,3-di-tert-butyl-5-(3-phenylprop-2-ynylidene)cyclopenta-1,3-diene], C22H26, the rings subtend an interplanar angle of 15.7 (1)°. The triple bond length is 1.205 (3) Å.

In the title compound, C24H28Si2, the interplanar angle between the groups on the ends of the central double bond is 7.3 (4)degrees and the length of this bond is 1.361 (3) Angstrom. The molecules form layers parallel to ((2) over bar 12).