The term originally applied to compounds having two p-phenylene groups held face to face by –[CH2]n bridges. It now designates compounds having (i) @M03695@, or assemblies of @M03695@, and (ii) atoms and/or saturated or unsaturated chains as alternate components of a large ring. E.g. [2.2](1,4)(1,4)cyclophane [or 1(1,4),4(1,4)-dibenzenacyclohexaphane].
Many chemists include in this class any bridged aromatic system, irrespective of the @A00512@ positions of the @B00736@.
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1330 [Terms] [Paper]