research papers Acta Cryst. (2015). C71, 491–498 http://dx.doi.org/10.1107/S2053229615009857 491 Received 18 April 2015 Accepted 21 May 2015 Edited by R. F. Baggio, Comisio ´ n Nacional de Energı ´a Ato ´ mica, Argentina Keywords: triphenylcyclopentadiene synthesis; crystal structure; hydrogen bonding; diaster- eomers; NMR analysis; cyclohexanol. CCDC references: 1402371; 1402370 Supporting information: this article has supporting information at journals.iucr.org/c A structural study of (1RS,2SR,3RS,4SR,5RS)-2,4- dibenzoyl-1,3,5-triphenylcyclohexan-1-ol chloro- form hemisolvate and (1RS,2SR,3RS,4SR,5RS)-2,4- dibenzoyl-1-phenyl-3,5-bis(2-methoxyphenyl)- cyclohexan-1-ol Mikhail E. Minyaev, a * Dmitrii M. Roitershtein, a Ilya E. Nifant’ev, a Ivan V. Ananyev, b Tatyana V. Minyaeva c and Timofey A. Mikhaylyev d a A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky prospect, 119991 Moscow, Russian Federation, b A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova Str., 117813 Moscow, Russian Federation, c High school ‘Moomintroll’, 1 Volokolamskoye shosse, Moscow, Russian Federation, and d The Higher Chemical College of Russian Academy of Sciences, 9 Miusskaya square, 125047 Moscow, Russian Federation. *Correspondence e-mail: mminyaev@mail.ru14023711402370 (1RS,2SR,3RS,4SR,5RS)-2,4-Dibenzoyl-1,3,5-triphenylcyclohexan-1-ol or (4-hy- droxy-2,4,6-triphenylcyclohexane-1,3-diyl)bis(phenylmethanone), C 38 H 32 O 3 , (1), is formed as a by-product in the NaOH-catalyzed synthesis of 1,3,5-triphenyl- pentane-1,5-dione from acetophenone and benzaldehyde. Single crystals of the chloroform hemisolvate, C 38 H 32 O 3 0.5CHCl 3 , were grown from chloroform. The structure has triclinic (P 1) symmetry. One diastereomer [as a pair of (1RS,2SR,3RS,4SR,5RS)-enantiomers] of (1) has been found in the crystal structure and confirmed by NMR studies. The dichoromethane hemisolvate has been reported previously [Zhang et al. (2007). Acta Cryst. E63, o4652]. (1RS,2SR,3RS,4SR,5RS)-2,4-Dibenzoyl-3,5-bis(2-methoxyphenyl)-1-phenylcyclo- hexan-1-ol or [4-hydroxy-2,6-bis(2-methoxyphenyl)-4-phenylcyclohexane-1,3- diyl]bis(phenylmethanone), C 40 H 36 O 5 , (2), is also formed as a by-product, under the same conditions, from acetophenone and 2-methoxybenzaldehyde. Crystals of (2) have been grown from chloroform. The structure has orthorhombic (Pca2 1 ) symmetry. A diastereomer of (2) possesses the same configuration as (1). In both structures, the cyclohexane ring adopts a chair conformation with all bulky groups (benzoyl, phenyl and 2-methoxyphenyl) in equatorial positions. The molecules of (1) and (2) both display one intra- molecular O—HO hydrogen bond. 1. Introduction Cyclopentadienyl ligands are still among the most used ligands in transition-metal organometallic chemistry. However, crystal structures of triaryl-substituted cyclopentadienyl complexes of d- and especially f-metals have been less well studied. The Cambridge Structural Database (CSD, Version 5.36 with updates; Groom & Allen, 2014) includes 15 crystal structures of d-metal complexes bearing triarylcyclopentadienyl ligands, namely, four complexes with the 1,2,4-triphenylcyclopenta- dienyl ligand, four complexes with the 1,2,4-tris(pentafluoro- phenyl)cyclopentadienyl ligand and seven complexes with other 1,2,4-triarylcyclopentadienyl ligands. The number of f-metal crystal structures with triarylcyclopentadienyl ligands is limited to only three structures, all of which have the 1,2,4- triphenylcyclopentadienyl anion [CSD refcodes JOKJAV (Visseaux et al., 2008), and OFUGUT and OFUHAA ISSN 2053-2296 # 2015 International Union of Crystallography