1772 https://doi.org/10.1107/S2056989018015645 Acta Cryst. (2018). E74, 1772–1777 research communications Received 28 September 2018 Accepted 5 November 2018 Edited by E. V. Boldyreva, Russian Academy of Sciences, Russia Keywords: crystal structure; charge transfer; Hirshfeld surface; hydrogen bonding. CCDC references: 1877153; 1877152; 1877151; 1877150 Supporting information: this article has supporting information at journals.iucr.org/e Binary charge-transfer complexes using pyromellitic acid dianhydride featuring C—HO hydrogen bonds Tania N. Hill and Andreas Lemmerer* Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag, PO WITS, 2050, Johannesburg, South Africa. *Correspondence e-mail: andreas.lemmerer@wits.ac.za Four binary charge-transfer complexes were made using pyromellitic acid dianhydride (pmda), those being pmda–naphthalene (1/1), C 10 H 2 O 6 C 10 H 8 , (I), pmda–fluoranthene (1/1), C 10 H 2 O 6 C 16 H 10 , (II), pmda–9-methylanthracene (1/1), C 10 H 2 O 6 C 15 H 12 , (III), and pmda–ethyl anthracene-9-carboxylate (1/2), C 10 H 2 O 6 2C 17 H 12 O 3 , (IV). All charge-transfer complexes show alternating donor and acceptor stacks, which have weak C—HO hydrogen bonds connecting the donor and acceptor molecules. In addition, complex (I) has Z 0 = 1/2, complex (II) has a Z 0 = 2 and complex (IV) has half molecule of pyromellitic acid dianhydride in the asymmetric unit. 1. Chemical context Crystal engineering, the conception and synthesis of molecular solid state structures, is fundamentally based upon the discernment and subsequent exploitation of intermolecular interactions. Consequently, non-covalent bonding interactions are primarily used to achieve the organization of molecules and ions in the solid state in order to produce materials with desired properties. and this understanding using a variety of intermolecular interactions is at the very heart of crystal engineering. Recently, it has been shown that one can synthesize supramolecular assemblies that contain anywhere from three to six different molecular moieties (Paul et al., 2018). Supramolecular synthesis chiefly uses the hydrogen- bond interaction as the most directional of the known inter- molecular interactions (Aakero ¨y & Beatty, 2001). An equally important interaction is that of charge transfer (CT) between an electron-rich -system (donor) and an electron-poor - system (acceptor) (Herbstein, 2005). Classic donor molecules (polycyclic aromatic hydrocarbons) generally have an elec- tron-rich -system. On the other hand, aromatic hydrocarbons with strongly polarizing groups, such as 1,3,5-trinitrobenzene (TNB), have an electron-poor -system and are classified as the acceptor molecule (Hill et al., 2018a,b). Another common acceptor molecule is pyromellitic acid dianhydride (pmda), which has electron-withdrawing O atoms of the carboxylic acid dianhydride groups. (pmda)(pyrene) complexes have been investigated for order–disorder transitions as a function of temperature using infrared and Raman spectroscopy (Isaac et al., 2018), (pmda)(naphthalene) has been studied via Raman spectroscopy for having orientational disorder (Macfarlane & Ushioda, 1977), disorder in (pmda)(perylene) via computer simulation (Boeyens & Levendis, 1986), and photoconductivity and magentoconductance in pmda- ISSN 2056-9890