Structural characterisation of beryllium phthalocyaninato(2-) complexes axially ligated by O- and N-donating ligands Ryszard Kubiak, Jan Janczak * Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw, Poland article info Article history: Received 6 May 2009 Received in revised form 24 June 2009 Accepted 25 June 2009 Available online 30 June 2009 Keywords: Phthalocyanines Beryllium Coordination complexes Crystal structure abstract Recrystallisation of beryllium phthalocyanine (BePc) in water-free 2-picoline (2-Mepy) and in water-free 3-picoline (3-Mepy) yields to obtain the BePc(2-Mepy)2-Mepy (I) and BePc(3-Mepy)3-Mepy (II), while recrystallisation in wet (containing water) 2- and 3-picolines isomers yields to formation of the aquabe- ryllium phthalocyaninato(2-) complexes that crystallise with solvent molecule, 2-picoline (Ia) or 3-pico- line (IIa). Single crystal analyses show 4 + 1 coordination of the Be(II) ion in these complexes. It is equatorially ligated by the four N-isoindole atoms of Pc macrocycle and axially by the N-ring atom of 3-Mepy (II) or by O atom of water in Ia and IIa. Interaction of the central Be(II) ion of the BePc with axial N or O donating ligands leads to the saucer-shape form of Pc macrocycle and deviates the Be(II) from the N 4 -isoindole plane by 0.31 Å. Thus, p–p interaction between the p-clouds of Pc aromatic macrorings in II and additionally the O–HN hydrogen bonds in Ia and IIa are the forces responsible for the stabilisa- tion of the molecular arrangement in the crystals. Thermogravimetric analyses confirm the compositions of the complexes. Ó 2009 Elsevier B.V. All rights reserved. 1. Introduction Beryllium phthalocyanine (BePc) belongs to the monometall- ophthalocyanines family pigments, known since the early papers of Linstead and Robertson [1,2]. However, the details of its crystal structure were reported relatively recently [3]. For a broad range of applications it is necessary to modify the phthalocyanine core, for instance, by axial coordination of the central atom by various O- and N-donating ligands. In this respect, among the phthalocya- nines with the metals of the main group II, the magnesium phtha- locyanine and its monoaxially (4 + 1) and biaxially (4 + 2) ligated complexes were extensively studied in our laboratory [4–11]. However, little is known about the axially ligated beryllium phthalocyanine derivatives. Recently the beryllium phthalocyanine complexes with axially coordinated water molecule [3] or ring nitrogen atom of 4-picoline (4-Mepy) have been characterised [12]. Generally, the M(II) in the MPc complexes may be biaxially or monoaxially coordinated by the O- or N-donating solvents. It is however, well experienced that the additive coordinative features of the metal ions in MPc’s may differ quite significantly. Monoax- ially ligated MPcL (L = O- or N-donating ligands) complexes are promising materials for modern technology as materials for catal- ysis, sensors and non-linear optics [13–16]. In this context, the BePc additive complexes may be attractive and interesting materi- als, because the peculiar property of beryllium seems to be its strong tendency to form monoaxial BePc additive complexes with the lone electron pair of the O- and N-donative ligand molecules. Quite recently we have investigated the competition effects be- tween the 4-picoline (4-Mepy) and water molecules to formation of axially ligated BePc derivatives [17]. In this work, we investigate the solid state products of BePc recrystallisation in water-free as well as in wet 2-picoline and 3-picoline. 2. Experimental 2.1. Synthesis and characterisation The reactants, i.e. metallic beryllium silvers (99.9%), 1,2-dicya- nobenzene (melting point 139–141 °C), 2-picoline and 3-picoline were purchased from Sigma–Aldrich Co. Routinely the crystalline phases obtained were checked on a X-ray powder diffractometer equipped with a linear PSD detector [18] and on an energy disper- sive spectrometer for their composition. Crystalline BePc was ob- tained as described previously [3]. 2.1.1. Recrystallisation of BePc in 2-picoline (2-Mepy) and in 3-picoline (3-Mepy), both water-free For the recrystallisation in dry 2-Mepy and 3-Mepy the freshly synthesised BePc in crystalline form was used. The BePc (0.5 g) was inserted in a glass ampoule and covered with ca. 10 mL dry 2-Mepy (I) or dry 3-Mepy (II). The samples were than degassed and sealed 0022-2860/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.molstruc.2009.06.036 * Corresponding author. E-mail address: j.janczak@int.pan.wroc.pl (J. Janczak). Journal of Molecular Structure 935 (2009) 53–59 Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc