Reactivity of the HoPc 2 I in the acetylacetone–water system Jan Janczak ⇑ , Ryszard Kubiak Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, Okólna 2 str., 50-950 Wrocław, Poland article info Article history: Received 26 May 2014 Accepted 16 July 2014 Available online 23 July 2014 Keywords: Holmium phthalocyanine Acetylacetone Holmium acetate polymers Open phthalocyanine Crystal structure abstract Reactivity of holmium diphthalocyanine with iodide HoPc 2 I in the acetylacetone/water system has been investigated. Depending on the water quantity in the system the solvothermal reaction of HoPc 2 I with acacH/water leads to formation of four different compounds. All these four compounds were obtained in the crystalline form. In equilibrium proportion of HoPc 2 I to water (molar proportion of 1:1) in excess of acacH the unique complex of [Ho(oPc)(acac)(OAc)]I0.5(CH 3 COCH 3 )–(1) has been obtained. The neutral open phthalocyanine chelate ligand (oPc) is formed from phthalocyaninate ligand in sequence of numerous processes. The oPc chelate ligand shows alternate single and double bonds due to presence of imine bridge (NH). The imine bridge breaks the p-delocalisation within the whole oPc chelate ligand. The sequence of single and double bonds in the oPc ligand has been confirmed by DFT calculations. Increasing of water quantity in the reacting system leads to formation of three different holmium acetates: anhydrous holmium acetate Ho(CH 3 COO) 3 – 2, bis(holmiumacetate) monohydrate [Ho (CH 3 COO) 3 ] 2 H 2 O– 3 and bis[holmium(diacetate)(triaqua)iodide] monohydrate [Ho(CH 3 COO) 2 (H 2 O) 3 I] 2  H 2 O– 4. These three holmium acetates differ in the amount of water and have different structures. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Metallophthalocyanines (MPc’s) are very important compounds known and utilised since early years of the last century at industry as pigments and dyes [1] and are still attractive for modern tech- nology and medicine owing to their unique physico-chemical properties [2,3]. The utility of MPc complexes is limited by their relatively low solubility in the most organic solvents. The solubility of MPcs can be enhanced by substitution of the H atoms of Pc macrocycle or/and by ligation an additional ligand to the metal centre of MPcs. Both ways of modification of MPc’s lead to improvement of their solubility, due to decreasing of the p–p inter- actions between the Pc macrocycles as well as lowering their aggregation in solution. Metallophthalocyanines due to strong absorption in the red region of visible radiation and high triplet quantum yield and long lifetimes, are intensively studied as poten- tial agents in photodynamic therapy [4,5]. Intensive works are directed toward synthesis and characterisation of the lantha- nide(III) phthalocyanines, which are especially promising as semi- conducting, electrochromic and magnetic materials [6]. In the recent years the metallophthalocyanines found also applications in CD/ROM, CD/Rs, CD/RW, as blue and green colors in LCDs, as photoconductor in laser printers as p-conductor and absorber in organic solar cells [7,8]. Metallophthalocyanine complexes are also intensively investigated as efficient catalysts in homogenous and heterogenous catalysis in many reactions like as oxidation of alkanes, olefins, alcohols, aromatic CAH bonds and the transforma- tion of the cyano group into amide group [9]. The metal complexes of phthalocyanines are suitable catalysts for clean catalytic oxida- tion as well as for other reactions and keep a great promise for the future [10]. It has been well experienced that the features of MPc’s may be tuned by their annealing in various solvents and halogen vapours. In the result of such processing the MPc’s undergo not only recrys- tallisation and/or purification, but they may interact with the sol- vent molecules containing the O- or N-donating atoms, forming axially ligated metallophthalocyanines, or with halogen forming doped or ligated metallophthalocyanines. Numerous such results have been reported, for example the works concerning the struc- tural characterisation of the products of zinc, cobalt and iron phthalocyaninate complexes thermally processed with pyrazine [11]. The interactions of some MPc’s with the solvent molecules can lead to their decomposition as was found for example for the indium monophthalocyanine complex. InPcI after thermal process- ing in the acetylacetone–water system undergoes decomposition with the formation of magnetically frustrated indium diacetate hydroxide coordination polymer [12]. Another examples of the active role of the solvent are interactions of the hafnium monopht- halocyanine, HfPcI 2 Pht (Pht = phthalonitrile), with acetylacetone http://dx.doi.org/10.1016/j.poly.2014.07.027 0277-5387/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: j.janczak@int.pan.wroc.pl (J. Janczak). Polyhedron 81 (2014) 695–704 Contents lists available at ScienceDirect Polyhedron journal homepage: www.elsevier.com/locate/poly