1,8-Diazabicyclo[5.4.0]undec-7-en-8-ium bromido(phthalocyaninato)zincate

The title compound, (C9H17N2)[ZnBr(C32H16N8)], contains a bromido(phthalocyaninato)zincate anion and a protonated 1,8-diazabicyclo[5.4.0]undece-7-ene cation, [DBUH]+. The central ZnII atom has a distorted square-pyramidal geometry, with four isoindole N atoms of the macrocycle in equatorial positions and a bromide ion in the axial position. The latter has a relatively high displacement parameter, but no evidence for disorder was obtained. The central ZnII atom is displaced by 0.488 (3) Å from the mean plane defined by the four isoindole N atoms. The [DBUH]+ cation is involved in an almost linear N—H⋯Br hydrogen bond. In the crystal, π–π interactions lead to a relatively short distance of 3.366 (3) Å between the phthalocyaninate rings.

The title compound, (C 9 H 17 N 2 )[ZnBr (C 32 H 16 N 8 )], contains a bromido(phthalocyaninato)zincate anion and a protonated 1, 8-diazabicyclo[5.4.0]undece-7-ene cation, [DBUH] + . The central Zn II atom has a distorted square-pyramidal geometry, with four isoindole N atoms of the macrocycle in equatorial positions and a bromide ion in the axial position. The latter has a relatively high displacement parameter, but no evidence for disorder was obtained. The central Zn II atom is displaced by 0.488 (3) Å from the mean plane defined by the four isoindole N atoms. The [DBUH] + cation is involved in an almost linear N-HÁ Á ÁBr hydrogen bond. In the crystal,interactions lead to a relatively short distance of 3.366 (3) Å between the phthalocyaninate rings.
This work was supported by the Ministry of Science and Higher Education (grant No. N N204 397540).

Comment
Phthalocyanines and metallophthalocyanines (Pcs and MPcs) arouses interest because of exhibition of many important features which gives potential application in many fields from industry to medicine (Leznoff & Lever, 1996;Gregory, 2000). 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 the the metal centre of MPcs. Both ways of modification of MPc's lead to improvment of their solubility, due to decreasing of the π···π interactions between the Pc macrocycles as well as lowering their aggregation in solution. ZnPc and its derivatives, due to strong absorption in the red region of visible radiation and high triplet quantum yield and long lifetimes, are intensively studied as potential agents in photodynamic therapy (Tedesco et al., 2003;Ormond & Freeman, 2013).
Complex 1 crystallizes as ionic compound in the centrosymmetric space group of monoclinic system. The blue-violet crystals of 1 are built up from bromido(phthalocyaninato)zinc(II) anion (ZnPcBr -) and 1,8-diazabicyclo[5.4.0]undec-7en-8-ium cation (DBUH + ) (Fig. 1). Both oppositely charged units interact via N-H10···Br hydrogen-bond, in which DBUH + plays role of a donor (Table 1). Due to presence of DBU that accepts H + , phthalocyaninato macrocyle maintains -2 oxidation state, therefore the complex 1 is diamagnetic as show the magnetic susceptibility measurements. This is in contrast to the chloro(phthalocyaninato)zinc(II) in which ZnPc is oxidised and has +1 charge, and the metal centre is coordinated by phthalocyaninato anion with π-radical character, Pc -. (Mossoyan-Deneux et al., 1985). As an effect of monaxial Zn-Br bond formation, Zn(II) atom exhibits displacement from a plane defined by four isoindole nitrogen atoms of Pc(2-) (N 4 plane) by 0.488 (3) Å. This is a value situated in the typical range in comparison with other 4+1 complexes of ZnPc reported in the literature (Table S1). Additionally, pyramidal coordination environment of Zn(II) centre is slightly distorted, angle between the normal to the N 4 plane and the Zn-Br bond is equal 1.65 (5) ° that is inclined towards the hydrogen-bond. In reported structure Pc(2-) macrocycle has nearly flat conformation though deformation from flat to saucer-like shape is very common among 4+1 MPc complexes arranged in the back-to-back fashion in solids. Almost all nitrogen and carbon atoms of Pc(2-) exhibit displacement from the mean plane of these atoms smaller than 0.1 Å (only three peripheral carbon atoms slightly exceed this value). Complex of ZnPc with chloride (Mossoyan-Deneux et al., 1985) also exhibits nearly flat conformation of Pc(2-) macrocycle, thus deformation of the molecule into saucer-like shape is probably caused by interaction with bulky ligands like amines or pyridine derivatives (Table S1). Mutual arrangement of the complex molecules exhibits typical back-to-back fashion, with the distance 3.366 (3) Å, as a consequence of π···π interaction between Pc(2-) macrocycles. Back-to-back oriented molecules exhibits relatively small shift in plane of Pc(2-) macrorings (Fig. 2).
Thanks to DBU molecule that plays role of acceptor H + , ligation of ZnPc by Brwith the formation of the ionic complex HOMO-LUMO level is not disturbed. The Q band assigned to HOMO-LUMO transition is observed at almost the same wavelength of ~673 nm in both complexes (ZnPcBr -)(DBUH + ) and ZnPc (Nyokong et al., 1987). However, the ionic compound 1 is significantly better soluble than ZnPc pigment and therefore this feature of 1 widnes its potential utility.
The temperature dependence of the magnetic susceptibility was performed on Quantum Design SQUID magnetometer (San Diego, CA). The data were recorded at a magnetic field of 0.5 T between 1.8 and 300 K on the sample of 50 mg.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. During refinement of the crystal structure we have seen the relatively high thermal parameters of Br coordinated to ZnPc. Therefore, the composition of the crystal has been checked with energy dispersive spectroscopy (EDS) as well as with a Perkin-Elmer 2400 elemental analyser. Elemental analysis evidently points to 1:1 proportion of Zn:Br. Therefore the refinement of the crystal structure was performed with the occupation factor of 1 for Br. Hydrogen atoms were placed in calculated positions and refined using a riding model with C-H = 0.97 Å and U iso (H) = 1.5U eq (C) for aliphatic and C-H = 0.93 Å and U iso (H) = 1.2U eq (C) for aromatic moieties. H atom involved in N-H···Br bond was localized in difference maps and refined with N -H distance restrain of 0.87 (2) Å.   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq