Crystal structure of chlorido(5,10,15,20-tetraphenylporphyrinato-κ4 N)manganese(III) 2-aminopyridine disolvate

In the title compound, the chlorido(5,10,15,20-tetraphenylporphyrinato)manganese(III) complex and the hydrogen-bonded dimer of 2-aminopyridine molecules are linked together by weak N—H⋯Cl hydrogen bonds into chains along the a axis.

In the title compound, [Mn(C 44 H 28 N 4 )Cl]Á2C 5 H 6 N 2 , the Mn III centre is coordinated by four pyrrole N atoms [averaged Mn-N = 2.012 (4) Å ] of the tetraphenylporphyrin molecule and one chloride axial ligand [Mn-Cl = 2.4315 (7) Å ] in a square-pyramidal geometry. The porphyrin macrocycle exhibits a non-planar conformation with major ruffling and saddling distortions. In the crystal, two independent solvent molecules form dimers through N-HÁ Á ÁN hydrogen bonding. In these dimers, one amino N atom has a short MnÁ Á ÁN contact of 2.642 (1) Å thus completing the Mn environment in the form of a distorted octahedron, and another amino atom generates weak N-HÁ Á ÁCl hydrogen bonds, which link further all molecules into chains along the a axis.

Chemical context
In a continuation of our studies of metalloporphyrins, which are usually used as models of hemoproteins and have various applications in many fields such as catalysis (Amiri et al., 2014), photodynamic therapy (Kolarova et al., 2005), conception of sensors (Garg et al., 2013) or the design of photoluminescent species (Harry et al., 2003), we report herein the synthesis and crystal structure of the title compound, [Mn(C 44 H 28 N 4 )Cl]Á2C 5 H 6 N 2 , (I).

Structural commentary
In (I), the central Mn III atom has a square-pyramidal coordination geometry (Fig. 1). The equatorial plane is formed by ISSN 2056-9890 four nitrogen atoms of the porphyrin whereas the apical position is occupied by the chlorido ligand. The asymmetric unit of (I) consists of the [Mn III (TPP)Cl] complex (TPP is the 5,10,15,20-tetraphenylporphyrinato ligand) and two 2-aminopyridine solvent molecules. The average equatorial manganese-N(pyrrole) distance (Mn-N p ) is 2.012 (4) Å , while the Mn-Cl bond length is 2.4315 (7) Å . The manganese atom is displaced by 0.1616 (5) Å from the 24-atom porphyrin mean plane. The porphyrin core presents a major ruffling deformation, as seen in the positions of the meso carbons alternatively above and below the mean plane of the 24-atom porphyrin macrocycle, and a saddle distortion involving the displacement of the pyrrole rings alternately above and below the porphyrin macrocycle mean plane (Scheidt & Lee, 1987). This is confirmed by normal structural decomposition (NSD) calculations (Jentzen et al., 1998), with ruffling and saddle percentages of 40% and 36%, respectively.

Supramolecular features
In the crystal structure, two 2-aminopyridine solvent molecules are paired into dimers via N-HÁ Á ÁN hydrogen bonds involving the amino groups of these two molecules (Table 1). In these dimers, one amino atom has a short MnÁ Á ÁN contact of 2.642 (1) Å and another amino atom generates weak N-HÁ Á ÁCl hydrogen bonds, which further link the components into chains along the a-axis direction (Fig. 2).

Synthesis and crystallization
To a solution of [Mn III (TPP)Cl] (100 mg, 0.142 mmol) (Cheng & Scheidt, 1996)  The contents of the asymmetric unit of (I), showing the atomic numbering. Displacement ellipsoids are drawn at the 50% probability level. H atoms are omitted for clarity.

Figure 2
A portion of the crystal packing showing the N-HÁ Á ÁCl hydrogen bonds (dotted blue lines) and short MnÁ Á ÁN contacts (dashed pink lines). Table 1 Hydrogen-bond geometry (Å , ). excess of 2-aminopyridine (50 mg, 0.531 mmol). The reaction mixture was stirred at room temperature for 12 h. Crystals of the title complex were obtained by diffusion of hexanes through the chlorobenzene solution.

Refinement details
Crystal data, data collection and structure refinement details are summarized in Table 2. All H atoms were fixed geometrically and treated as riding, with C-H = 0.93, N-H = 0.86 Å and with U iso (H) = 1.2U eq (C, N).