Iris M. Oppel

Isomorphous free-base, Ni(II)- and Cu(II)-5,10,15,20-tetra(4-hydroxyphenyl)porphyrin nitrobenzene hexasolvates with tetragonal 3D hydrogen-bonded network structures

The crystal structures of 5,10,15,20-tetra(4-hydroxyphenyl)-21,23H-porphyrin nitrobenzene hexasolvate (1), 5,10,15,20-tetra(4-hydroxyphenyl)porphyrinatonickel(II) nitrobenzene hexasolvate (2) and 5,10,15,20-tetra(4-hydroxyphenyl)porphyrinatocopper(II) nitrobenzene hexasolvate (3) are described. Compounds 1–3 crystallise isomorphously in the non-centrosymmetric tetragonal space group P4cc with Z = 8. There are three crystallographically distinct porphyrin molecules, two of which contain fourfold axes perpendicular to the porphyrin plane. The remaining one contains a twofold axis perpendicular to the porphyrin ring system. The porphyrin building blocks are joined into a three-dimensional network through self-complementary O–H⋯O hydrogen bonding interactions between 4-hydroxyphenyl groups of adjacent molecules. The space occupied by the nitrobenzene solvent molecules is remarkably large at ca. 61.5% of the unit cell volume in 1–3.

(Hexafluorosilicato-ƙ-2F,F')bis(1,10-phenanthroline-ƙ2N,N')zinc(II) methanol monosolvate

The title compound, [Zn(SiF6)(C12H8N2)2]·CH3OH, contains a neutral heteroleptic tris-chelate Zn(II) complex, viz. [Zn(SiF6)(phen)2] (phen is 1,10-phenanthroline), exhibiting approximate molecular C2 point-group symmetry. The Zn(II) cation adopts a severely distorted octahedral coordination. As far as can be ascertained, the title complex represents the first structurally characterized example of a Zn(II) complex bearing a bidentate-bound hexafluorosilicate ligand. A density functional theory study of the isolated [Zn(SiF6)(phen)2] complex was undertaken to reveal the influence of crystal packing on the molecular structure of the complex. In the crystal structure, the methanol solvent molecule forms a hydrogen bond to one F atom of the hexafluorosilicate ligand. The hydrogen-bonded assemblies so formed are tightly packed in the crystal, as indicated by a high packing coefficient (74.1%).

Redetermination of cyclo-tetra­kis­(μ-5,10,15,20-tetra-4-pyridyl­porphyrinato)tetra­zinc(II) dimethyl­formamide octa­solvate trihydrate at 100 K

The structure of the title compound, [Zn4(C40H24N8)4]·8C3H7NO·3H2O, has been redetermined at 100 K. The redetermination is of significantly higher precision and gives further insight into the disorder of pyridyl groups and solvent molecules. The molecules of (5,10,15,20-tetra-4-pyridylporphyrinato)zinc(II) (ZnTPyP) form homomolecular cyclic tetramers by coordination of a peripheral pyridyl group to the central Zn atom of an adjacent symmetry-related molecule. The tetramer so formed exhibits molecular S 4 symmetry and is located about a crystallographic fourfold rotoinversion axis. Severely disordered dimethylformamide and water molecules are present in the crystal, the contributions of which were omitted from refinement. Intermolecular C—H⋯N hydrogen bonding is observed.

A synchrotron study of [5,10,15,20-tetra­kis­(3-cyano­phen­yl)porphyrinato-κ4N5,N10,N15,N20]copper(II) nitro­benzene tris­olvate at 80 K

Porphyrin assemblies display interesting photophysical properties and a relatively high thermal stability. Moreover, meso-functionalized porphyrins with virtually fourfold symmetry can be relatively readily synthesized from pyrrole and the appropriate aldehyde. A number of metallo derivatives of 5,10,15,20-tetrakis(4-cyanophenyl)porphyrin, where the N atom of the linear cyano group can act both as a donor for coordination bonds or as an acceptor for hydrogen bonds, have been structurally characterized by single-crystal X-ray analysis. The supramolecular and structural chemistry of the corresponding 2- and 3-cyanophenyl isomers of the parent porphyrin, however, has remained largely unexplored. The crystal structure of [5,10,15,20-tetrakis(3-cyanophenyl)porphyrinato]copper(II) (CuTCNPP) nitrobenzene trisolvate, [Cu(C48H24N8)]·3C6H5NO2, has been determined at 80 K by synchrotron single-crystal X-ray diffraction. CuTCNPP exhibits a C2h-symmetric ααββ conformation, despite an unsymmetrical crystal environment, and is situated on a crystallographic centre of symmetry. The CuII ion adopts a genuine square-planar coordination by the four pyrrole N atoms. The 24-membered porphyrin ring system shows no marked deviation from planarity. In the crystal, the CuTCNPP molecules and two nitrobenzene molecules are face-to-face stacked in an alternating fashion, resulting in corrugated layers. The remaining nitrobenzene guest molecule per CuTCNPP resides in the region between four neighbouring columnar stacks of CuTCNPP and sandwiched nitrobenzene molecules, and is disordered over four positions about a centre of symmetry.