(2,3,5,10,12,13,15,20-Octa­phenyl­porphinato)copper(II) 1,1,2,2-tetra­chloro­ethane solvate

The title complex, [Cu(C68H44N4)]·C2H2Cl4, exhibits nearly square-planar geometry around the CuII centre and the macrocyclic ring is almost planar. The porphyrin mol­ecule has an approximate non-crystallographic inversion centre (Ci), and a non-crystallographic twofold rotation axis (C 2) within the CuII–porphyrin ring plane. Further, it has non-crystallographic twofold rotation axis and mirror plane (Cs) symmetry perpendicular to the mol­ecular plane. The mol­ecular packing of the complexes and the solvent molecules shows weak inter­molecular C—H⋯π, C—H⋯Cl and C—H⋯N inter­actions, forming a clathrate-like structure

Influence of steric hindrance on the solvent-dependent absorption spectral behavior of highly brominated free base porphyrin and its <font>Zn</font>(II) complex

Electronic absorption spectra of highly brominated free base porphyrin, 2,3,7,8,12,13,17,18-octabromo-tetrakis(2′,6′-dibromo-3′,5′-dimethoxyphenyl)porphyrin, H 2 T (3′,5′-DMP) PBr 16 and its Zn (II) complex were examined in various solvents. These derivatives exhibit red-shifted absorption spectral features in polar solvents relative to that observed in less polar or nonpolar solvents. The extent of red shifts observed in highly brominated porphyrins is less than those reported for the corresponding 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin, H 2 TPPBr 8 and its Zn (II) complex. The crystal structure of the H 2T(3′,5′-DMP) PBr 16 showed saddle-shaped geometry with steric hindrance of the bromo groups on the opposite phenyl rings which provide limited open access to the core. The decreased red shift of the absorption spectral bands of MT (3′,5′-DMP) PBr 16 ( M = 2 H , Zn (II)) derivatives when compared to unhindered MTPPBr 8 is possibly due to the steric hindrance offered by the ortho-bromo groups rather than the electronic effects of the porphyrin π-system. </jats:p

Unusual solvent dependent electronic absorption spectral properties of nickel(II) and copper(II) perhaloporphyrins

Electronic absorption spectra of divalent metal ( Ni (II) and Cu (II)) complexes of 2,3,7,8,12,13,17,18-octa(bromo/chloro)-5,10,15,20-tetraphenylporphyrins (MOXTPP; X = Br , Cl ) were examined in various solvents. M (II) perhaloporphyrins exhibited dramatic shifts in their optical absorption spectral features relative to the corresponding metallotetraphenylporphyrins, MTPPs. Copper(II) perhaloporphyrins show significant red-shifts of the absorption bands in coordinating solvents relative to that observed for nickel(II) perhaloporphyrins. The large red-shift of the electronic absorption bands and the gain in intensity of the longest wavelength band (Q(0,0)), of Cu (II) perhaloporphyrins in certain coordinating solvents is comparable to that found in meso-tetraphenylporphinatozinc(II), ZnTPP. The solvent dependent spectral features of M (II) perhaloporphyrins are attributed to a coordinative interaction of the solvent with the core metal ion induced by the electron deficient porphyrin macrocycle. </jats:p