Self-organization of phthalocyanines (Pc) as a result of stacking interaction between aromatic rings provides, in

Cobalt(II), nickel(II), and copper(II) complexes containing 5,12-di(4-bromophenyl)-7, 14-dimethyl-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-dione (H 2 L 1 ) and 5,12-diphenyl-7,14-dimethyl-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-dione (H 2 L 2 ) have been synthesized. All complexes were characterized by elemental analysis, MALDI TOF-MS spectrometry, and electronic absorption spectroscopy. The crystal structures of two compounds, [Cu 2 (H 2 L 1 )Cl 4 ] n and [NiL 2 ], were determined by X-ray powder diffraction. In the polymeric [Cu 2 (H 2 L 1 )Cl 4 ] n , the Cu 2 Cl 4 units and H 2 L 1 molecules are situated on inversion centers. Each Cu(II) has a distorted trigonal-bipyramidal coordination environment formed by N and O from H 2 L 1 [Cu-N 2.340(14) Å, Cu-O 1.952(11) Å], two bridging chlorides [Cu-Cl 2.332(5), 2.279(5) Å] and one terminal chloride [Cu-Cl 2.320(6) Å]. In the [NiL 2 ] complex, the Ni(II) situated on inversion center has a distorted square-planar coordination environment formed by four nitrogens from L 2 [Ni-N 1.860(11), 1.900(11) Å].

The features of porphyrins defining their functionality are related to their conformational flexibility. The degree of nonplanarity of metalloporphyrins depends directly on the number of substituents, their size and their location. The introduction of substituents in the meso positions of β-substituted porphyrins increases the steric interaction and leads to distortions of the porphyrin core. Increasing the distortion of the porphyrin core would augment the bathochromic (red) shift of the electronic absorption spectra. A new nonsymmetrical 2,3,7,8,12,13,17,18-octaethyl-5-[(methylimino)methyl]porphyrin complex of palladium(II), [Pd(CHN)], was synthesized and characterized by NMR, mass spectrometry and X-ray analysis. The features of the electronic absorption spectrum of the synthesized complex are explained by the planarity of the porphyrin core and the π-system of the imino group orthogonal to it.

Porphyrin complexes of ruthenium are widely used as models for the heme protein system, for modelling naturally occurring iron-porphyrin systems and as catalysts in epoxidation reactions. The structural diversity of ruthenium complexes offers an opportunity to use them in the design of multifunctional supramolecular assemblies. Coproporphyrins and metallocoproporphyrins are used as sensors in bioassay and the potential use of derivatives as multiparametric sensors for oxygen and H is one of the main factors driving a growing interest in the synthesis of new porphyrin derivatives. In the coproporphyrin I Ru complex catena-poly[[carbonylruthenium(II)]-μ-2,7,12,17-tetrakis[2-(ethoxycarbonyl)ethyl]-3,8,13,18-tetramethylporphyrinato-κN,N',N'',N''':O], [Ru(CHNO)(CO)], the Ru centre is coordinated by four N atoms in the basal plane, and by axial C (carbonyl ligand) and O (ethoxycarbonylethyl arm from a neighbouring complex) atoms. The complex adopts a distorted octahedral geometry. Self-assembly of the molecules during crystallization from a methylene chloride-ethanol (1:10 v/v) solution at room temperature gives one-dimensional polymeric chains.

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