ABSTRACT
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 ß-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(C38H47N5)], 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.
ABSTRACT
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 RuII complex catena-poly[[carbonylruthenium(II)]-µ-2,7,12,17-tetrakis[2-(ethoxycarbonyl)ethyl]-3,8,13,18-tetramethylporphyrinato-κ5N,N',N'',N''':O], [Ru(C44H52N4O8)(CO)]n, the RuII 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.
ABSTRACT
The asymmetric unit of the title compound, [Cd(C(30)H(31)N(3)O(6))(2)](PF(6))(2)·3H(2)O, contains one half-cation with the Cd(II) center situated on a twofold rotational axis, one hexa-fluoridophosphate anion and two uncoordinated water mol-ecules, one of which is also situated on a twofold rotational axis. The cations are associated into columns along the a axis through π-π inter-actions between the pyridine and benzene rings, with a centroid-centroid distance of 3.72â (5)â Å. Inter-molecular O-Hâ¯O, C-Hâ¯O and C-Hâ¯F hydrogen bonds consolidate the crystal packing.
