Tricarbonylchromium complexes of αβγδ-tetraphenylporphinzinc

Abstract

Szcmmury Complexes of Maya-tetraphenylporphinzinc in which one and two of the phenyl rings are n-substituted with tricarbonylchromium groups have been prepared and characterized.ELECTRON distribution in metallo-porphyrins is of considerable importance in many life processes, for example in photosynthesis and cell energy transfer (cytochromes in particular). We have prepared two complexes of a series the study of which should help the understanding of electron distribution and transfer in the porphyrin system. These are complexes of aPy8-tetraphenylporphinzinc, Zn(tpp) , in which a tricarbonylchromium group is attached to one and two of the phenyl rings.The complexes were prepared by allowing Cr(CO), and Zn(tpp) to react in refluxing di-n-butyl ether in an atmosphere of pure nitrogen. Chromatography of the resulting material on Florisil yielded three bands, a red band, Zn(tpp) , a brownish-green band, (I), and a greenish-brown band, (11). Details of the spectra of these compounds are given in the Table . The n.m.r. assignments follow those of Webb is typical of tricarbonyl-n-arenechromiums. The n.m.r. spectra of both compounds consist of three main areas, @

Mass spectral studies of some π‐benzoylcyclopentadienylmanganese tricarbonyl derivatives

“…4 The mass spectra were recorded with an HitachiPerkin-Elmer RMU-6E spectrometer using a direct inlet system at an ionizing potential of 70 eV. The ion chamber temperature was kept at 90 "C. The percentage abundance quoted in this study is taken relative to the most intense peak.…”

π-Metal complexes of tetrapyrrolic systems. A novel coordination mode in “porphyrin-like” chemistry

“…The first example wherein the p-system of a peripheral porphyrin substituent was shown to participate in coordination to a metal center was described by Gogan and Siddiqui in the early 1970s. 4,5 In this seminal work, tetraphenylporphyrin (TPP) and several metallotetraphenylporphyrins were reacted with [Cr(CO) 6 ] in di-n-butyl ether at reflux under nitrogen atmosphere; this yielded monofunctionalized complexes of type 1 in good yield (Fig. 1).…”

“…Calix [4]pyrrole 16 (see Fig. 9), also called meso-octaalkylporphyrinogen, has received considerable attention in recent years for its anion binding properties.…”

“…This richness, which is thought to reflect the inherent flexibility associated with the ''pivotal'' meso-sp 3 carbon atoms, allows each pyrrole unit to behave as an independent Z 1 , Z 3 , or Z 5 binding site for a metal ion, depending on the requirements of the metallic fragment. It is perhaps no surprise, therefore, that calix [4]pyrrole represents the tetrapyrrolic ''porphyrin-like'' species whose p-coordination chemistry has been most thoroughly explored. In fact, at present, examples of p-bound complexes of this macrocycle are known with alkali and alkaline earth ions, transition metals fragments, and lanthanide and actinide cations.…”

“…In most studies involving the coordination chemistry of calix [4]pyrrole, the ligand has been used in its tetraanionic form, a species formed through deprotonation with lithium, sodium or potassium reagents. Therefore, species where pyrrolyl anions interact with alkaline cations through what can be considered as ''p-solvation'' are rather common.…”