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, @
The preparative value of the I-(phenylsulfonyl) N-blocking and directing group for the synthesis of 3-acylpyrroles has been further evaluated. Acetylation and benzoylation are strongly regiospecific and give good yields. However, the regiospecificity is not general and other substitution reactions give mixtures of 2-and 3-substitution or even mostly 2-substitution. Friedel and Crafts rert-butylation gives 3-rerr-butyl-I-(phenylsulfonyl)pyrrole and provides a useful route to rert-butylpyrrole, but ethylation and isopropylation give mixtures. Acylations of 2-and 3-alkyl-I-(phenylsulfonyl)pyrroles show little evidence of useful regiospeeifieity.
Tricarbonylchromium n-complexes of aflyh-tetraphenylporphin and its Cr(II), Mn(III), Ni(II), Cu(II), and Zn(I1) chelates have been prepared. The complexes vary in stability with the Zn compound being the most stable. The complexes have been studied by their visible and i.r. spectra and their n.m.r. spectra where applicable. A study of the CO stretching vibrations in the i.r. shows no appreciable interaction between the two metals and arguments are made to show that this lack of interaction is due to absence of n interactions between the porphin and phenyl ring systems.Les complexes n tricarbonylchrome des tttraphtnylporphines aflyh et de ses chtlates avec le Cr(II), Mn(III), Ni(II), Cu(II), et Zn(I1) ont t t t prtparts. Ces complexes, de stabilitt variable (ceux de Zn etant les plus stables), ont t t t ttudits par spectroscopie visible, i.r. et r.m.n. quand ce dernier etait applicable. L'ttude de la vibration de valence du CO a 1'i.r. ne montre aucune interaction notable entre les deux mttaux et les arguments avances pour expliquer ce fait s'appuient sur l'absence des interactions n entre la porphine et les systtmes aromatiques.
A tricarbonylmanganesetricarbonylchromiumThe mixture was again chromatographed on silica gel and, apart from unreacted starting materials, three compounds were isolated and each was recrystallized from petroleum --(60-80').These were (I) 2-benzyl-n-pyrrolylmanganese WE report the preparation and characterization of tricarbonyl, (11) 2-(n-benzylchromium tricarbonyl) pyrrole, 2-(n-benzylchromium tricarbony1)-n-pyrrolylmanganese tri-and a third compound (111) which was bright yellow in carbonyl which we believe to be the first reported compound colour and melted a t 103-104".This compound proved complex of 2-benzylpyrrole and the separate tricarbonylmetal complexes have been prepared and characterized.
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