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, @
Nitric oxide forms 1:1 low spin complexes with CruTPP, CrIMTPP(X), MnMTPP, and MnmTPP(X) species.MnTPP(X)(NO) (X-= Cl-, CH3CO2-, CN-) and CrTPP(NO) complexes have the S = 'fa ground state and EPR spectra diagnostic for the odd electron occupying a molecular orbital of predominantly metal dxy character. MnTPP(X)(NO) complexes and the isoelectronic CrTPP(NO) species are assigned the (dxzj,z)4 (dx>)1 ground configuration. Narrow lines in the isotropic EPR spectrum of CrTPP(NO) permit resolution of nitrogen-14 hyperfine from both nitric oxide (6.5 G) and the porphyrin pyrrole nitrogens (3.15 G). The metal nuclear hyperfine coupling constants in these complexes (A 55Mn) = 88.3 G and (A 53Cr> = 21.2 G are indicative of the odd electron being relatively localized on the metal. All of these nitric oxide complexes are formulated as M-NO+ species, although dir -» t* bonding substantially reduces this charge separation. Within isoelectronic sets such as (d5) MnTPP(Cl)(NO) (vno = 1830 cm-1), CrTPP(NO) (vno = 1700 cm-1), or (d6) FeTPP(CI)(NO) (mo = 1880 cm-1), MnTPP(NO) (%o = 1760 cm-1), the nitric oxide stretching frequencies are substantially smaller for the complex where the metal has the lower formal oxidation state. Electronic spectra for the chromium porphyrin species are typical for metalloporphyrins, while spectra for MnTPP(X) and MnTPP(X)(NO) complexes are highly irregular. VOTPP fails to form a nitric oxide complex even in the low temperature glass media.The coordination chemistry of diatomic molecules with metalloporphyrins is in a period of rapid development. A wide array of diatomic molecule complexes of metalloporphyrins has recently been reported.1-11 The focus of atten-
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.
α,β,γ,δ‐Tetraphenylporphinzink (I) und Chromhexacarbonyl (II) reagieren in siedendem Di‐n‐butyläther zum Tricarbonylchromkomplex (III) und zu einem Tricarbonylchromkomplex, bei dem die Tricarbonylchromgruppe an zwei Phenylreste gebunden ist.
279ChemInform Abstract The reaction of transition metal Schiff base complexes derived from salicylaldehyde and ethylenediamine, methylamine and phenylamine with Cr(CO)6 in dibutyl ether produces mainly derivatives containing a Cr(CO)3 group π-bonded to a benzene ring. In addition to complexes with a Zn chelate a σ-coordinated complex (IX) is formed. The Ni Schiff base chelates with R: -Me and -Ph react with Cr(CO)6 to give the corresponding Cr(II) chelates and a Ni mirror. The stereochemistry around the transition metal is determined by electronic spectra and magnetic susceptibility measurements. With the exception of (II) and (Ib), which are square-planar, all the four-coordinate complexes have tetrahedral and all the hexa-coordinate complexes octahedral geometry.
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