Nuclear magnetic resonance study of the molecular and electronic structure of nickel(II) tetraphenyl-21-thiaporphyrins

Lisowski, Jerzy; Latos‐Grażyński, Lechosław; Szterenberg, Ludmiła

doi:10.1021/ic00036a039

Cited by 37 publications

(50 citation statements)

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“…The σ orbital of the oxygen atom and the porphyrin π orbitals are not orthogonal, and consequently σϪπ overlap permits the direct spin-density transfer. [57,58] We therefore suggest a similar delocalization mechanism to that proposed for [(2-O-TPP)Fe III ] 3 , although with a different location of the external coordinating center. [16] The linewidths of the β-H pyrrole resonances correlate with their specific locations within the dimeric structure.…”

Section: H Nmr Spectroscopic Studies Of [(5-o-trpp)fe III ]supporting

confidence: 61%

Monomeric and Dimeric Iron(III) Complexes of 5‐Hydroxy‐10,15,20‐triphenylporphyrin: Formation of Cyano and Pyridine Complexes of (5‐Oxo‐10,15,20‐triphenylphlorin)iron

Wojaczyński

Stępień

Latos‐Grażyński

2002

Euro J of Inorganic Chem

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The reaction of [(TrPP)FeII(py)2] (TrPP = dianion of 5,10,15‐triphenylporphyrin) with hydrogen peroxide results in oxygenation of the (porphyrin)iron and the formation of (10,15,20‐triphenyl‐5‐oxophlorin)iron [(5‐O‐TrPP)Fe(py)2]. Coupled oxidation of [(TrPP)FeIIICl] in the presence of ascorbic acid and potassium cyanide in methanol leads to oxidative hydroxylation of the porphyrin ring to form a cyclic dimer [(5‐O‐TrPP)FeIII]2. Three out of four pyrrole 1H NMR resonances of the dimeric complex present the characteristic displacement with respect to the typical position for the high‐spin (tetraphenylporphyrin)iron(III) complexes. The linewidths of the β‐H pyrrole resonances correlate with specific locations of the respective protons within the dimeric structure. Addition of HCl to [(5‐O‐TrPP)FeIII]2 results in cleavage of the dimer producing [(5‐OH‐TrPP)FeIIICl]. [(5‐O‐TrPP)FeIII]2 is also split with acetic anhydride to give (5‐acetoxy‐10,15,20‐triphenylporphyrin)iron(III). In the presence of [D5]pyridine or a large excess of cyanide ion, [(5‐O‐TrPP)FeIII]2 undergoes cleavage to form air‐sensitive [(5‐O‐TrPP)Fe(py)2] or [(5‐O‐TrPP)Fe(CN)2]2−. The pyrrole pattern observed for [(5‐O‐TrPP)Fe(py)2] is similar to that determined on the basis of an analysis carried out for four (oxophlorin)iron regioisomers obtained from hemes. For comparison, the characteristic 1H NMR features of the typical (5‐substituted‐10,15,20‐triphenylporphyrin)iron(III) complexes have been investigated for the series of high‐spin and low‐spin complexes. The spin‐density distribution in the (oxophlorin)iron skeleton is dominated by the radical‐like electronic structure. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

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Section: H Nmr Spectroscopic Studies Of [(5-o-trpp)fe III ]supporting

confidence: 61%

Monomeric and Dimeric Iron(III) Complexes of 5‐Hydroxy‐10,15,20‐triphenylporphyrin: Formation of Cyano and Pyridine Complexes of (5‐Oxo‐10,15,20‐triphenylphlorin)iron

Wojaczyński

Stępień

Latos‐Grażyński

2002

Euro J of Inorganic Chem

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“…All three metal complexes have chloride as axial ligands and were paramagnetic in nature. Later, Latos-Grażyński and co-workers − carried out chemical and electrochemical reduction of Ni(II)2a to prepare its one-electron reduced Ni(I) complex of 21-thiaporphyrin Ni(I)2a and characterized the complex Ni(I)2a thoroughly (Scheme ). The same group also investigated the reactivity of the axial chloride (Cl) ligand by reacting Ni(II)2a with Grignard reagent (PhMgBr) to afford Ni(II)2a(Ph) , in which the axial chloride ligand was replaced by phenyl group (Scheme ).…”

Section: Metal Complexes Of Heteroporphyrinsmentioning

confidence: 99%

Heteroatom-Containing Porphyrin Analogues

Shetti²,

et al. 2016

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The heteroatom-containing porphyrin analogues or core-modified porphyrins that resulted from the replacement of one or two pyrrole rings with other five-membered heterocycles such as furan, thiophene, selenophene, tellurophene, indene, phosphole, and silole are highly promising macrocycles and exhibit quite different physicochemical properties compared to regular azaporphyrins. The properties of heteroporphyrins depend on the nature and number of different heterocycle(s) present in place of pyrrole ring(s). The heteroporphyrins provide unique and unprecedented coordination environments for metals. Unlike regular porphyrins, the monoheteroporphyrins are known to stabilize metals in unusual oxidation states such as Cu and Ni in +1 oxidation states. The diheteroporphyrins, which are neutral macrocycles without ionizable protons, also showed interesting coordination chemistry. Thus, significant progress has been made in last few decades on core-modified porphyrins in terms of their synthesis, their use in building multiporphyrin arrays for light-harvesting applications, their use as ligands to form interesting metal complexes, and also their use for several other studies. The synthetic methods available in the literature allow one to prepare mono- and diheteroporphyrins and their functionalized derivatives, which were used extensively to prepare several covalent and noncovalent heteroporphyrin-based multiporphyrin arrays. The methods are also developed to synthesize different hetero analogues of porphyrin derivatives such as heterocorroles, heterochlorins, heterocarbaporphyrinoids, heteroatom-substituted confused porphyrins, and so on. This Review summarizes the key developments that have occurred in heteroporphyrin chemistry over the last four decades.

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“…13,15 The characteristic ESR and 1 H NMR parameters of Ni(I) coordinated to thiaporphyrin have been established. [19][20][21] Nickel(II) and nickel(I) porphyrins and related compounds have been widely studied because of the growing interest in nickel(II) hydrocorphinoid derivatives, i.e. factor F 430 which was identified as the active site of the coenzyme M methyl reductase (from Methanobacterium thermoautotrophicum).…”

Section: Introductionmentioning

confidence: 99%

5,20-Diphenyl-10,15-bis(p-tolyl)-21-selenaporphyrin and Its Nickel(II) Complexes¹

et al. 1996

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The synthesis of a new monoheteroporphyrin, 5,20-diphenyl-10,15-bis(p-tolyl)-21-selenaporphyrin (SeDPDTPH), is reported. The 21-selenaporphyrin has been characterized by 1H NMR, 13C NMR, mass spectrometry, and UV−visible spectra and an X-ray structural analysis. The free base selenaporphyrin SeDPDTPH crystallizes in the monoclinic space group P21/n with a =19.848(3) Å, b = 8.8410(14) Å, c = 20.503(4) Å, β = 103.375(12)° at 125 K with Z = 4. Refinement of all 4577 unique reflections and 453 parameters yielded R 1 = 0.096 (based on F 2). The presence of selenium atom elongates the macrocycle along the N(1)−N(3) axis when compared to a regular porphyrin. The π delocalization pattern is altered in the selenophene moiety in relation to the free selenophene. SeDPDTPH undergoes a two-step proton addition in solution. Mono- and dication formation results in distortion of the planar 21-selenaporphyrin structure. The monocation structure is solvent dependent as shown by the 1H NMR titration experiments. Insertion of Ni(II) into 21-selenaporphyrin yields NiII(SeDPDTP)Cl (S = 1, μeff = 3.3 μB). The electronic spectrum of this complex is porphyrin-like with a strong Soret band at 433 nm. The 1H NMR spectra of the high-spin nickel(II) complexes of 21-selenaporphyrin have been recorded and assigned by means of the selective deuteration, line width considerations, and a 2D COSY experiment. The characteristic pattern of pyrrole (downfield) and selenophene (upfield) resonances has been established. Direct σ-π spin density transfer has been proposed to explain the upfield shift of the selenophene protons. Imidazole replaces the chloride ligand to form five- and six-coordinate complexes. The spectroscopic and chemical properties of NiII(SeDPDTP)Cl resemble those of nickel(II) complexes with 21-thiaporphyrin. To account for these similarities, we suggest that the selenophene moiety is bent out of the porphyrin plane in NiII(SeDPDTP)Cl. Such a geometry allows metal ion to interact with selenium of selenophene in a side-on fashion.

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Nuclear magnetic resonance study of the molecular and electronic structure of nickel(II) tetraphenyl-21-thiaporphyrins

Cited by 37 publications

References 4 publications

Monomeric and Dimeric Iron(III) Complexes of 5‐Hydroxy‐10,15,20‐triphenylporphyrin: Formation of Cyano and Pyridine Complexes of (5‐Oxo‐10,15,20‐triphenylphlorin)iron

Monomeric and Dimeric Iron(III) Complexes of 5‐Hydroxy‐10,15,20‐triphenylporphyrin: Formation of Cyano and Pyridine Complexes of (5‐Oxo‐10,15,20‐triphenylphlorin)iron

Heteroatom-Containing Porphyrin Analogues

5,20-Diphenyl-10,15-bis(p-tolyl)-21-selenaporphyrin and Its Nickel(II) Complexes¹

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Nuclear magnetic resonance study of the molecular and electronic structure of nickel(II) tetraphenyl-21-thiaporphyrins

Cited by 37 publications

References 4 publications

Monomeric and Dimeric Iron(III) Complexes of 5‐Hydroxy‐10,15,20‐triphenylporphyrin: Formation of Cyano and Pyridine Complexes of (5‐Oxo‐10,15,20‐triphenylphlorin)iron

Monomeric and Dimeric Iron(III) Complexes of 5‐Hydroxy‐10,15,20‐triphenylporphyrin: Formation of Cyano and Pyridine Complexes of (5‐Oxo‐10,15,20‐triphenylphlorin)iron

Heteroatom-Containing Porphyrin Analogues

5,20-Diphenyl-10,15-bis(p-tolyl)-21-selenaporphyrin and Its Nickel(II) Complexes1

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5,20-Diphenyl-10,15-bis(p-tolyl)-21-selenaporphyrin and Its Nickel(II) Complexes¹