Tin porphyrins complexes

One example of a tin porphycene has been reported, but as yet no organometallic derivatives have been reported." A small number of tin corrole complexes are known including one organotin example, Sn(OEC)Ph, prepared from the reaction of Sn(OEC)Cl with PhMgBr. A crystal structure of Sn(OEC)Ph shows it to have both shorter Sn—N and Sn—C bonds than Sn(TPP)Ph2, with the tin atom displaced 0.722 A above the N4 plane of the domed macrocycle (Fig. 6). The complex undergoes reversible one-electron electrochemical oxidation and reduction at the corrole ring, and also two further ring oxidations which have no counterpart in tin porphyrin complexes. " " ... 

Arnold DP, Blok J.The coordination chemistry of tin porphyrin complexes. Coord Chem Rev 2004 248 299-319. 

Reports on simple transition metal compounds of tin include the preparation of [Cp Ni(CD)(SnPh3)] , iron-tin porphyrin complexes , mixed tin-silicon compounds [Fe(CD)3... 

Porphyrin, octaethyl-, tin dihydroxide complex cyclic voltammetry, 4, 399 <73JA5140)... 

The range of organo-silicon, germanium, tin, and lead porphyrin complexes reported to date are given in Table Some mono- and dialkyltin... 

The lack of adequate experimental data on chelates of germanium, boron, titanium, and vanadium prevents a similar comparison for these elements however, their high ionic potentials do indicate that they should form stable chelates. Vanadium does occur naturally in the very stable vanadium porphyrin complex. For similar reasons, molybdenum and tin are not discussed further. 

The last category was concerned with miscellaneous subjects, while citing some chirogenic porphyrin-based systems. Representative reviews include chiral lanthanide complexes by Aspinall [41], coordination chemistry of tin porphyrins by Arnold and Blok [42], photoprocesses of copper complexes that bind to DNA by McMillin and McNett [43], nonplanar porphyrins and their significance in proteins by Shelnutt et al. [44], cytochrome P450 biomimetic systems by Feiters, Rowan, and Nolte [45] and phthalocyanines by Kobayashi [46,47]. 

Bis-amido tin porphyrins trans (TTP)Sn(N(R)Ph)2 (R = H, Ph) and cis (TTP)Sn(l,2-(NH)2C6H4) have been prepared and shown to be more stable than the analogous Sn—C bonded alkyl or aryl complexes. The increased stability of these nitrogen bound ligands is probably a function of their increased basicity. ... 

Snn. If Sn11 salts are reacted with porphyrins one usually obtains SnIV porphyrins, but in rigorously dried and degassed pyridine another complex is obtained with a Soret band close to 460 nm [Whitten (203)]. This could not be demetalated, neither could the metal be exchanged with copper salts. The latter treatment results, however, in formation of SnIV porphyrins. Reduction of SnIV porphyrins with sodium boro-hydride leads to tin porphyrins which can be demetalated by hydrochloric acid, but no 460 nm band is found in the reaction mixture [Fuhrhop (75)]. Thus, the properties of Sn11 porphyrins remain unconfirmed. 

Episulftdes. In a conversion ol tin(IV)-porphyrin complex, thiourea hi 1,3-Dioxolane cleavage.- Hydi thiourea in aqueous ethanol at refl< substrates such as l,2 5,6-di-0-i acetonide is cleaved. 

However, the luminescence measurements show quenching of fluorescence in the trimer, which is attributed to a photo-induced electron transfer from the axial ruthenium(II) porphyrin to the excited state of the basal tin porphyrin. Not only ruthenium(II) porphyrins, but also rhodium(III) porphyrins can easily be incorporated into the arrays with the same strategy [33]. Again, the isonicotinic acid is first reacted with the bis-hydroxy tin porphyrin to give the bis-isonicotinic acid complex. Addition of two equivalents of rhodium(III) porphyrin readily yields the trimeric array of the composition Rh-Sn-Rh. The X-ray structure of this complex, which is shown in Fig. 34c, shows that the ligands on the tin center (carboxylates) are in an off-direction which is close to orthogonal to the porphyrin plane, and the three porphyrins adopt a near coplanar arrangement. The tin porphyrin is tilted by about 8.6° with respect to the rhodium(III) porphyrins. 

Self-assembled monolayers of an Os3(CO)s CN(CH2)3Si(OEt)3)(ft3-ri rf if-C6o) cluster on indium-tin oxide or gold surfaces have been shown to be electrochemically stable, being reducible to tetra-anionic species in their cyclic voltammograms. Further derivatization through tethering a zinc porphyrin complex to the cluster generated a high-performance photovoltaic cell with potential applications in artificial photosynthesis. ... 

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