Ruthenium Complexes of Thiaporphyrin and Dithiaporphyrin

Abstract

Successful synthesis and characterization of the six-coordinated complex [Ru(STTP)(CO)Cl] (1; STTP = 5,10,15,20-tetratolyl-21-thiaporphyrinato) allowed the development of the coordination chemistry of ruthenium-thiaporphyrin through dechlorination and metathesis reactions. Accordingly, [Ru(II)(STTP)(CO)X] (X = NO(3)(-) (2), NO(2)(-) (3), and N(3)(-) (4)) was synthesized and analyzed by single-crystal X-ray structural determination and NMR, UV-vis, and FT-IR spectroscopic methods. An independent reaction of STPPH and [Ru(COD)Cl(2)] led to [Ru(III)(STTP)Cl(2)] (5), which possessed a higher-valent Ru(III) center and exhibited good stability in the solution state. This stability allowed reversible redox processes in a cyclic voltammetric study. Reactions of [Ru(S(2)TTP)Cl(2)] (S(2)TTP = 5,10,15,20-tetratolyl-21,23-dithiaporphyrinato) with AgNO(3) and NaSePh, also via the metathesis strategy, resulted in novel dithiaporphyrin complexes [Ru(II)(S(2)TTP)(NO(3))(2)] (6) and [Ru(0)(S(2)TTP)(PhSeCH(2)SePh)(2)] (7), respectively. The structures of 6 and 7 were corroborated by X-ray crystallographic analyses. Complex 7 is an unprecedented ruthenium(0)-dithiaporphyrin with two bis(phenylseleno)methanes as axial ligands. A comparison of the analyses of the crude products from reactions of NaSePh and CH(2)Cl(2) with or without [Ru(S(2)TTP)Cl(2)], further supported by UV-vis spectral changes under stoichiometric reactions between [Ru(S(2)TTP)Cl(2)] and NaSePh, suggested a reaction sequence in the order of (1) formation of a putative [Ru(II)(S(2)TTP)(SePh)(2)] intermediate, followed by (2) the concerted formation of PhSe-CH(2)Cl and simultaneously a reduction of Ru(II) to Ru(0) and finally (3) nucleophilic substitution of PhSeCH(2)Cl by excess PhSe(-), resulting in PhSeCH(2)SePh, which readily coordinated to the Ru(0) and completed the formation of bis(phenylseleno)methane complex 7.

Rhenium(i) tricarbonyl complex of 5,20-bis(p-tolyl)-10,15-bis(p-methoxyphenyl)-21-selenaporphyrin: first X-ray structural characterization of metal complex of 21-selenaporphyrin

“…However, 21-thiaporphyrin has been shown to form four, five and six coordinate metal complexes. [5][6][7][8][9] In all metallothiaporphyrin complexes, the thiophene ring is sharply bent out of the mean plane and binds to the metal in a η 1 (S)-fashion. Interestingly, the coordination chemistry of 21-selenoporphyrin has remained elusive although one expects that 21-selenoporphyrin also prefer to form metal complexes like 21-thiaporphyrin.…”

“…However, among 21-heteroporphyrins, the metal coordination chemistry of 21-thia and 21oxaporphyrins is relatively well developed. Grażyński et al and others have shown that 21-thiaporphyrin forms coordinate complexes with Fe(II), 5a Ni(II), 5a Cu(II), 5b,c Pd(II), 5e Rh(III), 5f Li(I), 6 Hg(II) 7 and Ru(II) 9 whereas 21-oxaporphyrin forms complexes with Ni(II), 10 Co(II), 11 Mn(II), 11 Zn(II), 11,12 Cu(II) 13 and Fe(II). 14 The metal coordination chemistry of other heteroporphyrins such as 21-selenaporphyrins and 21-telluraporphyrins has not been explored.…”

Thiaporphyrins: from building blocks to multiporphyrin arrays

“…13 It has been shown in the literature that Ru(II) porphyrin is one of the most important metalloporphyrin building blocks which is involved in construction of several non-covalent porphyrin arrays. 2 Interestingly, although Ru(II) complexes of 21-thiaporphyrin 43 and 21,23-dithiaporphyrin 44 were reported in the literature, no thiaporphyrin-based self assembled porphyrin oligomers were synthesized. However the free base thiaporphyrins containing meso-pyridyl and meso-hydroxyphenyl groups were used We reported the synthesis of unsymmetrical non-covalent dyads 65a-65d assembled using Ru-pyridine "N" interactions.…”

Synthesis of carboxylate functionalized A3B and A2B2 thiaporphyrins and their application in dye-sensitized solar cells

“…22 Although these thiaporphyrins possess interesting optical properties, surprisingly their use in DSSCs is very uncommon. 23 Following our interest in thiaporphyrins and their metal complexes, 24,25 we have recently shown that these heteroporphyrins can be successfully applied as sensitizers in DSSCs. 26,27 Thiaporphyrin N3S-ECA, with an ethynylphenyl linker at a meso position and a carboxylic acid as the terminal anchoring group, gave very low efficiency with an iodine/triiodide redox electrolyte.…”