Reactivity of aqua coordinated monoporphyrinate lanthanide complexes: synthetic, structural and photoluminescent studies of lanthanide porphyrinate dimers

Abstract

Dimerization of monoporphyrinate lanthanide complexes [Yb(Por)(H(2)O)(3)]Cl, (Por = TTP(2-), TMPP(2-) and TPP(2-)) in the presence of sterically hindered tripodal ligand, zinc Schiff-base, dilute HCl, K(2)CO(3) solution, 4,4'-bipyridine (bipy), and basic 8-hydroxyquinaldine (HQ) solution was observed in CH(2)Cl(2) at room temperature. Six neutral dimeric lanthanide porphyrinate complexes, [Yb(TTP)(mu-OH)](2)(mu-THF) (1), [Yb(TMPP)(mu-OH)(H(2)O)](2) (2), [Yb(TPP)(mu-OH)(mu-H(2)O)](2) (4), [Yb(TMPP)(mu-Cl)(H(2)O)](2) (5), [Yb(TMPP)(mu-OH)](2)(THF) (6) and [Yb(TPP)](2)(mu-OH)(mu-Q) (7), were obtained. X-Ray diffraction studies showed that for the dimers, the two lanthanide ions were bridged by OH(-), Cl(-) or H(2)O. Photoluminescent studies showed that the porphyrinate dianion acted as an antenna, transferred its absorbed visible energy to the lanthanide ion and enabled the latter emitting in the near-infrared (NIR) region. In general, the NIR emission is more intense for the dimers than for the monomers, and the NIR emission intensity decreases as the number of O-H oscillators present in the molecule increases.

Microcalorimetric and Spectroscopic Investigation of the Antibacterial Properties of Cationic Ytterbium(III)–Porphyrin Complexes Lacking Charged Peripheral Groups

“…All these phenomena indirectly suggest an inhibitory effect of the two cationic porphyrinates, attributed to their high reactivities. The porphyrin complexes 1 and 2 are more reactive than normal porphyrins, owing to the ready displacement of the centrally coordinated H 2 O molecules [24], Yb(TMP) (1) possessing higher antibacterial activity than Yb(TTP) (2). Considering the structures of these complexes, we propose that the more-hydrophilic 4-methoxyphenyl groups of 1 have a higher affinity to organs than the p-tolyl ( ¼ 4-methylphenyl) groups in 2, which may result in differential inhibitory properties.…”

Near-infrared emitting lanthanide complexes of porphyrin and BODIPY dyes

“…The counter ion Cl − did not bind to Ln 3+ ions. It was found that the three water molecules in [Ln(Por)(H 2 O) 3 ]Cl were quite labile and readily reacted with solvents, such as tetrahydrofuran (THF) or OH − , to form dimers [19]. Three water molecules can also be replaced by tridentate ligands as shown in the following equation [17,[19][20][21]:…”

Antibacterial Effects of a Monoporphyrinato Ytterbium(III) Complex and Its Free Components on Staphylococcus aureus as Determined by Stop‐Flow Microcalorimetry

“…Finally, the synergetic function of [Yb(TMP)] þ (2) on S. aureus could be due to the unique structure of this complex, in which the aqua molecules around Yb III can be easily displaced [4], the porphyrin ring being compatible with the biological structure. All these factors rationalize why 2 has a higher affinity to the bacterial cell membrane than Yb 3 þ and H 2 TMP alone.…”

“…However, lanthanide -porphyrin complexes possess unique chemical structures, which depends on the coordinated Ln III ions. Here, coordinated H 2 O molecules can be easy displaced, which is why cationic lanthanide porphyrins are more reactive than transition-metal porphyrins [4]. Lanthanide ions play an important role in biochemistry.…”