Photophysical investigation of the degree of dispersion of aqueous colloidal clay

Abstract

No. Tetra-n-butylammonium chloride, 1112-67-0; tetramethylammonium chloride, 75-57-0; tetraethylammonium chloride, 56-34-8; aluminum(III) chloride, 7446-70-0; sodium hydroxide, 1310-73-2; tris(bipyridine)ruthenium, 74391-32-5; pyrene, 129-00-0; oxygen, 7782-44-7.

The ‘size matching rule’ in di-, tri-, and tetra-cationic charged porphyrin/synthetic clay complexes: effect of the inter-charge distance and the number of charged sites

“…A similar bathochromic shift of the Soret band has been reported in the case of H 2 TMPyP with Laponite [12,13]. These reports suggested that enhanced p-conjugation and the electron withdrawing effect of the pyridinium group, due to a flattening of the TMPyP on the clay, induce the spectral change.…”

Photochemical Energy Transfer of Cationic Porphyrin Complexes on Clay Surface

“…[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] However, little is known about photochemical reactions involving such complexes. Recently, we have developed a new technique for the conformational and orientational control of dye adsorption on clay surfaces.…”

Adsorption characteristics of a cationic porphyrin on nanoclay at various pH

“…It has been shown that porphyrin adsorption to various surfaces; including synthetic smectite clays, induce a rotation of the phenyl substituents from a perpendicular to a more parallel orientation related to the porphine ring. This leads to a ''flattening" of the molecule where the core p-electrons can be further delocalized into the substituent rings, causing a red shift of the Soret and Q-bands [9,10,17,24]. The combination of the loading vs. CEC results and the observed red shifts indicated that individual TMAP molecules adsorbed without aggregation onto natural montmorillite clay in a ''flattened" orientation at low, and high pH.…”

“…Studies of the adsorption and interaction of various porphyrins with solid interfaces, such as the synthetic clay Sumecton SA, have revealed various shifts in porphyrin UV-vis absorption spectra [3,4,9,17], interclay spacing distance [3,18,19], and porphyrin ring distortion [9,[20][21][22] illustrating the multifaceted surface interactions of these molecules (see Takagi et al for a recent review [2]). For the most part studies have been performed in pure distilled water; however as porphyrin-nanoclay constructs are attractive in various nanotechnology and biology applications their adsorption behavior in buffered aqueous solutions at various pHs is of interest.…”