Microenvironmental effects on equilibrium and photoredox chemistry of bromo complexes in reverse micelles

O. Horváth, Tamás Marosvölgyi, József Vörös

Research output: Article

2 Citations (Scopus)

Abstract

Kinetically labile bromo complexes are formed with main-group metal ions of s2 and s0 electron configurations both in homogeneous aqueous solutions and in water droplets inside reverse micelles. The local concentration of the Br- ligand in the inner water pool can reach extremely high values if it is the counterion of the surfactant as in the case of cetyltrimethylammonium bromide (CTAB) dissolved in CH2Cl 2 or CHCl3. Bromo complexes of the possibly highest coordination number are formed with Sb3+ (n = 6), Bi3+ (n = 6), and Pb2+ (n = 4) in these systems at low water to surfactant molar ratio, W. Irradiation of these complexes results in ligand-to-metal charge-transfer (LMCT) reactions generating Br3 - as an end product. The quantum yields for the overall processes dramatically decrease upon increasing W in the CTAB/CHCl3 systems. This phenomenon can be attributed to a hydration effect enhancing the efficiency of the vibrational energy dissipation. In homogeneous aqueous solution of 0.1 M Br-, the predominant coordination number of bromomercurate(II) complexes is 4, while inside aerosol-OT reverse micelles (at the same local concentration of the ligand) it is only 3, owing to the dehydration of the reactants of the same charge in the complex equilibrium. Upon UV excitation, these complexes also undergo a LMCT reaction producing elemental mercury and Br3 - as end products.

Original languageEnglish
Pages (from-to)17-23
Number of pages7
JournalProgress in Colloid and Polymer Science
Volume125
DOIs
Publication statusPublished - 2004

Fingerprint

Micelles
micelles
Ligands
chemistry
ligands
coordination number
Surface-Active Agents
Water
Charge transfer
bromides
Surface active agents
Metals
Dioctyl Sulfosuccinic Acid
surfactants
charge transfer
water
aqueous solutions
Mercury (metal)
Quantum yield
products

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Chemistry (miscellaneous)
  • Colloid and Surface Chemistry
  • Polymers and Plastics

Cite this

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title = "Microenvironmental effects on equilibrium and photoredox chemistry of bromo complexes in reverse micelles",
abstract = "Kinetically labile bromo complexes are formed with main-group metal ions of s2 and s0 electron configurations both in homogeneous aqueous solutions and in water droplets inside reverse micelles. The local concentration of the Br- ligand in the inner water pool can reach extremely high values if it is the counterion of the surfactant as in the case of cetyltrimethylammonium bromide (CTAB) dissolved in CH2Cl 2 or CHCl3. Bromo complexes of the possibly highest coordination number are formed with Sb3+ (n = 6), Bi3+ (n = 6), and Pb2+ (n = 4) in these systems at low water to surfactant molar ratio, W. Irradiation of these complexes results in ligand-to-metal charge-transfer (LMCT) reactions generating Br3 - as an end product. The quantum yields for the overall processes dramatically decrease upon increasing W in the CTAB/CHCl3 systems. This phenomenon can be attributed to a hydration effect enhancing the efficiency of the vibrational energy dissipation. In homogeneous aqueous solution of 0.1 M Br-, the predominant coordination number of bromomercurate(II) complexes is 4, while inside aerosol-OT reverse micelles (at the same local concentration of the ligand) it is only 3, owing to the dehydration of the reactants of the same charge in the complex equilibrium. Upon UV excitation, these complexes also undergo a LMCT reaction producing elemental mercury and Br3 - as end products.",
keywords = "Bromo complexes, Ligand-to-metal charge-transfer reaction, Main-group metal ions, Photoredox chemistry, Reverse micelles",
author = "O. Horv{\'a}th and Tam{\'a}s Marosv{\"o}lgyi and J{\'o}zsef V{\"o}r{\"o}s",
year = "2004",
doi = "10.1007/b13488",
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pages = "17--23",
journal = "Progress in Colloid and Polymer Science",
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T1 - Microenvironmental effects on equilibrium and photoredox chemistry of bromo complexes in reverse micelles

AU - Horváth, O.

AU - Marosvölgyi, Tamás

AU - Vörös, József

PY - 2004

Y1 - 2004

N2 - Kinetically labile bromo complexes are formed with main-group metal ions of s2 and s0 electron configurations both in homogeneous aqueous solutions and in water droplets inside reverse micelles. The local concentration of the Br- ligand in the inner water pool can reach extremely high values if it is the counterion of the surfactant as in the case of cetyltrimethylammonium bromide (CTAB) dissolved in CH2Cl 2 or CHCl3. Bromo complexes of the possibly highest coordination number are formed with Sb3+ (n = 6), Bi3+ (n = 6), and Pb2+ (n = 4) in these systems at low water to surfactant molar ratio, W. Irradiation of these complexes results in ligand-to-metal charge-transfer (LMCT) reactions generating Br3 - as an end product. The quantum yields for the overall processes dramatically decrease upon increasing W in the CTAB/CHCl3 systems. This phenomenon can be attributed to a hydration effect enhancing the efficiency of the vibrational energy dissipation. In homogeneous aqueous solution of 0.1 M Br-, the predominant coordination number of bromomercurate(II) complexes is 4, while inside aerosol-OT reverse micelles (at the same local concentration of the ligand) it is only 3, owing to the dehydration of the reactants of the same charge in the complex equilibrium. Upon UV excitation, these complexes also undergo a LMCT reaction producing elemental mercury and Br3 - as end products.

AB - Kinetically labile bromo complexes are formed with main-group metal ions of s2 and s0 electron configurations both in homogeneous aqueous solutions and in water droplets inside reverse micelles. The local concentration of the Br- ligand in the inner water pool can reach extremely high values if it is the counterion of the surfactant as in the case of cetyltrimethylammonium bromide (CTAB) dissolved in CH2Cl 2 or CHCl3. Bromo complexes of the possibly highest coordination number are formed with Sb3+ (n = 6), Bi3+ (n = 6), and Pb2+ (n = 4) in these systems at low water to surfactant molar ratio, W. Irradiation of these complexes results in ligand-to-metal charge-transfer (LMCT) reactions generating Br3 - as an end product. The quantum yields for the overall processes dramatically decrease upon increasing W in the CTAB/CHCl3 systems. This phenomenon can be attributed to a hydration effect enhancing the efficiency of the vibrational energy dissipation. In homogeneous aqueous solution of 0.1 M Br-, the predominant coordination number of bromomercurate(II) complexes is 4, while inside aerosol-OT reverse micelles (at the same local concentration of the ligand) it is only 3, owing to the dehydration of the reactants of the same charge in the complex equilibrium. Upon UV excitation, these complexes also undergo a LMCT reaction producing elemental mercury and Br3 - as end products.

KW - Bromo complexes

KW - Ligand-to-metal charge-transfer reaction

KW - Main-group metal ions

KW - Photoredox chemistry

KW - Reverse micelles

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