TY - JOUR
T1 - Optical and electrochemical properties and the calculated structure of pentacoordinate aluminum 8-hydroxyquinoline
AU - Bae, Cheolbeom
AU - Saleh Ahammad, A. J.
AU - Lee, Jae Joon
AU - Kwag, Gwanghoon
PY - 2011/7/15
Y1 - 2011/7/15
N2 - In this study we report on the characterization of a series of pentacoordinate aluminum 8-hydroxyquinolines, AlQ2X (X = F, Cl, Br), composed of two 8-hydroxyquinoline (8-HQ) groups and one halogen ligand. These were prepared by reacting 8-hydroxyquinoline and dialkylaluminum halide stoichiometrically. The λmaxs of absorption and emission were in the range of 385-388 and 515-516 nm, respectively, which were similar to AlQ3. The molar absorptivity of AlQ2X is similar regardless of the X group but emission efficiency of AlQ2X is 2-3 fold higher than that of AlQ3 when X = F or Br, but not when X = Cl. This result can be attributed to decreased quenching of energy due to a less steric environment by reducing quinolinate content. The overall molecular orbital structures and the absorption spectra of AlQ2X and AlQ 3 are very similar due to a single quinolinate unit. The value of the potential difference of AlQ2Xs between anodic and cathodic waves (ΔE = 3.12 V) is close to the estimated HOMO-LUMO energy gap (the optical band gap, ΔEoptical ∼ 1240/λmax), 3.19 eV. Detailed optical and electrochemical properties of AlQ2X are discussed.
AB - In this study we report on the characterization of a series of pentacoordinate aluminum 8-hydroxyquinolines, AlQ2X (X = F, Cl, Br), composed of two 8-hydroxyquinoline (8-HQ) groups and one halogen ligand. These were prepared by reacting 8-hydroxyquinoline and dialkylaluminum halide stoichiometrically. The λmaxs of absorption and emission were in the range of 385-388 and 515-516 nm, respectively, which were similar to AlQ3. The molar absorptivity of AlQ2X is similar regardless of the X group but emission efficiency of AlQ2X is 2-3 fold higher than that of AlQ3 when X = F or Br, but not when X = Cl. This result can be attributed to decreased quenching of energy due to a less steric environment by reducing quinolinate content. The overall molecular orbital structures and the absorption spectra of AlQ2X and AlQ 3 are very similar due to a single quinolinate unit. The value of the potential difference of AlQ2Xs between anodic and cathodic waves (ΔE = 3.12 V) is close to the estimated HOMO-LUMO energy gap (the optical band gap, ΔEoptical ∼ 1240/λmax), 3.19 eV. Detailed optical and electrochemical properties of AlQ2X are discussed.
KW - Aluminum 8-hydroxyquinoline
KW - Calculated structure
KW - Electrochemistry
KW - Halogens
KW - Optical property
UR - http://www.scopus.com/inward/record.url?scp=79957815948&partnerID=8YFLogxK
U2 - 10.1016/j.ica.2011.04.001
DO - 10.1016/j.ica.2011.04.001
M3 - Article
AN - SCOPUS:79957815948
SN - 0020-1693
VL - 373
SP - 124
EP - 129
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
IS - 1
ER -