Control of optically active structure of thioether-phthalocyanine aggregates by chiral Pd(II)-BINAP complexes in toluene and at the toluene/water interface.
The Pd(II)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP)-mediated chiral assembly of thioether-derivatised phthalocyanatomagnesium(II) compounds (MgPc(SR)8, SR is benzylthio (SBz) or benzhydrylthio (Bh)) was formed in toluene and at the toluene/water interface, and investigated by means of UV-Vis absorption and circular dichroism (CD) spectroscopy combined with the centrifugal liquid-membrane (CLM) devise. Interfacial tension measurements indicated that, in the presence of PdSO4 in the aqueous phase, BINAP ligand adsorbed as a monolayer forming Pd(II)BINAP2+ complex at the toluene/water interface. UV-Vis absorption spectrum of MgPc(SR)8 in the Q-band region was blue-shifted in toluene upon addition of [Pd(II)BINAP]Cl2, but red-shifted at the toluene/water interface when Pd(II)BINAP2+ was formed at the interface. These results suggested that MgPc(SR)8-Pd(II)BINAP complex formed H-aggregate (face-to-face type) in toluene solution and J-aggregate (end-to-end type) at the toluene/water interface, respectively. Moreover, the specific bisignate CD spectral pattern in both systems indicated that the aggregates of MgPc(SR)8-Pd(II)BINAP complexes were chirally twisted, well controlled by the chirality of BINAP ligand. Very interestingly, the morphology of MgPc(SBz)8-Pd(II)BINAP and MgPc(SBh)8-Pd(II)BINAP aggregates formed at the toluene/water interface were significantly different as the rodlike and the ribbonlike crystalline structure, respectively, as observed by a scanning electron microscopy (SEM). On the basis of these experimental results, we proposed schematic molecular models of the chiral aggregates of MgPc(SR)8-Pd(II)BINAP complexes and demonstrated the specific role of the toluene/water interface.
Adachi
Kenta
K
Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.
Chayama
Kenji
K
Watarai
Hitoshi
H
D002942:Circular Dichroism; D019281:Dimerization; D007211:Indoles / Q000737:chemistry* / Q000378:metabolism; D054833:Isoindoles; D008956:Models, Chemical; D008958:Models, Molecular; D009281:Naphthalenes / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013237:Stereoisomerism; D013440:Sulfides / Q000737:chemistry* / Q000378:metabolism; D013499:Surface Properties; D014050:Toluene / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
C406943:BINAP, 2-naphthol; D007211:Indoles; D054833:Isoindoles; D009281:Naphthalenes; D013440:Sulfides; D014867:Water; D014050:Toluene; D010165:Palladium; C013647:phthalocyanine