Chromium tricarbonyl complexes η6-bonded to 3-amino-9-ethylcarbazole at either the NH2-substituted aryl ring (1) or the unsubstituted aryl ring (2) have been synthesized and their UV-visible absorption spectra determined. In comparison to 2, 1 causes a subtle blue shift in the metal-to-ligand charge-transfer band along with spectral shape changes due to electron transfer from the NH2 substituent to the Cr(CO)3 center.

A novel experimental approach, based on time-resolved two-dimensional (2D) ATR-FTIR spectroscopy has been used to study water diffusion behavior of novolac epoxy resins cured with novolac resin and novolac acetate resin named as EP and EPA, respectively. The diffusion coefficients calculated by a nonlinear curve fitting are quite consistent with the results of gravimetric analysis. In 2D-IR spectra, the splitting of the water OH vibration band at 2800-3700 and 1500-1800cm-1 shows that there are two different states of water in epoxy networks, in which one could be confined into free volume (microvoids) or molecularly dispersed with less hydrogen-bonding (bulk dissolved), while the other could be attributed to bound water forming strong hydrogen-bonding with hydrophilic groups of epoxy networks. The sequential order of intensity changes of the two water bands elucidates that, in the process of water diffusion into epoxy networks, water molecules first bind with specific hydrophilic groups as bound water and then diffuse into free volume (microvoids) or molecularly dispersed with less hydrogen-bonding (bulk dissolved). The wavenumber difference of OH vibration band appearing from bound water between EP and EPA indicates that water molecules form much stronger hydrogen-bonding with EP networks than with EPA networks.

Two-dimensional correlation spectroscopy has been applied to study PMPCS (poly{2,5-bis[(4- methoxyphenyl)-oxycarbonyl]styrene}), a representative example of mesogen-jacketed liquid crystalline polymers. With the precise analysis of a series of Fourier transform infrared (FTIR) spectra of PMPCS recorded at varied temperatures, a reasonable mechanism of the development of liquid crystalline (LC) phase is proposed. Before the phase transition, the conformational change of individual side chains occurs sooner than that of the backbone due to the larger motional freedom of the side chains. After the phase transition, however, the readjustment of still somewhat mobile backbone occurs before the ordered, rigid, and mutually interacting side chains. That is, phase transition leading to the LC phase formation brings in a new cooperative restriction of motions to the segments.

A recently developed technique, i.e., two-dimensional infrared (2D IR) correlation spectroscopy, is used to study the thermal behavior of poly(ethylene-co-vinyl alcohol)-graft-poly(-caprolactone), a new synthesized highly grafted copolymer. The use of the 2D IR approach to analyze temperature-dependent spectra collected in situ during the temperature elevation process effectively enhanced the spectral resolution and revealed details on the hydrogen bonding and conformational change which are not easily detected in the traditional one-dimensional spectra. The sequence of the spectral changes of different OH and CH2 fundamental vibrations during heating the polymer was inferred from the signs of the asynchronous peaks. Evidence that the conformational changes of the methylene groups precede the loosening of hydrogen bonds is provided.

Raman spectra of a polythiophene film measured over a temperature range 298-98K were analyzed using generalized two-dimensional correlation spectroscopy. In the 1600-1250cm-1 region, the asynchronicity of the bands indicates the existence of different species in the investigated polythiophene sample. At least four distinct bands at 1485, 1454, 1418, and 1360cm-1 were identified. Among them, the band at 1454cm-1, attributed to the neutral species of PTh, is found to be sensitive to the temperature-induced structural changes of the polythiophene film, while the bands of the oxidized species are less sensitive to the temperature change during the cooling process.