Steplike Response Behavior of a New Vapochromic Platinum Complex Observed with Simultaneous Acoustic Wave Sensor and Optical Reflectance Measurements
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- 作者：Jay W. Grate ; Leslie K. Moore ; Daron E. Janzen ; David J. Veltkamp ; Steve Kaganove ; Steven M. Drew ; and Kent R. Mann
- 刊名：Chemistry of Materials
- 出版年：2002
- 出版时间：March 2002
- 年：2002
- 卷：14
- 期：3
- 页码：1058 - 1066
- 全文大小：286K
- 年卷期：v.14,no.3(March 2002)
- ISSN：1520-5002
文摘
We report the synthesis and characterization of a new vapochromic platinum compound,[Pt(CN-cyclododecyl)4][Pt(CN)4]. This compound is stable to 120 
C and reversibly sorbsthree water molecules per formula unit at room temperature when it is exposed to 100%relative humidity. Dramatic changes in absorption and emission spectra are observed inresponse to water uptake. The vapor response characteristics of this material were furtherinvestigated by simultaneous optical reflectance and quartz crystal microbalance (QCM)measurements, using water as the test vapor. The sensing film on the QCM consisted of amixture of the solid vapochromic powder dispersed in a hydrophobic vapor permeablepolymer. The polymer was incorporated as a binder to adhere the sensing material to theQCM surface. Reflectance measurements were taken from the film on the QCM surface usinga bifurcated fiber optic bundle incorporated into the flow cell. The vapor sorptioncharacteristics of the vapochromic compound as determined by the QCM were closelycorrelated with the observed spectral changes. In addition, an unexpected steplike responsewith increasing water vapor concentration was observed, with little water vapor uptake atlow concentrations, followed by a large water uptake with corresponding spectral changes,and then little change with further increases in water vapor concentration. Water vaporuptake as measured by the QCM is in agreement with the bulk gravimetric measurements.The response behavior is rapid (minutes) and reversible. The distinctly nonlinear, steplikeresponse is interpreted as a reversible transition from a nonhydrated form of [Pt(CN-cyclododecyl)4][Pt(CN)4] to a hydrated form with three water molecules per formula unit.
C and reversibly sorbsthree water molecules per formula unit at room temperature when it is exposed to 100%relative humidity. Dramatic changes in absorption and emission spectra are observed inresponse to water uptake. The vapor response characteristics of this material were furtherinvestigated by simultaneous optical reflectance and quartz crystal microbalance (QCM)measurements, using water as the test vapor. The sensing film on the QCM consisted of amixture of the solid vapochromic powder dispersed in a hydrophobic vapor permeablepolymer. The polymer was incorporated as a binder to adhere the sensing material to theQCM surface. Reflectance measurements were taken from the film on the QCM surface usinga bifurcated fiber optic bundle incorporated into the flow cell. The vapor sorptioncharacteristics of the vapochromic compound as determined by the QCM were closelycorrelated with the observed spectral changes. In addition, an unexpected steplike responsewith increasing water vapor concentration was observed, with little water vapor uptake atlow concentrations, followed by a large water uptake with corresponding spectral changes,and then little change with further increases in water vapor concentration. Water vaporuptake as measured by the QCM is in agreement with the bulk gravimetric measurements.The response behavior is rapid (minutes) and reversible. The distinctly nonlinear, steplikeresponse is interpreted as a reversible transition from a nonhydrated form of [Pt(CN-cyclododecyl)4][Pt(CN)4] to a hydrated form with three water molecules per formula unit.