Band-target entropy minimization (BTEM): An advanced method for recovering unknown pure component spectra. application to the FTIR spectra of unstable organometallic mixtures
Band-target entropy minimization (BTEM): An advanced method for recovering unknown pure component spectra. application to the FTIR spectra of unstable organometallic mixtures
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DOI：
10.1021/om0108752
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发表时间：
2002-04-29
期刊：
影响因子：
2.8
通讯作者：
Garland, M
中科院分区：
文献类型：
--
作者：
Chew, W;Widjaja, E;Garland, M
用新发展的带靶熵最小化（BTEM）算法对Rh-4（CO）（12）/Rh-6（CO）（16）混合物的实验FTIR数据进行了测试，以恢复组成络合物的纯组分光谱。非重叠桥接羰基区域中的条带以及高度重叠的末端羰基区域中的条带作为保留的目标。在观测的矢量空间分解中识别波段，这是解开纯组分光谱叠加的关键的第一步。在这两种情况下，保留了目标条带，并获得了Rh-4（CO）（12）和Rh-6（CO）（16）的异常准确的全光谱估计值。由于在BTEM中使用的结构，增强的信号噪声特性的结果，并且从改变频带位置和改变频带形状所引起的光谱非线性基本上被消除。对于实验者来说，BTEM的实用性源于其直接的一次一个光谱的光谱重建方法，该方法由目标区域的选择指导。因此，BTEM似乎特别适用于具有高度局部化特征的光谱学：即，FTIR，拉曼，等的BTEM算法是如此有用，从悬浮颗粒的Rh 6（CO）16的微小存在的光谱图案可以重建。事实上，Rh-4（CO）（12）、Rh-6（CO）（16）和Rh-6（CO）（16）固体的积分吸光度仅占约10%。实验观察值的0.3%、0.09%和0.04%。将新的BTEM算法与SIMPLISMA、IPCA和OPA-ALS等算法进行了比较。后者要么失败与目前的数据集或无法产生类似的质量重建光谱BTEM。这种新的算法具有相当大的承诺，原位光谱反应数据的分析，如所产生的，复杂的有机金属的有机合成，其中绝对没有先验信息的成分/中间体是可用的。
A newly developed band-target entropy minimization (BTEM) algorithm was tested on experimental FTIR data of Rh-4(CO)(12)/Rh-6(CO)(16) Mixtures in order to recover the pure component spectra of the constituent complexes. Bands in the nonoverlapping bridging carbonyl region as well as bands in the highly overlapping terminal carbonyl region were targeted for retention. The bands are identified in the vector-space decomposition of the observations, a crucial first step in untangling the superposition of the pure component spectra. In both cases, the targeted band was retained, and exceptionally accurate whole spectral estimates of Rh-4(CO)(12) and Rh-6(CO)(16) were obtained. Due to the constructs used in BTEM, enhanced signal-to-noise characteristics result, and spectral nonlinearities arising from changing band positions and changing band shapes are essentially eliminated. For the experimentalist, the utility of BTEM arises from its direct one-spectrum-at-a-time spectral reconstruction approach-which is guided by the choice of the targeted region. As such, BTEM appears particularly applicable to spectroscopy possessing highly localized features: i.e., FTIR, Raman, etc. The BTEM algorithm is so useful that the spectral pattern from the minute presence of suspended particles of Rh6(CO)16 could be reconstructed. Indeed, the integrated absorbance of Rh-4(CO)(12), Rh-6(CO)(16), and Rh-6(CO)(16) solids account for only ca. 0.3, 0.09, and 0.04% of the experimental observations. The new BTEM algorithm was compared to other algorithms such as SIMPLISMA, IPCA, and OPA-ALS. The latter either fail with the present data set or are unable to produce reconstructed spectra of similar quality to BTEM. This new algorithm holds considerable promise for the analysis of in-situ spectroscopic reaction data such as those arising in, complex organometallic an organic syntheses, where absolutely no a priori information about the constituents/intermediates is available.