Determination of descriptors for organosilicon compounds by gas chromatography and non-aqueous liquid–liquid partitioning

Ahmed, Hamid; Poole, Colin F.; Kozerski, Gary E.

doi:10.1016/j.chroma.2007.09.001

Cited by 112 publications

(51 citation statements)

References 42 publications

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“…Several review articles describing the various methods used to determine liquid-liquid partition coefficients and especially K o/w appeared recently. [37][38][39][40] Names of these compounds and their experimental n-octanol-water partition coefficients are shown in Table 1. As can be seen, this set contains in total namely 61 n-octanol-water partition coefficients data.…”

Section: Data Setmentioning

confidence: 99%

QSPR study of partition coefficient (Ko/w) of some organic compounds using radial basic function-partial least square (RBF-PLS)

Goudarzi¹,

Goodarzi²

2010

J. Braz. Chem. Soc.

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Neste trabalho, nós introduzimos um novo método da função de base radial por regressão de mínimos quadrados (RBF-PLS) com elevada exatidão e precisão nos estudos quantitativos da relação entre a estrutura-propriedade de compostos orgânicos (QSPR). Três métodos QSPR foram comparados para a predição dos coeficientes de partição no sistema n-octanol-água (K o/w ) (de alguns compostos orgânicos). A regressão linear múltipla (MLR), a regressão parcial dos mínimos quadrados (PLS) e a regressão base radial com funções pelo método de mínimos quadrados (RBF-PLS) foram empregadas para construir os modelos lineares e não-lineares e predizer o valor de K o/w . Os descritores teóricos foram calculados por Dragon e por Gaussian 98 e foram explorados pelas regressões parciais, codificando diferentes aspectos topológicos, geométricos e eletrônicos das estruturas moleculares. A raiz quadrada dos erros médios previstos (RMSEP) para as etapas de testes e da previsão teórica por modelos de MLR, de PLS e de RBF-PLS foram 0,4022; 0,4128; 0,3050; 0,3564; 0,0364 e 0,0533 respectivamente. Também, o erro padrão relativo previsto (RSEP) para os testes e de previsão teórica por MLR, PLS e RBF-PLS foram de 13,24; 13,60; 10,04; 11,74; 1,197 e 1,757 respectivamente. Os dados mostram que o RBF-PLS produziu resultados melhores do que PLS e MLR.In this work, we introduce a new method ability radial basic function-partial least square (RBF-PLS) with high accuracy and precision in QSPR studies. Three quantitative structure-propertty relationship (QSPR) methods have been compared for the prediction of n-octanol-water partition coefficients (K o/w ) of some organic compounds. The multiple linear regressions (MLR), partial least square (PLS) and radial basis function-partial least squares (RBF-PLS) models were employed to construct linear and nonlinear models to predict of K o/w . The theoretical descriptors that calculated by Dragon and Gaussian 98 were explored by stepwise regressions, encoding different aspects of the topological, geometrical and electronic molecular structures. The root means square error of prediction (RMSEP) for training and prediction sets by MLR, PLS and RBF-PLS models were 0.4022, 0.4128, 0.3050, 0.3564, 0.0364 and 0.0533, respectively. Also, the relative standard error of prediction (RSEP) for training and prediction sets by MLR, PLS and RBF-PLS models were 13. 24, 13.60, 10.04, 11.74, 1.197 and 1.757 respectively. The resultant data explained that RBF-PLS produced better results than PLS and MLR.

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Section: Data Setmentioning

confidence: 99%

QSPR study of partition coefficient (Ko/w) of some organic compounds using radial basic function-partial least square (RBF-PLS)

Goudarzi¹,

Goodarzi²

2010

J. Braz. Chem. Soc.

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“…The V 3 D 3 monomer ads/des measurements are performed in the deposition setup directly on c-Si substrates by monitoring the adsorbed monomer thickness by means of in situ SE measurements. The used optical model is composed of: 1) silicon substrate; 2) SiO 2 native oxide layer (1.5-2 nm); 3) V 3 D 3 monomer layer, modeled with the Cauchy dispersion being the thickness the only fit parameter and the monomer refractive index fixed to the constant value of 1.422 at 589.3 nm, 32 as reported in literature. The choice of studying the surface monomer adsorption by monitoring the changes in thickness is motivated, as will be shown in Sec.…”

Section: Film Growth and Monomer Ads/des Isotherms Studiesmentioning

confidence: 99%

Initiated-chemical vapor deposition of organosilicon layers: Monomer adsorption, bulk growth, and process window definition

Aresta

Palmans

Sanden

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Organosilicon layers have been deposited from 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane (V 3 D 3 ) by means of the initiated-chemical vapor deposition (i-CVD) technique in a deposition setup, ad hoc designed for the engineering of multilayer moisture permeation barriers. The application of Fourier transform infrared (FTIR) spectroscopy shows that the polymerization proceeds through the scission of the vinyl bond and allows quantifying the degree of conversion of vinyl groups, which is found to be larger than 80% for all the deposited layers. In situ real-time spectroscopic ellipsometry (SE) allows following all the i-CVD growth stages, i.e., from the initial monomer adsorption to the layer bulk growth. Finally, the combination of SE and FTIR has allowed defining the process window for the deposition of stable and highly cross-linked poly(V 3 D 3 ) layers by tuning a key process parameter, i.e. the surface monomer adsorption.

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“…For compounds of low water solubility, or compounds that react with water, predominantly aqueous biphasic systems are of limited use. For example, water-based biphasic systems are widely used for the determination of descriptors for use in the solvation parameter model [5], but for the reasons stated above, they where found to be unsuitable for the determination of descriptors for organosilicon compounds [6,7]. An attractive feature of predominantly aqueous biphasic systems for descriptor measurements is the availability of complementary systems with large values for s, a, and b system constants (defined later), which facilitate the calculation of solute descriptors for use in the solvation parameter model.…”

Section: Introductionmentioning

confidence: 99%

“…The biphasic system n-heptane-ethylene glycol was shown to be suitable for estimating hydrogen-bonding descriptors for peptides [17]. The biphasic systems n-hexane-acetonitrile, n-heptane-N,Ndimethylformamide, and n-heptane-2,2,2-trifluoroethanol were used together with chromatographic retention factors to determine a complete set of descriptors for organosilicon compounds [6,7] and for a variety of other compounds difficult to study using water-based partition systems [23].…”

Section: Introductionmentioning

confidence: 99%

Model for the partition of neutral compounds between n‐heptane and formamide

Karunasekara

Poole

2010

J of Separation Science

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Partition coefficients for 84 varied compounds were determined for n-heptane-formamide biphasic partition system and used to derive a model for the distribution of neutral compounds between the n-heptane-rich and formamide-rich layers. The partition coefficients, log K(p), were correlated through the solvation parameter model giving log K(p)=0.083+0.559E-2.244S-3.250A-1.614B+2.387V with a multiple correlation coefficient of 0.996, standard error of the estimate 0.139, and Fisher statistic 1791. In the model, the solute descriptors are excess molar refraction, E, dipolarity/polarizability, S, overall hydrogen-bond acidity, A, overall hydrogen-bond basicity, B, and McGowan's characteristic volume, V. The model is expected to be able to estimate further values of the partition coefficient to about 0.13 log units for the same descriptor space covered by the calibration compounds (E=-0.26-2.29, S=0-1.93, A=0-1.25, B=0.02-1.58, and V=0.78-2.50). The n-heptane-formamide partition system is shown to have different selectivity to other totally organic biphasic systems and to be suitable for estimating descriptor values for compounds of low water solubility and/or stability.

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Determination of descriptors for organosilicon compounds by gas chromatography and non-aqueous liquid–liquid partitioning

Cited by 112 publications

References 42 publications

QSPR study of partition coefficient (Ko/w) of some organic compounds using radial basic function-partial least square (RBF-PLS)

QSPR study of partition coefficient (Ko/w) of some organic compounds using radial basic function-partial least square (RBF-PLS)

Initiated-chemical vapor deposition of organosilicon layers: Monomer adsorption, bulk growth, and process window definition

Model for the partition of neutral compounds between n‐heptane and formamide

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