Pouke flogistonske teorije Raos, Nenad
Kemija u industriji; časopis kemičara i tehnologa Jugoslavije,
5/2015, Letnik:
64, Številka:
5-6
Journal Article
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► Two models for the estimation of stability of lanthanide complexes were developed. ► Models are suitable at low and high mass fractions of dioxane in water. ► Models enable ...simultaneous estimation of K1 in different water–dioxane mixtures. ► Models allow simultaneous estimation of K1 of complexes of different metals.
We developed two models for the estimation of stability constants in dioxane–water mixtures of mono-complexes of lanthanides (La3+, Ce3+, Pr3+, and Nd3+) with carboxylic acids (ethanoic, propanoic, and butanoic). The first, linear model proved suitable for the prediction of logK1 at low mass fractions of dioxane, w=0–20% (r=0.981, S.E.=0.06), whereas the second, quadratic model, yielded better results at higher fractions, w=40–60% (r=0.980, S.E.=0.10).
Three sets of flavonoid derivatives (N=32, 40, and 74) and logarithms of their dissociation constants (log Kd) that describe flavonoid affinity toward P-glycoprotein were modelled using six ...connectivity indices. The best results were obtained with the zero-order valence molecular connectivity index (
) for all three sets. Standard errors of the calibration models were around 0.3, and of the constants from the test sets even a little lower, 0.22 and 0.24. Despite using only one descriptor, our model proved better in internal (cross-validation) and especially in external (test set) statistics than much more demanding methods used in previous 3D QSAR modelling.
Using molecular graph theory we studied the binding of NSFRY-NH
and 12 related pentapeptide amides to Cu(II) as a model system for atrial natriuretic factor (ANF) peptide interactions with copper. ...Linear regression models based on the valence connectivity index of the 3
order (
) reproduced experimental stability constants (log β) for 1N, 2N, 3N, and 4N coordinated complexes with the standard error of 0.30-0.39 log β units. We developed separate models for seven tyrosinic (N=28) and five non-tyrosinic peptides (N=20), and a common model for both kinds of peptides (N=48) with an indicator (dummy) variable. The results indicate additional aromatic stabilisation in 4N complexes due to metal cation-π interactions with tyrosine but not with the phenylalanine residue. We have also amended the log K and log K* values to correct miscalculations published by Janicka-Klos et al. in 2013
Služeći se teorijom molekularnih grafova istraživali smo vezivanje NSFRY-NH
i 12 srodnih pentapetidnih amida za Cu(II) kao modelnog sustava za interakciju bakra s peptidnom molekulom atrijalnog natriuretičkog faktora (ANF). Modeli linarne regresije temeljeni na valencijskom indeksu povezanosti trećega reda (
) reproducirali su eksperimentalnu konstantu stabilnosti (log β) za komplekse koordinacije 1N, 2N, 3N i 4N sa standardnom pogreškom u rasponu od 0,30 do 0,39 log β jedinica. Razvili smo odvojene modele za sedam tirozinskih (N=28) i pet netirozinskih (N=20) peptida te skupni model s indikatorskom varijablom za obje vrste peptida (N=48). Rezultati upućuju na dodatnu aromatsku stabilizaciju u kompleksima vrste 4N zbog interakcija kationa s π-orbitalama tirozinskog ostatka, ali ne i fenilalaninskoga. Ispravili smo i pogrešne vrijednosti log K i log K* nastale omaškom u radu Anne Janicka-Klos i sur. 2013.
Using molecular graph theory we studied the binding of NSFRY-NH^sub 2^ and 12 related pentapeptide amides to Cu(II) as a model system for atrial natriuretic factor (ANF) peptide interactions with ...copper. Linear regression models based on the valence connectivity index of the 3rd order (^sup 3^χ^sup v^) reproduced experimental stability constants (log β) for 1N, 2N, 3N, and 4N coordinated complexes with the standard error of 0.30-0.39 log β units. We developed separate models for seven tyrosinic (N=28) and five non-tyrosinic peptides (N=20), and a common model for both kinds of peptides (N=48) with an indicator (dummy) variable. The results indicate additional aromatic stabilisation in 4N complexes due to metal cation-π interactions with tyrosine but not with the phenylalanine residue. We have also amended the log K and log K* values to correct miscalculations published by Janicka-Klos et al. in 2013.
Using molecular graph theory we studied the binding of NSFRY-NH sub( 2) and 12 related pentapeptide amides to Cu(II) as a model system for atrial natriuretic factor (ANF) peptide interactions with ...copper. Linear regression models based on the valence connectivity index of the 3rd order ( super( 3) chi super( v)) reproduced experimental stability constants (log beta ) for 1N, 2N, 3N, and 4N coordinated complexes with the standard error of 0.30-0.39 log beta units. We developed separate models for seven tyrosinic (N=28) and five non-tyrosinic peptides (N=20), and a common model for both kinds of peptides (N=48) with an indicator (dummy) variable. The results indicate additional aromatic stabilisation in 4N complexes due to metal cation- pi interactions with tyrosine but not with the phenylalanine residue. We have also amended the log K and log K* values to correct miscalculations published by Janicka-Klos et al. in 2013.
We developed a purely empirical model for the estimation of stability constants of acetate mono-complexes of four lanthanides (La3+, Nd3+, Gd3+, and Yb3+) at different ionic strengths ...(I=0.1–2.0molkg−1) and temperatures (t=25–70°C). The standard errors, S.E., were 0.09, 0.05, 0.06, and 0.07, for La3+, Nd3+, Gd3+, and Yb3+ complex, respectively. We also developed common model for the complexes of all metals studied (S.E.=0.11), which enables prediction of log K1 for a metal, at different conditions, knowing the value of its constant measured at only one ionic strength and temperature.
► We developed an empirical model for the estimation of K1 of lanthanide complexes. ► K1 of acetate complexes with La3+, Nd3+, Gd3+, and Yb3+ was modeled. ► Model allows simultaneous estimation of K1 of complexes of different metals. ► Model enables estimation of K1 at I=0.1–2.0molkg−1 and t=25–70°C.
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