Partial negative surface area

In the CPSA approach, the fundamental molecular properties are the surface area contributions of the positively and negatively charged atoms r and s, SAj and SA , and the associated net atomic charges, Q and Q . The simple partial positive surface area (PPSA) is defined as sum of all positively charged surface areas and is called PPSA-1, and the respective partial negative surface area (PNSA) as sum of all negatively charged surface areas is called PNSA-1 ... 

The log Kow, Jurs-PNSA-2 (Jurs-partial negative surface area-2) and Jurs-RPCS (Relative Positive Change Surface) reflect the hydrophobicity (log Kow) (Leffler and Grunwald 1963) and... 

Keseru [35] used literature data on 55 compounds to train a QSAR model based on a number of calculated descriptors. Five descriptors were used clogP, calculated molar refractivity (CMR), partial negative surface area, and the VolSurf W2 (polarizability) and D3 (hydrophobicity) descriptors. A model of acceptable quality was obtained (f = 0.94, SSE = 0.82) and tested on a 13 compound holdout set (r2 = 0.56, SSE = 0.98). An HQSAR model was then created that made use of 2D fragment fingerprints (threshold hERG IC50 = lpM). The best HQSAR model was validated on a holdout set of 13 compounds (f = 0.81, SSE = 0.67). 

Fractional total charge weighted partial positive surface area Fractional atomic charge weighted partial positive surface area Fractional partial negative surface area... 

Delgado reports a QSPR model [49] for the prediction of log(l/S) for a set of 50 chlorinated hydrocarbons including chlorinated benzenes, dibenzo-p-dioxins and PCBs. The model involves only two molecular descriptors, one geometry-dependent descriptor and one charged partial surface area (CPSA) descriptor. The geometric descriptor is the area of the shadow of the molecule projected on a plane defined by the X and Y axes XY shadow) the CPSA descriptor is the surface weighted atomic partial negative surface area (WNSA-3). The model has a squared correlation coefficient of 0.97 and standard deviation of 0.45 log units. 

---