QSPR with TAU indices: Boiling points of sulfides and thiols
Kunal Roy, Achintya Saha · INDIAN JOURNAL OF CHEMISTRY- SECTION A · 2004
The present pape r a ll empts to correlate th e boi ling points (BP) of 26 thi o ls and 45 sulfides with diffe rent, Topochemica ll y Arri ved Unique (TAU) indi ces (T, TR, F, B, Nv, Np, N Nx, Ny) i.n ord er to ex pl ore the utilit y o f th e TAU indices in modelin g studies. Statisti cal quality of th e re lations has been judged by the parame ters such as predic ted variance (Q explained va ri ance (Rr/), corre lati o n coe ffici e nt (R), variance rati o (F), etc. The stud y shows that th e TAU indices can explain up to 99.7% and predic t up \0 99.6% o f th e variance of boi lin g points o f th e combined data set. Mo reover. th e TAU indices can decode s pecifi c contributi o ns o f mo lecular bulk (s ize), functi onality, branching and shape paramete rs to th e boiling point s o f thi o ls a nd sulfides. In general. th e bo ilin g point increases with inc rease in bulk and decreases w ith in c rease in branching. Further th e thi o l functiona lity contributes more to th e bo iling point th an th e sulfide functionality. Topological descriptors are formulated in graph theoretic app roach 1.2 considering th e arrangements of atoms in th e (usuall y hydrogen- suppressed) molecular graph, neglecti ng three di mensional interatomic di stances, but taki ng into account branching and cyclicity 3-8. Various types of matrices ha ve been used for the numeri c description of chemical structures , e.g., adjacency matrix 5 , distance matrix 5 , reciprocal di stance matrix 9 , res ista nce distance matrix 1 0, distance h . II I' I