Gaussian16 TS-optimization of TS5 (16->15)  at the 
 #temperature=278 freq opt=(TS,noeigentest,calcfc) empiricaldispersion=
 gd3 b3lyp/6-31+g(d,p) scrf=(Read,PCM,solvent=water)
level of theory. Epsilon adjusted to 144.8 to match that of HCN at 278 K.
100  is the most stable TS
