Isomerization energies and surface electrostatic potential analyses on nitriles and isocyanides

Abstract

Isocyanide-nitrile rearrangement has long been a continuing and interesting topic. A series of nitriles and isocyanides with the substituents of R=-

Stability, atomic charges, bond‐order analysis, and the directionality of lone‐electron pairs on nitriles and isocyanides

“…The optimized bond lengths of CH and CN in HCN: and NH and :CN in :CNH are 1.064 and 1.154 Å and 0.995 and 1.169 Å, respectively, also according well with the reported B3LYP‐D3(BJ)/def2‐QZVP results. [ 18 ]…”

“…Structural optimization on the selected nitriles RCN: and isocyanides :CNR ( R = AlH 2 , BeH, BH 2 , CCH, CF 3 , CH 3 , Cl, CN:, COOH, F, H, Li, MgH, Na, NH 2 , NO 2 , OH, PH 2 , SH, SiH 3 , and CHCH 2 ) in gas phase was performed at B3LYP‐D3(BJ)/def2‐QZVP level with Gaussian 09 D.01 package [ 21 ] according to our previous work. [ 18,22 ] The universal functional of B3LYP with D3 dispersion has been proved to be a reliable and highly efficient method for varied systems, even with small basis sets. [ 23–26 ] To obtain more accurate stabilization energies between the nitriles and isocyanides, single‐point energy (SPE) calculations were carried out at B2PLYP‐D3(BJ)/cc‐pVTZ level based on the optimized geometrical structures at B3LYP‐D3(BJ)/def2‐QZVP level.…”

“…The single-point isomerization free energies ΔG from R C N: to :C N R of these 21 isomer pairs at B2PLYP-D3(BJ)/cc-pVTZ level are shown in Figures 1 and 2, where a negative ΔG value denotes that R C N: is more unstable than the corresponding :C N R. The optimized bond lengths of C H and C N in H C N: and N H and :C N in :C N H are 1.064 and 1.154 Å and 0.995 and 1.169 Å, respectively, also according well with the reported B3LYP-D3 (BJ)/def2-QZVP results. [18] Calculating BDE is a straightforward and efficient method to estimate bond strength. [41][42][43] The BDE values between the substituents R and cyan/isocyan in gas phase can be measured by the enthalpic differences ΔH of R C N:/:C N R !…”

“…Recently, we have reported the molecular structures and isomerization energies for a series of RCN: and :CNR with 21 functional groups, and the substituent effect and bonding characters were discussed by surface electrostatic potential (ESP) colored van der Waals surfaces. [ 18 ] For these nitriles and isocyanides, the surface ESP analyses showed that the carbon atoms in :CN and the nitrogen atoms in CN: are always the global negative electrostatic extrema in whole molecules. The lone pair on the terminal atom of :CN or CN: may play a significant role in charge distribution, molecular electron density, and surface ESP.…”

Ab initio molecular dynamics simulations on the adsorption of 1-hydroxyethane-1,1-diphosphonic acid on the iron (100) surface

“…IRI method [51][52][53] can be used to graphically investigate chemical bonds and weak interactions. The definition of the IRI function is as follows: where a is an adjustable parameter, and a = 1.1 is adopted for standard definition of IRI.…”