Table 2 Calculated cocrystal formation energies (ΔEf,calc), halogen bond energies (EXB,calc), distances (dXB,calc) and ESP minima on the pnictogen atom or the phenyl ring for (tftib)(PPh3), (tftib)(AsPh3), (tftib)(SbPh3), (tftib)(BiPh3)a, and (tftib)(NPh3)b in cocrystal and gas phase

From: Halogen-bonded cocrystallization with phosphorus, arsenic and antimony acceptors

acceptor ΔEf,calc (kJ mol−1) EXB,calc (crystal, kJ mol−1) EXB,calc (gas, kJ mol−1) dXB,calc (crystal, Å) dXB,calc (gas, Å) ESP (pnictogen, kJ mol−1) ESP (phenyl, kJ mol−1)
NPh 3 b b 13.87 b 3.149 −28.9c −64.6
PPh 3 −15.40 16.96 22.79 3.363 3.318 −118.4 −62.0
AsPh 3 −11.38 13.12 15.66 3.529 3.514 −95.8 −63.5
SbPh 3 −7.36 12.88 15.67 3.577 3.589 −89.8 −61.4
BiPh 3 a +1.27 5.65 7.23 3.803 3.817 −6.0 −66.4
  1. aPutative structure for (tftib)(BiPh3) cocrystal was generated from that of (tftib)(SbPh3) by replacing the Sb atom with Bi and optimization
  2. bDifferent geometry of NPh3 compared to its congeners prevented generating a structure for the putative (tftib)(NPh3) cocrystal
  3. cValue corresponds to the point in the center of the molecule closest to the N atom