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Calculated Proton Affinity

20 10 26 10 44
Name Species   Species Name
Pyrrole C4H5N C4H6N+ pyrrole, beta-protonated

Bonding changes

Bond type C-N changed by -1
Bond type C=C changed by -1
Bond type C-C changed by +1
Bond type H-C changed by +1
Bond type C=N gained 1
Proton Affinities (kJ/mol)
Proton Affinities in kJ/mol
Methods with predefined basis sets
semi-empirical AM1  
PM3  
PM6  
composite G2 814
G3 815
G3B3 818
G4 818
CBS-Q 809

Proton Affinities in kJ/mol
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF 1069 882 882 875 894 898 880 886 888 902   883 887 886 882 883
density functional LSDA   843 843     840 819   820 838     825 816 813  
BLYP 1023 880 880 872 877 880 853 858 859 878   851 862 854 847 848
B1B95 1009 858 858 850 865 832 843 818 846 862   849 848 851 846 847
B3LYP 1022 874 874 867 874 877 637 858 858 876   852 861 854 849 850
B3LYPultrafine   874     874 877 854 858       852 861 854 849 850
B3PW91 1018 870 870 865 871 874 856 858 859 874   855 861 856 853 853
mPW1PW91 1019 873 869 864 874 877 859 861 858 873   854 864 856 852 852
M06-2X 1015 857 857 848 852 855 837 840 841 854   837 842 836 834 833
PBEPBE 1016 870 870 864 867 870 848 852 853 869   847 855 849 843 844
PBEPBEultrafine   870     867 870 848 852       847 855 849 843 844
PBE1PBE 1018 866 866 860 866 866 851 854 855 869   850 856 852 848 848
HSEh1PBE 1019 866 866 860 866 869 851 854 855 869   850 856 851 847 848
TPSSh 1021 875 875 871 878 880 862 865 866 880   861 867 863 859 858
wB97X-D 1026 874 874 869 876     862 863 879   860   862   859
B97D3 1028 888 888 883 887 890 869 873 873 889 864 868 875 870 864 865
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
Moller Plesset perturbation MP2 1082 874 874 860 851 863 620 835 843 848   625 844 830 824 821
MP2=FULL 1082 874 874 860 850 863 838 834 843 851   624 844 831 824 823
MP3         874   902         648 870      
MP3=FULL   889 889 875 873 886 864 860 869 878   648 870 637 854  
MP4   892                   648        
MP4=FULL         871                      
B2PLYP 1044 874 874 865 868 874 850 852 855 869   848 857   842 842
B2PLYP=FULL 1044 874 874 865 868 874 850 852 855 870   848 857 848 842 843
B2PLYP=FULLultrafine 1044 874 874 865   874 850 852 855 870   848     842  
Configuration interaction CID   889 889 877 879     868                
CISD   890 890 879 880     869                
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
Quadratic configuration interaction QCISD   900 900 887 882 894 872 869 878 884   658 879   863  
QCISD(T)                       655        
QCISD(T)=FULL             866                  
Coupled Cluster CCD   894 894 880 877 889 867 864 873 878   652 873 642 857  
CCSD         881         882   656 877   645  
CCSD=FULL         881         885   867 877 866 862  
CCSD(T)                       655        
CCSD(T)=FULL                       655        
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ

Proton Affinities in kJ/mol
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 872 892 870 888 863 863     884
density functional B3LYP 862 871 857 864 855 856     852
PBEPBE                 846
wB97X-D 868 878 863 871 861 861      
Moller Plesset perturbation MP2 854 848 636 837 844 844     826
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.