. 2021 Feb 11;26(4):950. doi: 10.3390/molecules26040950

Table 1.

Summary of geometry, calculated bond distances ( $R_{c a l c}$ ), experimental bond distances ( $R_{e x p}$ ), calculated bond dissociation enthalpies (BDH $_{c a l c}$ ), experimental calculated bond dissociation enthalpies (BDH $_{e x p}$ ), vibrational spectroscopy data, electron densities ( $ρ_{b}$ ), and energy densities ( $H_{b}$ ) of targeted CC bonds for molecules 1–53 $^{a}$ .

#	sym	bond	$R_{c a l c}$	$R_{e x p}$	BDH $_{c a l c}$	BDH $_{e x p}$	$k^{a}$	$ω^{a}$	BSO n	$ρ_{b}$	$H_{b}$
1	D_3d	C−C	1.523	1.536 [97]	89.0	89.7 [98]	4.216	1092	1.000	1.659	−1.431
2	C_2v	C−C	1.524	1.528 [99]	87.4	87.2 [98]	4.160	1085	0.989	1.671	−1.443
3	C_3v	C−C	1.526	1.535 [100]	86.7	88.9 [98]	4.092	1076	0.976	1.675	−1.442
4	T	C−C	1.530	1.539 [26]	87.5	86.0 [98]	3.997	1063	0.958	1.669	−1.423
5	C_2h	C−C	1.541	1.544 [25]	82.8	86.6 [98]	3.786	1035	0.917	1.645	−1.369
6	D₃	C−C	1.577	1.582 [25]	80.4	76.0 [98]	3.229	956	0.807	1.544	−1.181
7	C₂	C−C	1.542	1.550 [101]	66.9	66.6 [98]	3.675	1020	0.895	1.601	−1.322
8	C₂	C−C	1.629	1.677 [18]	53.4	43.7 [102]	2.414	826	0.639	1.387	−1.925
9	C₁	C−C	1.597	1.601 [103]	73.1	60.2 [104]	2.888	904	0.737	1.481	−1.079
10	C₂	C−C	1.611	1.635 [103]	61.2	51.0 [104]	2.693	873	0.697	1.443	−1.016
11	C₂	C−C	1.631	1.635 [105]	52.2	44.7 [105]	2.290	805	0.611	1.371	−1.918
12	D₂	C−C	1.699	-	16.6	-	1.518	678	0.439	1.188	−1.663
13	S₆	C−C	1.669	1.670 [106]	33.9	-	1.919	737	0.526	1.275	−1.830
14	C_2h	C−C	1.523	1.539 [26]	86.0	87.2 [98]	4.177	1087	0.993	1.672	−1.447
15	C_3v	C−CN	1.472	1.460 [107]	119.2	115.8 [98]	4.432	1120	1.041	1.787	−1.852
		C−C	1.535	-	-	-	3.915	1052	0.942	1.644	−1.388
16	C₂	C−C	1.599	1.601 [103]	70.3	62.2 [106]	2.853	898	0.730	1.477	−1.070
17	C₂	C−C	1.622	1.630 [18]	50.0	44.0 [106]	2.509	842	0.658	1.410	−1.965
18	C₂	C−C	1.589	1.606 [103]	72.1	57.8 [106]	3.050	929	0.770	1.506	−1.119
19	C₁	C−C	1.614	1.660 [19]	78.6	-	2.792	889	0.717	1.427	−1.996
20	C₁	C−C	1.647	1.647 [18]	71.4	≈ 71 [18]	2.401	824	0.635	1.331	−1.855
21	C₁	C−C	1.656	1.659 [18]	64.3	-	2.245	797	0.602	1.310	−1.824
22	C₁	C−C	1.693	1.704 [18]	-	-	1.874	728	0.521	1.218	−1.694
23	C₁	C−C	1.787	-	-	-	1.142	568	0.351	1.014	−1.465
24	C₁	C−C	1.695	1.707 [18]	-	-	1.861	726	0.519	1.211	−1.687
25	D_2h	C−C	1.642	1.640 [108]	-	-	2.411	826	0.637	1.317	−1.857
26	C₁	C−C	1.708	1.754 [31]	-	-	1.788	711	0.502	1.153	−1.620
27	C_2h	C−C	1.651	-	-	-	1.591	671	0.456	1.347	−1.876
28	C_3v	C−C	1.512	1.516 [109]	86.9	88.3 [98]	4.154	1084	0.988	1.747	−1.615
29	D_3d	C−C	1.583	1.564 [110]	73.4	70.1 [98]	2.944	913	0.749	1.575	−1.181
30a	D_3d	C−C	1.935	-	41.2	-	0.894	503	0.286	0.523	−1.194
30b	C_2h	C−C	1.591	-	42.7	-	0.971	524	0.306	1.272	−1.929
31	C_2v	C−C	1.930	-	-	-	0.604	413	0.209	0.742	−1.242
32	C_s	C−C	1.495	1.501 [99]	100.0	100.9 [98]	4.575	1138	1.068	1.770	−1.637
		C=C	1.324	1.336 [99]	-	-	9.821	1667	1.997	2.444	−1.197
33	D_2h	C=C	1.322	1.339 [97]	173.9	172.2 [98]	9.961	1679	2.000	2.449	−1.214
34	C_2h	C−C	1.457	1.467 [111]	-	116.0 [98]	5.119	1203	1.169	1.920	−1.934
		C=C	1.329	1.349 [111]	-	-	9.537	1642	1.931	2.426	−1.145
35	C₁	C−C	1.497	1.502 [112]	98.2	99.6 [98]	4.484	1126	1.051	1.776	−1.639
		C=C	1.324	1.340 [112]	-	-	9.804	1665	1.975	2.443	−1.195
36	C_s	C−C	1.501	1.500 [113]	97.3	99.7 [98]	4.382	1113	1.032	1.775	−1.628
		C=C	1.324	1.341 [113]	-	-	9.811	1666	1.976	2.443	−1.198
37	C_s	C−C	1.520	1.522 [103]	96.1	97.5 [98]	4.179	1087	0.993	1.749	−1.573
		C=C	1.324	-	-	-	9.765	1662	1.968	2.438	−1.188
38	D_∞h	C≡C	1.194	1.208 [97]	228.1	229.9 [98]	17.777	2243	3.190	2.894	−1.700
39	C_3v	C−C	1.455	1.450 [26]	124.3	123.5 [98]	5.254	1219	1.194	1.844	−1.895
		C≡C	1.196	1.207 [26]	-	-	17.515	2226	3.153	2.862	−1.742
40	C_3v	C−C	1.455	1.458 [99]	122.9	121.1 [98]	5.141	1206	1.173	1.828	−1.931
41	C_s	C−C	1.425	1.431 [26]	135.3	133.6 [98]	5.777	1278	1.289	1.974	−1.151
		C=C	1.329	-	-	-	9.564	1645	1.936	2.418	−1.137
		C≡C	1.199	-	-	-	17.264	2210	3.116	2.860	−1.699
42	C_s	C−C	1.430	1.429 [114]	131.7	132.1 [98]	5.582	1256	1.254	1.938	−1.141
		C=C	1.327	1.339 [114]	-	-	9.645	1656	1.957	2.428	−1.166
43	D_∞h	C−C	1.372	1.383 [26]	158.3	155.0 [98]	7.406	1447	1.575	2.142	−1.517
		C≡C	1.199	1.209 [115]	-	-	17.160	2203	3.101	2.858	−1.684
44	C_∞v	C−C	1.375	1.379 [116]	150.9	152.4 [98]	7.348	1442	1.565	2.122	−1.491
		C≡C	1.196	1.204 [116]	-	-	17.470	2223	3.146	2.878	−1.708
45	C_s	C−C	1.504	1.512 [117]	103.4	103.9 [98]	4.528	1132	1.059	1.745	−1.581
46	C_s	C−C	1.506	1.524 [118]	101.8	102.3 [98]	4.446	1121	1.044	1.751	−1.585
47	C_s	C−C	1.514	1.500 [119]	125.0	102.1 [98]	4.274	1100	1.011	1.732	−1.540
48	C_s	C−C	1.530	1.524 [120]	99.4	97.4 [98]	3.966	1059	0.952	1.681	−1.439
49	C_s	C−C	1.486	1.520 [121]	-	111.9 [122]	4.751	1159	1.101	1.815	−1.708

50	C_s	C−C	1.471	1.475 [123]	-	116.9 [98]	4.919	1180	1.132	1.868	−1.820
		C=C	1.327	-	-	-	9.549	1644	1.933	2.427	−1.154
51	C_2v	C−C	1.430	1.436 [124]	-	140.7 [98]	5.750	1275	1.284	1.961	−1.112
		C≡C	1.198	-	-	-	17.286	2211	3.119	2.860	−1.707
52	C_2v	C−C	1.433	1.438 [124]	-	132.7 [98]	5.569	1255	1.252	1.929	−1.116
53	D₂	C−C	1.482	1.480 [125]	-	118.0 [98]	4.850	1171	1.120	1.840	−1.752

^a Calculated and experimentally determined CC bond distances R(CC) in Å. CC local stretching force constants (k^a) in mdyn/Å, local vibrational mode frequencies (ω^a) in cm⁻¹, and bond strength order represented by BSO n values. Calculated and experimentally determined bond dissociation enthalpies (BDH) in kcal/mol. More detailed information on the experimental values is provided in the Supporting Information, Tables S1 and S2. The electron density at the CC bond critical point r_b in e/Å³ and the energy density at the CC bond critical point H_b in Hartree/Å³. Calculated BDH values were computed with G4 and all other values were calculated with ωB97X-D/aug-cc-pVTZ. “-” no data available. The numbers within the table correspond to the molecules shown in Figure 1.