Table 1.

Zwitterionic valine structures.

Entry	CSD symbol[a]	Chirality chain			Distances [Å]		Attraction CαN/C′O angles [°]		Comments
		Config. Cα	Ocis‐C′‐Cα‐N rotation angle ψ [°]	Otrans‐C′‐Cα‐Ocis pyramidal angle θ [°]	Ocis−N	Ocis−C(iPr)	N‐Cα‐C′(O)	(iPr)C‐Cα‐C′(O)
1	LVALIN01(1)	L	−17.48	−177.78	2.66	3.39	109.26	112.72	enantiomer(1)
4	VALIDL03	L	−23.31	−179.09	2.67	3.33	110.02	112.47	racemate[b]
8	LVALIN01(2)	L	−42.81	−177.66	2.76	3.10	109.33	110.48	enantiomer(2)
12	AHEJEC(1)[c]	D	17.95	177.75	2.66	3.38	109.31	112.98	enantiomer(1)
18	AHEJEC03(2)[c]	D	43.99	177.82	2.75	3.09	109.23	110.74	enantiomer(2)
20	OPEFUL[1]	L	−5.53	−181.00	2.60	3.51	107.19	116.10	+l‐valine⋅HCl adduct
25	GUQJUZ[1](2)	L	−20.39	−177.28	2.64	3.30	107.90	112.64	+valine⋅naphthalene‐ 1,5‐(SO3H)2 adduct
30	GOLVUY	L	−35.59	−177.34	2.69	3.17	108.04	110.44	+d‐n‐BuAA[d]
40	SONCED[c]	D	25.84	179.48	2.68	3.31	109.52	112.63	+l‐phenylalanine
	average		−27.74	−178.32	2.69	3.28	108.86	111.95

[a] Parenthesis () indicate independent molecules in the unit cell, whereas brackets [] differentiate between ⁺NH₃CH(ⁱPr)COO⁻ and ⁺NH₃CH(ⁱPr)COOH. [b] Racemates given as l‐compounds. [c] For average calculation rotation angle and distortion angle are inverted. [d] AA=amino acid.