Computed bond lengths (in Å) and dihedral angle (in °) for M(S₂TTP)Cl₂ at the B3LYP/DEF2-TZVP level (M = Mn, Fe, Ni, Cu and Ru).

M	Parameter	Experimental	DFT
Ru19	2S + 1	—	1	3	5
	Ru–N	2.082	2.082	2.085	2.113
	Ru–S	2.251	2.247	2.280	2.296
	Ru–Cl	2.399	2.458	2.396	2.394
	ΔE (kcal mol−1)	—	0 3.5	38.5
	Dihedral angle of thiophen ring	12.7	12.4	14.5	10.0
Mn	2S + 1	—	4	6
	Mn–N	—	2.037	2.147
	Mn–S	—	2.454	2.386
	Mn–Cl	—	2.364	2.591
	ΔE (kcal mol−1)	—	16.1	0
	Dihedral angle of thiophen ring	—	11.7	12.6
Fe	2S + 1	—	1	3	5
	Fe–N	—	2.061	2.081	2.143
	Fe–S	—	2.181	2.184	2.335
	Fe–Cl	—	2.407	2.656	2.506
	ΔE (kcal mol−1)	—	9.6	11.8	0
	Dihedral angle of thiophen ring	—	12.1	12.3	11.3
Ni	2S + 1	—	1	3
	Ni–N	—	2.002	2.114
	Ni–S	—	2.362	2.322
	Ni–Cl	—	2.321	2.552
	ΔE (kcal mol−1)	—	22.2	0
	Dihedral angle of thiophen ring	—	11.2	11.9
Cu	2S + 1	—	2
	Cu–N	—	2.059
	Cu–S	—	2.360
	Cu–Cl	—	2.560
	ΔE (kcal mol−1)	—	—
	Dihedral angle of thiophen ring	—	11.8