Optimized Au–Au distance, R_e, for models 1 and 2 at the different levels. Equilibrium distance R_e in pm; interaction energy V(R_e) in kJ mol⁻¹.

Monomer	Method	Au (basis)	R e	V(Re)
[AuCl(CNH)]2 (5)	HF	2f	402.8	−23.8
	MP2	2f	352.2	−42.3
	SCS-MP2	2f	362.7	−34.9
	CCSD(T)	2f	360.9	−34.8
	HF	3f2g	405.7	−23.9
	MP2	3f2g	346.7	−44.6
	SCS-MP2	3f2g	356.6	−37.2
	CCSD(T)	3f2g	360.7	−35.6
	PW91	3f2g	369.3	−23.3
	M06L	3f2g	352.3	−33.0
	PBE-D3	3f2g	352.6	−38.1
	B3LYP-D3	3f2g	350.8	−46.0
	PBEa	3f2g	352.6	−23.3
	B3LYPa	3f2g	350.8	−17.7
[AuCl(CNCH3)]2 (6)	HF	2f	391.9	−28.6
	MP2	2f	352.5	−47.3
	SCS-MP2	2f	358.8	−40.3
	CCSD(T)	2f	363.7	−40.6
	HF	3f2g	393.2	−28.0
	MP2	3f2g	346.0	−50.4
	SCS-MP2	3f2g	354.4	−42.5
	CCSD(T)	3f2g	359.8	−42.5
	PW91	3f2g	365.3	−28.8
	M06L	3f2g	347.9	−41.0
	PBE-D3	3f2g	347.8	−46.8
	B3LYP-D3	3f2g	346.9	−54.2
	PBEa	3f2g	347.8	−29.3
	B3LYPa	3f2g	346.9	−30.9

^aSingle point at R_e in D3.