3. Calculated Triplet Energies (eV) from Regular Scalar-Relativistic (SR) and Time-Dependent (TD) Scalar- (SR) and Spin-Orbit (SO) Relativistic B3LYP* Calculations.

	SR-B3LYP*	TD-SR-B3LYP*		TD-SO-B3LYP*
	E T1	E T1	E S1	Lowest excitation energy	f
Porphyrins
Re[Por](N)	0.83	0.55	0.58	0.56	3.18 × 10–8
Re[Por](O)(F)	1.25	1.19	1.45	1.19	2.93 × 10–7
Ir[Por](Me)	1.64	1.55	1.77	1.46	1.02 × 10–5
Pd[Por]	1.84	1.79	2.46	1.79	1.43 × 10–8
Pt[Por]	1.93	1.89	2.35	1.89	2.35 × 10–7
Corroles
Re[Cor](O)	1.58	1.54	2.06	1.54	6.90 × 10–8
Re[Cor](S)	0.98	0.98	1.38	0.99	5.69 × 10–7
Re[Cor](Se)	0.88	0.87	1.28	0.87	5.42 × 10–7
Ru[Cor](N)	1.50	1.46	1.82	1.46	3.63 × 10–7
Os[Cor](N)	1.56	1.52	2.28	1.52	1.60 × 10–9
Ir[Cor](py)2	1.51	1.47	2.10	1.47	1.64 × 10–6
Pt[Cor](Ph)(py)	1.51	1.47	2.25	1.47	1.90 × 10–8
Au[Cor]	1.57	1.52	2.42	1.52	1.46 × 10–8

^aThese triplet energies are adiabatic singlet–triplet gaps and were obtained from single point scalar-relativistic B3LYP* calculations on symmetry-unconstrained OLYP-D3 optimized geometries for M _S = 0 and 1.

^bBoth scalar-relativistic and spin–orbit time-dependent B3LYP* calculations were carried out on symmetry-unconstrained OLYP-D3 optimized geometries for M _S = 1. The lowest excitation energies thus correspond to phosphorescence from a geometry-relaxed triplet state.

^cThe spin–orbit relativistic oscillator strengths f are expected to be proportional to phosphorescence quantum yields.