Formic acid dehydrogenation with [IrCl(CO)(PPh₃)₂], 3 and 4^a.

Entry	Catalyst	Additive	H2 (mmol)b	TON	TOF (h−1)c
1	Vaska	—	0.14	50	99
2	3	—	0.25	98	195
3	4	—	2.55	225	449
4	Vaska	NEt3	1.45	504	1008
5	3	NEt3	1.25	452	904
6	4	NEt3	0.61	222	443
7	Vaska	HCOONa	2.20	708	1416
8	3	HCOONa	12.35	4875	9750
9	4	HCOONa	0.96	390	779

^{a a}Conditions: neat formic acid (0.5 mL), catalyst (0.02 mol%), additive (5 mol%), 90 °C.

^bFrom monitoring gas evolution by a Man on the Moon millireactor (see ESI for details).

^cTOF measured after 30 min.