Table 1.

Optimization of reaction conditions^a.

Entry	Change in standard reaction conditions	Yield (1, %)b
1	NiCl2.glyme (5 mol%), 4,4'-dtbbpy (6 mol%)	36
2	None	54
3	Ni(cod)2 (5 mol%), 4,4'-dOMe-bpy (5.5 mol%)	77
4	Ni(cod)2 (10 mol%), 4,4'-dOMe-bpy (11 mol%)	75
5	H2O (10 equiv.) as additive	73
6	1 mol% Ir[dF(CF3)ppy]2(dtbbpy)PF6, Ni(cod)2 (5 mol%)	74
7	Ir[ppy]2(dtbbpy)PF6 instead of PS1	0
8	Ru(bpz)3·2PF6 instead of PS1	0
9	(9-MesAcr)ClO4 instead of PS1	0
10	4-CzIPN (2 mol%) instead of PS1, Ni(cod)2 (5 mol%)	30
11	without [Ir] photosensitizer	0
12	without [Ni] catalyst	0
13	without Light source	0
14	without base	trace
15	without fan cooling (around 50 °C)	51
16	(3-chloropropyl)benzene instead of alkyl bromide	0

^aStandard conditions: Alkyl bromide (0.1 mmol), THF (0.05 M, 2 mL), NiCl₂.glyme (5 mol%), 4,4'-dOMe-bpy (4,4'-dimethoxy-2,2′-bipyridyl) (5.5 mol%), Ir[dF(CF₃)ppy]₂(dtbbpy)PF₆ (2 mol%), K₂CO₃ (2 equiv.), 34 W blue LEDs, Ar, 48 h, room temperature.

^bYield determined by GC. Emission maximum of the light source used is 425 nm.