Table 1. Mössbauer Parameters of In Situ-Formed Iron Species Compared to Previously Reported Iron–Bisphosphine Intermediates^a.

species	geometry	isomer shift δ (mm/s)	quadrupole splitting |ΔEQ| (mm/s)
Fe(BenzP*)Br2 this work	dist. Td	0.77	3.00
Fe(SciOPP)Br228	dist. Td	0.94	2.80
Fe(dcype)Br230	dist. Td	0.72	3.21
Fe(BenzP*)BrPh this work	dist. Td	0.52	2.45
Fe(SciOPP)BrPh28	dist. Td	0.51	2.35
Fe(SciOPP)BrMes29	dist. Td	0.52	1.97
Fe(dcype)Br(3-MeOC6H4)30	dist. Td	0.51	2.49
Fe(BenzP*)Ph2 this work	dist. Td	0.33	1.65
Fe(SciOPP)Ph228	dist. Td	0.32	1.50
Fe(SciOPP)(Mes)229	sq. planar	0.28	3.67
Fe(dcype)(3-MeOC6H4)230	sq. planar	0.23	4.35
Fe(BenzP*)(THF)Ph2 this work		0.35	2.85
Fe(SciOPP)(THF)Ph228		0.33	3.13

^adcype = 1,2-bis(dicyclohexylphosphino)ethane. SciOPP = 1,2-(bis[3,5-di(tert-butyl)phenyl]phosphino)benzene.