Table 5.

Selected EXAFS fitting results for 2•O₂PPh₂, 2•O₂AsMe₂, and 3•O₂PPh₂.^a

		Fe-O/N			Fe-O/N			Fe-O/N			Fe⋯C			Fe⋯X
Complex	Fit	N	R (Å)	σ2	N	R (Å)	σ2	N	R (Å)	σ2	N	R (Å)	σ2	N	R (Å)	σ2	Fc	F'd
2•O2PPh2	A	4	1.99	6.14	1	2.29	3.31				5	2.94	10.66	1P	3.12	−0.30	31	93
	B	4	2.00	6.54	1	2.31	3.64				5	2.99	2.19	5C	2.21	2.26	57	314
	C	4	2.00	6.69	1	2.31	2.71	1	2.54	0.58	5	2.99	3.55	1Fe	3.28	3.18	20	48
	D	4	2.00	6.57	1	2.30	1.50	1	2.51	3.00b	5	2.96	7.95	1Fe	3.25	4.06	12	20
														1P	3.14	3.00b
2•O2AsMe2	A	5	1.97	10.82	1	2.25	2.19				3	2.93	3.86	1Fe	3.25	0.98	41	179
	B	5	1.97	10.95	1	2.26	2.85				3	2.90	7.46	1As	3.19	1.94	39	161
	C	5	1.97	10.66	1	2.25	1.03				3	2.95	1.63	6C	3.28	0.40	72	628
	D	3	1.97	3.94	2	2.17	4.28	1	2.35	5.35	3	2.94	2.76	1Fe	3.27	1.24	16	31
	E	3	1.97	3.87	2	2.17	3.82	1	2.36	3.80	3	2.93	5.20	1As	3.21	2.24	15	31
	F	3	1.97	3.85	2	2.17	3.89	1	2.35	4.24	3	2.92	3.34	1Fe	3.13	19.43	13	32
														1As	3.21	1.97
	G	3	1.97	3.84	2	2.17	3.90	1	2.36	4.71	3	2.94	2.22	1Fe	3.27	1.02	13	32
														1As	3.45	12.71
3•O2PPh2	A	4	2.04	2.04	1	2.33	0.48	1	1.88	1.23	4	2.95	2.39	1Fe	3.47	4.59	17	25
	B	4	2.04	2.04	1	2.33	0.52	1	1.88	1.28	4	2.95	2.30	1P	3.61	1.50	26	58
	C	4	2.03	2.03	1	2.33	0.67	1	1.88	1.24	4	2.95	2.63	5C	3.50	2.99	31	83
	D	4	2.04	2.04	1	2.33	0.80	1	1.88	1.12	4	2.95	2.43	1Fe	3.44	3.73	14	20
														0.5P	3.39	0.69

^aResolution ~ 0.12 Å for 2•O₂PPh₂ and 3•O₂PPh₂ and ~ 0.14 Å for 2•O₂AsMe₂; σ² = Debye-Waller factor in units of 10⁻³ Ų.

^bσ² value held fixed during optimization.

^cF = goodness of fit calculated as $F=\sqrt{{{\displaystyle \sum k^6({\chi }_{\mathit{\text{exp}}}-{\chi }_{\mathit{\text{cal}}})}}^2/N}$ , where N = the number of data points. ³⁹

^dF' = F²/ν, where ν = n_idp − n_var, n_idp is the number of independent points in each data set and n_var is the number of variables used in each optimization step. F' is used to indicate the improvement of fit upon the introduction of a shell. ³⁹