. 2015 Jun 22;54(13):6439–6461. doi: 10.1021/acs.inorgchem.5b00751

Table 2. Geometric Parameters for the Lowest-Energy Valence Isomers of Three Representative Protonation States when the [4Fe–4S] Cluster Is Both Oxidized⁵⁰ and Reduced by One Electron.

		RO^HP^–E^–(ROH)			RO^HP^HE^–(ROH)			RO^HP^HE^H(ROH)
	exp	ox	red	Δ^a	ox	red	Δ^a	ox	red	Δ^a
cluster bond lengths
Fe1–S5	2.344	2.218	2.227	0.01	2.215	2.272	0.06	2.209	2.251	0.04
Fe1–S6	2.393	2.301	2.313	0.01	2.298	2.290	–0.01	2.280	2.268	–0.01
Fe1–S7	2.364	2.328	2.338	0.01	2.317	2.319	0.00	2.313	2.325	0.01
Fe2–S5	2.217	2.323	2.304	–0.02	2.324	2.340	0.02	2.333	2.343	0.01
Fe2–S6	2.186	2.203	2.253	0.05	2.201	2.209	0.01	2.210	2.215	0.00
Fe2–S8	2.181	2.362	2.392	0.03	2.359	2.390	0.03	2.353	2.391	0.04
Fe3–S5	2.319	2.313	2.306	–0.01	2.317	2.333	0.02	2.305	2.333	0.03
Fe3–S7	2.281	2.236	2.299	0.06	2.237	2.255	0.02	2.238	2.255	0.02
Fe3–S8	2.306	2.357	2.358	0.00	2.350	2.372	0.02	2.360	2.382	0.02
Fe4–S6	2.308	2.314	2.325	0.01	2.319	2.308	–0.01	2.325	2.325	0.00
Fe4–S7	2.217	2.320	2.326	0.01	2.324	2.305	–0.02	2.326	2.310	–0.02
Fe4–S8	2.276	2.245	2.265	0.02	2.242	2.312	0.07	2.242	2.296	0.05
Fe2–S_C12	2.283	2.263	2.312	0.05	2.258	2.314	0.06	2.257	2.311	0.05
Fe3–S_C197	2.285	2.283	2.337	0.05	2.274	2.337	0.06	2.271	2.324	0.05
Fe4–S_C96	2.264	2.295	2.357	0.06	2.290	2.348	0.06	2.291	2.353	0.06
HMBPP bond lengths
Fe1–O_C4	2.046	2.108	2.161	0.05	2.133	2.148	0.01	2.254	2.282	0.03
Fe1–C₃	3.039	3.627	3.639	0.01	3.551	3.629	0.08	3.399	3.431	0.03
Fe1–C₂	2.913	3.267	3.306	0.04	3.266	3.310	0.04	3.220	3.241	0.02
HMBPP bond lengths
O_C4–O_T167	2.702	2.816	2.880	0.06	2.914	2.843	–0.07	3.179	3.161	–0.02
O_T167–O_E126	2.761	2.770	2.799	0.03	2.771	2.795	0.02	2.667	2.654	–0.01
O_E126–O_W1	2.578	3.133	3.131	0.00	2.907	3.051	0.14	3.711	3.740	0.03
O_W1–O_PPi	2.548	2.746	2.753	0.01	3.006	2.989	–0.02	2.836	2.841	0.01
O_C4–O_E126	3.526	4.337	4.473	0.14	4.358	4.472	0.11	4.200	4.155	–0.05
O_C4–O_PPi	4.782	4.958	4.970	0.01	4.890	4.944	0.05	4.874	4.861	–0.01
HMBPP angle
C₂–C₃–C₄–O_C4	2.046	–104.6	–103.7	0.9	–101.8	–103.7	–1.9	–99.1	–99.3	–0.2

The differences in bond length (Å) or angle (deg) between the oxidized and 1e^– reduced states are given under the column labeled Δ.

Table 2. Geometric Parameters for the Lowest-Energy Valence Isomers of Three Representative Protonation States when the [4Fe–4S] Cluster Is Both Oxidized50 and Reduced by One Electron.

Table 2. Geometric Parameters for the Lowest-Energy Valence Isomers of Three Representative Protonation States when the [4Fe–4S] Cluster Is Both Oxidized⁵⁰ and Reduced by One Electron.