Table 2.

Selected Properties of NO Adducts of Nonheme O,N-Ligated Diiron Sites in Proteins

protein	J ( cm−1)a	solvent bridgeb	δ (mm/s)	ΔEq (mm/s)d	ref
Fe2+{FeNO}7
FDPNO	17(2)	OH−	1.15, 0.68	+2.05, −1.56	e
deoxyHrNO	28	OH−	1.25, 0.72c	+2.66, + 0.61	34
[{FeNO}7]2
FDPdiNO	60(10)	OH−	0.71	1.85	e
RNRdiNO	5	H2O or none	0.75	−2.13, −1.73	18
MMOdiNO	>0	?	0.72	1.55	19

^aH_ex= J S₁∙S₂.

^bFe_p—Fe_D bridging ligand. Additional carboxylate bridging ligands are not listed.

^cδ4_K = δ_100K + 0.04 mm/s.

^dδ and ΔEQ values reported at 4.2 K. Signs of ΔE_q are omitted if not determined.

^eThis work.