Five crystal structures of which two involved Schiffbase derivatives and three involved "picket fence" porphyrin derivatives were determined.

1. α,α'-{2-(2'-pyridyl)ethyl}ethylenebis(salicylideniminato)-iron(II),Fe(salen-C₂H₄-py). Crystal and refinement data:- monoclinic,P2₁/c,a = 10.572(2), b = 11.465(2), c = 16.640(3) Å, β = 90.52(1)°; R = 0.056 for 1118 reflections having I>3σI; Z = 4. This high-spin complex has distorted trigonal-bipyramidal geometry with the following bond distances. :- r(Fe-N salen) average 2.093(7) Å, r(Fe-O salen) average 1.959(6) Å, r(Fe-Npy) 2.147(8) Å. Its stereochemistry is generally similar to the cobalt analogue, which forms an isolable dioxygen adduct.
2. The dioxygen adduct of Co(salen-C₂H₄-P.Y), [Co (salen- C₂H₄-py) (O₂]. CH₃CN. Crystal and refinement data:- monoclinic, P2₁/c, a= 9.562(2), b = 19.490(4), c = 12.770(3) Å, β = 106.01(2)°; Z = 4; R = 0.128 for 915 reflections having I>σI. This low-spin (S=½) complex has approximately octahedral symmetry with bond distances:- r(Co-N salen) average 1.88(2) Å, r(Co-) salen) average 1.89. (2) Å, r(Co-Npy) 2.03(2) Å and r(Co-OO₂( 1.84(3) Å. Dioxygen is angularly coordinated [diagram here] and the salen component is approximately planar. The results, and others, are interpreted in favour of a CoIII- O₂-species. This complex is a model for cobalt-substituted haemoglobin.
3. The dioxygen adduct of (1-methylimidazole)meso-tetra- (α,α,α,α-orthopivalamidephenylporphinatoiron(II), [Fe(TpivPP)-(1-Me-imid)(O₂)].½(C₆H₆).½(C₄N₂H₆). Crystal and refinement data:- monoclinic C2/c, a= 18.690(3), b = 19.514(3), c = 18.638(3) Å, β = 91.00(1)° ; Z = 4; R = 0.109 for 1784 reflections having I>σI. This essentially diamagnetic complex is approximately octahedral with bond distances:- r(Fe-Nporp)av. 1.98(1) Å, r(Fe-Nimid) 2.07(2) Å and r(Fe-OO₂) 1.75(2) Å. Dioxygen is angularly coordinated [diagram here] and there is an apparent trans effect in the axial connection. The validity of this complex as a model for the haem component of oxymyoglobin is assessed.
4. The dioxygen adduct of [FeII (TpivPP) (THT)]. (THT)₂, [Fe (TpivPP) (THT) (O₂)]. (THT)₂. Crystal and refinement data:- monoclinic P2₁/c, a= 16.951(3), b = 18.153(4), c = 25.470(4) Å, β = 107.14(8)°; Z = 4; R = 0.166 for 1521 reflections having I>σI. This complex is approximately octahedral, and the average r(Fe-Nporph) is 2.00 Å and r(Fe-S) is 2.49(2) Å. Dioxygen is angularly coordinated [diagram here] but definition is very poor. This complex is a possible model for the oxygenated intermediate in the catalytic cycle of cytochrome P450 camphor hydroxylase.
5. Catena-{μ-[(TpivPP) -N,N' ,N" ,N" I :O] -aquoiron(II). THT, polymeric-[Fe(TpivPP) (OH ₂)]. THT. Crystal and refinement data:- orthorhombic, P2₁2₁2₁, a= 15.448(4), b = 26.415(6), c = 14.960(4) Å; Z = 4; R = 0.116 for 2576 reflections having I>σI. In this high-spin complex a pivalamide oxygen atom of one "picket" is coordinated to the iron atom of another Fe(TpivPP) Å unit at a separation of 2.22(1) Å, thereby creating an infinite chain. A water molecule is semicoordinated to the iron atom on the hindered side of the porphyrin at a separation of 2.90(2) Å. The iron atom is displaced 0.28 Å from the least-squares plane of the porphinato nitrogen atoms towards the coordinated pivalamide oxygen atom. The average Fe-Nporph separation is 2.07(1) Å. The complex has stereochemical features in common with other high-spin metalloporphyrins.