Interaction of Derivatized Capped Iron(II) Porphyrin Complexes
Tang, H. and David Dolphin
A series of porphyrins strapped and capped by benzene and amidobenzene rings have been prepared. O2 and CO bindings to their iron(II) complexes have been examined, and the role of hydrogen-bonding in stabilizing O2 binding has been measured. Each comparison between the benzene ring (no H-bonding) and the amidobenzene ring analogues showed a free energy gain of ~1 kcal/mol (at -45 oC) for the amidobenzene derivatives. An X-ray structure analysis was carried out for the ferric (Cl-) complex of the benzene-capped porphyrin strapped by two butyl side chains. The crystals were monoclinic, with a = 10.557(3) Å, b = 31.290(5) Å, c = 11.221(3) Å, β= 104.62(2)o, Z = 4, and space group P21/n. The structure was solved by the Patterson method and was refined by full-matrix least-squares procedures to R = 0.040 (Rw = 0.041) for 3844 reflections with I ?3σ (F2).