A series of porphyrins strapped and capped by benzene and amidobenzene rings have been prepared. O-2 and CO bindings to their iron(II) complexes have been examined, and the role of hydrogen-bonding in stabilizing O-2 binding has been measured. Each comparison between the benzene ring (no H-bonding) and the amidobenzene ring analogues showed a free energy gain of similar to 1 kcal/mol (at -45 degrees C) 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) Angstrom, b = 31.290(5) Angstrom, c = 11.221(3) Angstrom, beta = 104.62(2)degrees, Z = 4, and space group P2(1)/n. The structure was solved by the Patterson method and was refined by full-matrix least-squares procedures to R = 0.040 (R(w) = 0.041) for 3844 reflections with I greater than or equal to 3 sigma(F-2).