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These macrocycles were synthesized from the hitherto unknown precursors methyl 3,4-dimethylfuran-2-carboxylate (11) and methyl 4-ethyl-3-methylfuran-2-carboxylate (12). Single-crystal X-ray diffraction structures of the bis(hydrochloric acid) salt (5a) and the bis(trifluoroacetic acid) salt (5b) of 5 and of the bis(hydrochloric acid) salt (6a) of 6 were obtained. These structures are compared to those of the parent all-aza sapphyrin 4. In this context, we report the first solid-state structural analysis of a trifluoroacetic acid salt of sapphyrin (4b). Crystals of 5a are triclinic, space group P1 h in a cell of the dimensions a ) 11.9686(13) Å, b ) 12.790(2) Å, c ) 16.236(2) Å, R ) 80.924(10)°, β ) 88.845(9)°, γ ) 80.481(10)°, V ) 2420.5(5) Å 3 , F(000) ) 1036, F ) 1.38 g cm 3 , with Z ) 2. Crystals of 5b are monoclinic, space group P2 1 /c, in a cell of the dimensions a ) 9.590(1) Å, b ) 33.911(3) Å, c ) 13.200(1) Å, β ) 94.931(6)°, V ) 4276.8(6) Å 3 , F(000) ) 1904, F ) 1.42 g cm 3 , with Z ) 4. Crystals of 6a are triclinic, space group P1 h, in a cell of the dimensions a ) 12.827(3) Å, b ) 13.116(3) Å, c ) 17.202(7) Å, R ) 82.89(2)°, β ) 82.14(2)°, γ ) 80.22(1)°, V ) 2810(2) Å 3 , F(000) ) 1184, F ) 1.36 g cm 3 , with Z ) 2. Crystals of 4b are triclinic, space group P1 h, in a cell of the dimensions a ) 11.431(3) Å, b ) 11.563(2) Å, c ) 16.367(4) Å, R ) 88.07(2)°, β ) 75.25(2)°, γ ) 86.50(2), V ) 2087.8(9) Å 3 , F( 000) ) 872, F ) 1.32, with Z ) 2. The monooxasapphyrin salt 5a displays a structure very similar to that of the parent all-azasapphyrin (4a) in that one chloride anion is bound 1.936 Å above and one chloride anion 1.814 Å below the plane of the macrocycle. These distances are 1.774 and 1.877 Å, respectively, for 4a. Almost the same behavior is found for 5b. Here, the carboxylate anions are bound 1.085 Å above and 1.870 Å below the plane of the macrocycle. These distances are 1.305 and 1.444 Å, respectively, for 4b. Completely different behavior is observed in the case of 6a. In this instance, only one chloride anion is bound directly with a distance of 1.685 Å above the plane of the macrocycle, while the other chloride anion is well removed from the dioxasapphyrin and solvated by four chloroform molecules.

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The synthesis, characterization and X-ray structure of the novel three dimensional tris(bipyrr0)methane 3 is reported; this species is predisposed to self-assemble into a cryptandlike dimer in both organic solution and the solid state.Compounds containing three pyrrole units bonded via the aposition to an sp3 hybridized carbon have been known for at least 80 years.] Dubbed tripyrrylmethanes (e.g. 1) Corwin and co-workers2 proposed these species as intermediates in the formation of dipyrromethenes after the initial work of Piloty, Krannich and Will. la They found that the condensation of an. afree pyrrole with a 2-formylpyrrole could give rise to several different dipyrromethanes, presumably through an intermediary tripyrrylmethane, which was never characterized beyond its elemental composition and melting point. The finding that the bacterial pigment prodigiosin,3 originally proposed as being a

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