NEW LITHIUM PORPHYRIN DERIVATIVES - SYNTHESIS OF LI-2(P)(ET(2)O)(2) (P=TTP, TBPP) AND SOLUTION STRUCTURE OF LI-2(TTP)(ET(2)O)(2) BY LI-7 AND N-15 NMR

The preparation of new lithium porphyrinates Li-2(P)(ether)(2) [P = dianion of tetra-p-tolylporphyrin (TTP), dianion of tetrakis(p-tert-butylphenyl)porphyrin (TBPP); ether = Et(2)O, Bu(2)O] is reported, employing a slight modification of the established literature procedure. The new derivatives are quite soluble in nonpolar solvents and possess a well-defined stoichiometry. Variable temperature H-1, Li-7, and N-15 NMR spectroscopy served to elucidate the solution structure of Li-2(TTP)(Et(2)O)(2). The two lithium atoms are coordinated symmetrically to the four porphyrin nitrogens above and below the porphyrin plane and each binds to an additional diethyl ether oxygen. Base-free dilithium porphyrins were also prepared. In addition an improved synthesis of 3,4-diethylpyrrole, the precursor for preparation of octaethylporphyrin (H(2)OEP), is reported.