SYNTHESES, SPECTROSCOPICAL PROPERTIES, AN D CRYSTAL-STRUCTURES OF BINUCLEAR HOMOLEPTIC AND HETEROLEPTIC MU-CARBIDO COMPLEXES OF IRON(IV) WITH PHTHALOCYANINATE AND TETRAPHENYLPORPHYRINATE LIGANDS

mu-Carbidophthalocyaninato (2-)iron(IV)tetraphenylporphyrinato(2-)iron (IV) (2) and u-carbido-bis(tetraphenylporphyrinato(2-)iron(IV)) (1) ar e synthesized by the reaction of phthalocyaninato(2-)ferrate(I) with d ichlorcarbenetetraphenylporphyrinato(2-)iron(II). 1 and 2 as well as m u-carbido-bis(phthalocyaninato (2-)iron(IV)) (3) are soluble in tetrah ydrofuran, but only 2 and 3 form solvent adducts 2a and 3a by coordina tion of thf to each of the iron atoms in trans position to the bridgin g C atom. The crystal structures of the solvates 1 . thf, 2a . thf and 3a . thf, crystallizing from the thf solutions, are determined: 1 . t hf, orthorhombic, Fddd, a = 21.966(3) Angstrom, b = 22.300(1) Angstrom , c = 31.220(3) Angstrom, Z = 8; 2a . thf, orthorhombic, P22(1)2(1), a = 14.487(3) Angstrom, b = 20.753(5) Angstrom, c = 25.803(7) Angstrom, Z = 4; 3a . thf, orthorhombic, P2(1)2(1)2(1), a = 12.642(1) Angstrom, b = 22.361(7) Angstrom, c = 23.629(3) Angstrom, Z = 4. In all three d ouble-decker complexes both ''tetrapyrrol'' ligands are held together by a linear Fe-C-Fe bridge in a staggered (1 . thf, 3a . thf) or eclip tic conformation (2a . thf). The Fe-C distances vary between 1.71 and 1.64 Angstrom (average: 1.68 Angstrom). In 2a . thf and 3a . thf the i ron atoms are nearly in the centre (Ct) of the (Np)4 planes (d(Fe-Ct) similar to 0.1 Angstrom), but in 1 . thf these atoms are directed by 0 .27 Angstrom towards the bridging C atom. The macrocyclic ligands of 1 . thf are severely concavely, those of 2a . thf and 3a . thf slightly distorted. The electronic absorption spectra and vibrational spectra are discussed.