The reaction of bis(triethylaluminum), A12(C2H5)6, with a variety of tetradentate Schiff-base ligands in benzene/acetonitrile solution yields ethane and the monoethylaluminum Schiff-base complexes. The ligands used include the 2:1 condensation products of salicylaldehyde with ethylenediamine, o-phenylenediamine, and propylenediamine (SALEN, SALOPHEN, and SALPN, respectively) and of acetylacetone with ethylenediamine (ACEN). These complexes are stable in the solid state in the absence of moisture but react with moisture and anhydrous HC1 in solution to yield ethane and the corresponding hydroxoaluminum and chloroaluminum complexes, respectively. The susceptibility of these complexes to moisture in solution is dependent to a remarkable degree on the flexibility of the ligand. It is proposed that the remarkable resistance to hydrolysis, as compared with nonchelated aluminum alkyl species, is related to the high energy state of the square-planar four-coordinate Al3+ species remaining on loss of the alkyl group. The X-ray crystal structure of C18H19N202A1 (A1(SALEN)C2H5, orthorhombic, P2¡2l2u a = 6.930 (3) Á, b = 10.186 (4) A, c = 23.092 (8) Á, Z = 4) reveals a 5-coordinate, square-pyramidal aluminum complex with an Al-C bond distance of 1.966 (7) Á. The average Al-O distance, 1.815 (15) Á, is much shorter than the Al-N distance, 2.020 (7) A. The aluminum is displaced 0.540 A from the least-squares plane of the ligating nitrogen and oxygen atoms, toward the ethyl group.The SALEN moiety adopts the usual "inverted umbrella" structure observed for monomeric transition-metal species.

Single-crystal X-ray work has been carried out on crystals containing the 1 -methylimidazole adduct of p-0x0-bis [ ( pht ha locya ni nato) iron (I I I)], [{ Fe ( pc) (mi m)}20] [ Fe ( pc) (mi m) 2] 03 Me,CO. The crysta Is are monoclinic, space group C2/c, with a = 35.236(5), b = 14.173(2), c = 23.220(3) A, p = 103.56(10)O and Z = 4. The structure was solved and refined using all data including zero intensities (5739). Only the atoms of the p-0x0 dimer were refined anisotropically beGause of data limitations. The Fe atoms in [{Fe(pc)(mim)},O] are nominally centred in the phthalocyanine plane, with an average Fe-N(pc) of 1.92(3) A and six-co-ordinate, with Fe-0 1.749(1) A and Fe-N(mim) 2.039(7) A. The Fe-0-Fe angle is 175.1 O. X-Ray data for [Fe(pc)(mim),] are as expected for six-co-ordinate lowspin nitrogen-containing base adducts of [Fe(pc)]. The crystal data are discussed in the light of similar results on [{Fe(pc) (mim)},C] and related compounds.

The structure of W(TPP)(0)(02) (TPP = tetraphenylporphyrinato) has been shown to have a cis arrangement of 0x0 and peroxo groups which are eclipsed with respect to the porphyrin nitrogen atoms.

The properties and crystal structure of [Mo(TPP)I2, obtained from the reaction of Mo(CO)6 and H2TPP (tetraphenylporphyrin), are discussed.

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