6533b859fe1ef96bd12b75b7

RESEARCH PRODUCT

Synthesis, properties and X-ray crystal structure of schiff base organoimido complexes of rhenium(V)

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Abstract Re(NR)Cl 3 (PPh 3 )( 2 (R = p-CH 3 C 6 H 4 , CH 3 ) react with polydentate ligands (LH = N-methyl-, N-phenyl-, N-tolyl-salicylideneimine, half, N,N′-ethylenebis-, half N,N′-propylenebis-(salicylideneimine), 8-hydroxyquinoline and LH 2 = N-2-hydroxyphenylsalicylideneimine) to yield complexes of the type Re(NR)Cl 2- (L)PPh 3 . With 8-hydroxyquinoline the bisubstituted Re(NR)Cl(L) 2 complexes are also obtained. The compounds were characterized by elemental analysis, molecular weight, and i.r. spectra. The crystal and molecular structures of two arylimido complexes, Re(p-CH 3 C 6 H 4 N)Cl 2 )RNCHC 6 H 4 O)PPh 3 with R = C 6 H 5 or CH 3 , were determined from X-ray crystallography based on diffractometer data. The phenyl compound crystallizes in space group P2 1 /c of the monoclinic system, with a = 15.340(5) A, b = 21.115(6) A, c = 10.605(5) A, β = 91.36(5)°, and D x = 1.59 g cm −3 for four formula units in the cell. The structure has been refined by least-squares to the final R factor of 4.7% for the 3931 reflexions above background. The methyl compound crystallizes in space group P 1 of the triclinic system, with a = 13.457(5) A, b = 11.795(5) A, c = 10.997(5) A, α = 112.16(5)°, β = 108.17(5)°, γ = 86.36(5)°, and D x = 1.64 g cm −3 for two formula units in the cell. The structure has been refined by least-squares to the final R factor of 8.0% for the 4891 reflexions above background. The overall molecular structure is the same for both complexes. The Re atom is in a distorted octahedral configuration with two Cl atoms trans to one another, the arylimido group (bonded to Re via the N atom) trans to the O atom of the bidentate ligand, and the PPh 3 group trans to the N atom of the bidentate ligand. Bond distances and angles in the two molecules agree well. Mean values for some bond distances involving rhenium are: ReCl 2.418 A; ReP 2.44 A; ReO 1.98 A; ReN(arylimido) 1.73 A; ReN 2.14 A.