摘要
Various imido tungsten derivatives incorporating bidentate pyrrole-piperazine, pyrrole-morpholine, pyrrole-imine and keto-amine precursors were synthesized. Reacting W(=N t Bu) 2 (NH t Bu) 2 with one equivalent of the pyrrole-phenylpiperazine ligand {C 4 H 3 NH-[2-CH 2 N(CH 2 CH 2 ) 2 NPh]} in toluene generated [W(=N t Bu) 2 (NH t Bu){C 4 H 3 N-[2-CH 2 N(CH 2 CH 2 ) 2 NPh]}] (1). Similarly, addition of W(=N t Bu) 2 (NH t Bu) 2 to one equivalent of the pyrrole-morpholine ligand {C 4 H 3 NH-[2-CH 2 N(CH 2 CH 2 ) 2 O]} in toluene afforded [W(=N t Bu) 2 (NH t Bu){C 4 H 3 N-[2-CH 2 N(CH 2 CH 2 ) 2 O]}] (2), which was converted to [W(=N t Bu) 2 {C 4 H 3 N-[2-CH 2 N(CH 2 CH 2 ) 2 O]}] 2 (μ 2 -O) (3) in moisture. Reacting the pyrrole-imine ligand {C 4 H 3 NH-[2-CH=N(C 6 H 3 -2,6- i Pr 2 )]} with one equivalent of W(=N t Bu) 2 (NH t Bu) 2 in toluene gave [W(=N t Bu) 2 (NH t Bu){C 4 H 3 N-[2-CH=N(C 6 H 3 -2,6- i Pr 2 )]}] (4), which was transformed to [W(=N t Bu)(NH t Bu){C 4 H 3 N-[2-CH=N(C 6 H 3 -2,6- i Pr 2 )]}(μ-O)] 2 (5) upon absorbing moisture. Furthermore, when one equivalent of {C 4 H 3 NH-[2-CH=NC 2 H 4 N(C 2 H 4 ) 2 O]} reacted with W(=N t Bu) 2 (NH t Bu) 2 in toluene, {W(=N t Bu) 2 {C 4 H 3 N-[2-CH=NC 2 H 4 N(C 2 H 4 ) 2 O]} 2 } (6) was isolated. The tungsten keto-amine compounds {W(=N t Bu) 2 [OCMeCHCMeN(C 6 H 3 -2,6- i Pr 2 )] 2 } (7) and {W(=N t Bu) 2 [OCMeCHCMeNCH 2 CH 2 N(CH 2 CH 2 ) 2 O] 2 } (8) were obtained by the reaction between W(=N t Bu) 2 (NH t Bu) 2 and two equivalents of the corresponding keto-amine ligands in toluene. All the tungsten derivatives were characterized by 1 H and 13 C NMR spectroscopy. Single crystal X-ray diffraction analysis revealed that in compounds, 1, 3, 5, 6 and 7, the central W atom belonged to either a distorted trigonal bipyramidal or an octahedral geometrical arrangement. Overall, the influence of the substituted pyrrole and keto-amine bidentate precursors on the imido tungsten derivatives were explored and structurally constructed.