Tantalum Complexes of Diphenyldipyrrolide Dianion:  Partial Hydrogenation of a Phenyl Ring

Abstract

The reactivity of the pentavalent dipyrrolide complex {[Ph2C(C4H3N)2]2TaCl2}{Li(THF)4}·2THF was investigated. While an isostructral dimethyl derivative was readily prepared by treatment with MeLi, reaction with NaHBEt3 gave a major reorganization, affording a mixture of [Ph2C(C4H3N)2]Ta[(1,4-η1:η1-2,3-η2-C6H7PhC(C4H3N)2][Na(OEt2)] and [Ph2C(C4H3N)2]3Ta[Na(OEt2)]2·(OEt2). The first complex arises from partial hydrogenation of one of the ligand phenyl rings performed by an intermediate Ta hydride. In the second case, ligand scrambling occurred along with reduction of the metal center.

Aluminum Compounds Containing η1‐ and/or η5‐Bidentate Dianionic Pyrrolyl–Methylamide Ligands

“…The terminal hydride was not observed in the 1 H NMR spectrum, presumably due to the quadrupole interaction with the aluminum nucleus (I = 5/2). [19] However, the solid-state IR spectrum supports the existence of a terminal AlÀH in 1 as evidenced by the absorption at ñ = 1912 cm [20] Again, the methylene protons of the CH 2 NtBu gave a pseudo-AB spin system showing two very close doublets at d = 3.99 and 4.03 ppm.…”

“…Although pyrrolyl ligands can coordinate to metals in a h 1 or h 5 fashion, only a few limited examples of pyrrolyl ligands bound to two metals with h 1 :h 5 modes have been structurally characterized. [20,22] The dihedral angle between the two AlN 2 C 2 five-membered rings is 97.18. The lithium ions are coordinated to pyrrole rings in h 5 modes in Scheme 1.…”

Synthesis and characterization of lithium and yttrium complexes containing tridentate pyrrolyl ligands. Single-crystal X-ray structures of {Li[C4H2N(CH2NMe2)2-2,5]}2 (1) and {[C4H2N(CH2NMe2)2-2,5]YCl2(μ-Cl)·Li(OEt2)2}2 (2) and ring-opening polymerization of ε-caprolactone

“…In 2, some of carbon atoms show disorder. The dual-site disorder pairs: for C(9) and C (12) were fixed at a 0.5/0.5 ratio; for C (13) and C (14) were fixed at a 0.7/0.3 ratio; for C (15) and C(16) were fixed at 0.6/0.4 ratio.…”

“…The molecular structures of g 1 -pyrrolyl lithium complexes have been reported in the literature [14]. Suitable crystals of compound 1 were grown from a saturated diethyl ether solution for structure determination.…”

11 Vanadium, niobium and tantalum

“…ؒ2THF with MeLi and NaHBEt 3 has been studied, and the resultant products have all been characterised by X-ray crystallography. 34 The first tantalasilsesequioxanes have been prepared via amide routes starting from either [Ta(NMe…”