First-Row Transition Metal−Halide Complexes Supported by a Monoanionic [N₂P₂] Ligand

Abstract

Metal-halide complexes of a multidentate monoanionic ligand tBuN(H)SiMe2N(CH2CH2PiPr2)2, H[N2P2], with Ti, V, Cr, Mn, Fe, Co, and Ni have been isolated and characterized. X-ray crystallographic studies were performed on [N2P2]TiCl2 (3), [N2P2]CrCl2 (5), [N2P2]MnCl (6), [N2P2]FeCl (7), [N2P2]CoCl (8), and [N2P2]NiBr (9), and the results revealed that the [N2P2] ligand exhibits considerable flexibility in the manner in which it binds to first-row metals and that three distinct coordination modes are observed: kappa3-N2P (Ti), kappa3-NP2 (Mn, Fe, Co), and kappa4-N2P2 (Cr, Ni). Electrochemical (CV) data and room-temperature magnetic susceptibilities are also described.

Chloridobis{N-[(dimethylamino)dimethylsilyl]-2,6-dimethylanilido-κ2N,N′}titanium(III)

“…It suggests the former is much tighter than the latter. They are different from corresponding bond lengths 1.972 (4)Å and 2.356 (6)Å in a related amido Ti(III) compound reported by Chomitz et al (2008).…”

“…It is interesting that the valence of Ti has changed from IV to III. Similar situation could be found in Ovchinnikov's work (Ovchinnikov et al, 1993) and other - Chomitz et al, 2008). The driving factors for reduction will be investigated in further research.…”

“…For related titanium compounds, see: Ovchinnikov et al (1993); Chomitz et al (2008). For amido titanium compounds as olefin polymerization catalyts, see: Alesso et al (2008); Oakes et al (2004); Tabernero et al (2009).…”

Use of Tetradentate Monoanionic Ligands for Stabilizing Reactive Metal Complexes

“…[60][61][62] Given this precedence, a "mixed-donor" tri- . [63] All but the V analogue were structurally characterized, and one feature of these complexes that was revealed from the X-ray diffraction studies was the different coordination modes observed in the solid-state: k 3 -N 2 P, k 3 -NP 2 , and k 4 -N 2 P 2 . The electronic and geometric preferences of the metal center appear to dictate the coordination mode of the ligand with more electropositive metals such as Ti preferring coordination of the two harder nitrogen donors over the two phosphine donors (k 3 -N 2 P).…”

“…Li[N 2 P 2 ] was shown to be a useful starting material for the synthesis of a wide range of first‐row transition‐metal compounds by means of salt metathesis reactions. The first‐row metal‐halide complexes [TiCl 2 (N 2 P 2 )], [VBr 2 (N 2 P 2 )], [CrCl 2 (N 2 P 2 )], [MnCl(N 2 P 2 )], [FeCl(N 2 P 2 )], [CoCl(N 2 P 2 )], and [NiBr(N 2 P 2 )] were synthesized and isolated in good yields following the reaction of the metal halide starting material [MX 3 (thf) 3 ] (M=Ti, V, Cr; X=Cl, Br) or MX 2 (M=Mn, Fe, Co, Ni; X=Cl, Br) with Li[N 2 P 2 ] 63. All but the V analogue were structurally characterized, and one feature of these complexes that was revealed from the X‐ray diffraction studies was the different coordination modes observed in the solid‐state: κ 3 ‐N 2 P, κ 3 ‐NP 2 , and κ 4 ‐N 2 P 2 .…”