The First Structurally Characterized Metal (κ²N,P)-Phosphinohydrazides: The Key to Understanding the Intramolecular Rearrangement R₂P−NR′−NR′−M → R′N═PR₂−NR′−M. Metalloderivatives of Diisopropylphosphinohydrazines: Synthesis and Properties

Abstract

A number of novel phosphinohydrazines, iPr(2)P-NPh-NPh-H (1), iPr(2)P-NH-NH-PiPr(2) (2), iPr(2)P-NMe-NH-PiPr(2) (3), and H-NMe-NH-PiPr(2) (4), were prepared and characterized. The interaction of 1 with 1 equiv of n-BuLi afforded a complex compound [Li(DME)(3)][Li{(NPh-NPh-PiPr(2))-kappaN}(2)] (5). The reaction of 5 with NiBr(2) resulted in the formation of the first stable transition metal phosphinohydrazide [Ni{(NPh-NPh-PiPr(2))-kappa(2)N,P}(2)] (6). Similarly, the cobalt(II) derivative [Co{(NPh-NPh-PiPr(2))-kappa(2)N,P}(2)] (7) was prepared by the reaction of 1 with Co[N(SiMe(3))(2)](2). An X-ray study reveals formation of the complexes containing elongated N-N bonds (1.443(1), 1.466(2), and 1.470(2) A for 5, 6, and 7, respectively) as compared with the starting material 1 (1.407(1) A). Nickel phosphinohydrazide 6 has a square-planar cis configuration; the cobalt complex 7 possesses a square-planar centrosymmetric trans configuration. The half-sandwich nickel(II) complex [CpNi{(NPh-NPh-PiPr(2))-kappa(2)N,P}] (8) was prepared by prolonged heating of phosphinohydrazine 1 with NiCp(2) in toluene. The lithiation of 3 with n-BuLi resulted in the formation of an iminophosphoranate [LiN=PiPr(2)-NMe-PiPr(2)] (13) (in situ), which is the product of insertion of a PiPr(2) group into the nitrogen-nitrogen bond. The hydrolysis of 13 followed by the addition of CoCl(2) gave the phosphino-iminophosphoranato complex [CoCl(2){(HN=PiPr(2)-NMe-PiPr(2))-kappa(2)N,P}] (15) according to X-ray investigation. The phosphinohydrazine 3 reacted with FeX(2) in toluene to form adducts (1:1) [FeX(2){(PiPr(2)-NMe-NH-PiPr(2))-kappa(2)P,P'}] (X = Cl (9), Br (10)), while CoCl(2) gave the complex salt [{Co(PiPr(2)-NMe-NH-PiPr(2))-kappa(2)P,P'}(2)(mu-Cl)(3)][CoCl(3)(THF)] (11). A THF solution of complex 11 shows thermochromic behavior.

Four cluster-based coordination polymers built on a semirigid tripod tricarboxylate ligand

“…The Mn-O-Mn angle are from 56.42(6) to 180°, and the O-Mn-Cl angles are 84.29(5) to 173.05°, which are comparable with those reported in the literature 14,15. The bond valence sum 16 for Mn120 (1.93), Mn2 (2.06), Mn3 (2.01) and Mn4 (1.62) are in accordance with the expected values.The two crystallographically independent L 3− ligands adopt a distorted trigonal coordination geometry, with the angles between three arms ranging from 97.10(3) to 134.31(9)°. They exhibit 25 different coordination modes: one ligand coordinates to six neighboring Mn atoms (Mn1 and Mn2) in a chelating mode; the other coordinates to six Mn atoms (Mn3 and Mn4) in a bismonodentate mode.…”

“…Because compounds 1 and 3 possess unusual heptanuclear 20 clusters of Mn(II) and Co(II) ions, respectively, their magnetic properties were studied by variable-temperature magnetic measurements. The measurements were performed on polycrystalline samples in the range of 1.8 to 300 K under a field of 2 kOe.…”

“…3 These materials are 20 usually constructed from the combination of metal ions with multidentate organic ligands through covalent metal-ligand bonding. The resultant networks are highly dependent on the geometry and coordination environment of the metal ions and ligands.…”

P-Stereogenic bisphosphines with a hydrazine backbone: from N–N atropoisomerism to double nitrogen inversion

“…To improve the stability of the resulting ligands, we derivatized 4 by alkylation on both nitrogen atoms. 11 The methylation of 4 was achieved by deprotonating hydrazine nitrogen atoms with sodium hydride and adding an excess of methyl iodide at 55 1C (Scheme 3). The dimethyl derivative 5 was isolated in 90% yield.…”

The rearrangement of phosphitohydrazide ligand [(ArO)2P–NPh–NPh–] into iminophosphoranate anion [(PhNP(OAr)2–NPh–] {(ArO)2P = [CH2(tBuMeC6H2O)2P]} in coordination sphere of divalent cobalt

“…Note, however, that similar phosphinohydrazide complexes, containing more hindered diisopropylphosphino group, (i-Pr 2 PNPh-NPh) 2 M (M = Co, Ni), do not undergo rearrangement [4] whereas lithium salt of bis(diisopropylphosphine)methylhydrazine, (i-Pr 2 P-NMe-NLi-PiPr 2 ) rearranges quickly to iminophosphoranate salt i-Pr 2 P-NMe-PiPr 2 @NLi [4]. The reason of such differences still is not clear in details.…”