Łukasz Ponikiewski

Reactivity of Phosphanylphosphinidene Complex of Tungsten(VI) toward Phosphines: A New Method of Synthesis of catena-Polyphosphorus Ligands.

The reactivity of an anionic phosphanylphosphinidene complex of tungsten(VI), [(2,6-i-Pr2C6H3N)2(Cl)W(η(2)-t-Bu2P═P)]Li·3DME toward PMe3, halogenophosphines, and iodine was investigated. Reaction of the starting complex with Me3P led to formation of a new neutral phosphanylphosphinidene complex, [(2,6-i-Pr2C6H3N)2(Me3P)W(η(2)-t-Bu2P═P)]. Reactions with halogenophosphines yielded new catena-phosphorus complexes. From reaction with Ph2PCl and Ph2PBr, a complex with an anionic triphosphorus ligand t-Bu2P-P((-))-PPh2 was isolated. The main product of reaction with PhPCl2 was a tungsten(VI) complex with a pentaphosphorus ligand, t-Bu2P-P((-))-P(Ph)-P((-))-P-t-Bu2. Iodine reacted with the starting complex as an electrophile under splitting of the P-P bond in the t-Bu2P═P unit to yield [(1,2-η-t-Bu2P-P-P-t-Bu2)W(2,6-i-Pr2C6H3N)2Cl], t-Bu2PI, and phosphorus polymers. The molecular structures of the isolated products in the solid state and in solution were established by single crystal X-ray diffraction and NMR spectroscopy.

Reactions of Lithiated Diphosphanes R2P–P(SiMe3)Li (R = tBu and iPr) with [MeNacnacTiCl2·THF] and [MeNacnacTiCl3]. Formation and Structure of TitaniumIII and TitaniumIV β-Diketiminato Complexes Bearing the Side-on Phosphanylphosphido and Phosphanylphosphinidene Functionalities

β-Diketiminate complexes of TiIII-containing phosphanylphosphido ligands [MeNacnacTi(Cl){η2-P(SiMe3)-PR2}] (MeNacnac- = [Ar]NC(Me)CHC(Me)N[Ar]; Ar = 2,6-iPr2C6H3) were prepared by reactions of [MeNacnacTiCl2·THF] with lithium derivatives of diphosphanes R2P-P(SiMe3)Li (R = tBu, iPr) in toluene solutions. Surprisingly, reactions of [MeNacnacTiCl2·THF] with R2P-P(SiMe3)Li in THF solutions led to TiIV complexes containing phosphanylphosphinidene ligands [MeNacnacTi(Cl)(η2-P-PtBu2)] via an autoredox path involving a migration of a nitrene NAr from the Nacnac skeleton to the Ti centers. Solid-state structures of [MeNacnacTi(Cl){η2-P(SiMe3)-PtBu2}] (1a) and [MeNacnacTi(Cl)(η2-P-PtBu2)] (two isomers 2a1, 2a2) together with [MeNacnacTi(Cl){η2-P(SiMe3)-PiPr2}] (1b) and [MeNacnacTi(Cl)(η2-P-PiPr2)] (2b) were established by the single-crystal X-ray diffraction and display clearly side-on geometry of the (Me3Si)P-PR2 and P-PR2 moieties in the solid state. Phosphanylphosphinidene complexes [MeNacnacTi(Cl)(η2-P-PR2)] indicate that the 31P NMR resonances of phosphinidene P atoms appear at a very low field in solution and in the solid state.

3-[(E)-2-(5,7-Dichloro-8-hydroxy-quinolin-2-yl)vin-yl]-4-hydroxy-phenyl acetate.

The two symmetry independent molecules of the title compound, C19H13Cl2NO4, show similar conformations with the acetyl group twisted strongly relative to the remaining, virtually flat (r.m.s. deviations = 0.0173 and 0.0065 Å), part of the molecule. The hydroxyl groups of the 8-hydroxyquinoline residues are involved in intramolecular O—H⋯N hydrogen bonds, which, in one case, forms a part of a three-center interaction. Intermolecular O—H⋯O hydrogen bonds assemble the molecules into a one-dimensional polymeric structure extended along the a axis. The 4-hydroxyphenyl group of one molecule forms an O—H⋯O hydrogen bond, in which the hydroxyl H atom is disordered, with its inversion center counterpart.

Propeller-Like Chirality of Methyl-Tris (2,6-diisopropylphenoxy)Silylsulfide

Two new methylsilylsulfides are synthesized. Propeller-like chirality is described for triaryloxysilanethiol and its methyl derivative. S-methylation of the silanethiol lowers the overall symmetry of the unit cell.

1,1,2,2-Tetra-kis(diisopropyl-amino)diphosphane.

In the title compound, C24H56N4P2, the distance between the P atoms [2.2988 (8) and 2.3013 (13) Å in the major and minor occupancy components, respectively] is one of the longest reported for uncoordinated diphosphanes. The whole molecule is disordered over two positions with site-occupation factors of 0.6447 (8) and 0.3553 (8). The structure adopts the synperiplanar conformation in the solid state [N—P—P—N torsion angle = 14.7 (5)°].

Synthetic, Structural, and Spectroscopic Characterization of a Novel Family of High-Spin Iron(II) [(β-Diketiminate)(phosphanylphosphido)] Complexes

This work describes a series of iron(II) phosphanylphosphido complexes. These compounds were obtained by reacting lithiated diphosphanes R2PP(SiMe3)Li (R = t-Bu, i-Pr) with an iron(II) β-diketiminate complex, [LFe(μ2-Cl)2Li(DME)2] (1), where DME = 1,2-dimethoxyethane and L = Dippnacnac (β-diketiminate). While the reaction of 1 with t-Bu2PP(SiMe3)Li yields [LFe(η1-Me3SiPP-t-Bu2)] (2), that of 1 with equimolar amounts of i-Pr2PP(SiMe3)Li, in DME, leads to [LFe(η2-i-Pr2PPSiMe3)] (3). In contrast, the reaction of 1 with (i-Pr2N)2PP(SiMe3)Li provides not an iron-containing complex but 1-[(diisopropylamino)phosphine]-2,4-bis(diisopropylamino)-3-(trimethylsilyl)tetraphosphetane (4). The structures of 2-4 were determined using diffractometry. Thus, 2 exhibits a three-coordinate iron site and 3 a four-coordinate iron site. The increase in the coordination number is induced by the change from an anticlinal to a synclinal conformation of the phoshpanylphosphido ligands. The electronic structures of 2 and 3 were assessed through a combined field-dependent 57Fe Mössbauer and high-frequency and -field electron paramagnetic resonance spectroscopic investigation in conjunction with analysis of their magnetic susceptibility and magnetization data. These studies revealed two high-spin iron(II) sites with S = 2 ground states that have different properties. While 2 exhibits a zero-field splitting described by a positive D parameter (D = +17.4 cm-1; E/D = 0.11) for 3, this parameter is negative [D = -25(5) cm-1; E/D = 0.15(5)]. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations provide insights into the origin of these differences and allow us to rationalize the fine and hyperfine structure parameters of 2 and 3. Thus, for 2, the spin-orbit coupling mixes a z2-type ground state with two low-lying {xz/yz} orbital states. These interactions lead to an easy plane of magnetization, which is essentially parallel to the plane defined by the N-Fe-N atoms. For 3, we find a yz-type ground state that is strongly mixed with a low-lying z2-type orbital state. In this case, the spin-orbit interaction leads to a partial unquenching of the orbital momentum along the x axis, that is, to an easy axis of magnetization oriented roughly along the Fe-P bond of the phosphido moiety.

The reactivity of 1,1-dichloro-2,2-di-tert-butyldiphosphane towards lithiated metal carbonyls: a new entry to phosphanylphosphinidene dimers

Reactions of [Cp*(OC)3M]Li (Cp* = C5Me5, M = Mo, W) towards t-Bu2P-PCl2 lead to the formation of phosphanylphosphinidene dimers [Cp*(OC)3M(η(2)-t-Bu2P-P)]2 in fairly good yields. The formation of a tetraphosphorus ligand proceeds via reductive dimerization of t-Bu2P-P units. NMR, X-ray investigations and DFT calculations show that the resulting tetraphosphorus ligand has a structure of dication t-Bu2P(+)=P-P=P(+)t-Bu2.

Synthesis, structural and spectroscopic properties of asymmetric Schiff bases derived from 2,3-diaminopyridine

Two Schiff base derivatives, 4-(2-amino-3-pyridyliminomethyl)phenol (I) and 3-(2-amino-3-pyridyliminomethyl)nitrobenzene (II), were synthesised and characterised by spectroscopy. The structure of I was determined by single crystal X-ray diffraction studies. The asymmetric Schiff base derived from 2,3-diaminopyridine selectively recognise transition and heavy metal cations, and some anion. Ligands I and II form stable complexes with Cu2+, Zn2+, Pb2+, Al3+ whereas ligand I also binds F~ ions. The stoichiometry for the host: cation is 1: 1 and 2: 1. The addition of F~ ion in CH3CN to ligand I causes a colour change of the solution from colourless to yellow. The binding behaviour of ligand I towards several ions was investigated using density functional theory calculations.

[N,N'-Bis(2,6-diisopropyl-phen-yl)pentane-2,4-diamine-(1-)-2κN,N']-μ(2)-chlorido-1:2κCl:Cl-chlorido-2κCl-bis-(1,2-di-methoxy-ethane-1κO,O')iron(II)lithium.

In the title compound, [FeLi(C29H41N2)Cl2(C4H10O2)2], the FeII atom is coordinated by two N and two Cl atoms, generating a distorted FeN2Cl2 tetrahedral geometry. Additionally, one of the chloride atoms bridges to a lithium ion, which is solvated by two dimethoxyethane molecules and is coordinated in a distorted trigonal-bipyramidal environment. The central Fe, Cl (× 2) and Li atoms are coplanar with a maximum deviation of 0.034 Å.

Bis(diethyl-amido-κN)(diethyl-amine-κN)bis-(2,6-diisopropyl-phenyl-amido-κN)zirconium(IV).

In the title compound, [Zr(C12H18N)2(C4H10N)2(C4H11N)] or [Zr(HNC6H3 iPr2)2(NEt2)2(HNEt2)], which was obtained by the reaction of Zr(NEt)4 with iPr2C6H3NH2, the ZrIV atom is in a trigonal–bipiramidal geometry in which the N atoms from two iPr2C6H3NH and one NEt2 ligand occupy the equatorial positions, and the N atoms of an NEt2 and an Et2NH ligand occupy the apical positions. An intramolecular N—H⋯N contact occurs. There are two independent molecules in the asymmetric unit.