Vyacheslav V. Sushev

Migratory Insertion of the R2P Group into a Nitrogen-Nitrogen Bond : A Novel Type of Rearrangement in Phosphorus-Nitrogen Ligand Chemistry. 3. The Rearrangement of Triphosphinohydrazide Ligand -N(PPh2)-N(PPh2)2 to Triphosphazenide Anion {[(Ph2P-N]2PPh2}-in the Coordination Sphere of Divalent Cobalt and Nickel

Hydrazine dihydrochloride reacts with 3 equiv of Ph2PCl in tetrahydrofuran in the presence of triethylamine to give tris(diphenylphosphino)hydrazine (1) in 70% yield. Each nitrogen atom in 1 has a trigonal-planar environment according to X-ray analysis. Thermolysis of 1 at 130 degrees C results in the formation of two products: bis(diphenylphosphino)amine and octaphenylcyclotetraphosphazene. The interaction of free ligand 1 with NiBr2 affords a simple adduct [(Ph2P)2N-NH-PPh2]NiBr2, while its anionic (hydrazide) form undergoes rearrangement in a coordination sphere of divalent cobalt and nickel involving migratory insertion of the Ph2P group into a nitrogen-nitrogen bond. The reaction of 1 with cobalt bis(trimethylsilyl)amide, [(Me3Si)2N]2Co, yields the complex of phosphazenide-type (Me3Si)2N-Co[(Ph2PN)2PPh2] (2) in 86% yield. A similar reaction of 1 with nikelocene proceeds with substitution of one Cp ring to form durable 18-electron complex CpNi[(Ph2PN)2PPh2] (3).

Nickel(II) and nickel(0) derivatives of bis(diphenylphosphino)amine: [N(PPh2)2]2Ni, (Ph3P)2Ni[(Ph2P)2NH]. Synthesis, characterization, and some properties

Disproportionation of nickel(I) bis(triphenylphosphino)bis(trimethylsilyl)amide, (Ph 3 P) 2 NiN(SiMe 3 ) 2 , in the presence of bis(diphenylphosphino)amine, (Ph 2 P) 2 NH, yields Ni(II) and Ni(0) phosphinoamide complexes: [N(Ph 2 P) 2 ] 2 Ni ( 1 ), (Ph 3 P) 2 Ni[(Ph 2 P) 2 NH] ( 2 ). Ether solution, containing 2 and Ph 3 P (1:2) reacts with dioxygen (one equivalent) to form triphenylphosphinoxide adduct (Ph 3 P) 2 Ni[(Ph 2 P) 2 NH⋯OPPh 3 ] ( 3 ) in high yield. The crystal structures of compounds 1 and 3 have been determined by X-ray diffraction method.

New type of coordination of phosphorus to carbene analogs. p(π)-Complex of 3a,6a-diaza-1,4-diphosphapentalene with germanium dichloride

Abstract3a,6a-Diaza-1,4-diphosphapentalene (1), as a neutral ligand, displays a new type of complexation, such that the lone pair at the phosphorus atom is not involved in the coordination; instead, the 10π-electron system provides two electrons for the coordination bond formation between the phosphorus atom and the metal. The p(π)-type complex–a molecular adduct of 1 with germanium dichloride — was synthesized and completely characterized. This complex is a coordination polymer with short intermolecular Ge—Ge, Ge—P, P—P, P—Cl, and Ge—C contacts.

Chemistry of the phosphorus-nitrogen ligands. Multiple isomeric transformations of the diphosphinohydrazine bearing 8-quinolyl substituent: P→C, P→N, and P→P migrations caused by different factors.

The reaction of 8-quinolylhydrazine with 2 equiv of Ph(2)PCl in the presence of Et(3)N gives 8-[(Ph(2)P)(2)NNH]-Quin (1) (Quin = quinolyl) in 84% yield. The heating of 1 at 130 °C for 1 h in toluene results in migration of the [Ph(2)PNPPh(2)] group to a carbon atom of the quinolyl fragment to form an isomer, 7-(Ph(2)P-N═PPh(2))-8-NH(2)-Quin (2). The same migration is caused by the addition of LiN(SiMe(3))(2) to 1. On the contrary, lithiation of 1 with n-BuLi followed by the addition of ZnI(2) (1:1) affords the aminoquinolyl-phosphazenide dinuclear complex [ZnI(8-Quin-NPPh(2)═N-PPh(2))-κ(3)N,N,P](2) (4), which is a result of P→N migration. Compound 1 itself reacts with ZnI(2) in THF to form 4 and protonated molecule 1·HI, which rearranges to the more stable iminobiphosphine salt (Ph(2)P-PPh(2)═N-NH-Quin-8)·HI. Zinc iodide reacts with 2 equiv of the lithium salt of 1 without rearrangement, to form homoleptic aminoquinolyl zinc complex Zn[{(Ph(2)P)(2)NN-Quin-8}-κ(2)N,N](2) (6). Solutions of 4 and 2 in dichloromethane show luminescence at 510 and 460 nm (quantum yields are 45% and 7%, respectively). DFT calculations were provided for possible isomers and their complexes.

Chemical properties of 3a,6a-diaza-1,4-diphosphapentalene. Addition of polyhalohydrocarbons

Abstract3a,6a-Diaza-1,4-diphosphapentalene (DDP, 1), in contrast to common azaphospholes, readily reacts with polyhalohydrocarbons with the formation of 1,1- or 1,4-addition products at the phosphorus atoms. Dibromomethane gives the substitution product of two bromine atoms [CH2(DDP)2]Br2 (2) and diphosphine (DDP-DDP)Br2 (3) containing a bridging bromine atom. In the course of the reaction of DDP with CF2Br2, two products of sequential substitution of the bromine atoms were isolated, which are 1,4-Br2(DDP) (6) and [CF2(DDP)2]Br2 (7). Tris(pentafluorophenyl)phosphine reacts with DDP at the C—F bond with the formation of 1,1-addition product 8. Compounds 2, 3, 7, and 8 contain hypervalent (tervalent 4-coordinated) phosphorus atoms. X-ray diffraction data indicate that the mutual arrangement of the DDP fragments in compounds 2, 3, and 7 is determined by the non-covalent interaction of one of the bromine atoms simultaneously with two phosphorus atoms of different DDP fragments in such a way that the lines of the N—P bonds converge at this bromine atom.

Adducts of dicoordinated trivalent phosphorus with carbenes

Abstract1,4-Dichloro-3a,6a-diaza-1,4-diphosphapentalene reacts with sodium acetylacetonate to form an adduct of diacylcarbene with trivalent dicoordinated phosphorus. In solution this adduct dimerizes according to the head-to-head type. The phosphorus atoms undergo transformation from the hypervalent state (in the adduct), in which the lone electron pair on the phosphorus atom is not involved in the formation of additional bonds with this phosphorus(III) atom, to the pentavalent pentacoordinated and trivalent tricoordinated state (in the dimer).

Reactions of cyclohexene-annulated 3а,6а-diaza-1,4-diphosphapentalene with sulfur, selenium, and CS 2 : structural features of zwitterionic products

The reactions of b- and f-face cyclohexene-annulated 3a,6a-diaza-1,4-diphosphapentalene (CADDP) with elemental sulfur and selenium result in the addition of two chalcogen atoms to one phosphorus atom of CADDP. A specific feature of these structures is that the diazadiphosphapentalene skeleton retains planar geometry, with a significant elongation of the N—P bond. These compounds are zwitterions, as evidenced by their electronic structures, with considerable delocalization of the negative charge in the PS2 (PSe2) moieties and of the positive charge in the diazaphosphole ring. The reaction of CADDP with carbon disulfide is a more complicated process accompanied by the decomposition of the CS2 molecule to form a molecule containing three structurally different CADDP moieties, one of which is a stabilized carbene complex.

Exchange of halogens in the 3a,6a-diaza-1,4-diphosphapentalene derivatives: Crystal structures of iodides

Abstract1,4-Dichloro-3a,6a-diaza-1,4-diphosphapentalene (II) easily exchanges halogen with methyl iodide to form the corresponding 1,4-diiodo derivative (V) in a quantitative yield. The reaction of compound II with diiodine (1 equiv) affords compound III, the crystal structure of which contains 55% II and 45% V. Under the conditions of iodine excess (1 : 3), a ionic compound (IV) is formed, the crystal of which contains alternating layers consisting of planar networks [I2I3]− and heterocyclic cations [DDP–Cl]+. For the crystallographic information for compounds III–V, see CIF files CCDC no. 1560 410 (V), 1560 411 (III), and 1560 412 (IV).

Reaction of benzylidenetriphenylphosphorane with 1,4-dichloro-3а,6а-diaza-1,4-diphosphapentalene

The transylidation between 1,4-dichloro-3a,6a-diaza-1,4-diphosphapentalene and benzylidenetriphenylphosphorane (Ph3P=CHPh) results in either mono- or disubstitution of chlorine atoms by the Ph3P=C(Ph) group depending on the reactant molar ratio. In the crystal, the monosubstituted product has the planar diazadiphosphapentalene ring and the P—Cl ionic bond. The 31P NMR spectra of this compound exhibit a strong solvent-dependent behavior, which indicates that it exists both in the ionic form (in CH2Cl2, MeCN) and the molecular form (in THF). In the disubstituted product, the diazadiphosphapentalene skeleton is non-planar and is bent along the N—N bond.

Interaction of Azobenzene and Benzalaniline with Strong Amido Bases

The interaction of azobenzene with lithium dicyclohexylamide (Cy2NLi) in THF or Et2O afforded the ion-radical salt of azobenzene (1) structurally characterized for the first time and dicyclohexylaminyl radical, which begins a novel chain of transformations leading eventually to the imino-enamido lithium complex (3). Benzalaniline, being a relative of azobenzene, reacted with Cy2NLi without electron transfer by a proton-abstraction mechanism to form the dilithium salt of N(1),N(2),1,2-tetraphenylethene-1,2-diamine quantitatively.