Aryl- and acetylene-nickel(I) complexes

Reduction of various pentafluorophenylnickel(II) complexes in the presence of phosphines gives unstable nickel(I) compounds but Ni(C₆F₅)(CO)₂(PPh₃)₂ is isolated in the presence of CO. Similar NiR(CO)₂(PPh₃)₂ (R = C₆F₅,C₆Cl₅, 2,3,5,6-C₆Cl₄H) are obtained by reaction of the halogenonickel(I) complex with MgRBr or LiR. Reduction of NiX₂L₂ in the presence of acetylenes gives [NiXL₂]₂(μ-PhCCR) (R = H, X = Cl and R = Ph, X = Cl, Br) when L = P-n-Bu₃ but only NiX(PPh₃)₃ are recovered when L = PPh₃. No reaction with the alkyne is observed for [NiX(PPh₃)₂]_n but [NiCl(PPh₃)]_n reacts with RCCR′ to give paramagnetic NiCl(PPh₃)(CRCR′) (R = Ph, R′= H, COOEt), diamagnetic [NiCl(PPh₃)]₂(μ-PhCCPh) and cyclotrimerization when R = R′ = COOMe. Chemical and structural behaviour of the new nickel(I) complexes is described.     

Pentafluorothiophenolate derivatives of cobalt(II) and nickel(II). The molecular structure of [Ni(SC6F5)2Ph2PCH2CH2PPh2]

Summary The tetrahedral compounds [Co(SC₆F₅)₂L] (L=Ph₂P(CH₂) _n PPh₂,n=1, 2 and 3) and the squareplanar compound [Ni(SC₆F₅)₂(PhPCH₂CH₂PPh₂)] have been obtained by mathematical reactions of [MX₂L] (M=Co or Ni, X=Cl or Br) and Pb(SC₆F₅)₂. The reaction of pentacoordinate [CoCl(Ph₂PCH₂CH₂PPh₂)₂]⁺ and the lead salt yields [CoCl₂L] and [Co(SC₆F₅)₂L]. Magnetic moments, u.v. data (both in solution and solid state) and the crystal and molecular structure of the nickel compound are reported.     

Benzylnickel(II)-Komplexe und ihre Reaktionen

Benzyl Nickel(II) Complexes and their Reactions By the oxydative addition of p-substituted benzyl chlorides to (Ph₃P)₂Ni(C₂H₄) at ?20°C the violet nickel(II) complexes (Ph₃P)₂Ni(p-CH₂C₆H₄R)Cl (R ? CN, COOH, CH₃, Cl) are, formed. In water containing solutions the carbonic acid (Ph₃P)₂Ni(p-CH₂C₆H₄COOH)Cl is rearranged to the corresponding p-methylbenzoate. With carbon dioxide the complexes (Ph₃P)₂Ni(p? CH₂C₆H₄R)Cl react like Grignard compounds. Diphenyl ethine and butadien-1,3 are inserted in the Ni—C bond at room temperature. Substituted nickel-σ-vinyl or π-allyl complexes are obtained. The reactivity of the nickel-σ-benzyl compounds is compared with that of other nickel(II)-alkyl compounds.     

Synthesis and characterization of nickel(II) maltolate complexes containing ancillary bisphosphine ligands

Cationic nickel(II) complexes containing chelating O,O′-donor maltolate or ethyl maltolate ligands in conjunction with bidentate bisphosphine ligands Ph₂P(CH₂) _n PPh₂ were prepared by a one-pot reaction starting from nickel(II) acetate, bisphosphine, maltol (or ethyl maltol), and trimethylamine, and isolated as their tetraphenylborate salts. An X-ray structure determination of [Ni(maltolate)(Ph₂PCH₂CH₂PPh₂)]BPh₄ shows that the maltolate ligand binds asymmetrically to the (slightly distorted) square-planar nickel(II) center. The simplicity of the synthetic method was extended to the synthesis of the known platinum(II) maltolate complex [Pt(maltolate)(PPh₃)₂]BPh₄ which was obtained in high purity.     

Bis(diphenylphosphano)alkan- und 1-(Diphenylphosphano)-2-(2-pyridino)ethan-N-Arylsulfinylamin-Nickel(0)-Komplexe

Bis(diphenylphosphano)alkane- and 1-Diphenylphosphano-2-(2-pyridino)ethane-N-arylsulfinylamine Nickel(0) Complexes Synthesis and properties of the bis(diphenylphosphano)alkane-N-phenyl-sulfinylamine-nickel(0) complexes [Ni{Ph₂P(CH₂)_nPPh₂}(PhNSO)] (n = 2 dppe, n = 3 dppp, n = 4 dppb) as well as of the 1-(diphenylphosphano)-2-(2-pyridino)ethane nickel(0) complexes [Ni(dpppe)₂], [Ni(dpppe)(p-TolNSO)] and [Ni(dpppe)(PPh₃)₂] are described. These compounds have been characterized by i. r. and ³¹P n.m.r. spectroscopy. The N-arylsulfinylamine ligands are η²-(N, S)-side on coordinated.     

Halonickel(I) complexes

Summary The reduction of nickel(II) halides with NaBH₄ in the presence of different ligands, L=PPh₃, AsPh₃, SbPh₃, has been studied. With a molar ratio L/Ni=3, new complexes NiX(SbPh₃)₃, X=Cl, Br, I, were obtained. With a molar ratio L/Ni=2, dimeric species [NiXL₂]₂, X=Cl, Br, I; L=PPh₃, AsPh₃, SbPh₃, were isolated. They are unstable and decompose easily in the solid and rapidly in solution, so that pure samples were only identified for X=Cl, L=PPh₃, AsPh₃, SbPh₃; X=Br, L=PPh₃ and X=I, L=PPh₃. With a molar ratio L/Ni=1, complexes [NiXL]_n (probably polymeric) were obtained. They are very unstable and pure samples could only be isolated when X=Cl, L=PPh₃. Impure substances containing variable amounts of decomposition products were obtained in all the remaining cases. The chemical and structural behaviour of these complexes is discussed.     

Crystal and molecular structures of (η-xanthene)- (η-cyclopentadienyl)iron(II) hexafluorophosphate and (η-2-methylthianthrene)(η-cyclopentadienyl)iron(II) hexafluorophosphate

The neutral complexes (η⁵-C₅H₅NiXL (X = Cl, L = PPh₃ (I); L = PCy₃ (II); X = Br, L = PPh₃ (III); L = PCy₃ (IV); X = I, L = PPh₃ (V); L = PCy₃ (VI)) have been obtained by treating NiX₂L₂ with thallium cyclopentadienide. The same reaction in the presence of TlBF₄ gives cationic derivatives [(η⁵-C₅H₅)NiL₂]BF₄ (L = 2PPh₂Me (VII); L = dppe (VIII)), whereas mononuclear complexes containing two different ligands (L₂ = PPh₃ + PCy₃ (IX)) or dinuclear [(η⁵-C₅H₅)Ni(PPh₃)]₂dppe(BF₄)₂ (X) are obtained from the reaction of III with TlBF₄ in the presence of a different ligand. Reduction of cationic complexes with Na/Hg gives very unstable nickel(I) derivatives (η⁵-C₅H₅)NiL₂, which could not be isolated purely. Similar reduction of neutral complexes under CO gives a mixture of decomposition products containing [(η⁵-C₅H₅)Ni(CO)]₂ and nickel(o) carbonyls, whereas in the presence of acetylenes, dinuclear [(η⁵-C₅H₅)Ni]₂(RCCR′) (R = R′ = Ph; R = Ph, R′ = H) are obtained.     

Nickel(II) di(pentyl)dithiocarbamates with P ligands

Ni(II) di(pentyl)dithiocarbamates of composition [Ni(Pe₂dtc)₂], [NiX(Pe₂dtc)(PPh₃)] (X = Cl, Br, I, NCS), [Ni(NCS)(Pe₂dtc)(PBut₃)], [Ni(Pe₂dtc)(PPh₃)₂]ClO₄ and [Ni(Pe₂dtc)(PPh₃)₂]PF₆ (Pe₂dtc = di(pentyl)dithio-carbamate, PPh₃ = triphenylphosphine, PBut₃ = tributylphosphine) have been synthesized. The complexes have been characterized by the usual methods. X-ray structure analyses confirmed the nature of [NiI(Pe₂dtc)(PPh₃)] and [Ni(Pe₂dtc)(PPh₃)₂]ClO₄ complexes.     

Zur Oxydation von Gemischtligand-Nickel(0)-Komplexen mit organischen Halogeniden

Oxidation of Mixed Ligand Nickel(0) Complexes by Organic Halides The oxidation of (dipy)Ni(PPh₃)₂ by alkyl and aryl iodides or bromides affords the nickel(I) complexes (dipy)Ni(PPh₃)X (X = Br, I). No normal products of oxidative addition are obtained. But in the case of methyl and ethyl halides complexes of the type (dipy)NiR₂ are formed as intermediates. Basing on the identified final products and on the correalation between the reactivity of the organic halides and their polarographic half wave potentials a mechanism of the reaction is proposed. The first step is a charge transfer from nickel(0) to the organic halide. Further synthesis, reactions, and the ESR-spectra of the complexes (dipy)Ni(PPh₃)X and a synthesis of (dipy)Ni(CH₂Ph)₂ are described. Experiments to prepare pure (dipy)Ni(PPh₃)Cl had no success.     

Platinum group metal functionalized phosphine complexes. Part 2. Phosphinoamide rhodium(I), iridium(I), palladium(II) and platinum(II) complexes

Summary Rhodium(I), iridium(I), palladium(II) and platinum(II) complexes of the phosphinoamide ligands, Ph₂PCH₂CONHR (R = H, HDPA; Me, MDPA; Ph, PDPA) were prepared and characterized by using conductivity data, i.r., ¹H and ³¹P(H) n.m.r. spectral data. Reaction of the ligands with MCl(PPh₃)₃ and MCl(CO)(PPh₃)₂ (M = Rh, Ir) in CH₂Cl₂ under reflux lead to the formation of MCl(PPh₃)₂ [Ph₂PCH₂C(O)NHR] and MCl(CO)(PPh₃)[Ph₂PCH₂–C(O)HNR] respectively. The reaction of either K₂MCl₄ or cis-MCl₂(PPh₃)₂ affords complexes of the type cis-MCl₂[Ph₂PCH₂C(O)NHR]₂ (M = Pd, Pt). A similar product results even from the reaction of phosphinoamides with cis-platin. Possible structures are proposed for the complexes based on their physicochemical data     

Nickel(II)- und Kobalt(II)-Komplexe des trans-2-Äthylmercapto-cyclohexyl-phenylphosphins

Preparation and properties of nickel(II) and cobalt(II) chelates of the bidentate ligand trans-2-ethylthio-cyclohexyl-phenylphosphine (ÄMCPP) are described. Three types of nickel(II) complexes have been obtained from ÄMCPP: the four-coordinated, square planar [Ni(ÄMCPP)₂]X₂ (X = J, Br, ClO₄); five-coordinated [Ni(ÄMCPP)₂X]X (X = Cl, NCS), [Ni(ÄMCPP)₂X]BPh₄ (X = Cl, NCS) and the octahedral [Ni(ÄMCPP)₂Cl₂]. Cobalt(II) forms tetrahedral 1.1-[Co(ÄMCPP)X₂] (X = Br, Cl) and 1.2-Co(ÄMCPP)₂X₂(X = Br, Cl, NCS) complexes. All compounds were characterized by electronic reflectance and absorption spectra, conductivity and magnetic measurements.     

Ditertiary phosphine complexes of (ν-allyl)dicarbonylmolybdenum(II) and -tungsten(II)

Compounds of the type [XM(CO)₂(ν-allyl)L₂] (where X = Cl and Br; M = Mo and W; L₂ = Ph₂PCH₂PPh₂ and Ph₂ PCH₂CH₂PPh₂) have been prepard from the corersponding MeCN complexes. The spectral properties of these compounds and the effects of chelate rign size on ³¹P coordination shifts and J(¹⁸³W—³¹P) have been investigated.     

Nickel (II) complexes supported by a fluorinated β‐diketiminate backbone ligand: synthesis,catalytic activity toward norbornene polymerization,and the oxygenated species

The reaction of the lithium salt of backbone fluorinated β‐diketiminate ligands, ArNC(CF₃)CHC(CF₃) NArLi, with trans‐[NiCl(Ph)(PPh₃)₂] gives nickel (II) complexes, ArNC(CF₃)CHC(CF₃)NAr(Ph) (PPh₃)Ni (Ar = 2, 6‐Me₂C₆H₃: 1 ; 2, 6‐ⁱPr₂C₆H₃: 2 ). When activated by methylaluminoxane (MAO), both complexes polymerize norbornene rapidly via a vinyl‐type polymerization mechanism. Treatment of nickel complex 1 with oxygen gives rise to intramolecular aerobic hydroxylation. The oxygenated species 3 was characterized by X‐ray crystallography. Copyright © 2006 John Wiley & Sons, Ltd.     

Heterodinukleare Cobalt(II)‐, Nickel(II)‐, Kupfer(II)‐, Zink(II)und Palladium(II)‐Komplexe mit einem makrocyclischen Liganden vom Schiff‐Basen‐Typ: Synthesen und Strukturen

Complexes with Macrocyclic Ligands. IV. Heterodinuclear Cobalt(II), Nickel(II), Copper(II), Zinc(II) and Palladium(II) Complexes with a Macrocyclic Ligand of Schiff‐Base Type: Syntheses and Structures The synthesis and properties of nickel(II), copper(II), and palladium(II) complexes, [ML^Ph] ( 3 ; L^Ph = N,N′‐phenylene‐bis(3‐formyl‐5‐tert.‐butyl‐salicylaldimine)), are described. These neutral mononuclear complexes react with metal(II) perchlorate and 1,3‐propylenediamine to form heterodinuclear, macrocyclic, cationic complexes of the type [MM′(L^Ph,3)]²⁺ ( 4 ; M = Ni, Cu, Pd; M′ = Co, Cu, Zn). The structures of the five new compounds [NiCo(L^Ph,3)](ClO₄)₂, [NiCu(L^Ph,3)](ClO₄)₂, [CuCu(L^Ph,3)](ClO₄)₂, [CuZn(L^Ph,3)](ClO₄)₂, and [PdCu(L^Ph,3)](ClO₄)₂ were determined by X‐ray diffraction.     

Schwefeldioxid als Ligand und Synthon. XIII. Reaktionen von Isocyanid-tris(triphenylphosphan)nickel(0)-Komplexen mit Schwefeldioxid und N-p-Tolylsulfinylamin

Sulfur Dioxide as Ligand and Synthon. XIII. Reactions of Isocyanide-tris(triphenylphosphane)nickel(0) Complexes with Sulfur Dioxide and N-p-tolylsulfinylamine Reactions of the isocyanide-tris(triphenylphosphane)-nickel(0) complexes [(RNC)Ni(PPh₃)₃] (R = ^tBu, Cy, PhCH₂, p-TosCH₂) with SO₂ and p-TolNSO are described. The sulfur dioxide and N-p-tolylsulfinylamine complexes obtained by PPh₃ ligand substitution have been characterized by means of i.r. and ³¹P n.m.r. spectra. The X-ray crystal structure of [(Ph₃P)₂(CyNC)Ni(SO₂)] · 0.5 PhMe and (Ph₃P)(^tBuNC)Ni(η²-p-TolNSO) have been determined.     

N‐(2‐Hydroxyethyl)‐N‐methyldithiocarbamato Complexes of Nickel(II) with Phosphorus Donor Ligands

Planar nickel(II) complexes involving N‐(2‐Hydroxyethyl)‐N‐methyldithiocarbamate, such as [NiX(nmedtc)(PPh₃)] (X = Cl, NCS; PPh₃ = triphenylphosphine), and [Ni(nmedtc)(P‐P)]ClO₄(P‐P = 1,1‐bis(diphenylphosphino)methane(dppm); 1,3‐bis(diphenylphosphino)propane (1,3‐dppp); 1,4‐bis(diphenylphosphino)butane(1,4‐dppb) have been synthesized. The complexes have been characterized by elemental analyses, IR and electronic spectroscopies. The increased νC–N value in all the complexes is due to the mesomeric drift of electrons from the dithiocarbamate ligands to the metal atom. Single crystal X‐ray structure of [Ni(nmedtc)(1,3‐dppp)]ClO₄·H₂O is reported. In the present 1,3‐dppp chelate, the P–Ni–P angle is higher than that found in 1,2‐bis(diphenylphosphino)ethane‐nickel chelates and lower than 1,4‐bis(diphenylphosphino)butane‐nickel chelates, as a result of presence of the flexible propyl back bone connecting the two phosphorus atoms of the complex.     

New tetra- and pentacoordinate nickel(I) complexes

Summary The reduction of nickel(II) halides with NaBH₄ in ethanol has been studied in the presence of various tertiary phosphines and arsines. Complexes of the type XNiL₃ have been isolated in this way when X = Cl, Br, I and L = PPh₃, AsPh₃, no reaction being observed when L = PEt₃, PBu₃ and Ph₂P(CH₂)₂PPh₂.The reaction of XNiL₃ with CO gas at room temperature produces pentacoordinate carbonyl complexes XNi(CO)₂L₂ when L is triphenylphosphine. The lack of stability prevents the isolation of similar complexes when L is trip henylarsine.Structural data obtained by i.r. spectroscopy and susceptibility measurements as well as chemical behaviour of the new complexes are described.     

SYNTHESIS,CHARACTERIZATION AND ELECTROCHEMICAL STUDIES OF NICKEL(II) SELENOLATES

Abstract

The synthesis and characterization of the complexes [NiCl(SeAr)(DPPE)] (1) and [Ni(SeAr)₂(DPPE)] (2) (where Ar = C₆H₅ (a), 4-MeOC₆H₄ (b) or 4-EtOC₆H₄ (c), and DPPE = 1,2-bis(diphenylphosphino)-ethane) is reported. Characterization of the compounds was based on elemental analysis, molecular weight and conductivity measurements, IR, electronic, ¹H and ³¹P NMR spectra. Available evidence supports a square planar environment around Ni(II) in 1 and 2. Metathetical reaction between 1b and NaX (X = Br (d) or I (e)) in MeOH gives [NiX(SeAr)(DPPE)] (3). Electrochemical studies of 1 and 2 using cyclic voltammetry indicate an irreversible cathodic peak (ca ?0.56 to ?0.70 V) corresponding to reduction of nickel(II) to nickel (O).     

Nickel(II) N‐Benzyl‐N‐methyldithiocarbamato Complexes as Precursors for the Preparation of Graphite Oxidation Accelerators

The nickel(II) N‐benzyl‐N‐methyldithiocarbamato (BzMedtc) complexes [Ni(BzMedtc)(PPh₃)Cl] ( 1 ), [Ni(BzMedtc)(PPh₃)Br] ( 2 ), [Ni(BzMedtc)(PPh₃)I] ( 3 ), and [Ni(BzMedtc)(PPh₃)(NCS)] ( 4 ) were synthesized using the reaction of [Ni(BzMedtc)₂] and [NiX₂(PPh₃)₂] (X = Cl, Br, I and NCS). Subsequently, complex 1 was used for the preparation of [Ni(BzMedtc)(PPh₃)₂]ClO₄ ( 5 ), [Ni(BzMedtc)(PPh₃)₂]BPh₄ ( 6 ), and [Ni(BzMedtc)(PPh₃)₂]PF₆ ( 7 ). The obtained complexes 1 – 7 were characterized by elemental analysis, thermal analysis and spectroscopic methods (IR, UV/Vis, ³¹P{¹H} NMR). The results of the magnetochemical and molar conductivity measurements proved the complexes as diamagnetic non‐electrolytes ( 1 – 4 ) or 1:1 electrolytes ( 5 – 7 ). The molecular structures of 4 and 5· H₂O were determined by a single‐crystal X‐ray analysis. In all cases, the Ni^II atom is tetracoordinated in a distorted square‐planar arrangement with the S₂PX, and S₂P₂ donor set, respectively. The catalytic influence of selected complexes 1 , 3 , 5 , and 6 on graphite oxidation was studied. The results clearly indicated that the presence of the products of thermal degradation processes of the mentioned complexes has impact on the course of graphite oxidation. A decrease in the oxidation start temperatures by about 60–100 °C was observed in the cases of all the tested complexes in comparison with pure graphite.     

Nickel(II) hexamethyleneiminedithiocarbamate complexes with triphenylphosphine or tributylphosphine

A series of square-planar nickel(II) hexamethylenedithiocarbamate complexes with heterogeneous coordination spheres of composition [NiX(hmidtc)Y] · nCHCl₃ [X = Cl, Br, I or NCS; hmi = C₆H₁₂, dtc = S₂CN^–; Y = PPh₃ or PBu₃, n = 0,1] have been synthesized and characterized by elemental analyses, i.r. and u.v.–v.i.s. spectroscopy, magnetochemical and conductivity measurements, and by thermal analysis. X-ray structures of [NiCl(hmidtc)(PPh₃)] · CHCl₃ and [NiBr(hmidtc)(PPh₃)] · CHCl₃ have been determined.