Reactivity of [Ni(cod)2][Al(ORF)4] towards Small Molecules and Elements

To provide a better understanding of the recently published pure metalorganic Ni^I species, [Ni(cod)₂][Al(OR^F)₄] ( 1 ) [cod = 1,5‐cyclooctadiene, R^F = C(CF₃)₃], further characterizations were performed and analyzed. Thus, the solvation of 1 in THF was examined by EPR, surprisingly disclosing the initiation of a disproportionation reaction to [Ni^II(THF)₆][Al(OR^F)₄]₂ ( 3 ) and Ni⁰. Further studies concerning the ability of 1 to activate small molecules exhibit the formation of a remarkable [Ni₃S₂(cod)₃]²⁺ cluster ( 5 ) in an oxidation reaction with S₈, while EPR measurements of the resulting product in a reaction with oxygen indicate a possible coordination of O₂. Single crystal X‐ray structures as well as spectroscopic analyses of 3 and 5 are described.     

Tetracyanometallates with Complex Dien Cations: [Ni(dien)2][Ni(CN)4]·2H2O and [Ni(dien)2][Pd(CN)4]

The crystal structures of two square tetracyanocomplexes were determined. [Ni(dien)₂][Ni(CN)₄]·2H₂O (NDNCH) and [Ni‐(dien)₂][Pd(CN)₄] (NDPC) (dien = diethylene triamine) exhibit ionic structures consisting of mer‐[Ni(dien)₂]²⁺ cations and [Ni(CN)₄]^2‐ or [Pd(CN)₄]^2‐ anions, respectively. Moreover, the structure of NDNCH is completed by two water molecules of crystallisation. In both compounds hydrogen bonds contribute to the stabilisation of the structure. NDNCH dehydrates on air quickly yielding anhydrous [Ni(dien)₂][Ni(CN)₄] (NDNC). Its thermal decomposition proceeds in a complicated process followed by aerial oxidation of metallic nickel to NiO.     

Derivate des Flußspat-Typs: [Fe(NH3)6][TaF6]2 und [Ni(NH3)6][TaF6]2

Derivatives of the Fluorite Type: [Fe(NH₃)₆][TaF₆]₂ and [Ni(NH₃)₆][TaF₆]₂ Light blue single crystals of [Fe(NH₃)₆][TaF₆]₂ and [Ni(NH₃)₆][TaF₆]₂ are obtained from 36 : 1 : 6 molar mixtures of (NH₄)F, iron/nickel and tantalum powders, respectively, in sealed Monel metal ampoules at 400 °C. They both crystallize isotypic with [Co(NH₃)₆][PF₆]₂ (cubic, Fm-3m, Z = 4, a = 1259.0(2)/1260.4(2) pm) in a structure that can be derived from the basic fluorite-type of structure according to [Ca][F]₂≡[Fe(NH₃)₆][TaF₆]₂, for example.     

[Ni(iPr2Im)2Br2]: A Convenient Entry into NHC Nickel ­Chemistry

The reaction of the NHC iPr₂Im [NHC=N‐heterocyclic carbene, iPr₂Im = 1, 3‐bis(isopropyl)imidazolin‐2‐ylidene] with freshly prepared NiBr₂ in thf or dme results in the formation of the air stable nickel(II) complex trans‐[Ni(iPr₂Im)₂Br₂] ( 2 ). Complex 2 was structurally characterized. Thermal analysis (DTA/TG) reveals a very high decomposition temperature of 298 °C. Reduction of 2 with sodium or C₈K in the presence of the olefins COD (cyclooctadiene) or COE (cyclooctene) affords the highly reactive compounds [Ni₂(iPr₂Im)₄(COD)] ( 1 ) and [Ni(iPr₂Im)₂(COE)] ( 4 ). Alkylation of 2 with organolithiums leads to the formation of trans‐[Ni(iPr₂Im)₂(R)₂] [R = Me ( 5 ), CH₂SiMe₃ ( 6 )], whereas the reaction of 2 with LiCp* [Cp* = (η⁵‐C₅(CH₃)₅)] at 80 °C causes the loss of one NHC ligand and affords [(η⁵‐C₅(CH₃)₅)Ni(iPr₂Im)Br] ( 7 ).     

Umsetzung von C(NMe2)4 mit Ni(CO)4 – Synthesen und Strukturen von [C(NMe2)3][(CO)3NiC(O)NMe2], [C(NMe2)3]2[Ni5(CO)12] und [C(NMe2)3]3[Ni6(CO)12][O2CNMe2]

Reaction of C(NMe₂)₄ with Ni(CO)₄ – Syntheses and Structures of [C(NMe₂)₃][(CO)₃NiC(O)NMe₂], [C(NMe₂)₃]₂[Ni₅(CO)₁₂], and [C(NMe₂)₃]₃[Ni₆(CO)₁₂][O₂CNMe₂] The reaction of C(NMe₂)₄ with Ni(CO)₄ in THF produces the carbamoyl complex [C(NMe₂)₃][(CO)₃NiC(O)NMe₂] ( 1 ); side products are the purple cluster compound [C(NMe₂)₃]₂[Ni₅(CO)₁₂] · THF ( 2 · THF) and the red cocristallization product [C(NMe₂)₃]₃[Ni₆(CO)₁₂][O₂CNMe₂] ( 3 ). All compounds were studied by X‐ray diffraction analyses. The cations of 3 are all disordered but not those of 1 and 2 . The unit cell of 1 contains two crystallographically independent anions (I and II) which differ in the dihedral angle between the plane of the carbamoyl ligand and the plane defined by the atoms C_Carbamoyl–Ni–CO amounting 0° in the anion I and 18° in the anion II.     

Synthesen und Kristallstrukturen der chalkogenidoverbrückten Nickelclusterverbindungen [Ni5Se4Cl2(PPhEt2)6], [Ni12Se12(PnPr3)6] und [Ni18S18(PiPr3)6]

Syntheses and Crystal Structures of Chalcogenido‐bridged Nickel Cluster Compounds [Ni₅Se₄Cl₂(PPhEt₂)₆], [Ni₁₂Se₁₂(PⁿPr₃)₆], and [Ni₁₈S₁₈(PⁱPr₃)₆] The reaction of (R)ESiMe₃ (R = SiMe₃, Mes = C₉H₁₁; E = S, Se) with [NiCl₂(PPhEt₂)₂] and [NiCl₂(PR₃)₂] (R = ⁿPr, ⁱPr) gives new chalcogenido‐bridged nickel cluster compounds [Ni₅Se₄Cl₂(PPhEt₂)₆]·2THF ( 1 ), [Ni₁₂Se₁₂(PⁿPr₃)₆]·2THF ( 2 ), and [Ni₁₈S₁₈(PⁱPr₃)₆]·2THF ( 3 ). The structures of these compounds were determined by single crystal X‐ray structural analyses.     

Synthesis and crystal structure of Cu(I) and Ni(II) complexes of 1,1-diethyl-3-(4-fluorobenzoyl)-thiourea

The reaction of 1,1-diethyl-3-(4-fluorobenzoyl)-thiourea (HL) with CuCl₂ ·?2H₂O and NiCl₂ ·?6H₂O give two complexes, Cu(HL)₃Cl (1) and NiL₂ (2). The crystal structures of these products were determined by single crystal X-ray diffraction. In 1, three HL molecules are unidentate, coordinating through the sulfur, and the copper is tetrahedral with three S and one Cl. In 2, two HL molecules are O and S donor bidentate and coordinate as anionic species with loss of the proton from the acyl-substituted nitrogen; the nickel is square-planar.     

Divergent Reactivity of a Dinuclear (NHC)Nickel(I) Catalyst versus Nickel(0) Enables Chemoselective Trifluoromethylselenolation

We herein showcase the ability of NHC‐coordinated dinuclear Ni^I–Ni^I complexes to override fundamental reactivity limits of mononuclear (NHC)Ni⁰ catalysts in cross‐couplings. This is demonstrated with the development of a chemoselective trifluoromethylselenolation of aryl iodides catalyzed by a Ni^I dimer. A novel SeCF₃‐bridged Ni^I dimer was isolated and shown to selectively react with Ar−I bonds. Our computational and experimental reactivity data suggest dinuclear Ni^I catalysis to be operative. The corresponding Ni⁰ species, on the other hand, suffers from preferred reaction with the product, ArSeCF₃, over productive cross‐coupling and is hence inactive.     

配合物[2-NaPhthMePyNH_2]_2[Ni(mnt)_2]的合成及表征

合成了马来二氰基二硫烯镍(Ⅱ)配合物,[2-Na Phth Me Py NH2]2[Ni(mnt)2]([2-Na Phth Me Py NH2]+为1-(2'-萘苄基)-2-氨基吡啶鎓离子),并用元素分析,UV,IR,单晶X-射线衍射表征了其组成和结构。结果表明,配合物系单斜晶系,空间群P21/c,a=13.335(2),b=7.9458(12),c=17.480(3),α=90°,β=97.646(2)°,γ=90°,V=1835.7(5),Z=2。     

Nickel(IV) dithiocarbamato complexes of the [Ni(ndtc)3]X type: X-ray structure of [Ni(hmidtc)3][FeCl4]

A series of fourteen octahedral nickel(IV) dithiocarbamato complexes of the general formula [Ni(ndtc)₃]X·yH₂O {ndtc stands for the appropriate dithiocarbamate anion, X stands for ClO₄⁻ (1-8; y = 0) or [FeCl₄]⁻ (9-14; y = 0 for 9-12, 1 for 13 and 0.5 for 14} was prepared by the oxidation of the corresponding nickel(II) complexes, i.e. [Ni(ndtc)₂], with NOClO₄ or FeCl₃. The complexes, involving a high-valent Ni^IVS₆ core, were characterized by elemental analysis (C, H, N, Cl and Ni), UV-Vis and FTIR spectroscopy, thermal analysis and magnetochemical and conductivity measurements. The X-ray structure of [Ni(hmidtc)₃][FeCl₄] (9) was determined {it consists of covalently discrete complex [Ni(hmidtc)₃]⁺ cations and [FeCl₄]⁻ anions} and this revealed slightly distorted octahedral and tetrahedral geometries within the complex cations, and anions, respectively. The Ni(IV) atom is six-coordinated by three bidentate S-donor hexamethyleneiminedithiocarbamate anions (hmidtc), with Ni-S bond lengths ranging from 2.2597(5) to 2.2652(5) Å, while the shortest Ni···Cl and Ni···Fe distances equal 4.1043(12), and 6.2862(6) Å, respectively. Moreover, the formal oxidation state of iron in [FeCl₄]⁻ as well as the coordination geometry in its vicinity was also proved by ⁵⁷Fe Mössbauer spectroscopy in the case of 9.     

Ein neuer Aluminium/Nickel/Oxo‐Cluster: [Ni(acac)OAl(OtBu)2]4

A New Aluminum/Nickel/Oxo‐Cluster: [Ni(acac)OAl(OtBu)₂]₄ When bis(tert‐butoxy)alane (tBu‐O)₂AlH is allowed to react with nickeldiacetylacetonate at elevated temperature a new nickel/aluminum/oxo cluster [Ni(acac)OAl(OtBu)₂]₄ is formed together with aluminum acetylacetonate Al(acac)₃ and some other products. The metal/oxo cluster is isolated by crystallization and structurally fully characterized by X‐ray diffraction analysis. The molecule [Ni(acac)OAl(OtBu)₂]₄ contains an eight membered Al₄O₄ cycle, to which eight mutually edge sharing NiO₂Al cycles are fused. The overall point symmetry of the metal/oxo cluster is almost S₄. While the aluminum atoms are tetrahedrally surrounded by oxygen ligands (mean distances Al‐O in‐between 1, 730(6) and 1, 789(6) Å)), the nickel atoms are in a square pyramidal coordination sphere of oxygen atoms (Ni‐O_axial = 1.938(6) Å, Ni‐O_basal = 2.056(9) Å; all polyhedra are distorted). The nickel atoms have a d⁸ high spin electron configuration (μ_eff = 3.32 B.M.).     

Synthese und Strukturuntersuchungen von Iodocupraten(I). XV Iodocuprate(I) mit solvatisierten Kationen: [Li(CH3CN)4][Cu2I3] und [Mg{(CH3)2CO}6][Cu2I4]

Synthesis and Structure Investigations of Iodocuprates(I). XV Iodocuprate(I) with Solvated Cations: [Li(CH₃CN)₄] [Cu₂I₃] and [Mg{(CH₃)₂CO}₆][Cu₂I₄] [Li(CH₃CN)₄][Cu₂I₃] 1 and [Mg((CH₃)₂CO)₆][Cu₂I₄] 2 were prepared by reactions of CuI with LiI in acetonitrile and of CuI with MgI₂ in acetone. 1 crystallizes orthorhombic, Pnma, a = 552.7(2), b = 1258.8(8), c = 2516(1) pm, z = 4. [Li(CH₃CN)₄]⁺ cations are located between rod packings of CuI₄ tetrahedra double chains [(CuI_2/2I_2/4)₂]^? parallel to the axis. Short intermolecular anion/cation contacts were observed. The crystal structure of 2 (monoclinic, P2₁/n, a = 1840(2), b = 1059.2(2), c = 1879(2)pm, β = 112.94(4)°, z = 4) is built up by [Mg((CH₃)₂CO)₆]²⁺ cations forming a simple hexagonal sphere packing. The binuclear anions [Cu₂I₄]^2? occupy holes in the trigonal prismatic channels formed by the cations.     

Darstellung und Kristallstrukturen von Ag[N(CN)2](PPh3)2, Cu[N(CN)2](PPh3)2 und Ag[N(CN)2](PPh3)3

Preparation and Crystal Structures of Ag[N(CN)₂](PPh₃)₂, Cu[N(CN)₂](PPh₃)₂, and Ag[N(CN)₂](PPh₃)₃ The coordination compounds Ag[N(CN)₂](PPh₃)₂ ( 1 ), Cu[N(CN)₂](PPh₃)₂ ( 2 ), and Ag[N(CN)₂](PPh₃)₃ ( 3 ) are obtained by the reaction of AgN(CN)₂ or CuN(CN)₂ with triphenylphosphane in CH₂Cl₂. X‐ray structure determinations were performed on single crystals of 1 , 2 , and 3 · C₆H₅Cl. The three compounds crystallize monoclinic in the space group P2₁/n with the following unit cell parameters. 1 : a = 1216.07(9), b = 1299.5(2), c = 2148.4(3) pm, β = 99.689(13)°, Z = 4; 2 : a = 1369.22(10), b = 1257.29(5), c = 1888.04(15) pm, β = 94.395(7)°, Z = 4; 3 · C₆H₅Cl: a = 1276.6(4), b = 1971.7(3), c = 2141.3(5) pm, β = 98.50(3)°, Z = 4. In all structures the metal atoms have a distorted tetrahedral coordination. The crystal structure of 3 · C₆H₅Cl shows monomeric molecular units with terminal coordinated dicyanamide. The crystal structure of 1 is built up by dinuclear units, which are bridged by dicyanamide ligands. However, the crystal structure of 2 corresponds to a onedimensional coordination polymer, bridged by dicyanamide anions.     

Phosphaniminato‐ und Phosphanimin‐Komplexe von Nickel(II). Die Kristallstrukturen von [Ni(O3SCF3)(NPMe3)]4, [Ni4Br5{NP(NMe2)3}3], [NiBr2{HNP(NMe2)3}2] und [Ni(PMePh2)4]

Phosphoraneiminato‐ and Phosphaneimine Complexes of Nickel(II). Crystal Structures of [Ni(O₃SCF₃)(NPMe₃)]₄, [Ni₄Br₅{NP(NMe₂)₃}₃], [NiBr₂{HNP(NMe₂)₃}₂], and [Ni(PMePh₂)₄] Black‐violet single crystals of [Ni(O₃SCF₃)(NPMe₃)]₄ ( 1 ) have been prepared from [NiBr(NPMe₃)]₄ and copper(I)triflate by metathesis reaction. The nickel atoms are associated via μ₃‐N bridges of the (NPMe₃^–) groups to form a heterocubane. The triflate ions are bonded to the Ni atoms in a chelate fashion. Blue single crystals of [Ni₄Br₅{NP(NMe₂)₃}₃] ( 2 ) are obtained by the reaction of NiBr₂ with Me₃SiNP(NMe₂)₃ in boiling toluene in the presence of sodium fluoride. The Ni atoms in 2 are associated with three μ₃‐bridged nitrogen atoms of the (NP(NMe₂)₃^–) groups as well as by a μ₃‐Br atom to give a distorted heterocubane. Deep blue single crystals of the phosphaneimine complex [NiBr₂{HNP(NMe₂)₃}₂] ( 3 ) are formed from Me₃SiNP(NMe₂)₃ and NiBr₂ in boiling dichloromethane. In 3 the Ni atom is tetrahedrally coordinated by the bromine atoms and by the nitrogen atoms of the phosphane imine molecules. Pale red crystals of [Ni(PMePh₂)₄] ( 4 ) have been obtained by the reaction of [NiBr(NPMe₃)]₄ with lithium phenylacetilyde in the presence of PMePh₂. In 4 the Ni atom is distorted tetrahedrally coordinated by the phosphorus atoms of the phosphane molecules with Ni–P distances of 219.9 pm in average. 1 – 4 have been characterized by crystallographic X‐ray analyses. 1 : Space group P2₁/n, Z = 4, lattice dimensions at 193 K: a = 1566.7(2); b = 1479.9(1); c = 1960.6(2) pm; β = 105.908(9)°; R = 0.0443. 2 · 3 CH₂Cl₂: Space group P2₁/c, Z = 4, lattice dimensions at 293 K: a = 1226.0(3); b = 1614.0(3); c = 2406.0(5) pm; β = 92.34(3)°; R = 0.0703. 3 : Space group C2/c, Z = 4, latttice dimensions at 203 K: a = 1840.7(1); b = 810.1(1); c = 1607.2(2) pm; β = 94.74(1)°, R = 0.0340. 4 : Space group P1, Z = 2, lattice dimensions at 223 K: a = 1053.1(2); b = 1315.0(3); c = 1674.5(3) pm; α = 81.55(1)°; β = 79.15(2)°; γ = 84.91(2)°; R = 0.0497.     

Facile Synthesis and Molecular Structure of [Ni(PPh2NHPh)4]

NiCl₂ · 6 H₂O readily reacts with PPh₂NHPh in the presence of zinc dust to yield the homoleptic nickel(0) tetrakis‐phosphine complex [Ni(PPh₂NHPh)₄] ( 1 ). 1 crystallises triclinic P1 (no. 2), with a = 14.656(1), b = 17.124(2), c = 17.424(1) Å, α = 95.998(1), β = 111.845(1), γ = 111.402(1)°, V = 3630.04(5) ų, Z = 2, R values [I > 2σ(I)]: R1 = 0.0554, all data: wR2 = 0.1720. The nickel atom is coordinated in a distorted tetrahedral fashion by four phosphorus atoms, resembling a compressed tetrahedron along one of the non‐crystallographic S₄ axes.     

Die Kristallstrukturen von trans‐[NiBr2(Pyridin)4] und [Ni(HNPEt3)4]I2

Crystal Structures of trans ‐[NiBr₂(pyridine)₄] and [Ni(HNPEt₃)₄]I₂ Turquoise single crystals of trans‐[NiBr₂(pyridine)₄] have been obtained by the reaction of excess pyridine with nickel(II) bromide/diacetonealcohol. According to the crystal structure determination the nickel atom is octahedrally coordinated by the two bromine atoms in trans‐position and by the nitrogen atoms of the pyridine molecules. Space group Pna2₁, Z = 4, lattice dimensions at 20 °C: a = 1592.9(2), b = 943.8(1), c = 1413.0(2) pm, R₁ = 0.0492. Dark blue single crystals of the phosphoraneimine complex [Ni(HNPEt₃)₄]I₂ have been obtained from NiI₂/H₂O with excess Me₃SiNPEt₃ and subsequent recrystallization from acetonitrile. According to the crystal structure determination the nickel atom is tetrahedrally coordinated by the nitrogen atoms of the HNPEt₃ molecules. The iodide ions are connected via N–H…I contacts with the cation to form an ion triple. Space group P2₁/c, Z = 4, lattice dimensions at –80 °C: a = 1934.9(2), b = 1078.3(1), c = 1966.3(2) pm, β = 111.040(8)°; R₁ = 0.043.     

Reactivity of fac-[PPN][Fe(CO)3(TePh)3]: Structure of Fe2(μTePh)2(NO)4

Addition of NOBF₄ to fac-[PPN][Fe(CO)₃(TePh)₃] in THF at ambient temperature results in formation of Fe₂(μ-TePh)₂(NO)_4l Fe₂(?TePh)₂(CO)₆ and organic products. Methylation of fac-[PPN][Fe(CO)₃- (TePh)₃] by Mel or [Me₃O][BF₄] leads to the known dimer Fe₂(μ.-TePh)₂(CO)₆ and organic products. Fe₂(μ-TePh)₂(NO)₄ crystallizes in the orthorhombic space group P bca, with a = 12.701(5) Å, b = 6.7935(16) Å, c = 21.299(9) Å, V = 1837.8(11) ų, and Z = 4. The core geometry of Fe₂(μ-TePh)₂(NO)₄ is best described as a Fe₂Te₂ planar rhombus with Te-Fe-Te bond angle 112.09(4)°. A Fe-Fe bond (length 2.827(2) Å) is proposed for Fe₂(μ-TePh)₂(NO)₄ on the basis of the 18-electron rule. The iron atom adopts a distorted tetrahedral geometry with acute bridge Fe-Te-Fe angles 67.91(3)°, and bridging Fe-Te bond of length 2.53(1) Å.     

Nickel and copper complexes of cyclopropyltetrazole: crystal structures of [Ni(C3tz)6](BF4)2 and [Cu(C3tz)6](BF4)2

Cyclopropyltetrazole (C₃tz) and its nickel(II) and copper(II) complexes [M(C₃tz)₆](BF₄)₂] were isolated and characterized by elemental analyses, electronic spectroscopy, molar conductances, magnetic susceptibilities and single-crystal X-ray analyses.     

Zur Reaktion von NiCl2 mit PhP(SiMe3)2 Die Kristallstruktur von [Ni12Cl2(PPh)2(P2Ph2)4(PHPh)8]

Reaction of NiCl₂ with PhP(SiMe₃)₂, The Crystal Structure of [Ni₁₂Cl₂(PPh)₂(P₂Ph₂)₄(PHPh)₈] [Ni₁₂Cl₂(PPh)₂(P₂Ph₂)₄(PHPh)₈] ( 1 ) has been prepared by the reaction of NiCl₂ with PhP(SiMe₃)₂. The structure has been characterized by X-ray crystal structure analysis. 1 contains a Ni₁₂-cluster with m?₄-PPh- and m?₆-P₂Ph₂- as bridging ligands. The terminal PHPh- and Cl-ligands are bound to Ni-atoms. The Ni₁₂-cluster can be described as an Ni₈-cube, in which four edges are bridged by Ni-atoms.