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).     

Synthesis and spectroscopic studies of nickel(II) chalcogenolates derived from 1,2-diarylchalcogenolato-o-xylene

Nickel(II) chalcogenolate complexes [Ni(L-L)₂(dppe) Cl₂] (1, 2) have been prepared in high yields by reacting 1,2-diarylchalcogenolato-o-xylene, o-C₆H₄(CH₂EAr)₂ (E = Se or Te; Ar = Ph, C₆H₄OMe-4 and C₆H₄OEt-4), generated in situ, with Ni(dppe)Cl₂ [dppe = 1,2-bis(diphenylphosphino)ethane] in benzene. The structures were established by elemental analyses, molar conductance, i.r. and Raman, electronic ¹H- and ³¹P-n.m.r. and mass spectral data. The analytical and spectroscopic data are consistent with an octahedral geometry around nickel in (1) and (2). The ³¹P-n.m.r. spectra indicate their cis configuration in solution. This revised version was published online in June 2006 with corrections to the Cover Date.     

Stoichiometric and Catalytic Aryl−Cl Activation and Borylation using NHC-stabilized Nickel(0) Complexes

NHC-nickel (NHC=N-heterocyclic carbene) complexes are efficient catalysts for the C−Cl bond borylation of aryl chlorides using NaOAc as a base and B₂pin₂ (pin=pinacolato) as the boron source. The catalysts [Ni₂(ICy)₄(μ-(η²:η²)-COD)] ( 1 , ICy=1,3-dicyclohexylimidazolin-2-ylidene; COD=1,5-cyclooctadiene), [Ni(ICy)₂(η²-C₂H₄)] ( 2 ), and [Ni(ICy)₂(η²-COE)] ( 3 , COE=cyclooctene) compare well with other nickel catalysts reported previously for aryl-chloride borylation with the advantage that no further ligands had to be added to the reaction. Borylation also proceeded with B₂neop₂ (neop=neopentylglycolato) as the boron source. Stoichiometric oxidative addition of different aryl chlorides to complex 1 was highly selective affording trans-[Ni(ICy)₂(Cl)(Ar)] (Ar=4-(F₃C)C₆H₄, 11 ; 4-(MeO)C₆H₄, 12 ; C₆H₅, 13 ; 3,5-F₂C₆H₃, 14 ).     

Synthesis and characterization of heterobimetallic mixed-ligand complexes containing Zr(μ-OPri)2Al bridging units

Interesting varieties of heterobimetallic mixed-ligand complexes [Zr{M(OPrⁱ) _n }₂ (L)] (where M = Al, n = 4, L = OC₆H₄CH = NCH₂CH₂O (1); M = Nb, n = 6, L = OC₆H₄CH = NCH₂CH₂O (2); M = Al, n = 4, L = OC₁₀H₆CH = NCH₂CH₂O (3); M = Nb, n = 6, L = OC₁₀H₆CH = NCH₂CH₂O (4)), [Zr{Al(OPrⁱ)₄}₂Cl(OAr)] (where Ar = C₆H₃Me₂-2,5 (5); Ar = C₆H₂Me-4-Bu₂-2,6 (6), [Zr{Al(OPrⁱ)₄}₂(OAr)₂] (where Ar = C₆H₃Me₂-2,5 (7); Ar = C₆H₂Me-4-Bu₂-2,6 (8), [Zr{Al(OPrⁱ)₄}₃(OAr)] (where Ar = C₆H₃Me₂-2,5 (9); Ar = C₆H₃Me₂-2,6 (10), [ZrAl(OPrⁱ)_7-n (ON=CMe₂) _n ] (where n = 4 (11); n = 7 (12), [ZrAl₂(OPrⁱ)_10-n (ON=CMe₂) _n ] (where n = 4 (13); n = 6 (14); n = 10 (15) and [Zr{Al(OPrⁱ)₄}₂{ON=CMe(R)} _n Cl_2–n] [where n = 1, R = Me (16); n = 2, R = Me (17); n = 1, R = Et (18); n = 2, R = Et (19)] have been prepared either by the salt elimination method or by alkoxide-ligand exchange. All of these heterobimetallic complexes have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (I.r., ¹H-, and ²⁷Al- n.m.r.) studies.     

Vinyl polymerization of norbornene by mono‐ and trinuclear nickel complexes with indanimine ligands

A series of new indanimine ligands [ArN?CC₂H₃(CH₃)C₆H₂(R)OH] (Ar = Ph, R = Me ( 1 ), R = H ( 2 ), and R = Cl ( 3 ); Ar = 2,6‐i‐Pr₂C₆H₃, R = Me ( 4 ), R = H ( 5 ), and R = Cl ( 6 )) were synthesized and characterized. Reaction of indanimines with Ni(OAc)₂·4H₂O results in the formation of the trinuclear hexa(indaniminato)tri (nickel(II)) complexes Ni₃[ArN = CC₂H₃(CH₃)C₆H₂(R)O]₆ (Ar = Ph, R = Me ( 7 ), R = H ( 8 ), and R = Cl ( 9 )) and the mononuclear bis(indaniminato)nickel (II) complexes Ni[ArN?CC₂H₃(CH₃)C₆H₂(R)O]₂ (Ar = 2,6‐i‐Pr₂C₆H₃, R = Me ( 10 ), R = H ( 11 ), and R = Cl ( 12 )). All nickel complexes were characterized by their IR, NMR spectra, and elemental analyses. In addition, X‐ray structure analyses were performed for complexes 7 , 10 , 11 , and 12 . After being activated with methylaluminoxane (MAO), these nickel(II) complexes can polymerize norbornene to produce addition‐type polynorbornene (PNB) with high molecular weight M_v (10⁶ g mol^?1), highly catalytic activities up to 2.18 × 10⁷ gPNB mol^?1 Ni h^?1. Catalytic activities and the molecular weight of PNB have been investigated for various reaction conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 489–500, 2008     

Micron‐granula polyolefin with self‐immobilized nickel and iron diimine catalysts bearing one or two allyl groups

Self‐immobilized nickel and iron diimine catalysts bearing one or two allyl groups of [ArN?C]₂(C₁₀H₆)NiBr₂ [Ar = 4‐allyl‐2,6‐(i‐Pr)₂C₆H₂] ( 1 ), [ArN?C(Me)][Ar′N? C(Me)]C₅H₃NFeCl₂ [Ar = Ar′ = 4‐allyl‐2,6‐(i‐Pr)₂C₆H₃, Ar = 2,6‐(i‐Pr)₂C₆H₃, and Ar′ = 4‐allyl‐2,6‐(i‐Pr)₂C₆H₃] were synthesized and characterized. All three catalysts were investigated for olefin polymerization. As a result, these catalysts not only showed high activities as the catalyst free from the allyl group, such as [ArN?C]₂C₁₀H₆NiBr₂ (Ar = 2,6‐(i‐Pr)₂C₆H₂)], but also greatly improved the morphology of polymer particles to afford micron‐granula polyolefin. The self‐immobilization of catalysts, the formation mechanism of microspherical polymer, and the influence on the size of the particles are discussed. The molecular structure of self‐immobilized nickel catalyst 1 was also characterized by crystallographic analysis. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1018–1024, 2004     

Phosphine-Stabilized Pnictinidenes

The reaction of the intramolecular germylene-phosphine Lewis pair (o-PPh₂)C₆H₄GeAr* ( 1 ) with Group 15 element trichlorides ECl₃ (E=P, As, Sb) was investigated. After oxidative addition, the resulting compounds (o-PPh₂)C₆H₄(Ar*)Ge(Cl)ECl₂ ( 2 : E=P, 3 : E=As, 4 : E=Sb) were reduced by using sodium metal or LiHBEt₃. The molecular structures of the phosphine-stabilized phosphinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)P ( 5 ), arsinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)As ( 6 ) and stibinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)Sb ( 7 ) are presented; they feature a two-coordinate low-valent Group 15 element. After chloride abstraction, a cyclic germaphosphene [(o-PPh₂)C₆H₄(Ar*)GeP] [B(C₆H₃(CF₃)₂)₄] ( 8 ) was isolated. The ³¹P NMR data of the germaphosphene were compared with literature examples and analyzed by quantum chemical calculations. The phosphinidene was treated with [iBu₂AlH]₂, and the product of an Al−H addition to the low-valent phosphorus atom (o-PPh₂)C₆H₄(Ar*)Ge(H)P(H)Al(C₄H₉)₂ ( 9 ) was characterized.     

Synthesis and characterization of novel neutral nickel complexes bearing fluorinated salicylaldiminato ligands and their catalytic behavior for vinylic polymerization of norbornene

A series of salicylaldimine‐based neutral Ni(II) complexes (3a–j) [ArN = CH(C₆H₄O)]Ni(PPh₃)Ph [3a, Ar = C₆H₅; 3b, Ar = C₆H₄F(o); 3c, Ar = C₆H₄F(m); 3d, Ar = C₆H₄F(p); 3e, Ar = C₆H₃F₂(2,4); 3f, Ar = C₆H₃F₂(2,5); 3g, Ar = C₆H₃F₂(2,6); 3h, Ar = C₆H₃F₂(3,5); 3i, Ar = C₆H₂F₃(3,4,5); 3j, Ar = C₆F₅] have been synthesized in good yield, and the structures of complexes 3a and 3i have been confirmed by X‐ray crystallographic analysis. Using modified methylaluminoxane as a cocatalyst, these neutral Ni(II) complexes exhibited high catalytic activities for the vinylic polymerization of norbornene. It was observed that the strong electron‐withdrawing effect of the fluorinated salicylaldiminato ligand was able to significantly increase the catalyst activity for vinylic polymerization of norbornenes. In addition, catalyst activity, polymer yield and polymer molecular weight can also be controlled over a wide range by the variation of reaction parameters such as Al:Ni ratio, norbornene:catalyst ratio, monomer concentration, polymerization temperature and time. Copyright © 2008 John Wiley & Sons, Ltd.     

Organonickel(II) Complexes with Anionic N-Donor Ligands. Hydration of coordinated nitriles at a nickel(II) site

The hydroxo complex (Bu₄N)₂[Ni₂(C₆F₅)₄(μ-OH)₂]reacts with 2,3,4,5,6-pentafluoro benzenamine (C₆F₅-NH₂), 1,3-diaryltriaz-1-enes (ArNH? N=N? Ar, Ar = Ph, 4-MeC₆H₄, 4-MeOC₆H₄), 7-aza-1H-indole (= 1H-pyrrolo[2.3-b]pyridine; Hazind), N-phenylpyridin-2-amine(pyNHPh), and N-phenylpyridine-2-carboxamide (py-CONHPh) at room temperature in acetone to give the binuclear complexes (Bu₄N)₂[Ni₂(C₆F₅)₄(μ-C₆F₅NH)₂] ( 1 ) and (Bu₄N)₂[{Ni(C₆F₅)₂} 2(μ-OH)(μ-azind)] ( 2 ) and the mononuclear complexes Bu₄N[Ni(C₆F₅)2(ArN₃Ar)] ( 3 – 5 ), Bu₄N[Ni(C₆F₅)₂(pyNPh)] ( 6 ), and Bu₄N[Ni(C₆F₅)₂(pyCONPh)] ( 7 ). The hydroxo.complex (Bu₄N)₂[{Ni(C₆F₅)2-(μ-OH)}₂] promotes the nucleophilic addition of water to pyridine-2-carbonitrile, 2-aminoacetonitrile, and 2-(dimethylamino)acetonitrile, and complexes 8 – 10 containing pyridine-2-carboxamidato, 2-aminoacetamidato and 2-(dimethylamino)acetamidato ligands are formed. Analytical (C, H, N) and spectroscopic (IR, ¹H and ¹⁹F-NMR, and FAB-MS) data were used for structural assignments. A single-crystal X-ray diffraction study of (Bu₄N)₂[{Ni(C₆F₅)₂}₂(μ-OH)(μ-azind)] ( 2 ) established the binuclear nature of the anion; the two Ni-atoms are bridged by an OH group and a 7-aza-7H-indol-7-yl group, but the central Ni? O? Ni? N? C? N ring is not planar, the dihedral angle between the Ni? O? Ni and Ni? N? C? N? Ni planes being 84.4°.     

Reactions of Organic Azides with Half‐sandwich Complexes of Iridium: Preparation of Mono‐ and Bis(imine) Derivatives

Imine complexes [IrCl(η⁵‐C₅Me₅){κ¹‐NH=C(H)Ar}{P(OR)₃}]BPh₄ ( 1 , 2 ) (Ar = C₆H₅, 4‐CH₃C₆H₄; R = Me, Et) were prepared by allowing chloro complexes [IrCl₂(η⁵‐C₅Me₅){P(OR)₃}] to react with benzyl azides ArCH₂N₃. Bis(imine) complexes [Ir(η⁵‐C₅Me₅){κ¹‐NH=C(H)Ar}₂{P(OR)₃}](BPh₄)₂ ( 3 , 4 ) were also prepared by reacting [IrCl₂(η⁵‐C₅Me₅){P(OR)₃}] first with AgOTf and then with benzyl azide. Depending on the experimental conditions, treatment of the dinuclear complex [IrCl₂(η⁵‐C₅Me₅)]₂ with benzyl azide yielded mono‐ [IrCl₂(η⁵‐C₅Me₅){κ¹‐NH=C(H)Ar}] ( 5 ) and bis‐[IrCl(η⁵‐C₅Me₅){κ¹‐NH=C(H)Ar}₂]BPh₄ ( 6 ) imine derivatives. In contrast, treatment of chloro complexes [IrCl₂(η⁵‐C₅Me₅){P(OR)₃}] with phenyl azide C₆H₅N₃ gave amine derivatives [IrCl(η⁵‐C₅Me₅)(C₆H₅NH₂){P(OR)₃}]BPh₄ ( 7 , 8 ). The complexes were characterized spectroscopically (IR, NMR) and by X‐ray crystal structure determination of [IrCl(η⁵‐C₅Me₅){κ¹‐NH=C(H)C₆H₄‐4‐CH₃}{P(OEt)₃}]BPh₄ ( 2b ).     

Synthese und Charakterisierung von Aquapentachloroplatinaten(IV) – Struktur von [K(18-Krone-6)][PtCl5(H2O)]

Synthesis and Characterization of Aquapentachloroplatinates(IV) – Structure of [K(18-crown-6)][PtCl₅(H₂O)] The crown ether complex of the aquapentachloroplatinic acid of the composition [H₁₃O₆][PtCl₅(H₄O₂)] · 2(18-cr-6) ( 2 ) reacts with K₂CO₃ and [NⁿBu₄]OH in aqueous solution to give [K(18-cr-6)][PtCl₅(H₂O)] ( 5 a ) and [NⁿBu₄][PtCl₅(H₂O)] · ¹/₂ (18-cr-6) · H₂O ( 5 b ), respectively. Both compounds were characterized by microanalysis, vibrational (IR, Raman) and NMR (¹H, ¹³C, ¹⁹⁵Pt) spectroscopy. The X-ray structure analysis of 5 a (orthorhombic, pnma; a = 16,550(4), b = 18,044(3), c = 7,415(1) Å; Z = 4; R1 = 0,0183; wR2 = 0,0414) reveals that the crystal is threaded by chains built up of [PtCl₅(H₂O)]^? and [K(18-cr-6)]⁺ units. There are tight K …? Cl contacts (d(K? Cl1)) = 3,0881(9) Å and O_W? H? O_cr hydrogen bridges (d(O1 …? O2) = 2,806(3) Å) between these units. The coordination polyhedron [PtCl₅O] has approximately C_4v symmetry.     

Synthesis of 2‐(N‐arylimino)pyrrolide nickel complexes and polymerization of methyl methacrylate

The synthesis, characterization and methyl methacrylate polymerization behaviors of 2‐(N‐arylimino)pyrrolide nickel complexes are described. The nickel complex [NN]₂Ni ( 1 , [NN] = [2‐C(H)NAr‐5‐tBu‐C₄H₂N]^?, Ar = 2,6‐iPr₂C₆H₃) was prepared in good yield by the reaction of [NN]Li with trans‐[Ni(Cl)(Ph)(PPh₃)₂] in THF. Reaction of [NN]Li with NiBr₂(DME) yielded the nickel bromide [NN]Ni(Br)[NNH] ( 2 ). Complexes 1 and 2 were characterized by ¹H NMR and IR spectroscopy and elemental analysis, and by X‐ray single crystal analysis. Both complexes, upon activation with methylaluminoxane, are highly active for the polymerization of methyl methacrylate to give high molecular weight polymethylmethacrylate with narrow molecular distributions. Copyright © 2009 John Wiley & Sons, Ltd.     

Square Planar Nickel（II） Complexes with Halogenated o-Diiminobenzosemiquinonato Ligation： Synthesis,Characterization, and Redox Property

Seven square planar bis（o-diiminobenzosemiquinonato）nickel（II） complexes, [Ni（o-C6H4（NH）（NAr））2] （Ar= Mes, 1; p-F-C6H4, 2; p-CI-C6H4, 3）, [Ni（o-4,5-F2-C6H2（NH）（NPh））2] （4）, and [Ni（o-4,5-CIz-C6H2（NH）（NAr））2] （Ar =Ph, 5; 2,6-F2-C6H3, 6; 2,6-C12-C6H3, 7）, have been synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, IR, UV-Vis-NIR, elemental analyses, HRMS, as well as single-crystal X-ray diffraction studies （1 and 7）. The cyclic voltammograms of these complexes exhibit two reversible redox processes of [NiLe]0n- and [NIL2]l /2 , and one irreversible process of [NiL2]~n＋. Substituent effects on the redox properties of these complexes, in addi- tion with those of the known complexes [Ni（o-C6Ha（NH）（NPh））2] （8） and [Ni（o-3,5-Butz-C6Hz（NH）2）2] （9）, are identified by comparing the half-wave potentials of the reduction waves, as 1 ~ 9 〈 8 ~ 2 〈 3 〈 4 〈 5 〈 7 〈 6, reflect- ing the ease of reduction of [NIL2] parallels the electron-donating and -withdrawing ability of the substituent group. Reduction of 1 with one or two equivalents of sodium metal in THF has led to the isolation of [Na（THF）3][I] and [Na（THF）3]2[1]. The structure data of these two complexes revealed by low-temperature X-ray crystallography suggest their corresponding electronic structures of [Nill（lL-1 ）（IL2-）]1- and [Ni1]（1L2 ）212-, which are in line with those of [9]n （n = 1-, 2-） suggested by spectroelectrochemical study.     

Coordination compounds of nickel with trithiocyanuric acid. Part IV. Structure of [Ni(pmdien)(ttcH)] (pmdien = N,N,N′,N′,N′′-pentamethyldiethylenetriamine,ttcH3 = trithiocyanuric acid)

Ni^II mixed-ligand complexes of compositions [Ni(pmdien)(ttcH)] (1), [Ni(baphen)₂(ttcH)] · 4H₂O (2), [Ni-(dpa)(ttcH)(H₂O)] (3), [Ni(cyclam)(ttcH)] · 2H₂O (4), [Ni(hexaa)](ttcH) (5) and [Ni(hexab)(ttcH)] · 2H₂O (6), (baphen = 4,7-diphenyl-1,10-phenanthroline, dpa = 2,2-dipyridylamine, cyclam = 1,4,8,11-tetraazacyclotetradecane, hexaa = 1,3,6,9,11,14-hexaazatricyclo[12.2.1.1^6,9]-octadecane, hexab = 1,8-dimethyl-1,3,6,8,10,13-hexaazacyclotetradecane) have been prepared and characterized by means of i.r., u.v.–vis. spectroscopies and magnetochemical measurements. The redox properties of the complexes were studied by cyclic voltammetry. The crystal and molecular structure of [Ni(pmdien)(ttcH)] was determined. The nickel atom is penta-coordinated by three N atoms of pmdien, and by S and N atoms of trithiocyanurate(2–) anion.     

Conjugate additions of functionalized carbanions to the vinylidene groups of [M(CO)4{(Ph2P)2CCH2}] (M = W,Mo or Cr)

Treatment of complexes of the type [M(CO)₄{(Ph₂P)₂CCH₂}] (M = W, Mo or Cr) with functionalized lithium reagents, LiR, followed by hydrolysis gives complexes of the type [M(CO)₄{PH₂P)₂CHCH₂R}] in high yields; R = C₆H₄Me-4, C₆H₄OMe-2, C₆H₃(OMe)₂-2,6, C₆H₄OH-2, C₆H₄(COOH)-2, CH₂COPh or CH₂COMe. IR, and ³¹P and ¹H NMR data are given.     

[Ni(terpy)(H2O)]‐trans‐[Ni‐(μ‐CN)2‐(CN)2]n,a one‐dimensional linear tetra­cyano­nickelate chain

The one‐dimensional chain catena‐poly­[[aqua(2,2′:6′,2′′‐terpyridyl‐κ³N)­nickel(II)]‐μ‐cyano‐κ²N:C‐[bis­(cyano‐κC)nickelate(II)]‐μ‐cyano‐κ²C:N], [Ni(terpy)(H₂O)]‐trans‐[Ni‐μ‐(CN)₂‐(CN)₂]_n or [Ni₂­(CN)₄­(C₁₅H₁₁N₃)(H₂O)], consists of infinite linear chains along the crystallographic [10] direction. The chains are composed of two distinct types of nickel ions, paramagnetic octahedral [Ni(terpy)(H₂O)]²⁺ cations (with twofold crystallographic symmetry) and diamagnetic planar [Ni(CN)₄]^2? anions (with the Ni atom on an inversion center). The [Ni(CN)₄]^2? units act as bidentate ligands bridging through two trans cyano groups thus giving rise to a new example of a trans–trans chain among planar tetra­cyano­nickelate complexes. The coordination geometry of the planar nickel unit is typical of slightly distorted octahedral nickel(II) complexes, but for the [Ni(CN)₄]^2? units, the geometry deviates from a planar configuration due to steric interactions with the ter­pyridine ligands.     

Platinum Complexes of a Borane‐Appended Analogue of 1,1′‐Bis(diphenylphosphino)ferrocene: Flexible Borane Coordination Modes and in situ Vinylborane Formation

A bis(phosphine)borane ambiphilic ligand, [Fe(η⁵‐C₅H₄PPh₂)(η⁵‐C₅H₄PtBu{C₆H₄(BPh₂)‐ortho})] (FcPPB), in which the borane occupies a terminal position, was prepared. Reaction of FcPPB with tris(norbornene)platinum(0) provided [Pt(FcPPB)] ( 1 ) in which the arylborane is η³BCC‐coordinated. Subsequent reaction with CO and CNXyl (Xyl=2,6‐dimethylphenyl) afforded [PtL(FcPPB)] {L=CO ( 2 ) and CNXyl ( 3 )} featuring η²BC‐ and η¹B‐arylborane coordination modes, respectively. Reaction of 1 or 2 with H₂ yielded [PtH(μ‐H)(FcPPB)] in which the borane is bound to a hydride ligand on platinum. Addition of PhC₂H to [Pt(FcPPB)] afforded [Pt(C₂Ph)(μ‐H)(FcPPB)] ( 5 ), which rapidly converted to [Pt(FcPPB′)] ( 6 ; FcPPB′=[Fe(η⁵‐C₅H₄PPh₂)(η⁵‐C₅H₄PtBu{C₆H₄(BPh‐CPh=CHPh‐Z)‐ortho}]) in which the newly formed vinylborane is η³BCC‐coordinated. Unlike arylborane complex 1 , vinylborane complex 6 does not react with CO, CNXyl, H₂ or HC₂Ph at room temperature.     

Reactions of [Cp*Ru(H2O)(NBD)]+ with alkynes

Formal [2 + 2 + 2] addition reactions of [Cp*Ru(H₂O)(NBD)]BF₄ (NBD = norbornadiene) with PhC?CR (R = H, COOEt) give [Cp*Ru(η⁶‐C₆H₅? C₉H₈R)] BF₄ (1a, R = H; 2a, R = COOEt). Treatment of [Cp*Ru(H₂O)(NBD)]BF₄ with PhC?C? C?CPh does not give [2 + 2 + 2] addition product, but [Cp*Ru(η⁶‐C₆H₅? C?C? C?CPh)] BF₄(3a). Treatment of 1a, 2a, 3a with NaBPh₄ affords [Cp*Ru(η⁶‐C₆H₅? C₉H₈R)] BPh₄ (1b, R = H; 2b, R = COOEt) and [Cp*Ru(η⁶‐C₆H₅? C?C? C?CPh)] BPh₄(3b). The structures of 1b, 2b and 3b were determined by X‐ray crystallography. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and structures of the 2-(dimethylsila)pyrimidine derivatives (Ar = Ph, C6H4Bu-4; X = H, SiMe3, Li(hmpa)2, K(thf)3; n = 1, 2)

Five crystalline 2-(dimethylsila)pyrimidine derivatives (Z) have been prepared in excellent 1–4 or satisfactory 5 yield and characterised. The source of each was ultimately Li[CH(SiMe₂R)(SiMe₂OMe)] [R = Me (B) or OMe (I)]. Compound 1 (Z with Ar = Ph, X = SiMe₃, n = 1) was obtained from Z [with Ar = Ph, X = Li(OEt₂), n = 4; previously isolated from B [P.B. Hitchcock, M.F. Lappert, X.-H. Wei, J. Organomet. Chem. 689 (2004) 1342]] and Me₃SiCl. The potassium salt 2 [Z with Ar = C₆H₄Bu^t-4; X = K(thf)₃, n = 2] was made from K[CH(SiMe₃)(SiMe₂OMe)] (C) (via B) and 4-Bu^tC₆H₄CN. Treatment of 2 with 1,2-dibromoethane afforded 3 (Z with Ar = 4-Bu^tC₆H₄; X = H, n = 1); which when reacted with successively n-butyllithium and Me₃SiCl produced 4 (Z with Ar = 4-Bu^tC₆H₄, X = SiMe₃, n = 1). Compound 5 [Z with Ar = 4-Bu^tC₆H₄, X = Li(hmpa)₂, n = 1] resulted from I with 4-Bu^tC₆H₄CN and then OP(NMe₂)₃ (≡ hmpa). Plausible reaction pathways from the appropriate alkali metal alkyl C or I to 2 or 5, respectively, are suggested; these involve regiospecific 1,3-migrations of SiMe₂OMe from C → N and electrocyclic loss of Me₃SiOMe or SiMe₂(OMe)₂, respectively. The X-ray structures of crystalline 1, 2 and 5 are presented.     

Preparation and characterization of mixed amido,carboxylato or thiazolato carbonyl(phosphine)technetium(I) complexes

Summary The complex [Tc(PPh₃)₂(CO)₃Cl] reacts with the lithium salt of amido-carboxylato- and thiazolato-derivatives to give the new complexes (Ar= C₆H₄Me-p or C₆H₄OMe-p), [Tc(PPh₃)₂(CO)₂(amt_1,2)] [amt₁=anion of 2-(methylamino)thiazole; amt₂=anion of 2-4-methoxyphenylamino(thiazole)] and [Tc(PPh₃)₂(CO)₂- (R = Ph₂CH, PhCH₂ or CCl₃). The compounds have been characterized by elemental analysis, and i.r. and¹H n.m.r. spectra.