Reaktionen von Pentafulven‐Komplexen des Titans mit Nitrilen und iso‐Nitrilen — Synthese und Isomerisierungen von σ, π‐Chelatkomplexen mit Cp∼N‐Liganden

Reactions of Pentafulvene Complexes of Titanium with Nitriles and iso‐Nitriles — Synthesis and Isomerizations of σ, π‐Chelat Complexes with Cp∼N‐Ligands The reactions of fulvene complexes Cp*Ti{η⁶—C₅H₄=C(R)(R')}Cl (R = H, R' = tBu ( 1 ); R = Me, R' = iPr ( 4 )) with nitriles and iso‐nitriles, leading to σ, π‐chelat complexes with Cp∼N‐ligands, have been examined and the formed products characterized. Whereas in the reactions of 1 and 4 , respectively, with nitriles a 1, 2‐mono‐insertion of the CN‐group in the Ti—C(R)(R') (Fv) bond is observed, the reaction with iso‐nitrils leads to the insertion of two molecules iso‐nitrile. The nitrile insertion product of 1 is characterized by an imine‐enamine tautomerization. Whereas the primary built meta stable imine species ( 3 ) was only identified by NMR measurements in solution, the enamine tautomer ( 2 ) crystallized from n‐hexane, so that the crystal structure could be determined. The primary formed iminoacyl complex ( 7 ) rearranges due to the electrophilicity of the titanium centre and builds a Ti—N bond with significant N(pπ) → Ti(dπ) bonding character.     

Zur Reaktivität von Titanocenkomplexen [Ti(Cp′)2(η2‐Me3SiC≡CSiMe3)] (Cp′ = Cp,Cp*) gegenüber Benzoldicarbonsäuren

On the Reactivity of Titanocene Complexes [Ti(Cp′)₂(η²‐Me₃SiC≡CSiMe₃)] (Cp′ = Cp, Cp*) towards Benzenedicarboxylic Acids Titanocene complexes [Ti(Cp′)₂(BTMSA)] ( 1a , Cp′ = Cp = η⁵‐C₅H₅; 1b , Cp′ = Cp* = η⁵‐C₅Me₅; BTMSA = Me₃SiC≡CSiMe₃) were found to react with iodine and methyl iodide yielding [Ti(Cp′)₂(μ‐I)₂] ( 2a / b ; a refers to Cp′ = Cp and b to Cp′ = Cp*), [Ti(Cp′)₂I₂] ( 3a / b ) and [Ti(Cp′)₂(Me)I] ( 4a / b ), respectively. In contrast to 2a , complex 2b proved to be highly moisture sensitive yielding with cleavage of HCp* [{Ti(Cp*)I}₂(μ‐O)] ( 7 ). The corresponding reactions of 1a / b with p‐cresol and thiophenol resulted in the formation of [Ti(Cp′)₂{O(p‐Tol)}₂] ( 5a / b ) and [Ti(Cp′)₂(SPh)₂] ( 6a / b ), respectively. Reactions of 1a and 1b with 1,n‐benzenedicarboxylic acids (n = 2–4) resulted in the formation of dinuclear titanium(III) complexes of the type [{Ti(Cp′)₂}₂{μ‐1,n‐(O₂C)₂C₆H₄}] (n = 2, 8a / b ; n = 3, 9a / b ; n = 4, 10a / b ). All complexes were fully characterized analytically and spectroscopically. Furthermore, complexes 7 , 8b , 9a ·THF, 10a / b were also be characterized by single‐crystal X‐ray diffraction analyses.     

Synthese und Insertionsreaktionen von Cp2′HfCl{As(SiMe3)2} (Cp′ = C5H4Me)

Synthesis and Insertion Reactions of Cp₂′HfCl{As(SiMe₃)₂} (Cp′ = C₅H₄Me) The reaction of Cp₂′HfCl₂ (Cp′ = C₅H₄Me) with Li(THF)_2,5As(SiMe₃)₂ (1 : 1) at room temperature gives the terminal hafnocene arsenido complex Cp₂′HfCl{As(SiMe₃)₂} ( 1 ) in high yield. 1 inserts CS₂ and PhNC into the Hf? As bond yielding Cp₂′HfCl{η²-S₂CAs(SiMe₃)₂} ( 2 ) and Cp₂′HfCl{η²-N(Ph)CAs(SiMe₃)₂} ( 3 ). The thermally sensitive complexes 1–3 were characterised spectroscopically and crystal structure determinations were carried out on 1 and 3 which shows the η² bonding mode of the N(Ph)CAs(SiMe₃)₂ ligand in the latter.     

Das dynamische Verhalten des Hydridotris(3,5‐dimethylpyrazolyl)borat‐Liganden in Organopalladium(II)‐Komplexen

The Dynamic Behaviour of Hydridotris(3,5‐dimethylpyrazolyl)borate Ligand in Organopalladium(II) Complexes The new palladium(II) complexes [PdTp*(R)(PPh₃)] (R = Me ( 1 ), C(O)Me ( 1 a ), p‐tol ( 2 ), C(O)p‐tol ( 2 a )) of the tridentate nitrogen ligand Tp* = [HB(3,5‐Me₂pz)₃]^– are non‐rigid molecules on the NMR time scale at room temperature. The ¹H‐NMR spectra at low temperature indicate C_s‐symmetry for 1 whereas 1 a , 2 , 2 a are symmetryless (C₁). The difference in temperature dependence of the ¹H‐NMR spectra is not indicative of a different exchange mechanism. We postulate that in all cases an intramolecular substitution of coordinated and non‐coordinated pyrazolyl substituents takes place. We do not observe a rapid Turnstile rotation of a trigonal bipyramidal intermediate. The crystal structure analysis shows that the coordination of the palladium atom in complex 1 is planar.     

Synthese und Struktur von Ruthenium(II)‐Komplexen mit Triazenido‐ und Pentaazadienido‐Liganden

Synthesis and Crystal Structure of Ruthenium(II) Complexes with Triazenido and Pentaazadienido Ligands The ruthenium(II) triazenido complex [RuCl(ClC₆H₄N₃C₆H₄Cl)(p‐cymene)] ( 1 ) is obtained by the reaction of silver bis(p‐chlorphenyl)triazenid with [RuCl₂(p‐cymene)]₂ in CH₂Cl₂, and forms air stable, orange yellow crystals. It crystallizes as 1 ·CH₂Cl₂ in the orthorhombic space group Pbca with the lattice parameters a = 3134.3(3), b = 2105.7(2), c = 769.15(4) pm and Z = 8. In the diamagnetic mononuclear complex 1 the chelating triazenido ligand coordinates with the atoms N(1) and N(3). p‐Cymene binds η⁶ with its C₆ ring. The reaction of the etherphosphane complex [RuCl₂(Ph₂PCH₂C₄H₇O₂)₂] with 1, 3‐bis(p‐tolyl)triazenid in THF yields the complex [RuCl(tolyl‐N₃‐tolyl)(Ph₂PCH₂C₄H₇O₂)₂] ( 2 ). 2 forms monoclinic, red crystals with the space group P2₁/c and a = 1521.0(2), b = 1451.8(2), c = 2073.7(2) pm, β = 99.29(1)° and Z = 4. It is air stable and diamagnetic. The triazenide ion coordinates with the atoms N(1) and N(3). One of the two etherphosphane ligands is chelating and coordinates with the P atom and one O atom, while the other ligand binds in a monodentate fashion with its P atom, resulting in a coordination number of six for the Ru^II. [Ag(tolyl‐N₅‐tolyl)]₂ reacts in THF with [RuCl₂(C₆H₆)]₂ to afford the air stable, diamagnetic pentaazadienido complex [RuCl(tolyl‐N₅‐tolyl)(C₆H₆)] ( 3 ). 3 forms monoclinic, red crystals with the space group P2₁/c and a = 1462.4(1), b = 1056.51(8), c = 1371.4(1) pm, β = 114.36(1)° and Z = 4. The chelating pentaazadienido ligand coordinates with the atoms N(1) and N(3) at the divalent Ru atom. The benzene molecule binds η⁶ with its π system.     

Darstellung und Kristallstruktur des Azavinylidenderivates Cp*2Ti(CH=CH2)(N=CPh2) ausgehend vom thermisch gebildeten Titanaallenintermediat [Cp*2Ti=C=CH2]

Preparation and Crystal Structure of the Azavinylidene Derivative Cp*₂Ti(CH=CH₂)(N=CPh₂) derived from the Thermally Generated Titanaallene Intermediate [Cp*₂Ti=C=CH₂] The title complex 4 was synthesized by reaction of Benzophenonimin with the titanaallene fragment [Cp*₂Ti=C=CH₂] ( 3 ). Complex 4 was characterized by ¹H and ¹³C NMR spectra and by X-ray structure analysis, respectively.     

1,1′-Disubstituierte Titanocen-dithiolen-Chelate des Typs (η5-Me3EC5H4)2Ti(S2C2R2) (E = C,Si, Ge)

1,1′-Disubstituted Titanocene Dithiolene Chelates of Type (η⁵-Me₃EC₅H₄)₂Ti(S₂C₂R₂) (E = C, Si, Ge) Reaction of the titanocene dichlorides (η⁵-Me₃EC₅H₄)₂TiCl₂ (E = C, 1a ; E = Si, 1b ; E = Ge, 1c ) with the 1,2-dithiolates (NaS)₂C₂H₂, (NaS)₂C₂(CN)₂ or (LiS)₂C₆H₃Me-4 gave the new titanocene dithiolene chelates (η⁵-Me₃EC₅H₄)₂Ti(S₂C₂H₂) ( 2a–c ), (η⁵-Me₃EC₅H₄)₂Ti[S₂C₂(CN)₂] ( 3a–c ) and (η⁵-Me₃EC₅H₄)₂Ti(S₂C₆H₃Me-4) ( 4a–c ). These have been characterized by ¹H NMR, IR, and mass spectroscopy, and have been compared with the unsubstituted η⁵-C₅H₅ analogues 2d, 3d and 4d . Activation energies for the chelate ring inversion in solution of 2a–c, 3a–d and 4a–c have been estimated by temperature-dependent ¹H NMR spectroscopy.     

Darstellung und Strukturen von (η6‐Diaren)TiII‐bis(tetrachloroaluminat)Komplexen,Diaren = Biphenyl oder 3,5,3′,5′‐Tetramethyl‐biphenyl

Syntheses and Crystal Structures of (η⁶‐Diarene)Ti^II‐bis(tetrachloroaluminate) Complexes, Diarene = Biphenyl or 3,5,3′,5′‐Tetramethyl‐biphenyl Syntheses of (η⁶‐diarene)Ti^II(AlCl₄)₂ complexes were performed by the Fischer‐Hafner method. The diarenes employed were biphenyl and 3,5,3′,5′‐tetramethyl‐biphenyl. In each of the resulting complexes, (η⁶‐C₁₂H₁₀)Ti^II(AlCl₄)₂ ( 1 ) and (η⁶‐C₁₆H₁₈)Ti^II(AlCl₄)₂ ( 2 ), only one C₆‐ring of a diarene is coordinatively active. 1 : Space group Pbca, Z = 8, lattice constants at 20 °C: a = 16.864(3), b = 13.931(3), c = 18.807(3) Å; R₁ = 0.048. 2 : Space group P2₁/n, Z = 4, lattice constants at 20 °C: a = 9.775(1), b = 13.720(1), c = 20.214(1) Å; β = 95.50(1)°; R₁ = 0.050.     

Synthese und Molekülstruktur von meso-(1,2,3-Tricyclohexyltriphosphan-1,3-diyl)zirkonocen(IV), Cp2 (Cp = η5−C5H5, Cy = C6H11)

Synthesis and Crystal Structure of meso-(1,2,3-Tricyclohexyltriphosphane-1,3-diyl)zirconocene(IV), Cp₂ (Cp = η⁵?C₅H₅, Cy = C₆H₁₁) Cp₂ZrCl₂ reacts with Li(THF)₂PHCy (Cy = C₆H₁₁) to yield the metallacyclic compound Cp₂ 1. , The ³¹P{¹H} NMR spectrum of 1 , shows a coupling pattern for an A₂X system, indicating the presence of only the meso-forms in solution, which are also present in the solid state. 1 , crystallizes in the monoclinic space group P2₁/n (No. 14) with a = 12.984(8), b = 9.241(7), c = 23.05(1) Å, β = 93.48(4)°, V = 2760.1 ų and four formula units in the unit cell (2718 independent observed reflections, R = 7.3%). The central ZrP₃ ring in 1 , is almost planar. The Zr? P bond lengths of 2.618(4) and 2.628(4) Å are nearly identical.     

Synthese,Struktur und Reaktivität von Tris‐, Bis‐ und Mono(2,4‐dimethylpentadienyl)‐Komplexen des Neodyms,Lanthans und des Yttriums

The tris(2,4‐dimethylpentadienyl) complexes [Ln(η⁵‐Me₂C₅H₅)₃] (Ln = Nd, La, Y) are obtained analytically pure by reaction of the tribromides LnBr₃·nTHF with the potassium compound K(Me₂C₅H₅)(thf)_n in THF in good yields. The structural characterization is carried out by X‐ray crystal structure analysis and NMR‐spectroscopically. The tris complexes can be transformed into the dimeric bis(2,4‐dimethylpentadienyl) complexes [Ln₂(η⁵‐Me₂C₅H₅)₄X₂] (Ln, X: Nd, Cl, Br, I; La, Br, I; Y, Br) by reaction with the trihalides THF solvates in the molar ratio 2:1 in toluene. Structure and bonding conditions are determined for selected compounds by X‐ray crystal structure analysis and NMR‐spectroscopically in general. The dimer‐monomer equilibrium existing in solution was investigated NMR‐spectroscopically in dependence of the donor strength of the solvent and could be established also by preparation of the corresponding monomer neutral ligand complexes [Ln(η⁵‐Me₂C₅H₅)₂X(L)] (Ln, X, L: Nd, Br, py; La, Cl, thf; Br, py; Y, Br, thf). Finally the possibilities for preparation of mono(2,4‐dimethylpentadienyl)lanthanoid(III)‐dibromid complexes are shown and the hexameric structure of the lanthanum complex [La₆(η⁵‐Me₂C₅H₅)₆Br₁₂(thf)₄] is proved by X‐ray crystal structure analysis.     

Synthese,Struktur und Reaktivität von η1und η3‐Allyl‐Rhenium‐Carbonylen

Synthesis, Structure, and Reactivity of η¹‐ and η³‐Allyl Rhenium Carbonyls In (η³‐C₃H₅)Re(CO)₄ one CO ligand can be substituted by PPh₃, pyridine, isocyanide and benzonitrile. With 1,2‐bis(diphenylphosphino)ethylene, 1,1′‐bis(diphenylphosphino)ferrocene and 1,2‐bis(4‐pyridyl)ethane dinuclear ligand bridged complexes are obtained. The η³‐η¹ conversion of the allyl ligand occurs on reaction of (η³‐C₃H₅)Re(CO)₄ with the bidendate ligands 1,2‐bis(diphenylphosphino)ethane and 1,3‐bis(diphenylphosphino)propane and with 2,2′‐bipyridine (L–L) which gives the complexes (η¹‐C₃H₅)Re(CO)₃(L–L). By reaction of (η³‐C₃H₅)Re(CO)₄ with bis(diphenylphosphino)methane the allyl group is protonated and under elemination of propene the complex (OC)₃Re(Ph₂PCHPPh₂)(η¹‐Ph₂PCH₂PPh₂) ( 19 ) with a diphosphinomethanide ligand is formed. On heating solutions of (η³‐C₃H₅)Re(CO)₄ and (η³‐C₃H₅)Re(CO)₃(CN‐2,5‐Me₂C₆H₃) ( 5 ) in methanol the methoxy bridged compounds Re₄(CO)₁₂(OH)(OMe)₃ and Re₂(CO)₄(CN‐2,5‐Me₂C₆H₃)₄(μ‐OMe)₂ ( 20 ) were isolated. The crystal structures of (η³‐C₃H₅)Re(CO)₃(CNCH₂SiMe₃) ( 4 ), [(η³‐C₃H₅)(OC)₃Re]₂‐ (μ‐bis‐(diphenylphosphino)ferrocene) ( 8 ), (η¹‐C₃H₅)Re(CO)₃‐ (bpy) ( 14 ), of 19 , 20 and of (OC)₃Re‐[Ph₂P(CH₂)₃PPh₂]Cl ( 16 ) were determined by X‐ray diffraction.     

Bildung und Struktur von [μ‐(1,2 : 2‐η‐tBu2P–P){Mo(CO)2cp′}2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXIV. Formation and Structure of [μ‐(1,2 : 2‐η‐^tBu₂P–P){Mo(CO)₂cp′}₂] [cp′Mo(CO)₂]₂ (cp′ = C₅H₄^tBu) reacts with ^tBu₂P–P=P(Me)^tBu₂ to yield the compound [μ‐(1,2 : 2‐η‐^tBu₂P–P){Mo(CO)₂cp′}₂], which crystallizes in the space group P2₁2₁2₁ with a = 1202.42(7), b = 1552.48(8), and c = 1765.3(1) pm.     

Synthesis and Structural Characterization of Some Novel Trialkylsilyl‐substituted Lithium Benzyl Complexes [Li(tmeda)][CHRSiMe2R′] (R = Ph, 3,5‐Me2C6H3; R′ = Me,tBu, Ph)

The reactions of PhCH₂SiMe₃ ( 1 ), PhCH₂SiMe₂^tBu ( 2 ), PhCH₂SiMe₂Ph ( 3 ), 3,5‐Me₂C₆H₃CH₂SiMe₃ ( 4 ), and 3,5‐Me₂C₆H₃CH₂SiMe₂^tBu ( 5 ) with ⁿBuLi in tetramethylethylenediamine (tmeda) afford the corresponding lithium complexes [Li(tmeda)][CHRSiMe₂R′] (R, R′ = Ph, Me ( 6 ), Ph, ^tBu ( 7 ), Ph, Ph ( 8 ), 3,5‐Me₂C₆H₃, Me ( 9 ), and 3,5‐Me₂C₆H₃, ^tBu ( 10 )), respectively. The new compounds 5 , 7 , 8 , 9 and 10 have been characterized by ¹H and ¹³C NMR spectroscopy, compounds 7 , 8 and 9 also by X‐ray structure analysis.     

Hydroaluminierung: Synthese,Struktur und Eigenschaften von 1‐Methyl‐cis‐1‐azonia‐5‐alabicyclo[3.3.0]octan und des Alan‐triallylamin‐Adduktes

Hydro‐Alumination: Synthesis, Structure, and Properties of 1‐Methyl‐ cis ‐1‐azonia‐5‐alabicyclo[3.3.0]octane and of the Alan‐triallylamine Adduct The alan‐N‐methyl‐diallylamine adduct ( I ) was obtained by the reaction of N,N‐diallyl‐methyl‐ammoniumchloride with LiAlH₄. Subsequently the reaction product was transformed by intramolecular hydro‐alumination reaction into bis(1‐methyl‐cis‐1‐azonia‐5‐alabicyclo[3.3.0]octane) ( II ). In contrast to I , the bis(alan‐triallylamine) adduct ( III ) does not undergo an analogous hydro‐alumination reaction. The compounds I , II and III were characterized by MS, IR, ¹H‐, ¹³C‐ and ²⁷Al‐NMR spectroscopy, and the X‐ray structures of II and III are reported and discussed.     

Zweikernkomplexe des Typs Mn2(CO)8E(CF3)2E′R (E = P,As; E′ = S,Se, Te): Darstellung und Struktur

Perfluoromethyl Element Ligands. XLII Binuclear Complexes of the Type Mn₂(CO)₈E(CF₃)₂E′R (E = P, As; E′ = S, Se, Te): Synthesis and Structure Complexes of the type Mn₂(CO)₈E(CF₃)₂E′R, in which the groups E(CF₃)₂ and E′R act as bridging ligands, are prepared either by direct reactions of Mn₂(CO)₁₀ with (F₃C)₂EE′R (E = P, As; E′ = S, Se, Te) or by substitution of the iodine bridge in the representatives Mn₂(CO)₈ E(CF₃)₂I (E = P, As) with mercury compounds Hg(E′R)₂. As a rule the binuclear systems contain four‐membered heterocycles (Mn₂EE′). However, the reactions of Mn₂(CO)₁₀ with (F₃C)₂PE′P(CF₃)₂ (E′ = S, Se) yield five‐membered rings [Mn₂P(E′P)]. The compounds have been characterized by spectroscopic (NMR, IR, MS), analytic (C, H) and X‐ray diffraction investigations. The pyramidal Mn₂E′R fragment shows dynamic behaviour in solution via inversion between two identical structures.     

Bildung und Strukturen von [{η2‐tBu2P–P=P–PtBu2}Pt(PR3)2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XVIII. Syntheses and Structures of [{η²‐^tBu₂P–P=P–P^tBu₂}Pt(PR₃)₂] ^tBu₂P–P=P(Me)^tBu₂ reacts with [{η²‐C₂H₄} · Pt(PR₃)₂] as well as with [{η²‐^tBu₂P–P}Pt(PR₃)₂] yielding [{η²‐^tBu₂P–P=P–P^tBu₂}Pt(PR₃)₂]; PR₃ = PMe₃ 3 a , PEtPh₂ 3 b , 1/2 dppe 3 c , PPh₃ 3 d , P(p‐Tol)₃ 3 e . All compounds are characterized by ¹H and ³¹P NMR spectra, for 3 b and 3 d also crystal structure determinations were performed. 3 b crystallizes in the triclinic space group P1 (No. 2) with a = 1212.58(7), b = 1430.74(8), c = 1629.34(11) pm, α = 77.321(6), β = 70.469(5), γ = 87.312(6)°. 3 d crystallizes in the triclinic space group P1 (No. 2) with a = 1122.60(9), b = 1355.88(11), c = 2025.11(14) pm, α = 83.824(9), β = 82.498(9), γ = 67.214(8)°.     

Synthese verbrückter binuklearer Titanocenverbindungen – Kristallstruktur von Cl2Ti[(C5H4)(C5H4)(Me)Si–Si(Me)(C5H4)(C5H4)]TiCl2 · PhMe

Synthesis of Bridged Binuclear Titanocene Compounds – Crystal Structure of Cl₂Ti[(C₅H₄)(C₅H₄)(Me)Si–Si(Me)(C₅H₄)(C₅H₄)]TiCl₂ · PhMe Starting from Cp₂(Me)Si–Si(Me)Cp₂ 1 the complexes X₂Ti[(C₅H₄)(C₅H₄)(Me)Si–Si(Me)(C₅H₄)(C₅H₄)]TiX₂ (X = Cl ( 2 a ); X = Me ( 3 )) were synthesized. The compounds were characterized by means of their ¹H‐ and ¹³C‐n.m.r. and MS‐spectra. The crystal structure of 2 a · PhMe was determined.     

Synthese,Struktur und Photochemie von Olefiniridium(I)‐Komplexen mit Acetylacetonatoliganden

Synthesis, Structure, and Photochemical Behavior of Olefine Iridium(I) Complexes with Acetylacetonato Ligands The bis(ethene) complex [Ir(κ²‐acac)(C₂H₄)₂] ( 1 ) reacts with tertiary phosphanes to give the monosubstitution products [Ir(κ²‐acac)(C₂H₄)(PR₃)] ( 2 – 5 ). While 2 (R = iPr) is inert toward PiPr₃, the reaction of 2 with diphenylacetylene affords the π‐alkyne complex [Ir(κ²‐acac)(C₂Ph₂)(PiPr₃)] ( 6 ). Treatment of [IrCl(C₂H₄)₄] with C‐functionalized acetylacetonates yields the compounds [Ir(κ²‐acacR^1,2)(C₂H₄)₂] ( 8 , 9 ), which react with PiPr₃ to give [Ir(κ²‐acacR^1,2)(C₂H₄)(PiPr₃)] ( 10 , 11 ) by displacement of one ethene ligand. UV irradiation of 5 (PR₃ = iPr₂PCH₂CO₂Me) and 11 (R² = (CH₂)₃CO₂Me) leads, after addition of PiPr₃, to the formation of the hydrido(vinyl)iridium(III) complexes 7 and 12 . The reaction of 2 with the ethene derivatives CH₂=CHR (R = CN, OC(O)Me, C(O)Me) affords the compounds [Ir(κ²‐acac)(CH₂=CHR)(PiPr₃)] ( 13 – 15 ), which on photolysis in the presence of PiPr₃ also undergo an intramolecular C–H activation. In contrast, the analogous complexes [Ir(κ²‐acac)(olefin)(PiPr₃)] (olefin = (E)‐C₂H₂(CO₂Me)₂ 16 , (Z)‐C₂H₂(CO₂Me)₂ 17 ) are photochemically inert.     

Synthese,Strukturen, NMR‐ und EPR‐Untersuchungen der binuklearen Bis(N,N,N‴,N‴‐tetraisobutyl‐N′,N″‐isophthaloylbis(selenoureato))‐Komplexe des NiII und CuII

Synthesis, Structures, NMR and EPR Investigations of Binuclear Bis(N,N,N‴,N‴‐tetraisobutyl‐N′,N″‐isophthaloylbis(selenoureato)) Complexes of Ni^II and Cu^II The synthesis of binuclear Cu^II and Ni^II complexes of the quadridentate ligand N,N,N‴,N‴‐tetraisobutyl‐N′,N″‐isophthaloylbis(selenourea) and their crystal structures are reported. The complexes crystallize monoclinic, P2₁/c (Z = 2). In the EPR spectra of the binuclear Cu^II complex exchange‐coupled Cu^II‐Cu^II pairs were observed. In addition the signals of a mononuclear Cu^II species are observed what will be explained with the assumption of an equilibrium between the binuclear Cu^II‐complex (Cu^II‐Cu^II pairs) and oligomeric complexes with “isolated” Cu^II ions. Detailed ¹³C and ⁷⁷Se NMR investigations on the ligand and the Ni^II complex allow an exact assignment of all signals of the heteroatoms.