Trinuclear Cu(II) and Zn(II) complexes bridged by μ3-carbonato anion

The trinuclear Cu(II) and Zn(II) complexes [(CuTPA),(μ₃-CO,)] (C10₄)₄(1) and [(ZnTPA),(μ₃-C0₃)](C10₄)₄ (2) (TPA = tri(pyridylmethy1)amine) have been synthesized. X-ray structure analysis of the two complexes proves that CO₃ ^2- anion has an unusual triply bridging ligand, bridging three CuTPA and ZnTPA units respectively, and assembles new trinuclear complexes. The CO₃ ²- comes from atmospheric CO₂. The structure of each trinuclear unit consists of three copper or zinc atoms in a five-coordinate triangular hipyramidal environment. The [(CuTPA)₃(μ₃-C0₃) ](C10₄), compound shows a very weak antifemmagnetic coupling. Project supported by the National Natural Science Foundation of China (Grant No.29771021).     

Isolation of N-Heterocyclic Carbene-Stabilized Phosphorus and Arsenic Mononitride

Phosphorus mononitride (PN) and arsenic mononitride (AsN) species supported by two different N-heterocyclic carbenes were prepared: The reaction of [(IDipp)NSiMe₃] [IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene] with PCl₃ or AsCl₃ afforded the dichlorides [(IDipp)NECl₂] (E = P, As) and, after the addition of IMes [IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene], the cationic chloro species [(IDipp)NE(Cl)(IMes)]Cl (E = P, As), which were reduced with potassium graphite (KC₈) to yield the neutral compounds [(IMes)PN(IDipp)] and [(IMes)AsN(IDipp)], which exhibit the typical trans-bent geometry of dicarbene-dielement species in the solid state according to single-crystal X-ray diffraction.     

Reaction of the N‐heterocyclic carbene, 1,3‐dimesityl‐ imidazol‐2‐ylidene,with a uranyl triflate complex,UO2(OTf)2(thf)3

The N‐heterocyclic carbene, 1,3‐dimesityl‐imidazol‐2‐ylidene (IMes) reacts with tetrahydrofuran (THF) in the presence of an oxidizing uranyl triflate complex, UO₂(OTf)₂(thf)₃ (^?OTf = ^?OSO₂CF₃), to give 1,4‐bis(1,3‐dimesityl‐2‐imidazolium)‐1,3‐butadiene bis(trifluoromethanesulfonate), formally understood as the coupling product of two equivalents of IMes with [CH?CH? CH?CH](OTf)₂. Copyright © 2005 John Wiley & Sons, Ltd.     

Investigation of the Catalytic Activity of a 2‐Phenylidenepyridine Palladium(II) Complex Bearing 4,5‐Dicyano‐1,3‐bis(mesityl)imidazol‐2‐ylidene in the Mizoroki‐Heck Reaction

The phenylidenepyridine (ppy) palladacycles [PdCl(ppy)(IMes)] ( 4 ) [IMes = 1,3‐bis(mesityl)imidazol‐2‐ylidene] and [PdCl(ppy){(CN)₂IMes}] ( 6 ) [(CN)₂IMes = 4,5‐dicyano‐1,3‐bis(mesityl)imidazol‐2‐ylidene] were prepared by facile two step syntheses, starting with the reaction of palladium(II) chloride with 2‐phenylpyridine followed by subsequent addition of the NHC ligand to the precatalyst precursor [PdCl(ppy)]₂. Suitable crystals for the X‐ray analysis of the complexes 4 and 6 were obtained. It was shown that 6 has a shorter NHC‐palladium bond than the IMes complex 4 . The difference of the palladium carbene bond lengths based on the higher π‐acceptor strength of (CN)₂IMes in comparison to IMes. Thus, (CN)₂IMes should stabilize the catalytically active central palladium atom better than IMes. As a measure for the π‐acceptor strength of (CN)₂IMes compared to IMes, the selone (CN)₂IMes · Se ( 7 ) was prepared and characterized by ⁷⁷Se‐NMR spectroscopy. The π‐acceptor strength of 7 was illuminated by the shift of its ⁷⁷Se‐NMR signal. The ⁷⁷Se‐NMR signal of 7 was shifted to much higher frequencies than the ⁷⁷Se‐NMR signal of IMes · Se. Catalytic experiments using the Mizoroki‐Heck reaction of aryl chlorides with n‐butyl acrylate showed that 6 is the superior performer in comparison to 4 . Using complex 6 , an extensive substrate screening of 26 different aryl bromides with n‐butyl acrylate was performed. Complex 6 is a suitable precatalyst for para‐substituted aryl bromides. The catalytically active species was identified by mercury poisoning experiments to be palladium nanoparticles.     

Monomeric Magnesium and Calcium Complexes containing the Rigid,Dianionic 1, 2‐Bis[(2, 5‐di‐tert‐butylphenyl)imino]acenaphthene (dtb‐BIAN) and 1, 2‐Bis[(2‐biphenyl)imino]acenaphthene (bph‐BIAN) Ligands

The new rigid bidentate nitrogen ligands 1, 2‐bis[(2, 5‐di‐tert‐butylphenyl)imino]acenaphthene ( 1 ) (dtb‐BIAN) and 1, 2‐bis[(2‐biphenyl)imino]acenaphthene ( 2 ) (bph‐BIAN) have been synthesized by condensation of 1, 2‐acenaphthylenedione with 2, 5‐di‐tert‐butylaniline and 2‐aminobiphenyl, respectively. Reduction of 1 and 2 with magnesium and calcium results in the formation of the monomeric metal complexes [(dtb‐BIAN)Mg(THF)₂] ( 3 ), [(bph‐BIAN)Mg(DME)₂] ( 4 ), and [(bph‐BIAN)Ca(THF)₃] ( 5 ). Compounds 1 — 5 have been characterized by C/H analyses, IR, ¹H NMR, and ¹³C NMR spectra, the structures of 2 , 3 , and 5 have been estimated by single crystal X‐ray diffraction.     

Aggregation and Degradation of White Phosphorus Mediated by N‐Heterocyclic Carbene Nickel(0) Complexes

The reaction of zerovalent nickel compounds with white phosphorus (P₄) is a barely explored route to binary nickel phosphide clusters. Here, we show that coordinatively and electronically unsaturated N‐heterocyclic carbene (NHC) nickel(0) complexes afford unusual cluster compounds with P₁, P₃, P₅ and P₈ units. Using [Ni(IMes)₂] [IMes=1,3‐bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene], electron‐deficient Ni₃P₄ and Ni₃P₆ clusters have been isolated, which can be described as superhypercloso and hypercloso clusters according to the Wade–Mingos rules. Use of the bulkier NHC complexes [Ni(IPr)₂] or [(IPr)Ni(η⁶‐toluene)] [IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene] affords a closo‐Ni₃P₈ cluster. Inverse‐sandwich complexes [(NHC)₂Ni₂P₅] (NHC=IMes, IPr) with an aromatic cyclo‐P₅^? ligand were identified as additional products.     

Zur Addition von Übergangsmetallhalogeniden an Acetylacetonate zweiwertiger Metallionen

Addition of Transition Metal Dihalides to Acetylacetonates of Divalent Metal Ions Transition metal dihalides ^aM^IIX₂ (FeCl₂, CoCl₂ NiBr₂ etc.) are added by the chelates M^II(acac)₂ under formation of binuclear complexes (THF)₂M^II(acac)₂(^aM^IIX₂). The octahedral and the tetrahedral centre of these compounds are connected by tridentate oxygen atoms of the two acetylacetonato ligands which are simultaneously included in four-membered rings (M^IIOM^II). The addition is combined with a deformation of the octahedral centre, as a prerequisite of a closest package of the atoms within the M^IIOM^II-ring. In the trinuclear complex (THF)₂Ni(acac)₂(HgCl₂)₂ III the interaction between the three coordination centres is weak. No structural change of the octahedral centre (THF)₂Ni(acac)₂ is found, but the HgCl₂-groups diverge slightly from linearity (Cl? Hg? Cl 171.1°). No binuclear complexes with a central ion of the oxidation state III in the octahedral centre were obtained. One reason is the lowered donor strength of the bidentate Lewis base function of the octahedral centre [(THF)₂Mⁿ⁺(acac)₂]^n-2 with M⁺³ as a centralatom. Reacting systems with di- and trivalent ions prefer ionic complexes, as it is shown by the formation of [(THF)₂V(acac)₂][(THF)CoCl₃] IV from VCl₃ and Co(acac)₂. The crystal structures of (THF)₂Co(acac)₂CoCl₂ II and [(THF)₂V(acac)₂][(THF)CoCl₃] IV were determined by x-ray diffraction. II : orthorhombic-primitive; space group P2₁2₁2₁, Z = 4; a = 967.4(2), b = 1453.4(3), c = 1715.9(4) pm; R = 0.049 for 3084 observed reflections. IV : triclinic; space group P1, Nr. 2; Z = 2; a = 871,5(2), b = 930,6(3), c = 1865,6(6) pm; α = 101,70(2), b? = 92,45(2), γ = 91,06(2)°; R = 0,060 für 4221 observed reflections.     

Reduction of Digallane [(dpp‐bian)Ga?Ga(dpp‐bian)] with Group 1 and 2 Metals

The reduction of digallane [(dpp‐bian)Ga? Ga(dpp‐bian)] ( 1 ) (dpp‐bian=1,2‐bis[(2,6‐diisopropylphenyl)imino]acenaphthene) with lithium and sodium in diethyl ether, or with potassium in THF affords compounds featuring the direct alkali metal–gallium bonds, [(dpp‐bian)Ga? Li(Et₂O)₃] ( 2 ), [(dpp‐bian)Ga? Na(Et₂O)₃] ( 3 ), and [(dpp‐bian)Ga? K(thf)₅] ( 7 ), respectively. Crystallization of 3 from DME produces compound [(dpp‐bian)Ga? Na(dme)₂] ( 4 ). Dissolution of 3 in THF and subsequent crystallization from diethyl ether gives [(dpp‐bian)Ga? Na(thf)₃(Et₂O)] ( 5 ). Ionic [(dpp‐bian)Ga]^?[Na([18]crown‐6)(thf)₂]⁺ ( 6 a ) and [(dpp‐bian)Ga]^?[Na(Ph₃PO)₃(thf)]⁺ ( 6 b ) were obtained from THF after treatment of 3 with [18]crown‐6 and Ph₃PO, respectively. The reduction of 1 with Group 2 metals in THF affords [(dpp‐bian)Ga]₂M(thf)_n (M=Mg ( 8 ), n=3; M=Ca ( 9 ), Sr ( 10 ), n=4; M=Ba ( 11 ), n=5). The molecular structures of 4 – 7 and 11 have been determined by X‐ray crystallography. The Ga? Na bond lengths in 3 – 5 vary notably depending on the coordination environment of the sodium atom.     

Application of the Redox-Transmetalation Procedure to Access Divalent Lanthanide and Alkaline-Earth NHC Complexes**

Divalent lanthanide and alkaline-earth complexes supported by N-heterocyclic carbene (NHC) ligands have been accessed by redox-transmetalation between air-stable NHC-AgI complexes and the corresponding metals. By using the small ligand 1,3-dimethylimidazol-2-ylidene (IMe), two series of isostructural complexes were obtained: the tetra-NHC complexes [LnI₂(IMe)₄] (Ln=Eu and Sm) and the bis-NHC complexes [MI₂(IMe)₂(THF)₂] (M=Yb, Ca and Sr). In the former, distortions in the NHC coordination were found to originate from intermolecular repulsions in the solid state. Application of the redox-transmetalation strategy with the bulkier 1,3-dimesitylimidazol-2-ylidene (IMes) ligand yielded [SrI₂(IMes)(THF)₃], while using a similar procedure with Ca metal led to [CaI₂(THF)₄] and uncoordinated IMes. DFT calculations were performed to rationalise the selective formation of the bis-NHC adduct in [SrI₂(IMe)₂(THF)₂] and the tetra-NHC adduct in [SmI₂(IMe)₄]. Since the results in the gas phase point towards preferential formation of the tetra-NHC complexes for both metal centres, the differences between both arrangements are a result of solid-state effects such as slightly different packing forces.     

Fluorination Reactions at a Platinum Carbene Complex: Reaction Routes to SF3, S(=O)F and Fluorido Complexes

The electron-rich Pt complex [Pt(IMes)₂] (IMes: [1,3-bis(2,4,6-trimethylphenyl)-2-imidazolinylidine]) can be used as precursor for the syntheses of a variety of fluorido ligand containing compounds. The sulfur fluoride SF₄ undergoes a rapid oxidative addition at Pt⁰ to yield trans-[Pt(F)(SF₃)(IMes)₂]. A photolytic reaction of SF₆ at [Pt(IMes)₂] in the presence of IMes gave the fluorido complexes trans-[Pt(F)₂(IMes)₂] and trans-[Pt(F)(SF₃)(IMes)₂] along with trans-[Pt(F)(SOF)(IMes)₂] and trans-[Pt(F)(IMes’)(IMes)] (IMes’: cyclometalated IMes ligand), the latter being products produced by reaction with adventitious water. trans-[Pt(F)(SOF)(IMes)₂] and trans-[Pt(F)₂(IMes)₂] were synthesized independently by treatment of [Pt(IMes)₂] with SOF₂ or XeF₂. A reaction of [Pt(IMes)₂] with a HF source gave trans-[Pt(H)(F)(IMes)₂], and an intermediate bifluorido complex trans-[Pt(H)(FHF)(IMes)₂] was identified. Compound trans-[Pt(H)(F)(IMes)₂] converts in the presence of CsF into trans-[Pt(F)(IMes’)(IMes)].     

Gallium and Indium Arsanido Metalates: Compounds Derived from the Zinc Blende and Wurtzite Structure

The reaction of InCl₃ with LiAs^tBu₂ in THF at –78 °C gives the indium arsenide Cl₂InAs^tBu₂ ( 1 ), which is dimer in solution and solid state. The corresponding reaction of InCl₃ with Li₂As^tBu leads to the metalate [Li(THF)₄]₂[(InCl)₄(InCl₂)₂(As^tBu)₆] ( 2 ). The arsanido metalate [Li(THF)₄]₂[(GaCl₂)₆(As^tBu)₄] · THF ( 3 · THF) could be obtained by treatment of GaCl₃ with Li₂As^tBu in the molar ratio 6 : 4. A comparable reaction with TlCl₃ and LiAsR₂ or LiPR₂, respectively, was not successful because of the oxidation potential of TlCl₃. The reaction mixture of TlCl₃ and LiPPh₂ for example gives TlCl and Ph₂P–PPh₂ ( 4 ) as redox products. The octaarsane [As(As^tBu)₃]₂ ( 5 ) can be obtained by the treatment of ^tBuAs(SiMe₃)₂ with TlCl₃ in THF. 1–5 were characterized by NMR, IR and MS techniques. The X‐ray analyses of 2 and 3 · THF show that 2 can be derived from the wurtzite structure while the zinc blende structure is the model for 3 with a adamantane‐like dianion [(GaCl₂)₆(As^tBu)₄]^2–.     

Structural diversity of polynuclear MgxOy cores in magnesium phenoxide complexes

The binuclear complex bis(2,6‐di‐tert‐butyl‐4‐methylphenolato)‐1κO ,2κO‐(1,2‐dimethoxyethane‐1κ²O ,O ′)bis(μ‐phenylmethanolato‐1:2κ²O :O )(tetrahydrofuran‐2κO )dimagnesium(II), [Mg₂(C₇H₇O)₂(C₁₅H₂₃O)₂(C₄H₈O)(C₄H₁₀O₂)] or [(BHT)(DME)Mg(μ‐OBn)₂Mg(THF)(BHT)], (I), was obtained from the complex [(BHT)Mg(μ‐OBn)(THF)]₂ by substitution of one tetrahydrofuran (THF) molecule with 1,2‐dimethoxyethane (DME) in toluene (BHT is O‐2,6‐^t Bu₂‐4‐MeC₆H₄ and Bn is benzyl). The trinuclear complex bis(2,6‐di‐tert‐butyl‐4‐methylphenolato)‐1κO ,3κO‐tetrakis(μ‐2‐methylphenolato)‐1:2κ⁴O :O ;2:3κ⁴O :O‐bis(tetrahydrofuran)‐1κO ,3κO‐trimagnesium(II), [Mg₃(C₇H₇O)₄(C₁₅H₂₃O)₂(C₄H₈O)₂] or [(BHT)₂(μ‐O‐2‐MeC₆H₄)₄(THF)₂Mg₃], (II), was formed from a mixture of Bu₂Mg, [(BHT)Mg(ⁿ Bu)(THF)₂] and 2‐methylphenol. An unusual tetranuclear complex, bis(μ₃‐2‐aminoethanolato‐κ⁴O :O :O ,N )tetrakis(μ₂‐2‐aminoethanolato‐κ³O :O ,N )bis(2,6‐di‐tert‐butyl‐4‐methylphenolato‐κO )tetramagnesium(II), [Mg₄(C₂H₆NO)₆(C₁₅H₂₃O)₂] or Mg₄(BHT)₂(OCH₂CH₂NH₂)₆, (III), resulted from the reaction between (BHT)₂Mg(THF)₂ and 2‐aminoethanol. A polymerization test demonstrated the ability of (III) to catalyse the ring‐opening polymerization of ϵ‐caprolactone without activation by alcohol. In all three complexes (I)–(III), the BHT ligand demonstrates the terminal κO‐coordination mode. Complexes (I), (II) and (III) have binuclear rhomboid Mg₂O₂, trinuclear chain‐like Mg₃O₄ and bicubic Mg₄O₆ cores, respectively. A survey of the literature on known polynuclear Mg_x O_y core types for ArO–Mg complexes is also presented.     

Synthesen und Reaktionen von Aluminiumalkoxid‐Verbindungen

Syntheses and Reactions of Aluminium Alkoxide Compounds Al(O^cHex)₃ ( 1 ) can be synthesized by the reaction of Al with cyclohexanol under evolving of H₂ in boiling xylene. [Li{Al(OCH₂Ph)₄}] ( 2 ) was obtained by treatment of PhCH₂OH with a 1 M solution of LiAlH₄ in THF. [{(THF)Li}₂{Al(O^tBu)₄}Cl] ( 3 ) is the result of the reaction of four equivalents of LiO^tBu on AlCl₃ in THF. 3 is the educt for the reactions with the Lewis‐acids InCl₃ and FeCl₃ in THF leading to the metalates [{(THF)₂Li}₂{Al(O^tBu)₄}] · [MCl₄] [M = In ( 4 ), Fe ( 5 )]. The attempt to react InCl₃ with four equivalents of LiO^tBu leads to only one isolated and characterized product, the complex [Li₄(O^tBu)₃(THF)₃Cl]₂ · THF ( 6 · THF), which can also be synthesized by the treatment of LiCl with three equivalents of LiO^tBu in THF. 1–6 · THF were characterized by NMR, IR and MS techniques as well as by X‐ray structure determinations. According to them, 1 , which is tetrameric in solution, is the first structurally characterized example of the proposed trimer form of aluminium alkoxides [ROAl{Al(OR)₄}₂] with a central trigonal bipyramidal coordinated Al atom. 2 forms a coordination polymer with a distorted tetrahedral coordination sphere of Li and Al, running along [100]. The trinuclear structure skeleton [{(THF)₂Li}₂{Al(O^tBu)₄}]⁺ is still present in the isotypical metalates 4 and 5 . The counter ions [MCl₄]^– possess nearly T_d symmetry. The remarkable structural motif of 6 · THF are two heterocubanes [Li₄(O^tBu)₃(THF)₃Cl] dimerized by Li–Cl bonds.     

Synthese und Struktur der Komplexe [(n‐Bu)4N]2[{(THF)Cl4Re≡N}2PdCl2], [Ph4P]2[(THF)Cl4Re≡N‐PdCl(μ‐Cl)]2 und [(n‐Bu)4N]2[Pd3Cl8]

Synthesis and Crystal Structure of the Complexes [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}₂PdCl₂], [Ph₄P]₂[(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂ and [(n‐Bu)₄N]₂[Pd₃Cl₈] The threenuclear complex [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}₂ PdCl₂] ( 1 ) is obtained in THF by the reaction of PdCl₂(NCC₆H₅)₂ with [(n‐Bu)₄N][ReNCl₄] in the molar ration 1:2. It forms orange crystals with the composition 1· THF crystallizing in the monoclinic space group C2/c with a = 2973.3(2); b = 1486.63(7); c = 1662.67(8)pm; β = 120.036(5)° and Z = 4. If the reaction is carried out with PdCl₂ instead of PdCl₂(NCC₆H₅)₂, orange crystals of hitherto unknown [(n‐Bu)₄N]₂[Pd₃Cl₈] ( 3 ) are obtained besides some crystals of 1· THF. 3 crystallizes with the space group P1¯ and a = 1141.50(8), b = 1401.2(1), c = 1665.9(1)pm, α = 67.529(8)°, β = 81.960(9)°, γ = 66.813(8)° and Z = 2. In the centrosymmetric complex anion [{(THF)Cl₄Re≡N}₂PdCl₂]^2— a linear PdCl₂ moiety is connected in trans arrangement with two complex fragments [(THF)Cl₄Re≡N]^— via asymmetric nitrido bridges Re≡N‐Pd. For Pd(II) thereby results a square‐planar coordination PdCl₂N₂. The linear nitrido bridges are characterized by distances Re‐N = 163.8(7)pm and Pd‐N = 194.1(7)pm. The crystal structure of 3 contains two symmetry independent, planar complexes [Pd₃Cl₈]^2— with the symmetry 1¯, in which the Pd atoms are connected by slightly asymmetric chloro bridges. By the reaction of equimolar amounts of [Ph₄P][ReNCl₄] and PdCl₂(NCC₆H₅)₂ in THF brown crystals of the heterometallic complex, [Ph₄P]₂[(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂ ( 2 ) result. 2 crystallizes in the monoclinic space group P2₁/n with a = 979.55(9); b = 2221.5(1); c = 1523.1(2)pm; β = 100.33(1)° and Z = 2. In the central unit ClPd(μ‐Cl)₂PdCl of the centrosymmetric anionic complex [(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂^2— the coordination of the Pd atoms is completed by two nitrido bridges Re≡N‐Pd to nitrido complex fragments [(THF)Cl₄Re≡N]^— forming a square‐planar arrangement for Pd(II). The distances in the linear nitrido bridges are Re‐N = 163.8(9)pm and Pd‐N = 191.5(9)pm.     

Halogen Complexes of Anionic N-Heterocyclic Carbenes

The lithium complexes [(WCA-NHC)Li(toluene)] of anionic N-heterocyclic carbenes with a weakly coordinating anionic borate moiety (WCA-NHC) reacted with iodine, bromine, or CCl₄ to afford the zwitterionic 2-halogenoimidazolium borates (WCA-NHC)X (X=I, Br, Cl; WCA=B(C₆F₅)₃, B{3,5-C₆H₃(CF₃)₂}₃; NHC=IDipp=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene, or NHC=IMes=1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene). The iodine derivative (WCA-IDipp)I (WCA=B(C₆F₅)₃) formed several complexes of the type (WCA-IDipp)I ⋅ L (L=C₆H₅Cl, C₆H₅Me, CH₃CN, THF, ONMe₃), revealing its ability to act as an efficient halogen bond donor, which was also exploited for the preparation of hypervalent bis(carbene)iodine(I) complexes of the type [(WCA-IDipp)I(NHC)] and [PPh₄][(WCA-IDipp)I(WCA-NHC)] (NHC=IDipp, IMes). The corresponding bromine complex [PPh₄][(WCA-IDipp)₂Br] was isolated as a rare example of a hypervalent (10-Br-2) system. DFT calculations reveal that London dispersion contributes significantly to the stability of the bis(carbene)halogen(I) complexes, and the bonding was further analyzed by quantum theory of atoms in molecules (QTAIM) analysis.     

Trinuclear magnesium complexes stabilized by aminoalkoxide ligands

New magnesium complexes, [Et₂Mg₃(dmamp)₄] (1) and [(CH₂=CH)₂Mg₃(dmamp)₄] (2), were prepared by the reaction of alkylmagnesium bromide with sodium 1-dimethylamino-2-methyl-2-propoxide [Na(dmamp)] in THF. Complexes 1 and 2 were characterized by ¹H and ¹³C NMR spectroscopies, FTIR spectroscopy, elemental analysis, and single-crystal X-ray diffraction (XRD) analysis. The XRD analysis showed that these complexes are trinuclear where the alkoxy O is the μ₂-O bridge between the Mg ions. Among the three metal centers, the two terminal Mg ions are five coordinate and have a square–pyramidal geometry, whereas the central Mg is four coordinate with a distorted tetrahedral geometry. The combination of ethyl and vinyl groups with sterically bulky aminoalkoxide ligands plays an important role in stabilizing the molecule.     

Aluminum hydrides with radical-anionic and dianionic acenaphthene-1,2-diimine ligands

The reaction of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-bian) with LiAlH₄ affords two products regardless of the solvent used (tetrahydrofuran or diethyl ether). These products were isolated as green and colorless crystals. Green crystals of the complex [(dpp-bian)Al(H)₂Li(THF)₃] (1) were obtained from tetrahydrofuran; colorless crystals of the complex [{dpp-bian(H₂)}Al(H)₂Li(Et₂O)₂] (2), from diethyl ether. The reactions of compound 1 with 2,6-di-tert-butyl-4-methylphenol and benzophenone gave monohydrides [(dpp-bian)Al(H)(OC₆H₂-2,6-Bu₂ ^t-4-Me)][Li(THF)₄] (3) and [(dpp-bian)Al(H)(OCHPh₂)- Li(THF)₂] (4), respectively. The diamagnetic aluminum hydride [(dpp-bian)AlH(THF)] (5) was synthesized by the reaction of dichloroalane HAlCl₂ (in situ) with the disodium salt of dpp-bian in THF; the paramagnetic hydride [(dpp-bian)AlH(Cl)] (6) containing the dpp-bian radical anion was synthesized by the reaction of the monosodium salt (dpp-bian)Na with monochloroalane H₂AlCl (in situ) in diethyl ether. The reaction of compound 6 with tert-butyllithium gives the complex [(dpp-bian)AlBu^t(Et₂O)] (7). Diamagnetic derivatives 1—5 and 7 were characterized by ¹Н NMR spectroscopy; paramagnetic compound 6, by ESR spectroscopy. The molecular structures of compounds 1—7 were determined by single-crystal X-ray diffraction.     

Towards a New Family of Photoluminescent Organozinc 8‐Hydroxyquinolinates with a High Propensity to Form Noncovalent Porous Materials

We report on investigations of reactions of tBu₂Zn with 8‐hydroxyquinoline (q‐H) and the influence of water on the composition and structure of the final product. A new synthetic approach to photoluminescent zinc complexes with quinolinate ligands was developed that allowed the isolation of a series of structurally diverse and novel alkylzinc 8‐hydroxyquinolate complexes: the trinuclear alkylzinc aggregate [tBuZn(q)]₃ ( 1₃ ), the pentanuclear oxo cluster [(tBu)₃Zn₅(μ₄‐O)(q)₅] ( 2 ), and the tetranuclear hydroxo cluster [Zn(q)₂]₂[tBuZn(OH)]₂ ( 3 ). All compounds were characterized in solution by ¹H NMR, IR, UV/Vis, and photoluminescence (PL) spectroscopy, and in the solid state by X‐ray diffraction, TGA, and PL studies. Density functional theory calculations were also carried out for these new Zn^II complexes to rationalize their luminescence behavior. A detailed analysis of the supramolecular structures of 2 and 3 shows that the unique shape of the corresponding single molecules leads to the formation of extended 3D networks with 1D open channels. Varying the stoichiometry, shape, and supramolecular structure of the resulting complexes leads to changes in their spectroscopic properties. The close‐packed crystal structure of 1₃ shows a redshifted emission maximum in comparison to the porous crystal structure of 2 and the THF‐solvated structure of 3 .     

Ein dreikerniger Zinkkomplex mit ZnS4‐, ZnS3O‐ und ZnS2NO‐Koordinationen

A Trinuclear Zinc Complex with ZnS₄, ZnS₃O, and ZnS₂NO Coordinations The reaction between the tris(thioimidazolyl)borate complex [Tt^tBuZn‐OClO₃] and 2‐pyridylbenzylalcohol (PBAH) yields the compound[(Tt^tBu)₃Zn₃(PBA)] (ClO₄)₂. In its trinuclear complex cation tris(thioimidazolyl)borate ligands, which adopt the umbrella conformation, bridge the zinc ions, which have the three different coordinations ZnS₄, ZnS₃O and ZnS₂NO.     

Structures and magnetic relaxation properties of cyclopentadienyl/β-diketonate/trispyrazolylborate hybridized dysprosium single-molecule magnets

The combination of cyclopentadiene, β-diketonate and tripyrazoylborate ligands with dysprosium ion afforded five mononuclear compounds: [(Cp)₂Dy(Tp*)] (1Dy), [(Cp)Dy(Tp*)Cl(THF)] (2Dy), [(Cp)Dy(Tp)Cl(THF)] (3Dy), [(DBM)Dy(Tp)Cl(THF)] (4Dy), [{(Tp)Dy(DBM)₂(H₂O)}·THF] (5Dy) (Cp = cyclopentadiene; Tp* = hydrotris(3,5-dimethyl-1-pyrazolyl)borate; Tp = hydrotris(1-pyrazolyl)borate; DBM = dibenzoylmethanoate). Magnetic study revealed that 1Dy and 3Dy exhibited typical butterfly-type hysteresis. AC susceptibility study combined with ab initio calculations indicated that the magnetic relaxation behaviors of 1Dy–4Dy were governed by the Orbach and Raman processes under applied DC field. Moreover, 3Dy showed two-step magnetic relaxation, which was attributed to the static disordering of the coordinated THF molecule. Magnetic anisotropy analysis indicated that it was the relative strength of the interactions between Dy^III and surrounding ligands that determined the orientation of the magnetic easy axis.