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.     

Bis[N,N′‐bis(2‐nitrocinnamaldehyde)phenylenediimine]copper(I) Perchlorate

The complex [Cu(nitroca₂ph)₂]ClO₄, where nitroca₂ph is N,N′‐bis(2‐nitrocinnamaldehyde)phenylenediimine, crystallizes in the triclinic space group with a = 13.167(1), b = 13.209(1), c = 14.465(1) Å, α = 83.209(9)°, β = 68.438(2)°, γ = 70.803(2)°, V = 2209.4(3) ų, Z = 2, D_calc = 1.527 mg/m³. The coordination polyhedron about the Cu(I) atom is best described as a distorted tetrahedron. 2‐nitroca₂en acts as a bidentate ligand coordinating via two N atoms to the copper. The four Cu–N distances are 2.04 (2), 2.038(2), 2.046(2), and 2.062(2) Å.     

Reactivity of Lanthanoid Aryloxide Complexes: Isolation of a 1,2‐Dimethoxyethane Cleavage Product

[Yb(OAr)₂(μ‐OMe)(DME)]₂ ( 1 ) (OAr = 2,6‐di‐iso‐propylphenolate) was synthesised via a redox transmetallation ligand exchange reaction between ytterbium metal, diphenylmercury and 2,6‐di‐isopropylphenol in DME. The source of the methoxy groups is from cleavage of DME, and the C‐O bond activation is unexpected given that the reaction was undertaken at ambient temperature. Each Yb³⁺ metal ion in 1 is six coordinate, and the coordination arrangement around each metal ion is distorted trigonal antiprismatic with Yb‐O(OMe) bond lengths (2.191(2) and 2.258(2) Å) shorter than the Yb‐O(aryloxide) bond distances (2.094(2) and 2.074(2) Å).     

Synthesis and Molecular Structure of Two Zinc Complexes of 1,2‐Bis[(trimethylsilyl)imino]acenaphthene

The reaction of 1,2‐bis[(trimethylsilyl)imino]acenaphthene ( 1 , tms‐BIAN) with ZnCl₂ and ZnI₂ in THF and Et₂O afford (tms‐BIAN)ZnCl₂ ( 2 ) and (tms‐BIAN)ZnI₂ ( 3 ), respectively. The compounds 2 and 3 were characterized by IR‐ and NMR spectroscopy as well as by single crystal X‐ray analysis.     

Nickel‐Catalyzed Enantioselective CC Bond Formation through CO Cleavage in Aryl Esters

We report the first enantioselective C? C bond formation through C? O bond cleavage using aryl ester counterparts. This method is characterized by its wide substrate scope and results in the formation of quaternary stereogenic centers with high yields and asymmetric induction.     

[(C7H13N2)2Al]BPh4 – ein spirozyklischer Vinamidin‐Komplex des Aluminiums

[(C₇H₁₃N₂)₂Al]BPh₄ – a Spirocyclic Vinamidine Complex of Aluminum (C₇H₁₃N₂)AlH₂ ( 3 ) reacts with the vinamidinium salts C₇H₁₄N₂ · HX [ 4 , X = BPh₄ ( a ), Cl ( b )] to give the spirocyclic vinamidine aluminum complexes [(C₇H₁₃N₂)₂Al]BPh₄ ( 5 a ) and (C₇H₁₃N₂)₂AlCl ( 5 b ); the crystal structure of 5 a is reported.     

Sodium cation migration above the diimine pi-system of solvent coordinated dpp-BIAN sodium aluminum complexes (dpp-BIAN=1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene)

The reactions of the disodium salt of the 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-BIAN) ligand with one equivalent of Me2AlCl in diethyl ether, toluene, and benzene produced the complexes [Na(Et2O)2(dpp-BIAN)AlMe2] (1), [Na(eta6-C7H8)(dpp-BIAN)AlMe2] (2) and [Na(eta6-C6H6)(dpp-BIAN)AlMe2] (3), respectively. Recrystallization of 1 from hexane afforded solvent-free [{Na(dpp-BIAN)AlMe2}n] (4) or [Na(Et2O)(dpp-BIAN)AlMe2] (5) depending on the temperature of the solvent. The molecular structures of 1-5 have been determined by single-crystal X-ray diffraction. The sodium cation coordinates either one of the naphthalene rings (1) or the diimine part of the dpp-BIAN ligand (2-5). In the complexes 2 and 3, the sodium cation additionally coordinates the toluene (2) or benzene molecule (3) in an eta6-fashion.     

Novel Octahedral Bis[2‐(1‐aziridinyl)ethanol‐κ2N,O] Complexes of Cobalt(II)

The synthesis and molecular structure of trans‐{bis[(acetato‐κO)‐(2‐(1‐aziridinyl)ethanol‐κ²N,O)]}cobalt(II) ( 4 ) and cis‐{bis[chlorido‐(2‐(1‐aziridinyl)ethanol‐κ²N,O)]}cobalt(II) ( 5 ) is reported. Both neutral chelate complexes are prepared from the corresponding Co^II salt [CoX₂; X = OAc ( 1 ), Cl ( 2 )] and 2‐(1‐aziridinyl)ethanol (azolH, 3 ) in dry dichloromethane. A third, ionic complex, cis‐{bis[aqua‐(2‐(1‐aziridinyl)ethanol‐κ²N,O)]}cobalt(II) diacetate ( 6 ) is formed from 4 in the presence of water and could be crystallized from aqueous dichloromethane. In all cases, 2‐(1‐aziridinyl)ethanol is coordinating as bidentate chelate ligand by the nitrogen and oxygen atom of the aziridinyl and hydroxy moiety. After purification, the compounds have been fully characterized using IR spectroscopy and FAB⁺‐MS. The single‐crystal X‐ray structure analysis revealed a distorted octahedral geometry for all complexes with either trans ( 4 ) or cis ( 5 , 6 ) configuration.     

Palladium‐Catalyzed Oxidative C≡C Triple Bond Cleavage of 2‐Alkynyl Carbonyl Compounds Toward 1,2‐Dicarbonyl Compounds†

A new, general palladium‐catalyzed oxidative strategy for the cleavage of the C≡C triple bond is presented. By employing PdCl₂, CuBr₂, TEMPO and air as the catalytic system and H₂O as the carbonyl oxygen atom source, a wide range of 2‐alkynyl carbonyl compounds, including 1,3‐disubstituted prop‐2‐yn‐1‐ones, propiolamides and propiolates, lost an alkynyl carbon to access various 1,2‐dicarbonyl compounds, e.g., 1,2‐diones, 2‐keto amides and 2‐keto esters, through Wacker oxidation, intramolecular cyclization and C—C bond cleavage cascades.     

Vielseitige Koordinationschemie von Vanadium(V): Substitutionsreaktionen,Umlagerungen und Kondensationsreaktionen von Oxovanadium(V)‐Komplexen des tripodalen Sauerstoffliganden LOMe− = [η5‐(C5H5)Co{P(OMe)2(O)}3]−

Multifaceted Coordination Chemistry of Vanadium(V): Substitution, Rearrangement Reactions, and Condensation Reactions of Oxovanadium(V) Complexes of the Tripodal Oxygen Ligand L_OMe^? = [η⁵‐(C₅H₅)Co{P(OMe)₂(O)}₃]^? The octahedral oxovanadium(V) complex [V(O)F₂L_OMe] of the tripodal oxygen ligand L_OMe^? = [η⁵‐(C₅H₅)Co{P(OMe)₂(O)}₃]^? reacts with alcohols and phenol with substitution of one fluoride ligand to form alkoxo complexes [V(O)F(OR)L_OMe], R = Me, Et, i‐Prop, Ph. In the presence of water, however, both fluoride ions are substituted and a complex with the composition VO₂L_OMe can be isolated. The crystal structure shows that the oxo‐bridged trimer [{V(O)(L_OMe)O}₃] was synthesized. In the presence of BF₃ the fluoride ligand in the alkoxo‐complex [V(O)F(OEt)L_OMe] can be exchanged for pyridine to yield [V(O)(OEt)pyL_OMe]BF₄. Analogous attempts to exchange the fluoride ligand for tetrahydrofuran and acetonitrile induces a rearrangement reaction that leads to the vanadium complex [V(O)(L_OMe)₂]BF₄. The crystal structure of this compound has been determined. Its ¹H and ³¹P‐NMR spectra show that it is a highly fluxional vanadium complex at ambient temperature in solution. The two tripodal ligands L_OMe^? coordinate the vanadium centre as bidentate or tridentate ligands. The exchange bidentate/tridentate becomes slow on the NMR time scale below about 200 K.     

Palladium(II) Complexes with the Mixed‐Donor Ligand CH3S‐(CH2)3‐PPh2 Crystal Structures of [PdCl2{CH3S‐(CH2)3‐PPh2}n](n = 1, 2)

The phosphorus‐sulfur ligand 1‐(methylthio)‐3‐(diphenylphosphino)‐propane (S‐P3) has been synthesized and characterized by ¹H NMR and ¹³C NMR. Reactions of S‐P3 with [PdCl₂(PhCN)₂] afforded the complexes [PdCl₂(S‐P3)] ( I ) and [PdCl₂(S‐P3)₂] ( II ), in which S‐P3 acts as a bidentate and monodentate ligand, respectively. Compound I crystallizes in monoclinic space group P2₁/n (No. 14) with cell dimensions: a = 8.589(3), b = 15.051(3), c = 17.100(3)Å, β = 102.91(2)°, V = 2154.7(9)ų, Z = 4. Likewise, compound II crystallizes in monoclinic space group P2₁/n (No. 14) with a = 9.993(5), b = 8.613(4), c = 18.721(5)Å, β = 90.18(3)°, V = 1611.3(12)ų, Z = 2. Compound II has a trans square planar configuration with only the P‐site of the ligand bonded to the palladium atom.     

Crystal Structure of Di[(μ‐benzoato‐O,O′)bis(η5‐methylcylopentadienyl)ytterbium(III)]

Transparent orange‐red crystals of [Yb(MeCp)₂(O₂CPh)]₂ obtained by oxidation of Yb(MeCp)₂ with Tl(O₂CPh) in tetrahydrofuran have a dimeric structure with bridging bidentate (O,O′)‐benzoate groups and eight‐coordinate ytterbium.     

Disentangling steric and electronic factors in monomeric bis(2‐bromo‐4‐chloro‐6‐{[(2‐hydroxyethyl)imino]methyl}phenolato‐κ2N,O)copper(II)

The title compound, [Cu(C₉H₈BrClNO₂)₂], is a square‐planar complex. The potentially tridentate dibasic 2‐bromo‐4‐chloro‐6‐{[(2‐hydroxyethyl)imino]methyl}phenolate ligand coordinates in a trans‐bis fashion to the Cu^II centre via the imine N and phenolate O atoms. The Cu^II atom lies on the centre of inversion of the molecule. The potentially coordinating hydroxyethyl group remains protonated and uncoordinated, taking part in intermolecular hydrogen bonds with vicinal groups, leading to the formation of a two‐dimensional hydrogen‐bond network with sheets parallel to the (10) plane. Substituent effects on the crystal packing and coordination modes of the ligand are discussed.     

Neue Halogenochalkogen(IV)‐Säuren: [H3O(Benzo‐18‐Krone‐6)]2[Te2Br10] und [H5O2(Dibenzo‐24‐Krone‐8)]2[Te2Br10]

Novel Halogenochalcogeno(IV) Acids: [H₃O(Benzo‐18‐Crown‐6)]₂[Te₂Br₁₀] and [H₅O₂(Dibenzo‐24‐Crown‐8)]₂[Te₂Br₁₀] Systematic studies on halogenochalcogeno(IV) acids containing tellurium and bromine led to the new crystalline phases [H₃O(Benzo‐18‐Crown‐6)]₂[Te₂Br₁₀] ( 1 ) and [H₅O₂(Dibenzo‐24‐Crown‐8)]₂[Te₂Br₁₀] ( 2 ). The [Te₂Br₁₀]^2‐ anions consists of two edge‐sharing distorted TeBr₆ octahedra, the oxonium cations are stabilized by crownether. ( 1 ) crystallizes in the monoclinic space group P2₁/n with a = 14.520(5) Å, b = 22.259(6) Å, c = 16.053(5) Å, β = 97.76(3)° and Z = 4, whereas ( 2 ) crystallizes in the triclinic space group with a = 11.005(4) Å, b = 12.103(5) Å, c = 14.951(6) Å, α = 71.61(3)°, β = 69.17(3)°, γ = 68.40(3)° and Z = 1.     

[{(C7H13N2)AlCl}2O]: Ein zweikerniger Vinamidin‐Komplex des Aluminiums mit linearer Sauerstoffbrücke [1]

[{(C₇H₁₃N₂)AlCl}₂O]: A Dinuclear Vinamidine Aluminum Complex with a Linear Oxygen Bridge [1] [(C₇H₁₃N₂)AlCl₂] ( 1 ) reacts with Ag₂O in the ratio 2/1 to give the dinuclear vinamidine complex [{(C₇H₁₃N₂)AlCl}₂O] ( 2 ) in good yield. The crystal structure investigation of 2 reveals the presence of a linear fragment Al—O—Al in the centrosymmetric space group P2₁/c.     

The three‐dimensional coordination polymer poly[[aqua[μ4‐2,2′‐(diazene‐1,2‐diyl)dibenzoato]lead(II)] 1,2‐bis(pyridin‐4‐yl)ethylene hemisolvate]

A novel three‐dimensional coordination polymer, {[Pb(C₁₄H₈N₂O₄)(H₂O)]·0.5C₁₂H₁₀N₂}_n, has been synthesized by hydrothermal reaction of Pb(OAc)₂·3H₂O (OAc is acetate), 2,2′‐(diazene‐1,2‐diyl)dibenzoic acid (H₂L) and 1,2‐bis(pyridin‐4‐yl)ethylene (bpe). The asymmetric unit contains a crystallographically independent Pb^II cation, one L²⁻ ligand, an aqua ligand and half a bpe molecule. Each Pb^II centre is seven‐coordinated by six O atoms of bridging–chelating carboxylate groups from L²⁻ ligands and by one O atom from a coordinated water molecule. The Pb^II cations are bridged by L²⁻ ligands, forming [PbO₂]_n chains along the a axis. These chains are further connected by L²⁻ ligands along the b and c axes to give a three‐dimensional framework with a 4¹²6³ topology. The channel voids are occupied by bpe molecules.     

A new route for the synthesis of phosphate esters: 2,2′‐[benzene‐1,2‐diylbis(oxy)]bis(5,5‐dimethyl‐1,3,2‐dioxaphosphinane) 2,2′‐dioxide

Podand‐type ligands are an interesting class of acyclic ligands which can form host–guest complexes with many transition metals and can undergo conformational changes. Organic phosphates are components of many biological molecules. A new route for the synthesis of phosphate esters with a retained six‐membered ring has been used to prepare 2,2′‐[benzene‐1,2‐diylbis(oxy)]bis(5,5‐dimethyl‐1,3,2‐dioxaphosphinane) 2,2′‐dioxide, C₆H₄{O[cyclo‐P(O)OCH₂CMe₂CH₂O]}₂ or C₁₆H₂₄O₈P₂, (1), 2‐[(2′‐hydroxybiphenyl‐2‐yl)oxy]‐5,5‐dimethyl‐1,3,2‐dioxaphosphinane 2‐oxide, [cyclo‐P(O)OCH₂CMe₂CH₂O](2,2′‐OC₆H₄–C₆H₄OH), (2), and oxybis(5,5‐dimethyl‐1,3,2‐dioxaphosphinane) 2,2′‐dioxide, O[cyclo‐P(O)OCH₂CMe₂CH₂O]₂, (3). Compound (1) is novel, whereas the results for compounds (2) and (3) have been reported previously, but we record here our results for compound (3), which we find are more precise and accurate than those currently reported in the literature. In (1), two cyclo‐P(O)OCH₂CMe₂CH₂O groups are linked through a catechol group. The conformations about the two catechol O atoms are quite different, viz. one C—C—O—P torsion angle is −169.11 (11)° and indicates a trans arrangement, whereas the other C—C—O—P torsion angle is 92.48 (16)°, showing a gauche conformation. Both six‐membered POCCCO rings have good chair‐shape conformations. In both the trans and gauche conformations, the catechol O atoms are in the axial sites and the short P=O bonds are equatorially bound.     

N,N′‐Bis(Salicylidene)‐1,2‐Cyclohexanediamine Lanthanide(III) Coordination Polymers: Syntheses,Crystal Structures,and Luminescence Properties

The salen‐type ligand H₂L [H₂L = N,N′‐bis(salicylidene)‐1,2‐cyclohexanediamine] was utilized for the synthesis of two lanthanide(III) coordination polymers [LnH₂L(NO₃)₃MeOH]_n [Ln = Eu ( 1 ) and Ln = Lu ( 2 )]. The single‐crystal X‐ray diffraction analyses of 1 and 2 revealed that they are isomorphous and exhibit one‐dimension neutral structure, in which H₂L effectively functions as a bridging ligand and give rise to a chain‐like polymer. The luminescent properties of polymers in solid state and in solution were investigated and 1 exhibits typical red luminescence of Eu^III ions in solid state and dichloromethane solution and 2 emits the ligand‐centered blue luminescence. The energy transfer mechanisms in these luminescent lanthanide polymers were described through calculation of the lowest triplet level of ligand H₂L.