A Comparative Study of (Poly)ether Adducts of Alkaline Earth Iodides – An Overview Including New Compounds

New homoligand and mixed‐ligand adducts of the heavier alkaline earth metal (Ca, Sr, Ba) halides with oxygen‐donor polyether ligands have been isolated and characterized and are compared with previously obtained compounds of the same class in order to give an overview on structures and properties. Homoligand halide adducts, discussed herein, are [CaI(DME)₃]I ( 1 ), trans‐[SrI₂(DME)₃] ( 2 ), trans‐[BaI₂(DME)₃] ( 3 ), (DME = ethylene glycol dimethyl ether), [CaI(diglyme)₂]I ( 4 ), cis‐[SrI₂(diglyme)₂] ( 5 ), trans‐[BaI₂(diglyme)₂] ( 6 ),(diglyme = diethylene glycol dimethyl ether, [SrI(triglyme)₂]I ( 7 ), and [BaI(triglyme)₂]I ( 8 ), (triglyme = triethylene glycol dimethyl ether). Introduction of the mono‐coordinating THF ligand (THF = tetrahydrofuran) in the coordination sphere of 1 , 2 , 3 , 4 allows the formation of the new mixed‐ligand compounds trans‐[CaI₂(DME)₂(THF)] ( 9 ), trans‐[SrI₂(DME)₂(THF)] ( 10 ), trans‐[BaI₂(DME)₂(THF)₂] ( 11 ), and trans‐[CaI₂(diglyme)₂(THF)₂] ( 12 ). These compounds were obtained from the metal halide salts in solution with pure or mixtures of ether solvents. While compounds 1 – 8 appear to be very stable and non‐reactive, adducts 9 – 12 present a comparable reactivity to the well known THF adducts [MI₂(thf)_n] (M = Ca, n = 4; Sr, Ba, n = 5).     

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.     

Siloxyaluminate and Siloxygallate Complexes as Models for Framework and Partially Hydrolyzed Framework Sites in Zeolites and Zeotypes

Anionic molecular models for nonhydrolyzed and partially hydrolyzed aluminum and gallium framework sites on silica, M[OSi(OtBu)₃]₄⁻ and HOM[OSi(OtBu)₃]₃⁻ (where M=Al or Ga), were synthesized from anionic chlorides Li{M[OSi(OtBu)₃]₃Cl} in salt metathesis reactions. Sequestration of lithium cations with [12]crown-4 afforded charge-separated ion pairs composed of monomeric anions M[OSi(OtBu)₃]₄⁻ with outer-sphere [([12]crown-4)₂Li]⁺ cations, and hydroxides {HOM[OSi(OtBu)₃]₃} with pendant [([12]crown-4)Li]⁺ cations. These molecular models were characterized by single-crystal X-ray diffraction, vibrational spectroscopy, mass spectrometry and NMR spectroscopy. Upon treatment of monomeric [([12]crown-4)Li]{HOM[OSi(OtBu)₃]₃} complexes with benzyl alcohol, benzyloxide complexes were formed, modeling a possible pathway for the formation of active sites for Meerwin–Ponndorf–Verley (MPV) transfer hydrogenations with Al/Ga-doped silica catalysts.     

Preparation, structural characterisation, and magnetic properties of [Cu(men)2][Cu2Cd2Cl2(CN)6] (men = N-methylethane-1,2-diamine)

The novel complex [Cu(men)₂][Cu₂Cd₂Cl₂(CN)₆] (I) was isolated from the aqueous-ethanol system containing CuCl₂, men (men = N-methylethane-1,2-diamine) and K₂[Cd(CN)₄] in the presence of dilute hydrochloric acid and chemically and spectroscopically characterised. The crystal structure of I consists of [Cu ₂ ^I (CN)₆] and [Cd₂Cl₂(CN)₆] building units bridged by cyanide ligands and forms a three-dimensional skeleton with cavities. [Cu(men)₂]²⁺ cations in which two men ligands are chelated (mean Cu-N is 2.033(6) Å) are located in the cavities. The coordination polyhedron around the Cu(II) atoms is formed as a tetragonal bipyramidal by two weaker axial Cu-Cl bonds (2.8642(12) Å) with chlorido ligands from the skeleton. The Cu(I) and Cd(II) atoms in the skeleton exhibit tetra-(CuC₄ chromophore) and penta-coordination (CdN₃Cl₂), respectively. The temperature-dependent susceptibility measurements indicate a Curie-Weiss-like behaviour and the presence of weak anti-ferromagnetic interaction.     

Die Quecksilber(II)-Ionen induzierte Hydrolyse gemischter Hexahalogenoosmate(IV)

Mercury(II)-Induced Hydrolysis of Mixed Hexahalo-Osmates(IV) The strong hydrolytic activity of Hg²⁺ ions on complexes [OsX_nI_6?n]^2?, X = Cl or Br; n = 1 – 5, is due to electrophilic attack at the I ligands. Small amounts of Hg²⁺ remove only one I. The very stable [HgI]⁺ and [HgI₂] are formed along with the corresponding pentahalo-monaquo-osmates(IV). In cis-[OsCl₄I₂]^2? and fac-[OsCl₃I₃]^2? ligands rearrange during hydrolysis giving the thermodynamically favoured I? Os? H₂O axis. Other mono- and bivalent cations have only a slight catalytic effect on the aquation, increasing with the size from Mg²⁺ to Ba²⁺.     

Synthesis and Complexation of 1,2-Bis[(monoaza[15]crown-5)-N-yl]glyoxime. Crystal Structure of (1,2-Bis[(monoaza[15]crown-5)-N-yl]glyoximato)palladium(II)

A new vicinal dioxime ligand with two crown-ether groups, 1,2-bis[(monoaza[15]crown-5)-N-Yl]-glyoxime(LH₂), has been prepared from cyanogen di-N-oxide and monoaza[15]crown-5. Ni(II), Pd(II), and Pt(IV) complexes of LH₂ with or without alkali-metal ions bound to macrocyclic groups have been isolated. The high affinity of [Pd(LH)₂] and [Ni(LH)₂] for the K⁺ ion is observed in solvent extraction experiments. A single-crystal X-ray structure confirms the postulated geometry of [Pd(LH)₂]- The Pd-atom of the centro-symmetric molecule has square-planar PdN₄ coordination where Pd–N distances range from 1.978(3) to 1.970(3) Å. The N–Pd–N intraligand angle is 79.9(1)^°.     

A mixed‐valence chair‐like tetranuclear copper(I,II) cluster with three linking modes of the 3,5‐bis(2‐pyridyl)‐1,2,4‐triazole ligand

In the tetranuclear copper complex tetrakis[μ‐3,5‐bis(2‐pyridyl)‐1,2,4‐triazolido]bis[3,5‐bis(2‐pyridyl)‐1,2,4‐triazolido]dicopper(I)dicopper(II) dihydrate, [Cu^I₂Cu^II₂(C₁₂H₈N₅)₆]·2H₂O, the asymmetric unit is composed of one Cu^I center, one Cu^II center, three anionic 3,5‐bis(2‐pyridyl)‐1,2,4‐triazole (2‐BPT) ligands and one solvent water molecule. The Cu^I and Cu^II centers exhibit [Cu^IN₄] tetrahedral and [Cu^IIN₆] octahedral coordination environments, respectively. The three independent 2‐BPT ligands adopt different chelating modes, which link the copper centers to generate a chair‐like tetranuclear metallomacrocycle with metal–metal distances of about 4.4 × 6.2 Å disposed about a crystallographic inversion center. Furthermore, strong π–π stacking interactions and O—H...N hydrogen‐bonding systems link the tetracopper clusters into a two‐dimensional supramolecular network.     

A twofold interwoven two‐dimensional→two‐dimensional (2‐D→2‐D) cluster–organic network based on the [Cu2I2] cluster and the 4,4′‐(diazenediyl)dipyridine ligand: poly[[μ2‐4,4′‐(diazenediyl)dipyridine]‐μ2‐iodido‐copper(I)]

In the polymeric title compound, [CuI(C₁₀H₈N₄)]_n, the Cu^I atom is in a four‐coordinated tetrahedral geometry, formed by two I atoms and two pyridine N atoms from two different 4,4′‐(diazenediyl)dipyridine (4,4′‐azpy) ligands. Two μ₂‐I atoms link two Cu^I atoms to form a planar rhomboid [Cu₂I₂] cluster located on an inversion centre, where the distance between two Cu^I atoms is 2.7781 (15) Å and the Cu—I bond lengths are 2.6290 (13) and 2.7495 (15) Å. The bridging 4,4′‐azpy ligands connect the [Cu₂I₂] clusters into a two‐dimensional (2‐D) double‐layered grid‐like network [parallel to the (10) plane], with a (4,4)‐connected topology. Two 2‐D grid‐like networks interweave each other by long 4,4′‐azpy bridging ligands to form a dense 2‐D double‐layered network. To the best of our knowledge, this interwoven 2‐D→2‐D network is observed for the first time in [Cu₂I₂]–organic compounds.     

Syntheses,Characterization, and Crystal Structures of a Dinuclear Complex and Coordination Polymer of Mercury(II) with Schiff Base Ligands containing N3 and N4 Donors

Two dinuclear mercury(II) iodide compounds, [Hg₂(L)(I)₄] ( 1 ) and [(L′)Hg(μ‐I)₂HgI₂]_n ( 2 ) [L = N,N′‐bis(phenyl(pyridin‐2‐yl)methylene)propane‐1,2‐diamine and L′ = N‐(phenyl(pyridin‐2‐yl)methylene)propane‐1,2‐diamine] were synthesized and characterized. The molecular structures of [Hg₂(L)(I)₄] ( 1 ) and [(L′)Hg(μ‐I)₂HgI₂]_n ( 2 ), which were determined by single‐crystal X‐ray diffraction, indicate that each Hg^II in 1 has a distorted tetrahedral environment around the metal atom with a HgN₂I₂ chromophore, whereas in 2 one mercury(II) atom adopts a distorted tetrahedral arrangement with a HgI₄ chromophore and the other has a distorted square pyramidal environment with HgN₃I₂ chromophore. In the solid state, compound 2 consists of a 1D coordination polymer structure.     

In situ assembly of a host–guest linked,mixed valence copper(II)–copper(I) coordination polymer [Cu(1,2-en)2(μ3-I)2Cu2(μ2-I)2]n via partial reduction of copper(II) under ambient conditions

A 2-D coordination polymer, [Cu(1,2-en)₂(μ₃-I)₂Cu₂(μ₂-I)₂]_n (1), was formed at room temperature by in situ insertion of [Cu(1,2-en)₂]²⁺ guests into 1-D chains of a [Cu₂I₄]^2? host [1,2-en?=?1,2-diaminoethane]. The structure of the complex was confirmed by single-crystal X-ray diffraction study. The shortest copper(I)–copper(I) distance within the complex is 2.89?Å.     

Regioselective intramolecular bridging of p-tert-butylcalix[10]arene

The synthesis and characterization of a series of regioselective intramolecular bridging of calix[10]arene are described for the first time. Reacting p-tert-butylcalix[10]arene with tri-ethylene glycol ditosylate using K₂CO₃ as a base in toluene, 1,2-calix[10]crown-4 2a, 1,4-calix[10]crown-4 2b and 1,6-calix[10]crown-4 2c were obtained in yields of 9%, 14% and 7%, respectively. While using Cs₂CO₃/acetone instead of K₂CO₃/toluene, the 1,4-calix[10]crown-4 2b was obtained selectively in good yield up to 50%.     

Two [Cu2I2]‐based coordination polymers of 1,3‐bis(pyridin‐4‐yl)propane

Solvothermal reactions of Cu₂(OH)₂CO₃ with 1,3‐bis(pyridin‐4‐yl)propane (bpp) in the presence of aqueous ammonia in 4‐iodotoluene/CH₃CN or 1,4‐diiodobenzene/CH₃CN afforded two [Cu₂I₂]‐based coordination polymers, namely catena‐poly[[[di‐μ‐iodido‐dicopper(I)]‐bis[μ‐1,3‐bis(pyridin‐4‐yl)propane‐κ²N:N′]] p‐toluidine tetrasolvate], {[Cu₂I₂(C₁₃H₁₄N₂)₂]·4C₇H₉N}_n, (I), and the analogous 1,4‐diiodobenzene monosolvate, {[Cu₂I₂(C₁₃H₁₄N₂)₂]·C₆H₄I₂}_n, (II). The [Cu₂I₂] unit of (I) lies on a centre of symmetry at the mid‐point of the two I atoms, while that of (II) has a twofold axis running through the I...I line. In (I) and (II), each Cu centre is tetrahedrally coordinated by two μ‐I and two N atoms from two different bpp ligands. Each rhomboid [Cu₂I₂] unit can be considered as a four‐connecting node linked to the symmetry‐related [Cu₂I₂] units via two pairs of bpp ligands to form a one‐dimensional double chain along the c axis. The dimensions of the [Cu₂I₂(bpp)₂]₂ rings in (I) and (II) are different, which may be due to the presence of different guest solvent molecules in the structures. In (I), one p‐toluidine molecule, derived from an Ullmann coupling reaction of 4‐iodotoluene with ammonia, interacts with the [Cu₂I₂] cluster fragment through N—H...I hydrogen bonds, while the two p‐toluidine molecules interact via N—H...N hydrogen bonds. In (II), two I atoms of each 1,4‐diiodobenzene molecule are linked to the I atoms of the [Cu₂I₂] fragments from a neighbouring chain via I...I secondary interactions.     

The Synthesis of Dibenzo[3n]crown-n by Novel Methods and their Cation Binding Studied by Fluorescence Spectroscopy. Part IV

The dibenzo[3n]crown-n were synthesised from1,2-bis(o-hydroxyphenoxy)ethane obtained from 1,2-bis(o-formylphenoxy)ethane via Bayer-Willigeroxidations with H₂O₂/CH₃COOH in good yields. The cyclic condensation of 1,2-bis(o-hydroxyphenoxy)ethanewith dichlorides, and ditosylates of polyethylene glycols in DMF/Me₂CO₃ gave the macrocyclesdibenzo[15]crown-5, dibenzo[18]crown-6, dibenzo[21]crown-7 anddibenzo[24]crown-8. The structures were identified using IR, mass, ¹H and ¹³C NMR spectroscopy. Therecognition of the molecules for the cations, Li⁺, Na⁺, K⁺, Rb⁺ and Zn²⁺were conducted quantitatively with steady state fluorescencespectroscopy. The 1:1 association constants in acetonitrileshowed a good relation of the appropriate size of the macrocyclic ether towards the fitting cationradii. Namely, dibenzo[15]crown-5 was the best for Li⁺ binding and more than 100 times better thanNa⁺ and K⁺. Dibenzo[21]crown-7 was excellent for Rb⁺ binding while K⁺ is 100 timesless preferred. The largest crown ether studied, dibenzo[24]crown-8, exhibited the order of binding power,Rb⁺ > K⁺ > Na⁺. Zn²⁺ displayed, however, a marked binding with only dibenzo[18]crown-6.p>     

Structural and Spectroscopic Studies of Halocuprate(I) and Haloargentate(I) Complexes [M2XnX′4−n]2−

The complexes [Cu₂Br₄]^2?, [Cu₂I₄]^2?, [Cu₂I₂Br₂]^2?, [Cu₂I₃Cl]^2?, [Ag₂Cl₄]^2? have been characterized as their isomorphous bis(triphenylphosphoranylidene)ammonium ([Ph₃PNPPh₃]⁺ = PNP⁺) salts by single crystal structural determinations. All anions show the centrosymmetric doubly halogen‐bridged forms [XM(μ‐X)₂MX]^2? with three‐coordinate metal atoms that have been observed in [M₂X₄]^2? complexes with other large organic cations. In [Cu₂I₂Br₂]^2? the iodide ligands occupy the bridging positions and the bromide the terminal positions, while in [Cu₂I₃Cl]^2?, obtained in an attempt to prepare [Cu₂I₂Cl₂]^2?, two of the iodide ligands occupy the bridging positions with the third iodide and the chloride ligand occupying two statistically disordered terminal positions. In [Ag₂Cl₄]^2? the distortion from ideal trigonal coordination of the metal atom is greater than in the copper complexes, but less than in other previously reported [Ag₂Cl₄]^2? complexes with organic cations. The ν(MX) bands have been assigned in the far‐IR spectra, and confirm previous observations regarding the unexpectedly simple IR spectra of [Cu₂X₄]^2? complexes.     

Eu(fod)(3) binding on the (1)H-NMR spectra of some benzo[3n]crown-n and dibenzo[3n+2]crown-n

The complexing of Eu(fod)₃ with macrocyclic ethers, benzo[15]crown-5, benzo[12]crown-4, dibenzo[20]crown-6, dibenzo[23]crown-7 and dibenzo[26]crown-8 was observed on their ¹H-NMR spectra and the selective binding constants at 400 MHz and 305 K in CDCl₃ were reported. The Eu(fod)₃ interaction displayed the selective binding role of oxygen on macrocyclic, H₂COCH₂, backbones with o- or m-dioxyphenyl groups referring the ¹H chemical shifts. The estimated equilibrium constants, K_a of 1:1 ratio of interactions were in accordance with the Eu³⁺ ionic radii to bind the oxygen sites depending on the macrocyclic size and conformation of the ethers. The minimum lanthanide-macrocyclic ether distance displayed the maximum stability so that benzo[3n]crown-n (n=4, 5) group was found to bind the Eu(fod)₃ moderately whilst dibenzo[3n+2]crown-n (n=6-8) oligomer chemical shifts were induced largely since the such Eu³⁺ complexes are more stable with larger ethyleneoxy groups.     

1,3-Alternate and C-1,2-Alternate Tetrahomodioxacalix[4]crowns. Crystal Structures and Metal Ion Complexation

Two novel tetrahomodioxacalix[4]crowns with crown-5 and crown-6 rings weresynthesized. From X-ray crystal structures, homooxacalix[4]crown-5 (3) andhomooxacalix[4]crown-6 (2) were found to be in the 1,3-alternate and theC-1,2-alternate conformations, respectively. Homooxacalix[4]crown-5 (1)shows a marked selectivity for cesium ion over other metal ions tested.     

Heterometallic cyanide-bridged complexes containing RhRuRh triad: NMR data on exchange reactions and ligand effect transmission

Trans-[RuPy₄(CN)₂ cleaves chloro-rhodium bridges in rhodium(I) binuclear complexes, [Rh(CO)₂Cl]₂, [Rh(Cod)Cl]₂, and [(Cod)RhCl₂Rh(CO)₂] yielding heterometallic triad complexes, [(CO)₂ClRh(NC)RuPy₄(CN)RhCl(CO)₂] (I), [(Cod)ClRh(NC)RuPy₄(CN)RhCl(Cod)] (II), and [(Cod)ClRh(NC)RuPy₄(CN)RhCl(CO)₂] (III), respectively. In solutions, III coexists with equilibrium amounts of I and II in the near-binomial proportions. Under action of [Rh(CO)₂Cl]₂, II transforms into I with parallel formation of [Rh(Cod)Cl]₂. Ligand effect transmission along the L-Rh-NC-Ru-CN-Rh-L′ chain is studied by ¹H and ¹³C NMR. Chemical shifts δ¹H and δ¹³C of Ru-bound Py ligands are sensitive to the nature of Rh-bound ligands. Values of δ¹H and δ¹³C of Cod and ¹³C of CO ligands are sensitive to the ligands at the remote end of the L-Rh-NC-Ru-CN-Rh-L′ chain. Reaction of trans-[RuPy₄(CN)₂] with Rh₂(OAc)₄ yields an apparently linear polymer [-Rh(OAc)₄Rh-NCRuPy₄CN-]. Upon action of [Rh(CO)₂Cl]₂, the polymer decomposes yielding I and Rh₂(OAc)₄. X-ray structure data for I are given.     

Crystal structures of triphenylamylphosphonium iodide [Ph<Subscript>3</Subscript>AmP]I and triphenylamylphosphonium tetraiodide [Ph<Subscript>3</Subscript>AmP]I<Subscript>4</Subscript>

By reaction of triphenylamylphosphonium iodide [Ph₃AmP]I (I) with antimony iodide in acetone, triphenylamylphosphonium tetraiodide [Ph₃AmP]₂I₄ (II) was synthesized. Crystals of I consist of triphenylamylphosphonium cations and iodine anions. Compound II contains two types of tetrahedral triphenylamylphosphonium cations, iodine anions, and [I₃]^? anions. Atoms P have a distorted tetrahedral coordination in cations I and II (the CPC angles are 106.48(12)°–111.25(12)° in I and 107.05(9)°–112.62(10)° in II). The centrosymmetric trinuclear [I₃]^? anion in II is nearly linear (the I(2)I(1)I(3) angle is 178.65°, the I(1)–I(2) and I(1)–I(3) bond lengths are 2.8925(2) Å and 2.9281(2) Å, respectively).     

μ-Amido complexes of ruthenium carbonyl. Asymmetric versus symmetric bridging preference of the monodeprotonated derivatives of 1,2-arenediamines. Crystal structure of [Ru3(μ-H)(μ-H3N2-4,5-Me2-1,2-phenylene)]

[Ru₃(CO)₁₂] reacts with 1,2-arenediamines (H₄N₂arene), under CO, to give the very asymmetric clusters [Ru₃(μ-H)(μ-H₃N₂arene)(CO)₉] (arene = 1,2-phenylene (1a) or 4,5-Me₂-1,2-phenylene (1b)) in which the three Ru atoms bear two, three, and four CO ligands, respectively. Under similar conditions, reaction of [Ru₃(CO)₁₂] with 1,8-diaminonaphthalene (H₄N₂naph) leads to break up of the cluster framework to give the binuclear ruthenium(I) compound [Ru₂(μ-H₂N₂naph)(CO)₆] (3). The crystal structure of compound 1b has been determined by an X-ray diffraction study.     

Synthesis and properties of some tetracyclic derivatives of 9H-carbazole, 10,11-dihydro-5H-dibenz[b,f]azepine,and 5,11-dihydrodibenz[b,e] [1,4]oxazepine

The behavior of 5,6-dihydro-4H-pyrido[3,2,1-jk]carbazol-4-one (10) , 1,2,7,8-tetrahydro-3H-quino[1,8-ab][1]benzazepin-3-one (11) , 1,2-dihydro-9H-[1]benzazepino[1,9-ab] [4,1]benzoxazepin-4 (3H)one (13) , and 1,2-dihydro-8H-[1]benzazepino[1,9-cd] [1,5]benzoxazepin-4(3H)one (14) towards the Schmidt reaction has been determined in polyphosphoric acid and in benzeneor chloroform-sulfuric acid. Evidence for the structure of the new heterocyclic systems obtained from these four compounds is presented.