EPR‐spektroskopische Charakterisierung (X‐, Q‐Band) monomerer AgII‐ und AuII‐Komplexe der Thiakronenether [12]anS4, [16]anS4, [18]anS6 und [27]anS9

EPR Spectroscopic Characterization (X‐, Q‐Band) of Monomeric Ag^II‐ and Au^II‐Complexes of the Thiacrownethers [12]aneS₄, [16]aneS₄, [18]aneS₆ and [27]aneS₉ The reaction of the prepared Ag^I complexes of the thiacrownethers [12]aneS₄, [16]aneS₄, [18]aneS₆ and [27]aneS₉ with c. H₂SO₄ as well as the reaction of [Au^IIICl₄]^‐ with [18]aneS₆ and [27]aneS₉ leads to labile Ag^II‐ (4d⁹, ^{107, 109}Ag: I=1/2) and Au^II‐ (5d⁹, ¹⁹⁷Au: I=3/2) thiacrownether complexes, respectively, which were characterized by X‐ and Q‐band EPR. The EPR spectra of [Ag^II([12]anS₄)]²⁺ and [Ag^II([18]anS₆)]²⁺ were reinvestigated. According to an analysis of the spin‐density distribution only 20 ‐ 25 % is located on the Ag or Au atoms. Most of the spin‐density was found to be on the S donor atoms of the thiacrownethers. The high delocalization of the spin‐density leads certainly to a noticeable reduction of the Ag^I/Ag^II redox potential and is considered as being mainly responsible for the easy accessibility of the Ag^II compounds.     

Influence of the Coordination of Donor Solvent Molecules to 1,4,7,10-Tetramethyl-1,4,7,10- tetraazacyclododecanenickel(II) and Analogous Nickel(II) Complexes on Their Steric Factors

Coordination equilibrium constants (K _NiS) of some donor solvent molecules to 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecanenickel(II) ([Ni(Me₄[12]aneN₄)]²⁺) were determined in nitrobenzene (a noncoordinating bulk solvent). The first (K _NiS1) and second stepwise coordination equilibrium constants (K _NiS2) for 1,4,7,10-tetraazacyclododecanenickel(II) ([Ni([12]aneN₄)]²⁺), 1,4,8,11-tetraazac yclotetradecane- nickel(II) ([Ni([14] aneN₄)]²⁺), 1,4,8,11-tetrathiacyclotetra-decanenickel(II) ([Ni([14]aneS₄)]²⁺) were also reinvestigated. The K _NiS values for [Ni(Me₄[12]aneN₄)]²⁺ were compared to those of [Ni([12]aneN₄)]²⁺, (1R,4S, 8R,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II) (R,S,R,S-[Ni(Me₄[14]aneN₄)]²⁺), R,R,S,S-[Ni(Me₄[14]aneN₄)]²⁺, [Ni([14]aneN₄)]²⁺, and [Ni([14]aneS₄)]²⁺. Coordination of pyridine (Py), N,N,N′,N′-tetramethylurea (TMU), and N,N-dimethylacetamide (DMA) to [Ni(Me₄[12]aneN₄)]²⁺ was observed, although these donor solvent molecules did not coordinate to R,S,R,S-[Ni(Me₄[14]aneN₄)]²⁺. The K _NiS values for Py, TMU, and DMA are 7.9, 2.8, and 9.0 dm³⋅mol⁻¹, respectively. Some hydrogen-bonding waters were coordinated to R,S,R,S-[Ni(Me₄[14]aneN₄)]²⁺, but such waters did not coordinate to [Ni(Me₄[12] aneN₄)]²⁺. Also, the K _NiS2 values were larger than the corresponding K _NiS1 values for [Ni([14]aneS₄)]²⁺. Furthermore, the K _NiS1 values for [Ni([12]aneN₄)]²⁺ were the largest among these nickel(II) complex cations. The K _NiS, K _NiS1, and K _NiS2 values are discussed in terms of properties of the donor solvents and steric strains of these nickel(II) complex cations.     

Characterization and properties of the copper(II/I) complexes of macrocyclic hexathiaether ligand [21]aneS6

The copper(II/I) complexes of hexathiaether macrocyclic ligand, 1,4,8,11,15,18-hexathiacyclohenicosane ([21]aneS₆), were synthesized, and characterized by electrochemical and spectroscopic techniques. Cyclic voltammetric studies indicate that Cu([21]aneS₆)^2+/+ forms a reversible one-electron redox couple. The electrochemical potential obtained for Cu([21]aneS₆)^2+/+ (E^f = 0.89 V, against SHE) was found to be the highest potential reported to date for a Cu^2+/+ macrocyclic system in aqueous solution. By employing the Nernst equation, we can infer that the practical upper limit for formal potential of Cu(II/I)L systems maybe close to this high value. Stability constant data obtained for these complexes indicate that Cu([21]aneS₆)⁺is 12 orders of magnitude greater in stability than that of Cu([21]aneS₆)²⁺ indicating the favorable nature of this large macrocyclic ligand towards formation of Cu(I) complexes over Cu(II) complexes. Crystal structure of Cu([21]aneS₆)⁺ ( Fig. 2) shows that four sulfurs adjacent to one another are coordinated to Cu⁺ ion in this complex. Bond angles and distances calculated for the crystal indicate that it is a distorted tetrahedron, a geometry commonly encountered by Cu(I) complexes. This is the first report of synthesis and characterization of a metal coordinated [21]aneS₆ complex.     

Synthesis and extraction properties of new chromogenic azo-calix[4]dibenzothiacrown ethers

Two novel chromogenic cone calix[4]dibenzothiacrown ethers 3 and 4 in which nitrophenylazo groups attached at the phenyl ring of dibenzothiacrown unit were described. The extraction properties of 3 and 4 toward different transition metal ions have been studied using conductometric technique and found to exhibit Cu²⁺ and Hg²⁺ selectivity with very high stability constants range from log K _assoc = 5.19 to log K _assoc = 8.72.     

Spectroscopic studies and X-ray crystal structures of charge-transfer complexes of 1,4,7-trithiacyclononane with diiodine

1,4,7-Trithiacyclononane ([9]aneS₃) reacts with molecular diiodine in CH₂Cl₂ to form a 1:1 adduct. The formation constant and the thermodynamic parameters of this adduct have been determined by UV-visible spectra of several solutions at the temperatures of 15, 20, 25, 30, and 35°C. The ¹³C NMR spectra show that adducts with higher ligand/diiodine molar ratios are formed. Two neutral charge-transfer molecular compounds having formula 2[9]aneS₃ · 4I₂ ( I ) and [9]aneS₃ · 3I₂ · ( II ) have been obtained as crystals. The crystals of I are triclinic (a = 8.498(2) Å, b = 13.984(4) Å, c = 14.898(6) Å, α = 65.57(2)°, γ = 89.19(2)°, γ = 81.26(2)°, Z = 2, space group P1; R = 0.025) and contain units formed by two [9]aneS₃ molecules connected by a diiodine molecule; one [9]aneS₃ binds two other diiodine molecules, while the second binds only one other diiodine molecule. The crystals of II are monoclinic (a = 13.810(2) Å, b = 9.829(4) Å, c = 16.198(6) Å, β = 113.41(2)°, Z = 4, space group P2₁/c; R = 0.019) and contain molecules of [9]aneS₃ binding three diiodine molecules. FT-Raman spectra in the characteristic v(I–I) region, carried out on the solid adducts, are discussed in comparison with the structural parameters.     

Liquid—liquid distribution of ion associates of tetraiodopalladate(II) with quaternary ammonium counter ions

The distribution behaviour of ion association of Pdl^2?₄ with ten quaternary ammonium cations between chloroform and an aqueous phase was examined and extraction constants (log K_ex) were determined. Linear relationships between log K_ex and the number of methylene groups in the quaternary ammonium ions were observed. Quantitative extraction of palladium was achieved with Zeph⁺ or TBA⁺; the molar absorptivity was 2.5 × 10⁴ l mol^?1 cm^?1 at 344 nm. The effect of other ions on the spectrophotometric determination of palladium, based on their extraction, is reported.     

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

The dibenzo[3n]crown-n were synthesised starting from bis[2-(o-hydroxyphenoxy)ethyl]ether obtained from bis[2-(o-formylphenoxy)ethyl]ether via Baeyer-Villiger oxidation in H₂O₂/CH₃COOH in a good yield. The cyclic condensation ofbis[2-(o-hydroxyphenoxy)ethyl]etherwith tri- and tetraethylene glycol bisdichlorides andthe bisditosylate of pentaethylene glycol in DMF/Me₂CO₃ afforded the large cyclic ethers of dibenzo[21]crown-7, dibenzo[24]crown-8 and dibenzo[27]crown-9. The structures were analysed with IR, ¹H NMR, ¹³C NMR and low-resolution mass spectroscopy methods. The Na⁺, K⁺, Rb⁺ and Cs⁺ cations' recognition of the molecules were conducted withsteady-state fluorescence spectroscopy. The 1:1 association constants, K_a, in acetonitrile were estimated. Dibenzo[21]crown-7 was the best both for K⁺ and Rb⁺ binding but showed too small an effect on Cs⁺. Dibenzo[24]crown-8 exhibited the binding power in the order of Rb⁺ > K⁺ > Na⁺ > Cs⁺. However, dibenzo[27]crown-9 displayed marked binding with only K⁺ but not with Rb⁺ or with Cs⁺ cations probably due to the heavy atom effect of fluorescence quenching.     

Disordered crystal structure of 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane <Emphasis Type="Italic">bis</Emphasis>(picrate) hydrate

For 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane bis(picrate) hydrate [H₂(Crypt-222)]²⁺·2Pic^?·1.19 H₂O (I), its disordered crystal structure has been determined by X-ray diffraction (XRD) analysis. The structure of I (space group \(P\bar 1\), a = 10.662 Å, b = 12.586 Å, c = 15.342 Å, α = 107.73°, β = 102.33°, γ = 90.49°, Z = 2) was solved by direct methods and refined by full-matrix least-squares in an anisotropic approximation to R = 0.111 for all 5000 independent reflections collected (CAD-4 automatic diffractometer, CAD-4, λMoK_α). The 2.2.2-cryptand dication is disordered and has two different conformations with probabilities of 66.7% and 33.7%. In addition to one independent water molecule, the cavity of the dication has a low-probability site of another water molecule, whose occupancy is 0.19. In the two independent picrate anions, some of their NO₂ groups are disordered over two orientations. The crystal structure of I has various interionic (intermolecular) and intracation hydrogen bonds.     

Interaction between Anions and Molybdenum Allyl Dicarbonyl Complexes of 1,4,7‐Trithiacyclononane

The labile complex [MoCl(η³‐methallyl)(CO)₂(NCMe)₂] reacts with the ligand 1,4,7‐trithiacyclononane ([9]aneS₃) and the salt NaBAr′₄ to afford [Mo(η³‐methallyl)(CO)₂([9]aneS₃)][BAr′₄] ( 1?BAr′₄ ). An analogous reaction of [MoBr(η³‐allyl)(CO)₂(NCMe)₂] yields [Mo(η³‐allyl)(CO)₂([9]aneS₃)][BAr′₄] ( 2?BAr′₄ ). The new compounds 1?BAr′₄ and 2?BAr′₄ were characterized by IR and NMR spectroscopic analysis and X‐ray diffraction studies. Both compounds feature the cyclic thioether [9]aneS₃ coordinated as a tridentate ligand to the molybdenum center. The allyl ligand in 2?BAr′₄ is aligned with the middle of the OC‐Mo‐CO angle, which is acute. Both of these features are typical of most pseudo‐octahedral allyl dicarbonyl molybdenum complexes. In contrast, the allyl group is rotated in 1?BAr′₄ , which is attributed to steric hindrance between the methyl substituent and the ligated thioether, and the OC‐Mo‐CO angle is obtuse. Compound 1?BAr′₄ undergoes rapid substitution of [9]aneS₃ by either chloride and fluoride ions in dichloromethane, and the products include the known species [{Mo(η³‐methallyl)(CO)₂}₂(μ‐Cl)₃]^? and a structurally similar new anionic complex with two fluoro and one hydroxo bridging ligands, respectively. Stable supramolecular adducts were formed in the reactions of 1?BAr′₄ and 2?BAr₄ with bromide, iodide, hydrogensulfate, and methanesulfonate compounds. The binding constants of these adducts in dichloromethane were calculated from ¹H NMR spectroscopic titration data, and the solid‐state structures of the 1?Br , 1?HSO₄ , 1?I , and 2?I adducts were determined by X‐ray diffraction studies. The surprising slightly higher stability of the iodide adduct relative to that of bromide was investigated theoretically, with the results pointing to an effect of the differential solvation of the halide ions.     

Liquid ion-exchange extraction study of hexacyanoferrate(III) with trioctylmethylammonium chloride (aliquat-336)

Liquid-liquid ion-exchange extraction of various anions including hexacyanoferrate(III) with a chlorobenzene solution of trioctylmethylammonium chloride (TOMA-Cl; Aliquat-336 chloride) is described. The ion-pair extraction constant of TOMA-Cl (K^Q.Cl_ex = 10⁴) and the ion-exchange extraction constants of TOMA-Cl for each anion (K^Cl.X_ex) are reported. The order of selectivity of anion extraction is Fe(CN)^3-₆ (log K^Q.X_ex = 22.41) > ClO^-₄(8.47) > PAR^- (7.80) > I^-(7.32) > NO^-₃(5.81) > Br^-(5.34) > Cl^-(4.00).     

Solvent extraction of silver picrate by 3m-crown-m ethers (m = 5, 6) and its mono-benzo-derivative from water into benzene or chloroform: elucidation of an extraction equilibrium using component equilibrium constants

Ion-pair formation constant (K_AgPic in mol⁻¹ dm³) of silver picrate (AgPic), those (K_AgLPic) of its ion-pair complexes (AgLPic) with crown ethers (L) and complex formation constants (K_AgL) of Ag⁺ with L (15-crown-5 ether (15C5) and benzo-15C5) in water (w) were determined potentiometrically at 25 °C. Compounds used as L were 18-crown-6 ether (18C6), its benzo-derivative (B18C6) and the two 15C5 derivatives. Extraction constants (K_ex in mol⁻¹ dm³) of AgPic with L (15C5, 18C6, B18C6) from acidic w-phases into either C₆H₆ or CHCl₃ were recalculated from K_AgPic, K_AgL, K_AgLPic and data opened in previous papers. Thus obtained K_ex was divided into five component equilibrium constants containing K_AgL and K_AgLPic anew. Then, contributions of the component constants, K_AgL, K_AgLPic and distribution constants of AgLPic between the w- and C₆H₆-phases, to K_ex were discussed and compared with corresponding extraction systems of NaPic and KPic with18C6.     

Association constants of dibenzo[3n + 2]crown-n ethers using steady-state fluorescence spectroscopy

The steady-state fluorescence spectra of cation complexes of fluorophore macrocyclic ethers have been studied for the estimation of 1:1 association constants, and perchlorate salts of Li⁺, Na⁺, K⁺ Rb⁺ and Pb²⁺ complexing with dibenzo[23]crown-9, dibenzo[26]crown-10, and sym-dibenzo[26]crown-10, were investigated. The fluorescence emission maximum of the free and the various ligand/cation mixtures of complexed crown ethers were measured at room temperature in AN. The concentrations of chromophore crown ether were obtained from nonlinear calibration plots. The 1:1 stoichiometry of association constants (K_ass) were calculated using the equation, 1/K_ass [L_o] = (1 − nP)ⁿ(1 − m)^m/P with linear best fit of plots depending on 1/[L_o] where P = P_C/[1 + (m − 1)P_C] and P_C is the mole fraction of n/m ratio of the complexed ligand. The association constants of cations, K_ass, displayed the cation selectivities depending on the cation radii and the macrocyclic ether size, and Pb⁺ was found to give the strongest association with such crown ethers.     

Stable free-radical complexing reagents in applications of electron spin resonance to the determination of metals: Part 2. Spin-labelled iminooxime [1]

Possibilities for the determination of metals by means of the intensity of the e.s.r. signal of the chelate-fonning reagent, spin-labelled iminomonoxime — 4-oximinomethyl-2,2,5,5-tetramethyl-3-imidazoline-1-oxyl, have been studied. The dissociation constant of the oxime group (pK^T_a = 9.36 ± 0.08) and the reagent partition constant in the chloroform—water system (log K_D = 0.80 ± 0.11) are reported. The reagent extracts copper, cobalt and nickel into chloroform. Copper is extracted as its CuA₂, chelate (log K_D = 0.91 ± 0.03; log K_ex = -3.35 ± 0.09; log β₂, = 15.8 ± 0.2). Several properties of the spin-labelled and conventional oximes are compared. It is confirmed that a radical-containing substituent produces a strong electron-acceptor effect. Unusual extractive and e.s.r.- spectroscopic behaviour of cobalt is indicated; an adduct of the spin-labelled chelate with atmospheric oxygen seems to be formed. Methods for the determination of cobalt and nickel based on the extraction with spin-labelled oxime into chloroform and subsequent separation of the excess of reagent on a chromatographic column are described. The detection limits are 3 × 10^-7 M for cobalt and 10^-6 M for nickel.     

Solvent extraction and self-assembly of nanosized aggregates of p-tert-butyl thiacalix[4]arenes tetrasubstituted at the lower rim by tertiary amide groups and monocharged metal cations in the organic phase

New p-tert-butyl thiacalix[4]arenes functionalized with morpholide and pyrrolidide groups at the lower rim in cone, partial cone, and 1,3-alternate conformations were synthesized, and their receptor properties for monocharged cations (alkali metal and silver ions) were studied using the picrate extraction method and dynamic light scattering (DLS). To evaluate the ability of the p-tert-butyl thiacalix[4]arene derivatives to recognize metal ions, liquid-liquid extraction of their picrate salts has been carried out in a mutually saturated water-dichloromethane system. The degrees of extraction and the extraction constants for monocharged metal cations (Li⁺, Na⁺, K⁺, Cs⁺) have been determined. The ability of the systems, consisting of host and guest molecules, to self-assembly was proved by DLS using a Zetasizer Nano ZS particle size analyzer. It was shown that all the investigated thiacalix[4]arenes are able to form nanoscale particles with silver cations under the experimental conditions. The pyrrolidide derivative in the cone conformation showed both self-association and aggregation processes with lithium cations. The degree of extraction for all the investigated systems that formed nanoscale aggregates in the organic phase was more than 67% and the extraction constants, log K_ex determined by the picrate extraction method, more than 6.     

Substituent effects in the binding of bis(4-fluorobenzyl)ammonium ions by dianilino[24]crown-8

A series of para-substituted dianilino[24]crown-8 (DA24C8) macrocycles were synthesized and their ability to form host-guest complexes with bis(4-fluorobenzyl)ammonium ions (DFA⁺) were investigated. Although these crown ethers contain weakly hydrogen bonding aniline motifs, they do bind DFA⁺ in CDCl₃/CD₃NO₂ solution, presumably in a pseudorotaxane-like manner. A plot of the values of the relative binding strengths (log[K_a(R)/K_a(H)]) versus the Hammett substituent constants σ⁺ of the groups at the para-position of the aniline units suggests that a linear free energy correlation exists for this self-assembly process. The strength of the binding between the crown ether and the thread-like ion can be fine-tuned over a narrow range by judicious choice of the substituting groups.     

Copper(II) and nickel(II) complexes of mono-oxocyclam(5-oxo-1,4,8,11-tetraazacyclotetradecane). Synthetic and potentiometric studies

Summary The macrocyclic mono-oxotetraamine, 5-oxo-1,4,8,11-tetraazacyclotetradecane (mono-oxocyclam=LH) has been prepared by reaction of methyl acrylate with 2,3,2-tetra(1,9-diamino-3,7-diazanonane). The protonation constants of the ligand are log K₁=9.40, log K₂=6.65 and log K₃=2.87 at 25 °C (I=0.1 mol dm^–3 NaClO₄). Detailed potentiometric studies of the interaction of the base with copper(II) and nickel(II) have been carried out. In the pH range 2.5–7.0 two complexes, [CuLH]²⁺ and [CuL]⁺, form; the deprotonated complex being 100% abundant at pH 7. For nickel(II), only [NiL]⁺ forms (log _11–1 = 3.90), the yellow low spin nickel complex reaching its maximum concentration above pH 6. The [CuL][ClO₄] · H₂O and [NiL][ClO₄] 0.5 H₂O complexes have been characterised in the solid state. The nickel(II) complex is square planar with a d-d band at 22625 cm^–1.     

Crystal structure of 4,7,13,16,21,24-hexaoxa-1-aza-10-azoniabicyclo[8.8.8]hexacosane monohydrate picrate

The crystal structure of 4,7,13,16,21,24-hexaoxa-1-aza-10-azoniabicyclo[8.8.8]hexacosane monohydrate picrate, [H(Crypt-222) H₂O]⁺·Pic^? (I), has been studied by X-ray crystallography. The structure of I (space group P2₁/c, a = 9.336 Å, b = 19.497 Å, c = 16.420 Å; β = 94,84°, Z = 4) was solved by direct methods and refined by full-matrix least squares in an anisotropic approximation to R = 0.056 for all 3877 independent reflections collected (CAD-4 automatic diffractometer, λMoK _α). This compound is one of the few representatives of the class of crystal salts containing a 2.2.2-cryptand cation with a protonated nitrogen atom that have been synthesized and studied by X-ray crystallography. The void of the cation contains a water molecule held by three H bonds. Crystal I also has unusual H bonds of C-H…O type that link the neighboring 2.2.2-cryptand cation and the picrate anion.     

Kinetic study of nucleophilic addition to the cycloheptatriene ring in [(C7H8)Fe(Cp)]PF6

Tri-n-butylphosphine, tri-n-butylphosphite, and imidazole add to the cycloheptatriene ring in (C₇H₈)FeCp)⁺ (I) to give cycloheptadienyl adducts (II). The second order rate constants (M^?1 s^?1) in acetone at 25°C are: P(OBu)₃, 0.50; PBu₃, 2250; HIm, 67. The relative nucleophilic reactivities are the same as that found with other coordinated cyclic π-hydrocarbons and with free carbocations. This further supports the recent suggestion [1] that a Ritchie type correlation holds for attack on all complexes of the form (ring)ML_n. The Fe(Cp)⁺ moiety is 11,000 times weaker than Mn(CO)₃⁺ in activating coordinated cycloheptatriene. NaBH₄, MeLi, and NaCH(CO₂Et)₂ also add to the ring in I, indicating that I may have synthetic utility.     

Interaction between Anions and Cationic Metal Complexes Containing Tridentate Ligands with exo‐CH Groups: Complex Stability and Hydrogen Bonding

[Re(CO)₃([9]aneS₃)][BAr′₄] ( 1 ), prepared by reaction of ReBr(CO)₅, 1,4,7‐trithiacyclononane ([9]aneS₃) and NaBAr′₄, forms stable, soluble supramolecular adducts with chloride ( 2 ), bromide, methanosulfonate ( 3 ) and fluoride ( 4 ) anions. These new species were characterized by IR, NMR spectroscopy and, for 2 and 3 , also by X‐ray diffraction. The results of the solid state structure determinations indicate the formation of CH???X hydrogen bonds between the anion (X) and the exo‐C?H groups of the [9]aneS₃ ligand, in accord with the relatively large shifts found by ¹H NMR spectroscopy in dichloromethane solution for those hydrogens. The stability of the chloride adduct contrasts with the lability of the [9]aneS₃ ligand in allyldicarbonyl molybdenum complexes recently studied by us. With fluoride, in dichloromethane solution, a second, minor neutral dimeric species 5 is formed in addition to 4 . In 4 , the deprotonation of a C?H group of the [9]aneS₃ ligand, accompanied by C?S bond cleavage and dimerization, afforded 5 , featuring bridging thiolates. Compounds [Mo(η³‐methallyl)(CO)₂(TpyN)][BAr′₄] ( 6 ) and [Mo(η³‐methallyl)(CO)₂(TpyCH)][BAr′₄] ( 7 ) were synthesized by the reactions of [MoCl(η³‐methallyl)(CO)₂(NCMe)₂], NaBAr′₄ and tris(2‐pyridyl)amine (TpyN) or tris(2‐pyridyl)methane (TpyCH) respectively, and characterized by IR and ¹H and ¹³C NMR spectroscopy in solution, and by X‐ray diffraction in the solid state. Compound 6 undergoes facile substitution of one of the 2‐pyridyl groups by chloride, bromide, and methanosulfonate anions. Stable supramolecular adducts were formed between 7 and chloride, bromide, iodide, nitrate, and perrhenate anions. The solid state structures of these adducts ( 12 – 16 ) were determined by X‐ray diffraction. Binding constants in dichloromethane were calculated from ¹H NMR titration data for all the new supramolecular adducts. The signal of the bridgehead C?H group is the one that undergoes a more pronounced downfield shift when tetrabutylammonium chloride was added to 7 , whereas smaller shifts were found for the 2‐pyridyl C(3)?H groups. In agreement, both types of C?H groups form hydrogen bonds to the anions in the solid state structures.     

Reactions of carbonyl clusters with potentially tridentate thioethers: Crystal and molecular structures of [Os4(CO) 13([12]aneS3)] and [Ru6(CO)15(μ4-η2- CO)([12]aneS3)] [([12]aneS3) = {(CH2) 3S}3]

The reaction of [Os₃(CO)₁₂ with [12]aneS₃ ([12]aneS₃  {(CH₂)₃S}₃) in octane for 6 h, under reflux, led to isolation of two products [Os₃(CO)₁₁([12]aneS₃)] (1) and [Os₄(CO) ₁₃([12]aneS₃)] (2), while with [Ru₃(CO)₁₂] under similar conditions, in THF, a number of products were obtained, including [Ru₄(CO)₁₁([12]aneS₃)] (3), [Ru₅(CO)₁₃([12]aneS₃)] (4), and [Ru₆(CO)₁₆([12]aneS₃)] (5). An X-ray diffraction study of 2 shows that the macrocycle is coordinated to the ‘wingtips’ of an Os₄ butterfly through the two electron pairs on one sulphur atom, while in 5 all three sulphur atoms of the macrocycle coordinate to two of the Ru atoms in a spiked edge-bridged tetrahedral metal framework.