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Addition of 1-alkyl-3-methylimidazolium (C(n)-mim) cations 3-5 to a mixture of bis-phosphonium cation 2 and sodium p-sulfonatocalix[4]arene (1) in the presence of lanthanide ions results in the selective binding of an imidazolium cation into the cavity of the calixarene. The result is a multi-layered solid material with an inherently flexible interplay of the components. Incorporating ethyl-, n-butyl- or n-hexyl-mim cations into the multi-layers results in significant perturbation of the structure, the most striking effect is the tilting of the plane of the bowl-shaped calixarene relative to the plane of the multi-layer, with tilt angles of 7.2, 28.9 and 65.5 degrees , respectively. The lanthanide ions facilitate complexation, but are not incorporated into the structures and, in all cases, the calixarene takes on a 5- charge, with one of the lower-rim phenolic groups deprotonated. ROESY NMR experiments and other (1)H NMR spectroscopy studies establish the formation of 1:1 supermolecules of C(n)-mim and calixarene, regardless of the ratio of the two components, and indicate that the supermolecules undergo rapid exchange on the NMR spectroscopy timescale.

The hybrid salt bis(2-methylimidazo[1,5-a]pyridin-2-ium) hexachloridostannate( IV), (C8H9N2)2[SnCl6], crystallizes in the monoclinic space group P21/n with the asymmetric unit containing an Sn0.5Cl3 fragment (Sn site symmetry 1) and one organic cation. The five- and six-membered rings in the cation are nearly coplanar; bond lengths in the pyridinium ring of the fused core are as expected; the C--N/C bond distances in the imidazolium entity fall in the range 1.337 (5)-1.401 (5) Å. The octahedral SnCl62- dianion is almost undistorted with the Sn--Cl distances varying from 2.4255 (9) to 2.4881 (8) Å and the cis Cl--Sn--Cl angles approaching 90°. In the crystal, π-stacked chains of cations and loosely packed SnCl62- dianions form separate sheets alternating parallel to (101). Most of the numerous C--H• • •Cl--Sn contacts between the organic and inorganic counterparts with the H• • •Cl distances above the van der Waals contact limit of 2.85 Å are considered a result of crystal packing. [ABSTRACT FROM AUTHOR]

Quaternary phosphonium salts are popular candidates used in many chemical transformations and synthetic chemistry, notably in catalysis. We have examined the single crystals of two bulky phosphonium compounds, tetra([1,1′-biphenyl]-4-yl) phosphonium dicyanamide (C48H36P+·N(CN)2−, compound 1), and tetra([1,1′-biphenyl]-4-yl) phosphonium bromide hydrate (C48H36P+·Br−, CH3CN, H2O, compound 2), and herein report the structural properties for the compounds with an emphasis on the influence of the ion-ion interaction towards self-assembly; the overall self-assembly for both structures is very similar, with subtle differences in the cell parameters. The symmetrical tetra ([1,1′-biphenyl]-4-yl) phosphonium cations in both compounds self-assembled to form robust stacked columns in the solid-state, with voids occupied by anions or solvent molecules. Quantitative examination of intermolecular interactions using Hirshfeld surface analysis found that classical and non-classical hydrogen bonding appears to be the dominant contributor in stabilizing the self-assembly in both cases. The present work can not only benefit in understanding the mutual interaction between the sterically encumbered tetra ([1,1′-biphenyl]-4-yl) phosphonium cations and between counterions, but also provide insights for the self-assembled arrays in the solid-state. [ABSTRACT FROM AUTHOR]

The title compound, [Fe(C3H7NO)6][Cd2Cl7], crystallizes in the trigonal space group R3̅ and is assembled from discrete [Fe(DMF)6] 3+ cations (DMF = N,Ndimethylformamide) and [Cd2Cl7] 3- anions. In the cation, the iron(III) atom, located on a special position of 3̅ site symmetry, is coordinated by six oxygen atoms from DMF ligands with all Fe—O distances being equal [2.0072 (16) A˚ ]. A slight distortion of the octahedral environment of the metal comes from the cis O—Fe—O angles deviating from the ideal value of 90 [86.85 (7) and 93.16 (7)] whilst all the trans angles are strictly 180. The central Cl atom of the [Cd2Cl7] 3- anion is also located on a special position of 3̅ site symmetry and bridges two corner sharing, tetrahedrally coordinated CdII atoms. The two Cd atoms and the central Cl atom are colinear. The two sets of terminal chloride ligands on either side of the dumbbell-like anion are rotated relative to each other by 30. In the crystal, the cations and anions, stacked one above the other along the c-axis direction, are held in place principally by electrostatic interactions. There are also C—H...Cl and C—H...O interactions, but these are rather weak. Of the six crystal structures reported to date for ionic salts of [Fe(DMF)6] n+ cations (n = 2, 3), five contain FeII ions. The title compound is the second example of a stable compound containing the [Fe(DMF)6] 3+ cation. The existence of both [Fe(DMF)6] 2+ and [Fe(DMF)6] 3+ cations shows that the DMF ligand coordination sphere can accommodate changes in the charge and spin states of the metal centre. [ABSTRACT FROM AUTHOR]

Four multi-component complexes based on p-sulfonatocalix[4]arene anion, the methyltriphenylphosphonium cation, lanthanide ions (Gd(III)) and different ionic liquid-based cations (1-methyl-3-butylimidazolium, 1-methyl-3-octylimidazolium and 1,4-bis((3-methylimidazolidinyl)methyl)benzene) were synthesised and structurally characterised. Common bilayer arrangements are formed in the extended structures of all four complexes, though the bilayer thicknesses varies depending on the components involved. Molecular capsule formation is facilitated by the inclusion of methyltriphenylphosphonium, 1-methyl-3-butylimidazolium and 1,4-bis((3-methylimidazolidinyl)methyl)benzene cations, but not in the case of the 1-methyl-3-octylimidazolium cation. Molecular capsule size depends on the nature of the included guest cation, and methyltriphenylphosphonium cations fill compact spaces between calixarenes in these new bilayer arrays. [ABSTRACT FROM AUTHOR]

The organisation of the p-xylylenebis(triphenylphosphonium) dication in the solid state, in crystals formed under a variety of conditions, at different pH values and in the presence of THF and other potential building moieties including p-sulfonatocalix[4]arene, 1-methyl-3-butylimidazolium and aquated gadolinium(III) has been investigated using single crystal X-ray diffraction studies. Striking changes in the dication conformations (cis- and trans-) that contribute to the different crystal packings of the dication (two-dimensional layerings and three-dimensional scaffoldings) have been established for five different compounds. The interplay and the self-assembled arrays of the dication with other incorporated components and the overall non-covalent interactions have been quantified using Hirshfeld surface analyses. [ABSTRACT FROM AUTHOR]

Eight organic salts made up of two different organic phosphonium monocations, tetraphenylphosphonium or benzyltriphenylphosphonium, and common anions of different shape, size and charge distribution have been structurally authenticated. The crystal packing for the tetraphenylphosphonium cations involves one-dimensional infinite stacked columns incorporating translational quadruple embraces (TQPE) regardless of the type of counter ion. As for benzyltriphenylphosphonium salts, different packing arrays were obtained with different anions. Interestingly, the anions control the intermolecular packing of the same phosphonium cation, while hydrogen bonding is found to be the dominant contributor in the overall self-assembly. Hydrophobic interactions between the phosphonium cations driven by the phenyl–phenyl embrace involving π⋯π and/or C–H⋯π interactions also contribute to the cohesion of the structures. Charge-assisted hydrogen bonding and halogen bonding were also evident, which are relatively strong compared to classical hydrogen bonds, as judged from the short intermolecular distances. The interactions have also been quantified using Hirshfeld surfaces analyses. [ABSTRACT FROM AUTHOR]

The interplay of organic dications bearing various n-alkylimidazolium termini substituted at different positions on a bis(methylene)phenyl ring and p-sulfonatocalix[4]arene, along with tetraphenylphosphonium cations and hydrated lanthanides (Ce3+, Er3+ and Gd3+), afforded various self-assembled solid-state structures. The host–guest binding behaviour of the dications and p-sulfonatocalix[4]arene was carefully investigated by crystallographic studies including their interactions in the solution state, but in the absence of phosphonium and lanthanide cations via1H NMR experiments. [ABSTRACT FROM AUTHOR]

Solution mediated organization of p-sulfonatocalix[4]arene, benzyltriphenylphosphonium cations, and bis(triethylammoniomethyl)-benzene dications in the solid state results in the ammonium dications preferentially binding in the cavities of two opposing calixarenes which take on a −3 charge, with the phosphonium cations arranged in a separate 2D sheet relative to the calixarene bilayer. [ABSTRACT FROM AUTHOR]

Structure determinations for some Co(III) complexes of simple derivatives of the cage hexamine 3,6,10,13,16,19-hexa-azabicyclo[6.6.6]icosane ("sarcophagine") show that there is no evidence that the H-bonding involving the NH centres of the complex cations is influenced by electronic effects due to the substituents. "H-bond chelation" of chloride anions or water molecules results in retention of the symmetrical lel3 conformation. [ABSTRACT FROM AUTHOR]

Multi-component self-assembly involving bis-phosphonium and bis-imidazolium cations, and p-sulfonatocalix[4]arene feature supermolecules based on two geometrically opposed calixarenes end-capping each bis-imidazolium cation, either with coordinated lanthanide cations or with the phosphonium cations residing around the upper rim of the calixarenes. The nature of the calixarene-bis-imidazolium interaction is mapped out using Hirshfeld surface analysis. 1H NMR and ROESY experiments establish the formation of the supermolecules of the bis-imidazolium cation and calixarenes in solution. [ABSTRACT FROM AUTHOR]