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Two one-dimensional coordination polymers, PhHg(3-alkoxycyclobutene-1,2-dione-4-thiolate) (alkoxy = OMe and OEt), have been synthesised, characterised spectroscopically, crystallographically and through computational chemistry techniques. Both species exhibit intermolecular Hg⋯O σ-hole spodium bonding as well as intramolecular Hg⋯O π-hole spodium bonding. In the ethoxy species there are complementary σ-hole O⋯S chalcogen bonds to the Hg⋯O σ-hole spodium bonding as well as orthogonal Hg⋯S π-hole spodium bonding. Each of the coordination polymers is connected into a supramolecular layer. For the methoxy derivative, the layer features π(cyclobutene)⋯π(phenyl) stacking and side-on C＝O⋯π(cyclobutene)/anti-parallel carbonyl⋯carbonyl interactions. For the ethoxy species, Hg⋯S, offset π(cyclobutene)⋯π(cyclobutene) stacking and C＝O⋯π(cyclobutene) interactions occur within the layer. In each case, weak C–H⋯π interactions operate between the two-dimensional arrays. The nature of the electron transfer responsible for the spodium/chalcogen bonding has been established. In terms of QTAIM energies, those associated with Hg⋯O σ-hole spodium bonds were in the range of 17.5 to 23.3 kJ mol−1, which were less than the energies computed for the intramolecular Hg⋯O π-hole spodium bonds in each case (31.0 to 43.6 kJ mol−1). The lowest energies for the intermolecular Hg⋯O spodium bonding were computed for the ethoxy species, which correlates with the compensating Hg⋯S π-hole spodium bonding (2 × 11.0 kJ mol−1) and O⋯S chalcogen bonding (12.5 kJ mol−1). The electron transfer leading to the Hg⋯O/S spodium bonding involves donation of an oxygen- or sulphur-bound lone pair of electrons to the σ*(Hg–C) orbital, with the intramolecular Hg⋯O spodium bond involving two lone pair interactions. The O⋯S chalcogen bond is assigned to LP(O) → σ*(C–S). [ABSTRACT FROM AUTHOR]

This study delves into the intriguing realm of chalcogen-bonding interactions, specifically focusing on tellurium(II) and/or tellurium(IV) interactions with iodide species within six crystals. Utilising comprehensive computational chemistry calculations and underpinned by crystallographic data retrieved from the Cambridge Structural Database, this research elucidates the supramolecular aggregation, bonding nature and interaction energetics of Te...I non-covalent bonds in a series of crystals containing each of tellurium(II), tellurium(IV) and iodide. The investigation encompasses a variety of molecular assemblies, ranging from zero-dimensional to complex three-dimensional architectures. Tellurium(II) atoms formed Te...I interactions in six of the crystals but tellurium(IV) participated in Te...I interactions in only three crystals despite there being equal numbers of tellurium(II) and tellurium(IV) atoms in the zero- and onedimensional assemblies. Several computational tools, including Molecular Electrostatic Potential (MEP) surfaces, Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) analyses, provide a nuanced understanding of the electron density topology and charge transfer mechanisms. In some assemblies, where the Te...I interactions are ~3.2 Å, the interaction energies are very large, i.e. 25.6 to 38.8 kcal mol-1, suggesting partial covalent character, an observation corroborated by the NBO analysis; longer Te...I separations correlate with reduced energies, i.e. 3.1 to 7.0 kcal mol-1. Crucially, it is noteworthy that the Te...I interactions identified in this study are distinctly characterised as chalcogen bonds, rather than halogen bonds. [ABSTRACT FROM AUTHOR]

A series of five S-benzyl esters of pyrrolidine dithiocarbamate, differing only in the substituent in the 4-position of the benzyl group, i.e. (CH2CH2)2NC(＝S)SCH2C6H4-4-Y for Y = Cl, Br, I, Me and NO2 (1–5), have been investigated by crystallographic and computational chemistry techniques, including analyses of the calculated Hirshfeld surfaces and the calculation of interaction energies. Remarkable differences in molecular conformations, e.g. almost 90° differences in the C–S(thioether)–C(methylene)–C torsion angles, are related to packing effects as revealed through unrestricted geometry-optimisation calculations. The influence of the remote substituent, Y, upon the molecular packing is crucial with four different packing patterns elucidated. In the chlorine derivative, 1, Cl⋯Cl contacts feature between layers having C–H⋯π interactions. In each of the isomorphous bromine (2) and iodine (3) derivatives, X⋯S halogen-bonding is detected within linear supramolecular chains which assemble into layers through phenyl-C–H⋯S(thione), methylene-C–H⋯π(phenyl) and off-set phenyl-π⋯π(phenyl) stacking. Layers are also evident in the methyl species, 4, with directional pyrrolidine-C–H⋯π(phenyl) and π(phenyl)⋯π(phenyl) interactions apparent between molecules. In the three-dimensional architecture of nitro derivative 5, methylene-C–H⋯π(phenyl) and long phenyl-C–H⋯O(nitro) interactions are discerned. The X⋯S halogen-bonding is more significant for 3cf.2 based on geometric criteria and calculated interaction energies. [ABSTRACT FROM AUTHOR]

Two polymorphs, α (Z′ = 4) and β (Z′ = 1), of an N2,6-diaryl-1,3,5-triazine-2,4-diamine derivative have been isolated at different times from ethanol solution. Significant conformational variability in the five independent molecules is apparent. The molecular packing is distinct but features some commonalties such as the formation of eight-membered {⋯HNCN}2 synthons mediated by phenylamino-N–H⋯N(triazine) hydrogen bonds and (external) supporting amino-N–H⋯C(phenylamino) contacts. The dimeric aggregates are connected into two-dimensional arrays via triazine-amino-N–H⋯O(methoxy) hydrogen bonds. In each crystal, the interactions involve chemically equivalent triazine-N, methoxy-O and amino-H atoms. However, the connections between layers is distinct, notably with superimposition of pairs of molecules via π⋯π stacking between all three aromatic rings in the α-form being restricted to π⋯π stacking between triazine rings only in the β-form. The experimental molecular structures have been subjected to a conformational analysis and compared to the geometry-optimised molecule. The MEP and NPA have been evaluated, and the molecular packing investigated by the analysis of the calculated Hirshfeld surfaces, interaction energies, NCI plots and energy frameworks. The kinetic α-polymorph crystallises with Z′ = 4 and features expansive, stabilising π⋯π interactions in the molecular packing which is achieved by relatively unstable conformations of three of the four molecules. The α-polymorph is readily converted to the thermodynamic β-polymorph, which has the most stable molecular conformation, in solution, with the egress of time, and in the solid-state via heating of single crystals and powdered samples. The adoption of the crystal form results from an interplay between global molecular packing and stability of molecular conformation. [ABSTRACT FROM AUTHOR]

Crystallography shows the universal adoption of supramolecular chains featuring hydroxyl-O–H⋯O(hydroxyl) hydrogen bonding in crystals of (HOCH2CH2)2NC(＝S)N(H)(C6H4Y-4) for Y = H (1), Me (2), Cl (3) and NO2 (4). However, distinct topologies, i.e. linear (Y = H), helical (Y = Me and Cl) and zig-zag (Y = NO2) are noted with major differences in the pitch of the polymer. Geometry-optimisation, MEP and NPA analyses show a distinct electronic structure for the Y = NO2 derivative, in particular relating to the activation of the aryl ring. An exhaustive analysis of the molecular packing (point-to-point interactions, crystal structure similarity, Hirshfeld surface analysis, NCI and QTAIM, interaction energies and energy frameworks) points to the importance of C–H⋯π(aryl) interactions in stabilising the chains but these have a considerably reduced influence in the crystal with Y = NO2 (4), where π(aryl)⋯π(aryl) interactions are important. The more open arrangement for the linear chain in 1 facilitates the formation of C–H⋯π(aryl) interactions and the more compact arrangements enable the formation of stabilising, intra-chain methylene-C–H⋯S(thione) interactions 2–4. This study highlights the role of second-tier non-covalent interactions in the arrangement of conventional hydrogen bonding interactions. [ABSTRACT FROM AUTHOR]

The crystallographic structures of 12 palladium xanthates, Pd(S2COR)2 (R = alkyl) show a uniform adoption of square-planar PdS4 geometries. Supramolecular aggregation in 1 (R = Me), 2 (Et) and 3 (n-Pr) is based on secondary Pd…S interactions, which are “turned off” when the bulk of R increases. In 4 (i-Pr), C–H…S hydrogen bonding is present. In each of 2–4, C–H…π(PdS2C) interactions are incorporated within the architecture, stabilised by Pd…S secondary- or C–H…S hydrogen-bonding. In 5–12 (R = n-Bu, i-Bu, n-Pent, i-Pent, neoPent, n-Hex, i-Hex, neoHex), varying numbers of stand-alone C–H…π(PdS2C) interactions involving different hydrogen donors uniformly stabilise supramolecular chains in their crystal structures. In order to determine the relative importance of the various intermolecular interactions and packing effects, a computational study using dispersion-corrected density-functional theory was performed on 3 (R = n-Pr). The results showed that the most significant contributors to the stability of the crystal structure are Pd…S interactions followed closely by C–H…π(PdS2C) interactions. Two non-specific hydrophobic interactions also contribute to the overall packing to a lesser extent. The utility of Pd(S2COR)2 to function as synthetic precursors for PdS nanoparticles and thin films was also investigated. Aerosol-assisted-CVD on representative examples generated PdS films with either matted, needle-like or granular morphologies depending on temperature and substrate. Solvothermal (ethylene glycol) decomposition generated sulphur-rich PdS nanoparticles with diameters 120 nm (7 and 10)–400 nm (8). When dodecanethiol was employed as a capping agent, PdS1.75 nanoparticles ＜10 nm were generated from 1. [ABSTRACT FROM AUTHOR]

Dimethyl sulphoxide (DMSO) molecules in their all-organic solvates were shown to interact with arene rings of organic molecules via DMSO-O(lone pair)⋯π(arene) or DMSO-S(lone pair) ⋯π(arene) interactions in approximately 5-6% of their crystal structures, often in conjunction with conventional hydrogen bonding involving the O(DMSO) atom, resulting in zero-, one- and two-dimensional supramolecular architectures. Zero-, one- and two-dimensional supramolecular architectures were also found to be sustained by parallel S==O⋯π(arene) interactions operating in combination with hydrogen bonding. [ABSTRACT FROM AUTHOR]

A series of five S-benzyl esters of pyrrolidine dithiocarbamate, differing only in the substituent in the 4-position of the benzyl group, i.e. (CH2CH2)2NC(＝S)SCH2C6H4-4-Y for Y = Cl, Br, I, Me and NO2 (1–5), have been investigated by crystallographic and computational chemistry techniques, including analyses of the calculated Hirshfeld surfaces and the calculation of interaction energies. Remarkable differences in molecular conformations, e.g. almost 90° differences in the C–S(thioether)–C(methylene)–C torsion angles, are related to packing effects as revealed through unrestricted geometry-optimisation calculations. The influence of the remote substituent, Y, upon the molecular packing is crucial with four different packing patterns elucidated. In the chlorine derivative, 1, Cl⋯Cl contacts feature between layers having C–H⋯π interactions. In each of the isomorphous bromine (2) and iodine (3) derivatives, X⋯S halogen-bonding is detected within linear supramolecular chains which assemble into layers through phenyl-C–H⋯S(thione), methylene-C–H⋯π(phenyl) and off-set phenyl-π⋯π(phenyl) stacking. Layers are also evident in the methyl species, 4, with directional pyrrolidine-C–H⋯π(phenyl) and π(phenyl)⋯π(phenyl) interactions apparent between molecules. In the three-dimensional architecture of nitro derivative 5, methylene-C–H⋯π(phenyl) and long phenyl-C–H⋯O(nitro) interactions are discerned. The X⋯S halogen-bonding is more significant for 3cf.2 based on geometric criteria and calculated interaction energies. [ABSTRACT FROM AUTHOR]