Secondary Bonding Interactions Research Articles

Te⋯I secondary-bonding interactions in crystals containing tellurium(ii), tellurium(iv) and iodide atoms: supramolecular aggregation patterns, nature of the non-covalent interactions and energy considerations

The importance of σ-hole bonding is emphasised in a series of mixed tellurium(ii)/tellurium(iv)/iodide crystals.

Additive-Assisted Perylene Polymorphism Controlled via Secondary Bonding Interactions

The influence of molecular additives or impurities on crystal growth, morphology, and polymorphism has broad importance in various fields of material science and pharmaceutical engineering. There are numerous examples demonstrating the effect of impurities on the crystallization of pharmaceutical substances; however, systematic studies on the additives’ effect on crystallization and properties of organic semiconductors have not yet been reported. Here, we studied additive-assisted crystallization of a model aromatic hydrocarbon compound–perylene–to elaborate the crystal engineering tool for organic optoelectronics and to reveal the underlying mechanism. Anthracene, tetracene, 9,10-diphenylanthracene, and rubrene were used as representative additives. We found the optimal additive and conditions for perylene crystallization allowing us to control its polymorphic outcome. The addition of 9,10-diphenylanthracene was demonstrated to lead to a preferable crystallization of metastable β-form of perylene, whereas in the neat conditions, α-form was typically obtained as a stable one. The crystallization of perylene with 9,10-diphenylanthracene in high concentrations resulted in their stoichiometric co-crystallization. The perylene:9,10-diphenylanthracene co-crystal structure and optoelectronic properties were evaluated. The co-crystal demonstrated a photoluminescence quantum yield of 45% and hole mobility of 0.025 cm2/V s. The co-crystal structure analysis pointed on the stabilization of herringbone packing of perylene by interlayer C–H···π interactions, allowing the 9,10-diphenylanthracene layers to serve as the template for perylene β-polymorph nucleation. The results obtained could serve as the basis for crystallization control and engineering of high-performance materials in organic optoelectronics.

Supramolecular Association via Hg···S Secondary-Bonding Interactions in Crystals of Organomercury(II) Species: A Survey of the Cambridge Structure Database

The Cambridge Structural Database has been surveyed for crystals featuring organo-Hg···S secondary-bonding interactions within supramolecular aggregates. Nearly 50% of crystals where Hg···S interactions could potentially form, featured Hg···S contacts within zero- or one-dimensional supramolecular assemblies with only a few examples of two-dimensional arrays featuring Hg···S interactions. This high propensity of Hg···S contact formation reflects the inherent thiophilic nature of mercury but also the relatively open access to mercury owing to the linear C–Hg–S coordination geometries, the prevalence of close intramolecular Hg···S, Hg···O and Hg···N interactions notwithstanding.

Supramolecular aggregation featuring Hg⋯S secondary-bonding interactions in crystals of mercury(ii) species augmented by computational chemistry calculations

A CSD survey reveals the presence of Hg⋯S interactions within zero-, one- and two-dimensional aggregation patterns in non-organomercury crystals. Theory confirms the stabilising nature of σ-/π-holes or positive belts formed at the mercury atom.

Supramolecular architectures featuring Se⋯N secondary-bonding interactions in crystals of selenium-rich molecules: a comparison with their congeners

The importance of Se⋯N chalcogen-bonding in supramolecular assembly is demonstrated.

Supramolecular aggregation patterns featuring Se⋯N secondary-bonding interactions in mono-nuclear selenium compounds: A comparison with their congeners

• Selenium⋯nitrogen secondary-bonding is important in relevant crystal structures. • Isolated Se⋯N interactions are found in 9% of crystals containing Se and N. • Se⋯N(selenadiazole) interactions occur in 75% of crystals where they can form. • Zero-, one-, two- and three-dimensional architectures feature Se⋯N interactions. • One-dimensional chains are found in 45% of examples. An evaluation of the Cambridge Structural Database for crystals containing Se⋯N secondary--bonding interactions was conducted. The presence of Se⋯N secondary-bonding interactions has been established in nearly 9% of crystals of mono-nuclear selenium compounds where such interactions can potentially form, that is, having at least one nitrogen atom. The Se⋯N interactions feature in 71 zero-dimensional, usually di-nuclear aggregates, 63 one-dimensional chains and tapes, and smaller numbers of two- and three-dimensional arrays, that is seven and one, respectively. Selenium(II) compounds form the majority of the dataset with only eight selenium(IV) compounds included in the survey. In most cases (112 out of 142), the selenium centre forms a single Se⋯N contact with 26 aggregates having a selenium atom forming two contacts and four examples where three Se⋯N contacts are evident. The great propensity of selenadiazole rings (75%) and selenocyanates (50%) to form Se⋯N secondary-bonding interactions in their crystals is particularly noteworthy.

Synthesis and Single Crystal X-ray Studies of Cyclic Te(IV) Diiodide

The cyclic tellurium(IV) diiodide, 2-Methyl-1,1-diiodo-1-telluracyclopentane, was prepared in good yields at room temperature by the incorporation of tellurium powder across Carbon–Iodine bond in presence of sodium iodide and acetone. The cyclic tellurium(IV) diiodide compound has been established by proton and 13carbon NMR spectroscopy along with elemental analysis. This compound was further characterized by 125Te NMR in DMSO. Molecular structures of cyclic tellurium(IV) diiodide was also established by single-crystal X-ray studies. In solid-state, molecular structures of cyclic tellurium(IV) diiodidepossess scarcely observed Te…I secondary bonding interactions (SBIs) and two molecule are co-crystallized. Both molecules are interconnected with each other by Te…I secondary bonding interactions. The five-membered rings acquire a twist-boat shape structure. Observed C–Te–C bond angles for molecule A, and molecule B are 85.0(1)°& 85.4(2)° respectively. Similarly observed, I–Te–I bond angles for both molecule A & B are 174.5(1)°&174.2(1)° respectively.

New Crystal Structures of Rare‐Earth Metal(III) Oxotellurates(IV) RE2Te3O9: A1‐Type (RE=La, Ce) and A2‐Type (RE=Pr, Nd)

AbstractThe new rare‐earth metal(III) oxotellurates(IV) RE2Te3O9 (RE=La−Nd) of the so far unknown A‐type structure can be obtained as needle‐shaped single crystals through solid‐state reactions of the corresponding binary oxides. Their crystal structures were determined as A1‐type for RE=La and Ce or A2‐type for RE=Pr and Nd by single‐crystal X‐ray diffraction. Both structure types crystallize in the monoclinic crystal system, but in two different non‐centrosymmetric space groups: the A1‐type with Z=8 in space group P21 (La2Te3O9: a=569.54(3), b=2230.12(13), c=1464.71(4) pm, β=101.205(3)°; Ce2Te3O9: a=567.02(3), b=2222.61(13), c=1457.13(9) pm, β=101.134(3)°) or the A2‐type with Z=16 in space group Cc (Pr2Te3O9: a=2838.61(16), b=563.89(3), c=2522.08(15) pm, β=118.816(3)°; Nd2Te3O9: a=2826.38(16), b=561.47(3), c=2511.94(15) pm, β=118.841(3)°). In spite of the differences in the unit‐cell parameters and the symmetry, both structures consist of quite similar fundamental building blocks (FBBs) consisting of eight crystallographically distinct rare‐earth metal‐oxygen polyhedra with C.N.(RE3+) from seven to nine and always twelve different ψ1‐tetrahedral oxotellurate(IV) anions [TeO3]2−, which show a high number of secondary bonding interactions (SBIs) with each other in all four cases.

Chalcogen-Bonding Interactions in Telluroether Heterocycles [Te(CH2 )m ]n (n=1-4; m=3-7).

The Te⋅⋅⋅Te secondary bonding interactions (SBIs) in solid cyclic telluroethers were explored by preparing and structurally characterizing a series of [Te(CH2)m]n (n=1–4; m=3–7) species. The SBIs in 1,7‐Te2(CH2)10, 1,8‐Te2(CH2)12, 1,5,9‐Te3(CH2)9, 1,8,15‐Te3(CH2)18, 1,7,13,19‐Te4(CH2)20, 1,8,15,22‐Te4(CH2)24 and 1,9,17,25‐Te4(CH2)28 lead to tubular packing of the molecules, as has been observed previously for related thio‐ and selenoether rings. The nature of the intermolecular interactions was explored by solid‐state PBE0‐D3/pob‐TZVP calculations involving periodic boundary conditions. The molecular packing in 1,7,13,19‐Te4(CH2)20, 1,8,15,22‐Te4(CH2)24 and 1,9,17,25‐Te4(CH2)28 forms infinite shafts. The electron densities at bond critical points indicate a narrow range of Te⋅⋅⋅Te bond orders of 0.12–0.14. The formation of the shafts can be rationalized by frontier orbital overlap and charge transfer.

Precise Steric Control over 2D versus 3D Self-Assembly of Antimony(III) Alkoxide Cages through Strong Secondary Bonding Interactions.

Antimony(III) alkoxide cages were designed as building blocks for predictable supramolecular self-assembly. Supramolecular synthons featuring two Sb···O secondary bonding interactions (SBIs), each SBI stronger than 30 kJ/mol, were used to drive the formation of the supramolecular architectures. Judicious choice of pendant groups provided predictable control over the formation of self-assembled 3D columnar helices, which crystallized with hollow morphologies, or a self-assembled 2D bilayer. The Sb-O stretching frequency provides a spectroscopic signature of Sb···O SBI formation.

Chalcogen–chalcogen secondary bonding interactions in trichalcogenaferrocenophanes

The solid-state structures of all members in the series of trichalcogenaferrocenophanes [Fe(C5H4E)2E′] (E, E′ = S, Se, Te) (1–9) have been explored to understand the trends in secondary bonding interactions (SBIs) between chalcogen elements sulfur, selenium, and tellurium. To complete the series, the crystal structures of the four hitherto unknown complexes [Fe(C5H4S)2Te] (3), [Fe(C5H4Se)2S] (4), [Fe(C5H4Se)2Te] (6), and [Fe(C5H4Te)2S] (7) have been determined in this contribution. The packings of all complexes 1–9 were considered by DFT calculations at the PBE0/pob-TZVP level of theory using periodic boundary conditions. The intermolecular close contacts were considered by QTAIM and NBO analyses. The isomorphous complexes [Fe(C5H4S)2S] (1), [Fe(C5H4S)2Se] (2), and [Fe(C5H4Se)2Se] (5a) form dimers via weak interactions between the central chalcogen atoms of the two trichalcogena chains of adjacent complexes. In the second isomorphous series consisting of [Fe(C5H4Se)2S] (4) and 5b, the complexes are linked together into continuous chains by short contacts via the terminal selenium atoms. The intermolecular chalcogen–chalcogen interactions are significantly stronger in complexes [Fe(C5H4S)2Te] (3), [Fe(C5H4Se)2Te] (6), and [Fe(C5H4Te)2E′] (E′ = S, Se, Te) (7–9), which contain tellurium. The NBO comparison of donor–acceptor interactions in the lattices of [Fe(C5H4S)2S] (1), [Fe(C5H4Se)2Se] (5a and 5b), and [Fe(C5H4Te)2Te] (9) indeed shows that the n(5pTe)2 → σ*(Te–Te) interactions in 9 are the strongest. All other interaction energies are significantly smaller even in the case of tellurium. The computed natural charges of the chalcogen atoms indicate that electrostatic effects strengthen the attractive interactions in the case of all chalcogen atoms.

Chalcogen–Nitrogen Secondary Bonding Interactions in the Gas Phase – Spectrometric Detection of Ionized Benzo‐2,1,3‐telluradiazole Dimers

AbstractThe mass spectra of benzo‐2,1,3‐chalcogenadiazoles, acquired from the equilibrium conditions of the UV‐laser desorption/ionization plume, contain isotopic patterns that are characteristic of protonated and ionized dimers. Dispersion‐corrected DFT modeling shows that the most stable structures of these dimers feature the supramolecular four‐membered Te2N2 ring, which is pervasive in the crystal structures of these compounds. These observations provide the first evidence of the persistence of Te–N supramolecular association in the gas phase.

Tellurium derivatives of 3-acetyl-2,5-dimethylthiophene: Synthetic and structural aspects

Oxidative addition of α-bromo-3-acetyl-2,5-dimethylthiophene to elemental tellurium and aryltellurium(II) bromide provides direct routes to (2,5-dimethyl-3-thiophenoylmethyl)tellurium(IV) dibromides, (Me2TpnCOCH2)2TeBr2 (1a; Me2Tpn = 2,5-Me2-3-C4HS) and Ar(Me2TpnCOCH2)TeBr2 (Ar = 1-C10H7, Npl, 2a; 2,4,6-Me3C6H2, Mes, 3a). The chloro analogs of 2a and 3a, Ar(Me2TpnCOCH2)TeCl2 (Ar = Npl, 2b; Mes, 3b) and derivative when Ar = Anisyl (anisyl = 4-MeOC6H4, 4b) were prepared by the condensation reaction of methyl ketone, Me2TpnCOCH3 with NplTeCl3, MesTeCl3 and anisylTeCl3 respectively while the chloro analog of 1a, bis(2,5-dimethyl-3-thiophenoylmethyl)tellurium(IV) dichloride, (Me2TpnCOCH2)2TeCl2 (1b) was obtained by the condensation reaction of methyl ketone, Me2TpnCOCH3 with TeCl4. Metathesis of these products (1a–b, 2a–b, 3a–b and 4b) with an alkali iodide affords the iodo analogs 1c, 2c, 3c and 4c. These diorganotellurium dihalides are reduced with aqueous bisulfite to diorganotellurides 1–4, which can be oxidized readily with dihalogens to the desired diorganotellurium(IV) dihalides. The crystal structures of the Te(IV) compounds 1b, 2a, 3c and 4b have been studied and all the Te(IV) compounds, the carbonyl functionalized organic moiety, show intramolecular 1,4–Te⋯O secondary bonding interaction (SBI). In the crystal lattice of 2a, the intermolecular Te⋯Br secondary bonding interactions are evident and result in a dimer. They get further associated via C–H⋯Br secondary interactions to form a 3D supramolecular motifs. In 1b, 3c and 4b supramolecular motifs are formed through C–H⋯O and C–H⋯Cl interactions.

Secondary Bonding Interactions in Biomimetic [2Fe−2S] Clusters

A series of synthetic [2Fe-2S] complexes with terminal thiophenolate ligands and tethered ether or thioether moieties has been prepared and investigated in order to provide models for the potential interaction of additional donor atoms with the Fe atoms in biological [2Fe-2S] clusters. X-ray crystal structures have been determined for six new complexes that feature appended Et (1(C)), OMe (1(O)), or SMe (1(S)) groups, or with a methylene group (2(C) ), an ether-O (2(O)), or an thioether-S (2(S)) linking two aryl groups. The latter two systems provide a constrained chelate arrangement that induces secondary bonding interactions with the ether-O and thioether-S, which is confirmed by density functional theory (DFT) calculations that also reveal significant spin density on those fifth donor atoms. Structural consequences of the secondary bonding interactions are analyzed in detail, and effects on the spectroscopic and electronic properties are probed by UV-vis, Mössbauer, and (1)H NMR spectroscopy, as well by SQUID measurements and cyclic voltammetry. The potential relevance of the findings for biological [2Fe-2S] sites is considered.

Acylmethyl(aryl)tellurium(iv,ii) derivatives: intramolecular secondary bonding and steric rigidity

Electrophilic substitution of acylmethanes (methyl ketones), RCOCH3 (R = i-Pr, 1; Et, 2; Me, 3) with aryltellurium trichlorides, ArTeCl3 (Ar = 1-C10H7, Np, A; 2,4,6-Me3C6H2, Mes, B; 4-MeOC6H4, Anisyl, C) under mild conditions affords the corresponding acylmethyl(aryl)tellurium dichlorides (RCOCH2)ArTeCl2. Reduction of the dichlorides, gives tellurides, (i-PrCOCH2)ArTe, 1A-1C, which give the corresponding dihalides, (i-PrCOCH2)ArTeX2 (X = Cl, 1Aa-1Ca; Br, 1Ab-1Cb; I, 1Ac-1Cc) when reacted in situ with SO2Cl2, Br2 or I2. The unsymmetric tellurides are labile towards disproportionation and attempts to obtain them lead to the isolation of Ar2Te2 except in the case of (i-PrCOCH2)MesTe (1B), which represents an interesting example of a kinetically stable aryl(alkyl)telluride. All the dihalomesityltellurium(IV) derivatives show separate 1H and 13C NMR signals for the ortho methyls irrespective of the sizes of R and X ligands. The telluride, 1B with free rotation about Te-C(mesityl) bond shows, like the unsymmetric diorganotellurium(IV) dihalides, only one 125Te NMR signal. The 1,4-chelating behavior of the acyl ligand among diorganotellurium(IV) compounds is inferred from the X-ray diffraction data for 1Aa, 1Ac, 1Ba, 1Bb, 1cA and 1Cc which are indicative of the presence of intramolecular Te...O secondary bonding interactions (SBIs) at least in the solid state. As a consequence, steric repulsion in case of the mesityltellurium(IV) derivatives, 1Ba and 1Bb, reaches the threshold so as to cause loss of two-fold rotational symmetry of the mesityl group about the Te-C(mesityl) bond axis. Intermolecular C-HO...O H-bonding interactions appears to stabilize such an orientation of the aryl ligand at least in the solid state.

Room-Temperature Insertion of Elemental Tellurium into the Csp3−Br and −I Bonds of α-Bromo- and α-Iodopinacolone

Pinacolyltellurium(IV) dihalides, (t-BuCOCH2)2TeX2 (X = Br (1b), I (1c)) and Ar(t-BuCOCH2)TeCl2 (Ar = 1-C10H7 (Np) (2a), 2,4,6-Me3C6H2 (Mes) (3a)), are readily prepared at room temperature by the oxidative insertion of elemental tellurium into the Csp3−Br or −I bond of the α-halopinacolone and by the reaction of ArTeCl3 with the pinacolone t-BuCOCH3. The bromides Np(t-BuCOCH2)TeBr2 (2b) and Mes(t-BuCOCH2)TeBr2 (3b) can be prepared by the addition of bromine to the telluride Ar(t-BuCOCH2)Te or of α-bromopinacolone to ArTeBr. Variable-temperature 1H and 13C NMR of the separate signals for the o-Me groups in 3a,b indicate a very high barrier to rotation about the Te−C(aryl) bond. Crystal diffraction data for 1c, 2a−c, and 3b show that intramolecular 1,4-Te···O(C) secondary bonding interactions (SBIs) are retained even in the presence of bulky aryl groups and intermolecular Te···X SBIs are subject to electronic population and steric congestion around the Te(IV) center in the solid state.

1-Naphthyl- and mesityltellurium(IV, II) derivatives of small bite chelating organic ligands: Effect of steric bulk and intramolecular secondary bonding interaction on molecular geometry and supramolecular association

The synthesis and characterization of unsymmetric diorganotellurium compounds containing a sterically demanding 1-naphthyl or mesityl ligand and a small bite chelating organic ligand capable of 1,4-Te⋯N(O) intramolecular interaction is described. The reaction of ArTeCl 3 (Ar = 1-C 10H 7, Np; 2,4,6-Me 3C 6H 2, Mes) with (SB)HgCl [SB = the Schiff base, 2-(4,4′-NO 2C 6H 4CH NC 6H 3-Me)] or a methyl ketone (RCOCH 3) afforded the corresponding dichlorides (SB)ArTeCl 2 (Ar = Np, 1Aa; Mes, 1Ba) or (RCOCH 2)ArTeCl 2 (Ar = Np; R = Ph ( 2Aa), Me ( 3Aa), Np ( 4Aa); Ar = Mes, R = Ph ( 2Ba)). Reduction of 1Aa and 1Ba by Na 2S 2O 5 readily gave the tellurides (SB)ArTe (Ar = Np ( 1A), Mes, ( 1B)) but that of dichlorides derived from methylketones was complicated due to partial decomposition to tellurium powder and diarylditelluride (Ar 2Te 2), resulting in poor yields of the corresponding tellurides 2A, 2B and 3A. Oxidation of the isolated tellurides with SO 2Cl 2, Br 2 and I 2 yielded the corresponding dihalides. All the synthesized compounds have been characterized with the help of IR, 1H, 13C, and 125Te NMR and in the case of 2Aa, and 2Ba by X-ray crystallography. Appearance of only one 125Te signal indicated that the unsymmetric derivatives were stable to disproportionation to symmetric species. Intramolecular 1,4-Te⋯O secondary bonding interactions (SBIs) are exhibited in the crystal structures of both the tellurium(IV) dichlorides, 2Aa, and 2Ba. Steric repulsion of the mesityl group in the latter dominates over lone pair–bond pair repulsion, resulting in significant widening of the equatorial C–Te–C angle. This appears to be responsible for the lack of Te⋯Cl involved supramolecular associations in the crystal structure of 2Ba.

Secondary Bonding Interactions Observed in Two Arsenic Thiolate Complexes

Treatment of N-(2-mercaptoethyl)-1,8-naphthalimide (HL) with stoichiometric amounts of AsCl(3) and base affords AsL(2)Cl and AsL(3) complexes stabilized in part by secondary As...O bonding interactions.

The Effect of Steric Hindrance on the Association of Telluradiazoles through Te−N Secondary Bonding Interactions

DFT calculations were used to compare the magnitude of steric repulsion to the strength of secondary bonding interactions (SBIs) in the (Te−N)2 supramolecular synthon to explain or predict the supramolecular structures assembled by two derivatives of the 1,2,5-telluradiazole ring: benzo-2,1,3-telluradiazole (4c) and 3,6-dibromobenzo-2,1,3-telluradiazole (5). The crystallographically determined structures were consistent with the computational predictions. In sharp contrast with the previously known structures of its sulfur and selenium analogues, 4c forms infinite ribbon chains in the solid state with 2.682(7)−2.720(7) Å Te−N SBIs. Steric hindrance in 5 restricted the supramolecular association to form discrete dimers with 2.697(8) Å Te−N SBIs. In addition to discrete dimers, the dibromo derivative crystallizes as solvated dimers in 5·DMSO with 2.834(5) Å Te−O SBIs. Other weaker SBIs were identified in the crystal lattices and were assessed by the computational method.

Hydrothermal Syntheses, Supramolecular Structures and the Third‐order Non‐linear Optical Properties of Three Copper (I) Halide Amine Complexes Connected via Secondary Bonding Interactions

AbstractThe hydrothermal reactions of Cul, KI and bidentate amines [1, 10‐phenanthroline (phen) or ethylenediamine (en)] gave the three copper (I) halide compounds, Cu3I3 (phen)2 (1), CuI (phen)2 (2) and [Cu (en)2] [CuI2]2 (3), which were structurally characterized via single‐crystal X‐ray diffraction studies. Hydrogen bonds and τ‐τ interactions are the most remarkable structural features of the title compounds. All can be described as higher‐dimensional supramolecular compounds connected via these secondary bondings. Moreover, the title compounds were characterized by elemental analyses, IR spectra and TGA analyses. The third‐order non‐linear optical properties of the title compounds were also investigated and all exhibit nicer non‐linear absorption and self‐focusing performance.