Syntheses, structures, and properties of tetrakis(mu-acetato)dirhodium(II) complexes with axial pyridine nitrogen donor ligands with or without assistance of hydrogen bonds

Eight adducts of Rh2(O2CCH3)4 with axial pyridine derivatives that contain hydrogen-bonding amino and/or steric methyl substituents in the 2- and 6-positions have been prepared and examined by electronic absorption and 1H NMR spectroscopy in solution and by elemental, IR, thermogravimetric, and X-ray diffraction analyses in the solid state. The results indicated that strong hydrogen bonding interactions between Rh2(O2CCH3)4 and axially coordinated pyridine derivatives with a 2- or 6-amino group occur in both solution and the solid state and contribute to the higher thermal stability of the molecular assembly of dirhodium complexes. It was demonstrated that such a combination of coordinate and hydrogen bonds is useful as a building tool in designing and constructing new organic-inorganic hybridized compounds and supramolecular architectures.     

Helical supramolecular assemblies of {2,4,6-[Cp*Rh(E2-1,2-C2B10H10)(NC5H4CH2S)]3(triazine)} (E = S, Se) shaped by Cp*-Toluene-Cp* pi-stacking forces and BH-pyridine hydrogen bonding

Polycarborane-substituted molecules [Cp*Rh{E 2C 2(B 10H 10)}] 3(tpst) [E = S ( 2a), Se ( 2b)] were synthesized and characterized. 2a and 2b form toluene solvates in the solid state showing infinitely connected [( 2a, b)-(toluene)] infinity helices. The chains of these supramolecules are held together by Cp*-toluene-Cp* pi-stacking interactions of two of the three Cp* ligands of the bell-shaped 2a and 2b molecules. Unconventional BH (delta-)-pyridyl (delta+) aromatic hydrogen bonding enforces the bell-shapes of the molecular units, and the Cp* conformations are expected to induce the supramolecular structures.     

Multi-component Hydrogen-bonding Organic Salts Formed from 1-Methylpiperazine with Aromatic Carboxylic Acids: Synthons Cooperation and Crystal Structures

1-Methylpiperazine was employed to crystallize with 2,4-dihydroxybenzoic acid and 1,8-naphthalene acid, affording two multi-component hydrogen-bonding salts [(C₅H₁₄N₂)²⁺·(C₇H₅O₄)_2-·H₂O](1) and [(C₅H₁₄N₂)²⁺(C₁₂H₆O₄)²ˉ·2H₂O](2). These two forms of salts are both monoclinic systems with space group P2₁/c(14). The lattice parameters of salts 1 and 2 are a=1.32666(10) nm, b=0.90527(7) nm, c=1.67107(13) nm, β=103.125(1)° and a=1.4950(2) nm, b=0.75242(15) nm, c=1.6563(3) nm, β=92.834(2)°, respectively. Expected classical hydrogen bonds N―H…O and O―H…O appear in the chargetransfer salts, and asymmetric units of these two forms both contain water molecules which play a significant role in building novel supramolecular architectures. Robust hydrogen-bond interactions between 1-methylpiperazine and aromatic acid provide sufficient driving force to direct the two crystals to three-dimensional structures. Weak interactions C―H…O emerging in salts 1 and 2 further enhance their crystal structures. As a consequence, hydrogen-bonding interactions in these compounds afford diverse 3D net supramolecular architectures. Thermal stability of these compounds was investigated by thermogravimetric analysis(TGA).     

Calix

Chiral calix[4]arene derivatives with four O-(N-acetyl-PhgOMe), (1), (Phg denotes R-phenylglycine), or O-(N-acetyl-LeuOMe) (2) strands have been synthesised. Both compounds exist in chloroform in stable cone conformations with a noncovalently organised cavity at the lower rim that is formed by circular interstrand amidic hydrogen bonds. Such organisation affects both the selectivity and extraction/transport properties of 1 and 2 toward metal cations. Calix[4]arene derivatives with one OCH2COPhgOMe strand (3), two OCH2COPhgOMe strands (5) and with 1,3-OMe-2,4-(O-CH2COPhgOMe) substituents (4) at the lower rim have also been prepared. For 3, a conformation stabilised by a circular hydrogen-bond arrangement is found in chloroform, while 4 exists as a time-averaged C2 conformation with two intramolecular NH ...OCH3 hydrogen bonds. Compound 5 has a unique hydrogen-bonding motif in solution and in the solid state with two three-centred NH-.. O and two OH...O hydrogen bonds at the lower rim. This motif keeps 5 in the flattened cone conformation in chloroform. The X-ray structure analysis of 1 revealed a molecular structure with C2 symmetry; this structure is organised in infinite chains by intra- and intermolecular H bonds. The solid-state and solution structures of the [1-Na]ClO4 complex are identical, C4 symmetric cone conformations.     

Supramolecular hydrogen-bonded liquid crystals

The role of hydrogen-bonding interactions in the formation and/or stabilization of liquid crystalline phases has been recognized in recent years and significant work has been conducted. Following the first and well-established examples of liquid crystal formation through the dimerization of aromatic carboxylic acids, several classes of compounds have been prepared by the interaction of complementary molecules, the liquid crystalline behaviour of which is crucially dependent on the structure of the resulting supramolecular systems. In this review the main classes of liquid crystals prepared through hydrogen-bonding interactions are presented, with the aim of establishing, in the first place, the diversity of organic compounds that can be used as building elements in the process of liquid crystal formation. Rigid-rod anisotropic or amphiphilic-type molecules, appropriately functionalized with recognizable moieties, interact in the melt or in solution and lead to the formation of supramolecular complexes that may exhibit thermotropic liquid crystalline character. Depending on the nature, number and position of the groups able to form hydrogen bonds, a diversity of supramolecular structures, both dimeric and polymeric, have been obtained, affording in turn various liquid crystalline phases. The structure and stability of these hydrogen-bonded supramolecular complexes and their relation to the observed liquid crystalline phases are the main topics of this review.     

Supramolecular hydrogen-bonded liquid crystals

The role of hydrogen-bonding interactions in the formation and/or stabilization of liquid crystalline phases has been recognized in recent years and significant work has been conducted. Following the first and well-established examples of liquid crystal formation through the dimerization of aromatic carboxylic acids, several classes of compounds have been prepared by the interaction of complementary molecules, the liquid crystalline behaviour of which is crucially dependent on the structure of the resulting supramolecular systems. In this review the main classes of liquid crystals prepared through hydrogen-bonding interactions are presented, with the aim of establishing, in the first place, the diversity of organic compounds that can be used as building elements in the process of liquid crystal formation. Rigid-rod anisotropic or amphiphilic-type molecules, appropriately functionalized with recognizable moieties, interact in the melt or in solution and lead to the formation of supramolecular complexes that may exhibit thermotropic liquid crystalline character. Depending on the nature, number and position of the groups able to form hydrogen bonds, a diversity of supramolecular structures, both dimeric and polymeric, have been obtained, affording in turn various liquid crystalline phases. The structure and stability of these hydrogen-bonded supramolecular complexes and their relation to the observed liquid crystalline phases are the main topics of this review.     

Sapphyrin Supramolecules through C−H⋅⋅⋅S and C−H⋅⋅⋅Se Hydrogen Bonds—First Structural Characterization of meso- Arylsapphyrins Bearing Heteroatoms

An unprecedented coupling reaction of heteroatom-containing tripyrranes leads to the formation of core-modified sapphyrins 1 and 2 , which self-assemble in the solid state to form supramolecular ladders. Weak C−H⋅⋅⋅S and C−H⋅⋅⋅Se hydrogen-bonding interactions in addition to C−H⋅⋅⋅N hydrogen bonds are responsible for the observed structures.     

Noncovalent interactions under extreme conditions: high-pressure and low-temperature diffraction studies of the isostructural metal-organic networks (4-chloropyridinium)2[CoX4] (X = Cl, Br)

The crystal structures of the two isostructural metal-organic salts, (4-chloropyridinium) 2[CoX 4], X = Cl ( 1), Br ( 2), have each been determined at nine temperatures from 30 to 300 K and at nine pressures from atmospheric pressure to 4.2 GPa. A 5% reduction in unit cell volume is observed upon temperature reduction, whereas an 18-19% reduction is observed upon increasing the pressure over the ranges studied. The structures adopt a tape arrangement propagated by bifurcated N-H...X 2Co hydrogen bonds and by Co-X...Cl-C halogen bonds. Intertape interactions include type I Co-X...Cl-C and C-Cl...Cl-C halogen-halogen interactions as well as offset pi-stacking between the aromatic rings of the cations. Although little anisotropy in compression is seen upon temperature reduction, marked anisotropy in compression is observed upon pressure increase. Compression between tapes far exceeds compression along the tape, consistent with the strong attractive nature of the intratape N-H...X 2Co and Co-X...Cl-C interactions and the weaker dispersion dominated Co-X...Cl-C and C-Cl...Cl-C halogen-halogen interactions and pi-stacking interactions. Increased distortion of the [CoX 4] (2-) anions from idealized tetrahedral geometry arises upon pressure increase, consistent with local changes in the electric field that result from compression of the pairs of pi-stacked cations. The study of the isostructural pair of compounds permits a rare opportunity for quantitative evaluation of the "internal" or "chemical" pressure exerted by changing the [CoBr 4] (2-) anion for the smaller [CoCl 4] (2-) anion. Thus, crystal structures of 1 and 2 with equivalent unit cell volumes require an additional pressure of ca. 1 GPa exerted upon the structure containing the larger [CoBr 4] (2-) anion ( 2). This internal pressure increases to ca. 1.9 GPa at the highest pressures used in this study. Most significant is that examination of the isovolumetric pairs of structures shows that the structures containing the [CoCl 4] (2-) anion are contracted along the <101> vector, the direction of tape propagation, by ca. 1.2% and correspondingly expanded in other directions, relative to those containing the [CoBr 4] (2-) anion. Since the effect of difference in anion size has been removed by application of pressure, this anisotropy in dimensions clearly indicates that the N-H...X 2Co hydrogen bonds and Co-X...Cl-C halogen bonds are more strongly attractive for X = Cl rather than X = Br. Use of internal pressure thereby provides unique insight into the relative strength of intermolecular interactions.     

Gas-phase DNA oligonucleotide structures. A QM/MM and atoms in molecules study

QM/MM calculations have been employed to investigate the role of hydrogen bonding and pi-stacking in single- and double-stranded DNA oligonucleotides. DFT calculations and Atoms in Molecules analysis on QM/MM-optimized structures allow characterization and estimation of the energies of pi-stacking and hydrogen-bond interactions. This shows that pi-stacking interactions depend on the number and the nature of the DNA bases for single-stranded nucleotides; for instance, guanines are found to be involved in strong hydrogen bonds, whereas adenines interact mainly via stacking interactions. The role of interbase hydrogen bonding was explored: the -NH2 groups of guanine, adenine, and cytosine participate in N-H...O and N-H...N interactions. These are much stronger in single-strand oligonucleotides, where the -NH2 groups are highly nonplanar. In double-stranded DNA, the strong base-pairing hydrogen bonds of complementary bases lead to more planar -NH2 groups, which tend to be involved in pi-stacking interactions rather than H-bonds. The use of AIM also allows us to evaluate the interplay of pi-stacking and H-bonding, suggesting that cooperativity does occur, but is generally limited to about 1-2 kcal/mol.     

Novel polyoxometalate-templated, 3-D supramolecular networks based on lanthanide dimers: synthesis,structure, and fluorescent properties of [Ln2(DNBA)4(DMF)8][Mo6O19] (DNBA = 3,5-dinitrobenzoate)

The spherical Lindquist type polyoxometalate, Mo(6)O(19)(2)(-), has been used as a noncoordinating anionic template for the construction of novel three-dimensional lanthanide-aromatic monocarboxylate dimer supramolecular networks [Ln(2)(DNBA)(4)(DMF)(8)][Mo(6)O(19)] (Ln = La 1, Ce 2, and Eu 3, DNBA = 3,5-dinitrobenzoate, DMF = dimethylformamide). The title compounds are characterized by elemental analyses, IR, and single-crystal X-ray diffractions. X-ray diffraction experiments reveal that two Ln(III) ions are bridged by four 3,5-dinitrobenzoate anions as asymmetrically bridging ligands, leading to dimeric cores, [Ln(2)(DNBA)(4)(DMF)(8)](2+); [Ln(2)(DNBA)(4)(DMF)(8)](2+) groups are joined together by pi-pi stacking interactions between the aromatic groups to form a two-dimensional grid-like network; the 2-D supramolecular layers are further extended into 3-D supramolecular networks with 1-D box-like channels by hydrogen-bonding interactions, in which hexamolybdate polyanions reside. The compounds represent the first examples of 3-D carboxylate-bridged lanthanide dimer supramolecular "host" networks formed by pi-pi stacking and hydrogen-bonding interactions encapsulating noncoordinating "guest" polyoxoanion species. The fluorescent activity of compound 3 is reported.     

Unzipping Nucleoside Channels by Means of Alcohol Disassembly

Gold nanoparticles capped with simple adenosine derivatives can form colloidal aggregates in nonpolar solvents. Theoretical calculations indicate the formation of organic channels by the supramolecular assembly of the nanoparticles by means of hydrogen bonds between the adenine moieties. The aggregates were only negligibly sensitive to nPrOH, iPrOH, and tBuOH, whereas some showed a similar response to MeOH and EtOH, and others showed high selectivity toward MeOH. DNA nucleoside derivatives (1‐(2‐deoxy‐β‐D ‐ribofuranosyl)‐5‐methyluracil and 2′,3′‐O‐isopropylideneadenosine) as well as thymine and other aromatic compounds such as pyrene derivatives (pyrene, 1‐chloropyrene, 1‐hydroxypyrene, (1‐pyrenyl)methanol, and 2‐hydroxynapthalene) did not induce disassembly of the nanoparticle aggregates. Data suggest that the nucleoside channels allow access to alcohols according to their size, and an efficient interaction between the alcohol and the adenine units destabilizes the hydrogen bonds, which eventually leads to nanoparticle disassembly.     

Hydrogen-bond mediation of supramolecular aggregation in neutral bis-(C6F5)Pt complexes with aromatic H-bond donating ligands. A synthetic and structural study

Six pentafluorophenylplatinum(II) complexes containing proton acceptor atoms (F) and pyridine-like aromatic ligands able to act as proton donors have been synthesized and characterized, with emphasis on the factors that mediate their supramolecular aggregation in the solid state--hydrogen bonds and pi-pi interactions. The crystal structure analyses of the mononuclear complexes cis-[Pt(C6F5)2(napy)](1), cis-[Pt(C6F5)2(CH2napy)](3), cis-[Pt(C6F5)2(2-ammpy)](5), and cis-[Pt(C6F5)2(2-bipym)](6) reveal the influence of D-HPt and D-HF (D=C, N) hydrogen bonding on the organization of molecules into stacks, which can be further interconnected to generate channels. The prevalence of hydrogen bonding over pi-pi interactions between aromatic rings in establishing the nature of the observed supramolecular aggregation is demonstrated.     

First systematic investigation of C-H...Cl hydrogen bonding using inorganic supramolecular synthons: lamellar, stitched stair-case, linked-ladder, and helical structures

Using a group of six neutral M(II)Cl(2)-containing coordination compounds as building blocks, the first systematic investigation of C-H...Cl hydrogen-bonding interactions was performed. Single-crystal X-ray structural analyses of four new compounds (pseudo-tetrahedral Co(II) and Zn(II); distorted trigonal bipyramidal Zn(II)) authenticate the metal coordination geometry. To provide a unified view of the presence of noncovalent interactions in this class of compounds, we have re-examined the packing diagram of two previously reported compounds (a distorted square-pyramidal Cu(II) complex and a trans-octahedral Co(II) complex). The organic ligands of our choice comprise bidentate/tridentate pyrazolylmethylpyridines and an unsymmetrical tridentate pyridylalkylamine. This systematic investigation has allowed us to demonstrate the existence of versatile C-H...Cl(2)M interactions and to report the successful application of such units as inorganic supramolecular synthons. Additional noncovalent interactions such as C-H...O and O-H...Cl hydrogen bonding and pi-pi stacking interactions have also been identified. Formation of novel supramolecular architectures has been revealed: 2D lamellar (p-cyclophane) and 3D lamellar, 3D "stitched staircase" (due to additional hydrogen-bonding interactions by water tetramers, with an average O-O bond length in the tetramer unit of 2.926 A, acting as "molecular clips" between staircases), 3D linked ladder, and single-stranded 1D helix.     

Construction of hydrogen-bonded ternary organic crystals derived from L-tartaric acid and their application to enantioseparation of secondary alcohols

Ternary organic crystals consisting of an L-tartaric acid-derived dicarboxylic acid, a commercially available achiral diamine, and a chiral secondary alcohol have been developed and characterized by X-ray crystallography. 1D, 2D, and 3D hydrogen-bonded supramolecular networks were constructed, depending on the structure of the diamine used. Benzylic and aliphatic secondary alcohols were enantioselectively incorporated into the crystal and were successfully enantioseparated with up to 86 and 79% enantiomeric excess (ee), respectively. Selective incorporation of one enantiomer of 2-butanol, which is a small chiral aliphatic alcohol, was achieved by the cooperative effects of hydrogen bonds, CH···π interactions, and van der Waals interactions between the guest and host molecules, with the aid of two water molecules. The high host potential of the binary supramolecular system is mainly attributed to the skewed conformation of two rigid aromatic groups of tartaric acid derivatives, which prevents dense packing of the molecules and enhances the formation of multicomponent inclusion crystals.     

Hydrogen-bond-directing effect in the ionothermal synthesis of metal coordination polymers

Four new cobalt coordination polymers, (EMIm)[Co2(TMA-H)2(44bpy)3]Br 1, (EMIm)[Co(TMA-H)(44bpy)2](44bpy)Br 2, (EMIm)[Co(TMA)(Im-H)]3 and (EMIm)2[Co(TMA)2(TED-H2)] 4, were prepared from 1-ethyl-3-methyl imidazolium bromide (EMIm-Br). All the compounds have similar two-dimensional cobalt trimesate (TMA) coordination layers but different three-dimensional supramolecular architectures that contain one of three potentially ditopic amines, 4,4'-bipyridine (44bpy), imidazole (Im-H) and triethylenediamine (TED). Two-fold interpenetration of hydrogen-bonding networks was found for 1, 2 and 4. The coordination layers of 1 and 2 are neutral while 3 and 4 have anionic molecular assemblies. The use of organic amines, that act as supramolecular bridging ligands, introduces hydrogen-bond-directing effects in the ionothermal synthesis of metal coordination polymers. Hydrogen bonding helps to align the packing between the coordination layers and control the formation of 3D supramolecular networks. In 1, hydrogen bonds between the ionic species within the channels direct the alignment of non-directional electrostatic interactions between EMIm+ and Br(-) ions, which is a rare case of a hydrogen-bond-templating effect of ionic liquids in ionothermal synthesis.     

Self-Assembly of PEGylated Diphenylalanines into Photoluminescent Fibrillary Aggregates

Diphenylalanine (FF) represents one of the most studied self-assembling peptides. As a consequence of non-covalent interactions (aromatic stacking and hydrogen bonds), FF is able to generate different nanoarchitectures, proposed in the last years as innovative tools for several applications. The identification of the relationship between the chemical building block composition and the supramolecular structure of final material is the objective of intense research. Different FF analogues were synthetized and studied. At the state of art, in the high number of FF derivatives, PEGylation has not been studied yet, notwithstanding its role has been demonstrated for longer poly-phenylalanine peptides. Herein, we describe the synthesis and the supramolecular behavior of two PEGylated-FF derivatives, PEG2-FF and PEG6-FF, in which the zwitterionic FF has been derivatized at the N-terminus with two or six ethoxylic moieties, respectively. Spectroscopic methodologies (fluorescence, circular dichroism, Fourier transform infrared) allowed the identification of their secondary structure and the calculation of the critical aggregation concentration. PEGylation of the dipeptide induces a modification of the conformational organization from nanotubes with hexagonal symmetry to β-sheet rich fibrils. This structural organization confers photoluminescence features to the supramolecular structures.     

Expanding the Hoogsteen edge of 2'-deoxyguanosine: consequences for G-quadruplex formation

[structure: see text] The synthesis and self-assembling properties of 8-aryl-2'-deoxyguanosine derivatives are described. Our studies suggest that a properly placed acetyl group can increase the stability and specificity of the resulting G-quadruplex supramolecules by enhancing noncovalent interactions such as hydrogen bonds and pi-stacking.     

Trans doubly N-confused porphyrins: Cu(III) complexation and formation of rodlike hydrogen-bonding networks

A trans type of doubly N-confused isomer of NCP (trans-N2CP) was synthesized via N-confused fused porphyrin (NcFP). The aromatic feature of trans-N2CP due to 18pi electronic system is contrasted to the weak aromaticity of cis-derivative. The solid-state structure of trans-N2CP exhibits pi-stacking column, while the Cu(III) complex shows 1-D rodlike hydrogen bonding chain comparable with the zigzag hydrogen-bonding chain of cis-derivatives.     

Helically chiral ferrocene peptides containing 1'-aminoferrocene-1-carboxylic acid subunits as turn inducers

We present a detailed structural study of peptide derivatives of 1'-aminoferrocene-1-carboxylic acid (ferrocene amino acid, Fca), one of the simplest organometallic amino acids. Fca was incorporated into di- to pentapeptides with D- and L-alanine residues attached to either the carboxy or amino group, or to both. Crystallographic and spectroscopic studies (circular dicroism (CD), IR, and NMR) of about two dozen compounds were used to gain a detailed insight into their structures in the solid state as well as in solution. Four derivatives were characterized by single-crystal X-ray analysis, namely Boc-Fca-Ala-OMe (16), Boc-Fca-D-Ala-OMe (17), Boc-Fca-beta-Ala-OMe (18), and Boc-Ala-Fca-Ala-Ala-OMe (21) (Boc=tert-butyloxycarbamyl). CD spectroscopy is an extremely useful tool to elucidate the helical chirality of the metallocene core. Unlike in all other known ferrocene peptides, the helical chirality of the ferrocene is governed solely by the chirality of the amino acid attached to the N terminus of Fca. Depending on the degree of substitution of both cyclopentadiene (Cp) rings, different hydrogen-bonding patterns are realized. (1)H NMR and IR spectroscopy, together with the results from X-ray crystallography, give detailed information regarding not only the hydrogen-bonding patterns of the compounds, but also the equilibria between different conformers in solution. Differences in chemical shifts of NH protons in dimethyl sulfoxide ([D(6)]DMSO) and CDCl(3), that is, the variation ratio (vr), is used for the first time as a measure of the hydrogen-bonding strength of individual COHN bonds in ferrocenoyl peptides. In dipeptides with one intramolecular hydrogen bond between the pendant chains, for example, in dipeptide 16, an equilibrium between hydrogen-bonded and open forms is observed, as testified by a vr value of around 0.5. Higher peptides, such as tetrapeptide 21, are able to form two intramolecular hydrogen bonds stabilizing one single conformation in CDCl(3) solution (vr approximately 0). Due to the low barrier of Cp-ring rotation, new and unnatural hydrogen-bonding patterns are emerging. The systematic work described herein lays a solid foundation for the rational design of metallocene peptides with unusual structures and properties.     

Secondary Bonding,C═H…O Hydrogen Bonding Assisted Supramolecular Associations and Charge Transfer (CT) Complexes of Organotelluriums and their Nonlinear Optical Properties

Abstract

A library of supramolecular assemblies of acyclic- and cyclic organotelluriums assisted by intermolecular Te… X (X = Cl, Br, I, O, S) secondary bonds has been synthesized and X-ray characterized. In each case the immediate coordination geometry around the central Te atom is pseudotrigonal bipyramidal in which two methylene carbon atoms (attached to Te) in cyclic organotelluriums and methyl carbon atoms in acyclic organotelluriums and the stereochemically active electron lone pair occupy equatorial positions whereas the axial positions are occupied by halogen, oxygen or sulphur. They exists either as (a) ordered oligomers (trimeric, tetrameric, octameric aggregates) (b) cross linked chains, (c) zig-zag ?2 dimensional ribbons and stairs, and (d) 3-dimensional supramolecular networks. It is observed that the supramolecular associations assisted by Te…O and Te…S secondary bonds are modified whereas those assisted by Te…halogen remain more or less the same vis-à-vis the supramolecular associations present in their precursors in the solid state. The first detection of C─H…O hydrogen bonds in organotellurium compounds has been done and their use in the synthesis of tellurium essential and ligand essential supramolecular assemblies is demonstrated. Tetraorganotelluroxanes obtained by easy and efficient routes represent the examples of cooperative participation of intermolecular and intramolecular Te…O secondary bonds and C─H…O hydrogen bonds. Hypervalent Te─I (formed through n → σ* orbital interactions) bonds in cyclic telluranes act as potential synthons for the formation of CT complexes possessing unusual structures. The utility of organotelluriums in the serendipitous synthesis of the first triphenyl methyl phosphonium salts of [C₄H₈TeI₄]^2? and [TeI₆]^2? anions is shown. The second harmonic generation (SHG) efficiency of some of these new supramolecular assemblies of organotelluriums indicates that the presence of C─H…O hydrogen bonds enhances their non linear optical (NLO) properties.