3D Supramolecular Assembly Research Articles

Effect of Intermolecular Dipole−Dipole Interactions on Interfacial Supramolecular Structures of C3-Symmetric Hexa-peri-hexabenzocoronene Derivatives

Two-dimensional (2D) supramolecular assemblies of a series of novel C(3)-symmetric hexa-peri-hexabenzocoronene (HBC) derivatives bearing different substituents adsorbed on highly oriented pyrolytic graphite were studied by using scanning tunneling microscopy at a solid-liquid interface. It was found that the intermolecular dipole-dipole interactions play a critical role in controlling the interfacial supramolecular assembly of these C(3)-symmetric HBC derivatives at the solid-liquid interface. The HBC molecule bearing three -CF(3) groups could form 2D honeycomb structures because of antiparallel dipole-dipole interactions, whereas HBC molecules bearing three -CN or -NO(2) groups could form hexagonal superstructures because of a special trimeric arrangement induced by dipole-dipole interactions and weak hydrogen bonding interactions ([C-H···NC-] or [C-H···O(2)N-]). Molecular mechanics and dynamics simulations were performed to reveal the physics behind the 2D structures as well as detailed functional group interactions. This work provides an example of how intermolecular dipole-dipole interactions could enable fine control over the self-assembly of disklike π-conjugated molecules.

Electrostatically Controlled Nanostructure of Cationic Porphyrin Diacid on Sulfate/Bisulfate Adlayer at Electrochemical Interface

Two different cationic tetraphenyl porphyrins, one with two carboxyphenyl groups in cis-position and the other in trans-position (cis- and trans-H(4)DCPP(2+)), have been examined to control the structure of their 2D supramolecular assemblies in 0.05 M H(2)SO(4) at electrochemical interfaces. Electrochemical scanning tunneling microscopy (EC-STM) images revealed the formation of supramolecularly organized nanostructures of cis-H(4)DCPP(2+) such as dimer, trimer, and tetramer on the (square root(3) x square root(7)) sulfate/bisulfate adlayer, suggesting the importance of both electrostatic interaction between cationic porphyrin core and sulfate/bisulfate adlayer and the hydrogen bond formation between carboxyl groups of the nearest neighbor cationic porphyrins. Trans-H(4)DCPP(4+) ions were also found to be aligned in the square root(3) direction of the sulfate/bisulfate adlayer. The structure of these cationic porphyrin adlayers was found to depend upon the electrode potential; i.e., when the potential was changed in the negative direction, the (square root(3) x square root(7)) sulfate/bisulfate adlayer disappeared, and no ordered arrays were formed. In contrast, when 0.1 M HClO(4) was used as an electrolyte solution, only a disordered array was observed. The results of the present study indicate that the (square root(3) x square root(7)) sulfate/bisulfate adlayer formed on Au(111) in 0.05 M H(2)SO(4) plays a significant role as a nanorail template in the control of electrostatically assembled diacid porphyrin dicarboxylic acid derivative. In addition, the high-resolution STM clearly distinguished between cis-H(4)DCPP(2+) ion and cis-H(2)DCPP molecule. The cis-H(2)DCPP molecules on Au(111) provided an adlayer structure and an electrochemical behavior which are different from those of cis-H(4)DCPP(2+) ions.

Supramolecular diversity and magnetic properties of novel heterometallic Cu(II)/Cr(III) complexes prepared from copper powder, Reineckes salt and ethylenediamine

Three novel heterometallic complexes [Cu(en) 2Cr(NCS) 4(NH 3) 2][Cr(NCS) 4(NH 3) 2] · 6dmf ( 1), [Cu(en) 2Cr(NCS) 4(NH 3) 2](OAc) ( 2) and [{Cu(en) 2} 3{Cr(NCS) 4(NH 3) 2} 2(NCS) 2](NCS) 2 ( 3) have been synthesized in a one-pot reaction from copper powder, Reineckes salt, NH 4X [X − = OAc − ( 2), NCS − ( 3)] in a dmf ( 1) or CH 3CN ( 2, 3) solution of ethylenediamine (en). X-ray studies showed that 1 and 2 consist of cationic polymeric chains, formed by Cu ( en ) 2 2 + and Cr ( NCS ) 4 ( NH 3 ) 2 - building blocks that bridged through thiocyanate anions. In both complexes, distinct hydrogen bonds are present and serve to increase the dimensionality of the compound from one to two (in 1) or three (in 2). The main structural feature of 3 is the pentanuclear Cu 3Cr 2 cation which is H-bonded with uncoordinated thiocyanate groups generating a 3D supramolecular assembly. The shortest Cu⋯Cr distances are 5.840(1) Å for 1, 5.856(1) and 6.018(3) Å for 2 and 6.009(9) and 6.465(9) Å for 3. Compounds 1 and 2 are essentially paramagnets whereas compound 3 shows a weak antiferromagnetic coupling. The magnetic properties are simulated and discussed in terms of the structural features.

Self‐Assembled Two‐Dimensional Water‐Soluble Dipicolinate Cu/Na Coordination Polymer: Structural Features and Catalytic Activity for the Mild Peroxidative Oxidation of Cycloalkanes in Acid‐Free Medium

AbstractThe new water‐soluble 2D Cu/Na coordination polymer [Cu(μ‐dipic)2{Na2(μ‐H2O)4}]n·2nH2O (1) has been synthesized by self‐assembly in aqueous medium from copper(II) nitrate, dipicolinic acid (H2dipic) and sodium hydroxide in the presence of triethanolamine. It has been characterized by IR spectroscopy, FAB+‐MS, elemental and single‐crystal X‐ray diffraction analyses, the latter featuring a layered 2D metal–organic structure that is extended to a 3D supramolecular assembly by extensive hydrogen bonding between adjacent layers and involving crystallization water molecules. Compound 1 has been shown to act as a catalyst precursor for the peroxidative oxidation of cyclohexane and cyclopentane to the corresponding cyclic ketones and alcohols by aqueous H2O2 in MeCN solution and in the absence of acid additives.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

2D and 3D supramolecular assemblies of double cyclopalladated azobenzenes realized by C–H⋯Cl–Pd, π⋯π and C–H⋯π interactions

The double cyclopalladated complex with azobenzene, μ-[( E)-1,2-diphenyldiazene- C 2,8, N 1,2]-di-[chloro(dimethylsulfoxide)palladium(II)]; (DMSO)PdCl(μ-C 6H 4N NC 6H 4)(DMSO)PdCl ( 1) and its analogous complex with DMF as ancillary ligand, (DMF)PdCl(μ-C 6H 4N NC 6H 4)(DMF)PdCl; μ-[( E)-1,2-diphenyldiazene- C 2,8, N 1,2]-di-[chloro(dimethylformamide)palladium(II)] ( 2a) were synthesized and the function of cyclopalladated moiety in molecular assembling in the solid state is illustrated by their crystal packings. The polymorphism of 2a and 2b is discussed. The crystal structures reveal assemblies with molecular components self-organized by C–H⋯Cl–Pd hydrogen bonds, π⋯π, and C–H⋯π interactions. The double cyclopalladated complexes of azobenzene, with two Pd–Cl moieties participating in the hydrogen bond formation and π-conjugated system involved in the π⋯π or C–H⋯π interactions, represent a new class of building blocks for construction of solid state supramolecular assemblies.

1D & 2D Supramolecular assemblies dominated by crystal structure of Pb(II) oxoanion ( and ) complexes with 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDPT)

The two lead(II) complexes, [Pb(PDPT)(NO3)2] n and [Pb(PDPT)2(ClO4)2EtOH]·CH3OH, PDPT = 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine, have been synthesized and characterized. 1D & 2D supramolecular assemblies of these compounds in the solid state are discussed via covalent and noncovalent donor ··· acceptor interactions.

Two 3D supramolecular architectures from zinc hydrogen aconitate 1D polymers

The reaction of Zn(NO 3) 2 · 3(H 2O) with trans-aconitic acid, in presence of chelating Lewis bases, leads to the formation of the 1D polymers [Zn(N–N)(LH)] · nH 2O, where LH 3 = trans-aconitic acid, 1 : N–N = 1,10-phenanthroline (phen), n = 1, 2 : N–N = 2,2′-bipyridine (bpy), n = 2. 3D supramolecular assemblies are constructed through H-bonding and stacking interactions.

Supramolecular Assemblies and Redox Modulation of Pyromellitic Diimide-Based Cyclophane via Noncovalent Interactions with Naphthol1

This paper reports the electroscopic and electrochemical properties of [2 + 2] pyromellitic diimide-based cyclophane 1 as well as acyclic N,N'-bis(2-methoxybenzyl)pyromellitic diimide 2 and the clathrate compounds formed by 1. Compound 1 was synthesized by direct cyclocondensation. Its structure was determined by an X-ray crystallographic analysis of a single crystal obtained by recrystallization from DMF. The intramolecular charge-transfer interactions of 1 and 2 were characterized by UV/vis spectroscopy and MO calculations. The UV/vis spectra showed that the tail of a longer wavelength absorption of both 1 and 2 reached the visible region. MO calculations (B3LYP/6-31G*) showed that the HOMO and LUMO orbitals of 1 and 2 substantially localize in the xylyl and pyromellitic diimide moieties across the methylene linker, respectively. The X-ray crystallographic analyses demonstrated that single crystals grown from a mixture of 1 and alpha-naphthol and a mixture of 1 and beta-naphthol were the clathrate compounds with 1D and 2D supramolecular assemblies, respectively, which are formed by a combination of hydrogen-bonding and charge-transfer interactions. From the cyclic voltammetry measurements, both 1 and 2 showed reversible reduction processes, and the reduction potential observed at -1.09 V vs Ag/Ag+ for 2 split into two potentials at -1.01 and -1.14 V for 1. The addition of alpha- and beta-naphthol induced a decrease in the potentials due to the diradical anion of 1 and radical anion of 2 by about 80 mV, and their reduction processes were reversible.

Liquid crystal behaviour of ionic allylpalladium complexes containing 2-pyrazolylpyridine as bidentate N, N′-ligand

Two types of Pd-complexes containing the new N, N′-ligands 2-[3-(4-alkyloxyphenyl)pyrazol-1-yl]pyridine (pz Rpy; R = C 6H 4OC n H 2 n+1 , n = 6 (hp), 10 (dp), 12 (ddp), 14 (tdp), 16 (hdp), 18 (odp)) ( 1– 6), namely c-[Pd(Cl) 2(pz Rpy)] ( 7– 10) and c-[Pd(η 3-C 3H 5)(pz Rpy)]BF 4 ( 11– 16), have been synthesised and characterised by different spectroscopic techniques. Those members of the second type containing the largest chains (R = ddp 13, tdp 14, hdp 15, odp 16) have been found to have liquid crystal properties showing smectic A mesophases. By contrast, neither the free ligands pz Rpy nor their related c-[Pd(Cl) 2(pz Rpy)] complexes exhibited mesomorphism. The new synthesised metallomesogens are mononuclear complexes with an unsymmetrical molecular shape as deduced from the X-ray structures of c-[Pd(η 3-C 3H 5)(pz Rpy)]BF 4 (R = hp, 11; dp, 12). Both compounds, which are isostructural, show a distorted square-planar environment on the palladium centres defined by the allyl and the bidentate pz Rpy ligands. The crystal structure reveals that both the counteranion and the pz Rpy ligand function as a source of hydrogen-bonding and intermolecular π⋯π contacts resulting in a 2D supramolecular assembly.

Programming Supramolecular Assembly and Chirality in Two-Dimensional Dicarboxylate Networks on a Cu(100) Surface

We report a comparative study on the 2D self-assembly of two related ditopic benzoic acid species, which have similar shape and endgroups but different backbone symmetry. High-resolution scanning tunneling microscopy data reveal how the symmetry information of molecular building blocks is readily expressed in the resulting chiral or nonchiral supramolecular networks. The underlying square Cu(100) surface steers network orientation and accounts for carboxylate formation, resulting in an unusual intermolecular hydrogen bond motif. Our results demonstrate that symmetry and chiral resolution in 2D supramolecular assembly can be controlled via the design of functional molecules and choice of substrate.

Synthesis, crystal structure, and thermal property of a novel supramolecular assembly: (NH4)2(C8H10N4O2)4[H4V10O28]·2H2O, constructed from decavanadate and caffeine

A novel 3D supramolecular assembly constructed from decavanadate and caffeine building blocks, (NH4)2(C8H10N4O2)4[H4V10O28]·2H2O (1), has been synthesized in aqueous solution and characterized by elemental analysis, IR, 1H NMR, 51V NMR, TG-DTA, and single crystal X-Ray diffraction. The compound 1 crystallizes in monoclinic system, space groupP2 1/n, a = 15.801(1) A, b = 12.914(1) A, c = 15.913(2) A, β = 113.55°,V = 2976.4 (5)A3, Z = 2, R = 0.0498 with 6818 reflections. Water molecules, ammonium ions, and caffeine act as “cement” linking the polyanions into 1D chain along the c-axis by hydrogen bonding. In compound 1, extensive hydrogen-bond contacts and strong π–π interactions lead to an ordered 3D supramolecular framework. TG-DTA curves indicate that the weight loss of the complex can be divided into three stages.