Dimeric Supramolecular Structure Research Articles

Direct Extraction of Sodium Hydroxide by Calix[4]pyrrole-Based Ion-Pair Receptors.

Described in this work are calix[4]pyrrole-based ion-pair receptors, cis/trans-1 and cis/trans-2, designed for the extraction of sodium hydroxide. An X-ray diffraction analysis of a single crystal of the cis-1·NaOH isomer isolated from a mixture of cis/trans-1 revealed a unique dimeric supramolecular structure. An average dimer in toluene-d8 solution was inferred on the basis of diffusion-ordered spectroscopy (DOSY). Support for the proposed stoichiometry came from density functional theory (DFT) calculations. The structural stability of the dimeric cis-1·NaOH complex in toluene solution was further confirmed by ab initio molecular dynamics (AIMD) simulation with explicit representation of solvent. Under conditions of liquid-liquid extraction (LLE), purified receptors cis- and trans-2 were both found to remove NaOH from a pH 11.01 aqueous source phase into toluene with extraction efficiencies (E%) of 50-60% when used equimolar to NaOH. However, in all cases, precipitation was observed. Complexities associated with precipitation could be avoided by immobilization of the receptors onto a chemically inert poly(styrene) resin by means of solvent impregnation. The use of solvent-impregnated resins (SIRs) eliminated precipitation in solution while retaining the extraction efficiency toward NaOH. This allowed both the pH and salinity of the alkaline source phase to be lowered.

Water-Involved Hydrogen Bonds in Dimeric Supramolecular Structures of Magnesium and Zinc Phthalocyaninato Complexes.

Two dimeric supramolecular structures {MgPc(H2O)·4-methylmorpholine}2—(1) and {ZnPc(H2O)·4-methylmorpholine}2—(2) formed from two molecules of magnesium and zinc aquaphthalocyanines in 4-methylmorpholine solution were revealed by single-crystal X-ray diffraction. Coordinated H2O molecules to the metal center of respective Mg or Zn phthalocyanines oriented face-to-face to form two hydrogen bonds, one of them connecting via O–H···N-azamethine atom to form a dimeric structure in the crystals with ring-to-ring distances of 3.412(3) Å in 1 and 3.403(5) Å in 2, whereas the second hydrogen bonds link the solvent 4-methylpholine molecules to form supramolecular dimeric {MgPc(H2O)·4-methylmorpholine}2—(1) and {ZnPc(H2O)·4-methylmorpholine}2—(2) structures. The interaction of the metal center of MgPc or ZnPc with O atom of the water molecule results its displacement of ∼0.5 Å from the N4-isonodole plane of the phthalocyaninate(2-) macrocycle that adopts a saucer-shape form. To better understand the interactions leading to the existence of the dimeric structures in the crystals, theoretical calculations of dimer stabilization energy composed of two monomers (MgPcH2O and ZnPcH2O), as well as three-dimensional molecular electrostatic potentials, have been performed using the density functional theoretical method. The calculated absorption spectra of both supramolecular monomers and dimers were compared with the experimental ones in 4-methylmorpholine solution. The water axial ligation of MgPc and ZnPc and the formation of the monomeric and dimeric supramolecular structures only slightly change the energy gap between highest occupied molecular orbital and lowest unoccupied molecular orbital levels that is compared with those of the parent MgPc and ZnPc pigments.

Amphiphilic (Phthalocyaninato) (Porphyrinato) Europium Triple-Decker Nanoribbons with Air-Stable Ambipolar OFET Performance.

An amphiphilic mixed (phthalocyaninato) (porphyrinato) europium(III) triple-decker complex [Pc(OPh)8]Eu[Pc(OPh)8]Eu[TP(C≡CCOOH)PP] (1) with potential ambipolar semiconducting HOMO and LUMO energy levels has been designed, synthesized, and characterized. The OFET devices fabricated by quasi-Langmuir-Shäfer (QLS) technique at the air/water interface with nanoparticle morphology display hole mobility of 7.0 × 10(-7) cm(2) V(-1) s(-1) and electron mobility of 7.5 × 10(-7) cm(2) V(-1) s(-1), which reflects its ambipolar semiconducting nature. However, the performance of the devices fabricated via a "phase-transfer" method from n-hexane with one-dimensional nanoribbon morphology was significantly improved by 3-6 orders of magnitude in terms of hole and electron mobilities, 0.11 and 4 × 10(-4) cm(2) V(-1) s(-1), due to the enhanced π-π interaction in the direction perpendicular to the tetrapyrrole rings associated with the formation of a dimeric supramolecular structure building block depending on the intermolecular hydrogen bonding between the neighboring triple-decker molecules in the one-dimensional nanoribbons.

Design, synthesis, and aggregation behavior of sandwich mixed (phthalocyaninato)(porphyrinato) europium triple-deckers: Effect of substituent on tuning the intermolecular interaction

Two new sandwich mixed (phthalocyaninato)(porphyrinato) europium triple-decker (TDMAPP)Eu2[Pc(OPh)8]2 (1) and (TPyP)Eu2[Pc(OPh)8]2 (2) were designed and synthesized. The self-assembled aggregates of 1 and 2 were fabricated by means of a solution-based quasi-Langmuir–Shäfer (QLS) method. Both structures and properties of the aggregates of 1–2 were comparatively studied by UV–vis absorption spectroscopy, atomic force microscopy (AFM), X-ray diffraction (XRD) techniques and current–voltage (I–V) measurements. Experimental results indicated that the molecules of 1 in the self-assembled aggregates adopted a typical J-type (edge-to-edge) aggregation mode, whereas those of 2 took a “face-to-face” conformation and “edge-on” orientation, implying the effect of side-group substituents on tuning the intermolecular stacking. XRD and AFM characterization clearly showed evidence for the formation of highly textured film structures with controlled molecular orientations within the self-assembled aggregates of 1, while a dimeric supramolecular structure was revealed and thus as the building block self-assembles into the target the net-like nanostructures for the aggregates of 2. In addition, the highly ordered film of 1 showed good semiconducting property with a conductivity of ca. 2.35×10−5S·cm−1, which is more than ca. 1 order of magnitude higher than those of 2, closely related to micro-structures and morphology found for the self-assembled aggregates.

Packing forces in dichloridobis(3,5-diphenyl-1H-pyrazole-κN(2))cobalt(II) dichloromethane hemisolvate.

The title compound, [CoCl2(C15H12N2)2]·0.5CH2Cl2, was crystallized from a binary mixture of dichloromethane and hexane and a dimeric supramolecular structure was isolated. The Co(II) centre exhibits a distorted tetrahedral geometry, with two independent pyrazole-based ligands occupying two coordination sites and two chloride ligands occupying the third and fourth coordination sites. The supramolecular structure is supported by complementary hydrogen bonding between the pyrazole NH group and the chloride ligand of an adjacent molecule. This hydrogen-bonding motif yields a ten-membered hydrogen-bonded ring. Density functional theory (DFT) simulations at the PBE/6-311G level of theory were used to probe the solid-state structure. These simulations suggest that the chelate undergoes a degree of conformational distortion from the lowest-energy geometry to allow for optimal hydrogen bonding in the solid state.

Coordination Chemistry in Water of a Free and a Lipase-Embedded Cationic NCN-Pincer Platinum Center with Neutral and Ionic Triarylphosphines

The coordination chemistry in aqueous media was studied for the platinum center of low-molecular-weight cationic NCN-pincer platinum complexes [RC6H2(CH2NMe2)2-3,5-Pt(H2O)-4]+ (R = −(CH2)3P(═O)(OEt)(OC6H4NO2-4) (1(OH2)), H (2(OH2))) as well as of the platinum center of the NCN-pincer platinum cation embedded in the lipase cutinase (cut-1; molecular weight 20 619.3) with various anionic, neutral, and cationic triarylphosphines. A 31P NMR study of the coordination of triarylphosphines to the cationic NCN-pincer platinum center in low-molecular-weight [2(OH2)][OTf] in both D2O and Tris buffer (Tris = tris(hydroxylmethyl)aminomethane) showed that the phosphine–platinum coordination is strongly affected by Tris buffer molecules. Two crystal structures of a NCN-pincer platinum–phosphine and a NCN-pincer platinum–ethanolamine coordination complex with ethanolamine as a functional model of Tris with hydrogen bridges, provoking a dimeric supramolecular structure, confirmed that the coordination observed in solution occurred in the solid state as well. A 31P NMR and ESI-MS study of the lipase cut-1 showed that the coordination of various triarylphosphines to the enzyme-embedded platinum center is affected by the surrounding protein backbone, discriminating between phosphines on the basis of their size and charge. By using 31P NMR spectroscopy and ESI-MS spectrometry, study of the coordination of triarylphosphines to cut-1 was possible, thereby avoiding the need for the application of laborious biochemical procedures. To the best of our knowledge, this is the first example of a study involving the selective binding of organic ligands to the metal center of a semisynthetic metalloprotein, unequivocally demonstrating that the well-established coordination chemistry for small-molecule complexes can be transferred to biological molecules. This initial study allows future explorations in the field of selective protein targeting and identification, as in protein profiling or screening studies.

Solution-processed thin films based on sandwich-type mixed (phthalocyaninato)(porphyrinato) europium triple-deckers: Structures and comparative performances in ammonia sensing

The solution-processed thin films of a series of three sandwich-type mixed (phthalocyaninato)(porphyrinato) europium complexes with different numbers of hydroxyl groups at the meso-substituted phenyl groups of porphyrin ligand 1–3 were prepared by a quasi-Langmuir–Shäfer (QLS) method. Examination by spectroscopic methods revealed that J-type aggregates have been formed with the increasing degree of order of molecular stacking 1<2<3 films. The IR and XRD results reveal that, a dimeric supramolecular structure was formed depending mainly on the π–π interaction between the tetrapyrrole cores of neighboring triple-decker molecules, which, as the building blocks, self-assembled into the target nanostructures through intermolecular hydrogen bonds. Competition and cooperation between the intermolecular π–π interaction and hydrogen bonding for different compounds were revealed to result in thin-film microstructure with a different morphology from nano-grains for 1 and 2 and nano-sheets for 3. An increasing sensitivity to NH3 at varied concentrations in the range of 15–800ppm, follows the order 3<1<2, revealing the effect of film structure/morphology on sensing performance. In particular, excellent sensitivity, nearly complete reversibility and reproducibility to NH3 even at room temperature are obtained for the ultra-thin solution processed films from 2.

Controllable Self-assembly of Sandwich-type Mixed (phthalocyaninato)(porphyrinato) Rare Earth Triple-Decker Complexes

Two novel sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth complexes Tb2[TClPP]2Pc (1) and Tb2[TClPP] Pc2 (2) [Pc = phthalocyaninate, TClPP = meso-tetrakis (4-chlorophenyl) porphyrinate] have been fabricated into nanostructures by a solution-based method. Their self-assembly properties have been comparatively studied by electronic absorption spectroscopy, transmission electron microscope (TEM), X-ray diffraction (XRD) techniques and current–voltage (I–V) measurements. Due to the different number of porphyrin and phthalocyanine ligands interference, the self-assembly of the two molecules results in totally different morphologies in aggregate: one-dimensional (1D) nanoribbon from 1 vs. two-dimensional (2D) nanosheet from 2. The electronic absorption measurements indicated that J-type aggregates have been formed with the increasing red-shifted degree from nanoribbons to nanosheets depending on the competition and cooperation between the inter-molecular π–π interaction and van der Waals for different compounds. Examination by XRD revealed that in the nanostructures of 1 and 2, a dimeric supramolecular structure was formed through an intermolecular π–π interaction and van der Waals between two sandwich-type molecules, which as the building block self-assembles into the target nanostructures. In addition, the nanosheets from 2 were revealed to show excellent semiconducting properties with the conductivity of 3.0 × 10−3 S m−1 in air due to readily π-stacks with adjacent planar molecules enhanced by higher ordered crystalline molecular arrangement.

Helical nano-structures self-assembled from dimethylaminoethyloxy-containing unsymmetrical octakis-substituted phthalocyanine derivatives

The self-assembling properties of metal free unsymmetrical 2,3,9,10,16,17,23-heptakis(butyloxy)-24-mono(dimethylaminoethyloxy)phthalocyanine H2{Pc(OC4H9)7[OC2H4N(CH3)2]} (1) and its zinc complex counterpart Zn{Pc(OC4H9)7[OC2H4N(CH3)2]} (2) in MeOH have been comparatively investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) technique, and IR and UV-vis spectroscopy. Cooperation of the intermolecular hydrogen bonding/Zn–N coordination bonding with π–π interaction between neighboring phthalocyanine molecules due to the presence of one peripheral dimethylaminoethyloxy side chain for 1 and 2 results in nanostructures with different morphology including left- and right-handed helical ribbons, as well as hollow nanotubes for 1 and nanowire bundles for 2. Electronic absorption spectroscopic results reveal the H-aggregate nature in all the nanostructures formed from both compounds 1 and 2, indicating the dominant π–π inter-molecular interaction between phthalocyanine molecules. The IR and X-ray diffraction (XRD) results reveal a dimeric supramolecular structure formed through the intermolecular hydrogen bonding or Zn–N coordination bonding interaction between two molecules, which as the building block further packs into the target nanostructures depending on π–π interaction with the help of hydrogen bonding/Zn–N coordination bonding interaction between the dimeric supramolecular building blocks for 1 and 2. In particular, the morphological evolution of the nanostructures from helical ribbons to nanotubes has been clearly revealed during the self-assembly process of unsymmetrical phthalocyanine compound 1. In addition, the nanostructures self-assembled from both 1 and 2 were revealed to show good semiconducting properties with the conductivity in the range of 2.04 × 10−5 to 1.28 × 10−4 S m−1 in air due to the ordered one-dimensional π–π stacking enhanced by hydrogen bonding/metal–ligand coordination bonding interaction, which increases to 2.41 × 10−2–2.74 × 10−2 S m−1 after chemical doping with iodine.

Structures and properties of 1,8,15,22-tetrasubstituted phthalocyaninato zinc and nickel complexes: Substitution and axially coordination effects study based on density functional theory calculations

On the basis of the density functional theory (DFT) calculation of ZnPc (1), Zn[Pc(alpha-OC(5)H(11))(4)] (2), Ni[Pc(alpha-OC(5)H(11))(4)] (3), and Zn[Pc(alpha-OC(5)H(11))(4)]xH(2)O (4), the effects of non-peripheral substitution, different transition metals, and axial water coordination on the molecular structure, molecular orbital, atomic charge, infrared (IR) spectrum, and electronic absorption spectrum were investigated. The calculation results reveal that bulky 3-pentyloxy groups at the non-peripheral positions of the phthalocyanine ring evince great changes in structure and properties: they deflect the isoindole units, lift the frontier molecular orbitals, alter the atomic charge distribution, shift the bands of IR and electronic absorption spectra, etc. Though the central metal can shorten or lengthen the bond length, its effect on the electronic structure and properties of the phthalocyanine complex is very limited. Axial coordination significantly enhances the non-planarity of the phthalocyanine ring and, thus, alters the electronic structure, which is important for the formation of novel dimeric supramolecular structures through intermolecular hydrogen bonds. In addition, the calculated structures of 3 as well as the simulated IR and electronic absorption spectra of 4 were compared with the experimental data and showed good agreement.

Self-Assembled Nano-Structures of Sandwich-Type Mixed (Phthalocyaninato)(porphyrinato) Rear Earth Complexes. Effect of Porphyrin-Phthalocyanine Ligands on Tuning the Inter-Molecular Interaction

phthalocyanine, porphyrin, sandwich rare earth complex, nanostructure, self-assembly. Abstract. Three novel sandwich-type mixed (phthalocyaninato)(porphyrinato) rear earth complexes, namely Ce(DPP)(Pc)(1), Sm2(DPP)(Pc)2(2) and Sm2(DPP)2(Pc)(3) [Pc = dianion of phthalocyanine, DPP= dianion of 5,15-di(phenyl)porphyrin], have been fabricated into nano-assemblies onto the SiO2 surface by a surface assisted solvent-vapor annealing method. The effect of the number of porphyrin and phthalocyanine ligands on the morphology of self-assembled nanostructures of these double- and triple-decker complexes has been systematically studied. Competition and cooperation between the inter-molecular - interaction, van der Waals, and metal-ligand coordination for different compounds results in nanostructures with different morphology from approximately spherical shape with average size of ~300 nm and ~400 nm for 1 and 2, respectively, nano-rods with aspect ratio (length over width) around 5 for 3, which were characterized by electronic absorption, X-ray diffraction (XRD), and atomic force microscopy (AFM). Electronic absorption spectroscopic results reveal the formation of J-aggregates in the nano-structures and suggest the increasing - interaction in the order of 3, 1, to 2. Examination by XRD reveal that in the nanostructures of compounds 1-3, a dimeric supramolecular structure was formed through an intermolecular - interaction and/or van der Waals between two sandwich-type molecules, which as the building block self-assembles into the target nanostructures.

H2O-Involved Hydrogen Bonds in Pseudo-Double-Decker Supramolecular Structure of 1,8,15,22-Tetrasubstituted Phthalocyaninato Zinc Complex

A novel dimeric supramolecular structure, {Zn[Pc(α-OC5H11)4]·H2O}2, formed from two molecules of 1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato zinc complex was revealed by X-ray single crystal analysis. With the help of the oxygen atom from the alkoxy substituent attached at the nonperipheral position of the phthalocyanine ring, each H2O forms two hydrogen bonds, connecting two phthalocyanine molecules to form a pseudo-double-decker supramolecular structure in the crystals with a ring-to-ring separation of 3.728 A. This, to the best of our knowledge, represents the first example of supramolecular structure formed from phthalocyanine complexes with transition metals via H2O-involved hydrogen bonding interaction. To enhance understanding of the existence of hydrogen bonds in the solid-state crystal structure of this compound, theoretical calculations on the stabilization energy in a system composed of two Zn[Pc(α-OC5H11)4] moieties as well as in the supramolecular structure {Zn[Pc(α-OC5H11)4]·H2O}2 have b...

Morphology Controlled Self-Assembled Nanostructures of Sandwich Mixed (Phthalocyaninato)(Porphyrinato) Europium Triple-Deckers. Effect of Hydrogen Bonding on Tuning the Intermolecular Interaction

A series of five novel sandwich-type mixed (phthalocyaninato)(porphyrinato) europium triple-decker complexes with different numbers of hydroxyl groups at the meso-substituted phenyl groups of porphyrin ligand 1-5 have been designed, synthesized, and characterized. Their self-assembly properties, in particular the effects of the number and positions of hydroxyl groups on the morphology of self-assembled nanostructures of these triple-decker complexes, have been comparatively and systematically studied. Competition and cooperation between the intermolecular pi-pi interaction and hydrogen bonding in the direction perpendicular to the pi-pi interaction direction for different compounds were revealed to result in nanostructures with a different morphology from nanoleafs for 1, nanoribbons for 2, nanosheets for 3, and curved nanosheets for 4 and to spherical shapes for 5. The IR and X-ray diffraction (XRD) results reveal that, in the nanostructures of triple-decker 2 as well as 3-5, a dimeric supramolecular structure was formed through an intermolecular hydrogen bond between two triple-decker molecules, which as the building block self-assembles into the target nanostructures. Electronic absorption spectroscopic results on the self-assembled nanostructures reveal the H-aggregate nature in the nanoleafs and nanoribbons formed from triple-deckers 1 and 2 due to the dominant pi-pi intermolecular interaction between triple-decker molecules, but the J-aggregate nature in the curved nanosheets and spherical shapes of 4 and 5 depending on the dominant hydrogen bonding interaction in cooperation with pi-pi interaction among the triple-decker molecules. Electronic absorption and XRD investigation clearly reveal the decrease in the pi-pi interaction and increase in the hydrogen bonding interaction among triple-decker molecules in the nanostructures along with the increase of hydroxyl number in the order of 1-5. The present result appears to represent the first effort toward realization of controlling and tuning the morphology of self-assembled nanostructures of sandwich tetrapyrrole rare earth complexes through molecular design and synthesis.

Synthesis of a novel uracil-2,6-diaminopyridine-lithocholic acid conjugate that self-assembles into a cyclic dimer

Synthesis and self-association studies of a uracil-2,6-diaminopyridine-lithocholic acid conjugate are described. The dimeric supramolecular structure is characterized by NMR spectroscopic, ESI-MS, and size exclusion chromatographic studies.

(Phthalocyaninato)copper(II) Complexes Fused with Different Numbers of 15‐Crown‐5 Moieties – Synthesis, Spectroscopy, Supramolecular Structures, and the Effects of Substituent Number and Molecular Symmetry

AbstractSymmetrical (phthalocyaninato)copper(II) complexes Cu(Pc′) [Pc′ = Pc(15C5), Pc(opp‐15C5)2, Pc(adj‐15C5)2, Pc(15C5)3; Pc = unsubstituted phthalocyaninate, Pc(15C5) = 2,3‐(15‐crown‐5)phthalocyaninate, Pc(opp‐15C5)2 = 2,3,16,17‐bis(15‐crown‐5)phthalocyaninate, Pc(adj‐15C5)2 = 2,3,9,10‐bis(15‐crown‐5)phthalocyaninate, Pc(15C5)3 = 2,3,9,10,16,17‐tris(15‐crown‐5)phthalocyaninate] (2–5) have been prepared by the reaction of corresponding heteroleptic bis(phthalocyaninato)europium complexes Eu(Pc)(Pc′) [Pc′ = Pc(15C5), Pc(opp‐15C5)2, Pc(adj‐15C5)2, Pc(15C5)3, Pc(15C5)4; Pc = unsubstituted phthalocyaninate] with Cu(OAc)2 in dry dmf at 100 °C. For the purpose of comparative studies, the symmetrical counterparts CuPc (1) and CuPc(15C5)4 [Pc(15C5)4 =2,3,9,10,16,17,24,25‐tetrakis(15‐crown‐5)phthalocyaninate](7) have also been prepared. These monomeric complexes have been characterized by spectroscopic methods in addition to elemental analysis. Having a series of closely related phthalocyanines with a different number and/or disposition of 15‐crown‐5 groups at the peripheral positions, the effects of 15‐crown‐5 substituent number and molecular symmetry on the electronic absorption spectra, infra‐red (IR) spectra, and supramolecular structure formation induced by K+ ions have been investigated. Systematic studies on the formation of dimeric supramolecular structures of the series of monomers 2–6 reveal and confirm the previously proposed two‐step three‐stage process of K+‐induced dimerization of phthalocyanines with three or four 15‐crown‐5 moieties.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2007)

New dimeric supramolecular structure of mixed (phthalocyaninato)(porphyrinato)europium(iii) sandwiches: preparation and spectroscopic characteristicsElectronic supplementary information (ESI) available: experimental and simulated MALDI-TOF mass spectra of 3; IR spectra of 1, SM1, 3 and SM3. See http://www.rsc.org/suppdata/jm/b3/b300529a/

Download options Please wait... Supplementary files Experimental and simulated MALDI-TOF mass spectra for 3; IR spectra of 1, SM1, 3 and SM3 DOC (178K) Article information DOI https://doi.org/10.1039/B300529A Article type Paper Submitted 14 Jan 2003 Accepted 07 Apr 2003 First published 22 Apr 2003 Download Citation J. Mater. Chem., 2003,13, 1333-1339 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions New dimeric supramolecular structure of mixed (phthalocyaninato)(porphyrinato)europium(III) sandwiches: preparation and spectroscopic characteristics M. Bai, M. Bao, C. Ma, D. P. Arnold, M. T. M. Choi, D. K. P. Ng and J. Jiang, J. Mater. Chem., 2003, 13, 1333 DOI: 10.1039/B300529A To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Ming Bai Meng Bao Changqin Ma Dennis P. Arnold Michael T. M. Choi Dennis K. P. Ng Jianzhuang Jiang