Coordination-Driven Self-Assembly of 2D-Metallamacrocycles Using a New Carbazole-Based Dipyridyl Donor: Synthesis, Characterization, and C-60 Binding Study

A new carbazole-based 90 degrees dipyridyl donor 3,6-di(4-pyridylethynyl)carbazole (L) containing carbazole-ethynyl functionality is synthesized in reasonable yield using the Sonagashira coupling reaction. Multinuclear NMR, electrospray ionization-mass spectrometry (ESI-MS), including single crystal X-ray diffraction analysis characterized this 90 degrees building unit. The stoichiometry combination of L with several Pd(II)/Pt(II)-based 90 degrees acceptors (1a-1d) yielded 2 + 2] self-assembled metallacycles (2a-2d) under mild conditions in quantitative yields 1a = cis-(dppf)Pd(OTf)(2); 1b = cis-(dppf)Pt(OTf)(2); 1c = cis-(tmen)Pd(NO3)(2); 1d = 3,6-bis{trans-Pt(C C) (PEt3)(2)(NO3))carbazole]. All these macrocycles were characterized by various spectroscopic techniques, and the molecular structure of 2a was unambiguously determined by single crystal X-ray diffraction analysis. Incorporation of ethynyl functionality to the carbazole backbone causes the resulted macrocycles (2a-2d) to be pi-electron rich and thereby exhibit strong emission characteristics. The macrocycle 2a has a large internal concave aromatic surface. The fluorescence quenching study suggests that 2a forms a similar to 1:1 complex with C-60 with a high association constant of K-sv = 1.0 X 10(5) M-1

Coordination-Driven Self-Assembly of 2D-Metallamacrocycles Using a New Carbazole-Based Dipyridyl Donor: Synthesis, Characterization, and C₆₀ Binding Study

A new carbazole-based 90° dipyridyl donor 3,6-di­(4-pyridylethynyl)­carbazole (<b>L</b>) containing carbazole-ethynyl functionality is synthesized in reasonable yield using the Sonagashira coupling reaction. Multinuclear NMR, electrospray ionization-mass spectrometry (ESI-MS), including single crystal X-ray diffraction analysis characterized this 90° building unit. The stoichiometry combination of <b>L</b> with several Pd­(II)/Pt­(II)-based 90° acceptors (<b>1a</b>–<b>1d</b>) yielded [2 + 2] self-assembled metallacycles (<b>2a</b>–<b>2d</b>) under mild conditions in quantitative yields [<b>1a</b> = <i>cis</i>-(dppf)­Pd­(OTf)₂; <b>1b</b> = <i>cis</i>-(dppf)­Pt­(OTf)₂; <b>1c</b> = <i>cis</i>-(tmen)­Pd­(NO₃)₂; <b>1d</b> = 3,6-bis­{<i>trans</i>-Pt­(CC)­(PEt₃)₂(NO₃)}­carbazole]. All these macrocycles were characterized by various spectroscopic techniques, and the molecular structure of <b>2a</b> was unambiguously determined by single crystal X-ray diffraction analysis. Incorporation of ethynyl functionality to the carbazole backbone causes the resulted macrocycles (<b>2a</b>–<b>2d</b>) to be π-electron rich and thereby exhibit strong emission characteristics. The macrocycle <b>2a</b> has a large internal concave aromatic surface. The fluorescence quenching study suggests that <b>2a</b> forms a ∼1:1 complex with C₆₀ with a high association constant of <i>K</i>_sv = 1.0 × 10⁵ M^–1

Coordination-Driven Self-Assembly of 2D-Metallamacrocycles Using a New Carbazole-Based Dipyridyl Donor: Synthesis, Characterization, and C₆₀ Binding Study

A new carbazole-based 90° dipyridyl donor 3,6-di­(4-pyridylethynyl)­carbazole (<b>L</b>) containing carbazole-ethynyl functionality is synthesized in reasonable yield using the Sonagashira coupling reaction. Multinuclear NMR, electrospray ionization-mass spectrometry (ESI-MS), including single crystal X-ray diffraction analysis characterized this 90° building unit. The stoichiometry combination of <b>L</b> with several Pd­(II)/Pt­(II)-based 90° acceptors (<b>1a</b>–<b>1d</b>) yielded [2 + 2] self-assembled metallacycles (<b>2a</b>–<b>2d</b>) under mild conditions in quantitative yields [<b>1a</b> = <i>cis</i>-(dppf)­Pd­(OTf)₂; <b>1b</b> = <i>cis</i>-(dppf)­Pt­(OTf)₂; <b>1c</b> = <i>cis</i>-(tmen)­Pd­(NO₃)₂; <b>1d</b> = 3,6-bis­{<i>trans</i>-Pt­(CC)­(PEt₃)₂(NO₃)}­carbazole]. All these macrocycles were characterized by various spectroscopic techniques, and the molecular structure of <b>2a</b> was unambiguously determined by single crystal X-ray diffraction analysis. Incorporation of ethynyl functionality to the carbazole backbone causes the resulted macrocycles (<b>2a</b>–<b>2d</b>) to be π-electron rich and thereby exhibit strong emission characteristics. The macrocycle <b>2a</b> has a large internal concave aromatic surface. The fluorescence quenching study suggests that <b>2a</b> forms a ∼1:1 complex with C₆₀ with a high association constant of <i>K</i>_sv = 1.0 × 10⁵ M^–1

Self-assembled molecular squares containing metal-based donor: synthesis and application in the sensing of nitro-aromatics

Self-assemblies between a linear Pt-based donor and ferrocene- chelated metallic acceptors produced novel heterometallic squares 4 and 5, which show fluorescence quenching upon the addition of nitro-aromatics

Coordination-Driven Self-Assembly of M3L2 Trigonal Cages from Preorganized Metalloligands Incorporating Octahedral Metal Centers and Fluorescent Detection of Nitroaromatics

The design and preparation of novel M3L2 trigonal cages via the coordination-driven self-assembly of preorganized metalloligands containing octahedral aluminum(III), gallium(III), or ruthenium(II) centers is described. When tritopic or dinuclear linear metalloligands and appropriate complementary subunits are employed, M3L2 trigonal-bipyramidal and trigonal-prismatic cages are self-assembled under mild conditions. These three-dimensional cages were characterized with multinuclear NMR spectroscopy (H-1 and P-31) and high-resolution electrospray ionization mass spectrometry. The structure of one such trigonal-prismatic cage, self-assembled from an arene ruthenium metalloligand, was confirmed via single-crystal X-ray crystallography. The fluorescent nature of these prisms, due to the presence of their electron-rich ethynyl functionalities, prompted photophysical studies, which revealed that electron-deficient nitroaromatics are effective quenchers of the cages' emission. Excited-state charge transfer from the prisms to the nitroaromatic substrates can be used as the basis for the development of selective and discriminatory turn-off fluorescent sensors for nitroaromatics

Self-assembled metalla-rectangles bearing azodipyridyl ligands: synthesis, characterization and antitumor activity

Sixteen arene-Ru based molecular-rectangles were self-assembled in high yields by the equimolar mixing of arene-Ru acceptors (Aa-Ad) with various azopyridyl ligands (1,2-di(pyridyl-4yl) diazene (L1), 1,2-bis(pyridin-4-ylmethylene)hydrazine (L2), 1,2-bis(1-(pyridin-4-yl) ethylidene) hydrazine (L3), 1,2-bis(pyridin-4ylmethylene) hydrazine (L4)) in nitromethane-methanol solutions. These new molecular-rectangles were fully characterized by a host of analytical techniques including elemental analysis, H-1 and C-13 NMR and HR-ESI-MS. The solid-state structures of two molecular-rectangles (1b and 4d) were determined by single crystal X-ray diffraction data. UV-visible and fluorescence studies were also carried out for the entire suite of rectangles. As with recent studies of similar arene-Ru complexes, the anti-proliferative activities of these complexes were evaluated against SK-hep-1 (liver cancer) and A-549 (lung cancer) human cancer lines. Additionally, the cellular pharmacology and intracellular localizations in AGS (gastric cancer) human cancer cells were determined for selected complexes (1c, 1d and 4c) by apoptosis and fluorescence microscopy studies. These studies confirm that arene-Ru molecular-rectangles inhibit cell cycle progression to the G0 phase, in contrast to that of cisplatin which arrests cell growth in the G2 phase.close101

A Unique Non-catenane Interlocked Self-Assembled Supramolecular Architecture and Its Photophysical Properties

A novel, interlocked, self-assembled (M₂L₂)₂ molecular architecture was constructed from an arene-Ru acceptor and a 1,4-di(pyridin-4-yl)buta-1,3-diyne donor. Two M₂L₂ units, with cavities of ∼7.21 Å, spontaneously interlock, with one unit encapsulating a twin in a non-catenane fashion. The dimeric host–guest complex thus formed is unique among two-dimensional self-assemblies and is stabilized by π–π interactions between the M₂L₂ units

Electron-Rich Arene–Ruthenium Metalla-architectures Incorporating Tetrapyridyl–Tetrathiafulvene Donor Moieties

A series of arene ruthenium architectures have been prepared from coordination-driven self-assembly using dinuclear <i>p</i>-cymene ruthenium acceptors and π-donating tetratopic tetrapyridyl–tetrathiafulvalene donor ligands. The synthetic strategy, based on a geometric interaction approach, leads to four electroactive metalla-assemblies, <b>1</b>–<b>4</b> (one molecular cube and three metallaplates), that were characterized by NMR, ESI-MS, X-ray diffraction, and cyclic voltammetry. Rationalization of their formation discrepancy was completed by DFT calculations supported by structural features of their constituting TTF and Ru-complex components. Metalla-architectures possessing electron-rich cores (<b>3</b>, <i>cis-</i><b>4</b>, and <i>trans</i>-<b>4</b>) interact strongly with picric acid (PA) to yield cocrystallized products, PA + metalla-assemblies, confirmed by single-crystal X-ray structure analyses