Shu-Yan Yu

Self-Assembly of Nanometer-Sized Macrotricyclic Complexes from Ten Small Component Molecules

Nanometer-sized bowls: six metal centers and four tridentate ligands self-assemble in aqueous solution to give the macrotricycle 1, which has approximate dimensions of 3×2×2 nm. Another macrocycle (not shown), obtained with a different ligand, is of similar size and topology but differs considerably from 1 in its host-guest behavior.

From {AuI···AuI}-Coupled Cages to the Cage-Built 2-D {AuI···AuI} Arrays: AuI···AuI Bonding Interaction Driven Self-Assembly and Their AgI Sensing and Photo-Switchable Behavior

Metal-metal bonding interactions have been used to generate a number of unique supramolecular assemblies with fascinating functions. We presented here a new class of gold(I)-containing metallosupramolecular cages and cage-built two-dimensional (2-D) arrays of {Au8L2}n (n = 1 or ∞, L = tetrakis-dithiocarbamato-calix[4]arene, TDCC), 1-3, which are constructed from the self-assembly of deep-cavitand calix[4]arene-based supramolecular cages consisting of octanuclear Au(I) motifs. Synchrotron radiation X-ray diffraction structural analyses of 1-3 revealed their quadruple-stranded helicate dimeric cage structure and the presence of 2-D arrays of cages linked together by inter- and intramolecular Au(I)···Au(I) interactions. Electronic absorption and emission studies of complexes 1-3 indicated the occurrence of a programmable self-assembly process in a concentration-dependent stepwise manner with the links built via aurophilic interactions. These novel gold(I) supramolecular cages exhibited green phosphorescence and have been shown to serve as highly selective proof-of-concept luminescent sensors toward Ag(I) cation among various competitive transition-metal ions.

Self-Assembly and Host−Guest Interaction of Metallomacrocycles Using Fluorescent Dipyrazole Linker with Dimetallic Clips

By employing diimine ligands coordinated dimetallic clips ([(bpy)2Pd2(NO3)2](NO3)2 or [(phen)2Pd2(NO3)2](NO3)2, where bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) as the corner and anthracene-, naphthalene-, and benzene-based dipyrazolate dianions as the linker, a series of positively charged metallomacrocycles ([M4L2]4+ or [M8L4]8+) have been synthesized through a directed self-assembly method in aqueous solution. Every macrocycle has a cavity to bind solvent molecules or anions. The structures were characterized by elemental analysis, 1H and 13C NMR, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analysis for compound 1 x 4 PF6(-) (1 = {[(bpy)Pd]4L(1)2}4+), 3 x 4 PF6(-) x 8 CH3CN x H2O (3 = {[(bpy)Pd]4L(2)2}4+), and 7 x 4 PF6(-) x 6 H2O (7 = {[(bpy)Pd]4L(5)2}4+). The 1:1 host-guest complexation for anthracene-based dipyrazolate-bridged macrocycles with aromatic guests was investigated via UV-vis and fluorescent titration.

Synthesis and Anion Sensing of Water-Soluble Metallomacrocycles

The self-assembly of (TMEDA)Pd(NO(3))(2) or (TMEDA)Pt(NO(3))(2) (where TMEDA = N(1),N(1),N(2),N(2)-tetramethylethane-1,2-diamine) and anthracene- or ferrocene-based diimidazole ligands (L(1-3)) in aqueous solution affords a series of positively charged [M(2)L(2)](4+) dimetallomacrocycles. Their structures were characterized by (1)H NMR and electrospray ionization mass spectrometry and in the cases of {[(TMEDA)Pd](2)L(1)(2)}(NO(3))(4) (1), {[(TMEDA)Pd](2)L(1)(2)}(PF(6))(4) (1a), and {[(TMEDA)Pd](2)L(3)(2)}(NO(3))(4) (4) by single-crystal X-ray diffraction analysis. Interestingly, the NMR spectra of 1 and 1a revealed that the difference of their structures, as confirmed by X-ray diffraction analysis, was that a NO(3)(-) of 1 was encapsulated inside the cavity of the basket-shaped metallomacrocycle by C-H···O hydrogen bonds, while PF(6)(-) of 1a was bound outside by C-H···F hydrogen bonds. The fluorescence titration experiment exhibited the formation of 1:1 host-guest complexation for anthracene-based positively charged [M(2)L(2)](4+)-type metallomacrocycles with NO(3)(-). The interactions between metallomacrocycles and various anions were investigated via fluorescence titration and cyclic voltammetry studies, respectively.

Self-assembly of a neutral luminescent Au12 cluster with D2 symmetry

The preparation and characterization of luminescent neutral Au(12) shuttle-like complexes is reported which shows a cyclic framework consisting of twelve gold(i) ions arranged in a closed ring via non-covalent Au(i)Au(i) interactions to give a chiral D(2) symmetrical structure.

Fine‐Tuning Conformational Motion of a Self‐Assembled Metal–Organic Macrocycle by Multiple CH⋅⋅⋅Anion Hydrogen Bonds

Biological molecular motor proteins that exist ubiquitously in nature have inspired the design of supramolecular systems of controllable motions, for example, rotation, shuttling, and folding. Based on these motions, artificial molecular devices and machines have been intensively developed, which are controlled with external stimuli, such as metal-cation coordination, chemical reaction, redox processes, and light sensitivity. Recently, artificial molecular devices driven by anions in organic host systems have received increasing interest because the anion species play important roles both in environmental and biological processes. 11] In contrast, metal–organic self-assembled systems employed to construct anion controlled molecular devices have rarely been reported to date. Herein, we present a novel anion-switchable selfassembled metal–organic macrocyclic system, the conformation of which can be directly controlled by C H···anion hydrogen bonding (Scheme 1). Furthermore, the conformations and the transformation process of two relatively stable states have been observed both in solution by NOESY and ESI-MS and in the solid state by X-ray crystallographic analysis. The metal–organic macrocycle was synthesized from the reaction of a palladium(II) nitrate prescursor with di(1Hnaphtho[2,3-d]imidazol-1-yl)methane (L), which contains two naphthoimidazole units linked with a methylene bridge and exists as two stable conformations (cis and trans ; Scheme 1). Treating L with one equivalent of [(tmen)Pd(NO3)2] (tmen = N,N,N’,N’-tetramethylethylenediamine) in H2O/acetone (1:1 v/v) at 60 8C for 2 h, the complex 1a·4 NO3 ([M2L2]·4 NO3 , where M = {(tmen)Pd}) with a fixed bowl-shaped conformation was formed in quantitative yield. Subsequent addition of an excess of sodium tetraphenylborate to the solution of 1a·4 NO3 in H2O/acetonitrile (1:1 v/v) afforded complex 1b·4 BPh4 with a freed partial-chair conformation. Similarly, 1b·4 PF6 was obtained by stirring the complex of nitrate in aqueous ammonium hexafluorophosphate. In the H NMR spectrum of 1a·4 NO3 in D2O/ [D6]acetone (1:1 v/v), the signals of the methylene bridge protons of L (d = 7.19, 6.92 ppm) split into a pair of doublets (Supporting Information, Figure S2). The diastereotopic environment of the methylene bridges protons cannot be averaged, which suggests a highly symmetric structure. Furthermore, the four methyl groups on the tmen units also split into two groups of singlets, and three pairs of peaks with chemical shift values between d = 7.30 and 9.35 ppm can be assigned to the aromatic protons on the naphthanoimidazolium moieties. The results imply that the complex 1a·4NO3 keeps a fixed cone conformation in solution at room temperature. The ESI-MS measurements of 1a·4 NO3 confirmed the existence of the cationic macrocycle 1 in methanol solution. Three intense peaks were observed at m/z = 285, 401, and 632 corresponding to the cations [1a], [1a·NO3 ], and [1a·2 NO3 ], respectively (Supporting Information, Figure S28). This is in accordance with the results from a solution study and X-ray crystallography study shown below. Scheme 1. Self-assembly of complex 1a, and the conformational motion between 1a and 1b (free anions and solvent molecules were omitted for clarity).

Self-assembly of bowl-like trinuclear metallo-macrocycles

By employing different diimine complexes and a naphthanoimidazolate (L(1)) or benzoimidazolate (L(2)) anion ligand as linker, a series of trimetallo-macrocycles have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the ligands in aqueous solution. Some compounds, namely, [M(3)L(3)](NO(3))(3) (M = (18-crown-6-phen)Pt, 1 or 7; (15-crown-5-phen)Pt, 2; (benzo-24-crown-8-phen)Pt, 8; (benzo-24-crown-8-phen)Pd, 9; (15-crown-5-phen)Pd, 4 or 11; (18-crown-6-phen)Pd, 3 or 10; (dmbpy)Pd, 6 or 14; (bpy)Pd, 5 or 13; (bpy)Pt, 12; (N4-Phen)Pd, 15) were synthesized. In all of these compounds, the L(1)or L(2) anion ligands are in a syn, syn, syn orientation which result in a bowl-like cavity that can serve as a host to bind the methyl of a solvent CH(3)CN within the naphthanoimidazolate or benzoimidazolate-built cavity through C-H...pi hydrogen bonds in the crystal state. The structures are characterized by elemental analysis, (1)H NMR, ESI-MS, and in the cases of 4a, 11, 13, and 14a by single-crystal X-ray diffraction analysis.

Synthesis and crystal structure of the cryptate complex [Gd(L) (DMF)] · KSCN · CH3CN · 3H20 (L is a deprotonated phenol-based N803 cryptand)

The cryptate complex [Gd(L)(DMF)]. KSCN . CH3CN . 3H(2)O has been synthesized by the reaction of gadolinium isothiocyanate and potassium thiocyanate with cryptate [Na(H(2)L)], which was prepared by a (2+3) Schiff-base condensation of tris(2-aminoethyl)amine and 2,6-diformyl-4-methoxyphenol in the presence of NaOH. The Gd atom is encapsulated in the cryptand with an unsymmetric eight-coordinate environment. Copyright (C) 1996 Elsevier Science Ltd

Synthesis of two heterobimetallic complexes (dppe)PdMS4 (M = W, Mo), and X-ray structure of the tungsten complex

Abstract The heterobimetallic complexes (dppe)PdMS4 [dppe = (CH2PPh2)2, M  W, Mo] have been synthesized by the reaction of (dppe)PdC12 and (NH4)2MS4 in CH2Cl2CH3CN solvent, and characterized by elemental analysis, UV-vis and IR spectroscopies. The structure of (dppe)PdWS4 has been determined by single-crystal X-ray analysis. The Pd-W distance is 2.89 A, the average distance of the W-S bridge is 2.23 A, and that of terminal WS is 2.14 A.

Synthesis and NMR studies of silver complexes with octaaza Schiff-base cryptands and the structure of a polymeric silver cryptate

Abstract Four binuclear and one polymeric silver of octaaza Schiff-base cryptands were synthesized by [2+3] condensation of tris(3-aminopropyl)amine (trpn) or tris(2-aminoethyl)amine (tren) with 5-R-2-methoxyl-1,3-benzenedicarboxaldehyde (R = OCH3, CH3, Br or Ph) in the presence of excess of AgI ion. The polynucleating and extended coordination nature of the trpn-derived cryptand L1 (R = OCH3) was established by X-ray structure of [{Ag(Ag2L1)}n][(ClO4)3·2CH3CN·CH3OH·2 H2On. The polymeric cation [{Ag(Ag2L1)}n] can be described as the bridge-twisted binuclear (Ag2L1) units linked together by silver atoms via a linear NAgN bridging bonding mode in alternate (inward, outward) conformations relative to the benzene rings, resulting in an infinite single helical chain. The benzene rings in the helix chain are almost parallel to each other, with a π-π stacking distance of 3.84 A. The coordination behaviour of cryptands have also been studied by NMR spectroscopy in solution.