Three-component Assembly Research Articles

Three-component assembly of a metal–inorganic 3D Co(ii) polymer containing bridging hydrazine

Three-component metal-inorganic assembly of a Co(ii) network representing the first example of a 3D coordination polymer containing a hydrazine bridging ligand, has been synthesized and characterized.

Self‐Assembly of Two‐Component Gels: Stoichiometric Control and Component Selection

Two-component systems capable of self-assembling into soft gel-phase materials are of considerable interest due to their tunability and versatility. This paper investigates two-component gels based on a combination of a L-lysine-based dendron and a rigid diamine spacer (1,4-diaminobenzene or 1,4-diaminocyclohexane). The networked gelator was investigated using thermal measurements, circular dichroism, NMR spectroscopy and small angle neutron scattering (SANS) giving insight into the macroscopic properties, nanostructure and molecular-scale organisation. Surprisingly, all of these techniques confirmed that irrespective of the molar ratio of the components employed, the "solid-like" gel network always consisted of a 1:1 mixture of dendron/diamine. Additionally, the gel network was able to tolerate a significant excess of diamine in the "liquid-like" phase before being disrupted. In the light of this observation, we investigated the ability of the gel network structure to evolve from mixtures of different aromatic diamines present in excess. We found that these two-component gels assembled in a component-selective manner, with the dendron preferentially recognising 1,4-diaminobenzene (>70 %), when similar competitor diamines (1,2- and 1,3-diaminobenzene) are present. Furthermore, NMR relaxation measurements demonstrated that the gel based on 1,4-diaminobenzene was better able to form a selective ternary complex with pyrene than the gel based on 1,4-diaminocyclohexane, indicative of controlled and selective pi-pi interactions within a three-component assembly. As such, the results in this paper demonstrate how component selection processes in two-component gel systems can control hierarchical self-assembly.

Novel Synthesis of Pyrido[2,1-a]isoindoles via a Three-Component Assembly Involving Benzynes

A novel three-component assembly involving benzynes has been developed for the synthesis of pyrido[2,1-a]isoindoles in moderate yields. Reaction conditions have been optimized and the scope of the reaction has been studied. A plausible mechanism has been proposed to account for the three-component reaction.

Programmable Hierarchical Three-Component 2D Assembly at a Liquid−Solid Interface: Recognition, Selection, and Transformation

Recognition and selection are of fundamental importance for the hierarchical assembly of supramolecular systems. Coronene induces the formation of a hydrogen-bonded isophthalic acid supramolecular macrocycle, and this well-defined heterocluster forces, in its turn, DBA1 to form a van der Waals stabilized honeycomb lattice, leading to a three-component 2D crystal containing nine molecules in the unit cell. The recognition and selection events enable efficient error correction and healing in redundant mixtures.

Three-component zipper assembly of photoactive cascade architectures with blue, red and colorless naphthalenediimide donors and acceptors

We report the programmed ("zipper") assembly of photoactive rigid-rod pi-stack architectures composed of blue (b), red (r) and colorless (n) core-substituted naphthalene diimides (NDIs) attached along p-oligophenyl (POP) rods. The design strategy and multistep syntheses of the required NDI-POP conjugates are described first. The activity of the obtained up to three-component cascade architectures is characterized in current-voltage curves, which are analyzed to reveal short circuit currents and fill factors as significant characteristics. With one-component zippers, rNDIs are found to give much higher photocurrents than bNDIs. In two-component zippers, substitution of rNDIs by nNDIs in meaningful positions is shown to give increased photocurrents despite reduced absorption of light. Three-component zippers are shown to provide access to an increased structural complexity for more subtle control of function. Reaching from 0.27 to 0.54, fill factors, a measure for the power generated with light, are found to be most sensitive to the directionality of multicomponent cascade architectures. Overall, these results are in agreement with photoinduced charge separation between rNDI (but not bNDI) acceptors and POP donors followed by directional intrastack electron transfer from rNDI radical anions to nNDI acceptors, that is, the formation of supramolecular cascade n/p-heterojunctions.

Catalytic Enantioselective Alkylative Aldol Reaction: Efficient Multicomponent Assembly of Dialkylzincs, Allenic Esters, and Ketones toward Highly Functionalized δ-Lactones with Tetrasubstituted Chiral Centers

A general catalytic asymmetric alkylative aldol reaction is described as a new entry to the catalytic asymmetric multicomponent reaction (CAMCR). Highly functionalized delta-lactones were produced in the presence of a catalytic amount of the Cu(OAc)2-DIFLUORPHOS complex through three-component assembly of dialkylzincs, allenic esters, and unactivated ketones. This CAMCR constructs two C-C bonds and one tetrasubstituted chiral center simultaneously. Conjugate addition of alkylcopper species to an allenic ester produced highly active copper enolate in situ, and the successive asymmetric aldol addition to ketones followed by lactonization afforded the desired products. The addition of MS4A and Lewis base (Ph2S=O, DMSO, or HMPA) is important for obtaining a high yield, with suppression of the undesired alpha-addition pathway. Control/crossover experiments suggest that the addition of a Lewis base facilitated the retro-aldol reaction of the alpha-adducts (proofreading effect). The ketone and copper enolate generated through the retro-aldol reaction were converted to the desired lactone through the gamma-aldol pathway, which was trapped by irreversible lactone formation.

A Molecular Plug−Socket Connector

A monocationic plug-socket connector that is composed, at the molecular level, of three components, (1) a secondary dialkylammonium center (CH2NH2+CH2), which can play the role of a plug toward dibenzo[24]crown-8 (DB24C8), (2) a rigid and conducting biphenyl spacer, and (3) 1,4-benzo-1,5-naphtho[36]crown-10 (BN36C10), capable of playing the role of a socket toward a 4,4'-bipyridinium dicationic plug, was synthesized and displays the ability to act as a plug-socket connector. The fluorescent signal changes associated with the 1,5-dioxynaphthalene unit of its BN36C10 portion were monitored to investigate the association of this plug-socket connector with the complementary socket and plug compounds. The results indicate that (1) the CH2NH2+CH2 part of the molecular connector can thread DB24C8 in a trivial manner and (2) the BN36C10 ring of the connector can be threaded by a 1,1'-dioctyl-4,4'-bipyridinium ion only after the CH2NH2+CH2 site is occupied by a DB24C8 ring. The two connections of the three-component assembly are shown to be controlled reversibly by acid/base and red/ox external inputs, respectively. The results obtained represent a key step for the design and construction of a self-assembling supramolecular system in which the molecular electron source can be connected to the molecular electron drain by a molecular elongation cable.

Catalytic Multicomponent Reactions for the Synthesis of N-Aryl Trisubstituted Pyrroles

Dirhodium(II) salts efficiently catalyze the three-component assembly reaction of an imine, diazoacetonitrile (DAN), and an activated alkynyl coupling partner to form substituted 1,2-diarylpyrroles in moderate to good yields. The transition-metal-catalyzed decomposition of the diazo compound in the presence of the imine presumably generates a transient azomethine ylide that undergoes cycloaddition with dipolarophiles in a highly convergent manner.

A highly diastereoselective, catalytic three-component assembly reaction for the synthesis of spiropyrrolidinyloxindoles

Spiropyrrolidinyloxindole compounds are synthesized in moderate to excellent yield via a highly diastereoselective Cu(I)-catalysed three-component assembly reaction of an imine, diazo-compound and substituted olefin dipolarophile.

Total Synthesis of the Cytostatic Marine Natural Product Dibromophakellstatin via Three-Component Imidazolidinone Anellation

The tetracyclic pyrrole-imidazole alkaloid dibromophakellstatin from the marine sponge Phakellia mauritiana has been synthesized within seven steps from pyrrole in an 18% overall yield. The key step is a three-component assembly of a tricyclic enamide, a nitrene, and a carbamoyl building block, affording the imidazolidinone ring of dibromophakellstatin in one step. Notably, it is possible to employ the reagent EtO2CNHOTs in a double function as a source of the electrophilic nitrene and of a dipolar carbamoyl component. Use of debrominated precursor dipyrrolopyrazinones leads to much higher anellation yields and allowed us to develop a second generation synthesis. The cytostatic activity of dibromophakellstatin is confirmed.

Fluidic Heterogeneous Microsystems Assembly and Packaging

The nonrobotic fabrication of packaged microsystems that contain nonidentical parts has been accomplished by a directed self-assembly process. The self-assembly process uses geometrical shape recognition to identify different components and subsequent bond formation between liquid solder and metal-coated areas to form mechanical and electrical connections. We applied this concept of shape recognition and subsequent formation of contacts to assemble and package microsystems that contained nonidentical subunits. The self-assembly of three-component assemblies is demonstrated by sequentially adding device segments to the assembly solution including 200-mum-sized light-emitting diodes. Six hundred AlGaInP-GaAs light-emitting diode segments self-assembled onto device carriers in 2min without defects. Encapsulation units self-assembled onto the LED-carrier assemblies to form a three-dimensional (3-D) circuit path to operate the final device. The reported procedure provides a new route to the creation of autonomous heterogeneous microsystems including the realization of autonomous wireless sensor system that requires nonidentical units: CMOS circuitry, Non-CMOS sensor unit for sensing, III-V components for communication, and encapsulation units to form 3-D electrical interconnects. The creation of such systems is being discussed and a proof of concept experiment is being demonstrated

Sequential Pd- and Rh-Catalyzed Three-Component Cyclization with Allenylboronate Platform

[reaction: see text] A novel three-component cyclization using allenylboronate ester is described. A three-component assembly of allenylboronate ester, aryl iodides, and stabilized carbon nucleophiles took place in the presence of palladium catalyst, furnishing functionalized alkenylboronate esters with high regio- and stereoselectivity. A Rh-catalyzed cyclization of the resultant three-component products then afforded interesting carbocyclic frameworks efficiently.

Substituted 1‐Allyl‐2‐allenylbenzenes via Palladium‐Catalyzed Allylallenylation of Benzyne Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Cover Picture: Fabrication of Multicomponent Microsystems by Directed Three-Dimensional Self-Assembly (Adv. Funct. Mater. 5/2005)

Directed three-dimensional self-assembly to assemble and package integrated semiconductor devices is demonstrated by Jacobs and Zheng on p. 732. The self-assembly process uses geometrical shape recognition to identify different components and surface-tension between liquid solder and metal-coated areas to form mechanical and electrical connections.The components (top left) self-assemble in a turbulent flow (center) and form functional multi-component microsystems (bottom right) by sequentially adding parts to the assembly solution. The technique provides, for the first time, a route to enable the realization of three-dimensional heterogeneous microsystems that contain non-identical parts, and connecting them electrically. We have developed a directed self-assembly process for the fabrication of three-dimensional (3D) microsystems that contain non-identical parts and a statistical model that relates the process yield to the process parameters. The self-assembly process uses geometric-shape recognition to identify different components, and surface tension between liquid solder and metal-coated areas to form mechanical and electrical connections. The concept is used to realize self-packaging microsystems that contain non-identical subunits. To enable the realization of microsystems that contain more than two non-identical subunits, sequential self-assembly is introduced, a process that is similar to the formation of heterodimers, heterotrimers, and higher aggregates found in nature, chemistry, and chemical biology. The self-assembly of three-component assemblies is demonstrated by sequentially adding device segments to the assembly solution including two hundred micrometer-sized light-emitting diodes (LEDs) and complementary metal oxide semiconductor (CMOS) integrated circuits. Six hundred AlGaInP/GaAs LED segments self-assembled onto device carriers in two minutes, without defects, and encapsulation units self-assembled onto the LED-carrier assemblies to form a 3D circuit path to operate the final device. The self-assembly process is a well-defined statistical process. The process follows a first-order, non-linear differential equation. The presented model relates the progression of the self-assembly and yield with the process parameters—component population and capture probability—that are defined by the agitation and the component design.

Fabrication of Multicomponent Microsystems by Directed Three-Dimensional Self-Assembly

We have developed a directed self-assembly process for the fabrication of three-dimensional (3D) microsystems that contain non-identical parts and a statistical model that relates the process yield to the process parameters. The self-assembly process uses geometric-shape recognition to identify different components, and surface tension between liquid solder and metal-coated areas to form mechanical and electrical connections. The concept is used to realize self-packaging microsystems that contain non-identical subunits. To enable the realization of microsystems that contain more than two non-identical subunits, sequential self-assembly is introduced, a process that is similar to the formation of heterodimers, heterotrimers, and higher aggregates found in nature, chemistry, and chemical biology. The self-assembly of three-component assemblies is demonstrated by sequentially adding device segments to the assembly solution including two hundred micrometer-sized light-emitting diodes (LEDs) and complementary metal oxide semiconductor (CMOS) integrated circuits. Six hundred AlGaInP/GaAs LED segments self-assembled onto device carriers in two minutes, without defects, and encapsulation units self-assembled onto the LED-carrier assemblies to form a 3D circuit path to operate the final device. The self-assembly process is a well-defined statistical process. The process follows a first-order, non-linear differential equation. The presented model relates the progression of the self-assembly and yield with the process parameters-component population and capture probability-that are defined by the agitation and the component design.

A Convenient Synthesis of α‐Methylene‐γ‐butyrolactones from Allenyl Carbonyl Units Mediated by Mo(CO)6 Through Intramolecular Cyclocarbonylation.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Substituted 1-Allyl-2-allenylbenzenes via Palladium-Catalyzed Allylallenylation of Benzyne Derivatives

An efficient method for the synthesis of 1-allyl-2-allenyl benzenes via palladium-catalyzed three-component assembly of benzynes, allyl chlorides, and allenylstannanes is described. Substituted benzyne precursors la-e undergo three-component assembly with various allylic chlorides 2a-e and allenylstannanes in the presence of Pd(dba) 2 /dppe (5 mol%), and cesium fluoride in acetonitrile at ambient temperature affording 1-allyl-2-allenyl benzenes 4a-k in good to excellent yields. The possible mechanism for the present catalytic reaction is proposed.

Intramolecular Cyclocarbonylation of Cyclopropylidenyl Aldehydes Mediated by Molybdenum Carbonyl Complex.

A novel procedure for the synthesis of cis-bicyclic spirocyclopropanelactones from cyclopropylidenyl aldehydes via the molybdenum-mediated cyclocarbonylation is described. The use of (C 7 H 8 )Mo(CO) 3 with DMSO to promote the reaction results in an efficient and convenient protocol for the three-component assembly in high yields.

A Convenient Synthesis of α-Methylene-γ-butyrolactones from Allenyl Carbonyl Units Mediated by Mo(CO)6 through Intramolecular Cyclocarbonylation

A novel procedure for the synthesis of cis-fused bicyclic alpha-methylene-gamma-butyrolactones from allenyl carbonyl functionalities via the molybdenum-mediated cyclocarbonylation is described. The use of Mo(CO)(6) with DMSO to promote reaction results in an efficient and convenient protocol through the three-component assembly in high yields.

Highly Regio‐ and Stereoselective Acylboration, Acylsilation, and Acylstannation of Allenes Catalyzed by Phosphine‐Free Palladium Complexes: An Efficient Route to a New Class of 2‐Acylallylmetal Reagents.

AbstractFor Abstract see ChemInform Abstract in Full Text.