James D. Wuest's research while affiliated with Université du Québec à Montréal and other places

Publications (220)

Article
Benzoquinones can undergo reversible reductions and are attractive candidates for use as active materials in green carbon-based batteries. Related compounds of potential utility include 4,4'-diphenoquinones, which have extended quinonoid structures with two carbonyl groups in different rings. Diphenoquinones are a poorly explored class of compounds...
Article
6-Azidotetrazolo[5,1-a]phthalazine (ATPH) is a nitrogen-rich compound of surprisingly broad interest. It is purported to be a natural product, yet it is closely related to substances developed as explosives and is highly polymorphic despite having a nearly planar structure with little flexibility. Seven solid forms of ATPH have been characterized b...
Article
ConspectusPhosphangulene (1) is a hexacyclic triarylphosphine with a distinctive conical shape and other features that allow the compound to be viewed from diverse perspectives and to be embraced by chemists from different parts of the field as a molecule worthy of special attention. In recent work, phosphangulene and its derivatives have proven to...
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For millennia, humans have exploited the special properties of porous materials. Advances in recent years have yielded a new generation of finely structured porous materials that allow processes to be controlled at the molecular level. These materials are built by a strategy of modular construction, using molecular components designed to position t...
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Controlled synthesis of the electroluminescent polymer PFO-MEH-PPV (poly[(9,9-dioctyl-2,7-divinylenefluorenylene)-alt-co-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene)]) provided samples of varying molecular weight (MW) in the range 20–360 kDa, which were characterized by gel-permeation chromatography and light scattering. By incorporating the sampl...
Article
Chemical compounds that exist in multiple crystalline forms are said to exhibit polymorphism. Polymorphs have the same composition, but their structures and properties can vary markedly. In many fields, conditions for crystallizing compounds of interest are screened exhaustively to generate as many polymorphs as possible, from which the most advant...
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The performance of molecule-based thin-film devices such as organic light-emitting diodes, photovoltaic cells, and thin-film transistors depends on the electronic properties of the individual molecular components, as well as on their association to form complex morphologies. Transmission electron microscopy (TEM) can be used to image the morphologi...
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Conjugated polymers are widely used in thin-film organic photovoltaic devices to absorb light and serve as electron donors or acceptors. Small molecular analogues are attractive substitutes because they have fully defined structures, can be purified rigorously, and are typically more soluble and volatile. However, producing active films composed pr...
Article
Melams, which are derivatives of bis(4,6‐diamino‐1,3,5‐triazin‐2‐yl)amine, can form multiple intermolecular N−H⋅⋅⋅N hydrogen bonds and serve as modules for constructing hydrogen‐bonded organic frameworks (HOFs). This work shows that suitably designed melams can crystallize to form open networks in which each molecule engages in over 20 N−H⋅⋅⋅N hydr...
Article
Ordered materials with predictable structures and properties can be made by a modular approach, using molecules designed to interact with neighbors and hold them in predetermined positions. Incorporating 4,6‐diamino‐1,3,5‐triazin‐2‐yl (DAT) groups in modules is an effective way to direct assembly because each DAT group can form multiple N–H···N hyd...
Article
Sixfold phenyl embraces are well-established aromatic interactions that are strong and directional. In addition, functional groups able to participate, such as triphenylmethyl (trityl), are easily incorporated in molecular structures. As a result, embraces offer a possible way to control molecular organization in materials. To test this notion, we...
Article
Phosphangulene (“Phang”) is an analogue of triphenylphosphine with a conical shape and electron-rich aromatic surface that complements the electron-poor surface of fullerenes, both geometrically and electronically. Large molecular surfaces with multiple areas of concavity can be made by grafting units of Phang onto selected cores, using the ability...
Article
Phosphangulene (1) is a hexacyclic triarylphosphine with a distinctive conical shape and an electron-rich aromatic surface that is geometrically and electronically complementary to fullerenes such as C60 and C70. As a result, suitable derivatives of phosphangulene can cocrystallize with fullerenes or even bind them in solution. Surprisingly, previo...
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The distinctive conical shape and electron-rich aromatic surface of phosphangulene (1) and its derivatives offer geometric and electronic complementarity to the convex electron-poor surface of fullerenes such as C60 and C70. In crystals of phosphangulene itself, molecules form π-stacks that are efficiently packed. In contrast, the corresponding oxi...
Article
Phosphangulene (1) has a well-defined hexacyclic structure with a distinctive conical shape and an electron-rich aromatic surface. Molecules of phosphangulene are disposed to crystallize in parallel π-stacks. This preference can be thwarted by adding a single atom and converting phosphangulene into the corresponding oxide (2a), sulfide (2b), and se...
Article
Bis(diaminotriazinyl)-substituted derivatives 1–6 of benzene, pyridine, and pyrazine were made to test the ability of the 4,6-diamino-1,3,5-triazinyl group (DAT) to direct molecular organization by hydrogen bonding. Analysis of the structures of compounds 1–6 by X-ray crystallography revealed that the DAT groups control association by forming hydro...
Article
Suitably designed quinones and quinols are promising modules for the programmed construction of ordered redox-active molecular solids. To explore this potential, we have synthesized compounds 1–4, in which multiple 1,2-benzoquinone and 1,2-quinol units are attached to a triptycene core. The resulting molecules have topologies that disfavor efficien...
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While stainless steel is a broadly used alloy with interesting mechanical properties, its applications in medicine suffers from inherent biocompatibility limitations. An attractive opportunity to improve its performance is to alter its surface, but this has proven challenging. We now show how high range anodization conditions using H2SO4/H2O2 as an...
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1,2,5,6-Naphthalenetetramine (1a), its 1,4,5,8-isomer (2a), and their salts are valuable precursors for synthesizing nitrogen-containing arenes and other targets of interest. We describe how salts of tetramines 1a and 2a can be made from simple protected derivatives of 1,5-naphthalenediamine (2d) by sequences of regioselective dinitration, deprotec...
Article
Various symmetric isomers of [2,2'-bipyridine]dicarbonitrile and [1,10-phenanthroline]dicarbonitrile were crystallized from solution and also deposited as monolayers adsorbed on graphite. The resulting 3D and 2D structures were studied by single-crystal X-ray diffraction (XRD) and scanning tunneling microscopy (STM), respectively. Previous comparis...
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Predictably ordered materials can be constructed by a modular strategy in which properly designed molecular components are positioned in space by reliable interactions. In principle, this approach can be used to control the arrangement of adjacent systems of π-conjugation, thereby creating molecular materials with valuable optoelectronic properties...
Article
Active layers in many thin-film organic photovoltaic devices (OPVs) contain light-absorbing polymers that serve as electron donors, mixed with appropriate electron acceptors. In principle, the polymers can be replaced by small molecules with suitable bandgaps, which offer multiple advantages, including well-defined structures and methods of synthes...
Article
Electrodes in many thin-film optoelectronic devices are made of layers of indium tin oxide (ITO), which are suitably conductive, can be deposited by established methods, and are nearly transparent and colorless. Regrettably, indium is an uncommon element, its price continues to rise steeply, and producing ITO electrodes consumes a large fraction of...
Article
In the fabrication of thin-film electronic device6s such as solar cells, molecular components are often deposited from solution by spin coating. Toxic chlorinated solvents are widely used in this process, and environmentally benign alternatives are desirable. Ideally, these alternatives should be inexpensive, derived from renewable sources, and abl...
Article
Derivatives of 2,1,3-benzothiadiazole (1) are widely used in many areas of science and are particularly valuable as components of active layers in various thin-film optoelectronic devices. Even more effective benzothiadiazoles are likely to result if a deeper understanding of their preferred patterns of molecular association can be acquired. To pro...
Article
2,4-Diamino-1,3,5-triazinyl (DAT) groups are known to form N-H...N hydrogen bonds according to reliable patterns of self-association. In compounds 3a-c, three DAT groups are attached to trigonally-substituted phenyl cores via identical flexible arms. Crystallization of compounds 3a-c produces robust networks in which each molecule is linked to its...
Article
Aromatic C-nitroso compounds (Ar-N═O) and related species have a rich chemical history, and they continue to interest researchers in many fields. Among the most distinctive and puzzling properties of these compounds is their ability to dimerize reversibly to form azodioxy compounds. The present review subjects this intriguing phenomenon to comprehe...
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We describe a simple way to build giant macrocyclic hydrocarbons by the reversible formation of carbon-carbon bonds. Specifically, extended spirobifluorene-substituted derivatives of Wittig's hydrocarbon were synthesized and found to undergo oligomerization, giving the largest hydrocarbon that has been crystallized and characterized by X-ray diffra...
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Full-text available
Many thin-film optoelectronic devices use electrodes made of tin-doped indium oxide (ITO), which is acceptably conductive, as well as virtually transparent and colorless. Regrettably, indium is an uncommon element and its price continues to rise, so it is increasingly important to recover ITO electrodes from devices that are no longer needed. Previ...
Article
Two bis(amidines), 2,2′-bi-2-imidazoline (BI) and fluoflavin (FF), were treated with phosphonic, phosphoric, and sulfonic acids in an effort to produce crystalline salts composed of ions linked by networks of charge-assisted hydrogen bonds. As intended, mixing bis(amidine) BI with 1,4-benzenediphosphonic acid and 1,3,5-benzenetriphosphonic acid yie...
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An emerging strategy for making ordered materials is modular construction, which connects preformed molecular subunits to neighbours through interactions of properly selected reactive sites. This strategy has yielded remarkable materials, including metal-organic frameworks joined by coordinative bonds, supramolecular networks linked by strong non-c...
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Thin-film photovoltaic devices composed of polymers or small molecules have an exciting future as sources of renewable energy because they can be made in large sizes on flexible surfaces by inexpensive techniques of fabrication. Significant progress in developing new molecular photovoltaic materials and device architectures has been achieved in the...
Article
Amidines can be protonated by carboxylic acids to give amidinium carboxylates, and the ions can associate by forming multiple charge-assisted hydrogen bonds according to reliable motifs. Extended hydrogen-bonded networks can be constructed by treating suitable bis(amidines) with acids containing multiple carboxyl groups. To further explore the pote...
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Photovoltaic cells are an established and increasingly important technology for the production of renewable energy. Whereas organic semiconductors of low molecular weight are generally deposited by evaporation under vacuum, films of conjugated polymers are conveniently created from solution using wet processing techniques. For the production of pro...
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The reaction of [Pd(MeCN)(4)](BF(4))(2) with 2,2'-bipyrimidine (bpm) in MeCN-CHCl(3) afforded the title compound, [Pd(C(8)H(6)N(4))(2)](BF(4))(2)·C(2)H(3)N. The asymmetric unit contains two half complexes, with the Pd(II) atoms both lying on a twofold axis. Each metal atom adopts a tetra-hedrally distorted square-planar geometry. In the crystal, [P...
Article
Linear D2h-symmetric bisisophthalic acids 1-2 and related substances have well-defined flattened structures, high affinities for graphite, and strong abilities to engage in specific intermolecular interactions. Their adsorption produces characteristic nanopatterns that reveal how 2D molecular organization can be controlled by reliable interadsorbat...
Article
Linear bisisophthalic acids 1 and 2 and analogous structures are known to be adsorbed on graphite to give nanopatterns that are programmed by the concerted effects of topology and hydrogen bonding. For comparison, we have now studied the corresponding tetraesters 3–7, which have similar topologies and affinities for graphite but cannot form strong...
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Stacking of a chromophoric molecule in the solid state has been altered rationally by the formation of co-crystals, allowing fine control of luminescence.
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Abstract Numerous studies, many based on statistical analyses of structural data from the Cambridge Structural Database (CSD, have highlighted the importance of halogen···aryl interactions. Although the exact value of the binding energy is still a subject of debate, it is generally agreed that such interactions can play an important role in crysta...
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Amino-substituted azines such as aminotriazines have simple planar structures with an affinity for adsorption on graphite. In addition, aminoazines associate predictably with carboxylic acids according to a reliable hydrogen-bonded motif. Together, these properties help predispose aminoazines and alkanecarboxylic acids to cocrystallize and to coads...
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Optimized conditions A) allow an efficient coupling of the protected hydroxylamine (I) with various aryl halides.
Article
The pyridinyl groups of pyridinyl-substituted diaminotriazines 3a,b and 4a,b can bind metals, and the diaminotriazinyl (DAT) groups serve independently to ensure that the resulting complexes can participate in intercomplex hydrogen bonding according to characteristic motifs. As planned, ligands 3a,b and 4a,b form trans square-planar 2:1 complexes w...
Article
Isomeric pyridyl-substituted diaminotriazines 2a–c and elongated analogue 3 are designed to adopt flattened structures with features that favor adsorption on surfaces and participation in multiple intermolecular interactions. In particular, pyridyl and diaminotriazinyl groups have strong affinities for graphite, and both form coplanar hydrogen-bond...
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In the title compound, [PdCl(2)(C(5)H(6)BNO(2))(2)]·2C(2)H(6)OS, the Pd(II) ion is located on an inversion centre and is four-coordinated in a trans square-planar geometry by two chloride ions and two (pyridin-4-yl)boronic acid ligands. The Pd-N and Pd-Cl distances are 2.023 (2) and 2.2977 (7) Å, respectively, and the average N-Pd-Cl angle is 90°....
Article
6-(Pyridin-2-yl)-1,3,5-triazine-2,4-diamine (1), 6-(pyrazin-2-yl)-1,3,5-triazine-2,4-diamine (2), and 6-(pyrimidin-2-yl)-1,3,5-triazine-2,4-diamine (3) incorporate two key structural features: (1) They resemble 2,2′-bipyridine and can therefore be expected to chelate suitable metals; and (2) they simultaneous incorporate diaminotriazinyl (DAT) grou...
Article
Pd-catalyzed coupling of aryl halides with TeocNHOTBS, followed by treatment of the products with TBAF, provides effective access to a wide range of N-arylhydroxylamines by a route that produces stable doubly-protected intermediates and allows the protective groups to be removed under mild conditions that do not cause extensive degradation of the f...
Article
Adding astutely placed methyl groups to hexaphenylbenzene increases molecular weight but simultaneously weakens key C-H···π interactions, thereby leading to decreased enthalpies of sublimation and showing that materials with abnormally weak cohesion can be made by identifying and then obstructing interactions that help control association.
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Btzn (1), an amine-functionalized bi(1,3,5-triazine) 4,4'-(NH(2))(2)-6,6'-(NHC(6)H(5))(2)-2,2'-(1,3,5-C(3)N(3))(2), is reported, and its coordination with Co, Ni and Cu is explored. Reactions of metal salts (2 equiv) with Btzn (1 equiv) result in dimeric species [(Btzn)Co(2)(NCS)(4)(EtOH)(2)(DMF)(2)], (2), [(Btzn)Ni(2)(η(1)-ONO(2))(2)(MeOH)(4)(DMF)...
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Biguanide groups and biguanidinium cations incorporate multiple sites that can donate or accept hydrogen bonds. To assess their ability to associate and to direct the formation of extended hydrogen-bonded networks, we examined the structure of crystals of four compounds in which two neutral biguanide groups or the corresponding cations are attached...
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Monohydrochloride salts of diverse 1-arylbiguanides and 1,5-diarylbiguanides were synthesized by the reaction of anilinium chlorides with dicyandiamide or sodium dicyanamide, and the biguanidinium chlorides were converted into the corresponding biguanides by deprotonation with methanolic NaOCH3. The resulting biguanides and their salts were fully c...
Article
Tetraphenylmethane, tetraphenylsilane, and simple derivatives with substituents that do not engage in hydrogen bonding typically crystallize as close-packed structures with essentially no space available for the inclusion of guests. In contrast, derivatives with hydrogen-bonding groups are known to favor the formation of open networks that include...
Article
Useful derivatives of tetraphenylmethane and tetraphenylsilane have been synthesized by efficient methods that give crystalline products without chromatographic purification. New compounds include tetrakis(4-hydroxyphenyl)methane (21), tetrakis(4-formylphenyl)methane (22), tetrakis[(4-hydroxymethyl)phenyl]methane (23), tetrakis(4-bromophenyl)silane...
Article
Protonolyses of carbon–hydrogen bonds can occur under suitable conditions to produce carbocations and H2. In an effort to accelerate these fundamental reactions, we have attempted to make them intramolecular by devising compounds in which carbon–hydrogen bonds designed to be particularly good formal donors of hydride are held in close proximity to...
Article
Isomeric 2,2'-bipyridines 4a-6a and 1,10-phenanthrolines 7a-9a with two diaminotriazinyl (DAT) substituents were synthesized to explore their dual ability to direct association by the chelation of metals and the characteristic hydrogen bonding of DAT groups. Crystals of compounds 4a-6a and 7a-9a were grown under diverse conditions, and their struct...
Article
Crystals of isomeric pyridyl-substituted diaminotriazines 1a−c and elongated analogues 2a−b were grown under various conditions, and their structures were solved by X-ray crystallography. Analysis of the structures revealed three shared features: (1) The compounds favor flattened conformations; (2) they participate in approximately coplanar hydroge...
Article
Pyridinecarboxylic acids 3-9 are adsorbed from solution onto graphite to produce well-ordered adlayers that can be imaged by scanning tunneling microscopy. Hydrogen bonds involving the carboxyl groups and the nitrogen atom of the pyridyl ring play key roles in controlling the observed two-dimensional (2D) organization. Pyridinecarboxylic acids have...
Article
The cascade of events that regulate cell-substrate interactions is not yet fully understood. However, it is now generally recognized that proteins adsorbed on a substrate prior to its colonization have a major influence on initiating and directing cellular activities. Protein adsorption and the characteristics of the adsorbed layer are determined i...
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DFT calculations reveal that aminotriazines have a strong affinity for graphite and suggest that part of the driving force for adsorption is a specific attractive interaction of NR(2) groups with the underlying surface.
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Similar to crown ethers and other multidentate Lewis bases, multidentate Lewis acids have unique features that promise to give them broad utility in chemistry. In particular, they can be designed so that their multiple sites of Lewis acidity are able to interact simultaneously with basic sites in guest molecules, so leading to recognition, binding...
Article
The principles of crystal engineering can be used in a contrary way to help devise molecules that resist crystallization and form long-lived glasses. This can be achieved by making structural changes that thwart established patterns of crystallization. In using this strategy to block the crystallization of triarylamines, we have found that the intr...
Article
Hexaphenylbenzene (HPB) and analogous compounds have properties of broad utility in science and technology, including conformationally well-defined molecular structures, high thermal stability, high HOMO-LUMO gaps, little self-association, inefficient packing, and high solubilities. Previous structural studies of HPB and its analogues have revealed...
Article
Acetylene sponges can be created by taking advantage of the nonplanar geometry of hexaphenylbenzenes and the special capacity of the central aromatic ring to engage in C(sp)-H...pi interactions reinforced by secondary C(sp(2))-H...pi interactions, as revealed by X-ray crystallographic studies and DFT calculations.
Article
Hexaphenylbenzene and related derivatives of benzene with multiple contiguous phenyl substituents have well-defined nonplanar topologies. Their structures limit conjugation and disfavor intermolecular π−π and C−H···π interactions. Such compounds therefore show higher HOMO−LUMO gaps, lower degrees of self-association, less efficient packing, and hig...
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We have recently shown that molecular glasses, small molecules capable of readily forming glassy solids as opposed to crystals, can be designed by exploiting molecular association through strong and directional intermolecular interactions, as exemplified by several members of the bis(mexylamino)triazine family. Herein, 43 new bis(mexylamino)triazin...