202798-00-3Relevant academic research and scientific papers
Importance of the order of successive catalyst-transfer condensation polymerization in the synthesis of block copolymers of polythiophene and poly(p-phenylene)
Miyakoshi, Ryo,Yokoyama, Akihiro,Yokozawa, Tsutomu
, p. 1022 - 1023 (2008)
Successive catalyst-transfer condensation polymerization of a Grignard-type phenylene monomer and then a thiophene monomer with a Ni catalyst yields well-defined block copolymers of poly(p-phenylene) and polythiophene, but the reverse order of polymerization results in polymers with broad molecular weight distribution. Copyright
Neutral Heteroleptic Lanthanide Complexes for Unravelling Host-Guest Assemblies in Organic Solvents: The Law of Mass Action Revisited
Babel, Lucille,Baudet, Karine,Besnard, Céline,Kale, Vishal,Mirzakhani, Mohsen,Naseri, Soroush,Nozary, Homayoun,Piguet, Claude
supporting information, p. 62 - 75 (2020/02/20)
The binding of lanthanide containers [Ln(β-diketonate)3dig] [dig = 1-methoxy-2-(2-methoxyethoxy)ethane] to aromatic tridentate N-donor ligands (L) in dichloromethane produces neutral nine-coordinate heteroleptic [LLn(β-diketonate)3] complexes, the equilibrium reaction quotients of which vary with the total concentrations of the reacting partners. This problematic drift prevents the determination of both reliable thermodynamic stability constants and intrinsic host-guest affinities. The classical solution theory assigns this behavior to changes in the activity coefficients of the various partners in nonideal solutions, and a phenomenological approach attempts to quantitatively attribute this effect to some partition of the solvent molecules between bulk-innocent and contact-noninnocent contributors to the chemical potential. This assumption eventually predicts an empirical linear dependence of the equilibrium reaction quotient on the concentration of the formed [LLn(β-diketonate)3] complexes, a trend experimentally supported in this contribution for various ligands L differing in lipophilicity and nuclearity and for lanthanide containers grafted with diverse β-diketonate coligands. Even if the origin of the latter linear dependence is still the subject of debate, this work demonstrates that this approach can be exploited by experimentalists for extracting reliable thermodynamic constants suitable for analyzing and comparing host-guest affinities in organic solvents.
Chemical Potential of the Solvent: A Crucial Player for Rationalizing Host–Guest Affinities
Baudet, Karine,Guerra, Sebastiano,Piguet, Claude
supporting information, p. 16787 - 16798 (2017/10/07)
Access to reliable values of the thermodynamic constants βH,G1,1, which control simple host–guest ([HG]) association, is crucial in medicine, biology, pharmacy, and chemistry, since the optimum concentration of an effector (i.e., a drug) acting on a receptor is set to 1/βH,G1,1. Intermolecular association between charged species in polar solvents, for which water is the archetype, largely obeys this principle. Any deviation from ideality, which alters the speciation in solution, is mastered by the Debye–Hückel theory of ionic atmosphere. Much less is known for related association reactions involving neutral species in non-polar (lipophilic) media such as membranes, bilayers, or organic polymers. Taking the intermolecular association between [La(hfa)3dig] guest (hfa=hexafluoroacetylacetonate, dig=2-{2-methoxyethoxy}ethane) and tridentate polyaromatic host receptors L1–L3 in dichloromethane as a proof-of-concept, we show that the progress of the association reactions, as measured by the increase in the mole fraction of occupied sites of the receptors, disrupt the chemical potential of the solvent to such an extent that βH,G1,1 may seemingly be shifted by two orders of magnitude, thus leading to erroneous dose-response prescriptions. A simple chemical model, which considers a subset of solvent molecules in surface contact with the partners of the association reaction, restores reliable access to true and interpretable thermodynamic constants. The concomitant emergence of a concentration-dependent corrective parameter reestablishes satisfying dose-dependent response under real conditions. This “complement” to the law of mass action offers a simple method for safely taking care of the non-predictable variations of the activity coefficients of the various partners when host–guest reactions are conducted in non-polar media.
Versatile bisethynyl[60]fulleropyrrolidine scaffolds for mimicking artificial light-harvesting photoreaction centers
Kremer, Adrian,Bietlot, Emerance,Zanelli, Alberto,Malicka, Joanna M.,Armaroli, Nicola,Bonifazi, Davide
supporting information, p. 1108 - 1117 (2015/03/05)
Fullerene-based tetrads, triads, and dyads are presented in which [60]fulleropyrrolidine synthons are linked to an oligo(p-phenyleneethynylene) antenna at the nitrogen atom and to electron-donor phenothiazine (PTZ) and/or ferrocene (Fc) moieties at the ?±
Linear bimetallic alkynylplatinum(II) terpyridyl complexes bearing p-phenylene ethynylene oligomers: Synthesis, characterization, aggregation, and photophysical properties
Xu, Peng,Wu, Haotian,Jia, Hongxing,Ye, Shifan,Du, Pingwu
, p. 2738 - 2746 (2014/06/24)
The series of luminescent bimetallic alkynylplatinum(II) terpyridyl complexes [(tBu3-tpy)PtC≡C(ArC≡C)nPt(tBu 3-tpy)](PF6)2 (I-IV; tBu3-tpy = 4,4′,4″-tritertbutyl-2,2′:6′,2″-terpyridine, Ar
Self-assembled monolayers of clamped oligo(phenylene-ethynylene- butadiynylene)s
Jester, Stefan-S.,Schmitz, Daniela,Eberhagen, Friederike,Hoeger, Sigurd
supporting information; experimental part, p. 8838 - 8840 (2011/09/14)
Rigid rod oligo(phenylene-ethynylene-butadiynylene)s (oPEBs), "half-rings" of two rigid rods connected via a molecular clamp unit, and shape-persistent macrocycles (cyclic "half-ring dimers") are synthesized and their self-assembled monolayers (SAMs) are
Aryl trihydroxyborate salts: Thermally unstable species with unusual gelation abilities
Moy, Cheryl L.,Kaliappan, Raja,McNeil, Anne J.
experimental part, p. 8501 - 8507 (2011/12/04)
A series of aryl trihydroxyborate salts were synthesized and found to form gels in benzene. The compounds were thermally unstable and readily underwent protodeboronation in solution and the solid state. Gelation could be induced without decomposition via sonication. Subsequent characterization studies revealed an unusual dependence of gel properties on alkyl chain length.
Metal ion detection by luminescent 1,3-bis(dimethylaminomethyl) phenyl receptor-modified chromophores and cruciforms
Mangalum, Anshuman,Gilliard Jr., Robert J.,Hanley, Jessica M.,Parker, Austa Marie,Smith, Rhett C.
supporting information; experimental part, p. 5620 - 5627 (2011/02/18)
Chromophores ranging from simple small molecule π-conjugated systems comprised of phenylene ethynylene or fluorenylethynyl units to cross-conjugated Bunz-type cruciforms have been derivatized to include 1,3- bis(dimethylaminomethyl)phenyl moieties. The photophysical responsiveness of these diamino-substituted chromophores to metal ions has been examined. Both emission enhancement (turn-on) and ratiometric fluorescence detection of Cu 2+ and Zn2+ ions have been achieved in THF.
Mechanistic studies on Ni(dppe)Cl2-catalyzed chain-growth polymerizations: Evidence for rate-determining reductive elimination
Lanni, Erica L.,McNeil, Anne J.
supporting information; experimental part, p. 16573 - 16579 (2010/02/16)
The mechanisms for Ni(dppe)Cl2-catalyzed chain-growth polymerization of 4-bromo-2,5-bis-(hexyloxy)phenylmagnesium chloride and 5-bromo-4-hexylthiophen-2-ylmagnesium chloride were investigated. Rate studies utilizing IR spectroscopy and gas chromatography revealed that both polymerizations exhibit a first-order dependence on the catalyst concentration but a zeroth-order dependence on the monomer concentration. 31P NMR spectroscopic studies of the reactive organometallic intermediates suggest that the resting states are unsymmetrical NiII-biaryl and Ni II-bithiophene complexes. In combination, the data implicate reductive elimination as the rate-determining step for both monomers. Additionally, LiCl was found to have no effect on the rate-determining step or molecular weight distribution in the arene polymerization.
P-phenyleneethynylene molecular wires: Influence of structure on photoinduced electron-transfer properties
Wielopolski, Mateusz,Atienza, Carmen,Clark, Timothy,Guldi, Dirk M.,Martin, Nazario
scheme or table, p. 6379 - 6390 (2009/06/18)
A series of donor-acceptor arrays (exTTF-oPPE-C60) containing π-conjugated oligo(phenyleneethynylene) wires (oPPE) of different length between π-extended tetrathiafulvalene (exTTF) as electron donor and fullerene (C60) as electron acceptor has been prepared by following a convergent synthesis. The key reaction in these approaches is the bromo-iodo selectivity of the Hagihara-Sonogashira reaction and the deprotecting of acetylenes with different silyl groups to afford the corresponding donor-acceptor conjugates in moderate yields. The electronic interactions between the three electroactive species were determined by using UV-visible spectroscopy and cyclic voltammetry. Our studies clearly confirm that, although the C60 units are connected to the exTTF donor through π-conjugated oPPE frameworks, no significant electronic interactions are observed in the ground state. Theoretical calculations predict how a simple exchange from C=C double bonds (i.e., oligo(p-phenylenevinylene) to C≡C triple bonds (i.e., oPPE) in the electron donor-acceptor conjugates considerably alters long-range electron transfer. Photoexcitation of exTTF-oPPE-C 60 leads to the following features: a transient photoproduct with maxima at 660 and 1000 nm, which are unambiguously attributed to the photolytically generated radical-ion-pair state, [exTTF+-oPPE- C60-]. Both charge-separation and charge-recombination processes give rise to a molecular-wire behaviour of the oPPE moiety with an attenuation factor (β) of (0.2 ±0.05) A-1.
