A neutral naphthalene diimide [2]rotaxane

A neutral donor-acceptor [2]rotaxane, which has been synthesized using click chemistry, has had its solid-state structure and superstructure elucidated by X-ray crystallography. Both dynamic H-1 NMR spectroscopy and electrochemical investigations have been employed in an attempt to shed light on both geometrical reorganization and redox-switching processes that are occurring or can be induced within the [2]rotaxane.A neutral donor-acceptor [2]rotaxane, which has been synthesized using click chemistry, has had its solid-state structure and superstructure elucidated by X-ray crystallography. Both dynamic (1)H NMR spectroscopy and electrochemical investigations have been employed in an attempt to shed light on both geometrical reorganization and redox-switching processes that are occurring or can be induced within the [2]rotaxane

A Water-Soluble pH-Triggered Molecular Switch

A bistable donor–acceptor [2]­catenane, which is composed of a crown ether containing a hydroquinone unit and a 1,5-diaminonaphthalene unit, interlocked mechanically by cyclobis­(paraquat-<i>p</i>-phenylene) as its tetrachloride, exists as a mixture of translational isomers, both in the solid state and in aqueous solution. UV/vis and ¹H NMR spectroscopies demonstrate that this isomeric mixture can be switched in water in the presence of hydrochloric acid to afford a single diprotonated derivative in which only the hydroquinone unit resides inside the cavity of the tetracationic cyclophane. Treatment with 1,4-diazabicyclo[2.2.2]­octane resets the molecular switch

A Neutral Naphthalene Diimide [2]Rotaxane

A neutral donor–acceptor [2]rotaxane, which has been synthesized using click chemistry, has had its solid-state structure and superstructure elucidated by X-ray crystallography. Both dynamic ¹H NMR spectroscopy and electrochemical investigations have been employed in an attempt to shed light on both geometrical reorganization and redox-switching processes that are occurring or can be induced within the [2]rotaxane

A Water-Soluble pH-Triggered Molecular Switch

A bistable donor–acceptor [2]­catenane, which is composed of a crown ether containing a hydroquinone unit and a 1,5-diaminonaphthalene unit, interlocked mechanically by cyclobis­(paraquat-<i>p</i>-phenylene) as its tetrachloride, exists as a mixture of translational isomers, both in the solid state and in aqueous solution. UV/vis and ¹H NMR spectroscopies demonstrate that this isomeric mixture can be switched in water in the presence of hydrochloric acid to afford a single diprotonated derivative in which only the hydroquinone unit resides inside the cavity of the tetracationic cyclophane. Treatment with 1,4-diazabicyclo[2.2.2]­octane resets the molecular switch

ExBox: a polycyclic aromatic hydrocarbon scavenger

A template-directed protocol, which capitalizes on donor acceptor interactions, is employed to synthesize a semi-rigid cyclophane (ExBox(4+)) that adopts a box-like geometry and is comprised of pi-electron-poor 1,4-phenylene-bridged ("extended") bipyridinium units (ExBIPY(2+)). ExBox(4+) functions as a high-affinity scavenger of an array of different polycyclic aromatic hydrocarbons (PAHs), ranging from two to seven fused rings, as a result of its large, accommodating cavity (approximately 3.5 angstrom in width and 11.2 angstrom in length when considering the van der Waals radii) and its ability to form strong non-covalent bonding interactions with pi-electron-rich PAHs in either organic or aqueous media. In all, 11 PAH guests were observed to form inclusion complexes with ExBox(4+), with coronene being the largest included guest. Single-crystal X-ray diffraction data for the 11 inclusion complexes EaBox(4+)subset of PAH as well as UV/vis spectroscopic data for 10 of the complexes provide evidence of the promiscuity of ExBox(4+) for the various PAHs. Nuclear magnetic resonance spectroscopy and isothermal titration calorimetric analyses of 10 of the inclusion complexes are employed to further characterize the host guest interactions in solution and determine the degree with which ExBox(4+) binds each PAR compound. As a proof-of-concept, a batch of crude oil from Saudi Arabia was subjected to extraction with the water-soluble form of the PAH receptor, ExBox center dot 4Cl, resulting in the isolation of different aromatic compounds after ExBox center dot 4Cl was regenerated.A template-directed protocol, which capitalizes on donor− acceptor interactions, is employed to synthesize a semi-rigid cyclophane (ExBox4+) that adopts a box-like geometry and is comprised of π-electronpoor 1,4-phenylene-bridged (“extended”) bipyridinium units (ExBIPY2+). ExBox4+ functions as a high-affinity scavenger of an array of different polycyclic aromatic hydrocarbons (PAHs), ranging from two to seven fused rings, as a result of its large, accommodating cavity (approximately 3.5 Å in width and 11.2 Å in length when considering the van der Waals radii) and its ability to form strong non-covalent bonding interactions with π-electron-rich PAHs in either organic or aqueous media. In all, 11 PAH guests were observed to form inclusion complexes with ExBox4+, with coronene being the largest included guest. Single-crystal X-ray diffraction data for the 11 inclusion complexes ExBox4+⊂PAH as well as UV/vis spectroscopic data for 10 of the complexes provide evidence of the promiscuity of ExBox4+ for the various PAHs. Nuclear magnetic resonance spectroscopy and isothermal titration calorimetric analyses of 10 of the inclusion complexes are employed to further characterize the host−guest interactions in solution and determine the degree with which ExBox4+ binds each PAH compound. As a proof of-concept, a batch of crude oil from Saudi Arabia was subjected to extraction with the water-soluble form of the PAH receptor, ExBox·4Cl, resulting in the isolation of different aromatic compounds after ExBox·4Cl was regenerated

Synthesis, Structure, and Metalation of Two New Highly Porous Zirconium Metal–Organic Frameworks

Three new metal–organic frameworks [MOF-525, Zr₆O₄(OH)₄(TCPP-H₂)₃; MOF-535, Zr₆O₄(OH)₄(XF)₃; MOF-545, Zr₆O₈(H₂O)₈(TCPP-H₂)₂, where porphyrin H₄-TCPP-H₂ = (C₄₈H₂₄O₈N₄) and cruciform H₄-XF = (C₄₂O₈H₂₂)] based on two new topologies, <b>ftw</b> and <b>csq</b>, have been synthesized and structurally characterized. MOF-525 and -535 are composed of Zr₆O₄(OH)₄ cuboctahedral units linked by either porphyrin (MOF-525) or cruciform (MOF-535). Another zirconium-containing unit, Zr₆O₈(H₂O)₈, is linked by porphyrin to give the MOF-545 structure. The structure of MOF-525 was obtained by analysis of powder X-ray diffraction data. The structures of MOF-535 and -545 were resolved from synchrotron single-crystal data. MOF-525, -535, and -545 have Brunauer–Emmett–Teller surface areas of 2620, 1120, and 2260 m²/g, respectively. In addition to their large surface areas, both porphyrin-containing MOFs are exceptionally chemically stable, maintaining their structures under aqueous and organic conditions. MOF-525 and -545 were metalated with iron­(III) and copper­(II) to yield the metalated analogues without losing their high surface area and chemical stability

Synthesis, Structure, and Metalation of Two New Highly Porous Zirconium Metal–Organic Frameworks

Three new metal–organic frameworks [MOF-525, Zr₆O₄(OH)₄(TCPP-H₂)₃; MOF-535, Zr₆O₄(OH)₄(XF)₃; MOF-545, Zr₆O₈(H₂O)₈(TCPP-H₂)₂, where porphyrin H₄-TCPP-H₂ = (C₄₈H₂₄O₈N₄) and cruciform H₄-XF = (C₄₂O₈H₂₂)] based on two new topologies, <b>ftw</b> and <b>csq</b>, have been synthesized and structurally characterized. MOF-525 and -535 are composed of Zr₆O₄(OH)₄ cuboctahedral units linked by either porphyrin (MOF-525) or cruciform (MOF-535). Another zirconium-containing unit, Zr₆O₈(H₂O)₈, is linked by porphyrin to give the MOF-545 structure. The structure of MOF-525 was obtained by analysis of powder X-ray diffraction data. The structures of MOF-535 and -545 were resolved from synchrotron single-crystal data. MOF-525, -535, and -545 have Brunauer–Emmett–Teller surface areas of 2620, 1120, and 2260 m²/g, respectively. In addition to their large surface areas, both porphyrin-containing MOFs are exceptionally chemically stable, maintaining their structures under aqueous and organic conditions. MOF-525 and -545 were metalated with iron­(III) and copper­(II) to yield the metalated analogues without losing their high surface area and chemical stability

ExBox: A Polycyclic Aromatic Hydrocarbon Scavenger

A template-directed protocol, which capitalizes on donor–acceptor interactions, is employed to synthesize a semi-rigid cyclophane (<b>ExBox</b>⁴⁺) that adopts a box-like geometry and is comprised of π-electron-poor 1,4-phenylene-bridged (“extended”) bipyridinium units (<b>ExBIPY</b>²⁺). <b>ExBox</b>⁴⁺ functions as a high-affinity scavenger of an array of different polycyclic aromatic hydrocarbons (PAHs), ranging from two to seven fused rings, as a result of its large, accommodating cavity (approximately 3.5 Å in width and 11.2 Å in length when considering the van der Waals radii) and its ability to form strong non-covalent bonding interactions with π-electron-rich PAHs in either organic or aqueous media. In all, 11 PAH guests were observed to form inclusion complexes with <b>ExBox</b>⁴⁺, with coronene being the largest included guest. Single-crystal X-ray diffraction data for the 11 inclusion complexes <b>ExBox</b>⁴⁺⊂PAH as well as UV/vis spectroscopic data for 10 of the complexes provide evidence of the promiscuity of <b>ExBox</b>⁴⁺ for the various PAHs. Nuclear magnetic resonance spectroscopy and isothermal titration calorimetric analyses of 10 of the inclusion complexes are employed to further characterize the host–guest interactions in solution and determine the degree with which <b>ExBox</b>⁴⁺ binds each PAH compound. As a proof-of-concept, a batch of crude oil from Saudi Arabia was subjected to extraction with the water-soluble form of the PAH receptor, <b>ExBox</b>·4Cl, resulting in the isolation of different aromatic compounds after <b>ExBox</b>·4Cl was regenerated

ExBox: A Polycyclic Aromatic Hydrocarbon Scavenger

A template-directed protocol, which capitalizes on donor–acceptor interactions, is employed to synthesize a semi-rigid cyclophane (<b>ExBox</b>⁴⁺) that adopts a box-like geometry and is comprised of π-electron-poor 1,4-phenylene-bridged (“extended”) bipyridinium units (<b>ExBIPY</b>²⁺). <b>ExBox</b>⁴⁺ functions as a high-affinity scavenger of an array of different polycyclic aromatic hydrocarbons (PAHs), ranging from two to seven fused rings, as a result of its large, accommodating cavity (approximately 3.5 Å in width and 11.2 Å in length when considering the van der Waals radii) and its ability to form strong non-covalent bonding interactions with π-electron-rich PAHs in either organic or aqueous media. In all, 11 PAH guests were observed to form inclusion complexes with <b>ExBox</b>⁴⁺, with coronene being the largest included guest. Single-crystal X-ray diffraction data for the 11 inclusion complexes <b>ExBox</b>⁴⁺⊂PAH as well as UV/vis spectroscopic data for 10 of the complexes provide evidence of the promiscuity of <b>ExBox</b>⁴⁺ for the various PAHs. Nuclear magnetic resonance spectroscopy and isothermal titration calorimetric analyses of 10 of the inclusion complexes are employed to further characterize the host–guest interactions in solution and determine the degree with which <b>ExBox</b>⁴⁺ binds each PAH compound. As a proof-of-concept, a batch of crude oil from Saudi Arabia was subjected to extraction with the water-soluble form of the PAH receptor, <b>ExBox</b>·4Cl, resulting in the isolation of different aromatic compounds after <b>ExBox</b>·4Cl was regenerated