A trinuclear silver coordination polymer from a bipyridine bis-urea macrocyclic ligand and silver triflate

Dawn, Sandipan; Salpage, Sahan R.; Smith, Mark D.; Sharma, Shiv K.; Shimizu, Linda S.

doi:10.1016/j.inoche.2011.09.045

Cited by 22 publications

(7 citation statements)

References 47 publications

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“…The compound is luminescent (l ex = 355 nm, l em = 410, 460, and 485 nm). [81] Similar contacts have also been discussed for the dimers formed with other flat macrocycles, but there also the role of the anions is a point of concern. [60] A Raman study of a supported argentophilic interaction has been carried out for the cyclic dications, shown in formula 19, formed with 1,3-ditertiary phosphine ligands.…”

Section: Vibrational Spectroscopy Criteriamentioning

confidence: 74%

Argentophilic Interactions

2014

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The decade 1990-2000 saw a growing interest in aurophilic interactions in gold chemistry. These interactions were found to influence significantly a variety of structural and other physical characteristics of gold(I) compounds. The attention paid to this unusual and counterintuitive type of intra- and intermolecular bonding between seemingly closed-shell metal centers has rapidly been extended to also include silver chemistry. Hundreds of experimental and computational studies have since been dedicated to the argentophilicity phenomenon. The results of this development are reviewed herein focusing on molecular systems where two or more silver(I) centers are in close contact leading to specific structural characteristics and a variety of novel physical properties. These include strongly modified ligand-to-metal charge-transfer processes observed in absorption and emission spectroscopy, but also colossal positive and negative thermal expansion on the one hand and unprecedented negative linear compressibility of crystal parameters on the other.

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Section: Vibrational Spectroscopy Criteriamentioning

confidence: 74%

Argentophilic Interactions

2014

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“…A weak but significant Ag···Ag interaction is evidenced by a Ag···Ag separation of 3.24 Å, and this interaction was further confirmed by the presence of a low-energy absorption band (50–120 cm –1 ) in the Raman spectrum (Figure S27). , Each silver atom coordinates to three S atoms from three different ligands, and the silver atom is located in the center of the plane formed by the three S atoms. Each S atom is located at one edge of the tetrahedron and bridges two silver atoms.…”

Section: Resultsmentioning

confidence: 99%

Silver Clusters as Robust Nodes and π–Activation Sites for the Construction of Heterogeneous Catalysts for the Cycloaddition of Propargylamines

Chang

Jing

et al. 2018

ACS Catal.

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The use and transformation of carbon dioxide as a C1 source into valuable chemical products using cheap industrial chemicals under mild reaction conditions fulfill the requirements of atom economy in the chemical industry. In this paper, two new silver-cluster-based frameworks were synthesized by incorporating thiourea on the backbone of the tripodal ligands. Given their large pores, high density of catalytic sites, and appropriate coordination geometries, these heterogeneous materials could be used as high-efficiency π-activation catalysts in the atom-economical cycloaddition of propargylamines with carbon dioxide. The loading of 0.1 mol % catalysts enabled the almost complete transformation of the propargylamines into oxazolidinones at atmospheric pressure and room temperature. DFT calculations show significant charge accumulation regions with π* symmetry on C atoms associated with the acetylene bond along the Ag−C directions and charge depletion regions with σ symmetry along the C−C direction, further supporting the important role of silver-cluster-based catalysts in π* activation of substrates for subsequent reactions with approaching CO 2 . The crystallinity of the frameworks allowed the structure of the encapsulated substrates and the interactions of the CC bonds in the active intermediates to be clearly observed. The recyclability and high turnover number of the cycloaddition reaction demonstrate the broad potential applications of these designed materials as πactivation catalysts for practical applications in the chemical industry.

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“…Each bipyridine group is rotated outward to bind with two Ag + ions. We are investigating complexes of 9 with silver due to Ag(I)’s catalytic properties, as well as complexes with Ru(II), Ir(II), and Pt(II) as such complexes may have applications in catalysis and for sensor materials …”

Section: Designmentioning

confidence: 99%

Functional Materials from Self-Assembled Bis-urea Macrocycles

2014

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CONSPECTUS: This Account highlights the work from our laboratories on bis-urea macrocycles constructed from two C-shaped spacers and two urea groups. These simple molecular units assembled with high fidelity into columnar structures guided by the three-centered urea hydrogen bonding motif and aryl stacking interactions. Individual columns are aligned and closely packed together to afford functional and homogeneous microporous crystals. This approach allows for precise and rational control over the dimensions of the columnar structure simply by changing the small molecular unit. When the macrocyclic unit lacks a cavity, columnar assembly gives strong pillars. Strong pillars with external functional groups such as basic lone pairs can expand like clays to accept guests between the pillars. Macrocycles that contain sizable interior cavities assemble into porous molecular crystals with aligned, well-defined columnar pores that are accessible to gases and guests. Herein, we examine the optimal design of the macrocyclic unit that leads to columnar assembly in high fidelity and probe the feasibility of incorporating a second functional group within the macrocycles. The porous molecular crystals prepared through the self-assembly of bis-urea macrocycles display surface areas similar to zeolites but lower than MOFs. Their simple one-dimensional channels are well-suited for studying binding, investigating transport, diffusion and exchange, and monitoring the effects of encapsulation on reaction mechanism and product distribution. Guests that complement the size, shape, and polarity of the channels can be absorbed into these porous crystals with repeatable stoichiometry to form solid host-guest complexes. Heating or extraction with an organic solvent enables desorption or removal of the guest and subsequent recovery of the solid host. Further, these porous crystals can be used as containers for the selective [2 + 2] cycloadditions of small enones such as 2-cyclohexenone or 3-methyl-cyclopentenone, while larger hosts bind and facilitate the photodimerization of coumarin. When the host framework incorporates benzophenone, a triplet sensitizer, UV-irradiation in the presence of oxygen efficiently generates singlet oxygen. Complexes of this host were employed to influence the selectivity of photooxidations of 2-methyl-2-butene and cumene with singlet oxygen. Small systematic changes in the channel and bound reactants should enable systematic evaluation of the effects of channel dimensions, guest dimensions, and channel-guest interactions on the processes of absorption, diffusion, and reaction of guests within these nanochannels. Such studies could help in the development of new materials for separations, gas storage, and catalysis.

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A trinuclear silver coordination polymer from a bipyridine bis-urea macrocyclic ligand and silver triflate

Cited by 22 publications

References 47 publications

Argentophilic Interactions

Argentophilic Interactions

Silver Clusters as Robust Nodes and π–Activation Sites for the Construction of Heterogeneous Catalysts for the Cycloaddition of Propargylamines

Functional Materials from Self-Assembled Bis-urea Macrocycles

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