Solid-state structures of rosette and crinkled tape motifs derived from the cyanuric acid melamine lattice

Zerkowski, Jonathan A.; Seto, Christopher T.; Whitesides, George M.

doi:10.1021/ja00039a096

Cited by 304 publications

(153 citation statements)

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“…2). 11,[101][102][103][104][105] Ironically the focus of these studies was not so much the physical properties of the resulting co-crystals but rather the supramolecular functionality of barbitals 106 and their complementarity with melamine. Nevertheless, these studies illustrated very well the potential diversity of forms that can exist for a particular API as more than 60 co-crystals were structurally characterized in this series of studies.…”

Section: Case Studies Of Pharmaceutical Co-crystalsmentioning

confidence: 99%

Pharmaceutical Co-Crystals

Vishweshwar

McMahon

Bis

et al. 2006

Journal of Pharmaceutical Sciences

893

634

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Section: Case Studies Of Pharmaceutical Co-crystalsmentioning

confidence: 99%

Pharmaceutical Co-Crystals

Vishweshwar

McMahon

Bis

et al. 2006

Journal of Pharmaceutical Sciences

893

634

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“…It was found that barbiturates or cyanurates could self-assemble into highly organized structures such as linear tapes, crinkle tapes, or rosettes with complementary hydrogen-bonding melamines in the solid state or solution. [10][11][12][13][14][15][16][17][18] More recently, the formation of hydrogenbonding networks between these complementary components has also been investigated in 2-D at the air-water interface. 19,20 Traditionally, it was believed that hydrogen bonding directed molecular recognition is difficult in polar media, such as water, due to the competition from the latter.…”

Section: Introductionmentioning

confidence: 99%

Polarization-Modulated Infrared Reflection Absorption Spectroscopic Studies of a Hydrogen-Bonding Network at the Air−Water Interface

et al. 1999

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The hydrogen-bonding network formed between a triaminotriazine amphiphile (2C 18 TAZ, 1) and complementary barbituric acid (BA, 2) at the air-water interface is investigated by polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). The molecular structure and orientation of the 1:1 hydrogenbonding network at the air-water interface is revealed in this study. Without the addition of BA to the subphase, the NH 2 scissoring of 2C 18 TAZ appeared in the spectrum as a broad negative absorption band between 1660 and 1605 cm -1 , indicating its perpendicular orientation to the air-water interface. When BA was added to the subphase, the NH 2 scissoring absorption band from the triaminotriazine moiety disappeared due to the complementary hydrogen bonding of BA to the 2C 18 TAZ monolayer. The formation of the rigid 1:1 hydrogen-bonding network also resulted in the disappearance of one of the ring quadrant stretch absorption bands of the 2C 18 TAZ molecule. New bands which are attributed to the vibration of BA can be clearly seen. Particularly, the CdO stretch from BA shows up in the spectra as two negative absorption bands around 1700 cm -1 . The negative signature of these two bands suggests that the BA molecules are oriented in the hydrogen-bonding network with the C-2 carbonyl positioned vertically toward the air, and the C-4 and C-6 carbonyls directed into the water subphase. This is consistent with formation of an assembly which optimizes the use of complementary hydrogen bonding between two components. Furthermore, the effect of competitive polar organic solvents in subphase, such as DMSO, on the hydrogen-bonding network has also been observed in this study. Compared to the previous IRRAS studies on the similar monolayers, the sensitivity of PM-IRRAS is obviously improved. PM-IRRAS will likely become a powerful analytical technique for the characterization of molecular structure and orientation of Langmuir monolayers at the air-water interface.

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“…1b). 9,15,16 We have used chiral recognition to assemble porous organic cages 3 (POCs) into structures with 3-D pore channels (Fig. 1c).…”

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confidence: 99%

Reticular synthesis of porous molecular 1D nanotubes and 3D networks

et al. 2016

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Synthetic control over pore size and pore connectivity is the crowning achievement for porous metal-organic frameworks. The same level of control has not been achieved for molecular crystals, which are not defined by strong, directional intermolecular coordination bonds. Hence, molecular crystallization is inherently less controllable than framework crystallization, and there are fewer examples of 'reticular synthesis'-where multiple building blocks can be assembled according to a common assembly motif.Here, we apply a chiral recognition strategy to a new family of tubular covalent cages, to create both 1-D porous nanotubes and 3-D diamondoid pillared porous networks.The diamondoid networks are analogous to metal-organic frameworks prepared from tetrahedral metal nodes and linear, ditopic organic linkers. The crystal structures can be rationalized by computational lattice energy searches, which provide an in silico screening method to evaluate candidate molecular building blocks. These results are a blueprint for applying the 'node and strut' principles of reticular synthesis to molecular crystals.Despite many advances in supramolecular chemistry, it is still challenging to control molecular crystallization to create a specific, useful property. 1,2 This is important in the emerging area of porous molecular solids, 3 which have practical advantages such as solution processability. The crystal packing in porous molecular crystals defines the pore dimensions, which in turn define properties such as guest selectivity. 4,5 The same challenge-control over solid state structure-applies to all 2 functional molecular crystals because crystal packing defines physical properties such as electronic band gap and thermal or electrical conductivity.A central paradigm in crystal engineering is to synthesize building blocks, or 'tectons', with strong, directional interactions, such as hydrogen bonding 6 or metal-ligand binding, 7 which direct assembly into a targeted three-dimensional superstructure (Fig. 1). 1,2,8,9 For metal-organic frameworks (MOFs) and porous coordination polymers (PCPs), directional metal-ligand bonds are used to do this (Fig. 1a). [10][11][12][13][14] Likewise, hydrogen bonding can be used to create organic molecular crystals with defined network structures (Fig. 1b). 9,15,16 We have used chiral recognition to assemble porous organic cages 3 (POCs) into structures with 3-D pore channels (Fig. 1c). 3 POCs are rigid molecules with a permanent internal void that is accessible to guests via 'windows' in the cage. [17][18][19] Control of structure and function for POCs can be difficult, however, because slight changes in the molecular structure 19 or the crystallization solvent 20 can cause a profound change in the crystal packing. Chiral window-towindow interactions (Fig. 1e,f) can direct these POCs to assemble into 3-D pore networks in several cases, 19,21,22 but this is not ubiquitous. For example, some cages require specific solvents to template the window-to-window packing. 20 The chiral cage CC3-S (...

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Solid-state structures of rosette and crinkled tape motifs derived from the cyanuric acid melamine lattice

Cited by 304 publications

References 3 publications

Pharmaceutical Co-Crystals

Pharmaceutical Co-Crystals

Polarization-Modulated Infrared Reflection Absorption Spectroscopic Studies of a Hydrogen-Bonding Network at the Air−Water Interface

Reticular synthesis of porous molecular 1D nanotubes and 3D networks

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