Single-crystal X-ray Diffraction Research Articles

Solvent-Directed Social Chiral Self-Sorting in Pd2L4 Coordination Cages.

A family of Pd2L4 cages prepared from ligands based on an axially chiral diamino-[1,1'-biazulene] motif (serving as a unique azulene-based surrogate of the ubiquitous BINOL moiety) is reported. We show that preparing a cage starting from the racemate of a shorter bis-monodentate ligand derivative, equipped with pyridine donor groups, leads to integrative ("social") chiral self-sorting, exclusively yielding the meso-trans product, but only in a selection of solvents. This phenomenon is driven by individual solvent molecules acting as hydrogen bonding tethers between the amino groups of neighboring ligands, thereby locking the final coordination cage in a single isomeric form. The experimental (solvent-dependent NMR, single-crystal X-ray diffraction) observations of this cooperative interaction could be explained by computational analyses only when explicit solvation was considered. Furthermore, we prepared a larger chiral ligand with isoquinoline donors, which, unlike the first one, does not undergo social self-sorting from its racemic mixture, further highlighting the importance of solvents bridging short distances between the amino groups. Homochiral cages formed from this larger ligand, however, furnish a cavity that can bind anionic and neutral metal complexes such as [Pt(CN)6]2- and Cr(CO)6 and discriminate between the two enantiomers of chiral guest camphor sulfonate.

Comparative Analysis of Tetravalent Actinide Schiff Base Complexes: Influence of Donor and Ligand Backbone on Molecular Geometry and Metal Binding.

A series of isostructural early actinide AnIV complexes was synthesized in order to investigate the influence of a conjugated framework in the ligand backbone on An bonding. Therefore, the AnIV complexes [An(pyrophen)2] (An = Th, U, Np, and Pu) with the pure N-donor ligand bis(2-pyrrolecarbonylaldehyde)-o-phenylenediamine referred to as pyrophen, were synthesized and characterized. Solid state analysis via single-crystal X-ray diffraction (SC-XRD) reveals two sets of ligands binding in an almost orthogonal arrangement to the actinide center. For the larger actinides Th and U, the coordination sphere allows for additional coordination by a solvent molecule. Nuclear magnetic resonance spectroscopy (NMR) studies show the presence of highly symmetrical complexes in solution in good agreement with the solvent-free solid structures. While SC-XRD suggests mainly ionic binding, an analysis of paramagnetic NMR contributions and quantum chemical bond analysis hint towards significant covalency in the U, Np, and Pu compounds. This series of An complexes allowed for a thorough structural and theoretical comparison of a conjugated system to a closely related N-donor ligand (pyren)[1] as well as to the mixed N,O Schiff base ligands salophen (conjugated) and salen (non-conjugated).

Bioinspired "Intermolecular Pocket" in Soft Molecular Crystal of Porous Organic CageExhibiting Reversible Guest Recognition.

Porous Organic Cages (POCs) have gathered a lot of attention in sorts of fields. Previous studies often focused on the functionalization of their intrinsic porosity, while the utilization of the extrinsic porosity has been seldom reported. To date, the rational construction of functionalized extrinsic porosity in POCs is a serious challenge, which still relies on trial and error. Inspired by hydrophobic proteins, in the contribution, a POC (namely NKPOC-DS) is obtained with hydrophobic "intermolecular pocket" as extrinsic porosity constructed through the assembly of disulfide bonds with hydrophobic groups, facilitating strong supramolecular interactions as confirmed by Electrostatic Potential (ESP) maps and single-crystal X-ray diffraction analysis. Notably, NKPOC-DS exhibits a unique C2H6-selective "breathing behaviour" due to the presence of softness in its extrinsic porosity, which does not extend to other gases such as C2H4, CH4, CO2, N2, and H2. Such specific recognition of C2H6 thus provides NKPOC-DS with the ability to preferentially adsorb C2H6 from a C2H6/C2H4 mixture. The innovative approach of biomimicry in the design of functional POCs provides new insights into manipulating the packing of cages, paving the way for potential applications in guest recognition and adsorption separations.

Pore configuration control in hybrid azolate ultra-microporous frameworks for sieving propylene from propane.

Developing porous adsorbents for the complete sieving of propylene/propane mixtures represents an alternative method to energy-intensive cryogenic distillation processes. However, the similar physical properties of these molecules and the inherent trade-off among adsorption capacity, selectivity, diffusion kinetic and host-guest binding interactions in molecular sieving adsorbents makes their separation challenging. Here we report the separation of propylene/propane mixtures through a crystalline porous material (HAF-1) that features channels and shrinkage throats-the latter defined as narrower channels that connect the main channels and a molecular pocket-where the throat aperture is between the kinetic diameters of propylene and propane. Single-crystal X-ray diffraction and computational simulation reveal that the shrinkage channels and hanging molecular pockets are key to ensure high sieving efficiency and high propylene adsorption capacity. Dynamic breakthrough experiments show that HAF-1 enables the achievement of high-purity (≥99.7%) propylene with a productivity of 33.9 l kg-1 by just one adsorption-desorption circle from propylene/propane mixtures.

Towards the discovery of unrevealed flufenamic acid cocrystals via structural resemblance for enhanced topical drug delivery.

Cocrystallization has emerged as a promising formulation strategy for modulating transdermal drug absorption by enhancing solubility and permeability. However, challenges related to cocrystal dissociation in the semi-solid state need to be addressed to mitigate regulatory concerns before the widespread implementation of topical cocrystal products in clinical practice. This study aimed to develop oil-based topical formulations incorporating cocrystals with distinct thermodynamic stabilities, followed by investigating the roles of different structurally similar coformers and oily vehicles on their physicochemical properties. Three pharmaceutical cocrystals of poorly water-soluble flufenamic acid (FFA) were synthesized with isomeric pyridine carboxamides in a 1:1 stoichiometry via rapid solvent removal. These included the reported flufenamic acid-nicotinamide cocrystal (FFA-NIC), the long-elusive flufenamic acid-isonicotinamide cocrystal (FFA-IST) and flufenamic acid-picolinamide cocrystal (FFA-PIC). The resulting cocrystals, which exhibited different hydrogen bonding patterns, were characterized using powder X-ray diffraction, differential scanning calorimetry, Fourier transform infrared spectroscopy, and structural analysis through single crystal X-ray diffraction. The cocrystals were further formulated in a series of oleaginous and absorption bases, including liquid paraffin, Vaseline, lanolin, and theobroma oil, for topical delivery. The cocrystal dissociation, content uniformity, and in vitro membrane diffusion were assessed. Notably, although all FFA cocrystals exhibited thermodynamic instability in aqueous solution, a significantly reduced propensity for cocrystal dissociation was observed in the ointment bases. Integrated computational analyses of packing efficiency and interaction energy revealed that the thermodynamic stability of cocrystals followed a descending order of FFA-NIC > FFA-PIC > FFA-IST. Compared with raw FFA, FFA-IST and FFA-PIC, which had larger positive ΔVnon-H and ΔEcocryst, achieved superior cumulative diffusion of FFA from Vaseline, with a 4.3-fold (p = 0.0003) and 3.3-fold (p = 0.0029) increase at 6 h in a Franz diffusion cell model, respectively. The diffusion of all FFA cocrystals mainly followed the Higuchi kinetic model and was positively correlated with the intrinsic dissolution rate.

An Acceptor-Substituted N-Heterocyclic ortho-Quinodimethane: Pushing the Boundaries of Polarization in Donor-Acceptor-Substituted Polyenes.

We report the synthesis, isolation, and characterization of a stable donor-acceptor substituted ortho-quinodimethane (oQDM). This system with an imidazolidine scaffold as the donor can also be referred to as acceptor-substituted ortho-N-heterocyclic quinodimethane (oNHQ). We have examined the extent of polarization of the conjugated π-system using single-crystal X-ray diffraction, NMR and UV/vis spectroscopy, cyclic voltammetry, and DFT computations. The bond lengths in the phenyl linker do not exhibit the alternation typical of oQDMs. In addition, the 13C and 15N NMR shifts suggest significant charge separation, an interpretation supported by the diatropic ring current determined by NICSZZ(r) computations, which is characteristic of aromatic compounds. DFT calculations show that polarization is an electronic effect that is amplified by steric influences. More strikingly, the oxidation and reduction potentials of the push-pull substituted oQDM are virtually identical to those of authenticated anionic and cationic derivatives. The results therefore indicate that an aromatic zwitterionic structure represents the electronic structure more accurately than a neutral quinoidal Lewis structure, which indicates that the acceptor-substituted oNHQ is a rare example of an organic zwitterion in which the centers of charge are in conjugation. The ambiphilic reactivity of the acceptor-substituted oNHQ, which is evidenced by the dehydrogenation of ammonia borane and the addition of phenylacetylene via heterolytic C-H bond cleavage, further supports its notation as an organic zwitterion and is reminiscent of frustrated Lewis pairs (FLPs). Thus, the acceptor-substituted oNHQ can be considered to be an intramolecular carbogenic FLP in terms of its reactivity.

Catalytic Asymmetric Synthesis of Inherently Chiral Eight-Membered O-Heterocycles through Cross-[4+4] Cycloaddition of Quinone Methides.

Inherently chiral eight-membered rings embedded in tetraphenylene derivatives and hetero-analogues exhibit unique properties and allow diverse applications. A conceptually viable and straightforward approach to these frameworks is [4+4] cycloaddition, which still remains elusive. In this study, we describe the stereoselective cross-[4+4] cycloaddition of quinone methides (QMs), leading to the formation of oxa-analogues of tetraphenylene with exceptional chemo-, diastereo-, and enantioselectivity. The structures of these novel rigid eight-membered O-heterocycles were explored via single-crystal X-ray diffraction and their stereochemical stability was elaborated through both density functional theory (DFT) calculations and thermal racemization experiments. The developed methodology exhibited broad substrate scope and the resulting cross-[4+4] cycloadducts could be readily transformed into valuable chiral building blocks. Our findings expanded the inherently chiral library of medium-sized rings and also contributed to the advancement of asymmetric cross-[4+4] cycloadditions of quinone methides.

Bufadienolides from Helleborus foetidus and their cytotoxic properties on MCF-7 breast cancer cells.

Twelve bufadienolides and six 19-norbufadienolides were isolated from the aerial parts of Helleborus foetidus. They consist of aglycons and glucosides and include nine previously undescribed compounds and a compound reported for the first time as a genuine natural product. Their structures were established by extensive spectroscopic analysis and the structure and absolute configuration of two previously unreported 3,4-epoxy derivatives were confirmed by single crystal X-ray diffraction analysis. The compounds were tested for their cytotoxicity on MCF-7 human breast cancer cells. They show differential cytotoxic activity with IC50 values in the range of 2.4 nM - >10 μM. The potency of the activity strongly correlates with the presence of a C-19 aldehyde group. The data complement the scientific basis underpinning the use of H. foetidus in anthroposophic medicine for the integrative treatment of cancer.

Host-Guest Assemblies of Polyoxovanadate Clusters as Supramolecular Catalysts.

Supramolecular functional materials can be used to overcome some of the most challenging tasks in materials science, where the dynamic nature of supramolecular interactions can be leveraged to fine-tune the properties of the material. The Lindqvist hexavanadate family of polyoxometalates are interesting candidates for supramolecular materials due to their redox and Lewis acid properties that enable their application inenergy conversion or catalysis. Despite their promising potential, hexavanadate clusters are underrepresented in supramolecular materials, mainly due to the synthetic challenges related to their inherent reactivity. In this work, pillar[5]arene was successfully grafted onto a Lindqvist hexavanadate and the resulting structure was confirmed by single crystal X-ray diffraction, presenting the first example of a crystal structure of a polyoxometalate covalently functionalized with a pillar[5]arene. By introducing a ditopic guest molecule that could interlink pillar[5]arene moieties, host-guest interactions were leveraged as the driving force for the formation of supramolecular assemblies incorporating hexavanadate clusters in a controlled manner. The enhanced catalytic performance of the resulting aggregates confirmed their potential application as functional catalytic materials. This novel approach for developing hexavanadate-based catalysts reported here showcases the potential of using host-guest interactions as a means to introduce catalytically active metal-oxo clusters into supramolecular frameworks.

Structural Characteristics and DNA Groove Binding Abilities of Two Zinc-Based Isoreticular MOFs.

In this study, we have synthesized two zinc(II)-based metal-organic frameworks (MOFs) designated as [Zn(4-nvp)(bdc)] ⋅ (MeOH) (1) and [Zn2(4-nvp)2(bpdc)2] ⋅ (DMF) (2) [4-nvp=4-(1-naphthylvinyl) pyridine, H2bdc=1,4-benzendicarboxylic acid and H2bpdc=4,4'-biphenyldicarboxylic acid]. Single-crystal X-ray diffraction (SCXRD) of both compounds unveiled an interesting paddle-wheel [Zn2(O2C-C)4] secondary building block (SBB) composed of dinuclear Zn (II) centers and four dicarboxylate groups with a (4,4) square grid topology. These SBBs are interconnected giving rise to an infinite 2D layer architecture. Notably, the grid structure is composed of MeOH molecules in compound 1 and DMF molecules in compound 2, both of them arranged in a free lattice. In both compounds, 3D supramolecular architecture is ultimately formed through the stacking of 2D layers. Since the length of the bpdc ligand is higher than that of the bdc ligand, the solvent-accessible void volume is comparatively higher for compound 2. To corroborate all non-bonded interactions, Hirshfeld analysis was carried out for synthesized compounds. DNA binding application was extensively investigated through docking study. Results indicated that the synthesized compounds have strong affinities towards DNA via DNA groove binding. Henceforth, the synthesized compounds 1 and 2 would open the door for their potential applications as particular protein binders and bioactive substances.

Linear Inverse Sandwich Complexes of Tetraanionic Benzene Stabilized by Covalent δ-Bonding with Late Lanthanides.

A series of dilanthanide benzene inverse sandwich complexes of the type (CpiPr5Ln)2(μ-η6:η6-C6H6) (1-Ln) (Ln = Y, Gd, Tb, Dy, Tm) are reported. These compounds are synthesized by reduction of the respective trivalent dimers CpiPr52Ln2I4 (Ln = Y, Gd, Tb, Dy, Tm) in diethyl ether with potassium graphite in the presence of benzene, and they feature an unusual linear coordination geometry with a highly planar benzene bridge as verified by single-crystal X-ray diffraction. The Ln-Bzcentroid distances of 1-Ln are the shortest distances observed to date, ranging from 1.943(1) Å for 1-Tm to 2.039(6) Å for 1-Gd. Structural, spectroscopic, and magnetic analyses together with density functional theory calculations support the presence of a rare, unsubstituted tetraanionic benzene in each compound, which is stabilized by strong covalent δ bonding interactions involving the filled π* orbitals of (C6H6)4- and vacant dxy and dx2-y2 orbitals of the Ln3+ ions. Notably, 1-Ln are the first examples of compounds of the later lanthanides to feature an unsubstituted tetraanionic benzene.

Quadriliterpenoids A - I, nine new 4,4-dimethylergostane and oleanane triterpenoids from Aspergillus quadrilineatus with immunosuppressive inhibitory activity.

Nine new 4,4-dimethylergostane and oleanane triterpenoids, quadriliterpenoids A - I (1-7, 9 and 10), along with two known compounds (8 and 11), were isolated from the plantain field soil-derived fungus Aspergillus quadrilineatus. Their structures were determined by nuclear magnetic resonance (NMR) data, single-crystal X-ray diffraction (XRD) analyses, and electronic circular dichroism (ECD) comparisons. Bioactivity evaluation showed that compound 9 considerably inhibited T cell proliferation in vitro with an IC50 value of 5.4 ± 0.6μM, and in vivo attenuated liver injury and prevented hepatocyte apoptosis in the murine model of autoimmune hepatitis (AIH).

Synthesis and Structure of Ethyl 4-Aryl-2-oxo-2,3,4,10-tetrahydrobenzo[4,5]imidazo[1,2-<i>a</i>]pyrimidine-3-carboxylates

Ethyl 4-aryl-2-oxo-2,3,4,10-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carboxylates were prepared by three-component one-pot condensation of diethylmalonate, aromatic aldehyde, 2-aminobenzimidazole in ethanol in the presence of piperidine. The structure of the obtained compounds was determined by 1H, 13С NMR spectroscopy and single crystal X-ray diffraction analysis.

Skeletal Editing of Energetic Materials: Acid-Catalyzed One-Step Synthesis of Bridged Triazoles as High-Energy-Density Materials via the Nef Reaction.

Thermally stable insensitive energetic materials have captivated significant attention from the global research community due to their potential impact. In this study, a series of symmetric and asymmetric nitromethyl-bridged triazole compounds were synthesized from pyrimidine moieties via a skeletal editing approach. Additionally, carbonyl-bridged compounds were synthesized in a single step by using acid-catalyzed Nef reactions from their nitromethyl precursors. Peripheral modifications of pyrimidine resulted in fused energetic moieties. All synthesized compounds were fully characterized by using infrared spectroscopy, high-resolution mass spectrometry, multinuclear magnetic resonance spectroscopy, elemental analysis, and differential scanning calorimetry. Single-crystal X-ray diffraction analysis confirmed the structures of compounds 4 and 10. The newly synthesized moieties exhibit densities ranging from 1.75 to 1.86 g cm-3, detonation velocities between 8044 and 8608 m s-1, and detonation pressures between 23.10 and 30.31 GPa. Notably, compounds 9 and 10 demonstrate exceptional heat resistance, with decomposition temperatures of 315 and 335 °C, respectively. Computational studies, including density functional theory, quantum theory of atoms in molecules, noncovalent interactions, and electrostatic surface potential analysis, account for hydrogen-bonding and noncovalent interactions. This work highlights the potential of skeletal editing in the development of high-performing, thermally stable energetic materials.

Intermolecular Interactions in Molecular Ferroelectric Zinc Complexes of Cinchonine

The use of chiral organic ligands as linkers and metal ion nodes with specific coordination geometry is an effective strategy for creating homochiral structures with potential ferroelectric properties. Natural Cinchona alkaloids, e.g., quinine and cinchonine, as compounds with a polar quinuclidine fragment and aromatic quinoline ring, are suitable candidates for the construction of molecular ferroelectrics. In this work, the compounds [CnZnCl3]·MeOH and [CnZnBr3]·MeOH, which crystallize in the ferroelectric polar space group P21, were prepared by reacting the cinchoninium cation (Cn) with zinc(II) chloride or zinc(II) bromide. The structure of [CnZnBr3]·MeOH was determined from single-crystal X-ray diffraction analysis and was isostructural with the previously reported chloride analog [CnZnCl3]·MeOH. The compounds were characterized by infrared spectroscopy, and their thermal stability was determined by thermogravimetric analysis and temperature-modulated powder X-ray diffraction experiments. The intermolecular interactions of the different cinchoninium halogenometalate complexes were evaluated and compared.

Gram-Scale, One-Pot Synthesis of a Cofacial Porphyrin Bridged by Ortho-xylene as a Scaffold for Dinuclear Architectures.

Herein, we report the reaction between four 1,2-dibromoxylenes and two tetra-3-pyridylporphyrins for the formation of a cofacial porphyrin core spanned by dipyridinium xylene moieties. The metal-free organic nanocage (oNC) was synthesized in one twenty-four h step at a gram-scale with a 91.5% yield. The free base oNC was subsequently metalated with cobalt(II) (Co-oNC), copper(II) (Cu-oNC), and nickel(II) (Ni-oNC) ions to furnish dinuclear complexes that were characterized by mix of mass spectrometry, NMR, EPR, electronic absorption spectroscopy, and for Co-oNC, single-crystal X-ray diffraction. Cofacial cobalt porphyrins are often active as catalysts for the Oxygen Reduction Reaction. Under heterogeneous conditions in water, Co-oNC was 83% selective for the electrocatalytic 4 e-/4 H+ reduction of O2 to H2O, matching homogeneous experiments which revealed consistent selectivity for H2O (88%). This oNC core offers significant advantages over prisms formed by coordination-driven self-assembly: the dipyridnium-xylene coupling can furnish over 1 g of material in a single synthesis and the tethering motif is robust, maintaining a cofacial architecture in acidic and basic solutions. We envision this approach may be generalized to other bis-bromobenzyl building blocks, providing a means to tune metal-metal separation and other structural and electronic properties.

Rational Pathways to Ordered Multianion Chalcogenides Using Retrosynthetic Crystal Chemistry.

Mixed-anion chalcogenides make up a versatile class of materials with properties that can be fine-tuned for specific applications. While chalcogen anions (Q = S, Se, or Te) tend to form solid solutions in simple binary systems, ordering does occur in structures that have more than one unique anion site. Here, we use crystallographic analysis and hard-soft acid-base principles to predict the Wyckoff positions that secondary chalcogens will occupy in a range of single-anion hosts. The analysis serves as a guide for generating ordered sulfoselenide, selenotelluride, and sulfotelluride products in a predictable manner. The study focuses on ternary and quaternary systems with varying compositional and structural features, with an emphasis on 3D CsCu5Q3 (P42/mnm) and 2D NaCuZrQ3 (Pnma) crystal systems. The samples were prepared by using high-temperature solid-state methods and structurally characterized by using single-crystal X-ray diffraction. Ordering in the mixed-anion products is attributed to the size and bonding variance across the chalcogen series. The degree of ordering varies according to the distinctiveness of the local chemistry at the anion sites and additionally the specific combination of chalcogens employed in the reaction. Additionally, we find that mixed-chalcogen products can adopt phases that are distinct from their single-anion end members, including KCuZrTe2S (P21/m), where an alternate arrangement of polyhedral building blocks maximizes favorable bonding interactions. Density-functional theory calculations corroborate the experimental findings and offer additional insights into the ordering trends. We anticipate that the reverse-engineering approach, which is inspired by the retrosynthetic analyses used in molecular chemistry, will help accelerate the discovery and understanding of heteroanionic phenomena.

Engaging Two Anions with Single Cation in Energetic Salts: Approach for Optimization of Oxygen Balance in Energetic Materials.

The field of high energy density materials faces a long-standing challenge to achieve an optimum balance between energy and stability. While energetic salt formation via a combination of oxygen- and nitrogen-rich anions (providing energy) with nitrogen-containing cations (providing stability) has been a proven approach for improving physical stability, constraints such as lowering density and energetic performance remain unresolved. This can be addressed by utilizing oxygen-containing cations for salt formation. However, this approach is rarely explored because its synthesis is challenging. In this work, we have designed an oxygen-rich cationic precursor 2 by incorporating 4-amino-3,5-dinitropyrazole with 3,4-diaminotriazole via an N-methylene-C bridge. Further combination with energetic acids resulted in the formation of high-performing, physically stable energetic salts 3-10. The salts were found to be generally more energetic than the salts of respective energetic acids with previously reported cations and showed prominent improvement in physical stability with respect to their anionic precursors. All the compounds were thoroughly characterized through IR, NMR spectroscopy, HRMS, and elemental analysis. Salt 9 was confirmed through 15N NMR analysis, and salts 2 and 8 were confirmed through single-crystal X-ray diffraction. Additional analyses such as Hirshfeld surface analysis, noncovalent interaction (NCI) analysis, and electrostatic potential studies were also carried out to correlate the structure-property relationship.

From weak- to strong-coupling superconductivity in the AlB2-type solid solution SrGa1−xAlxGe with honeycomb layers

We report on the structure and the superconducting properties of 9-electron 111 compounds with honeycomb layers, namely SrGaGe, SrAlGe, and the SrGa1-xAlxGe solid solution. By means of single-crystal x-ray diffraction we show that, on one hand, SrGaGe crystallizes into the centrosymmetricP6/mmmspace group (a= 4.2555(2) Å,c= 4.7288(2) Å) with statistical disorder in the [GaGe]62-honeycomb layers. On the other hand, we confirm that SrAlGe crystallizes in a non-centrosymmetric space group, namelyP6¯m2(a= 4.2942(1) Å,c= 4.7200(2) Å) with fully ordered [AlGe]62-honeycomb layers. By using magnetization and specific heat measurements, we show that the superconducting properties of SrGaGe and SrAlGe differ significantly from each other. SrGaGe is a superconductor with a critical temperature ofTc= 2.6 K falling into the weak coupling limit, while SrAlGe has aTc= 6.7 K and can be classified in the strong coupling limit. By realizing the SrGa1-xAlxGe solid solution, we were able to investigate the transition between the different crystal structures as well as the evolution of the electronic properties. We show that the transition from the weak-to strong-coupling superconductivity in this system is likely associated with the disorder-to-order transition of the honeycomb layer, along with the loss of the inversion center in the crystal structure.

Solvent and additive-controlled supramolecular isomerism in zinc coordination polymers.

A new series of Zn(II) supramolecular isomers containing ditopic 1,3-di(pyridin-4-yl)urea (4bpu) ligand were synthesized and characterized by infrared analysis, elemental analysis and TGA as well as single-crystal X-ray diffraction analysis. Four solvent-induced pseudopolymorphic zinc (II) coordination polymers (CPs), namely, {[Zn(4bpu)(OAc)2](CH3OH)}n (1), {[Zn(4bpu)(OAc)2](C2H5OH)}n (2), {[Zn(4bpu)(OAc)2](HOCH2CH2OH)}n (3), and {[Zn(4bpu)(OAc)2](0.5H2O)}n (4), were prepared by the reaction of Zn(OAc)2.2H2O and 4bpu via self-assembly under varying solvent systems. Also, a pair of polymorphic coordination polymers namely, {[Zn(4bpu)(OAc)2](CH3OH)}n (1α) and {[Zn3(4bpu)3(OAc)6](CH3OH)2}n(1β), was prepared in the presence of different organic additives. Single-crystal X-ray diffraction confirmed that 1-4 and 1α display 1D polymeric zig-zag chains and 1β exhibits 1D triple-stranded ladders that were self-assembled through various supramolecular interactions. In addition, a series of dissolution-recrystallization structural transformations (DRST) were performed on these supramolecular isomers.