Dimeric Molecules Research Articles

Effect of weak intermolecular interactions on the ionization of benzene derivatives dimers.

The interactions between π-systems in dimers of aromatic molecules lead to particularly stable conformations within the relative orientations of the monomers. Extensive research has been conducted on the properties of these complexes in the neutral state. However, in recent decades, there has been a significant surge in applications harnessing these structures for electrical purposes. Therefore, this study places particular emphasis on a deeper understanding of the redox properties of these compounds and how to modify them. To achieve this, we have focused on modeling the effect of a wide range of functional groups on the redox properties of benzene derivatives, observing a correlation between these properties and the change in the molecular dipole moment. Then, we investigated the effect of π-stacking interactions on these properties in dimers formed by either identical or different monomers. In both cases, there is an enhancement of the reducing character of the systems due to these interactions. Upon oxidation, the charge is distributed proportionally to the redox potential of each monomer. Therefore, if there is heterogeneity in these potentials, the properties of the complete cationic system will be influenced by the monomer with a greater tendency to undergo oxidation. The considered models serve as an excellent example for studying the behavior of nucleobases in DNA or aromatic amino acids, among others.

Design principles, growth laws, and competition of minimal autocatalysts

The difficulty of designing simple autocatalysts that grow exponentially in the absence of enzymes, external drives or ingenious internal mechanisms severely constrains scenarios for the emergence of evolution by natural selection in chemical and physical systems. Here, we systematically analyze these difficulties in the simplest and most generic autocatalyst: a dimeric molecule that duplicates by templated ligation. We show that despite its simplicity, such an autocatalyst can achieve exponential growth autonomously. We also show, however, that it is possible to design as simple sub-exponential autocatalysts that have an advantage over exponential autocatalysts when competing for a common resource. We reach these conclusions by developing a theoretical framework based on kinetic barrier diagrams. Besides challenging commonly accepted assumptions in the field of the origin of life, our results provide a blueprint for the experimental realization of elementary autocatalysts exhibiting a form of natural selection, whether on a molecular or colloidal scale.

Two pressure-induced molecular superconductors with different types of crystal and electronic structures derived from an unsymmetrical tetrachalcogenafulvalene

Abstract We newly synthesized an organic donor molecule ETTM-STF (ethylenedithio(trimethylene)diselenadithiafulvalene), a molecular hybrid of HMTTF (hexamethylenetetrathiafulvalene) and BETS (bis(ethylenedithio)tetraselenafulvalene). Electrochemical oxidation of ETTM-STF provided two cation radical salts, (ETTM-STF)2Au(CN)2 and (ETTM-STF)2BF4. Crystal structure of the Au(CN)2 salt is characterized by a monolayer structure based on dimerized donor molecules. On the other hand, the BF4 salt shows a bilayer structure that is composed of two crystallographically independent conducting layers with different types of electronic structures. At ambient pressure, the Au(CN)2 salt is a Mott insulator and the BF4 salt undergoes a metal–nonmetal transition where the two types of conducting layers exhibit different behavior. Application of pressure suppressed the nonconducting behavior and induced a superconducting state in the Au(CN)2 salt (Tc = 3.4 K at 9.5 kbar) and in the BF4 salt (Tc = 6.8 K at 8 kbar).

Synthesis and band gap determination for 4-phenyl-7-(5-(thiazol-2-yl) thien-2-yl)benzo[c][1,2,5]thiadiazole, a new polyheterocyclic molecule with potential applications as a semiconductor in organic photovoltaic solar cells

Organic photovoltaic (OPV) solar cells are a promising emerging technology for sustainable energy generation. In these cells, the absorbing layer consists of a repeated series of aromatic organic rings with a system of π delocalized electrons, a feature that allows these materials to absorb sunlight and facilitate electron transfer. In the present work, a new tetrameric molecule with high structural complexity, 4-phenyl-7-(5-(thiazol-2-yl) thien-2-yl)benzo[c][1,2,5]thiadiazole, was synthesized by a convergent pathway. The final step of the synthetic route was the Suzuki coupling of two new dimeric molecules, obtained from commercially available raw materials such as thiophene and o-phenylenediamine. The band gap of the final compound was found to be 2.5 eV using an optical methodology and 2.38 eV using an electrochemical methodology. The results suggest that this tetrameric molecule has potential for application in OPV cells.

Abstract A085: Engineered novel bioactive Nectin-4 dimer protein significantly enhances the binding of TIGIT

Abstract The goals of this study are to: (a) create a novel soluble bioactive Nectin-4 dimer molecule mimicking its native dimer quaternary structure on the cell surface and (b) evaluate the recombinant Nectin-4 dimer binding potency to its receptor vs the monomer form, so that the dimer can be used as an immunogen and an antigen to increase the potential of cancer therapeutic antibody and vaccine discovery when targeting quaternary structural epitopes. Nectin-4 is a cell adhesion molecule belonging to the nectin family. It's involved in cell-cell junctions and plays a role in cancer progression by influencing cell adhesion, migration, and proliferation. Nectin-4 is overexpressed on various types of tumor cells including breast, lung, ovarian and pancreatic cancers. Nectin-4 has been recently identified as a novel ligand of T cell immunoglobulin and ITIM domain (TIGIT) and interaction between Nectin-4 and TIGIT inhibits NK cell cytotoxicity thus suppressing immune responses, allowing cancer cells to evade immune surveillance. Nectin-4 and Nectin-1 interact in a heterophilic manner, however in the context of cancer, altered expression of Nectin-4 and Nectin-1 can contribute to tumor progression. Nectin-4 is a type 1 single transmembrane protein, and can form homodimers on the cell surface. While therapeutics such as Enfortumab Vedotin, an antibody-drug conjugate, binds Nectin-4 on the surface of cancer cells, mimicking the Nectin-4 dimer quaternary structure can present many more critical opportunities for therapeutic antibody and vaccine discovery. To better mimic the native dimer conformation and quaternary structure, we designed a novel soluble Nectin-4 dimer with 3 extracellular domains fused to a dimer motif at the C-terminus. The Nectin-4 dimer protein was expressed and purified from HEK293 cells and confirmed by SDS-PAGE and Western blot analyses. We characterized the Nectin-4 dimer protein binding potency to TIGIT and Nectin-1 by ELISA. Very interestingly, the results demonstrated that the Nectin-4 dimer binding potency to TIGIT increased dramatically as measured by ELISA, compared to the Nectin-4 monomer protein. Conversely, the Nectin-4 dimer binding to Nectin-1 monomer was significantly decreased, compared to Nectin-4 monomer, as expected. We also studied Nectin-4 dimer immunogenicity using a Nectin-4 dimer DNA immunization to induce potent antibody responses in mice. In summary, these findings imply that the Nectin-4 dimer protein is bioactive and in the desirable conformation, resulting in an increased binding potency to its receptor TIGIT, reduced binding to Nectin-1 (as expected), and eliciting strong antibody responses in mice. This novel Nectin-4 dimer protein can be a very useful molecule for cancer research, therapeutic antibody and vaccine discovery. The Nectin-4 dimer protein can be used to: (i) elicit antibody responses against the dimer quaternary structure, (ii) screen antibodies targeting more conformational epitopes, and (iii) study the Nectin-4 and TIGIT ligand/receptor interactions. Citation Format: Christofer Walsh, Timothy Smith, Mikhail Rashkovskii, Richard Parent, Jean Qiu, Shixia Wang. Engineered novel bioactive Nectin-4 dimer protein significantly enhances the binding of TIGIT [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A085.

Dimeric Small Molecule Acceptors via Terminal-End Connections: Effect of Flexible Linker Length on Photovoltaic Performance.

The dimerization of small molecule acceptors (SMAs) holds significant potential by combining the advantages of both SMAs and polymer acceptors in realizing high power conversion efficiency (PCE) and operational stability in organic solar cells (OSCs). However, advancements in the selection and innovation of dimeric linkers are still challenging in enhancing their performance. In this study, three new dimeric acceptors, namely DY-Ar-4, DY-Ar-5, and DY-Ar-6 are synthesized, by linking two Y-series SMA subunits via an "end-to-end" strategy using flexible spacers (octyl, decyl, and dodecyl, respectively). The influence of spacer lengths on device performance is systematically investigated. The results indicate that DY-Ar-5 exhibits more compact and ordered packing, leading to an optimal morphology. OSCs based on PM6: DY-Ar-5 achieves a maximum PCE of 15.76%, attributes to enhance and balance carrier mobility, and reduce carrier recombination. This dimerization strategy using suitable non-conjugated linking units provides a rational principle for designing high-performance non-fullerene acceptors.

Synthesis, characterization, crystal structures and catalytic activity of hydrogen bond mediated 2D and 3D-copper(II) coordination networks based on 2-aminoterepthalic acid and 5-aminoisopthalic acid

Two new copper(II) compounds [Cu2(2-NH2BDC)2(bipy)2(H2O)4] (1) and [Cu2(µ2OH)2(5-aip)(bipy)2(H2O)].5H2O (2) have been synthesized and characterized by elemental analyses, IR, thermogravimetric analysis, and electronic absorption spectroscopy. Molecular structures of compounds 1 and 2 were determined crystallographically. Single crystal X-ray studies show that the coordination network 1 is a centrosymmetrical dimeric unit with the 2-aminoterephthalate ligand bridging the two copper atoms. Each CuII atom is hexacoordinated, residing in an octahedral environment, surrounded by one oxygen and one nitrogen atoms from 2-aminoterephthalate ligand and two nitrogen atoms from one bipy ligand and two water molecules to give a CuO3N3 segmentand generate the an infinite three-dimensional (3D) supramolecular structure resulting from CH•••O interactions between adjacent dimer molecules running parallel to the a axis. In compound 2, each CuII atom is pentacoordinated, residing in a square pyramidal geometry and generate an infinite two-dimensional (2D) supramolecular structure resulting from CH•••O, NH•••O and OH•••O hydrogen bond interactions. The coordination network 1 and 2, on pyrolyzing, yielded copper oxide nanoparticles, which have been characterized by TEM and powder X-ray diffraction. The catalytic properties of the resulting copper oxide nanoparticles have also been studied for CN cross-coupling reactions with aryl halides. The CN coupling products were obtained in 70–99 % yields.

Temperature‐Dependent Left‐ and Right‐Twisted Conformational Changes in 1:1 Host‐Guest Systems: Theoretical Modeling and Chiroptical Simulations

An efficient strategy for high‐performance chiral materials is to design and synthesize host molecules with left‐ and right‐ (M‐ and P‐) twisted conformations and to control their twisted conformations. For this, a quantitative analysis is required to describe the chiroptical inversion, chiral transfer, and chiral recognition in the host‐guest systems, which is generally performed using circular dichroism (CD) and/or proton nuclear magnetic resonance (1H‐NMR) spectroscopies. However, the mass‐balance model that considers the M‐ and P‐twisted conformations has not yet been established. In this study, we derived the novel equations based on the mass‐balance model for the 1:1 host‐guest systems. Then, we further applied them to analyze the 1:1 host‐guest systems for the achiral calixarene‐based capsule molecule, achiral dimeric zinc porphyrin tweezer molecule, and chiral pillar[5]arene with the chiral and/or achiral guest molecules by using the data obtained from the CD titration, variable temperature CD (VT‐CD), and 1H‐NMR experiments. The thermodynamic parameters (ΔH and ΔS), equilibrium constants (K), and molar CD (Δε) in the 1:1 host‐guest systems could be successfully determined by the theoretical analyses using the derived equations.

Temperature-Dependent Left- and Right-Twisted Conformational Changes in 1:1 Host-Guest Systems: Theoretical Modeling and Chiroptical Simulations.

An efficient strategy for high-performance chiral materials is to design and synthesize host molecules with left- and right- (M- and P-) twisted conformations and to control their twisted conformations. For this, a quantitative analysis is required to describe the chiroptical inversion, chiral transfer, and chiral recognition in the host-guest systems, which is generally performed using circular dichroism (CD) and/or proton nuclear magnetic resonance (1H-NMR) spectroscopies. However, the mass-balance model that considers the M- and P-twisted conformations has not yet been established. In this study, we derived the novel equations based on the mass-balance model for the 1:1 host-guest systems. Then, we further applied them to analyze the 1:1 host-guest systems for the achiral calixarene-based capsule molecule, achiral dimeric zinc porphyrin tweezer molecule, and chiral pillar[5]arene with the chiral and/or achiral guest molecules by using the data obtained from the CD titration, variable temperature CD (VT-CD), and 1H-NMR experiments. The thermodynamic parameters (ΔH and ΔS), equilibrium constants (K), and molar CD (Δε) in the 1:1 host-guest systems could be successfully determined by the theoretical analyses using the derived equations.

Simulation of Vibrational Circular Dichroism Spectra Using Second-Order Møller-Plesset Perturbation Theory and Configuration Interaction Doubles.

We present the first single-reference calculations of the atomic axial tensors (AATs) with wave function-based methods including dynamic electron correlation effects using second-order Møller-Plesset perturbation theory (MP2) and configuration interaction doubles (CID). Our implementation involves computing the overlap of numerical derivatives of the correlated wave functions with respect to both nuclear displacement coordinates and the external magnetic field. Out test set included three small molecules, including the axially chiral hydrogen molecule dimer and (P)-hydrogen peroxide, and the achiral H2O. For our molecular test set, we observed deviations of the AATs for MP2 and CID from that of the Hartree-Fock (HF) method upward of 49%, varying with the choice of basis set. For (P)-hydrogen peroxide, electron correlation effects on the vibrational circular dichroism (VCD) rotatory strengths and corresponding spectra were particularly significant, with maximum deviations of the rotatory strengths of 62 and 49% for MP2 and CID, respectively, using our largest basis set. The inclusion of dynamic electron correlation to the computation of the AATs can have a significant impact on the resulting rotatory strengths and VCD spectra.

Influence of chalcopyrite nanoplatelets on nematic phases of bend-shaped dimeric molecules: Phase diagram, birefringence, and reorientation transition

We investigated the influence of chalcopyrite (CuFeS2) nanoplatelets on the ordering of uniform and twist-bend nematic phases of achiral bend-shaped dimers, employing polarized optical microscopy, optical and electro-optical measurements. Specifically, aliphatic amine surface-functionalized hydrophobic chalcopyrite nanoplatelets were synthesized and characterized by XRD, TEM, and IR-vis-UV spectroscopy. Nanocomposites of the liquid crystal compound 1”,9”-bis(4-cyanobiphenyl-4'-yl)nonane (CB9CB) with the nanoplatelets were prepared. The study encompasses an assessment of the thermodynamic stability of the nanocomposites, constructing the corresponding phase diagram as a function of temperature and nanoplatelet mass fraction. Large phase temperature shifts were observed for minute mass fractions of NPs. Birefringence measurements were performed to investigate the orientational order parameter and the conical tilt angle's dependence on the mass fraction of the nanoplatelets and the temperature. Additionally, we measured a Fréedericksz-like reorientation transition voltage threshold and switching times as functions of the mass fraction and temperature. A huge increase of the voltage threshold was measured in the twist-bend nematic phase. The dependence of the viscoelastic coefficient ζ on NPls' mass fraction was investigated. The splay elastic constant of the helicoidal structure was estimated, using a coarse grain approximation, to be two orders of magnitude higher than in the uniform nematic phase. Finally, in the twist-bend nematic phase, the impact of temperature and nanoplatelets mass fraction on the hysteresis loop of the reorientation transition was investigated.

The infrared spectrum of YI3 in the vapour phase

The vibrational spectrum of the vapour phase above YI3 was measured by infrared spectroscopy. The spectrum revealed four strong bands, three of which could be assigned to the fundamantal infrared active vibrations of the YI3 monomer molecule. The observed frequencies agree very well with quantum-chemical calculations reported in literature. The presence of dimer molecules, the fraction of which is significant in the vapour according to literature, is also discussed in the context of assigning the fourth strong band in the experimental spectrum. Although its position matches well with a strong fundamental of the dimer, its intensity suggest a dimer fraction that is far outside the range for the other rare-earth triiodides.

Composition Heterogeneity of Metal Ions Bound at the Oxygen-Evolving Center of Photosystem II in Living Cells.

Recent resolution advancement of in situ cryo-electron tomography (cryo-ET) and cryo-electron microscopy (cryo-EM) enables us to visualize large enzymes-in-action in atomic detail in their native environments inside living cells, such as photosystem II (PSII) and the ribosome. A variety of crystallographic and cryo-EM structures of PSII have been published for the purified PSII dimeric core complexes by itself, in supercomplexes with photosystem I (PSI) and light-harvesting complexes (LHC), and in megacomplexes with phycobilisome (PBS). In the latter case, two or five copies of asymmetric dimeric PSII molecules are present in highly asymmetric environments that differ from other 2-fold symmetric structures. Previous systematic analysis of X-ray free-electron laser (XFEL) crystal structures of PSII has shown different degrees of composition heterogeneity of metal ion cofactor bound at the oxygen-evolving center (OEC), including between two monomers of the same PSII dimer. This study analyzed the metal ions bound at four OECs in two asymmetric dimeric PSII molecules within in situ cryo-ET structures reported for an asymmetric PBS-PSII-PSI-LHC megacomplex determined in a living organism without purification and shows that composition heterogeneity with reduced metal ion occupancies at the OEC of PSII is a general phenomenon. This finding could have profound implications for spectroscopic interpretations of unpurified PSII samples.

Dimerized small molecule donor enables efficient ternary organic solar cells

Ternary organic solar cells (OSCs) are the feasible and efficient strategy to achieve the high-performance OSCs. It is of great significance to develop a superior third component candidate for constructing efficient ternary OSCs. In this work, we intelligently designed and synthesized a dimerized small molecule donor by connecting two asymmetric small molecule donors with the vinyl group, which is named DSMD-βV. This innovative oligomeric molecule DSMD-βV not only exhibits the complementary absorption and the cascade energy level arrangement with PM6 and BTP-eC9, but also regulates the phase separation micromorphology based on PM6:BTP-eC9. Consequently, PM6:DSMD-βV:BTP-eC9 based ternary device exhibits the improved exciton dissociation, charge transport and decreased recombination, thus achieving a superior power conversion efficiency (PCE) of 18.26 %, surpassing PM6:BTP-eC9 based binary (17.63 %). This work indicates that the dimerized small molecule donor is able to become a promising third component candidate, which also opens up a unique idea for the construction of efficient ternary organic solar cells.

Physicochemical and Spectroscopic Characterization of Glycogen and Glycogen Phosphorylase b Complexes

Glycogen is a natural polysaccharide used as an energy storage macromolecule. The role of glycogen metabolism in type 2 diabetes mellitus has been under investigation for several years, along with its implication in cancer and cardiovascular and neurodegenerative diseases. Previous studies using pig liver glycogen with rabbit muscle glycogen phosphorylase (RMGPb), which catalyzes the first step of glycogen degradation to glucose-1-phosphate, showed that the surface of an average glycogen molecule is covered by a total of 20 RMGPb dimeric molecules. In this work, we selected oyster glycogen (Glyc) to investigate its interaction with RMGPb by employing biophysical techniques. Dynamic, static, and electrophoretic light scattering were used to investigate the solution behaviors and structures of both the Glyc molecule itself and the formed complexes between Glyc and GPb at different mixing ratios. It was established that the interaction between oyster Glyc and RMGPb is similar to that previously reported for pig liver glycogen. Moreover, the structure of the complexed GPb was monitored by fluorescence and FTIR spectroscopy.

Molecular and structural basis of an ATPase-nuclease dual-enzyme anti-phage defense complex

Coupling distinct enzymatic effectors emerges as an efficient strategy for defense against phage infection in bacterial immune responses, such as the widely studied nuclease and cyclase activities in the type III CRISPR-Cas system. However, concerted enzymatic activities in other bacterial defense systems are poorly understood. Here, we biochemically and structurally characterize a two-component defense system DUF4297–HerA, demonstrating that DUF4297–HerA confers resistance against phage infection by cooperatively cleaving dsDNA and hydrolyzing ATP. DUF4297 alone forms a dimer, and HerA alone exists as a nonplanar split spiral hexamer, both of which exhibit extremely low enzymatic activity. Interestingly, DUF4297 and HerA assemble into an approximately 1 MDa supramolecular complex, where two layers of DUF4297 (6 DUF4297 molecules per layer) linked via inter-layer dimerization of neighboring DUF4297 molecules are stacked on top of the HerA hexamer. Importantly, the complex assembly promotes dimerization of DUF4297 molecules in the upper layer and enables a transition of HerA from a nonplanar hexamer to a planar hexamer, thus activating their respective enzymatic activities to abrogate phage infection. Together, our findings not only characterize a novel dual-enzyme anti-phage defense system, but also reveal a unique activation mechanism by cooperative complex assembly in bacterial immunity.

SDS-Assisted Hydrothermal Growth and Photocatalytic Activity of Like-Caviar MoFe<sub>2</sub>O<sub>4</sub> Nanoparticle Decorated with Al<sub>2</sub>O<sub>3</sub>

Like-caviar molybdenum ferrite nanoparticles (MoFe2O4 NPs) have been successfully synthesized via a hydrothermal route in the presence of the negative surfactant (sodium dodecyl sulfate (SDS)). SDS acts as a template, stabilizer, and stops the aggregating process through storage. The mean crystal size of MoFe2O4 NPs rises with decorating it with Al2O3. Based on SEM analysis, the shapes of MoFe2O4, Al2O3, and their composite demonstrated like-caviar, like-brain cells, and like-grains, respectively. Al2O3 has been chosen to incorporate with spinel MoFe2O4 to make it color more light, this crucial step is necessary to enhance their optical characteristics. FTIR spectra observed the MoFe2O4 NPs are inverse spinel. The photo-decolorization test employs indigo carmine (IC) as a model pollutant. The quantum yields (Φ) of IC dye decolorization with studied photocatalysts are low, which may be created by quencher materials, dimerization of dye molecules, and photophysical deactivation processes (ISC process). Moreover, the photocatalytic activity of using MoFe2O4 raised after being decorated with alumina, which revealed an increase in the surface acidity, hydroxyl group adsorption, size, band gap, pHpzc of MoFe2O4 from 2.9–3.6 to 4.2–5.9 after decorated alumina. This pH is suitable for decolorizing IC dye, which has a pH of solution equal to 5.3.

Electronic Couplings and Conversion Dynamics between Localized and Charge Transfer Excitations from Many-Body Green's Functions Theory.

We investigate the determination of electronic coupling between localized excitations (LEs) and charge-transfer (CT) excitations based on many-body Green's functions theory in the GW approximation with the Bethe-Salpeter equation (GW-BSE). Using a small molecule dimer system, we first study the influence of different diabatization methods, as well as different model choices within GW-BSE, such as the self-energy models or different levels of self-consistency, and find that these choices affect the LE-CT couplings only minimally. We then consider a large-scale low-donor morphology formed from rubrene and fullerene and evaluate the LE-CT couplings based on coupled GW-BSE-molecular mechanics calculations. For these disordered systems of bulky molecules, we observe differences in the couplings based on the Edmiston-Ruedenberg diabatization compared to the more approximate Generalize Mulliken-Hush and fragment charge difference diabatization formalisms. In a kinetic model for the conversion between LE and CT states, these differences affect the details of state populations in an intermediate time scale but not the final populations.

Steric Effects of Alcohols on the [Mn4O4] Cubane-Type Structures

[M4O4] (M = 3d transition metal) represents an interesting class of compounds featuring cubane-type molecular structures, and particularly, [Mn4O4] cubanes or their derivatives attract much attention by virtue of their potential applications as single-molecule magnets (SMMs) or catalysts. However, the rational design of desired cubane-related structures is still a challenging subject due to the lack of readily available methods to effectively tune the construction patterns of the molecule assembly. In this work, we report the employment of different alcohols to prepare three cubane-related molecules, Mn2(dhd)4(iPrOH)2 (1), Mn4(dhd)4(OEt)4(EtOH)4 (2) and Mn4(dhd)6(OMe)2(MeOH)2 (3) (dhd = 5,5-dimethyl-2,4-hexanedione). Interestingly, the bulkiest iPrOH leads to simple rhombic dimer molecule 1. It can be deemed a rudimentary structure oftetranuclear [Mn4O4] cubane 2, which can be realized by the use of less bulky EtOH. In addition, the least bulky MeOH promotes the assembly of the cubanes, eventually bringing about defective dicubane molecular cluster 3. The accurate crystal structures of 1–3 were modeled by single-crystal X-ray diffraction, and their electronic structures were investigated through absorption spectroscopy coupled with theoretical calculations. Overall, this work demonstrates a systematic study on controlling cubane-type structures of Mn-based compounds by applying different solvents, which provides a new means to design functional molecules for specific applications.

Synthesis, structure, hirshfeld surface analysis and antibacterial activities of [Cd(2-ampy)3(NCS)(μ1,5-SCN)]2 and [Cd(4-ampy)2(μ1,5-dca)2]n complexes (2-ampy = 2-aminopyridine, 4-ampy = 4-aminopyridine, NCS = thiocyanate, dca = dicyanamide)

The complexes [Cd(2-ampy)3(NCS)(μ-SCN)]2 (1) and [Cd(4-ampy)2(μ1,5-dca)2]n (2) were synthesized and characterized using single crystal XRD. Complex 1 has a dimer structure with a triclinic crystal system and space group P1¯, whereas complex 2 has a polymer structure with a monoclinic crystal system and space group P21/c. Hirshfeld surface analysis of complex 1 showed the presence of S⋯N–H and N–H–S interactions between dimer molecules and intramolecular hydrogen bonds N–H⋯N. In complex 2, the analysis showed the polymer coordination chain bonds between Cd(II) ions with N atoms from dicyanamide and intermolecular hydrogen bonds of N–H⋯N. In vitro antibacterial testing for both complexes against Escherichia coli (gram-negative) and Staphylococus aureus (gram-positive) showed a higher inhibition zone diameter than the constituent reactants, where complex 2 had the a higher antibacterial activity.