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The most significant factor in the design of high-performance nonlinear optical (NLO) materials is electronic symmetry, which directly influences hyperpolarizability and second harmonic generation (SHG) response. This work presents two isostructural one-dimensional coordination complexes, {[Co₂(CMP)₂(BIPY)₂(H₂O)₆]·11H₂O}_n (I) and {[Ni₂(CMP)₂(BIPY)₂(H₂O)₆]·11H₂O}_n (II), (CMP = Cytidine Monophosphate, BIPY = 4,4'-bipyridine), crystallized in the noncentrosymmetric (NCS) P2₁ space group. The cobalt-based complex (I) establishes an NCS environment due to its pronounced octahedral distortion and lower electronic symmetry, coupled with intrachain hydrogen bonding and π-π stacking, resulting in enhanced hyperpolarizability and a robust second-harmonic generation response. Conversely, the nickel-based complex (II) demonstrates comparatively weaker NLO characteristics attributable to its higher symmetry. Experimental and theoretical findings have established that the superior NLO performance of complex (I) is intrinsically linked to its low symmetry, narrow band gap, and significant intermolecular interactions. This research demonstrates that disrupting electronic symmetry can significantly amplify the nonlinear optical response through supramolecular architecture in coordination polymers. Show less

Hepatocellular carcinoma (HCC) is a highly refractory malignancy, for which treatment relies on molecule targeted therapy and/or conventional chemotherapy in clinic. However, these approaches generally suffer from limited efficacy or severe toxicity, restricting their applications. Guided by the targeted drug conjugate (TDC) strategy, the pharmacophore of lenvatinib was modified by incorporating DN604 (C₆H₁₀N₂O₅Pt), a carboplatin analogue, to generate a Pt(II) complex Len-604 (C₃₀H₃₃ClN₈O₉Pt). This compound was found to possess the specific capability to bind to fibroblast growth factor receptor 4 (FGFR4) protein both in vitro and in vivo, facilitating targeted delivery of DN604 to tumor sites and consequently triggering serious DNA damage in cancer cells. It exhibited potent cytotoxicity against human hepatocellular carcinoma cell lines HUH-7 and SMMC-7721, with IC₅₀ values of 5.62 and 5.64 μM, respectively. Significantly, in HUH-7 xenograft models, Len-604 exhibited stronger antitumor activity than lenvatinib, while showing lower toxicity than cisplatin and its physical mixture with lenvatinib. Show less

A molecular Co^III complex (1), supported by a 14-membered macrocyclic ligand, was developed. The oxygen reduction reaction (ORR) catalyzed by 1 was investigated under electrochemical and spectrochemical conditions in acetonitrile, using trifluoroacetic acid (TFAH) as the proton source, and revealed selective catalytic 4e^-/4H⁺ reduction in both cases. Kinetic analyses revealed a first-order dependence on the concentrations of both catalyst and O₂, but no dependence on TFAH or decamethylferrocene (under chemical conditions). The catalytic rate constant was determined to be 3.6 × 10³ M^-1 s^-1 under electrochemical and 90 M^-1 s^-1 under spectrochemical conditions. A reported Co(III) complex (2), featuring a bis-pyridine-dioxime ligand architecture, also catalyzed the 4e^-/4H⁺ reduction of O₂ but displayed first-order dependence on catalyst, TFAH, and O₂. These results suggest that variations in the coordination environment around the Co center lead to distinct ORR mechanisms, despite identical product selectivity. Complex 1 exhibited an effective overpotential of 0.78 V, which is 240 mV lower than that of 2 (η_eff = 1.02 V), underscoring the role of ligand architecture in tuning the catalytic overpotential. Overall, this study underscores the pivotal role of ligand design in shaping ORR kinetics, mechanism, and efficiency, offering valuable insights for the development of ORR catalysts. Show less

The oxygen evolution reaction under neutral conditions remains a significant challenge due to sluggish kinetics and catalyst instability, largely stemming from inefficient proton management. Inspired by the proton-coupled electron transfer (PCET) networks in the oxygen-evolving complex of photosystem II, we report the rational design of two bioinspired cubane-type tetranuclear copper catalysts, Cu₄(L_Gly)₄ and Cu₄(L_Glu)₄, functionalized with amino acid derivatives. Electrochemical studies reveal that the glutamate-modified Cu₄(L_Glu)₄ outperforms its glycine counterpart, achieving a remarkable turnover frequency (TOF) of 9.64 ± 0.07 s^-1 at a low overpotential of 0.63 V in phosphate buffer solution (pH 7.30). Differential pulse voltammetry and mechanistic investigations indicate a PCET nature for the copper redox transitions. Density functional theory calculations demonstrate that the carboxylate group of the glutamate residue acts as an intrinsic proton relay, significantly lowering the energy barrier for the critical O-O bond formation step. Furthermore, a photovoltaic-electrocatalytic (PV-EC) device utilizing the Cu₄(L_Glu)₄ anode achieves a solar-to-hydrogen (STH) conversion efficiency of 10.24% under neutral conditions, one of the highest reported values without a strong alkaline environment. This work underscores the critical role of second-sphere proton-transfer functionality in designing efficient molecular catalysts for PCET-driven energy conversion reactions. Show less

Understanding ligand properties is essential for computational high-throughput screening of transition metal complexes. However, ligand properties such as net charge and other information such as their application area are often absent or inconsistently recorded in crystallographic datasets. Here, we construct a ligand dataset from 126,985 mononuclear transition metal complexes curated from the Cambridge Structural Database. Using an iterative charge-balancing workflow that combines complex charges, metal oxidation states, and consensus across crystallographic observations, we confidently assign net charges to 66,810 ligands among 94,581 identified unique ligand structures to curate the Boston Open-Shell Ligand (BOS-Lig) dataset. The workflow assigns ligand charges in homoleptic complexes first and then iteratively propagates these assignments across heteroleptic environments, allowing charges to be inferred even when direct charge information is unavailable. We analyze cases where simple heuristics such as the octet rule would have failed and introduce a purity metric to identify when our charge assignments may be incorrect. Each ligand is also classified in terms of its metal coordinating atoms and whether there are multiple variants (i.e., hemilability). We then link complexes to their associated journal abstracts and apply a topic-modeling workflow to link 25,146 ligands with functional application areas spanning reactivity, redox chemistry, biological chemistry, and photophysical chemistry. Together, we provide an experimentally grounded dataset of ligand chemical space that connects charge and functional application as a foundation for computational screening and data-driven ligand design. Show less

An integrated multimodal imaging workflow of cryogenic super-resolution fluorescence microscopy and soft X-ray tomography, Orbitrap secondary ion mass spectrometry, and inductively coupled plasma-mass spectrometry has revealed the unexpected targeting of a half-sandwich cyclopentadienyl Rh(III) phenylazopyridine anticancer complex to cellular lipid membranes and lipid droplets. The complex accumulates in plasma membranes with a surprisingly intense switch-on luminescence in living cancer cells, drives remodeling of lipid droplet architecture, and penetrates deeply into lipid-rich tissue environments. DFT modeling shows strong supramolecular interactions between the complex and glycerophosphorylcholine lipids. Show less

Defense-associated reverse transcriptases (DRTs) are widespread bacterial anti-phage systems that use unconventional mechanisms of polynucleotide synthesis. We show that DRT3, which comprises two distinct RTs (Drt3a and Drt3b) and a noncoding RNA (ncRNA), synthesizes alternating poly(GT/AC) double-stranded DNA. Cryo-electron microscopy structures at 2.6 Å resolution reveal a D3-symmetric 6:6:6 complex of Drt3a, Drt3b, and ncRNA. Drt3a produces the poly(GT) strand using a conserved ACACAC template within the ncRNA. Notably, Drt3b synthesizes a complementary, protein-primed poly(AC) strand in the complete absence of a nucleic acid template, using conserved active site residues specific to Drt3b to enforce precise base alternation. These findings expand the functional landscape of nucleic acid polymerases, revealing a protein-templated mechanism for sequence-specific DNA synthesis. Show less

ABSTRACT Understanding how metals coordinate to organic ligands is a precondition for the rational design of metal complexes and catalysts. Whereas certain types of ligands are capable of just one easy‐to‐predict coordination modality, others may present tens and sometimes even hundreds of coordination options (mono‐, bi‐, or polydentate), and predicting the correct one may be a challenge even to seasoned chemists. The current paper describes a “hybrid” computational approach in which a Machine Learning, ML, algorithm learns to predict complex coordination patterns using knowledge‐based “rules” derived from the Cambridge Structural Database, CSD. This model is applicable to a broad scope of ligands (including hemilabile and haptic ones as well as those with denticity > 6) and different metals at different oxidation states. The algorithm's code is disclosed and can be readily deployed in RDKit via our RDMetallics python‐wrapper. It is also deployed as a publicly accessible web portal for demonstration and use. Show less

Abstract Most clinically used chemotherapeutic agents act by inducing apoptosis. However, their clinical effectiveness is often limited by poor therapeutic efficacy and the rapid development of drug resistance. In contrast, oncosis, as an inflammatory form of cell death independent of adenosine triphosphate (ATP) and apoptotic pathways, exhibits unique advantages in overcoming tumor drug resistance and regulating anti‐tumor immune responses. Herein, we present the first iridium(III)‐based immunogenic oncosis inducers designed to concurrently induce oncosis and activate the cGAS–STING pathway, thereby bridging chemotherapy with immunotherapy. Through a bioisosteric design strategy, we identified benzoselenazole and benzothiazole derivatives as key pharmacophores for triggering oncosis. These iridium(III)‐based oncosis‐inducers rapidly disrupt mitochondrial architecture, induce oxidative stress, and promote Ca(II) release, which subsequently activate calpain and porimin to initiate oncosis in multidrug‐resistant cancer cells. Transcriptomic profiling further revealed their ability to regulate actin cytoskeleton organization, modulate ABC transporter activity, and affect glycolysis/gluconeogenesis. Notably, the metal complexes induce mitochondrial swelling and mt‐DNA damage, leading to robust activation of the cGAS–STING innate immune pathway and eliciting a strong anticancer immune response. Based on these multimodal mechanisms, the Ir(III)‐based immunogenic oncosis inducers were able to effectively kill drug‐resistant cancer cells and enhance the anticancer immune response in tumor mouse models. TLDR: The first iridium(III)-based immunogenic oncosis inducers designed to concurrently induce oncosis and activate the cGAS-STING pathway are presented, thereby bridging chemotherapy with immunotherapy. Show less

Encouraged by the promising anticancer activity of a iodidogold(I)-N-heterocyclic carbene (NHC) complex with a 1,3-diethyl-4-anisyl-5-(4-chlorophenyl)imidazol-2-ylidene ligand system, a series of new gold(I), gold(III) and platinum(II) complexes coordinated to this ligand system were designed, prepared, and characterized using NMR spectroscopy and mass spectrometry methods. A preliminary anticancer screening of the complexes using four esophageal adenocarcinoma (EAC) cell lines showed promising activities for the cationic triphenylphosphino-NHC-gold(I) and bis-NHC-gold(I) complexes, accompanied by strong antiproliferative, colony-, and spheroid-forming inhibitory effects. The compounds were relatively less toxic to the normal esophageal cell line Het-1A and the monocyte cell line THP-1. Moreover, these compounds induced caspase 3/7 activity and downregulated anti-apoptotic proteins (Bcl-XL, Bcl-2, and Mcl-1) in EAC cells. Further, the cell cycle promoter cyclin D1 was suppressed by these NHC-gold(I) complexes. Finally, we observed strong reactive oxygen species (ROS) induction in EAC cells with NHC-gold(I) complexes 8 and 11. TLDR: A preliminary anticancer screening of the complexes using four esophageal adenocarcinoma (EAC) cell lines showed promising activities for the cationic triphenylphosphino-NHC-gold(I) and bis-NHC-gold(I) complexes, accompanied by strong antiproliferative, colony-, and spheroid-forming inhibitory effects. Show less

The synthesized Oestradiol-functionalized Au( i ) bis(1,2,3-triazol-5-ylidene) complex exhibits high cytotoxicity and a 7-fold increased cellular uptake in ERα-positive breast cancer cells (MCF-7) compared to its oestradiol-free analogue. Show less

Colorectal cancer (CRC) remains a major global health challenge, in which chronic inflammation and redox dysregulation are key drivers of tumor progression. Here, we report a rationally designed family of NSAID-derived alkyne ligands coordinated to JohnPhos-gold(I) fragments, affording eight new alkynyl gold(I) derivatives. Complexes based on naproxen, ibuprofen, and salicylic acid derivatives display potent antiproliferative activity against Caco-2/TC7 colon cancer cells, outperforming oxaliplatin and being comparable to auranofin, while showing markedly reduced cytotoxicity in breast cancer lines and nonmalignant cells, thus indicating promising selectivity. Mechanistic studies revealed that the most active complex, [Au(L1)JP] (1), which contains a naproxen-derived alkyne, inhibits thioredoxin reductase (TrxR), triggers ROS overproduction, disrupts mitochondrial membrane potential, and induces G1-phase arrest while only marginally increasing apoptosis. This suggests the involvement of additional forms of cell death or cytostatic effects. Additionally, complex 1 selectively inhibits the enzyme cyclooxygenase-2 (COX-2) over COX-1 and reduces IL-8 expression without affecting PTGS2 transcription, highlighting a post-transcriptional anti-inflammatory action. These results support NSAID-derived alkynyl gold(I) complexes as promising multitarget agents for colorectal cancer intervention, combining disruption and COX-2 modulation. Show less

Immunotherapy represents a paradigm shift in oncology, rooted in a century of evolving scientific understanding and clinical application. From the pioneering use of Coley’s toxins in the late nineteenth century to the introduction of cytokine-based interventions, the trajectory of immunotherapeutic approaches has paralleled advancements in immunology and molecular biology. This review comprehensively examines the historical development and progressive refinement of immunotherapy for cancer, charting the transition from non-specific immune stimulation to targeted immune modulation. Central to this discussion are the sophisticated mechanisms by which tumour cells evade immune detection and destruction. These include downregulation of antigen presentation machinery, secretion of immunosuppressive cytokines, recruitment of regulatory T cells and myeloid-derived suppressor cells, and exploitation of immune checkpoint pathways, particularly CTLA-4 and PD-1/PD-L1 axes. The advent of immune checkpoint inhibitors has yielded durable clinical responses in diverse malignancies, substantiating their role as foundational agents in cancer therapy. Nonetheless, both primary and acquired resistance to immune checkpoint inhibition remain significant clinical obstacles. Resistance mechanisms are multifactorial, involving tumour-intrinsic genetic alterations, modulation of the tumour microenvironment, and adaptive changes in immune cell phenotypes. Contemporary research endeavors are directed at overcoming these barriers, including the optimization of combinatorial regimens, development of next-generation checkpoint modulators, tumour-specific vaccines, and the integration of adoptive cell therapies. Future directions in cancer immunotherapy are poised to leverage advances in systems biology, genomics, and single-cell technologies to individualize interventions and enhance therapeutic efficacy. Ultimately, a comprehensive delineation of tumour-immune interactions will underpin the next generation of rational, effective, and durable cancer immunotherapies. Show less

Including energy dynamics in research could improve our understanding of diseases and of the healing processes that sustain health. Including energy dynamics in research could improve our understanding of diseases and of the healing processes that sustain health. Show less

Coacervates are dense aqueous phases that form by liquid-liquid phase separation. Seven Pt(II) complexes with different charges and nucleotide reactivities were examined for their ability to induce coacervate formation in a 21-mer single-stranded DNA (ssDNA). Only AMPZ ([cis-{Pt(NH₃)₂}₂(μ-pyrazolato)(μ-OH)](NO₃)₂), a cationic dinuclear Pt(II) complex, efficiently induced coacervate formation in ssDNA containing only thymine (T21-DNA). AMPZ has very low reactivity with thymine but relatively high reactivity with guanine, and when three of the thymines in T21-DNA were substituted with a guanine to produce T18-G3-DNA, the resulting coacervate was observed to undergo gelation via the formation of an extensive Pt-DNA coordination-bonded network. We then examined the construction of coacervates that comprise multiple phases by adding AMPZ to a mixture of two types of ssDNAs, a highly reactive T10-G11-DNA and a minimally reactive T21-DNA, and found that two distinct assembly states─a cell mimetic assembly and a DNA-encapsulating gel─could be formed. Show less

Biomedical research benefits from the rapid growth and diversity of experimentally detected protein-protein interactions (PPIs) by gaining important biological insights. However, increasingly dense PPI networks can be challenging to interpret and apply. The 2025 update of the Integrated Interactions Database (IID) enhances accessibility and utility through several new features. We identify and incorporate network structural components from co-purified protein sets, as well as curated and predicted complexes, enabling users to explore network organization beyond binary interactions. Functional, pathway, and disease associations of these components can be analyzed, enabling interactions to be grouped into higher-order structures with known or provisional biological roles. Users can now filter interactions by five detection types: pairwise, co-purification, colocalization, proximity, and other evidence. To extend the value and information of predicted interactions, we include interaction interface predictions for 53 647 PPIs, generated using the MEGADOCK docking algorithm, adding molecular detail for structural biology and variant impact studies. Finally, we map PPIs to 15 immune cell types and 12 additional normal tissues, offering tissue-specific views of interaction networks increasingly relevant in disease and immunology research. IID 2025 now includes over 1 million experimentally detected human PPIs, representing an 83% increase from the previous release, alongside expanded non-human networks. The portal remains publicly available at https://ophid.utoronto.ca/iid. Show less

Luminescence probes targeting specific membrane receptors are powerful imaging tools for cancer detection and image-guided surgical navigation. However, conventional single receptor targeting probes often suffer from low specificity and high background interference, limiting their effectiveness in accurately imaging cancer cells. Herein, we developed two dual receptor-mediated luminescent iridium(III) complexes for precise cancer cell imaging using a bioorthogonal activation approach. We strategically designed these probes to target two different biomarkers on the membrane: the benzenesulfonamide group in the N^N ligand targets carbonic anhydrase IX (CAIX), while the biotin moiety linked to endo-9-hydroxymethyl-bicyclo[6.1.0]non-4-yne (BCN) targets the biotin receptor. Complexes 1 and 2 exhibit 16- and 29-fold luminescence enhancement after reacting with BCN-Biotin, with rapid second-order rate constants (k₂) of 3.5 × 10⁵ M^-1 s^-1 and 8.7 × 10³ M^-1 s^-1, respectively. Notably, complex 2 can sensitively and specifically detect cancer cells overexpressing CAIX, as verified by multiple biochemical experiments. On the other hand, complex 2 showed negligible luminescence in cell lines with low expression of CAIX, demonstrating its ability to discriminate cancer cells. Overall, this work demonstrates the promising potential of dual receptor-mediated iridium(III) complexes based on the bioorthogonal activation strategy for the accurate and specific imaging of cancer cells. Show less

Debate over the electronic structure of Cu^III complexes has intensified in recent years, focusing primarily on whether the [Cu(CF₃)₄]^- moiety should be described as a classical Werner-type 3d⁸ Cu^III complex or as a 3d¹⁰ Cu^I inverted ligand field framework. The copper periodate complex [Cu(HIO₆)₂]^5-, discovered in 1937, has long been regarded as a 3d⁸ Cu^III species and sometimes used as a reference 3d⁸ Cu^III complex in oxidation state assignments for Cu-containing metalloenzymes. Nevertheless, its detailed electronic structure remains unexplored. Herein, we revisit the oxidation state of [Cu(HIO₆)₂]^5- by means of X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and density functional theory calculations. The obtained results show that the oxidation state of the Cu center in [Cu(HIO₆)₂]^5- lies at the boundary between the classical Werner-type and inverted ligand field regimes. This study thus demonstrates that categorizing the oxidation state of Cu^III complexes as either 3d⁸ or 3d¹⁰ configurations is often inadequate; instead, the existence of electronic states at the boundary between these two limiting cases should be recognized. Show less

Atomically precise Au₂₅ nanoclusters are ideal catalyst models for unraveling the nanozyme structure-activity relationship due to their well-defined structures and tunable electronic properties. Herein, ab initio molecular dynamics (AIMD) simulations combined with density functional theory (DFT) calculations were employed to systematically investigate the ligand removal behavior and peroxidase (POD)-like catalytic activity of Au₂₅ nanoclusters modified with phosphine (PR), thiol (SR), alkynyl (C≡CR), and N-heterocyclic carbene (NHC) ligands. Constrained AIMD (cAIMD) simulations revealed that all clusters preferentially remove halogen ligands (Cl/Br) with free energy barriers below 0.25 eV, while NHC and phosphine ligands exhibit stronger binding stability with the Au core. The exposed low-coordination gold sites upon halogen removal display excellent POD-like activity, wherein the second *OH reduction (or the second TMB oxidation) is determined to be the rate-determining step (RDS). Among them, [Au₂₅(NHC)₁₀(Br)₆]²⁺-top (removal of Br at the top coordination site) exhibits the most optimal activity with a moderate RDS barrier (0.83 eV) owing to its isolated active site and higher d-band center that balance *OH adsorption and the catalytic activity. This study clarifies the structure-activity relationship of atomically precise Au₂₅ nanoclusters in the peroxidase-like catalysis, providing a quantitative basis for high-efficiency Au-based nanozyme design. Show less

Liquid-liquid phase separation (LLPS) is a fundamental biophysical process driving the formation of dynamic biomolecular condensates, which spatially organize cellular biochemistry without membrane delimitation. These condensates arise from multivalent, weak interactions among intrinsically disordered proteins, modular interaction motifs, and RNA scaffolds, enabling highly tunable and reversible compartmentalization of biomolecules. This phase behavior regulates critical cellular functions such as gene expression, signal transduction, and stress response, while its dysregulation contributes to pathological aggregation and disease. Recent advances leverage LLPS principles to design synthetic condensates with controllable composition, properties, and activities. Combining structural insights, quantitative phase behavior, and synthetic biology tools, engineered condensates have been developed for enhanced catalysis, metabolic control, targeted drug delivery, and biosensing. This review summarizes the molecular mechanisms, design strategies, and translational prospects of LLPS-mediated condensates, thereby paving the way for future exploration at the interface of cellular biophysics and bioengineering. Show less

Zinc is a crucial element in cellular processes, and its homeostasis has intricate relationships with the initiation, progression, and therapeutic intervention of cancer. Activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has been proven to be an effective strategy for cancer immunotherapy. Herein, we report four phosphorescent iridium complexes (Ir1–Ir4) with zinc chelating ligands. Among them, Ir1 can bind and image mitochondrial chelatable zinc ions via phosphorescence-lifetime responses, consequently modulating the expression of zinc-regulatory proteins. Furthermore, the in situ formed heteronuclear metal complex Ir1-Zn2 shows nuclease mimetic activities, capable of hydrolyzing mitochondrial DNA (mtDNA) to release mtDNA fragments for the activation of the cGAS-STING pathway. In conclusion, we designed a mitochondria-targeting phosphorescent Ir(III) complex with dual functions in dysregulation of zinc homeostasis and generation of nuclease in situ, which provides an innovative approach to stimulate the cGAS-STING pathway. Show less

Four novel gold(I) N-heterocyclic carbene (NHC) complexes were synthesized and characterized; they are tuned in terms of the aromatic extension of the NHC scaffold and two of them contain a thiosugar residue to enhance their cellular uptake. To verify their potential interaction with human serum albumin (HSA), ESI-MS interaction analysis and fluorescence titrations were performed. Biological studies were carried out to evaluate their possible cytotoxic effect on three ovarian cancer cell lines, i.e., A2780 (both sensitive and cisplatin-resistant), and SKOV-3. Confocal microscopy and fluorescence-activated cell sorting tests were also carried out for the four complexes. Thiosugar conjugation proved to be an effective strategy to enhance potency and selectivity, resulting in a considerable improvement compared to the corresponding complexes lacking the thiosugar moiety. Furthermore, six bioconjugates containing targeting peptides were synthesized; in most cases, no significant improvement in either cytotoxic activity or selectivity was observed, except for the LHRH peptide conjugates, which showed a slight enhancement in both cytotoxicity and selectivity compared to the unconjugated complexes. Show less