Highly Anisotropic Pd2Lab2Lcc2 and Pd2Lab2Lcd2 Type Cages by Heteromeric Completive Self-Sorting.

Pd(II)-based low-symmetry coordination cages possessing anisotropic cavities are of great interest. The common strategies employed to achieve such cages utilize either more than one type of symmetrical ligands (e.g., Laa, Lbb, etc.) or only one type of unsymmetrical ligand (e.g., Lab). To significantly enhance the anisotropy, we have designed two unsymmetrical bidentate ligands i.e., Lab and Lcd, aiming a low-symmetry Pd2Lab2Lcd2-type cage. It was accomplished by high-fidelity integrative self-sorting of two different low-symmetry cages having Pd2Lab4 and Pd4Lcd8-type architectures (homoleptic complexes of the designed ligands). Structural constraints and geometry complementarity in the ligand design drive the non-statistical exclusive self-assembly of the Pd2Lab2Lcd2-type cage. By taking advantage of the complemental geometries between ligands, a low-symmetry Pd2Lab2Lcc2-type cage was also obtained. Heteromeric completive self-sorting of three homoleptic assemblies (Pd2Lab4, Pd4Lcc8 and Pd4Lcd8-type cages) into an exclusive mixture of Pd2Lab2Lcd2 and Pd2Lab2Lcc2-type mixed ligated assemblies was demonstrated through cage-to-cage transformations.

Customizing pyridinic nitrogen coordination in Ni-N-C for electrocatalytic CO2reduction towards CO.

Nickel anchored N-doped carbon electrocatalysts (Ni-N-C) are rapidly developed for the electrochemical reduction reaction of carbon dioxide (CO2RR). However, the high-performanced Ni-N-C analogues design for CO2RR remains bewilderment, for the reason lacking of definite guidance for its structure-activity relationship. Herein, the correlation between the proportion of nitrogen species derived from various nitrogen sources and the CO2RR activity of Ni-N-C is investigated. The x-ray photoelectron spectroscopy (XPS) spectrum combined with the CO2RR performance results show that pyridinic-N content has a positive correlation with CO2RR activity. Moreover, density functional theory (DFT) demonstrates that pyridinic-N coordinated Ni-N4sites offers optimized free energy and favorable selectivity towards CO2RR compared with pyrrolic-N. Accordingly, Ni-Na-C with highest pyridinic-N content (ammonia as nitrogen source) performs superior CO2RR activity, with the maximum carbon monoxide faradaic efficiency (FECO) of 99.8% at -0.88 V vs. RHE and the FECOsurpassing 95% within potential ranging of -0.88 to -1.38 V vs. RHE. The building of this parameter for CO2RR activity of Ni-N-C give instructive forecast for low-cost and highly active CO2RR electrocatalysts.

Multifunctional Film Assembled from N-Doped Carbon Nanofiber with Co-N4-O Single Atoms for Highly Efficient Electromagnetic Energy Attenuation.

Single-atom materials have demonstrated attractive physicochemical characteristics. However, understanding the relationships between the coordination environment of single atoms and their properties at the atomic level remains a considerable challenge. Herein, a facile water-assisted carbonization approach is developed to fabricate well-defined asymmetrically coordinated Co-N4-O sites on biomass-derived carbon nanofiber (Co-N4-O/NCF) for electromagnetic wave (EMW) absorption. In such nanofiber, one atomically dispersed Co site is coordinated with four N atoms in the graphene basal plane and one oxygen atom in the axial direction. In-depth experimental and theoretical studies reveal that the axial Co-O coordination breaks the charge distribution symmetry in the planar porphyrin-like Co-N4 structure, leading to significantly enhanced dielectric polarization loss relevant to the planar Co-N4 sites. Importantly, the film based on Co-N4-O/NCF exhibits light weight, flexibility, excellent mechanical properties, great thermal insulating feature, and excellent EMW absorption with a reflection loss of - 45.82 dB along with an effective absorption bandwidth of 4.8 GHz. The findings of this work offer insight into the relationships between the single-atom coordination environment and the dielectric performance, and the proposed strategy can be extended toward the engineering of asymmetrically coordinated single atoms for various applications.

Interleg coordination in free-walking bug Erthesina fullo (Hemiptera: Pentatomidae).

Insects can adapt their walking patterns to complex and varied environments and retain the ability to walk even after significant changes in their physical attributes, such as amputation. Although the interleg coordination of intact insects has been widely described in previous studies, the adaptive walking patterns in free-walking insects with amputation of 1 or more legs are still unclear. The pentatomid bug Erthesina fullo exhibits a tripod gait, when walking freely on horizontal substrates, like many other insects. In this study, amputations were performed on this species to investigate changes in interleg coordination. The walking parameters were analyzed, such as the locations of touchdown and liftoff, cycle period, walking speed, and head displacement of intact and amputated insects. The results show that E. fullo displays adaptive interleg coordination in response to amputations. With 1 amputated leg, bugs changed to a 3-unit gait, whereas with 2 amputated legs they employed a wave gait. These data are helpful in exploring the motion mode control in walking insects and provide the theoretical basis for the gait control strategy of robots, when leg failure occurs.

From Warm to Cold: Feeding Cold Milk in Preterm Infants with Uncoordinated Oral Feeding Patterns.

Objective: Premature infants frequently face feeding challenges due to disrupted coordination of sucking, swallowing, and breathing, increasing their risk of dysphagia. There are few effective treatment options available for these infants. In adults experiencing dysphagia, consuming cold foods or liquids can be an effective strategy. This method stimulates the sensory receptors in the pharyngeal mucosa, promoting safer and more effective swallowing. We have previously demonstrated that short-duration feeding (5 swallows) with cold liquid significantly reduces dysphagia in preterm infants; however, the impact of extended cold milk feeding remains unexplored. This study aims to assess the safety of cold milk feedings in preterm infants diagnosed with uncoordinated feeding patterns and its effect on feeding performance. Study Design: Preterm infants with uncoordinated feeding patterns (n=26) were randomized to be fed milk at either room or cold temperatures using an experimental, randomized crossover design. We monitored axillary and gastric content temperatures, mesenteric blood flow, and feeding performance. Result: The findings suggest that preterm infants can safely tolerate cold milk without any clinically significant changes in temperature or mesenteric blood flow, and it may enhance certain aspects of feeding performance. Conclusion: These results suggest that cold milk feeding could be a safe therapeutic option for preterm infants. These results highlight the potential for further comprehensive studies to explore the use of cold milk as an effective therapeutic approach for addressing feeding and swallowing difficulties in preterm infants. Registered at clinicaltrials.org #NCT04421482.

Actual and perceived motor competence in children with motor coordination difficulties: Effect of a movement-based intervention.

BACKGROUND: The present study analyses the effect of a Movement-Based Intervention to improve Actual and Perceived Motor Competence in children with probable Developmental Coordination Disorder aged four and six years. METHODS AND PROCEDURES: A longitudinal pre-experimental study was designed with measurements conducted at pre-test, post-test and follow-up (after 5 months without intervention). The group, composed of children with probable Developmental Coordination Disorder or low motor competence, consisted of 57 participants, and the duration of a Movement-Based Intervention was 27 sessions allocated in nine weeks. OUTCOMES AND RESULTS: Actual Motor Competence was evaluated with the Movement Assessment Battery for School children and Perceived Motor Competence with Pictorial Scale of Perceived Motor Skill Competence for Children. The results showed significant improvements in both study variables (Actual Motor Competence and Perceived Motor Competence), both at post-test and follow-up, five months after the end of the intervention. In conclusion, a Movement-based Intervention is effective in improving Actual and Perceived Motor Competence in the participants of this research, children with low motor competence or probable Developmental Coordination Disorder. WHAT THIS PAPER ADDS: Considering the improvements observed after the program in Spanish sample, it seems that the usual practice in Early Childhood Education in our context may not be sufficient, i.e., it may not provide children with the necessary support (number of lesson and time) and appropriate learning contexts to promote the development of their motor skills. Considering the results, this study suggests that using an Movement-Based Intervention with an appropriate pedagogical approach, and offering different learning opportunities to children according to their needs, could positively influence their Actual and Perceived Motor Competence, and could motivate them towards future practice.

Co2+ coordination-assisted molecularly imprinted covalent organic framework for selective extraction of ochratoxin A.

Covalent organic frameworks (COFs) are attractive materials for sample pretreatment due to their tunable structures and functions. However, the precise recognition of contaminant in complex environmental matrices by COFs remains challenging owing to their insufficient specific active sites. Herein, we report Co2+ coordination-assisted molecularly imprinted flexible COF (MI-COF@Co2+) for selective recognition of ochratoxin A (OTA). The MI-COF@Co2+ was prepared via one-step polymerization of 3,3-dihydroxybenzidine, 2,4,6-tris(4-formylphenoxy)- 1,3,5-triazine, Co2+ and template. The flexible units endowed COFs with the self-adaptable ability to regulate the molecular conformation and coordinate with Co2+ to locate the imprinted cavities. The coordination interaction greatly improved the adsorption capacity and selectivity of MI-COF@Co2+ for OTA. The prepared MI-COF@Co2+ was used as solid phase extraction adsorbent for high-performance liquid chromatography determination of OTA with the detection limit of 0.03 ng mL-1 and the relative standard deviation of < 2.5 %. In addition, this method permitted interference-free determination of OTA in real samples with recovery from 89.5 % to 102.8 %. This work provides a simple way to improve the selectivity of COFs for the determination of hazardous compounds in complex environments.

Excessive body weight in Developmental Coordination Disorder: A systematic review and meta-analysis.

Evidence on the link between Developmental Coordination Disorder (DCD) and obesity and overweight is mixed. Based on a pre-registered protocol (PROSPERO: CRD42023429432) we conducted the first systematic review/meta-analysis on the association between Developmental Coordination Disorder DCD and excessive weight. Web of Science, PubMed and an institutional database aggregator were searched until the 18th of December 2023. We assessed study quality using the Newcastle-Ottawa Scale and study heterogeneity using Q and I2 statistics. Data from 22 studies were combined, comprising 11330 individuals out of which 1861 had DCD. The main analysis showed a significant association between DCD and higher body weight (OR:1.87, 95% CI =1.43, 2.44). Meta-regression analyses indicated that the relationship was mediated by age, with stronger effects in studies with higher mean age (p 0.004). We conclude that DCD is associated with obesity and overweight, and this association increases with age. Our study could help to implement targeted prevention and intervention measures.

Textured insoles may improve some gross motor balance measures but not endurance measures in children with motor coordination issues. A randomised controlled feasibility trial.

BACKGROUND: Motor coordination concerns are estimated to affect 5%-6% of school-aged children. Motor coordination concerns have variable impact on children's lives, with gait and balance often affected. Textured insoles have demonstrated positive impact on balance and gait in adults with motor coordination disorders related to disease or the ageing process. The efficacy of textured insoles in children is unknown. Our primary aim was to identify the feasibility of conducting a randomised controlled trial involving children with motor control issues. The secondary aim was to identify the limited efficacy of textured insoles on gross motor assessment balance domains and endurance in children with movement difficulties. METHODS: An assessor-blinded, randomised feasibility study. We advertised for children between the ages of 5-12 years, with an existing diagnosis or developmental coordination disorder or gross motor skill levels assessed as 15th percentile or below on a norm-referenced, reliable and validated scale across two cities within Australia. We randomly allocated children to shoes only or shoes and textured insoles. We collected data across six feasibility domains; demand (recruitment), acceptability (via interview) implementation (adherence), practicality (via interview and adverse events), adaptation (via interview) and limited efficacy testing (6-min walk test and balance domain of Movement ABC-2 at baseline and 4 weeks). RESULTS: There were 15 children randomised into two groups (eight received shoes alone, seven received shoes and textured insoles). We experienced moderate demand, with 46 potential participants. The insoles were acceptable, however, some parents reported footwear fixture issues requiring modification. The 6-min walk test was described as problematic for children, despite all but one child completing. Social factors impacted adherence and footwear wear time in both groups. Families reported appointment locations and parking impacting practicality. Underpowered, non-significant small to moderate effect sizes were observed for different outcome measures. Improvement in balance measures favoured the shoe and insole group, while gait velocity increase favoured the shoe only group. CONCLUSION: Our research indicates that this trial design is feasible with modifications such as recruiting with a larger multi-disciplinary organisation, providing velcro shoe fixtures and using a shorter timed walk test. Furthermore, progressing to a larger well-powered randomised control trial is justified considering our preliminary, albeit underpowered, efficacy findings. TRIAL REGISTRATION: This trial was retrospectively registered with the Australian and New Zealand Clinical Trial Registration: ACTRN12624000160538.

Single Crystal to Single Crystal Transformation of Porous Materials based on Zinc Nodes and Mercaptobenzoic Acid.

Porous coordination polymers (PCPs) are an excellent class of porous crystalline materials with tunable properties and intriguing potential applications spanning multiple disciplines. In this work, we report the synthesis and characterization of a PCP (HI-103) based on 4,4'-dithiodibenzoic acid ligand and zinc nitrate with two DMF molecules residing in the porous network. The stability of the porous network was analyzed by heating the compound at 60.0 °C for two days, and the structural analysis revealed a new PCP (HI-104) was formed with one of the DMF molecules, indicating a single-crystal to single-crystal (SCSC) transformation. The solvent molecules were completely removed by extensive drying (HI-103-dry), and the integrity of the porous network was verified by powder X-ray diffraction (PXRD) and thermogravimetric analysis. The reversibility of SCSC transformation was confirmed by treating HI-103-dry with DMF molecules, resulting in HI-103 after five days. The adsorption studies of HI-103-dry with other solvents revealed that SCSC transformation was not observed for DMA and DEA, but some structural changes were observed in the presence of DMSO. The adsorption studies performed in the presence of an equimolar mixture of DMF, DMA, and DMA indicated that HI-103-dry could selectively adsorb DMF molecules from the analogous mixture.

Na[GeF5]·2HF: the first quarternary phase in the H-Na-Ge-F system.

The structure of cis- or trans-bridged [GeF5]- anionic chains have been investigated [Mallouk et al. (1984). Inorg. Chem. 23, 3160-3166] showing the first crystal structures of µ-F-bridged pentafluorogermanates. Herein, we report the second crystal structure of trans-pentafluorogermanate anions present in the crystal structure of sodium trans-pentafluorogermanate(IV) bis(hydrogen fluoride), Na[GeF5]·2HF. The crystal structure [orthorhombic Pca21, a = 12.3786 (3), b = 7.2189 (2), c = 11.4969 (3) Šand Z = 8] is built up from infinite chains of trans-linked [GeF6]2- octahedra, extending along the b axis and spanning a network of pentagonal bipyramidal distorted Na-centred polyhedra. These [NaF7] polyhedra are linked in a trans-edge fashion via hydrogen fluoride molecules, in analogy to already known sodium hydrogen fluorides and potassium hydrogen fluorides.

A novel one-dimensional thiocyanate-bridged cobalt(III) complex: synthesis, crystal structure characterization and Hirshfeld surface analysis.

A new one-dimensional thiocyanate-bridged cobalt(III) Schiff base complex, namely, catena-poly[[[4-bromo-2-((Z)-{[2-(thiophen-2-yl)ethyl]imino}methyl)phenolato-κ2N,O]cobalt(III)]-µ-thiocyanato-κ2N:S], [Co(SCN)(C13H11BrNOS)2]n or [Co(µ1,3-SCN)L2]n (1), where HL is 4-bromo-2-((Z)-{[2-(thiophene-2-yl)ethyl]imino}methyl)phenol, a bidentate Schiff base prepared from the condensation reaction of 5-bromosalicylaldehyde and 2-(thiophen-2-yl)ethylamine, has been synthesized by stirring Co(ClO4)2·6H2O, the Schiff base HL and ammonium thiocyanate (in a 1:2:1 molar ratio) in ethanol medium. The complex was characterized by FT-IR, electronic spectra and single-crystal X-ray diffraction (SC-XRD) studies. The SC-XRD data suggest that the compound crystallizes in the orthorhombic space group Pca21. The CoIII ion in 1 adopts a distorted octahedral geometry, the metal sites being six-coordinated by one thiocyanate N atom and one thiocyanate S atom in apical positions, and by two imine N atoms and two phenolate O atoms from two anionic L- ligands which form the basal plane. The thiocyanate ligand acts as a µ-1,3 bridge, joining neighbouring CoIII atoms and forming a uniform zigzag one-dimensional polymeric chain. The crystallographic data were also used in the Hirshfeld surface (HS) analysis, which aimed to investigate the nature and quantitative significance of any noncovalent intermolecular interactions inside the crystal lattice. The crystal void parameters have also been computed and show the molecules to be tightly packed.

Electrosynthesis of Transition Metal Coordinated Polymers for Active and Stable Oxygen Evolution.

Transition metal coordination polymers (TM-CP) are promising inexpensive and flexible electrocatalysts for oxygen evolution reaction in water electrolysis, while their facile synthesis and controllable regulation remain challenging. Here we report an anodic oxidation-electrodeposition strategy for the growth of TM-CP (TM = Fe, Co, Ni, Cr, Mn; CP = polyaniline, polypyrrole) films on a variety of metal substrates that act as both catalyst supports and metal ion sources. An exemplified bimetallic NiFe-polypyrrole (NiFe-PPy) features superior mechanical stability in friction and exhibits high activity with long-term durability in alkaline seawater (over 2000 h) and anion exchange membrane electrolyzer devices at current density of 500 mA cm-2. Spectroscopic and microscopic analysis unravels the configurations with atomically distributed metal sites induced by d-π conjugation, which transforms into a mosaic structure with NiFe (oxy)hydroxides embedded in PPy matrix during oxygen evolution. The superior catalytic performance is ascribed to the anchoring effect of PPy that inhibits the metal dissolution, the strong substrate-to-catalyst interaction that ensures good adhesion, and the Fe/Ni-N coordination that modulates the electronic structures to facilitate the deprotonation of *OOH intermediate. This work provides a general strategy and mechanistic insight into building robust inorganic/polymer composite electrodes for oxygen electrocatalysis.

Molecular Engineering of Hydrogen-Bonded Organic Framework for Enhanced Nitrate Electroreduction to Ammonia.

Electrocatalytic nitrate reduction is an efficient way to produce ammonia sustainably. Herein, we rationally designed a copper metalloporphyrin-based hydrogen-bonded organic framework (HOF-Cu) through molecular engineering strategies for electrochemical nitrate reduction. As a result, the state-of-the-art HOF-Cu catalyst exhibits high NH3 Faradaic efficiency of 93.8%, and the NH3 production rate achieves a superior activity of 0.65 mmol h-1 cm-2. The in situ electrochemical spectroscopic combined with density functional theory calculations reveals that the dispersed Cu promotes the adsorption of NO3- and the mechanism is followed by deoxidation of NO3- to *NO and accompanied by deep hydrogenation. The generated *H participates in the deep hydrogenation of intermediate with fast kinetics as revealed by operando electrochemical impedance spectroscopy, and the competing hydrogen evolution reaction is suppressed. This research provides a promising approach to the conversion of nitrate to ammonia, maintaining the nitrogen balance in the atmosphere.

Exploring the care coordination experiences of professionals and caregivers of youth with acquired brain injuries in rural areas.

PURPOSE: Acquired brain injuries (ABIs) can have devastating effects on children and their families. Families living in rural communities experience unique barriers to receiving and coordinating care for complex medical needs, but little research has examined those barriers for rural youth with ABIs. MATERIALS AND METHODS: This qualitative study explored the experiences of rural adults caring for children with ABIs through interviews with six caregivers, three school staff members, and three medical professionals who had treated at least one child with an ABI. RESULTS: Themes in their accounts include difficulty navigating complex situations, support from small communities, isolation and loneliness, the need for more professional education about ABI, and feelings of hope. Barriers to quality care coordination include navigating complex situations, access to transportation, and a lack of communication and education from healthcare agencies. Facilitators of rural care coordination include support from small communities and interagency communication. CONCLUSIONS: The results support the need for more comprehensive coordination among rural agencies involved in ABI care. Suggestions for care improvement include providing flexibility due to transportation barriers, capitalizing on the benefits of a small and caring community, and providing healthcare and education professionals with more education about ABI interventions.

Practitioners should implement tailored support systems that include initiatives to facilitate direct communication between rural medical agencies and schools.Expanding the role of care coordinators to bridge gaps across healthcare, education, and community services could enhance care coordination for children with acquired brain injuries in rural areas.Schools in rural areas should develop formal reintegration programs tailored to the needs of children with mild acquired brain injuries, leveraging existing sports protocols for non-sports-related injuries.Collaborative efforts between schools, medical teams, and community agencies can provide comprehensive education programs tailored to the rural context.The development of online options for follow-up appointments would be particularly beneficial in rural areas, where transportation barriers are more pronounced.

Coordination Engineering of Fe-centered Catalysts for Superior Li-S Battery Performance.

Iron-nitrogen functionalized graphene has emerged as a promising cathode host for rechargeable lithium-sulfur batteries (RLSBs) due to its affordability and enhanced battery performance. To optimize its catalytical efficiency, we propose a novel approach involving coordination engineering. Our investigation spans a plethora of catalysts with varied coordination environments, focusing on elements B, C, N and O. We revealed that Fe-C4 and Fe-B2C2-h are particularly effective for promoting Li2S oxidation, whereas Fe-N4 excels in catalyzing the sulfur reduction reaction (SRR). Importantly, our study identified specific descriptors - namely, the Integrated Crystal Orbital Hamilton Population (ICOHP) and the bond length between Fe and S in Li2S adsorbed state - as the most effective predictive descriptors for Li2S oxidation barriers. Meanwhile, Li2S adsorption energy emerges as a reliable descriptor for assessing the SRR barrier. These identified descriptors are expected to be instrumental in rapidly identifying promising cathode hosts across various metal-centered systems with diverse coordination environments. Our findings not only offer valuable insights into the role of coordination environment, but also present an effective path for rapidly identifying high performance catalysts for RLSBs, enabling the acceleration of advanced RLSBs development.

Axial O Atom-Modulated Fe(III)-N4 Sites for Enhanced Cascade Catalytic 1O2-Induced Tumor Therapy.

The rational construction of efficient hypoxia-tolerant nanocatalysts capable of generating singlet oxygen (1O2) without external stimuli is of great importance for tumor therapy. Herein, uniformly dispersed and favorable biosafety profile graphitic carbon nitride quantum dots immobilized with Fe-N4 moieties modulated by axial O atom (denoted as O-Fe-N4) are developed for converting H2O2 into 1O2 via Russell reaction, without introducing external energy. Notably, O-Fe-N4 performs two interconnected catalytic properties: glutathione oxidase-mimic activity to provide substrate for subsequent 1O2 generation, avoiding the blunting anticancer efficacy by glutathione. The O-Fe-N4 catalyst demonstrates a specific activity of 79.58 U mg-1 at pH 6.2, outperforming the most reported Fe-N4 catalysts. Density functional theory calculations demonstrate that the axial O atom can effectively modulate the relative position and electron affinity between Fe and N, lowering the activation energy, strengthening the selectivity, and thus facilitating the Russell-type reaction. The gratifying enzymatic activity stemming from the well-defined Fe-N/O structure can inhibit tumor proliferation by efficiently downregulating glutathione peroxidase 4 activity and inducing lipid peroxidation. Altogether, the O-Fe-N4 catalyst not only represents an efficient platform for self-cascaded catalysis to address the limitations of 1O2-involved cancer treatment but also provides a paradigm to enhance the performance of the Fe-N4 catalyst.

Synthesis, characterization and reactivity of a Mn(III)-hydroxido complex as a biomimetic model for lipoxygenase.

Manganese hydroxido (Mn-OH) complexes supported by a tripodal N,N',N″-[nitrilotris(ethane-2,1-diyl)]tris(P,P-diphenylphosphinic amido) ([poat]3-) ligand have been synthesized and characterized by spectroscopic techniques including UV-vis and electron paramagnetic resonance (EPR) spectroscopies. X-ray diffraction (XRD) methods were used to confirm the solid-state molecular structures of {Na2[MnIIpoat(OH)]}2 and {Na[MnIIIpoat(OH)]}2 as clusters that are linked by the electrostatic interactions between the sodium counterions and the oxygen atom of the ligated hydroxido unit and the phosphinic (P=O) amide groups of [poat]3-. Both clusters feature two independent monoanionic fragments in which each contains a trigonal bipyramidal Mn center that is comprised of three equatorial deprotonated amide nitrogen atoms, an apical tertiary amine, and an axial hydroxido ligand. XRD analyses of {Na[MnIIIpoat(OH)]}2 also showed an intramolecular hydrogen bonding interaction between the MnIII-OH unit and P=O group of [poat]3-. Crystalline {Na[MnIIIpoat(OH)]}2 remains as clusters with Na+---O interactions in solution and is unreactive toward external substrates. However, conductivity studies indicated that [MnIIIpoat(OH)]- generated in situ is monomeric and reactivity studies found that it is capable of cleaving C-H bonds, illustrating the importance of solution-phase speciation and its direct effect on chemical reactivity. Synopsis: Manganese-hydroxido complexes were synthesized to study the influence of H-bonds in the secondary coordination sphere and their effects on the oxidative cleavage of substrates containing C-H bonds.

Theoretical study of the effects of surface Cu coordination environment on CO2 hydrogenation to CH3OH.

The coordination environment of Cu (the coordination number and arrangement of surface atoms) plays an important role in CO2 hydrogenation to CH3OH. Compared with the extensive studies of the effects of coordination number, the comprehensive effects of coordination number and arrangement of surface atoms were seldom explored in literature. To unravel the effects of surface Cu coordination environment on CO2 hydrogenation to CH3OH, the adsorption and reaction behaviors of H2 and CO2 on Cu(111), (100), (110) and (211) with different coordination numbers and arrangement of surface Cu were systematically calculated by density functional theory (DFT) and kinetic Monte Carlo (kMC) simulation. It was found that the adsorption energies of intermediates in CO2 hydrogenation on Cu surfaces increase with the decrease of coordination number. When the Cu coordination numbers are similar, the charge density on the open surface derived from the different atom arrangement becomes larger and leads to stronger interaction with intermediates than that on the compact one. DFT calculation and kMC simulation indicate that methanol formation pathway follows CO2*→HCOO*→HCOOH*→H2COOH*→H2CO*→CH3O*→CH3OH* on four Cu facets; CO formation is via CO2 direct dissociation on Cu(111), (100) and (110) but COOH* dissociation on (211). The low-coordinated surface Cu with more openness on Cu(211) is the highly active site for CO2 hydrogenation to CH3OH with high turnover of frequency (3.71 × 10-4 s-1) and high selectivity (87.17 %) at 600 K, PCO2 = 7.5 atm and PH2 = 22.5 atm, which is much higher than those on Cu(111), (100) and (110). This work unravels the effects of coordination environment on CO2 hydrogenation at the molecular level and provides an important insight into the design and development of catalysts with high performance in CO2 hydrogenation to CH3OH.