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The significance of renewable energy sources underscores the importance of developing efficient battery technologies. Ethyl methyl carbonate (EMC), with its superior performance as an electrolyte, is widely utilized in lithium-ion batteries. However, the production of EMC through green transesterification of dimethyl carbonate (DMC) with ethanol encounters challenges due to low EMC selectivity and catalyst reusability issues. In this study, we present the initial instance of utilizing an imidazole-based ionic framework, [CPIL-M]n[PhO], which exhibits an interaction between its cationic backbone and basic anions. This interaction is specifically designed to catalyse the selective transformation of basic anions with suitable Lewis basicity in the production of EMC via transesterification. The introduction of N,N′-carbonyldiimidazole into the ionic framework allows for tunable modulation of Lewis basicity on an electronic level, enhancing catalytic activity without compromising selectivity. These innovative designs enable [CPIL-M]4[PhO] to exhibit remarkable performance, achieving 69.02% EMC yield and 90.19% selectivity, outperforming most reported catalysts. These findings could pave the way for the accelerated development of efficient catalysts for the sustainable production of EMC through transesterification methods in the future, thereby supporting the energy-efficient transition towards renewable energy sources. [ABSTRACT FROM AUTHOR]

Solid bases are valuable catalysts for industrial syntheses. However, controlling the basicity of these catalysts remains a challenge. Ga4B2O9, due to μ3-O within its structure, could behave as a special solid base catalyst exhibiting intrinsic Lewis basicity. In this work, a sol–gel method was proposed to obtain continuously adjustable acidity and basicity of the metal borate catalyst (AlxGa1−x)4B2O9. According to the results of NH3-TPD, CO2-TPD, and the systematic experimental design, Lewis basic sites originating from GaO5 groups in (AlxGa1−x)4B2O9 boost the Strecker reaction rather than the Lewis acid sites related to unsaturated Al. This work illustrates the possible application of bulk-type solid solutions with simultaneous Lewis acid and base sites for the first time. A reaction mechanism has also been proposed based on the catalytic reaction results. [ABSTRACT FROM AUTHOR]

The Lewis basicity of a μ3-oxo ligand for (μ3-O)[Rh(cod)]3(μ4-O)M (cod = 1,5-cyclooctadiene) complexes was controllable by metal species on the μ4-oxo ligand locating at the opposite site of the μ3-oxo ligand. Coordination of the μ3-oxo ligand of [(μ3-O){Rh(cod)}3(μ4-O){Au(PPh3)}][BF4] (1) to [Au(PPh3)]+ indicated sufficient Lewis basicity of the μ3-oxo ligand in 1 to form [{(Ph3P)Au}(μ3-O){Rh(cod)}3(μ4-O){Au(PPh3)}][BF4] (2). In contrast, the addition of Li+ to 1 induced elimination of the originally coordinated [Au(PPh3)]+ due to the weak Lewis basicity of the μ3-oxo ligand for (μ3-O){Rh(cod)}3(μ4-O)Li(THF)3, in which a pentanuclear species, [{(Ph3P)Au}(μ3-O){Rh(cod)}3(μ4-O){Li(THF)3}][BF4] (3), was assumed to be generated in situ before the dissociation of [Au(PPh3)]+. [ABSTRACT FROM AUTHOR]

Hexadentate poly-Lewis acids (PLA) based on the bowl-shaped tribenzotriquinacene (TBTQ) have been synthesised. The introduction of three n-propyl groups into the benzhydrylic positions of the TBTQ backbone has significantly increased the solubility of the subsequently derived compounds. Semi-flexible PLAs containing boron and aluminium were obtained by hydrometallation of the corresponding 2,3,6,7,10,11-hexaalkynyl-TBTQ. Other rigid hexadentate PLAs were synthesised by stannylation of the corresponding alkyne units with Me3SnNMe2 followed by tin-element exchange reactions. The Lewis acidity of these PLAs was investigated in host–guest experiments with pyridine. Further experiments with bidentate bases showed correlations between their flexibility, their Lewis basicity and the complexation behaviour towards the synthesised PLAs. Addition of bis((dimethylphosphino)methyl)dimethylsilane (BisPhos) to solutions of the rigid alkynyl PLAs led to the formation of 3 : 1 adducts. Single crystal X-ray diffraction was used to further elucidate the host–guest connectivtiy. In addition, a sixfold pnictogen-bonding donor was synthesised by tin-antimony exchange. [ABSTRACT FROM AUTHOR]

We demonstrate herein a reported syntheses pathway for form unsubstituted boron subnaphthalocyanines (BsubNcs) since their discovery in 1995 and to avoid random bay-position halogenation. This was achieved through the use of triphenyl borates as the macrocyclic templating reagent avoiding the formation of random bay-position halogenated BsubNc by-products. We also outline a method to screen boron templating reagents by computing their Lewis acidity using the fluoride ion affinity method as well as the screening of the macrocyclic precursor by determining its Lewis basicity using a boron trifluoride affinity scale of various organic macrocyclic precursors in order to balance these parameters to enable macrocycle formation. We find that a balancing of these parameters enabled multiple methods for the synthesis of unsubstituted BsubNc. For this study, we isolated the axially fluorinated and axially pentafluorophenoxylated BsubNcs and characterize their photophysical and electrochemical properties as there was no random bay-position substitutions. For this study, we also demonstrated as a 'part 2' the versatility in the synthetic methods developed through the synthesis of boron subphthalocyanines (BsubPcs), other BsubNcs and a hybrid materials of BsubPc + BsubNc called Bsub(Pc3-p + Ncp). We also explored an industrially relevant synthesis method of triphenyl borates and found it to be successful in the processes outlined herein providing a potential route to improving the sustainability of this class of triphenyl borate materials. [ABSTRACT FROM AUTHOR]

The interplay of two proximate gallium centres equips the bimetallic complex CyL2Ga2 (1, CyL2 = 1,2-trans-Cy[NC(Me)C(H)C(Me)N(Dip)]2, Dip = 2,6-i-Pr2C6H3) with increased Lewis basicity and higher reducing power compared to the monometallic gallanediyl LGa (2, L = HC[MeCN(Dip)]2) as evidenced by cross-over experiments. Quantum chemical calculations were employed to support the experimental findings. [ABSTRACT FROM AUTHOR]

The interplay of two proximate gallium centres equips the bimetallic complex CyL2Ga2 (1, CyL2 = 1,2-trans-Cy[NC(Me)C(H)C(Me)N(Dip)]2, Dip = 2,6-i-Pr2C6H3) with increased Lewis basicity and higher reducing power compared to the monometallic gallanediyl LGa (2, L = HC[MeCN(Dip)]2) as evidenced by cross-over experiments. Quantum chemical calculations were employed to support the experimental findings. [ABSTRACT FROM AUTHOR]

Two new SmII-azacryptates are reported that differ in steric hindrance and Lewis basicity of donor atoms. The sterically hindered complex has a smaller coordination number and a more negative electrochemical potential than the complex with less steric hindrance. [ABSTRACT FROM AUTHOR]

Halometallate ionic liquids provide new opportunities for industrial catalytic processes because of their unique blend of physical and chemical properties. Tunability underpins the success of ionic liquids because small structural changes can have drastic effects on either property. Catalysis can be optimised by adjusting structures to target properties such as Lewis basicity and acidity, but the structural changes have simultaneous impacts on physical properties. In this work, we provide a thorough, methodical, and reliable list of thermal parameters to help define temperature limits to prevent catalyst poisoning and limit the need to replace costly and environmentally demanding solvents. Mechanistic insights show that decomposition is particularly detrimental for halometallate ionic liquids, and life cycle analysis highlights that lower levels of organic cations are better for economic and environmental sustainability. [ABSTRACT FROM AUTHOR]

The standard potential of a lithium metal electrode versus the standard hydrogen electrode was calculated by constructing the thermodynamic cycle in a hypothetical electrochemical cell with a dual-phase electrolyte. It is demonstrated that the standard potential of the lithium metal electrode can fluctuate over 0.5 V in different organic solvents, and is correlated to the modified donor number by the entropy of fusion of the solvents. [ABSTRACT FROM AUTHOR]

The all-ceramic RuO2@La0.7Ca0.3CuO3 membrane cathode contributes to an ultra-high capacity of 21 518 mA h g−1 over 110 cycles in Li–O2 batteries. A simple infiltration technique is effective for obtaining a highly active supported RuO2 catalyst, and a solvent with a high donor number should be preferentially chosen because it contributes to a much higher capacity. [ABSTRACT FROM AUTHOR]

The dissolution of LiNO3 in carbonate electrolytes is achieved by introducing pyridine as a new carrier solvent owing to its higher Gutmann donor number than NO3−. The Li metal anode in LiNO3-containing carbonate electrolyte demonstrates a much enhanced reversibility due to the preferential reduction of LiNO3 and the formation of an inorganic-rich SEI. [ABSTRACT FROM AUTHOR]

To generate large single crystals of 3D covalent organic frameworks, the active use of ionic additives, which can greatly impact crystal size, is proposed. The crystal size ranking was found to be in accordance with the Hofmeister series and Gutmann donor number, providing a useful strategy to enhance crystal size and, consequently, generate COF-300 single crystals of >200 μm in size. [ABSTRACT FROM AUTHOR]

In this frontier article some peculiar characteristics of Zn(salen)-type Schiff-base complexes are reviewed. The paper is mainly focused on the most recent and relevant achievements on responsive supramolecular nanostructures and sensing properties, both of them related to the Lewis acidic character of the ZnII centre in these molecular species, providing an interpretation of these features. The sensing properties of Zn(salen)-type complexes mainly originate from optical spectroscopic changes associated with the formation of the adducts upon addition of a Lewis base (analyte), either by deaggregation of dimeric species or displacement of the solvent coordinated to the metal centre. In both cases the direct sensing is related either to the Lewis acidic character of the complex as well as to the Lewis basicity of the analyte. The formation of responsive nanostructures with fluorescent, and/or vapochromic, mechanochromic, and thermochromic characteristics is driven by non-mutual intermolecular Zn⋯O interactions, further stabilized by π–π stacking interactions and/or interdigitation of the alkyl side groups. The Lewis acidic character is not a prerogative of Zn(salen)-type complexes of tetradentate Schiff-bases. Many other classes of ZnII complexes can possess this property. A correct interpretation of their chemistry is certainly useful for further development of these classical coordination compounds as new molecular materials. [ABSTRACT FROM AUTHOR]

Quantum chemical calculations have been carried out on a series of skeletally modified cyclic alkyl amino silylenes (CAASis) and germylenes (CAAGes) to understand their ligand properties and reactivity towards the activation of a variety of small molecules. The installation of boron or silicon atoms into the ring framework of these silylenes/germylenes led to a dramatic increase in their σ-basicity while the incorporation of ylidic moieties resulted in a sharp reduction of their π-acidity although it did help in increasing the electron donation ability. The calculated values of energy barriers for the activation of H–H, N–H, C–H and Si–H bonds by many of the cyclic silylenes considered here are found to be comparable to those for experimentally evaluated systems, indicating the potential of these computationally designed molecules in small molecule activation and calling for synthetic efforts towards their isolation. Furthermore, activations employing CAAGes are found to be more demanding than those with CAASis which may be attributed to the significantly lower Lewis basicity of the former than the latter. [ABSTRACT FROM AUTHOR]

The physical dissolution of carbohydrates (cellulose, chitin, and starch), i.e., without the formation of covalent bonds requires the solvent to possess certain physicochemical properties. Concentrating on cellulose, the solvent should act both as a Lewis acid and a Lewis base, and disrupt the present hydrophobic interactions, as the biopolymer exhibits amphiphilic characteristics. The quantification of the relative importance of these physicochemical properties helps in predicting the solvent structures, which are expected to be efficient as cellulose solvents. Ionic liquids (ILs) are extensively used as carbohydrate solvents because they disrupt the intramolecular-, intermolecular-, and hydrophobic interactions within the biopolymer structure, leading to its dissolution. Solvatochromic substances (probes) are especially sensitive to one or more of the above-mentioned biopolymer–solvent interactions. Consequently, they are used to predict and rationalize the solvent efficiency. The solvent parameters (descriptors) most widely employed are empirical polarity, ET(probe), Lewis acidity (SA); Lewis basicity (SB), dipolarity (SD), and polarizability (SP); S refers to the solvent. We synthesized 18 ILs, including derivatives of imidazole, 1,8-diazabicyclo[5.4.0]undec-7-ene, and tetramethylguanidine; the corresponding anions are carboxylates, chloride and dimethylphosphate. We used solvatochromic probes to calculate the descriptors of IL–DMSO (at fixed DMSO mole fraction of 0.6; 40 °C), and correlated ET(probe) with the other descriptors. We also tested the correlations by using a molar volume of the IL (VM) instead of SD, and the Lorentz–Lorenz refractive index function f(n) of the IL–DMSO mixture instead of SP. The quality of the regression analysis increased noticeably when we limited the ILs correlated with those based on imidazole (13 ILs), and used (VM) and f(n). The regression coefficients showed that SA is the most important descriptor; the solvent empirical polarity is inversely dependent on VM. The value of f(n) shows the importance of hydrophobic interactions. By using different probes, we showed that the observed small contribution of SB reflects the steric crowding around the positive nitrogen atoms in some probes. The results obtained help in selecting ILs as solvents for cellulose and other carbohydrates, based on the expected strength of their interactions with the biopolymers. Therefore, using solvatochromism for solvent efficiency screening saves labor and cost. [ABSTRACT FROM AUTHOR]

Cationic halogen-bonding-donors with little or non-coordinating counter anions have attracted great attention as new Lewis acid type organocatalysts. However, these anions cannot function as nucleophilic activation sites due to their low Lewis basicity. In this study, 1,3,4-triaryl-5-iodotriazolium iodides have been developed as bifunctional catalysts for simultaneous activation of nucleophiles and electrophiles. Computational and experimental studies indicated that the nucleophilicity of the counter anions plays an important role in achieving high catalytic efficiency for the cyanosilylation of aldehydes. In addition, the first report on carbon dioxide fixation by XB-donors is described. [ABSTRACT FROM AUTHOR]

In the X-ray structures of the 1 : 1 adduct of [Ph3P＝N＝PPh3]2[PtCl4] with 1,4-diiodotetrafluorobenzene (1·FIB) and the salt [Ph3PCH2I]2[PtCl4] (2), the tetrachloroplatinate(II) anion behaves as a halogen bond (XB)-accepting tecton toward σ-hole-donating organohalogen species to form either C–I⋯Cl–PtCl2–Cl⋯I–C or C–I⋯Cl–PtCl3 moieties, respectively. All XB contacts are clearly observed on the Hirshfeld surfaces; in addition, intermolecular contacts are visualized using noncovalent interactions (NCI) analysis. The steric factor and the number of XB donor centers play important roles in the supramolecular organization of compounds 1·FIB and 2: the bifunctional FIB with two σ-hole donor centers forms an extended structure, including the bridging [PtCl4]2−, whereas the [Ph3PCH2I]+ cation with a σ-hole donor center in a sterically encumbered environment forms only one terminal XB with [PtCl4]2−. The results of DFT calculations followed by topological analysis of the electron density distribution within the framework of the QTAIM method at the ωB97XD/DZP-DKH level of theory reveal that the energies of the attractive intermolecular noncovalent interactions are 6.3–6.4 kcal mol−1 for compound 1·FIB and 2.6–2.9 kcal mol−1 for compound 2. [ABSTRACT FROM AUTHOR]

Potassium salt prepared AMO-MgxAl-LDH(K) (x = 2–5) have been studied as catalyst precursors for biodiesel synthesis. Calcined potassium salt prepared [AMO-Mg0.75Al0.25(OH)2](CO3)0.17K0.01 {AMO-Mg3Al-LDH(K)} with high surface area (366.1 m2 g−1) and Lewis basicity density (2.87 μmol m−2) catalyses the transesterification of sunflower oil with methanol to yield fatty acid methyl esters (FAMEs) after 300 minutes (99%), a much higher performance than conventional LDHs. [ABSTRACT FROM AUTHOR]

In this contribution, the synthesis and the unusual aggregation/deaggregation properties in solution of two dinuclear ZnII Schiff-base complexes of tetradentate Schiff-base units, having non-conjugated spacers between each molecular unit, are reported in comparison to the mononuclear model complex. Through detailed 1H NMR, DOSY NMR, optical absorption, fluorescence emission, and multivariate analysis of optical absorption data, emerge some interesting findings. In solution of non-coordinating solvents, these Lewis acidic species are characterized as monomers stabilized by formation of intramolecular aggregates, having distinct spectroscopic properties in comparison to intermolecular aggregates derived from the mononuclear model analogue. Instead, in coordinating solvents they exhibit a typical behaviour, with formation of stable adducts showing a strong fluorescence. Deaggregation studies using pyridine as reference Lewis base allowed establishing a larger thermodynamic stability of these intramolecular aggregates, in comparison to intermolecular aggregates, even larger than that of aggregates of conjugated multinuclear complexes. The combined analysis of spectroscopic data upon deaggregation with ditopic Lewis bases unambiguously demonstrated the formation of stable 1 : 1 adducts, with higher binding constants in comparison to those related to monotopic species. Therefore, the present Lewis acidic, dinuclear complexes behave as molecular tweezers of ditopic guests having a strong Lewis basicity. [ABSTRACT FROM AUTHOR]

Developing green, efficient, and low-cost catalysts for methylation of N–H by using CO2 as the C1 resource is highly desired yet remains a significant challenge. Herein, N-doped porous carbons (NPCs) were designed, synthesized, and proved to be an excellent metal-free catalyst for CO2-participated methylation conversion. NPCs were prepared via the pyrolysis of a mixture of tannic acid and urea. Both theoretical calculation and experiment demonstrate that the N species especially pyridinic N and pyrrolic N within NPCs can work as Lewis basic sites for attacking CO2 to weaken the C＝O bonds and lower the molecule conversion barrier, facilitating the subsequent methylation of N–H to produce, for example, N,N-dimethylaniline. Besides, the unique porous structure can enrich CO2 and accelerate mass transfer, synergistically promoting the conversion of CO2. The optimized NPC(1/5) catalyst, integrating the porous structure and strong Lewis basicity, exhibits excellent catalytic activity for CO2-based methylation reaction under mild conditions (1 bar CO2, 75 °C). Our work, for the first time, demonstrates the feasibility of using NPCs to catalyze the methylation of amino compounds to produce N,N-dimethylamine by exploiting CO2 as the C1 resource. [ABSTRACT FROM AUTHOR]

Developing green, efficient, and low-cost catalysts for methylation of N–H by using CO2 as the C1 resource is highly desired yet remains a significant challenge. Herein, N-doped porous carbons (NPCs) were designed, synthesized, and proved to be an excellent metal-free catalyst for CO2-participated methylation conversion. NPCs were prepared via the pyrolysis of a mixture of tannic acid and urea. Both theoretical calculation and experiment demonstrate that the N species especially pyridinic N and pyrrolic N within NPCs can work as Lewis basic sites for attacking CO2 to weaken the C＝O bonds and lower the molecule conversion barrier, facilitating the subsequent methylation of N–H to produce, for example, N,N-dimethylaniline. Besides, the unique porous structure can enrich CO2 and accelerate mass transfer, synergistically promoting the conversion of CO2. The optimized NPC(1/5) catalyst, integrating the porous structure and strong Lewis basicity, exhibits excellent catalytic activity for CO2-based methylation reaction under mild conditions (1 bar CO2, 75 °C). Our work, for the first time, demonstrates the feasibility of using NPCs to catalyze the methylation of amino compounds to produce N,N-dimethylamine by exploiting CO2 as the C1 resource. [ABSTRACT FROM AUTHOR]

The compounds EtOC(=O)CHNNPR3 (R = Ph 1, Cy 2, tBu 3) were prepared via the reactions of the diazomethane and a phosphine. In subsequent reactions with B(C6F5)3, the compounds 2 and 3 are shown to exhibit Lewis basicity at the carbonyl oxygen affording EtOC(=O(B(C6F5)3))CHNNPR3 (R = Cy 5, tBu 6). Reactions of 5 and 6 with water or phenol illustrated the Brønsted basicity at the nitrogen atom adjacent phosphorus, affording the compounds, [EtOC(=O)CHNNHPR3][HOB(C6F5)3] (R = Cy 7, tBu 8) and [EtOC(=O)CHNNHPR3][PhOB(C6F5)3] (R = Cy 9, tBu 10), respectively. The formulation of these products is confirmed via spectroscopic and crystallographic studies, and insight is garnered from computations. [ABSTRACT FROM AUTHOR]

Pillared-layer metal–organic frameworks show great promise for gas storage and separation because their pore size as well as functionality usually can be controlled and adjusted synergistically. By combining the common pyridine and carboxylate groups, we design herein a new 3D pillared-layer framework, [Co2(DBPT)(BPY)2(CO3)]n (SNNU-95). Dinuclear [Co2] motifs are connected by DBPT ligands to form a 2D layer, which is further bridged by BPY to obtain the 3D pillar-layered framework of SNNU-95. Remarkably, two un-coordinated pyridine groups of DBPT not only help stabilize the 2D layer through π…π stacking but also point into the 1D channels to create an ultramicroporous environment. Taking advantage of the ultramicroporosity and pyridine Lewis basic sites, SNNU-95 shows not only extra high CO2 over CH4 and C2 hydrocarbons over CH4 selectivity, but also remarkable C2H2/CO2, C2H2/C2H4, and C2H4/CO2 separation under ambient conditions. This synergistic effect resulting from functional groups and pore size provides a promising route to design porous materials for the highest possible gas uptake and separation performance. [ABSTRACT FROM AUTHOR]

A highly π-acidic dipyridinium-naphthalene diimide acceptor shows anion–π interactions with halides and PF6−. Lewis basicity and redox potential of the anion affect the chemistry, and photophysical and electrochemical properties, as well as both ionic and electrical conductivities. Our results provide insights into doping, degradation and ion transport mechanisms in organic n-type semiconductors. [ABSTRACT FROM AUTHOR]

A robust indium–organic framework (InOF-15) with open metal sites and Lewis basic sites has been successfully synthesized using a quinoline-based dicarboxylic acid. Moreover, it exhibits high IAST selective CO2 sorption from CO2/CH4 and CO2/N2 mixtures at 273 K, which has been attributed to the coexistence of OMSs and LBSs with strong synergistic effects. [ABSTRACT FROM AUTHOR]

Anions are ubiquitous species playing a primary role in chemistry, whose reactivity is essentially dominated by their Lewis basicity. However, no Lewis basicity data, in terms of Gibbs energy, are reported in the literature. We report here the first Lewis basicity of relevant monoanions through the determination of binding constants for the formation of stable 1 : 1 adducts, using a ZnII Schiff-base complex, 1, as a reference Lewis acid. Binding constants for equilibrium reactions were achieved through a nonlinear regression analysis of the binding isotherms from spectrophotometric titration data. The Lewis acidic complex 1 is a proper reference species because it forms stable adducts with both neutral and charged Lewis bases, thus allowing ranking their Lewis basicity. Binding constants indicate generally a strong Lewis basicity for all involved anions, rivalling or exceeding that of the stronger neutral bases, such as primary amines or pyridine. The cyanide anion results to be the strongest Lewis base, while the nitrate is the weaker base within the present anion series. Moreover, even the weaker base anions behave as stronger bases than the most common non-protogenic coordinating solvents. [ABSTRACT FROM AUTHOR]

The pronounced beneficial effect of a precise amount of protic additive in an enantioselective Cu-catalysed Diels–Alder reaction is reported. This reaction, which employs a cyclic alkylidene β-ketoester as a dienophile, represents one of the first examples of a transformation where these extremely versatile, though highly unstable reaction partners participate effectively in catalytic asymmetric cycloaddition with a functionalised diene. The cycloadduct was used as an intermediate towards the synthesis of magellanine-type Lycopodium alkaloids featuring a Stille cross-coupling of a highly congested enol triflate and a unique Meinwald rearrangement/cyclopropanation sequence. [ABSTRACT FROM AUTHOR]

The parent tris(pyrazolyl)phosphine and its 3,5-Me2, 3-Ph, and 3-t-Bu derivatives have been prepared by a simple procedure and show modest Lewis basicity of the phosphorus apex as was established by the magnitude of the 1JP,Se coupling constant of the phosphine selenides. Because of the chelating properties of both the N- and P-sites, neutral phosphorus-centered scorpion ligands allow coordination modes that are unavailable to the abundantly used anionic tris(pyrazolyl)borate scorpionates as we established for Cu(i)-complexation. The substituted P-scorpion ligands only allow for N-coordination, as the P-apex is presumably less accessible. Two X-ray crystal structures were obtained for the Cu-complex of tris(3,5-dimethylpyrazolyl)-phosphine with acetonitrile and triphenylphosphine in the fourth coordination site. The parent P-scorpion ligand can chelate with both its pyrazolyl groups and its P-apex with the product depending on the ratio in which it is mixed with the Cu(i) complex. Reacting two equivalents of the ligand with [Cu(MeCN)4][PF6] resulted in a complex in which Cu is coordinated to the three pyrazolyl groups of one ligand and to the P-apex of the other ligand as confirmed by an X-ray crystal structure determination and a DFT computational analysis. Reacting the ligand and the Cu(i) complex in an equimolar ratio resulted in a remarkable one-dimensional P-scorpion coordination polymer for which a single crystal X-ray structure could be determined. A detailed analysis of the structural features is presented. [ABSTRACT FROM AUTHOR]

An expanded pyridyl-decorated MOF-505 analogue[Cu2(L)(H2O)2]·Gx (H4L = 5,5′-(pyridine-2,5-diyl)diisophthalic acid, G = solvent molecule) has been solvothermally synthesized and reported. It exhibited rare hierarchical meso- and microporosity. With exposed unsaturated CuII sites and Lewis basic pyridyl sites, the material shows both large CO2-uptake capacity (123.4 cm3 g−1 at 273 K, 1 bar) and high selectivity for CO2 over N2 (55.7) at 273 K. Furthermore, for the first time the compound has been exploited for its heterogeneous catalytic performance toward the cyanosilylation reaction under solvent-free conditions. The compound can be recycled up to five times with only a minor loss of activity. [ABSTRACT FROM AUTHOR]

A new three-dimensional NbO-type porous metal–organic framework ZJNU-47 was synthesized via a solvothermal reaction of Cu(NO3)2·3H2O and a Lewis basic nitrogen donor site-rich tetracarboxylate, namely, 5,5′-(pyridazine-3,6-diyl)-diisophthalate, and the structure was characterized by single-crystal X-ray diffraction to be isostructural with NOTT-101. With the synergistic effect of open metal sites, Lewis basic sites and a suitable pore space, the MOF material ZJNU-47a after activation can take up a large amount of C2H2 and CO2. The gravimetric C2H2 uptake of 214 cm3 (STP) g−1 at room temperature and 1 atm is the highest among all reported MOFs to date, and the gravimetric CO2 uptake of 108 cm3 (STP) g−1 is also among the highest reported for MOFs. Compared to the isostructural MOF NOTT-101a, ZJNU-47a exhibits a significant increase in C2H2 and CO2 uptake and thus improved C2H2/CH4 and CO2/CH4 separations. Significantly, comprehensive DFT studies of C2H2 and CO2 adsorption have revealed that the open nitrogen donor sites are comparable and even superior to open metal sites regarding the adsorption sites. This work demonstrated that the simultaneous introduction of Lewis basic nitrogen donor sites and Lewis acidic metal sites into the framework is a promising approach to improve the gas sorption toward CO2 and C2H2 and thus to produce materials possessing enhanced C2H2/CH4 and CO2/CH4 separation performance. [ABSTRACT FROM AUTHOR]

Stirring Lewis-basic transition metal complexes with the salts M[BAr4Cl] (M = Ag, Tl; ArCl = 3,5-C6H3Cl2) resulted in the formation of diplatinum complexes [{(Cy3P)2Pt}2(μ-Ag)][BAr4Cl] (3) and [{(Cy3P)2Pt}2(μ-Tl)][BAr4Cl] (4) and the diiron compound [{(OC)3(Me3P)2Fe}2(μ-Ag)] (5) featuring bridging, unsupported metal cations. Their properties were investigated by multinuclear NMR spectroscopy, as well as X-ray diffraction and infrared measurements. [ABSTRACT FROM AUTHOR]

In this article, we focus on the important role of solvent donor and acceptor properties of ionic liquids in the elucidation of inorganic reaction mechanisms. For this purpose, mechanistic and structural studies on typical inorganic reactions, performed in ionic liquids, have been conducted. The presented systems range from simple complex-formation and ligand-substitution reactions to the activation of small molecules by catalytically active complexes. The data obtained for the reactions in ionic liquids are compared with those for the same reactions carried out in conventional solvents, and are discussed with respect to the donor and acceptor properties of the applied ionic liquids. The intention of this perspective is to gain more insight into the role of ILs as solvents and their interaction with metal ions and complexes in solution. [ABSTRACT FROM AUTHOR]

A new family of manganese(III) complexes of the type [Mn(L)Cl], where H2L is 1,4-bis(2-hydroxy-benzyl)-1,4-diazepane (H2(L1)), 1,4-bis(2-hydroxy-4-methylbenzyl)-1,4-diazepane (H2(L2)), 1,4-bis(2-hydroxy- 3,5-dimethylbenzyl)-1,4-diazepane (H2(L3)) and 1,4-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-1,4-diazepane (H2(L4)), has been isolated and studied as a catalyst for epoxidation reaction. Complexes 1-4 have been characterized using elemental analysis, electronic spectral and electrochemical methods and ESI-MS. The single crystal X-ray structures of 1 and 3 contain the MnN2O2Cl chromophore with a novel square pyramidal coordination geometry (τ: 1, 0.11; 3, 0.00). All the complexes possess a distorted square pyramidal coordination geometry in solution, as revealed by the characteristic bands observed in the electronic spectra. A time dependent density functional theory (TD-DFT) calculation has been performed to assist in the assignment of the electronic absorption spectral bands of the complexes. The Mn(III)/Mn(II) redox potentials (E1/2) of 1-4 fall within the narrow range of 0.279-0.320 V. The catalytic ability of the complexes towards olefin epoxidation has been investigated using PhIO as the oxygen source at room temperature under an N2 atmosphere. Addition of N-methylimidazole to the reaction mixture leads to an increase in the epoxide yield. A correlation between the Lewis acidity of the Mn(III) center as tuned by the substituents on the phenolate ligand, and the epoxide yield and product selectivity has been observed. The present complexes act as better chemoselective catalysts for epoxidation of cyclohexene and styrene rather than cyclooctene. [ABSTRACT FROM AUTHOR]