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Cu3[4-I-3,5-(CF3)2Pz]3 exhibits stronger supramolecular Cu3⋯halogen interactions vs. its 4-Br/4-Cl analogues, double- vs. single-capped; this relativistic enhancement yet results in quenched phosphorescence.

New fluorescent BOSCHIBAs for selective staining of the endoplasmic reticulum in HeLa and HUVE cells.

The silver bound, organometallic 18-electron iron-pentacarbonyl ligand fragment can be stabilized using tunable, tris(pyrazolyl)borates generating isolable heterobimetallic, Ag–Fe compounds.

Guest Editors Linda H. Doerrer and Rasika Dias introduce the spotlight collection: “Fluorinated ligands and their effects on physical properties and chemical reactivity”.

Purification of C2 H4 from an C2 H4 /C2 H6 mixture is one of the most challenging separation processes, which is achieved mainly through energy-intensive, cryogenic distillation in industry. Sustainable, non-distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF3 )2 Bp]Cu}3 has features very desirable in an olefin-paraffin separation material. It binds ethylene exclusively over ethane generating [(CF3 )2 Bp]Cu(C2 H4 ). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C2 H4 /C2 H6 gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In-situ PXRD provides a "live" picture of the reversible conversion between [(CF3 )2 Bp]Cu(C2 H4 ) and the ethylene-free sorbent in the solid-state, driven by the presence or removal of C2 H4 . Molecular structures of trinuclear {[(CF3 )2 Bp]Cu}3 and mononuclear [(CF3 )2 Bp]Cu(C2 H4 ) are also presented.

Polyfluorinated, electron-withdrawing, and sterically demanding supporting ligands are of significant value in chemistry. Here we report the assembly and use of a bis(pyrazolyl)borate, [Ph2B(3-(SF5)Pz)2]− that combines all such features, and involves underutilized pentafluorosulfanyl substituents. The ethylene and carbonyl chemistry of copper(i) supported by [Ph2B(3-(SF5)Pz)2]−, a comparison to the trifluoromethylated counterparts involving [Ph2B(3-(CF3)Pz)2]−, as well as copper catalyzed cyclopropanation of styrene with ethyl diazoacetate and CF3CHN2 are presented. The results from cyclopropanation show that SF5 groups dramatically improved the yields and stereoselectivity compared to the CF3., Copper–ethylene and carbonyl complexes of the newly developed [Ph2B(3-(SF5)Pz)2]− enable the study of ligand steric and electronic effects caused by the –SF5 group (dubbed “super CF3”), and a comparison to the –CF3 bearing analogs.

Propylene is a crucial building block to produce many industrial-scale chemicals including polypropylene. The separation of propylene from propane to reach the high-purity levels needed for downstream applications is a difficult task due to the close similarities in their physical properties. The olefin/paraffin separation including that involving propylene mainly relies on highly energy-intensive distillation processes and accounts for nearly 0.3% of the global energy consumption. The utility of a copper complex supported by a fluorinated bis(pyrazolyl)borate is demonstrated to accomplish the separation of propylene from propane repeatedly, under mild conditions with high selectivity. Complete characterization of a rare, copper(I) propylene complex is also reported including the molecular structure.

The π-complexes of cationic coinage metal ions (Cu(I), Ag(I), Au(I)) provide useful experimental support for understanding fundamental characteristics of bonding and

Syntheses of the copper and gold complexes [Cu{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5‐(CF3)2C6H3}3] containing the homoleptic carbonyl cations [M{Fe(CO)5}2]+ (M=Cu, Au) are reported. Structural data of the rare, trimetallic Cu2Fe, Ag2Fe and Au2Fe complexes [Cu{Fe(CO)5}2][SbF6], [Ag{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5‐(CF3)2C6H3}3] are also given. The silver and gold cations [M{Fe(CO)5}2]+ (M=Ag, Au) possess a nearly linear Fe‐M‐Fe’ moiety but the Fe‐Cu‐Fe’ in [Cu{Fe(CO)5}2][SbF6] exhibits a significant bending angle of 147° due to the strong interaction with the [SbF6]− anion. The Fe(CO)5 ligands adopt a distorted square‐pyramidal geometry in the cations [M{Fe(CO)5}2]+, with the basal CO groups inclined towards M. The geometry optimization with DFT methods of the cations [M{Fe(CO)5}2]+ (M=Cu, Ag, Au) gives equilibrium structures with linear Fe‐M‐Fe’ fragments and D 2 symmetry for the copper and silver cations and D 4d symmetry for the gold cation. There is nearly free rotation of the Fe(CO)5 ligands around the Fe‐M‐Fe’ axis. The calculated bond dissociation energies for the loss of both Fe(CO)5 ligands from the cations [M{Fe(CO)5}2]+ show the order M=Au (D e=137.2 kcal mol−1)>Cu (D e=109.0 kcal mol−1)>Ag (D e=92.4 kcal mol−1). The QTAIM analysis shows bond paths and bond critical points for the M−Fe linkage but not between M and the CO ligands. The EDA‐NOCV calculations suggest that the [Fe(CO)5]→M+←[Fe(CO)5] donation is significantly stronger than the [Fe(CO)5]←M+→[Fe(CO)5] backdonation. Inspection of the pairwise orbital interactions identifies four contributions for the charge donation of the Fe(CO)5 ligands into the vacant (n)s and (n)p AOs of M+ and five components for the backdonation from the occupied (n‐1)d AOs of M+ into vacant ligand orbitals., Donation of an electron pair from the HOMO of [Fe(CO)5]2 to the 4s LUMO of Cu+ giving the (+,+) component of the Fe‐Cu‐Fe σ bond in [Cu{Fe(CO)5}2]+. The associated charge flow with the direction red→blue is given by the deformation density.

Ethylene complexes of gold(i) have been stabilized by electron-rich, κ2-bound tris(pyrazolyl)borate ligands. Large up-field shifts of olefinic carbon NMR resonances and relatively long C[double bond, length as m-dash]C distances of gold bound ethylene are indicative of significant Au(i) → ethylene π-backbonding relative to the analog supported by a weakly donating ligand, consistent with the computational data.

In the present work, we report the green synthesis of a Shiff base [N-(2-hydroxy-1-naphthylidene)-L-phenylalanine (1)] derived from an α-amino acid through an ultrasound-assisted synthesis method with excellent chemical yield in a short period of time. In the crystal framework, we found that compound 1 goes through a racemization process and remarkably a preferential intermolecular interaction between amino acid molecules with the same configuration was observed, i.e., a homo enantiomeric preference (HEP). This could indicate that an enantiomeric recognition could be observed in racemic mixtures of compounds that are derived from α-amino acids. Besides, a conformational study of 1 and a polymorph previously obtained in solid state for the same molecule was extensively discussed by the Hirshfeld surface, Finger plots, and DFT calculations.

We report the synthesis, characterization and computational analysis of coinage metal-ether complexes supported by N-heterocyclic carbenes (NHC), SIPr and Et2CAAC. The related water adducts are also included. The [(NHC)M]+(M = Cu, Ag, Au) species show the noteworthy ability to bind Et2O and H2O. This interaction towards Et2O and H2O is partly ascribed to a σ-hole bonding with an almost linear disposition, taking advantage of the enhanced σ-hole potential evaluated for such [(NHC)M]+ species. This enhanced ability is larger than those found for non-covalent interactions involving main group species.

Copper and silver play important roles in acetylene transformations but isolable molecules with acetylene bonded to Cu(i) and Ag(i) ions are scarce. This report describes the stabilization of π-acetylene complexes of such metal ions supported by fluorinated and non-fluorinated, pyrazole-based chelators. These Cu(i) and Ag(i) complexes were formed readily in solutions under an atmosphere of excess acetylene and the appropriate ligand supported metal precursor, and could be isolated as crystalline solids, enabling complete characterization using multiple tools including X-ray crystallography. Molecules that display κ

Treatment of bis(pyrazolyl)borate ligand supported [(CF3)2Bp]Cu(NCMe) with 1,2,3-trisubstituted cyclopropenes produced thermally stable copper(I) η2-cyclopropene complexes amenable to detailed solu...

The synthesis, isolation and crystal structures of nickel(II) carbonyl, aceto­nitrile and ammonia complexes supported by a dianionic, pyridine dipyrrolide pincer ligand [pyrr2py]2−, namely, carbonyl[2,2′-(pyridine-2,6-di­yl)bis­(3,5-di-p-tolyl­pyrrolido-κN)]­nickel(II), [Ni(C41H33N3)(CO)], ammine[2,2′-(pyridine-2,6-di­yl)bis­(3,5-di-p-tolyl­pyrrolido-κN)]nickel(II), [Ni(C41H33N3)(NH3)], and (aceto­nitrile-κN)[2,2′-(pyridine-2,6-di­yl)bis­(3,5-di-p-tolyl­pyrrolido-κN)]nickel(II), [Ni(C41H33N3)(CH3CN)], as well as the free ligand 2,6-bis­(3,5-di-p-tolyl­pyrrol-2-yl)pyridine, C41H35N3 or [pyrr2py]H2 are reported., The synthesis, isolation and crystal structures of nickel(II) carbonyl, aceto­nitrile and ammonia complexes supported by a dianionic, pyridine dipyrrolide pincer ligand [pyrr2py]2−, namely, carbonyl[2,2′-(pyridine-2,6-di­yl)bis­(3,5-di-p-tolyl­pyrrolido-κN)]­nickel(II), [Ni(C41H33N3)(CO)], ammine[2,2′-(pyridine-2,6-di­yl)bis­(3,5-di-p-tolyl­pyrrolido-κN)]nickel(II), [Ni(C41H33N3)(NH3)], and (aceto­nitrile-κN)[2,2′-(pyridine-2,6-di­yl)bis­(3,5-di-p-tolyl­pyrrolido-κN)]nickel(II), [Ni(C41H33N3)(CH3CN)], as well as the free ligand 2,6-bis­(3,5-di-p-tolyl­pyrrol-2-yl)pyridine, C41H35N3 or [pyrr2py]H2 are reported. The nickel complexes are four-coordinate and adopt a square-planar geometry. The CO stretch of the nickel-bound carbon monoxide ligand of [pyrr2py]Ni(CO) has been observed at 2101 cm−1. The ammonia and aceto­nitrile complexes, [pyrr2py]Ni(NH3) and [pyrr2py]Ni(NCMe) feature all-nitro­gen coordination spheres around nickel consisting of different N-donor ligand types.

Purifying alkenes from alkanes requires cryogenic distillation. This consumes energy equivalent to countries of ca. 5 million people. Replacing distillation with adsorption processes would significantly increase energy efficiency. Trade-offs between kinetics, selectivity, capacity, and heat of adsorption have prevented production of an optimal adsorbent. We report adsorbents that overcome these trade-offs. [Cu-Br]3 and [Cu-H]3 are air-stable trinuclear complexes that undergo reversible solid-state inter-molecular rearrangements to produce dinuclear [Cu-Br⋅(alkene)]2 and [Cu-H⋅(alkene)]2 . The reversible solid-state rearrangement, confirmed in situ using powder X-ray diffraction, allows adsorbent design trade-offs to be overcome, coupling low heat of adsorption (-10 to -17 kJ mol-1 alkene ), high alkene:alkane selectivity (47; 29), and uptake capacity (>2.5 molalkene mol-1 Cu3 ). Most remarkably, [Cu-H]3 displays fast uptake and regenerates capacity within 10 minutes.

Background: In this work, various carbon nanotubes (MWCNTs) were synthetized by the spray pyrolysis method. Resulting nanoforest-like and bamboo-like carbon nanotubes, as well as Yjunctions of carbon nanotubes, possess different shapes and morphology, depending on the kind of carbon source used and on the number of iron particles on the furnace tube surface, which derives from various concentrations of ferrocene catalyst. Methods: We used the spray pyrolysis method, using different carbon sources (n-pentane, n-hexane, nheptane, and acrylonitrile) as precursors and two different concentrations of ferrocene as a catalyst. Reactions of hydrocarbon decomposition were carried out at 800oC. The solution (hydrocarbon and catalyst) was introduced with a syringe, with a flow of 1 mL/min and the synthesis time of 20 min. Argon was used as carrier gas (1000 L/min). Preheater and oven temperatures were selected 180°C and 800°C, respectively, for each carbon source. The solution passed into a quartz tube placed in an oven. Results: According to the studies of carbon nanostructures, obtained from different precursors, it can be proposed that the structures synthesized from n-pentane, n-hexane and n-heptane are formed by the root growth method. The growth mechanism of MWCNTs was studied, confirming that the root growth formation of products takes place, whose parameters also depend on furnace temperature and gas flow rate. Dependence of interlayer distance (0.34-0.50 nm) in the formed MWCNTs on precursors and reaction conditions is also elucidated. The formation of carbon nanotubes does not merely depend on carbon precursors but also has strong correlations with such growth conditions as different catalyst concentrations, furnace temperature and gas flow rate. Such parameters as the amount of catalyst and synthesis time are also needed to be considered, since they are important to find minor values of these parameters in the synthesis of forest-like carbon nanotubes and other structures such as bamboo-like carbon nanotubes and Y-junctions in carbon nanotubes. Conclusions: As a result of the evaluation of interlayer distance in CNTs formed from different carbon sources, a standard value of interlayer distance normally for CNTs is 0.34 nm and for pentane A (0.5 wt.%), hexane B (1 wt.%), toluene A (0.5 wt.%) the range is from 0.33 to 0.35 nm. In case of pentane and acrylonitrile, under an increase of the catalyst concentration, an increase of the value of interlayer distance takes place from 0.35 and 0.4 to 0.4 and 0.5 nm, respectively, but for hexane, heptane and cyclohexane, an increase of the catalyst concentration maintains the same interlayer distance. This involves the use of lower quantities of raw materials and, therefore less cost for obtaining these materials.

The chemistry of trinuclear silver(I) pyrazolates with aromatic, bidentate N-heterocycles, 1,10-phenanthroline, 4,6-dimethylpyrimidine, 4,7-phenanthroline, benzo[c]cinnoline, and 4-(2-pyridyl)pyrimidine are presented. Results presented here show the effects of the donor nitrogen lone-pair orientations of the N-heterocycles on the product structures. The chelating ligand, 1,10-phenanthroline with {[3,5-(CF3)2Pz]Ag}3, {[4-Cl-3,5-(CF3)2Pz]Ag}3 and {[4-Br-3,5-(CF3)2Pz]Ag}3 produced tetranuclear species, that exhibited blue luminescence under UV light. 4,6-dimethylpyrimidine and 4,7-phenanthroline that have nitrogen lone pairs in a non-chelating arrangement produced polymeric, mixed ligand silver pyrazolate complexes when treated with {[3,5-(CF3)2Pz]Ag}3. The reaction of {[3,5-(CF3)2Pz]Ag}3 with benzo[c]cinnoline did not lead to the breakup of the precursor Ag3N6 core, but resulted in a trinuclear silver complex with two- and three-coordinate silver centers. The reaction between 4-(2-pyridyl)pyrimidine and {[3,5-(CF3)2Pz]Ag}3 generated a coordination polymer featuring saddle-shaped {[3,5-(CF3)2Pz]Ag}4 units. Most of these complexes show intermolecular π-stacking and argentophilic contacts. The fluorinated pyrazolate serves as a bridging ligand in all the silver complexes.

Copper(I) and silver(I) pyrazolate complexes {[3,5-(3,5-(CF3)2Ph)2Pz]Cu}3 and {[3,5-(3,5-(CF3)2Ph)2Pz]Ag}3 have been synthesized using the fluorinated 3,5-(diaryl)pyrazole 3,5-(3,5-(CF3)2Ph)2PzH and copper(I) oxide and silver(I) oxide, respectively. The gold(I) analog was obtained from a reaction between Au(THT)Cl and [3,5-(3,5-(CF3)2Ph)2Pz]H/NaH. The X-ray crystal structures show that the coinage metal complexes {[3,5-(3,5-(CF3)2Ph)2Pz]M}3 (M = Cu, Ag, Au) are trinuclear in the solid state. They feature distorted nine-membered M3N6 metallacyclic cores. The M–N distances follow Cu < Au < Ag, which is the trend expected from covalent radii of the corresponding coinage metal ions. The 3,5-(3,5-(CF3)2Ph)2PzH forms hydrogen bonded trimers in the solid state that are further organized by π-stacking between aryl rings. Solid samples of {[3,5-(3,5-(CF3)2Ph)2Pz]M}3 display blue photoluminescence. The copper complex {[3,5-(3,5-(CF3)2Ph)2Pz]Cu}3 is an excellent catalyst for mediating azide–alkyne cycloaddition chemistry.

The copper(I), silver(I), and gold(I) metals bind π-ligands by σ-bonding and π-back bonding interactions. These interactions were investigated using bidentate ancillary ligands with electron donating and withdrawing substituents. The π-ligands span from ethylene to larger terminal and internal alkenes and alkynes. Results of X-ray crystallography, NMR, and IR spectroscopy and gas phase experiments show that the binding energies increase in the order AgCuAu and the binding energies are slightly higher for alkynes than for alkenes. Modulation of the electron density at the metal using substituents on the ancillary ligands shows that the π-back bonding interaction plays a dominant role for the binding in the copper and gold complexes.

A series of DOSY experiments have been carried out to determine the solution stoichiometry of silver(I) 3,5-bis (trifluoromethyl)pyrazolate species. This compound exists as a trimer in the solid state (n = 3) but in solutions of chlorinated solvents, the DOSY data suggest the presence of a mixture of solvent stabilized monomer (n = 1) and dimer (n = 2) in equilibrium. Different approximations have been used including the Stokes-Einstein and the Stokes-Einstein-Gierer-Wirtz equations. Some methodological problems are discussed.

This paper provides a 4th manifestation of a new tradition by which the editors of Comments on Inorganic Chemistry wish to lead by example, whereby we start publishing original research content that, nonetheless, preserves the Journal’s identity as a niche for critical discussion of contemporary literature in inorganic chemistry. (For the 1st, 2nd and 3rd manifestations, see: a) Otten, B. M.; Melancon, K. M.; Omary, M. A. “All That Glitters is Not Gold: A Computational Study of Covalent vs Metallophilic Bonding in Bimetallic Complexes of d10 Metal Centers – A Tribute to Al Cotton on the 10th Anniversary of His Passing,” Comments Inorg. Chem. 2018, 38, 1–35; b) Yaseen, W. K.; Sanders, S. F.; Almotawa, R. M.; Otten, B. M.; Bhat, S.; Alamo, D. C.; Marpu, S. B.; Golden, T. D.; Omary, M. A. “Are Metal Complexes “Organic”, “Inorganic”, “Organometallic”, or “Metal-Organic” Materials? A Case Study for the Use of Trinuclear Coinage Metal Complexes as “Metal-Organic Coatings” for Corrosion Suppression on Aluminum Substrates”, Comments Inorg. Chem. 2019, 39, 1–26; and c) Smith, J. B.; Otten, B. M.; Derry, P. J.; Browning, C.; Bodenstedt, K. W.; Sandridge, J. H.; Satumtira, N. T.; Zilaie, M.; Payne, J.; Nuti, R.; Omary, M. A.; Smucker, B. W. “Luminescent, Redox-Active (Dithiolato)Bis(Imine)Platinum(II) Divergent Complexes with Exchangeable Imine Ligands: An Experimental/Computational Study versus Their (Diimine)(Dithiolato)Platinum(II) Convergent Congeners”, Comments Inorg. Chem. 2019, 39, 188–215.) Herein, the dinuclear complexes {Cu[3,5-(CF3)2Pz](µ-dppm)}2 and {Cu[3,5-(CF3)2Pz](µ-dppm)}2•3THF were studied structurally, spectroscopically and via density functional theory (DFT). They were synthesized by reacting bis(diphenylphosphino)methane (dppm) with the cyclic trinuclear complex {μ-[3,5-(CF3)2Pz]Cu}3 to effect nuclearity reduction. Two forms of crystalline solids, {Cu[3,5-(CF3)2Pz](µ-dppm)}2 and {Cu[3,5-(CF3)2Pz](µ-dppm)}2•3THF have been obtained using different recrystallization conditions. The {Cu[3,5-(CF3)2Pz](µ-dppm)}2 complex was found through DFT computations to undergo a distortion from a Y-shaped coordination sphere in the S0 ground state toward a T-shape in the T1 photoexcited, lowest-lying, phosphorescent state. The distortion also causes the copper-copper bond length to contract and form an excimer bond (dCu-Cu = 2.577 Å). Experimentally, the presence of THF in the crystal was found to cause a blue shift, effecting a change in emission color from teal to blue to the naked eye, with a near-unity quantum yields (93%), rendering the latter solid suitable for inorganic LED applications but not OLEDs, as thin films exhibit a reduced quantum yield. Crystallographic evidence suggests that THF leads to a more compact lattice that makes the complexes more rigid and thus hinder the excited state distortions vs unsolvated crystals. Greater distortion leads to a lower energy radiative emission and thus a red shift in the emission color. Films were also studied and found to undergo further red shifting as a result of less rigidity in the media and more surface molecules susceptible to distortion, hence manifesting the luminescence rigidochromism optical phenomenon in the solid state as opposed to the traditional manifestation in frozen vs fluid solution. Photobleaching was studied in both the film and powder to assess photostability, which was superior in neat vs doped solids, which is also favorable for LED applications.

Organic azide complexes of copper(I) and silver(I), [(SIPr)CuN(1-Ad)NN][SbF6], [(SIPr)CuN(2-Ad)NN][SbF6], [(SIPr)CuN(Cy)NN][SbF6], and [(SIPr)AgN(1-Ad)NN][SbF6] have been synthesized by using Ag[Sb...

Trinuclear {μ-[3,5-(CF3)2Pz]Cu}3 reacts with acetylene to produce the 2 : 1 copper(I) acetylene complex, Cu4(μ-[3,5-(CF3)2Pz])4(μ-HCCH)2. Related Cu4(μ-[4-Br-3,5-(CF3)2Pz])4(μ-HCCH)2 and Cu4(μ-[4-Cl-3,5-(CF3)2Pz])4(μ-HCCH)2 have also been isolated using the corresponding copper(I) pyrazolate and acetylene. The 1 : 1 adducts Cu2(μ-[3,5-(CF3)2Pz])2(HCCH)2 and Cu2(μ-[4-Br-3,5-(CF3)2Pz])2(HCCH)2 are significantly less stable to the acetylene loss and can be observed in solution at low temperatures under excess acetylene. The X-ray crystal structures of 2 : 1 and 1 : 1 complexes, Cu4(μ-[3,5-(CF3)2Pz])4(μ-HCCH)2 and Cu2(μ-[4-Br-3,5-(CF3)2Pz])2(HCCH)2 are reported. Raman data show a reduction in CC stretching frequency by about ∼340 and ∼163 cm−1 in the 2 : 1 and 1 : 1 Cu(I)/acetylene complexes, respectively, from that of the free acetylene. Copper(I) pyrazolate complexes of the terminal alkynes, phenylacetylene, 1,8-nonadiyne, and 1,7-octadiyne are also reported. They form adducts involving one copper atom on each alkyne moiety. The {μ-[3,5-(CF3)2Pz]Cu}3 is also a very versatile and competent catalyst for alkyne transformations as evident from its ability to catalyze the alkyne C(sp)–H bond carboxylation chemistry with CO2, azide–alkyne cycloadditions leading to 1,2,3-triazoles including the use of acetylene itself as a substrate, and thiol addition to phenylacetylene affording vinyl sulfides.

Syntheses of neutral and anionic, di- and tetra-nuclear copper carbon monoxide complexes using binary copper(i) pyrazolate precursors are reported. The reaction of {[3,5-(CF3)2Pz]Cu}3 (2), {[4-Cl-3,5-(CF3)2Pz]Cu}3 (3) or {[3,4,5-(CF3)3Pz]Cu}3 (4) with CO in CH2Cl2 led to copper carbonyl complexes. They however, lose CO quite easily if not kept under a CO atmosphere. Compounds {[3,5-(CF3)2Pz]Cu(CO)}2 (5) and {[3,4,5-(CF3)3Pz]Cu(CO)}2 (7) were characterized by X-ray crystallography. They are dinuclear species with a Cu2N4 core. The reaction of {[3,5-(CF3)2Pz]Cu}3 with CO in the presence of [NEt4]Br or [NEt4][3,5-(CF3)2Pz] affords relatively more stable [NEt4][{[3,5-(CF3)2Pz]Cu(CO)}4(μ4-Br)] (8) and [NEt4]{[3,5-(CF3)2Pz]3Cu2(CO)2} (9). The related [NEt4][{[4-Cl-3,5-(CF3)2Pz]Cu(CO)}4(μ4-Br)] (10) and [NEt4][{[4-Cl-3,5-(CF3)2Pz]Cu(CO)}4(μ4-Cl)] (11) can be synthesized using {[4-Cl-3,5-(CF3)2Pz]Cu}3, CO and [NEt4]Br or [NEt4]Cl. The X-ray structures show that 8, 10 and 11 are tetranuclear species with terminal Cu-CO groups and quadruply bridging Cl- and Br- ions. Compound 9 features an anionic cage of nearly D3h symmetry formed by three bridging [3,5-(CF3)2Pz]- ions and two terminal Cu-CO moieties. Theoretical calculations show that bonding in these 16- and 18-electron copper complexes follows Dewar-Chatt-Duncanson (DCD) model, where the CO stretching frequencies correlate well to the orbital interaction energy ΔEorb. The major Cu-CO interaction however is electrostatic in nature. Further theoretical exploration of the role of the substituent at pyrazolyl ring 4-position between -H, -Cl, and -CF3, shows a slight decrease in covalent character of the Cu-CO interaction and diminished π-back bonding as pyrazolate groups become more weakly donating with added electron withdrawing substituents.

Although unsaturated organotrifluoroborates are common synthons in metal-organic chemistry, their transition metal complexes have received little attention. [CH2(3,5-(CH3)2Pz)2]Cu(CH2[double bond, length as m-dash]CHBF3), (SIPr)Cu(MeCN)(CH2[double bond, length as m-dash]CHBF3) and [CH2(3,5-(CH3)2Pz)2]Ag(CH2[double bond, length as m-dash]CHBF3) represent rare, isolable molecules featuring a vinyltrifluoroborate ligand on coinage metals. The X-ray crystal structures show the presence of three-coordinate metal sites in these complexes. The vinyltrifluoroborate group binds asymmetrically to the metal site in [CH2(3,5-(CH3)2Pz)2]M(CH2[double bond, length as m-dash]CHBF3) (M = Cu, Ag) with relatively closer M-C(H)2 distances. The computed structures of [CH2(3,5-(CH3)2Pz)2]M(CH2[double bond, length as m-dash]CHBF3) and M(CH2[double bond, length as m-dash]CHBF3), however, have shorter M-C(H)BF3 distances than M-C(H)2. These molecules feature various inter- or intra-molecular contacts involving fluorine of the BF3 group, possibly affecting these M-C distances. The binding energies of [CH2[double bond, length as m-dash]CHBF3]- to Cu+, Ag+ and Au+ have been calculated at the wB97XD/def2-TZVP level of theory, in the presence and absence of the supporting ligand CH2(3,5-(CH3)2Pz)2. The calculation shows that Au+ has the strongest binding to the [CH2[double bond, length as m-dash]CHBF3]- ligand, followed by Cu+ and Ag+, irrespective of the presence of the supporting ligand. However, in all three metals, the supporting ligand weakens the binding of olefin to the metal. The same trends were also found from the analysis of the σ-donation and π-backbonding interactions between the metal fragment and the π and π* orbitals of [CH2[double bond, length as m-dash]CHBF3]-.

We report the synthesis, characterization and computational analysis of coinage metal-ether complexes supported by N-heterocyclic carbenes (NHC), SIPr and Et2CAAC. The related water adducts are also included. The [(NHC)M]+(M = Cu, Ag, Au) species show the noteworthy ability to bind Et2O and H2O. This interaction towards Et2O and H2O is partly ascribed to a σ-hole bonding with an almost linear disposition, taking advantage of the enhanced σ-hole potential evaluated for such [(NHC)M]+ species. This enhanced ability is larger than those found for non-covalent interactions involving main group species.

A series of DOSY experiments have been carried out to determine the solution stoichiometry of silver(I) 3,5-bis (trifluoromethyl)pyrazolate species. This compound exists as a trimer in the solid state (n = 3) but in solutions of chlorinated solvents, the DOSY data suggest the presence of a mixture of solvent stabilized monomer (n = 1) and dimer (n = 2) in equilibrium. Different approximations have been used including the Stokes–Einstein and the Stokes– Einstein–Gierer–Wirtz equations. Some methodological problems are discussed., National Science Foundation, Grant/ Award Number: CHE-1954456 (HVRD); Consejería de Educación e Investigación Comunidad de Madrid, Grant/Award Number: PS2018/EMT-4329 AIRTEC-CM; Ministerio de Ciencia e Innovación, Grant/Award Number: Project PGC2018‐ 094644‐B‐C22

Treatment of bis(pyrazolyl)borate ligand supported [(CF

Non-porous small molecule adsorbents such as {[3,5-(CF3 )2 Pz]Cu}3 (where Pz=pyrazolate) are an emerging class of materials that display attractive features for ethene-ethane separation. This work examines the chemistry of fluorinated copper(I) pyrazolates {[3,5-(CF3 )2 Pz]Cu}3 and {[4-Br-3,5-(CF3 )2 Pz]Cu}3 with much larger 1-butene in both solution and solid state, and reports the isolation of rare 1-butene complexes of copper(I), {[3,5-(CF3 )2 Pz]Cu(H2 C=CHC2 H5 )}2 and {[4-Br-3,5-(CF3 )2 Pz]Cu(H2 C=CHC2 H5 )}2 and their structural, spectroscopic, and computational data. The copper-butene adduct formation in solution involves olefin-induced structural transformation of trinuclear copper(I) pyrazolates to dinuclear mixed-ligand systems. Remarkably, larger 1-butene is able to penetrate the dense solid material and to coordinate with copper(I) ions at high molar occupancy. A comparison to analogous ethene and propene complexes of copper(I) is also provided.

The chemistry of coinage metal ions with Fe(CO)

In this study, four new N-(alkyl/aryl)imidazolium-borates were prepared, and their deprotonation reactions were investigated. Addition of BH3&bull, THF to N-benzylimidazoles and N-mesitylimidazoles leads to imidazolium-trihydridoborate adducts. Ammonium tetraphenylborate reacts with benzyl- or mesityl-imidazoles with the loss of one of the phenyl groups yielding the corresponding imidazolium-triphenylborates. Their authenticity was confirmed by CHN analysis, 1H-NMR, 13C-NMR, 11B-NMR, FT-IR spectroscopy, and electrospray ionization mass spectrometry (ESI-MS). 3-Benzyl-imidazolium-1-yl)trihydridoborate, (HImBn)BH3, and (3-mesityl-imidazolium-1-yl)trihydridoborate, (HImMes)BH3, were also characterized by X-ray crystallography. The reactivity of these new compounds as carbene precursors in an effort to obtain borate-NHC complexes was investigated and a new carbene-borate adduct (which dimerizes) was obtained via a microwave-assisted procedure.

This work reports the calculation of the nuclear magnetic resonance (NMR) chemical shifts of eight trinuclear Ag(I) complexes of pyrazolate ligands using the relativistic program ZORA. The data from the literature concern exclusively H, C, and F nuclei. For this reason, one of the complexes that is derived from 3,5-bis-trifluoromethyl-1H-pyrazole has been studied anew, and the N and Ag chemical shifts determined for the first time in solution. Solid-state NMR data of this compound have been obtained for some nuclei (H, C, and F) but not for others (N, N, and Ag)., Welch Foundation, Grant/Award Number: Y-1289; Dirección General de Investigación en Innovación de la Comunidad de Madrid, Grant/Award Number: PS2018/EMT-4329 AIRTEC-CM; Ministerio de Ciencia, Innovación y Universidades, Grant/Award Number: PGC2018-094644-B-C2

The trinuclear copper(I) pyrazolate complex [Cu3 ] rearranges to the dinuclear analogue [Cu2 ⋅(C2 H4 )2 ] when exposed to ethylene gas. Remarkably, the [Cu3 ]↔[Cu2 ⋅(C2 H4 )2 ] rearrangement occurs reversibly in the solid state. Furthermore, this transformation emulates solution chemistry. The bond-making and breaking processes associated with the rearrangement in the solid-state result in an observed heat of adsorption (-13±1 kJ mol-1 per Cu-C2 H4 interaction) significantly lower than other Cu-C2 H4 interactions (≥-24 kJ mol-1 ). The low overall heat of adsorption, "step" isotherms, high ethylene capacity (2.76 mmol g-1 ; 7.6 wt % at 293 K), and high ethylene/ethane selectivity (136:1 at 293 K) make [Cu3 ] an interesting basis for the rational design of materials for low-energy ethylene/ethane separations.

Quantum-chemical density functional theory calculations using the BP86 functional in conjunction with a triple-ζ basis set and dispersion correction by Grimme with Becke-Johnson damping D3(BJ) were performed for the title molecules. The nature of the bonding was examined with the quantum theory of atoms in molecules (QTAIM) and natural bond order (NBO) methods and with the energy decomposition analysis in conjunction with the natural orbital for chemical valence (EDA-NOCV) analysis. The energetically lowest-lying form of Fe2(CO)9 is the triply bridged D3h structure, whereas the most stable structures of Ru2(CO)9 and Os2(CO)9 are singly bridged C2 species. The calculated reaction energies for the formation of the cyclic trinuclear carbonyls M3(CO)12 from the dinuclear carbonyls M2(CO)9 are in agreement with experiment, as the iron complex Fe2(CO)9 is thermodynamically stable in these reactions, but the heavier homologues Ru2(CO)9 and Os2(CO)9 are not. The metal–CO bond to the bridging CO ligands is stronge...

Copper(I) complexes supported by fluorinated 1,3,5-triazapentadienyl ligands have been used as catalysts for the oxidation of anthracene, naphthalene, and pyrene to the corresponding quinones, using H2O2 as an oxidant under mild conditions without an acid co-catalyst. Gas chromatography-vacuum ultraviolet spectroscopy (GC-VUV) combined with time-dependent density functional theory theoretical computations of absorption spectra was demonstrated as a new and useful tool-set for unknown determination in complex reaction mixtures, especially when standards are not available for spectral comparisons and product mixtures involve closely related isomers. The anthracene has been converted to 9,10-anthraquinone in quantitative yield using this copper catalyzed process. The oxidation of naphthalene afforded 1,4-naphthoquinone as the major product, and 1-naphthol and 2-naphthol as minor products. The pyrene oxidation resulted in 4,5-, 1,6-, and 1,8-pyrenequinones, among other products. The X-ray crystal structure of [N{(CF3)C(C6F5)N}2]CuNCCH3 is also reported.