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Gold coordination chemistry and catalysis involving unsaturated hydrocarbons such as olefins have experienced a remarkable growth during the last few decades. Despite the importance, isolable and well-characterized molecules with ethylene, the simplest and the most widely produced olefin, on gold are still limited. This review aims to cover features of, and strategies utilized to stabilize, gold–ethylene complexes and their diverse use in chemical transformations and homogeneous catalytic processes. Isolable and well-authenticated gold–ethylene complexes are important not only for structural, spectroscopic, and bonding studies but also as models for likely intermediates in gold mediated reactions of alkenes and gold–alkene species observed in the gas phase. There has also been development on AuI/III catalytic cycles. Nitrogen based ligands have been the most widely utilized ligand supports thus far for the successful stabilization of gold–ethylene adducts. Gold has a bright future in olefin chemistry and with ethylene. [ABSTRACT FROM AUTHOR]

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 13C‐NMR patterns of the group 11 triad. Here, we account for the role of relativistic effects on olefin‐coinage metal ion interaction for cationic, homoleptic tris‐ethylene, and tris‐norbornene complexes, [M(η2‐C2H4)3]+ and [M(η2‐C7H10)3]+ (M = Cu, Ag, Au), as representative case of studies. The M‐(CC) bond strength in the cationic, tris‐ethylene complexes is affected sizably for Au and to a lesser extent for Ag and Cu (48.6%, 16.7%, and 4.3%, respectively), owing to the influence on the different stabilizing terms accounting for the interaction energy in the formation of coinage metal cation‐π complexes. The bonding elements provided by olefin → M σ‐donation and olefin ← M π‐backbonding are consequently affected, leading to a lesser covalent interaction going down in the triad if the relativistic effects are ignored. Analysis of the 13C‐NMR tensors provides further understanding of the observed experimental values, where the degree of backbonding charge donation to π2*‐olefin orbital is the main influence on the observed high‐field shifts in comparison to the free olefin. This donation is larger for ethylene complexes and lower for norbornene counterparts. However, the bonding energy in the later complexes is slightly stabilized given by the enhancement in the electrostatic character of the interaction. Thus, the theoretical evaluation of metal‐alkene bonds, and other metal‐bonding situations, benefits from the incorporation of relativistic effects even in lighter counterparts, which have an increasing role going down in the group. [ABSTRACT FROM AUTHOR]

Homoleptic, tetranuclear copper(I) pyrazolates {[3,5-(t-Bu)2Pz]Cu}4, {[3-(CF3)-5-(t-Bu)Pz]Cu}4, and {[4-Br-3,5-(i-Pr)2Pz]Cu}4 are excellent stand-alone catalysts for azide–alkyne cycloaddition reactions (CuAAC). This work demonstrates that a range of pyrazolates, including those with electron donating and electron-withdrawing groups to sterically demanding substituents on the pyrazolyl backbones, can serve as effective ligand supports on tetranuclear copper catalysts. However, in contrast to the tetramers and also highly fluorinated {[3,5-(CF3)2Pz]Cu}3, trinuclear copper(I) complexes such as {[3,5-(i-Pr)2Pz]Cu}3 and {[3-(CF3)-5-(CH3)Pz]Cu}3 supported by relatively electron rich pyrazolates display poor catalytic activity in CuAAC. The behavior and degree of aggregation of several of these copper(I) pyrazolates in solution were examined using vapor pressure osmometry. Copper(I) complexes such as {[3,5-(CF3)2Pz]Cu}3 and {[3-(CF3)-5-(t-Bu)Pz]Cu}4 with electron withdrawing pyrazolates were found to break up in solution to different degrees producing smaller aggregates while those such as {[3,5-(i-Pr)2Pz]Cu}3 and {[3,5-(t-Bu)2Pz]Cu}4 with electron rich pyrazolates remain intact. In addition, kinetic experiments were performed to understand the unusual activity of tetranuclear copper(I) pyrazolate systems. [ABSTRACT FROM AUTHOR]

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)(CO)], as well as the free ligand 2,6-bis­(3,5-di-p-tolyl­pyrrol-2-yl)pyridine, C41H33N3 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Described herein is the synthesis and photophysics of two tetranuclear copper complexes, {[3,5-(Pri)2,4-(Br)Pz]Cu}4 and {[3-(CF3),5-(But)Pz]Cu}4 tailor-designed by manipulating the pyrazolyl ring substituents. Unlike their trinuclear analogues, the luminescence of the tetranuclear species is molecular (not supramolecular) in nature with extremely high solid-state quantum yields of ∼80% at room temperature. [ABSTRACT FROM AUTHOR]

The chemistry of trinuclear silver(I) and copper(I) pyrazolates with aromatic, bidentate N‐heterocycles, 2,2′‐bipyridine, 6,6′‐dimethyl‐2,2′‐bipyridine, 1,10‐phenanthroline, 2,9‐dimethyl‐1,10‐phenanthroline, and 1,8‐naphthyridine are presented. These N‐donor ligands react readily with {[3,5‐(CF3)2Pz]Ag}3 and {[3,5‐(CF3)2Pz]Cu}3 providing mixed‐ligand complexes with all nitrogen coordination spheres at metal in high yield. The fluorinated pyrazolate acts as a bridging ligand in these complexes. The bipyridine and phenanthroline systems with donor lone pairs at an acute angle serve as bidentate chelators for copper and silver providing dinuclear complexes. They feature planar, boat or chair shaped Ag2N4 or Cu2N4 cores and four‐coordinate, tetrahedral metal sites. The 1,8‐naphthyridine that has donor nitrogen lone pairs at a parallel orientation affords trinuclear copper and silver complexes with two‐ and three‐coordinate metal centers. It uses only one of its lone pairs effectively in these adducts for metal ion coordination. In addition, 1,8‐naphthyridine moieties of these copper and silver complexes show intermolecular π–π stacking. Results presented here show the effects of donor nitrogen lone‐pair orientations of the bidentate N‐heterocycles on the structures of the products resulting from their chemistry with {[3,5‐(CF3)2Pz]Ag}3 and {[3,5‐(CF3)2Pz]Cu}3. [ABSTRACT FROM AUTHOR]

Sterically loaded, anionic pyridine has been synthesized and utilized successfully in the stabilization of a isoleptic series of coinage metal complexes. The treatment of [4‐(Ph3B)‐2,6‐Trip2Py]K (Trip=2,4,6‐iPr3C6H2) with CuBr(PPh3), AgCl(PPh3) or AuCl(PPh3) (Py=pyridine) afforded the corresponding [4‐(Ph3B)‐2,6‐Trip2Py]M(PPh3) (M=Au, Ag, Cu) complexes, via salt metathesis, as isolable, crystalline solids. Notably, these reactions avoid the facile single electron transfer chemistry reported with the less bulky ligand systems. The X‐ray structures revealed that they are two‐coordinate metal adducts. The M−N and M−P bond distances are longest in the silver and shortest in the copper adduct among the three group 11 family members. Computational analysis revealed an interesting stability dependence on steric bulk of the anionic pyridine (i. e., pyridyl borate) ligand. A comparison of structures and bonding of [4‐(Ph3B)‐2,6‐Trip2Py]Au(PPh3) to pyridine and m‐terphenyl complexes, {[2,6‐Trip2Py]Au(PPh3)}[SbF6] and [2,6‐Trip2Ph]Au(PPh3) are also provided. The Au(I) isocyanide complex, [4‐(Ph3B)‐2,6‐Trip2Py]Au(CNBut) has been stabilized using the same anionic pyridylborate illustrating that it can support other gold‐ligand moieties as well. [ABSTRACT FROM AUTHOR]

Phenanthroline-based ligands with bulky aryl groups flanking the metal binding pocket enabled the synthesis and detailed investigation of ethylene complexes of copper(I), silver(I), and gold(I), including structural data of [{2,9-bis(2,4,6-triisopropylphenyl)-1,10-phenanthroline}M(C2H4)][SbF6] (M = Cu, Ag, Au), Additionally, a related copper(I)-ethylene complex with a highly fluorinated ligand is also reported. Gold(I) affects the ethylene moiety significantly as evident from the notable upfield coordination shifts of ethylene carbon signals in the NMR and lengthening of the ethylene C＝C bond length. Silver(I) forms the weakest bond with ethylene in this series of isoleptic, group 11 metal-ethylene complexes. Preliminary catalytic investigations underscore the potential of copper complexes, particularly those with weakly coordinating supporting ligands, as effective catalysts for C(sp3)–H functionalization through trifluoromethyl carbene insertion. [ABSTRACT FROM AUTHOR]

In the course of studying Diels–Alder reactions of 4-vinylimidazoles with N-phenylmaleimide, it was discovered that they engage in cycloaddition at room temperature to give high yields of the initial cycloadduct as a single stereoisomer. In certain cases, the product precipitated out of the reaction mixture and could be isolated by simple filtration, thereby avoiding issues with aromatization observed during chromatographic purification. Given these results, intramolecular variants using doubly activated dienophiles were also investigated at room temperature. Amides underwent cycloaddition at room temperature in modest yields, but the initial adducts were not isolable with Nimid-benzyl-protected systems. Attempts to extend these results to the corresponding esters and hydroxamate were less successful with these substrates only undergoing cycloaddition at elevated temperatures in lower yields. Density functional theory calculations were performed to evaluate the putative transition states for both the inter- and intramolecular variants to rationalize experimental observations. [ABSTRACT FROM AUTHOR]

Zinc complexes [{(3,5-(CF3)2Pz)ZnEt}2(μ-THF)] (1), [{(3-(CF3),5-(t-Bu)Pz)ZnEt}2(μ-THF)] (2), and [{(3,5-(i-Pr)2Pz)ZnEt}2(μ-THF)] (3) adopt dinuclear structures with zinc sites bridged by a THF molecule and two pyrazolate ligands. The zinc complex 1 that features the weakest donating pyrazolate is the best catalyst among the three for the aziridination of styrene and cis-cyclooctene with PhI=NTs. [ABSTRACT FROM AUTHOR]

Background/objectives: Several studies reported associations of the lactase gene (LCT) polymorphism -13910C>T (rs4988235) with obesity-related variables and obesity in adults. This study aimed to replicate previously reported associations in a population sample of Portuguese young adults.Subjects/methods: We genotyped 447 subjects from central and northern regions of Portugal (mean age 20.81±4.24 years) for the lactase variant -13910C>T (rs4988235), using TaqMan probes. Anthropometric variables (weight, height and body fat) were measured using standardized procedures and body mass index (BMI) (kg/m2) was calculated.Results: Frequency of genotypes was 35.8% CC (lactase nonpersistent, LNP), 48.1% CT and 16.1% TT, consistent with Hardy-Weinberg equilibrium (P=1). The frequency for the minor -13910 T allele was 0.402. Assuming a dominance model for the lactase persistence (LP) minor T-allele, linear regression models showed statistically significant associations between the LP genotype CT/TT and BMI, fat mass and weight (β=1.114, P=0.003; β=1.309, P=0.007 and β=2.67, P=0.021, respectively) after adjustment for age and sex. In concordance, logistic regression showed significant association between LP genotype CT/TT and overweight/obesity (OR=1.77; CI 1.08-2.92; P=0.023), as well as with high fat percentage ranges (OR=1.58; CI 1.01-2.46; P=0.041), when adjusting for age and sex. No significant interaction was obtained between the LCT polymorphism and physical activity for BMI (Pint=0.454) or FAT % (Pint=0.421).Conclusions: In the Portuguese sample of young adults, the lactase -13910C>T polymorphism revealed significant associations with the obesity-related anthropometric variables BMI, fat mass and weight, and previously observed associations with the obesity risk were also confirmed. [ABSTRACT FROM AUTHOR]

Ultrasound-assisted transformations of copper-containing compounds in aqueous media were studied. Metallic copper powder, its oxides, copper(II) hydroxide, and a series of distinct soluble and insoluble copper salts were treated by ultrasound in water solutions or suspensions in temperature ranges of 15–20°C and 55–60°C. In some cases, the reactions were carried out in presence of organic solvents, oxidants, and reductants, as well as upon their simultaneous application. Spherical ultrasmall copper(II) oxide particles (2–7 nm in size) were obtained in several systems with quantitative yields; an impurity of CuH is registered in the mixture. Conditions leading to the formation of CuO or metallic copper nanoparticles in ultrasonic conditions were established. [ABSTRACT FROM PUBLISHER]

In this paper, the reactions are revisited, with the goal of obtaining spectroscopic factors (SF) for the transition to the ground state of some residual nuclei, applying the distorted wave Born approximation (DWBA). The double-folding São Paulo Potential (SPP) was used to derive the distorted wave function in the entrance and exit channels. The derived SF are compared with the results of extensive shell model calculations showing a rather good agreement. [ABSTRACT FROM AUTHOR]

A unique four‐coordinate, classical gold(I)‐carbonyl complex with substantial backdonation from gold has been isolated by using a B‐methylated and fluorinated tris(pyridyl)borate chelator. Its lighter silver(I) and copper(I) analogs enabled a study of trends in the coinage‐metal family. The B‐arylated ligand version also afforded a gold–carbon monoxide complex that displays a notably low C−O stretch value, but with trigonal planar geometry at the gold. A computational analysis shows that the AuI−CO bonds of these tris(pyridyl)borate ligand‐supported molecules consist of electrostatic attraction, OC→Au σ‐donation, and very significant Au→CO π‐back‐bonding components. The latter is responsible for the observed C−O stretching frequencies, which are lower than in free CO. [ABSTRACT FROM AUTHOR]

X-ray crystal structural data at 100 (2) K for the thallium(I) complex of a fluorinated bis(pyrazolyl)borate, {bis[3,5-bis(trifluoromethyl)-1 H-pyrazol-1-yl-κ N2]borato}thallium(I), [Tl(C10H4BF12N4)], abbreviated as [H2B{3,5-(CF3)2pz}2]Tl, and the related tris(pyrazolyl)borate, {tris[3,5-bis(trifluoromethyl)-1 H-pyrazol-1-yl-κ N2]borato}thallium(I), [Tl(C15H4BF18N6)], abbreviated as [HB{3,5-(CF3)2pz}3]Tl, are reported. [H2B{3,5-(CF3)2pz}2]Tl features a two-coordinate TlI atom with a bent geometry and a boat-shaped bis(pyrazolyl)borate ligand. It also has several additional inter- and intramolecular Tl...H and Tl...F contacts in the solid state. The tris(pyrazolyl)borate analogue [HB{3,5-(CF3)2pz}3]Tl has a trigonal-pyramidal thallium centre and features inter- and intramolecular Tl...F contacts. [ABSTRACT FROM AUTHOR]

The reaction of the di-lithiated oxamide of 1 with two equivalents of SnCl2 provided the tin trans-oxamide 3. In solution, spectroscopic analysis suggests exclusively the formation of a trans-oxamide ( trans- 3). However, the solid state shows an atypical cis-oxamide ( cis- 3), where the oxamide fragment acts as an anti-Janus head ligand. An 119Sn-NMR variable temperature experiment ([D8]THF) of the trans-oxamide ( trans- 3) was performed however, at lower temperature no additional signal was observed, which confirmed the absence of a dynamic equilibrium. Dispersion-corrected density functional calculations revealed that the cis conformation of this tin(II) oxamide complex is more stable than the trans isomer by 1.4 kcal ·mol-1. [ABSTRACT FROM AUTHOR]

Treatment of Li[PhBH3] with excess 3-(C2F5)PzH led to the B-phenylated tris(pyrazolyl)borateligandas its lithium salt [PhB(3-(C2F5)Pz)3]Li. This ligand enabled the isolation of thermally stable group11 metal ethylene adducts [PhB(3-(C2F5)Pz)3]M(C2H4) (M = Au, Ag, Cu). They werecharacterized by spectroscopy and by X-ray crystallography. Theseethylene adducts are structurally similar and feature three-coordinatetrigonal-planar metal sites and a κ2-bonded tris(pyrazolyl)borateligand. They are ideal for examining the trends involving ethylenecomplexes of the group 11 triad. The ethylene 13C NMR resonanceof the [PhB(3-(C2F5)Pz)3]M(C2H4) adducts in C6D12appearat δ 58.9, 101.6, and 85.5 ppm, respectively, for M = Au, Ag,Cu. The M–C and M–N bond distances are largest in thesilver complex and smallest in the copper complex. [ABSTRACT FROM AUTHOR]

The tris(pyrazolyl)borate [HB(3,5-(CF3)2Pz)3]- prepared using highly fluorinated 3,5-bis(trifluoromethyl)pyrazole and BH4- is an excellent supporting ligand for the stabilization of a number of rare organometallic complexes of coinage metals. For example, it has enabled the isolation of Cu(I), Ag(I), and Au(I) complexes of CO and ethylene as crystalline solids. Syntheses, spectroscopic and structural features, and properties of [HB(3,5-(CF3)2Pz)3]ML (M = Cu, Ag, Au; L = CO, C2H4) are the main focus of this discussion. Several metal adducts based on the tris(triazolyl)borate [HB(3,5-(CF3)2Tz)3]- supporting ligand as well as the cationic, coinage metal multi-alkene complexes containing the [SbF6]- counterion are also discussed. [ABSTRACT FROM AUTHOR]

Tris(pyrazolyl)borates are used extensively in metal coordination chemistry and belong to a class of ligands generally referred to as scorpionates. The steric and electronic properties of these ligands can be modified quite easily by varying the substituents on the 3-, 4-, and 5-positions of the pyrazolyl moieties on the B atom. Fluorinated tris(pyrazolyl)borates are useful in the stabilization of rare silver(I) complexes. The silver(I) adduct (acetonitrile-κ N){tris[5-methyl-3-(trifluoromethyl)pyrazol-1-yl-κ N2]hydroborato}silver(I), [Ag(C15H13BF9N6)(CH3CN)] or [HB{3-(CF3),5-(CH3)Pz}3]AgNCCH3, was obtained by treating [HB{3-(CF3),5-(CH3)Pz}3]Na with CF3SO3Ag in the presence of acetonitrile, and was isolated in 85% yield. Single-crystal X-ray diffraction analysis reveals that the AgI center has a pseudo-tetrahedral all-nitrogen coordination sphere, and is supported by a tris(pyrazolyl)borate ligand that binds to the AgI center in a κ3-fashion. [ABSTRACT FROM AUTHOR]

A series of thermally stable, easily isolable, monomeric, and isoleptic coinage metal alkyne complexes have been reported. Treatment of [N((C3F7)C(Dipp)N)2)Li (the lithium salt of the 1,3,5- triazapentadiene [N((C3F7)C(Dipp)N)2]H) with AuCI, CF3SO3Ag or CF3SO3Cu in the presence of 3-hexyne led to the corresponding coinage metal alkyne complex [N((C3F7)C(Dipp)N)2]M(EtCCEt) in good yield (M = Au, Ag, Cu; Dipp = 2,6-diisopropylphenyl). X-ray crystal structures of the three coinage metal alkynes are remarkably similar, and show the presence of trigonal-planar metal sites with η2-bonded 3-hexyne. The M-C and M-N bond distances vary in the order Cu < Au < Ag. The bending of the C-CC bond angle is largest for the gold, followed by Cu and Ag adducts. The gold adduct also shows the largest decrease in CC stretching frequency in Raman, while the Ag adduct shows the smallest change compared to that of the uncoordinated alkyne. DFT calculations on [N((CF3)C(Ph)N)2]M(EtCCEt) and the related ClM(EtCCEt) predict that the M-alkyne bond energy varies in the order Ag

The article presents a chemical review which describes the developments of carbonyl and olefin adducts of coinage metals. It explains that coinage metals are supported by poly (pyrazolyl) borate and poly (pyrazolyl) alkane ligands and silver mediated atom transfer reactions. It also provides an overview of a growing area of investigation of the use of modified tris (pyrazolyl) borates and related pyrazole-based ligands.

The first 5-substituted trihydro(azolyl)borate system, the sodium trihydro(5-CF3-pyrazol-1-yl)borate, Na[H3B(5-(CF3)-pz)], has been synthesized by the reaction of 3-trifuoromethyl-pyrazole with NaBH4 in high yield. Na[H3B(5-(CF3)-pz)] reacts with AgNO3 in the presence of monodentate tertiary phosphanes PR3 (PR3 = P(C6H5)3, P(p-C6H4CH3)3, P(m-C6H4CH3)3, P(o-C6H4CH3)3, or PCH3(C6H5)2) to afford silver(l) bis(phosphane) adducts. These compounds have been characterized by elemental analyses, FTIR, ESI-MS, and multinuclear (¹H, 19F, and 31P) NMR spectroscopy. Solid-state structures of {H3B(5-(CF3)pz)]Ag[P(C6H5)3]2} and {[H3B(5-(CF3)pz)]Ag[P(p-C6H4CH3)3]2} are also reported. They feature κ²-N,H-bonded trihydro(pyrazolyl)borate ligands and pseudo-tetrahedral silver atoms. [ABSTRACT FROM AUTHOR]

Silver pyrazolates {[3-(CF3)Pz]Ag}3, {[3-(CF3) ,5-(CH3)Pz]Ag}3, {[3-(CF3),5-(Ph)Pz]Ag}3, {[3-(CF3),5-(But)Pz]Ag}3, and {[3-(C3F7),5-(But)Pz]Ag}3 have been synthesized by treatment of the corresponding pyrazole with a slight molar excess of silver(I) oxide. This economical and convenient route gives silver pyrazolates in high (>80%) yields. X-ray crystal structures of {[3-(CF3),5-(CH3)Pz]Ag}3, {[3-(CF3),5-(But)Pz]Ag}3, and {[3-(C3F7),5-(But)Pz]- Ag}3 show that these molecules have trinuclear structures with essentially planar to highly distorted Ag3N6 metallacycles. {[3-(CF3),5-(CH3)Pz]Ag}3 forms extended columns via intertrimer argentophilic contacts (the closest Ag⋯Ag separation between the neighboring trimers are 3.355 and 3.426 Å). The trinuclear {[3-(CF3),5-(But)Pz]-Ag}3 units crystallize in pairs, basically forming "dimers of trimers", with the six silver atom core of the adjacent trimers adopting a chair conformation. However, in these dimers of trimers, even the shortest intertrimer Ag⋯Ag distance (3.480 Å) is slightly longer than the van der Waals contact of silver (3.44 Å). {[3-(C3F4,5-(But)Pz]Ag}3, which has two bulky groups on each pyrazolyl ring, shows no close intertrimer Ag⋯Ag contacts (closest intertrirner Ag⋯Ag distance = 5.376 Å). The Ag-N bond distances and the intratrimer Ag⋯Ag separations of the silver pyrazolates do not show much variation. However, their N-Ag-N angles are sensitive to the nature (especially, the size) of substituents on the pyrazolyl rings. The ax-acidic {[3,5-(CF3)2Pz]Ag}3 and {[3-(C3F7),5-(But)Pz]Ag}3 form adducts with the π-base toluene. X-ray data show that they adopt extended columnar structures of the type {[Ag3]2·[toluenel}∞, and {[Ag3]′·[toluene]}∞ ({[3,5-(CF3)2Pz]Ag}3 = [Ag3], {[3-(C3F7),5-(But)Pz]Ag}3 = [Ag3]′), in which toluene interleaves and makes face-to-face contacts with {[3-(C3F7),5-(But)Pz]Ag}3 or dimers of {[3,5-(CF3]2- Pz]Ag}3. [ABSTRACT FROM AUTHOR]

This review presents an overview of fluorinated tris(pyrazolyl)borate ligands and their role in the development of silver adducts containing group 14 ligands. Tris(pyrazolyl)borates bearing fluorocarbon substituents are sterically somewhat similar but electronically very different from their hydrocarbon counterparts. They have weakly donating nitrogen sites. Fluorinated hydridotris(pyrazolyl)borates also have less reducing B-H groups. These mono-anionic, nitrogen-based donors are ideal supporting ligands to stabilize silver complexes bearing labile donors. For example, fluorinated tris(pyrazolyl)borates have enabled the isolation of thermally stable Ag(I)-CO, Ag(I)-ethylene, and Ag(I)-acetylene adducts. Compounds with unsupported Ag(I)-Ge(II) and Ag(I)-Sn(II) bonds have also been synthesized. Most of these contain easily removable halide groups and silver atoms in the same molecule, but do not show the silver-halide metathesis. Fluorinated tris(pyrazolyl)borate ligands without the problematic B-H moiety have been reported. They afford silver-tris(pyrazolyl) borates with higher solution stability. The κ3-coordination mode is the most common for tris(pyrazolyl)borates but κ2-bonded tris(pyrazolyl)borate silver adducts are also known. Some silver adducts of fluorinated tris(pyrazolyl)borates are excellent tris(pyrazolyl)borato ligand transfer agents, promising homogeneous catalysts and effective antimicrobial agents. [ABSTRACT FROM AUTHOR]

Synthetic details, solid-state structures, and photophysical properties of a group of trimeric copper- (1) complexes containing pyrazolate ligands are described. The reaction of copper(l) oxide and the fluorinated pyrazoles [3-(CF3)Pz]H, [3-(CF3),5-(Me)Pz]H, and [3-(CF3),5-(Ph)Pz}H leads to the corresponding trinuclear copper(l) pyrazolates, {[3-(CF3)Pz]Cu}3, {[3-(CF3),5-(Me)Pz]Cu}3, and {[3-(CF3),5-(Ph)Pz]Cu}3, respectively, in high yield. The {[3,5-(i-Pr)2Pz]Cu}3 compound was obtained by a reaction between [Cu(CH3CN)4][BF4], [3,5-(i-Pr)2Pz]H, and NEt3. These compounds as well as {[3,5-(Me)2Pz]Cu}3 and {[3,5-(CF3)2Pz]Cu}3 adopt trimeric structures with nine-membered Cu3N6 metallacycles. There are varying degrees and types of intertrimer Cu....Cu interactions. These contacts give rise to zigzag chains in the fluorinated complexes, {[3-(CF3)Pz]Cu}3, {[3-(CF3), 5-(Me)Pz]Cu}3, {[3-(CF3),5-(Ph)Pz]Cu}3, and {[3,5-(CF3)2Pz]Cu}3, whereas the nonfluorinated complexes, {[3,5-(Me)2Pz]Cu}3 and {[3,5-(i-Pr)2Pz]Cu}3 form dimers of trimers. Out of all the compounds examined in this study, {[3-(CF3),5-(Ph)Pz]Cu}3 has the longest (3.848 Å) and {[3,5-(Me)2Pz]- Cu}3 has the shortest (2.946 Å) next-neighbor intertrimer Cu...Cu distance. The Cu...Cu separations within the trimer units do not vary significantly (typically 3.20-3.26 Å). All of these trinuclear copper(l) pyrazolates show bright luminescence upon exposure to UV radiation. The luminescence bands are hugely red-shifted from the corresponding lowest-energy excitations, rather broad, and unstructured even at low temperatures, suggesting metal-centered emissions owing to intertrimer Cu...Cu interactions that are strengthened in the phosphorescent state. The {[3-(CF3),5-(Ph)Pz]Cu}3 compound exhibits an additional highly structured phosphorescence with a vibronic structure corresponding to the pyrazolyl (Pz) ring. The luminescence properties of solids and solutions of the trimeric compounds in this study show fascinating trends with dramatic sensitivities to temperature, solvent, concentration, and excitation wavelengths. [ABSTRACT FROM AUTHOR]

The fluorinated bis(pyrazolyl)borate [H2B(3,5-(CF3)2Pz)2]− allows the isolation of thermally stable copper(I) complexes containing phosphorus and nitrogen based donors, alkyne and alkene ligands. [H2B(3,5-(CF3)2Pz)2]Cu(PPh3), [H2B(3,5-(CF3)2Pz)2]Cu(NCCH3) and {[H2B(3,5-(CF3)2Pz)2]Cu}2(1,5-COD) were synthesized by using [H2B(3,5-(CF3)2Pz)2]K, CF3SO3Cu, and the appropriate ligand, PPh3, NCCH3 or 1,5-COD. [H2B(3,5-(CF3)2Pz)2]Cu(HC≡CPh) and [H2B(3,5-(CF3)2Pz)2]Cu(H2C=CHPh) were obtained by treating [H2B(3,5-(CF3)2Pz) 2]Cu(NCCH3) with phenylacetylene and styrene, respectively. X-ray data show that [H2B(3,5-(CF3)2Pz)2]CuL (where L = PPh3, HCCPh, H2C=CHPh) and {[H2B(3,5-(CF3)2Pz)2]Cu}2(1,5-COD) have three-coordinate, trigonal planar copper sites. The bis(pyrazolyl)borate moiety adopts the common boat conformation. The νC≡C stretching band of [H2B(3,5-(CF3)2Pz)2]Cu(PhC≡CH) was observed at 1927 cm−1. Structural and spectroscopic data of the alkene and alkyne complexes indicate minimal back-bonding from the d10 copper(I) center. [Copyright &y& Elsevier]

A cationic gold carbonyl complex has been synthesized and characterized using several techniques including X-ray crystallography. [(Mes3P)Au(CO)] [SbF6] (Mes = 2,4,6-Me3C6H2) has a linear, two-coordinate gold atom. This compound displays the Co stretching frequency at 2185 cm-1.The 13C NMRsignal of the gold-bound 13CO appears as a doublet centered at δ 182.6 (²JC,P = 115 Hz). A computational study shows that the Au-CO bond consists of electrostatic attraction, Au CO donation, and significant Au → CO π-back-bonthng components. Polarization of the CO bond caused by the electrostatic effect of the cationic gold center is mainly responsible for the large blue shift in the CO stretching frequency. [ABSTRACT FROM AUTHOR]

A rare gold(I) ethylene complex and the closely related copper(I) ethylene adduct have been isolated using [N{(C3F7)C(2,6-Cl2C6H3)N}2] as the supporting ligand. [N{(C3F7)C(2,6-Cl2C6H3)-N}2]Au(C2H4) (1) is an air-stable solid. It features a U-shaped triazapentadienyl ligand backbone and a three-coordinate, trigonal- planar gold center. The copper(I) adduct [N{(C3F7)C(2,6-Cl2C6H3)-N}2]Cu(C2H4) (2) also has a similar structure. The 13C NMR signal corresponding to the ethylene carbons of 1 appears at about 64 ppm upfield from the free ethylene, while the ethylene carbons of 2 show a relatively smaller (39 ppm) upfield shift. [N{(C3F7)C(2,6-Cl2C6H3)N}2]M(C2H4) (M = Cu, Au) mediate carbene-transfer reactions from ethyl diazoacetate to saturated and unsaturated hydrocarbons. [ABSTRACT FROM AUTHOR]

CuI and AgI complexes of the fluorinated triazolate ligand [3,5- (C3F7)2Tz]- have been synthesized using the corresponding metal(l) oxides and the triazole. They form π-acid/base adducts with toluene, leading to [Tol][M3][Tol] ([Tol] = toluene; [M3] = {[3,5- (C3F7)2Tz]Cu}3 or {[3,5-(C3F7)2Tz]Ag}3) type structures. Packing diagrams show the presence of extended chains of the type {[ToI][M3][ToI]}∞, but the intertoluene ring distances are too long for significant π-arene/π-arene contacts. These copper and silver triazolates react with PPh3 (at a 1:1 metal ion/P molar ratio), leading to dinuclear {[3,5-(C3F7)2Tz]Cu(PPh3)}2 and {[3,5-(C3F7)2Tz]Ag-(PPh3)}2. They feature a six-membered Cu(μ-N-N)2Cu or Ag(μ-N-N)2Ag core with a boat conformation. [ABSTRACT FROM AUTHOR]

The synthesis and X-ray structures of gold(l) adducts supported by β-diketiminates have been reported. {[HC{(H)C(2,4,6-Br3C6H2)N}2]-Au}2 and {[HC{(H)C(Dipp)N}2]Au}2 [Dipp = 2,6-(i-Pr)2C6H3] are easily salable solids and feature 12-membered macrocyclic ring structures. β-Diketiminate ligands adopt a W-shaped conformation. Gold atoms are bonded to the nitrogen atoms in a linear fashion. ¹H NMR signals corresponding to the protons at the βdiketiminate ligand β-C position of the gold adducts appear at a notably high downfield region. [ABSTRACT FROM AUTHOR]

Silver(I) ethylene adducts [PhB(3-(CF3)Pz)3]Ag(C2H4) and [MeB-(3-(CF3)Pz)3]Ag(C2H4) have been synthesized using the corresponding lithium salts, AgOTf, and ethylene. X-ray data show that [PhB(3-(CF3)Pz)3]Ag(C2H4) has a planar three-coordinate silver center whereas [MeB(3-(CF3)Pz)3]Ag(C2H4) features a tetrahedral silver site. The ethylene-free {[PhB(3-(CF3)Pz)3]Ag}n adopts a helical structure with a hexagonal pore. [ABSTRACT FROM AUTHOR]

Fully fluorinated triazapentadienyl ligand [N{(C3F7)C(C6F5)N}2]- and the related [N{(C3F7C(2-F,6-(CF3)C6H3)N}2) have been synthesized in good yield via a convenient route and used in the isolation of three- and four-coordinate copper(l)-carbon monoxide complexes. They show fairly high νCO values (>2100 cm-1), indicating the presence of electron-poor Cu sites. The copper(I)-ethylene adduct [N{(C3F7)C(C6F5)N}2]Cu(C2H4), featuring a three-coordinate Cu site, has also been synthesized using [N{(C3F7)C-(C6F5)N}2]CuNCCH3 and C2H4. [ABSTRACT FROM AUTHOR]

The thallium derivative of a fluorinated, B-methylated, tris(pyrazolyl)borate ligand, [MeB(3-(CF3)Pz)3]-, has been synthesized via a two-step process using the corresponding pyrazole, Li[MeBH3], and thallium(I) acetate. Reaction of [MeB(3-(CF3)Pz)3]TI with CuBr in the presence of ethylene leads to [MeB(3-(CF3)Pz)3]Cu(C2H4). It is a thermally stable solid. [MeB(3-(CF3)Pz)3]Cu(C2H4) reacts with [(Bn)2ATI]SnCl to yield [MeB(3-(CF3)Pz)3]Cu←Sn(Cl)[(Bn)2ATI], featuring an unsupported Cu(I)-Sn(II) bond [2.4540(4) Å]. [ABSTRACT FROM AUTHOR]

The bonding situation of Ag(I)CO complexes having a Scorpionate ligand directly attached to the transition metal has been analyzed in detail by means of relativistic density functional theory calculations. To this end, different experimentally characterized complexes together with other representative species have been considered to rationalize the observed shift of the corresponding ν(CO) stretching frequencies and the influence of the substituents in the Scorpionate ligand. With the help of the energy decomposition analysis method combined with the natural orbital for chemical valence it is found that the main contribution to the bonding comes from the electrostatic attractions between the LAg(I) and CO fragments. Despite that, the LAg → CO π‐backdonation is also significant in these species as well as in related LCu(I)CO complexes. [ABSTRACT FROM AUTHOR]

Presents information on studies of the use of highly fluorinated poly(pyrazolyl)borates ligands in copper(I) isocyanide chemistry and the structural characterization of hydrogen-bridged dimer. Procedures of operations; Synthesis of the complexes; Crystallographic data collection and structure determination; Preparation of the bis[(pyrazolyl)borato]copper complexes.

A useful ligand involving three pyridyl donor arms and fluorocarbon substituents surrounding the coordination pocket has been assembled and utilized in coinage metal chemistry. This tris(pyridyl)borate serves as an excellent ligand support for the stabilization of ethylene complexes of copper, silver and gold. [ABSTRACT FROM AUTHOR]

The Front Cover image illustrates the successful use of an umbrella‐shaped, anionic and super‐bulky pyridyl borate ligand to stabilize two‐coordinate gold(I), silver(I), and copper(I) complexes, and highlights the X‐ray crystal structure of a gold‐triphenyl phosphine complex. More information can be found in the Research Article by H. V. R. Dias and co‐workers (DOI: 10.1002/chem.202401204)...By Mukundam Vanga; Alvaro Muñoz‐Castro and H. V. Rasika DiasReported by Author; Author; Author [Extracted from the article]

Fluorescent organotin compounds are useful in sensing, optoelectronic devices, and in vitro bioimaging. Although in vitro fluorescence bioimaging shows low resolution at room temperature, a better resolution is possible at cryotemperatures. Therefore, the search for new cryoluminescent materials with potential application in high-resolution fluorescence bioimaging remains a great challenge. Herein, we report the cryoluminescence properties of two fluorescent bis-organotin compounds, namely, BisNTHySnBu2 (5) and BisNTHySnPh2 (6), synthesized via microwave irradiation. All compounds were fully characterized using 1H, 13C, and 119Sn NMR spectroscopy, Raman spectroscopy, IR spectroscopy, and HR-MS. The 119Sn δ and 3J(1H,119Sn) of 5 and 6 indicate that two Sn-ligands are chemically and electronically equivalent, as confirmed by cyclic voltammetry. The crystal structure of 6 showed pentacoordinate tin atoms with skeleton ligands. The study of self-assembled monolayers of both Sn-complexes via STM microscopy revealed a similar supramolecular packing in lamella-like patterns, adopting a face-on arrangement, where molecules stay flat lying on HOPG in accordance with the height profile of closely packed monolayers on graphite of about 0.33 nm thickness. However, only the Sn complex 6, which bears phenyls, covers large surface areas. The photophysical properties of bis-organotin compounds were also investigated in solution (room and low temperatures) and in the solid state. Good luminescence properties in solutions with fluorescence quantum yields (Φ) of approximately 35% and 50% were found. Despite this, Φ is quenched in the solid state because of aggregation, as supported by solvent/non solvent fluorescence studies, which is in agreement with STM and AFM investigation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Trinuclear coinage metal metallacycles are obtained when two-coordinate metals are bonded to C, N or N, N anionic ligands of the proper symmetry to form cycles where metals alternate with bridging ligands. Cyclotrimers often exhibit semiplanar structures and mostly columnar or finite stacking in the solid state by means of metallophilic interactions. They show some peculiar properties with an impact on many different fields such as supramolecular architectures, luminescence, molecular recognition, host-guest chemistry, and acid-base chemistry. The comprehensive evaluation of the data shows that, depending on the nature of the central metal and bridging ligand, there is a fine balance of the energy involved in the inter-trimer bond cleavages and the energy gained from the formation of new intermolecular electrostatic interactions, proceeding occasionally to the chemical extreme of redox processes. In this review, a number of important developments are highlighted and systematically analyzed along with structural and computational data and chemical properties to rationalize and build a unifying leitmotif for this chemistry; the focus is made on the authors' contributions in these areas. [ABSTRACT FROM AUTHOR]

The 3d transition metal (Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)) complexes, supported by anions of sterically demanding β-diketones, 1,3-dimesitylpropane-1,3-dione (HLMes) and 1,3-bis(3,5-bis(trifluoromethyl)phenyl)-3-hydroxyprop-2-en-1-one (HLCF3), were synthesized and evaluated for their antitumor activity. To assess the biological effects of substituents on phenyl moieties, we also synthesized and investigated the analogous metal(II) complexes of the anion of the less bulky 1,3-diphenylpropane-1,3-dione (HLPh) ligand. The compounds [Cu(LCF3)2], [Cu(LMes)2] and ([Zn(LMes)2]) were characterized by X-ray crystallography. The [Cu(LCF3)2] crystallizes with an apical molecule of solvent (THF) and features a rare square pyramidal geometry at the Cu(II) center. The copper(II) and zinc(II) complexes of diketonate ligands, derived from the deprotonated 1,3-dimesitylpropane-1,3-dione (HLMes), adopt a square planar or a tetrahedral geometry at the metal, respectively. We evaluated the antitumor properties of the newly synthesized (Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)) complexes against a series of human tumor cell lines derived from different solid tumors. Except for iron derivatives, cellular studies revealed noteworthy antitumor properties, even towards cancer cells endowed with poor sensitivity to the reference drug cisplatin. [ABSTRACT FROM AUTHOR]