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The syntheses of the homoleptic bis(arene) niobium cations [Nb(arene)2]+ (arene = C6H3Me3, C6H5Me) with 16 valence electrons and heteroleptic arene‐carbonyl cations [(CO)Nb(arene)2]+ (arene = C6H3Me3, C6H5Me) and [(arene)M(CO)4]+ (arene = C6H3Me3, C6H6) obeying 18 valence electrons are described. Stabilization of these complexes was achieved by using the weakly coordinating anions [Al(ORF)4]− or [F{Al(ORF)3}2]− (RF = C(CF3)3). The limits of two synthesis routes starting from neutral Nb(arene)2 (arene = C6H3Me3, C6H5Me) or [NEt4][M(CO)6] (M = Nb, Ta) were investigated. All compounds were analyzed by single crystal X‐ray determination, vibrational and NMR spectroscopy. DFT calculations were executed to support the experimental data. [ABSTRACT FROM AUTHOR]

Phosph(III)azanes, featuring the heterocyclobutane P2N2 ring, have now been established as building blocks in main‐group coordination and supramolecular compounds. Previous studies have largely involved their use as neutral P‐donor ligands or as anionic N‐donor ligands, derived from deprotonation of amido‐phosphazanes [RNHP(μ‐NR)]2. The use of neutral amido‐phosphazanes themselves as chelating, H‐bond donors in anion receptors has also been an area of recent interest because of the ease by which the proton acidity and anion binding constants can be modulated, by the incorporation of electron‐withdrawing exo‐ and endo‐cyclic groups (R) and by the coordination of transition metals to the ring P atoms. We observed recently that the effect of P,N‐chelation of metal atoms to the P atoms of cis‐[(2‐py)NHP(μ‐NtBu)]2 (2‐py=2‐pyridyl) not only pre‐organises the N−H functionality for optimum H‐bonding to anions but also results in a large increase in anion binding constants, well above those for traditional organic receptors like squaramides and ureas. Here, we report a broader investigation of ligand chemistry of [(2‐py)NHP(μ‐tNBu)]2 (and of the new quinolyl derivative [(8‐Qu)NHP(μ‐NtBu)]2 (8‐Qu=8‐quinolyl). The additional N‐donor functionality of the heterocyclic substituents and its position has a marked effect on the anion and metal coordination chemistry of both species, leading to novel structural behaviour and reactivity compared to unfunctionalized counterparts. [ABSTRACT FROM AUTHOR]

A fresh look back at the chemistry of Bi3+ spanning solid state structural studies, aqueous biphasic separations, and a chromatographic purification of 213 Bi in support of its clinical use in targeted radiotherapy reveals the foundational importance of coordination chemistry and understanding the preferences exhibited by both the metal center and the ligand(s). Select structural studies of the nitrate and halide salts of Bi3+ complexes with the cyclic crown ethers and acyclic polyethylene glycols (PEGs) are reviewed, and the structure of [BiCl3(cis-anti-cis-dicyclohexano-18-crown-6)] is reported and compared to related structures. Liquid/liquid distribution studies emphasizing Bi3+ partitioning in PEG-based aqueous biphasic systems are presented and show that the distribution ratios using halide anions as extractants increase in the expected order: F- < Cl- < Br- < I-. Building on an understanding of the Bi-directed coordination chemistry in halide containing systems, the rationale for a chromatographic purification of 213 Bi is discussed, as are the performance data showing a 96% recovery of chemically and radionuclidically pure 213 Bi in just 0.25 mL of a strip solution that is directly compatible with binding to carboxylate-based biolocalization agents. The importance of coordination chemistry and an interdisciplinary scientific approach are highlighted, as are select future opportunities in targeted radiotherapy. [ABSTRACT FROM AUTHOR]

Two multi-component crystal structures comprising a carboxylic acid-functionalized imidazolium zwitterion, a p-sulfonatocalix[4]arene anion and aquated metal ion (Na+ or Y3+) with or without an auxiliary component (the 3-methoxyphenyl-triphenylphosphonium cation) are reported. The carboxylic acid-functionalized imidazolium ion binds either as a monodentate or a bidentate ligand depending on the nature of the metal ions, and a bi-layer arrangement prevails in the extended structure regardless of the type of metal ion employed or presence/lack of auxiliary component. [ABSTRACT FROM AUTHOR]

19F magnetic resonance (MR) based detection coupled with well‐designed inorganic systems shows promise in biological investigations. Two proof‐of‐concept inorganic probes that exploit a novel mechanism for 19F MR sensing based on converting from low‐spin (S=0) to high‐spin (S=1) Ni2+ are reported. Activation of diamagnetic NiL1 and NiL2 by light or β‐galactosidase, respectively, converts them into paramagnetic NiL0, which displays a single 19F NMR peak shifted by >35 ppm with accelerated relaxation rates. This spin‐state switch is effective for sensing light or enzyme expression in live cells using 19F MR spectroscopy and imaging that differentiate signals based on chemical shift and relaxation times. This general inorganic scaffold has potential for developing agents that can sense analytes ranging from ions to enzymes, opening up diverse possibilities for 19F MR based biosensing. [ABSTRACT FROM AUTHOR]

Syntheses and characterisation of group ten complexes containing the ligand diphenyl‐2‐(3‐methyl)indolylphosphine are presented herein. The complexes [trans‐PdCl2{PPh2(C9H8N)}2] (1), [cis‐PtCl2{PPh2(C9H8N)}2] (2), [trans‐Pd(CH3)Cl{PPh2(C9H8N)}2] (3) and [trans‐Pt(CH3)Cl{PPh2(C9H8N)}2] (4) have all been structurally characterized by X‐ray crystallography. In all cases, the ligands coordinate to the metal centres via the phosphorus donor atom (κ1‐P) and the pendent NH groups on the indolyl rings of the ligand are orientated so that there is some degree of interaction with the metal–chloride bonds. The unexpected reactivity of 4 with Na[B{3,5‐C6H3(CF3)2}4] is also reported. In this case, the product resulting from this reaction was found to be [Pt{3,5‐C6H3(CF3)2}2{PPh2(C9H8N)}2]. [ABSTRACT FROM AUTHOR]

Quantum chemical studies using density functional theory and ab initio methods have been carried out for the molecules L‐C3‐L with L=PPh3 (1), NHCMe (2, NHC=N‐heterocyclic carbene), and cAACMe (3, cAAC=cyclic (alkyl)(amino) carbene). The calculations predict that 1 and 2 have equilibrium geometries where the ligands are bonded with rather acute bonding angles at the linear C3 moiety. The phosphine adduct 1 has a synclinal (gauche) conformation whereas 2 exhibits a trans conformation of the ligands. In contrast, the compound 3 possesses a nearly linear arrangement of the carbene ligands at the C3 fragment. The bond dissociation energies of the ligands have the order 1<2<3. The bonding analysis using charge and energy decomposition methods suggests that 3 is best described as a cumulene with electron‐sharing double bonds between neutral fragments (cAACMe)2 and C3 in the respective electronic quintet state yielding (cAACMe)=C3=(cAACMe). In contrast, 1 and 2 possess electron‐sharing and dative bonds between positively charged ligands [(PPh3)2]+ or [(NHCMe)2]+ and negatively charged [C3]− fragments in the respective doublet state. [ABSTRACT FROM AUTHOR]

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Dimethyl sulfoxide (DMSO) is an aprotic organic solvent widely used in laboratory practice due to its ability to dissolve both polar and nonpolar compounds. However, DMSO is also commonly known as a strongly coordinating solvent, especially towards transition metal containing complexes. In this study, estimation of the coordination ability of DMSO towards the Cu(II) ion was attempted, employing a model system composed of 3′,4′-dihydroxyflavone-Cu(II) complex in the presence of explicit DMSO molecules, using the density functional theory (DFT). Nature of the Cu-DMSO chemical interaction (i.e. Cu-O bonding) was studied within the framework of quantum theory of atoms in molecules (QTAIM). Impact of DMSO coordination on the charge and spin distribution at Cu(II) ion was inspected using Mulliken population and QTAIM analysis. [ABSTRACT FROM AUTHOR]

Heteronuclear alcoholate complexes [M{Al(OiPr)4}2(bipy)] (2‐M, M = Fe, Co, Ni, Cu, Zn) and [M{Al(OcHex)4}2(bipy)] (3‐M, M = Fe, Co, Ni, Zn) are formed by adduct formation of [M{Al(OiPr)4}2] (1‐M, M = Fe, Co, Ni, Cu, Zn) with 2,2'‐bipyridine and transesterification reaction with cHexOAc. According to crystal structure analyses, in 2‐M and 3‐M the central transition metal ion M2+ is coordinated by two chelating Al(OR)4– moieties and one bipyridine ligand in an octahedral arrangement. Treating 1‐Cu with 2,2'‐bipyridine leads to a reduction process, whereat the intermediate [Cu{Al(OiPr)4}(bipy)2][Al(OiPr)4] (4) could be structurally characterized. During conversion of the iso‐propanolate ligands in 1‐Cu to cyclohexanolate ligands, Cu2+ is reduced to Cu+ forming [Cu{Al(OcHex)4}(py)2] (5). UV/Vis‐spectra and results of thermolysis studies by TG/DTA‐MS are reported. [ABSTRACT FROM AUTHOR]

Aqueous reactions of thorium chloride and furanmono‐ and dicarboxylate ligands including 2‐furoate (2FA), 3‐furoate (3FA), and 2,5‐furandicarboxylate (2,5FDC) yielded four Th(IV) phases that exhibit diverse structural chemistry ranging from isolated molecular units to 3D topologies. [Th(2FA)4]n (Th‐1) and [Th(3FA)4]n (Th‐2) consist of isostructural ligand bridged 1D chains. The compounds exhibit wide stability, forming at temperatures of 20–120 °C and pH ca. 1–4. Using the bifunctional ligand 2,5FDC a stark difference is observed; Th2(2,5FDC)4(H2O)10·2H2O (Th‐3) is built from relatively rare ligand‐bridged molecular complexes. Th‐3 similarly exhibits broad synthetic stability, forming over 20–100 °C and pH 1.8–6. At higher temperatures; however, [Th(2,5FDC)2(H2O)2]n (Th‐4), which adopts an extended 3D network is observed. The structures were determined by single‐crystal X‐ray diffraction and further characterized via Raman and IR spectroscopy as well as thermogravimetric analysis. Overall, the work highlights the role of organic ligands in the stabilization of unique Th structural units. [ABSTRACT FROM AUTHOR]

Lanthanide triflates have been used to incorporate NdIII and SmIII ions into the 2.2.2‐cryptand ligand (crypt) to explore their reductive chemistry. The Ln(OTf)3 complexes (Ln=Nd, Sm; OTf=SO3CF3) react with crypt in THF to form the THF‐soluble complexes [LnIII(crypt)(OTf)2][OTf] with two triflates bound to the metal encapsulated in the crypt. Reduction of these LnIII‐in‐crypt complexes using KC8 in THF forms the neutral LnII‐in‐crypt triflate complexes [LnII(crypt)(OTf)2]. DFT calculations on [NdII(crypt)]2+], the first NdII cryptand complex, assign a 4f4 electron configuration to this ion. [ABSTRACT FROM AUTHOR]

Herein we report the synthesis of a new P‐chirogenic triazole‐based phosphine according to the ephedrine methodology. Upon reaction with late transition‐metal derivatives, RhI and PdII, phosphine‐triazole forms complexes with bidentate P,N coordination, as demonstrated by spectroscopic and X‐ray crystallographic analyses. First experiments in asymmetric catalysis showed the catalytic potential of this new chiral P,N‐type ligand. [ABSTRACT FROM AUTHOR]

We recently reported dipyridinosilole (DPyS) and dipyridinogermole (DPyG) as π‐conjugated units that show low‐temperature phosphorescence. A copper complex of DPG shows solid‐state phosphorescence at room temperature. In this work, we prepared diphenyldipyridinostannole (DPySn1). Its optical and electrochemical properties were investigated and compared with those of DPyS1 and DPyG1 with the same phenyl substituents. DPySn1 showed the most red‐shifted phosphorescence at 520 nm at 77 K in the solid‐state, which is likely due to the intermolecular Sn‐pyridine interaction that was confirmed by single‐crystal X‐ray diffraction. Copper complexes of DPyS1 and DPySn1 were also prepared and it was found that the phosphorescence of these dipyridinometallole‐copper complex solids was red‐shifted in the order of DPySn1−Cu (617 nm)

A conspicuous detail of the so‐called brown‐ring test (the analytical test on nitrate) is the reddish color of the bottom layer of concentrated sulfuric acid, which develops upon the bleeding of the brown layer into the acid. Crystals of the same color form from a solution of ferrous sulfate in concentrated sulfuric acid on saturation with gaseous nitric oxide. The structure of this H3O[{Fe(NO)(μ4‐SO4)(μ2‐SO4)0.5}n/n] (1a) is made up from infinite chessboard‐type layers with sulfur on the field junctions and Fe(NO) moieties below the black and above the white fields. An Fe–N–O angle of about 160° causes disorder in the tetragonal space group I4/mmm. A similar crystal pathology was found in the related [{Fe(MeOH)(NO)(μ4‐SO4)}n/n] (1b) in the same crystal class. A one‐dimensional coordination polymer is formed in crystals of a third compound that comprises the Fe(NO)O5 coordination pattern, namely the brown oxalato species [{Fe(H2O)(NO)(μ2‐ox)}n/n·H2O] (2). A still larger NO tilt of about 156° is not obscured by disorder in the triclinic crystals of 2. [ABSTRACT FROM AUTHOR]

The tridentate dpmp ligand was reacted with CuI salt and cyano ligand affording selectively and unexpectedly the polymetallic Cu11 complex 2 along one‐step reaction. The formation of this derivative 2 can be explained by self‐assembling processes controlled by adaptive coordination‐driven supramolecular chemistry. The solid‐state photophysical behavior of 2 was studied suggesting TADF properties. [ABSTRACT FROM AUTHOR]

The reactions of the phosphinoborane Ph2PBH2·NMe3 with Cu(I) halides [CuCl, CuBr, CuI] and [Cu(CH3CN)4BF4], respectively, were studied. Depending on the ratio of the reactants used, the former reaction allowed for the synthesis of eight neutral coordination compounds with the general formula [CunXn(Ph2PBH2·NMe3)m] (X = Cl, Br, I; n = 1, 2, 4, 5; m = 2, 4) (4–11). The latter reaction, however, led to the formation of the homoleptic complex [Cu(Ph2PBH2·NMe3)3][BF4] (13). The structures of the products 4–11 and 13 were compared to related complexes possessing the well‐known Ph3P ligand. All compounds were characterized by single crystal X‐ray structure analysis, multinuclear NMR spectroscopy, IR spectroscopy and mass spectrometry. [ABSTRACT FROM AUTHOR]

We report the triply bridging coordination of thiophene and selenophene to a trinuclear metal cluster site. The triply bridging coordination of selenophene at a Pd3 site forms a unique spiro‐type Pd5 cluster. Furthermore, either thiophene or selenophene is accommodated stably at a Pd3 site supported by a backside μ3‐cyclooctatetraene ligand through the face‐capping μ3‐coordination. The Pd3 site supported by the cyclooctatetraene ligand showed higher binding affinity of benzene over thiophene, although a Pd2 site strongly favors thiophene over benzene. [ABSTRACT FROM AUTHOR]

Depending on the reaction conditions, the enantiopure macrocycle H3L containing three phenolic units is able to form mono‐ and trinuclear coordination compounds with rare earth metal ions. In these complexes this macrocycle can act as protonated H4L+, neutral H3L, monodeprotonated H2L–, bis‐deprotonated HL2– or tris‐deprotonated L3– ligand. X‐ray crystal structure of the Y(III) derivative of the protonated macrocycle shows highly folded conformation of the ligand with N2O3 set of donor atoms, while the structure of the Y(III) complex of the monodeprotonated macrocycle shows more regular helically twisted conformation of the ligand. Under basic conditions trinuclear complexes of the type [M3L(OH)2] are formed with most of rare earth ions, where the macrocycle acts as N6O3 ligand. This type of complex is not formed for the La(III) and Ce(III) ions of the largest radii within the lanthanide(III) series, instead trinuclear complexes of the type [M3L2] are formed. The X‐ray crystal structures of La(III) complex with fully deprotonated or bis‐deprotonated macrocycles indicate that each macrocyclic unit binds only two metal ions, while one of them is shared by two macrocycles. [ABSTRACT FROM AUTHOR]

The coordination behavior of the tridentate alkoxy ligand 6,6'-(((2-hydroxyethyl)azanediyl)bis(methylene)) bis(2,4-di-tert-butylphenol) (termed H3-AM-DBP2) with group 4 metal alkoxides ([M(OR)4]) in a 1:1 ratio was previously found to generate [(ONep)Ti(κ 4 (O,O',O",N)-AM-DBP2)] and [(OR)Zr(κ4 (μ-O,O',O",N)-AM-DBP2)]2 (M = Zr, Hf). Additional studies revealed that increasing the stoichiometric ratio to 1:2 H3-AM-DBP2:[M(OR)4] led to the isolation of [(ONep)Ti(κ4 (μ-O,O',O",N)-AM-DBP2)(μ-ONep)Ti(ONep)3] (1)•tol, [(OBu t)Zr(κ4 (μ-O,O',O",N)-AM-DBP2)(μ-OBu t)Zr(OBu t)3] (2) and [(OBu t)Hf(κ4 (μ-O,O',O",N)-AM-DBP2)(μ-OBu t)Hf(OBu t)3] (3). The asymmetric dinuclear complexes of 1-3 resemble the chelation of a [M(OR)4] moiety to a "(OR)M(κ4 (O,O',O",N)-AM-DBP2)" fragment. The metal complexed by the AM-DBP2 ligand has a pseudo octahedral geometry while the other metal adopts an intermediate trigonal bipyramidal (TBP-5)/square base pyramidal (SBP-5) geometry for 1 but a distorted SBP-5 for both 2 and 3. The structure and properties of 1-3 were analyzed by computational modeling and fully characterized by standard analytical methods. [ABSTRACT FROM AUTHOR]

Applying quantum chemical calculations, the most likely conformations of the anionic complex species dodecabenzylbambus[6]uril–PF6−, dodecabenzylbambus[6]uril–AsF6−, and dodecabenzylbambus[6]uril–SbF6− were found. In all these complexes, the considered anions, incorporated in the ligand cavity, are bound by hydrogen bonds between methine hydrogen atoms on the convex face of glycoluril units of the dodecabenzylbambus[6]uril ligand and fluorine atoms of the respective "central" anion. Moreover, the interaction energies of the investigated three anionic complexes were calculated. The absolute values of these calculated energies increase in the series of SbF6− < AsF6− < PF6−. [ABSTRACT FROM AUTHOR]

We present here the design and preparation of several discrete coordination complexes exhibiting two Cu(II) ions separated by a dithienylcyclopentene as a photoswitchable spacer, proposed as models of molecular √SWAP quantum gates. These models use the two Cu(II) ions as realizations of qubits and the spacer as a light switch intended to trigger the gate by reversibly undergoing a ring closing isomerization. For this, a dicarboxylate species with a central diarylethene, H2L1, has been used, together with bipyridine or phenantroline as capping ligands. Also, a new dinucleating ligand containing the photoactive moiety between two tridentate coordinating pockets, H4L2, has been designed and prepared for the same purpose. The four complexes have been characterized by single‐crystal X‐ray diffraction. Three of them exhibit reversible photoswitching in solution. [ABSTRACT FROM AUTHOR]

Keywords: coordination chemistry; DFT calculations; di-pi-methane rearrangement; phosphabarrelene; phosphorus ligands This P,N-hybrid ligand readily forms coordination compounds with Rh SP I sp , W SP 0 sp , and Fe SP 0 sp and undergoes a rather selective photochemical di- -methane rearrangement in the coordination sphere of the metal center to afford a novel 5-phosphasemibullvalene derivative. Coordination chemistry, DFT calculations, di-pi-methane rearrangement, phosphabarrelene, phosphorus ligands. [Extracted from the article]

The separation of rare‐earth ions from one another is challenging due to their chemical and physical similarities. Nearly all rare‐earth separations rely upon small changes in ionic radii to direct speciation or reactivity. Herein, we show that the intrinsic magnetic properties of the rare‐earth ions impact the separations of light/heavy and selected heavy/heavy binary mixtures. Using TriNOx3− ([{(2‐tBuNO)C6H4CH2}3N]3−) rare‐earth complexes, we efficiently and selectively crystallized heavy rare earths (Tb–Yb) from a mixture with light rare earths (La and Nd) in the presence of an external Fe14Nd2B magnet, concomitant with the introduction of a concentration gradient (decrease in temperature). The optimal separation was observed for an equimolar mixture of La:Dy, which gave an enrichment factor of EFLa:Dy=297±31 for the solid fraction, compared to EFLa:Dy=159±22 in the absence of the field, and achieving a 99.7 % pure Dy sample in one step. These results indicate that the application of a magnetic field can improve performance in a molecular separation system for paramagnetic rare‐earth cations. [ABSTRACT FROM AUTHOR]

The calculations of bimetallic complexes of the type (X)[(Ind)M2(L)2] (M = Ni, Pd, L = CO, (PEt3) and X = Allyl, Cp and indenyl) have been done using two DFT functionals, namely BP86 and B3LYP*. The allyl, Cp and indenyl ligands adopt the same η3-coordination mode with a π bond and can be considered to be isolobal, while the chloride acts as σ- and π-donor. The computed structural and energetic parameters and energy decomposition yield chemically useful information. We report that the metal–metal bond distances are slightly sensitive to the electron donation and electron π-backdonation as the isolobal prediction suggests. Changing the metal from Ni to Pd has the result of increasing the metal–metal bond distance, decreasing the natural population of Pd and the weakness interactions between the X− ligand and the [(Ind)M2(L)2]+ fragment. The results showed that the four ligands behave quite similarly in terms of bonding, coordination mode and donation and π-backdonation properties highlighted by the orbitals' populations and the energy decomposition. However, the strength of interactions can be classified as follows: Cl < Cp ≈ Ind < Allyl. In all the complexes studied, the M22+ moiety adopts a single metal–metal bonding attributing the 16-MVE configuration to each M(I) cation. [ABSTRACT FROM AUTHOR]

We describe herein the synthesis of 2,6‐bis(pyrazol‐1‐yl)pyridine (1‐bpp) ligands substituted by helicene units in the 4‐position of the pyridine ring. The two‐step procedure afforded the molecules bpp[n]helicene (n = 4, 5 and 6) and methyl‐bpp[4]helicene, abbreviated as 4, 5, 6 and 4m respectively, with overall good yields. This series of ligands shows fluorescence in the violet region, with a red shift of the emission when increasing the number of aromatic rings in the helicene unit. The tridentate fluorophores have been reacted with Re(CO)5Cl and [Ru(terpy)Cl3] to prepare a series of transition metal complexes formulated as [ReI(n)(CO)3Cl] (n = 4 and 5) and [RuII(n)(terpy)](PF6)2 (n = 4, 4m, 5 and 6). The compounds [ReI(4)(CO)3Cl]·(CH2Cl2)0.5(H2O) and [RuII(4m)(terpy)](PF6)2 crystallized in the centrosymmetric space groups P21/n and P1 respectively, and thus present both M and P helicene units in their crystal structures. The absorption and emission properties of the complexes have been studied. All complexes show luminescence at 77 K in frozen DCM solution. The tricarbonyl complex [ReI(5)(CO)3Cl] shows a strong emission band with two peaks at 540 nm and 580 nm, which could be attributed to ligand‐localized π–π* phosphorescence due to the extended π system of the ligand. The heteroleptic RuII complexes show emission bands above 600 nm attributed to the terpyridine‐based 3MLCT state. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) coated with whey peptides are shown to be a useful optical nanoprobe for the highly sensitive determination of Pd(II). The peptidic surface of the AgNPs works as a molecular receptor for the rapid detection of Pd(II) via a color change from dark yellow to orange/red along with a spectral red-shift with a gap about 120 nm. The effect is caused by the formation of a coordination complex between Pd(II) and the peptide ligands. This results in the aggregation of AgNPs and an absorbance spectral shift from 410 to 530 nm. The absorbance response is linear in the range 0.1 to 1.3 μM Pd(II) with a low detection limit of 115 nM. The nanoprobe responds within a few minutes and is not interfered by other metal ions except for Mg(II). The probe potentially can be applied to the determination of Pd(II) contamination in the products of Pd(II)−catalyzed organic reactions and in pharmaceutical settings. [ABSTRACT FROM AUTHOR]

Reactions of [Mn(H2dapsc)Cl2]⋅H2O (dapsc=2,6‐ diacetylpyridine bis(semicarbazone)) with K3[Fe(CN)6] and (PPh4)3[Fe(CN)6] lead to the formation of the chain polymeric complex {[Mn(H2dapsc)][Fe(CN)6][K(H2O)3.5]}n⋅1.5n H2O (1) and the discrete pentanuclear complex {[Mn(H2dapsc)]3[Fe(CN)6]2(H2O)2}⋅4 CH3OH⋅3.4 H2O (2), respectively. In the crystal structure of 1 the high‐spin [MnII(H2dapsc)]2+ cations and low‐spin hexacyanoferrate(III) anions are assembled into alternating heterometallic cyano‐bridged chains. The K+ ions are located between the chains and are coordinated by oxygen atoms of the H2dapsc ligand and water molecules. The magnetic structure of 1 is built from ferrimagnetic chains, which are antiferromagnetically coupled. The complex exhibits metamagnetism and frequency‐dependent ac magnetic susceptibility, indicating single‐chain magnetic behavior with a Mydosh‐parameter φ=0.12 and an effective energy barrier (Ueff/kB) of 36.0 K with τ0=2.34×10−11 s for the spin relaxation. Detailed theoretical analysis showed highly anisotropic intra‐chain spin coupling between [FeIII(CN)6]3− and [MnII(H2dapsc)]2+ units resulting from orbital degeneracy and unquenched orbital momentum of [FeIII(CN)6]3− complexes. The origin of the metamagnetic transition is discussed in terms of strong magnetic anisotropy and weak AF interchain spin coupling. [ABSTRACT FROM AUTHOR]

The [4+2] cycloaddition of 2‐(2′‐pyridyl)‐4,6‐diphenyl‐λ3‐phosphinine with the highly reactive dienophile hexafluoro‐2‐butyne has been studied and the first pyridyl‐functionalized 1‐phosphabarrelene was obtained and structurally characterized. Although monodentate CF3‐1‐phosphabarrelenes show only a poor coordination ability, the chelating nature of the novel P,N‐hybrid ligand gives access to various transition‐metal complexes. Upon irradiation with UV light, the pyridyl‐functionalized 1‐phosphabarrelene undergoes a rather selective di‐π‐methane rearrangement in the coordination sphere of the metal center, leading to the formation of a complex based on a hitherto unknown pyridyl‐functionalized 5‐phosphasemibullvalene derivative. DFT calculations provide first insights into the mechanism of this reaction. [ABSTRACT FROM AUTHOR]

Building upon previous work, the chemistry of [(η6‐p‐cymene)Ru{P(OMe)2OR}Cl2], (R=H or Me) has been extended with [H2B(mbz)2]− (mbz=2‐mercaptobenzothiazolyl) using different Ru precursors and borate ligands. As a result, a series of 1,3‐N,S‐chelated ruthenium borate complexes, for example, [(κ2‐N,S‐L)PR3Ru{κ3‐H,S,S'−H2B(L)2}], (2 a–d and 2 a'–d'; R=Ph, Cy, OMe or OPh and L=C5H4NS or C7H4NS2) and [Ru{κ3‐H,S,S'‐H2B(L)2}2], (3: L=C5H4NS, 3': L=C7H4NS2) were isolated upon treatment of [(η6‐p‐cymene)RuCl2PR3], 1 a–d (R=Ph, Cy, OMe or OPh) with [H2B(mp)2]− or [H2B(mbz)2]− ligands (mp=2‐mercaptopyridyl). All the Ru borate complexes, 2 a–d and 2 a'–d' are stabilized by phosphine/phosphite and hemilabile N,S‐chelating ligands. Treatment of these Ru borate species, 2 a'–c' with various terminal alkynes yielded two different types of five‐membered ruthenacycle species, namely [PR3{C7H4S2‐(E)‐N‐C=CH(R')}Ru{κ3‐H,S,S'−H2B(L)2}], (4–4'; R=Ph and R'=CO2Me or C6H4NO2; L=C7H4NS2) and [PR3{C7H4NS‐(E)‐S‐C=CH(R')}Ru{κ3‐H,S,S'−H2B(L)2}], (5–5', 6 and 7; R=Ph, Cy or OMe and R'=CO2Me or C6H4NO2; L=C7H4NS2). All these five‐membered ruthenacycle species contain an exocyclic C=C moiety, presumably formed by the insertion of a terminal alkyne into the Ru−N and Ru−S bonds. The new species have been characterized spectroscopically and the structures were further confirmed by single‐crystal X‐ray diffraction analysis. Theoretical studies and chemical‐bonding analyses established that charge transfer occurs from phosphorus to ruthenium center following the trend PCy3

The synthesis of two well‐defined rhodium(I) complexes of nitrous oxide (N2O) is reported. These normally elusive adducts are stable in the solid state and persist in solution at ambient temperature, enabling comprehensive structural interrogation by 15N NMR and IR spectroscopy, and single‐crystal X‐ray diffraction. These methods evidence coordination of N2O through the terminal nitrogen atom in a linear fashion and are supplemented by a computational energy decomposition analysis, which provides further insights into the nature of the Rh–N2O interaction. [ABSTRACT FROM AUTHOR]

We report the synthesis, characterization, solid‐state structure and solution behavior of simple lanthanide trifluoromethanesulfonate complexes supported by a hexadentate tetrakis(2‐pyridylmethyl)ethylenediamine ligand. The complexes' solid‐state structures exhibit different trifluoromethanesulfonate coordination, correlating with the size difference of the lanthanide ions. The ligand is capable of sensitizing Nd, Sm, Eu, Tb, Dy, and Yb yielding metal‐centered emission with moderate quantum yields. [ABSTRACT FROM AUTHOR]

The merging of small‐scale syntheses and rapid crystallization methods have provided access to crystalline samples of berkelium (Z=97) and californium (Z=98) coordination complexes and compounds that can be interrogated with a suite of spectroscopic tools and structural elucidation approaches that have come online over the last 20 years. The combination of this experimental data with relativistic theoretical methods that capture the effects of spin‐orbit coupling and scalar relativistic effects have allowed us to understand the electronic structure of berkelium and californium compounds at a level of detail that was not previously possible. The harbinger of this new era of post‐curium chemistry was the synthesis and characterization of [Cf{B6O8(OH)5}]. This compound possesses a structure type that is distinct from earlier actinide borates, a reduction in coordination number for californium, contracted Cf−O bond lengths, a substantially reduced magnetic moment with respect to the calculated free‐ion moment and, most importantly, vibronically coupled broadband photoluminescence. Ligand‐field analysis also showed that the splitting of the ground state was larger than typically found in the f‐block elements, and when taken together places its overall electronic structure as a hybrid of d‐ and f‐block components. The discovery of the unusual properties of this compound has led to the development of large families of 4f and 5f coordination complexes, in an effort to uncover the underlying origin of the electronic structure oddities, and whether there really is a sharp onset of these changes at californium. This in turn pushed the development of far more challenging berkelium chemistry (from a radiologic standpoint) because the half‐life of the isotopes decreases from 351 years for 249Cf to 330 days for 249Bk. This short review details some of the chemistry that has been reported over the last 15 years, and its consequences for understanding the periodic table. [ABSTRACT FROM AUTHOR]

Crystal structures of a series of organic–inorganic hybrid gold iodide perovskites, formulated as A2[AuII2][AuIIII4] [A=methylammonium (MA) (1) and formamidinium (FA) (2)], A′2[I3]1−x[AuII2]x[AuIIII4] [A′=imidazolium (IMD) (3), guanidinium (GUA) (4), dimethylammonium (DMA) (5), pyridinium (PY) (6), and piperizinium (PIP) (7)], systematically changed depending on the cation size. In addition, triiodide (I3−) ions were partly incorporated into the AuI2− sites of 3–7, whereas they were not incorporated into those of 1 and 2. Such a difference comes from the size of the organic cation. Optical absorption spectra showed characteristic intervalence charge‐transfer bands from AuI to AuIII species, and the optical band gap increased as the size of the cation became larger. [ABSTRACT FROM AUTHOR]

Although the "brown‐ring" ion, [Fe(H2O)5(NO)]2+ (1), has been a research target for more than a century, this poorly stable species had never been isolated. We now report on the synthesis of crystals of a salt of 1 which allowed us to tackle the unique bonding situation on an experimental basis. As a result of the bonding analysis, two stretched, spin‐polarised π‐interactions provide the Fe–NO binding—and challenge the concept of "oxidation state". [ABSTRACT FROM AUTHOR]

Reaction of a tethered triamine ligand with Bi(NMe2)3 gives a Bi triamide, for which a BiI electronic structure is shown to be most appropriate. The T‐shaped geometry at bismuth provides the first structural model for edge inversion in bismuthines and the only example of a planar geometry for pnictogen triamides. Analogous phosphorus compounds exhibit a distorted pyramidal geometry because of different Bi−N and P−N bond polarities. Although considerable BiI character is indicated for the title Bi triamide, it exhibits reactivity similar to BiIII electrophiles, and expresses either a vacant or a filled p orbital at Bi, as evidenced by coordination of either pyridine N‐oxide or W(CO)5. The product of the former shows evidence of coordination‐induced oxidation state change at bismuth. [ABSTRACT FROM AUTHOR]

Arginine and copper(II) play an important role in human physiology. Arginine is a precursor of NO which is a vasodilator and the right quantity of copper(II), bound to several amino acids, is necessary for the human body. The complex formation between copper(II) and arginine is studied at 25 °C and in two different ionic media: 1.00 mol dm−3 NaClO4 and 1.00 mol dm−3 NaCl. The investigation is carried out potentiometrically, by employing in 1.00 mol dm−3 NaClO4 cells involving glass and copper amalgam electrodes. In 1.00 mol dm−3 NaCl, only the glass electrode can be used. In both ionic media, the adoption of the constant ionic medium allows to extend the investigation to a large range of reagent concentration. Experimental data can be explained by assuming the formation of mononuclear complexes in copper(II). In 1.00 mol dm−3 NaClO4, complexes with the participation of hydrogen ions are assumed. The presence of the main complex in a large hydrogen ion concentration is supported also by spectrophotometric measurements. [ABSTRACT FROM AUTHOR]

Phytate (L12−) is a relevant natural product. It interacts strongly with biologically relevant cations, due to the high negative charge exhibited in a wide pH range. The synthesis and crystal structures of the mixed‐ligand Cu(II) polynuclear complexes K(H2tptz)0.5[Cu(H8L)(tptz)] ⋅ 3.6H2O (1), K(H2O)3{[Cu(H2O)(bpca)]3(H8L)} ⋅ 1.75H2O (2), and K1.5(H2O)2[Cu(bpca)](H9.5L) ⋅ 8H2O (3) (tptz=2,4,6‐tri(pyridin‐2‐yl)‐1,3,5‐triazine; Hbpca=bis(2‐pyridylcarbonyl) amine) are reported herein. They were obtained by the use of an aromatic rigid amine, which satisfies some of the metal coordination sites and promotes the hierarchical assembly of 2D polymeric structures. Speciation of phytate−Cu(II)−Hbpca system and determination of complex stability constants were performed by means of potentiometric titrations, in 0.15 M NMe4Cl at 37.0 °C, showing that, even in solution, this system is able to produce highly aggregated complexes, such as [Cu3(bpca)3(H7L)]2−. Furthermore, the Cu(II)‐mediated tptz hydrolysis was studied by UV‐vis spectroscopy at room temperature in 0.15 M NMe4Cl. Based on the equilibrium results and with the aid of molecular modelling tools, a plausible self‐assembly process for 2 and 3 could be proposed. [ABSTRACT FROM AUTHOR]

A new tripodal ligand, based on a central nitrogen atom tris‐functionalized with 6‐methylene‐2‐pyridyl phosphonic acid was synthesized and characterized, in particular by its X‐ray crystal structure. The coordination behaviour of the tripod with lanthanide cations in aqueous solutions was studied by means of UV/Vis electronic absorption spectroscopy and steady‐state and time‐resolved luminescence spectroscopy, revealing the formation of a [LnL] complex followed by polynuclear species with 2:1 and 3:1 metal/ligand stoichiometries. The [LnL] complexes (Ln = Eu, Tb and Yb) were isolated and characterized and the solid‐state structure of the Eu complex was determined by X‐ray diffraction analysis on monocrystals, revealing the observation of dimeric species, in which the Ln3+ cations are firmly held in the cavity formed by the three pyridylphosphonate arms, the coordination of the cations being completed by a water molecule and a phosphonate function of the second complex, allowing for the formation of the dimers, which are further stabilized by π–π stacking interactions between one pyridyl unit of each adjacent monomer. The spectroscopic properties of the complexes in aqueous solutions were studied, showing an impressive 16 µs excited state lifetime for the Yb complex in D2O, despite the presence of a water molecule in the first coordination sphere. [ABSTRACT FROM AUTHOR]

Platinum diimine dithiolene complexes bearing mesogenic groups on one or both ligands have been prepared through an original ligand metathesis reaction to introduce the dithiolene ligand. The neutral diimine ligands, the intermediate platinum dichloride diimine complexes, and the target compounds were characterized by a combination of electronic (electrochemistry, absorption and emission spectroscopy, DFT calculations) and structural (SAXS, DSC) tools. Several novel liquid crystalline platinum diimine‐dithiolene were identified over a large temperature range, and the systems were endowed with ambipolar properties, associated with the high reversibility of both oxidation and reduction processes. [ABSTRACT FROM AUTHOR]

For ethene derivatives with large groups the cis‐isomer is often quite unstable and unavailable. Herein, we report an exception of two stable coordination complexes, (cis‐L)ZnCl2, starting from trans‐1,2‐bis(1‐R‐benzo[d]imidazol‐2‐yl)ethene (R=H, L1; R=CH3, L2) ligands under solvothermal condition (T ≥140 °C). Using the intensity of the absorption and luminescence spectra as probes we proposed its progressive cis‐to‐trans reversal upon irradiation with UV light, which was confirmed by powder X‐ray diffraction (PXRD). Similar results observed in the series of (cis‐L2)MIICl2 [M=Fe (4), Co (5), Ni (6)] demonstrate the universal strategy. The results of PXRD, NMR spectroscopy, ESI‐MS and DFT calculations support the above conclusion. NMR spectroscopy indicates that irradiation of 1 converts an optimized 71 % of the cis‐isomer to trans, whereas the free trans‐L1 ligand transforms to only 15 % cis‐isomer under similar conditions. Switch controller: Thermal treatment at 140 °C of trans‐L in the presence of MIICl2 (M=Fe, Co, Ni, Zn) led to stable (cis‐L)MCl2 and photoexcitation of the latter caused its transformation back to (trans‐L)MCl2(solvent). The kinetics can be followed by using UV/Vis absorption and luminescence. The results were confirmed by ESI‐MS, NMR spectroscopy, powder X‐ray diffraction and DFT calculations. [ABSTRACT FROM AUTHOR]

The coordination chemistry of 2‐(2′‐pyridyl)‐4,6‐diarylphosphinines towards ReI has been investigated and compared to the structurally analogous 2,2′‐bipyridine derivatives. The different steric properties of the chelating pyridylphosphinines with respect to substituted bipyridines lead to considerable differences in the structures of the mononuclear [(P^N)Re(CO)3X] and [(N^N)Re(CO)3X] (X = Cl, Br) complexes, both in the solid state and in solution. The phosphinine‐based coordination compounds are highly sensitive towards nucleophilic attack and react reversibly with water at the P=C double bond. The coordination chemistry of 2‐(2′‐pyridyl)‐4,6‐diarylphosphinines towards ReI was investigated and compared to the related 2,2′‐bipyridine derivatives. The coordination compounds show significant structural differences, both in the solid state and in solution. The phosphinine‐based ReI complexes are highly sensitive towards nucleophilic attack and react reversibly with water at the P=C‐double bond. [ABSTRACT FROM AUTHOR]

By reacting P4Se3 and As4S3 with Ag[Al(ORF)4] {–RF = –C(CF3)3 or –hfip [= –C(H)(CF3)2]} in suitable solvents, Ag(P4Se3)[Al(Ohfip)4] (1), Ag(P4Se3)2[Al(ORF)4] (2), Ag(P4Se3)3[Al(ORF)4] (3), Ag2(As4S3)3[Al(ORF)4]2 (4) and Ag(As4S3)2[Al(ORF)4] (5) were synthesized and characterized by SC‐XRD, Mass spectrometry, Raman spectroscopy as well as solution NMR spectroscopy. When using stronger coordinating anions, only P4Se3 forms an isolable complex yielding 1 featuring a [Ag2(P4Se3)2]2+ core capped by anions acting as the first example of P4Se3 coordinating through selenium atoms. Upon using the weakly coordinating anion [Al{OC(CF3)3}4]–, the dimeric complexes 2 and 4 are accessible in dichloromethane or ortho‐difluorobenzene (o‐dfb), respectively. Complex 2 shows isolated [Ag2(P4Se3)4(CH2Cl2)2]2+ dications with a [Ag2(P4Se3)2]2+ core similar to 1. Complex 4 shows isolated [Ag2(As4S3)3]2+ dications featuring a weak argentophilic contact. All of these complexes include solvent molecules or anions in the coordination sphere of the metal. When switching to the polar yet non‐coordinating solvent SO2, the coordination spheres are filled with additional ligands and compounds 3 and 5 form. Complex 3 shows condensed [Ag(P4Se3)3]+ units yielding a one dimensional chain and represents the first homoleptic metal(P4Se3) complex. Complex 5 shows a similar paddle wheel structure as in 4 with interconnecting As4S3 ligands and is the first known example of a homoleptic metal(As4S3) complex. To be or not to be coordinated, that is the question investigated by the study of the coordination behavior of the weakly basic cage molecules P4Se3 and As4S3. Using suitable Ag[WCA] salts and the polar yet non‐coordinating solvent SO2 made it possible to characterize the homoleptic complexes of these ligands, whereas stronger coordinating anions or solvents such as CH2Cl2 and ortho‐difluorobenzene yield dimeric structures displaying new coordination modes. [ABSTRACT FROM AUTHOR]

The synthesis of a new imide type anion, methylcarbonate(trifluoromethylsulfonyl)imide (MCTFSI) is described and the physicochemical properties of its sodium and N‐butyl‐N‐methyl pyrrolidinium salts as well as structural information obtained by X‐ray diffraction studies of the sodium salt are discussed in terms of charge delocalisation, coordination chemistry and electrochemical behaviour with respect to the analogous imdides bis(trifluoromethanesulfonyl)imide (TFSI) and bis(fluorosulfonyl)imide (FSI). The insight obtained from studying the new anion informs and reemphasizes the concept of weakly coordinating anions and coordination chemistry in designing electrolyte salts. The better half: A hybrid imide anion consisting of a trifluorosulfonyl and a methylcarbonate group shows a unique coordination behaviour. Owing to the combination of electron‐withdrawing groups the new anion is less weakly coordinating than the symmetric TFSI salt. Reversible Na deposition and stripping was established in ethylene carbonate:propylene carbonate (EC:PC) electrolyte. [ABSTRACT FROM AUTHOR]

This essay highlights the role of single and multiple reversible self‐sorting events for the development of responsive multi‐component structures as well as multi‐state transformations, devices and machinery. Recent examples illustrate how distinct molecular devices are spatiotemporarily interconnected by chemical signaling to act as integrated machinery and highlight the enormous potential of molecular cybernetics. [ABSTRACT FROM AUTHOR]

Two tetranuclear compounds [Ln4Na(μ4‐OH)(TC4A)2(acac)4] [Ln = Tb (1), Eu (2)] (acac = acetylacetonate) were synthesized and characterized based on p‐tert‐butylthiacalix[4]arene (H4TC4A). Compounds 1 and 2 are isostructural and crystallize in the monoclinic C2/c space group. There are two crystallographically independent metal atoms in one asymmetric unit. Ln1, Ln2, and two metal atoms generated by the symmetry operation are bridged by one μ4‐OH group to form a planar tetragonal Ln4(μ4‐OH) unit. Each Ln4(μ4‐OH) unit is surrounded by four acac anions and two disordered sodium ions in the planar direction. The upper and lower positions of the Ln4(μ4‐OH) unit are further coordinated by two cone‐shaped TC4A ligands to form a sandwich‐type molecular structure. Luminescent measurements reveal that both compounds 1 and 2 exhibit good photoluminescent properties. Moreover, the static and dynamic magnetic properties of compound 1 were also investigated, which demonstrates that 1 is one functional material candidate combining luminescent and antiferromagnetic properties in one molecule. [ABSTRACT FROM AUTHOR]

This contribution covers the preparation and characterization of 2,2‐bis(5‐tetrazolyl)propane (5‐DTP) (1). The bridged bitetrazole is used as a neutral nitrogen‐rich ligand in 3d transition metal(II) based complexes for the first time and can be synthesized via [2+3] cycloaddition from sodium azide and dimethylmalononitrile. The combination with different anions (e.g., perchlorate, nitrate, sulfate, and chloride) yields materials with widely varying physicochemical properties. The obtained coordination compounds were characterized using low‐temperature single‐crystal X‐ray diffraction (except 14), IR spectroscopy, elemental analysis, and DTA (except 16). The sensitivities toward external stimuli (impact and friction) were determined according to the Bundesamt für Materialforschung und ‐prüfung (BAM) standard methods together with its sensitivities against electrostatic discharge (except 16). Complexes 10 and 14 were characterized in laser ignition experiments. For determination of the compounds' deflagration to detonation transition (DDT) capability, hot plate and hot needle tests were performed for the zinc(II) and copper(II) perchlorate complexes. [ABSTRACT FROM AUTHOR]

The chemistry of phosphorus(III) ligands, which are of key importance in coordination chemistry, organometallic chemistry and catalysis, is dominated by relatively electron‐rich species. Many of the electron‐poor PIII ligands that are readily available have relatively small steric profiles. As such, there is a significant gap in "ligand space" where more sterically bulky, electron‐poor PIII ligands are needed. This contribution discusses the coordination chemistry, steric and electronic properties of PIII ligands bearing highly fluorinated alkoxide groups of the general form PRn(ORF)3−n, where R=Ph, RF=C(H)(CF3)2 and C(CF3)3; n=1–3. These ligands are simple to synthesize and a range of experimental and theoretical methods suggest that their steric and electronic properties can be "tuned" by modification of their substituents, making them excellent candidates for large, electron‐poor ligands. Filling the gaps: A comprehensive overview of the synthesis, stereoelectronic properties and coordination chemistry of large, electron‐poor PIII ligands bearing highly fluorinated alkoxides is described. [ABSTRACT FROM AUTHOR]

Small unsaturated phosphacycles are versatile reagents owing to their strain and the added functionality of the double bond and the phosphorus lone pair. Herein we report the synthesis and isolation of the smallest possible cyclic phosphasilene as a stable adduct with an N‐heterocyclic carbene (NHC). First reactivity studies show a) that the PSi2 ring is a competent ligand to the Fe(CO)4 fragment via the phosphorus lone pair and b) that the abstraction of the NHC by BPh3 results in the rapid head‐to‐head or head‐to‐tail dimerization of the PSi2 unit. The relatively facile NHC cleavage indicates that the P=Si double bond is available for further manipulation. The smallest cyclic Si=P species: A phosphorus(I) cation was used as a precursor for the synthesis of the first three‐membered cyclic phosphasilene. The highly strained ring compound can be coordinated to a transition metal through the ylidic phosphorus center or "clicked" with itself to give two cluster‐like Si4P2 isomers. [ABSTRACT FROM AUTHOR]