A brief history of scorpionates

Editorial

A tris­(pyrazolyl)borate rhodium phosphite complex that undergoes an Arbusov-like rearrangement

In the presence of difluoromethane in pentane solvent, the scorpionate complex Tp′Rh[P(OMe)₃](Me)H loses methane to give a product in which the phosphine O—Me bond is cleaved.

[Bis(3,5-diiso­propylpyrazol-1-yl-κN²)di­hydroborato](tri­phenylphos­phane-κP)copper(I)

The title triphenylphosphane copper(I) complex, incorporating a bis(3,5-diisopropylpyrazol-1-yl)dihydroborate scorpionate ligand, was characterized by X-ray crystallographic analysis. The electron density of the Cu^I ion is discussed and compared to a series of analogous triphenylphosphane complexes.

Improved syntheses, and structural and electronic characterization of carboxamide-substituted Tp^CONHPh,Me and Tp^CONHt-Bu,Me ligands

Improved syntheses and electronic characterization of carboxamide-substituted tris(pyrazol­yl)borate ligands are reported. Their Tl^I salts and the Cu^I carbonyl complexes have been prepared and are compared with alkyl-substituted tris(pyrazolyl)borate ligands.

Tris(pyrazol­yl)methane and 1,8-naph­thal­imide-functionalized dialkynylgold(I) anionic complexes

Complexes of the linear C C—Au—C C unit functionalized with tris­(pyrazol­yl)methane and 1,8-naphthalimide groups have been prepared and structurally characterized.

Thallium(I) complexes of fluorinated bis- and tris­(pyrazolyl)borate ligands: [H₂B{3,5-(CF₃)₂pz}₂]Tl and [HB{3,5-(CF₃)₂pz}₃]Tl

[H₂B{3,5-(CF₃)₂pz}₂]Tl has a two coordinate thallium atom with a bent geometry and boat-shaped bis(pyrazolyl)borate ligand. The related tris(pyrazolyl)borate analogue [HB{3,5-(CF₃)₂pz}₃]Tl has a trigonal pyramidal thallium atom.

Gallium hydride and monovalent indium compounds that feature tris­(pyrazol­yl)hydro­borate ligands

Tris(pyrazolyl)hydroborate ligation has been used to isolate trivalent gallium hydride and monovalent indium complexes, namely {[Tp^But,Me]GaH}[GaCl₄], [Tp^Me₂]In and [Tp^But,Me]In, which have been structurally characterized by single-crystal X-ray diffraction.

Cobalt azide complexes with a tris­(carbene)borate ligand scaffold

One electron oxidation of a four-coordinate tris(carbene)borate cobalt(II) azide complex yields a five-coordinate cobalt(III) bis(azide).

A tris­(pyrazol-1-yl)methane bearing carb­oxy­lic acid groups at position 4: {1-[bis­(4-carb­oxy-3,5-di­methyl-1H-pyrazol-1-yl)meth­yl]-3,5-di­methyl-1H-pyrazole-4-carboxyl­ato}sodium dihydrate

A low-resolution X-ray mol­ecular study shows that the title compound displays scorpionate character, and resolves apparent ambiguities between solution and solid-state NMR spectroscopies.

(N,N-Di­ethyl­dithio­carbamato)[tris­(3,5-di­methyl­pyrazol-1-yl)hydro­borato]copper(II): a new copper(II) di­thio­carbamate compound with the classic Tp^Me₂ scorpionate

This new complex using the classic Tp^Me₂ scorpionate, (Tp^Me₂)Cu(S₂CNEt₂), is relevant to blue copper protein models and to Cu extraction from waste treatment and mine-tailing leachate. The IR and UV–Vis spectra are consistent with the crystal structure.

Heteroscorpionate complexes based on bis­(3,5-di-tert-butyl­pyrazol-1-yl)di­thio­acetate

The heteroscorpionate bis­(3,5-di-tert-butyl­pyrazol-1-yl)di­thio­acetate ligand has been synthesised by reacting bis­(3,5-di-tert-butyl­pyrazol-1-yl)methane with n-BuLi and CS₂. A zinc chloride complex bearing this ligand exhibits κ³N,N′,S-coordination and resembles the active site of zinc-containing peptide de­formyl­ases (PDFs).

{Tris[3-(adamantan-1-yl)-5-iso­propyl­pyrazol-1-yl-κN²]hydro­borato}thallium(I): the scorpionate with the most bulk?

A comparison is made of the thallium(I) complex of the `most hindered' tris­(3-adamantyl-5-iso­propyl­pyrazol-1-yl)hydro­borate ligand and that of the `super-hindered' tris­(7-tert-butyl­indazol-2-yl)hydro­borate ligand

On the (non-)existence of Tutton salts with formula types [M(H₂O)₆](ClO₄)₂(H₂O)₂ and Na₂M(SO₄)₂(H₂O)₆ (M is a first-row transition metal)

Rerefinements based on the original data as well as crystal–chemical considerations make it most likely that the reported Tutton salts with formula types [M(H₂O)₆](ClO₄)₂(H₂O)₂ and Na₂M(SO₄)₂(H₂O)₆ (M is a first row transition metal) do not exist.

The tetra­germanates A₂Ge₄O₉ (A = Na, K and Rb)

The crystal structures of three alkali tetra­germanates A₂Ge₄O₉ (A = Na, K and Rb) are trigonal (space group Pc1). The main building units are a three-membered ring of tetra­hedra, oriented within the (001) plane and forming tetra­hedral sheets. These sheets are connected to each other by two different regular isolated GeO₆ octa­hedra via corner-sharing to build up a tetra­hedral–octa­hedral framework.

Structural reinvestigation of the photoluminescent complex [NdCl₂(H₂O)₆]Cl

The structural study of the title compound is based on low-temperature data and the calculated PDF has been used for local structural analysis. The crystal structure is characterized by a network of [NdCl₂(H₂O)₆]⁺ cations with distorted square-anti­prism geometry, connected by O—H⋯Cl inter­molecular inter­actions.

A one-dimensional coordination polymer of 5-(pyridin-2-yl)-3,3′-bi(4H-1,2,4-triazole) with Cd(NO₃)₂

Single-crystal structural analysis reveals that the title complex is a one-dimensional polymeric chain, which is further extended to a three-dimensional supra­molecular network via a combination of hydrogen-bonding and aromatic stacking inter­actions.

(Acetyl­acetonato-κ²O,O′)(2,2′-bi­pyridine-κ²N,N′)iodido­copper(II): a compound with two mol­ecules in the asymmetric unit due to different π–π inter­actions

The title compound crystallizes in the space group P with Z = 4. The crystal is stabilized by π–π inter­actions and weak C—H⋯I inter­actions. Different inter­molecular inter­actions distinguish the two independent mol­ecules of the asymmetric unit.

Inter­molecular iodine–iodine inter­actions in bis­(pyridine-3-carboxyl­ato)[tetra­kis­(4-iodo­phenyl)­porphyrin­ato]tin(IV) and bis­(pyrimidine-5-carboxyl­ato)[tetra­kis­(4-iodo­phenyl)­porphyrin­ato]tin(IV)

Six-coordinate tin–tetra(4-iodophenyl)porphyrins self-assemble into halogen-bonded tetragonal networks, exhibiting a unique rectangular pattern of interporphyrin I⋯I interactions.

One-dimensional Cu^I and Ag^I ladder-like coordination polymers supported by 2-ethyl-1-(pyridin-3-ylmeth­yl)-1H-benzimidazole

In Cu^I and Ag^I ladder-like coordination polymers, two metal ions are linked by two 2-ethyl-1-(pyridin-3-ylmeth­yl)-1H-benzimidazole ligands (bep) to form a centrosymmetric 18-membered M₂(bep)₂ metallacycle, while adjacent M₂(bep)₂ metallacycles are further inter­linked by another two bep ligands resulting in a ladder-like array.

A three-dimensional polycatenation framework: catena-poly[[di­aqua­bis­(4-{4-[4-(pyridin-4-yl)phen­oxy]phenyl}pyridine)­nickel(II)]-μ₂-naphthalene-2,6-di­carboxyl­ato]

The structure of a nickel compound with a three-dimensional polycatenation framework formed by intermolecular hydrogen bonds and interlocking interactions is reported.

A three-dimensional Cu–Na heteronuclear coordination polymer based on iminodi­acetic acid

In a novel Cu–Na heteronuclear three-dimensional coordination polymer, the carboxyl­ate groups of iminodi­acetate (ida) ligands act as bridges and connect [Cu(ida)] and [Cu(ida)₂] building blocks in a 2:1 ratio, forming two-dimensional arrays. These layers are inter­connected into a three-dimensional structure by sodium ions.

A novel penta­coordinated cadmium compound: catena-poly[benzyl­tri­ethyl­ammonium [[chlorido­cadmate(II)]-di-μ-chlorido]]

The structure of a title novel one-dimensional ABX₃-type organic–inorganic hybrid complex consists of benzyl­tri­ethyl­ammonium cations and one-dimensional anionic {[CdCl₃]⁻}_n chains, in which the Cd^II centres are in an unusual two-layer five-coordinated arrangement.

Mol­ecular cocrystals of 5-(4-bromo­phenyl)-1,3,4-thia­diazol-2-amine: hydrogen bonding in the structures of the 1:1 adduct with 2-(naphthalen-2-yl­oxy)acetic acid and the salt with 3,5-di­nitro­benzoic acid

The cocrystal of 5-(4-bromophenyl)-1,3,4-thiadiazol-2-amine with 2-(naphthalen-2-yloxy)acetic acid is a 1:1 adduct, while with 3,5-dinitrobenzoic acid is a salt. In the adduct, hydrogen bonding gives a one-dimensional chain structure, and in the salt, a discrete centrosymmetric heterotetramer is formed

(E)-3-tert-Butyl-4-(4-chloro­benz­yl)-N-(4-chloro­benzyl­idene)-1-phenyl-1H-pyrazol-5-amine: sheets built from π-stacked hydrogen-bonded dimers

An unexpected but high-yield reaction product forms sheets of π-stacked hydrogen-bonded dimers.

5,5′-Methyl­enebis[6-amino-3-methyl-2-methyl­sulfanylpyrimidin-4(3H)-one]: an unusual mol­ecular geometry within a hydrogen-bonded mol­ecular ribbon

The central C—C—C angle is 120.3 (2)° and the mol­ecules are linked by N—H⋯O hydrogen bonds into a ribbon containing edge-fused S(8) and (8) rings.

Methyl 4-O-β-D-xylo­pyranosyl β-D-manno­pyran­oside, a core disac­charide of an anti­freeze glycolipid

Comparisons are made of the title compound to the inter­nal linkage conformations in the two crystallographic forms of the structurally related disaccharide, methyl β-D-manno­pyranosyl-(1→4)-β-D-xylo­pyran­oside).

A study of the pyramidality index in tris­(2,4,6-triiso­propyl­phen­yl)phos­phonium perchlorate

This is the most sterically congested tri­aryl­phospho­nium salt yet to be reported and has a `propeller' arrangement of the three 2,4,6-triiso­propyl­phenyl groups around the P atom, with the protonation site located along the mol­ecular threefold axis. There are short P⋯H contacts between the flanking isopropyl methine H atoms and the P atom.

A new structure of a serotonin salt: comparison and conformational analysis of all known serotonin complexes

Comparison of the newly determined serotonin salt, serotonin adipate, with previously known salts demonstrates that the conformation of the biologically active component can be modified by altering the counter-ion.

A fused [3.3.0]-neoglycoside lactone derived from glucuronic acid

The crystal structure of bridged neoglycoside, 1-deoxy-1-[(methoxy)methylamino)]-2,5-di-O-triethylsilyl-β-D-glucofuranurono-γ-lactone revealed a ¹T₂-like conformation is preferred for the furanoid ring, while the γ-lactone system adopts an E₄ conformation. This structure supports the properties associated with the anomeric effect for furanosides.

N-(L-2-Amino­penta­noyl)-L-phenyl­alanine dihydrate, a hydro­phobic dipeptide with a nonproteinogenic residue

The title dipeptide has a nonproteinogenic N-terminal residue. The crystal structure is divided into distinct hydro­phobic and hydro­philic layers, the latter encompassing cocrystallized water mol­ecules connecting the charged N- and C-terminal groups.

2-[Anilino(di­phenyl­phosphoryl)methyl]phenol from a three-component Kabachnik–Fields reaction

The title compound was synthesized in high yield by a three-component Kabachnik–Fields reaction. It precipitates as racemic crystals in which strong hydrogen bonds between the hy­droxy group and the P=O group of a neighbouring mol­ecule form one-dimensional heterochiral chains.

3,4-Di­methyl-N-[1-(1H-pyrrol-2-yl)ethyl­idene]aniline and the 1-(1-thio­phen-2-yl) analogue

Two basic heterocyclic imino structures display a planar backbone with similar features, but differ in the heterocyclic atoms located in the five-membered rings, i.e. N and S. In the pyrrole, centrosymmetric imino­pyrrole dimers are assembled by means of two inverted N—H⋯N hydrogen bonds and two inverted C—H⋯π inter­actions. In the thio­phene, however, mol­ecules are linked by nonclassical C—H⋯N hydrogen bonds in which the mol­ecules play the roles of both hydrogen-bond donors and acceptors, resulting in one-dimensional supra­molecular chains.

Reinvestigation of tricyclic a­cyclo­vir: characterization of a `proton-wire' model

While the crystal structure of tricyclic acyclovir dihydrate containing an (H₂O)₈ solvent water molecule cluster has been described previously, the disorder was incompletely modeled. In this work, the disorder model is extended and includes disorder of one tricyclic acyclovir hydroxy group across an inversion centre, leading to characterization of a concerted chain of O—H⋯O hydrogen bonds constituting a `proton-wire' structure.

3,3′-[(1RS,3SR)-2-Oxo­cyclo­hexane-1,3-di­yl]bis­[(3RS,3′SR)-3-hy­droxy­indolin-2-one] dihydrate: organic layers of R₂²(8), R₂²(16) and R₆⁶(40) rings linked by tetra­meric water aggregates

Hydrogen-bonded sheets of organic mol­ecules are linked into a three-dimensional layer structure by cyclic centrosymmetric water tetra­mers.