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Naphthalene derived dications bearing different N-heterocyclic substituents appended at different positions demonstrated conformational flexibility and interesting self-assembled packing motifs when crystallised in the solid state as bromide salts.

p-Sulfonatocalix[4]arene dimers encapsulate mono- and multicharged imidazolium guests within antiparallel bilayer arrays, in one case forming unusual hydrated nanoscale channels that span this common arrangement.

The novel 2,7-bis((TIPS)ethynyl)-10b,10c-diethyldihydropyrene photochrome (TIPS = triisopropylsilyl) was observed to undergo thermal rearrangement to 2,7-bis(TIPS-ethynyl)-pyrene in the solid state...

The title compound, [Fe(C3H7NO)6][Cd2Cl7], crystallizes in the trigonal space group R\overline{3} and is assembled from discrete [Fe(DMF)6]3+ cations (DMF = N,N-dimethylformamide) and [Cd2Cl7]3− anions. In the cation, the iron(III) atom, located on a special position of \overline{3} site symmetry, is coordinated by six oxygen atoms from DMF ligands with all Fe—O distances being equal [2.0072 (16) Å]. A slight distortion of the octahedral environment of the metal comes from the cis O—Fe—O angles deviating from the ideal value of 90° [86.85 (7) and 93.16 (7)°] whilst all the trans angles are strictly 180°. The central Cl atom of the [Cd2Cl7]3− anion is also located on a special position of \overline{3} site symmetry and bridges two corner sharing, tetrahedrally coordinated CdII atoms. The two Cd atoms and the central Cl atom are colinear. The two sets of terminal chloride ligands on either side of the dumbbell-like anion are rotated relative to each other by 30°. In the crystal, the cations and anions, stacked one above the other along the c-axis direction, are held in place principally by electrostatic interactions. There are also C—H...Cl and C—H...O interactions, but these are rather weak. Of the six crystal structures reported to date for ionic salts of [Fe(DMF)6] n+ cations (n = 2, 3), five contain FeII ions. The title compound is the second example of a stable compound containing the [Fe(DMF)6]3+ cation. The existence of both [Fe(DMF)6]2+ and [Fe(DMF)6]3+ cations shows that the DMF ligand coordination sphere can accommodate changes in the charge and spin states of the metal centre.

The present paper reports on the synthesis and structure of bis(2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide) or bis(lidocaine) tetrachloridocuprate(II). The complex with the formula (C14H23ON2)2CuCl4 (or (LidH)2[CuCl4]), crystallizes in the monoclinic space group P21/c with a = 15.7831(2), b = 24.2992(2), c = 17.8748(2) Å, β = 104.874(1)°,V = 6625.58(13) Å3, Z = 8, and Dc = 1.355 Mg/m3. The coordination of the Cu2+ ions with chlorine atoms generates two differently distorted tetrahedral anions [CuCl4]2–, while four protonated cations LidH+ remain in an outer coordination sphere. Anions and cations are associated by hydrogen bonds of the N–H···Cl type to form the 2((LidH)2[CuCl4]) dimer, in which the distance between two copper atoms is 8.95 Å. With the help of hydrogen bonds of the type N–H···O and N–H···Cl, each dimer is connected with four neighboring dimers, resulting in a three-dimensional structure in which dimers lie at an angle of 28.39° to the a crystallographic axis in the ab planes located at a distance of 10.67 Å from each other.

The synthesis and spectroscopic and structural characterisation of new 3,5-dibromophenyl-functionalised imidazolium salts and their corresponding [Au(NHC)2]+ complexes is reported. X-ray diffraction studies revealed intra- and intermolecular interactions involving the 3,5-dibromophenyl group, including Br…π interactions with imidazolyl and C6 arene rings. Au-NHC complexes functionalised with 3,5-dibromophenyl substituents showed potent activity against OVCAR-8 (ovarian cancer) cells at low micromolar concentrations.

Driven by an interest in the impact of the para-substituent of calix[4]arenes on metal complexation and structural chemistry, studies of p-cyclohexylcalix[4]arene (L) have been carried out. The 1:1 dichloromethane and dimethylformamide solvates were found to be isostructural, and different to the typical bilayer structure often observed for p-t-butylcalix[4]arene solvates. The methanol solvate, in contrast, does form a bilayered structure but is also a 1:1 solvate, unlike the p-t-butylcalix[4]arene·2MeOH system. Lanthanoid complexation was investigated, resulting in the structural characterisation of two different DMF solvates of a 2:2 dimeric europium complex, Eu2(L–3H)2(DMF)4. A tetrazole derivative, 5,11,17,23-tetracyclohexyl-25,27-dihydroxy-26,28-bis(tetrazole-5-ylmethoxy)calix[4]arene, has been synthesised via the intermediate 5,11,17,23-tetracyclohexyl-25,27-dihydroxy-26,28-dicyanomethoxycalix[4]arene, with the latter compound being structurally characterised. Attempts to isolate lanthanoid clusters supported by the tetrazole derivative under conditions known to form Ln19 clusters with the p-t-butyl analogue were unsuccessful, resulting only in isolation of the ligand from the reaction mixture.

Leaving a mixture of excess N,N,N′,N′-tetramethyl-1,4-butanediamine (Me4BDA) with p-t-butylcalix[8]arene (L) and [(UO2)(dmso)5](ClO4)2 in a 1:2 ratio in acetonitrile solution to stand for an extended period resulted in the deposition of a mixture of three different crystalline materials. Single crystal X-ray structural studies were carried out to determine that the three materials were the solvated uncomplexed macrocycle L.1.5MeCN, and two uranyl complexes. These were formulated as (Me4BDAH2)2+[(HO)(UO2)2(L-5H)]2–·9MeCN·H2O and (Me4BDAH2)2+[HO(UO2)2{L-5H)]2–·(Me3BDAH)+[H2O(UO2)2(L-5H)]−·Me4BDA·14MeCN·H2O·CH3OH respectively. In contrast to analogous systems based on 1,2-ethanediamine and 1,3-propanediamine derivatives, extension of the chain length separating the N-centres to (CH2)4 in the present systems has resulted in the formation of polymeric chains where the calixuranate anions are linked by H-bond acceptance from diammonium units. These links are still not completely direct and pass in part through solvent bridges. Direct double interactions do occur in the inverse situation where the calixarene acts as an H-bond donor to neutral 1,4-butanediamine species but lead only to dimerisation.

Three new NiII/ZnII heterometallics, [NiZnL′2(OMe)Cl]2 (1), [NiZnL′′(Dea)Cl]2·2DMF (2) and [Ni2(H3L′′′)2(o-Van)(MeOH)2]Cl·[ZnCl2(H4L′′′)(MeOH)]·2MeOH (3), containing three-dentate Schiff bases as well as methanol or diethanolamine (H2Dea) or o-vanillin (o-VanH), all deprotonated, as bridging ligands were synthesized and structurally characterized. The Schiff base ligands were produced in situ from o-VanH and CH3NH2 (HL′), or NH2OH (HL”), or 2-amino-2-hydroxymethyl-propane-1,3-diol (H4L′′′); a zerovalent metal (Ni and Zn in 1, Zn only in 2 and 3) was employed as a source of metal ions. The first two complexes are dimers with a Ni2Zn2O6 central core, while the third compound is a novel heterometallic cocrystal salt solvate built of a neutral zwitterionic ZnII Schiff base complex and of ionic salt containing dinuclear NiII complex cations. The crystal structures contain either centrosymmetric (1 and 2) or non-symmetric di-nickel fragment (3) with Ni⋯Ni distances in the range 3.146–3.33 A. The exchange coupling is antiferromagnetic for 1, J = 7.7 cm−1, and ferromagnetic for 2, J = −6.5 cm−1 (using the exchange Hamiltonian in a form Ĥ = JŜ1Ŝ2). The exchange interactions in 1 and 2 are comparable to the zero-field splitting (ZFS). High-field EPR revealed moderate magnetic anisotropy of opposite signs: D = 2.27 cm−1, E = 0.243 cm−1 (1) and D = −4.491 cm−1, E = −0.684 cm−1 (2). Compound 3 stands alone with very weak ferromagnetism (J = −0.6 cm−1) and much stronger magnetic anisotropy with D = −11.398 cm−1 and E = −1.151 cm−1. Attempts to calculate theoretically the exchange coupling (using the DFT “broken symmetry” method) and ZFS parameters (with the ab initio CASSCF method) were successful in predicting the trends of J and D among the three complexes, while the quantitative results were less good for 1 and 3.

A convenient modification to the established synthetic routes for the preparation of complexes [M(CCR)(dppe)Cp′] (M = Fe, Ru; Cp′ = η5-C5H5 (Cp), η5-C5Me5 (Cp*); R = C6H5, C6H4-p-OMe, C6H4-p-NO2, tBu) and [Ru(CCR)(PPh3)2Cp] from the corresponding [MCl(PP)Cp′] complex and the alkyne HCCR via an intermediate vinylidene is described. The complexes are generally obtained as high quality crystalline samples directly from the reaction mixture. In agreement with previous studies, the iron complexes undergo a predominantly metal-centred oxidation, whilst there is greater involvement of the acetylide ligand in the oxidation processes associated with the ruthenium analogues. Analysis of the redox properties and spectroelectrochemical investigations reveal limited differences in the gross electronic structures of the Cp vs. Cp* derivatives in each of the Fe and Ru series.

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 aux...

The syntheses and crystallographically determined structures of metal complexes trans-[M(C≡CR)2Ln] (MLn = Ru(dppe)2, Ru{P(OEt)3}4, Pt(PEt3)2) featuring acetylide ligands further functionalized by a...

Structural studies on p-sulfonatocalix[4]arene coordination compounds involving diverse metal ions with respect to their size and charge, caesium(I), copper(II) and neodymium(III) are reported. The...

Four multi-component complexes based on p-sulfonatocalix[4]arene anion, the methyltriphenylphosphonium cation, lanthanide ions (Gd(III)) and different ionic liquid-based cations (1-methyl-3-butylim...

Three Re(I) tricarbonyl complexes, with the general formulation Re(N^L)(CO)3X (where N^L is a bidentate ligand containing a pyridine functionalized at position 2 with a thione or a thiazol-2-yliden...

This paper reports on the synthesis and structure re-refinement of bis(lidocaine) diaquatetrathiocyanatonickelate(II). The compound with the formula (LidH)2[Ni(NCS)4(H2O)2], where Lid is (2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide, crystallizes in the monoclinic space group P21/c with a= 18.3509(5), b= 7.6532(2), c= 14.9585(4) Å, β= 109.964 (2)°, V= 1974.57 (9) Å3, and Z= 2. Coordination of the Ni2+ ion with thiocyanate ions and water molecules generates slightly distorted octahedral anion [Ni(NCS)4(H2O)2]2– with N-bonded thiocyanate groups, while two protonated cations LidH+ remain in an outer coordination field.

Reactions of [Ru{C=C(H)-1,4-C6 H4 C≡CH}(PPh3 )2 Cp]BF4 ([1 a]BF4 ) with hydrohalic acids, HX, results in the formation of [Ru{C≡C-1,4-C6 H4 -C(X)=CH2 }(PPh3 )2 Cp] [X=Cl (2 a-Cl), Br (2 a-Br)], arising from facile Markovnikov addition of halide anions to the putative quinoidal cumulene cation [Ru(=C=C=C6 H4 =C=CH2 )(PPh3 )2 Cp]+ . Similarly, [M{C=C(H)-1,4-C6 H4 -C≡CH}(LL)Cp ]BF4 [M(LL)Cp'=Ru(PPh3 )2 Cp ([1 a]BF4 ); Ru(dppe)Cp* ([1 b]BF4 ); Fe(dppe)Cp ([1 c]BF4 ); Fe(dppe)Cp* ([1 d]BF4 )] react with H+ /H2 O to give the acyl-functionalised phenylacetylide complexes [M{C≡C-1,4-C6 H4 -C(=O)CH3 }(LL)Cp'] (3 a-d) after workup. The Markovnikov addition of the nucleophile to the remote alkyne in the cations [1 a-d]+ is difficult to rationalise from the vinylidene form of the precursor and is much more satisfactorily explained from initial isomerisation to the quinoidal cumulene complexes [M(=C=C=C6 H4 =C=CH2 )(LL)Cp']+ prior to attack at the more exposed, remote quaternary carbon. Thus, whilst representative acetylide complexes [Ru(C≡C-1,4-C6 H4 -C≡CH)(PPh3 )2 Cp] (4 a) and [Ru(C≡C-1,4-C6 H4 -C≡CH)(dppe)Cp*] (4 b) reacted with the relatively small electrophiles [CN]+ and [C7 H7 ]+ at the β-carbon to give the expected vinylidene complexes, the bulky trityl ([CPh3 ]+ ) electrophile reacted with [M(C≡C-1,4-C6 H4 -C≡CH)(LL)Cp'] [M(LL)Cp'=Ru(PPh3 )2 Cp (4 a); Ru(dppe)Cp* (4 b); Fe(dppe)Cp (4 c); Fe(dppe)Cp* (4 d)] at the more exposed remote end of the carbon-rich ligand to give the putative quinoidal cumulene complexes [M{C=C=C6 H4 =C=C(H)CPh3 }(LL)Cp']+ , which were isolated as the water adducts [M{C≡C-1,4-C6 H4 -C(=O)CH2 CPh3 }(LL)Cp'] (6 a-d). Evincing the scope of the formation of such extended cumulenes from ethynyl-substituted arylvinylene precursors, the rather reactive half-sandwich (5-ethynyl-2-thienyl)vinylidene complexes [M{C=C(H)-2,5-c C4 H2 S-C≡CH}(LL)Cp']BF4 ([7 a-d]BF4 add water readily to give [M{C≡C-2,5-c C4 H2 S-C(=O)CH3 }(LL)Cp'] (8 a-d)].

Herein, we report a Rh(II)-catalyzed reaction between 1-tosyl-1,2,3-triazoles and halohydrins to provide 2,6-substituted 3,4-dihydro-2H-1,4-oxazines under basic conditions. The reaction is proposed...

A series of chiral N-heterocyclic carbene (NHC)-iridium complexes of general formula [(NHC*)Ir(diene)Cl] bearing TFB (tetrafluorobenzobarrelene), TCB (tetrachlorobenzobarrelene), BB (benzobarrelene), and COD (cyclooctadiene) as diene ligands were synthesized and fully characterized. Chiral NHC ligands used were of the type previously reported from our group, with backbone stereocenters as well as axial chirality present. The cationic NHC-iridium complexes [(NHC*)Ir(diene)][PF6] were obtained via chloride abstraction from [(NHC*)Ir(diene)Cl] with AgPF6. X-ray crystallographic data for some of the neutral and cationic complexes were obtained and analyzed. The topographic steric bulk of the chiral NHC ligands was calculated using the SambVca 2.0 program. While attempting to get a single crystal of the unstable (Ra,Ra,S,S)-[(DiPh-2-SICyoctNap)Ir(BB)][PF6] complex, a decomposition product with an unexpected pincer-type NHC*-diene ligand was obtained. The series of chiral cationic NHC-iridium complexes were eit...

Eight organic salts made up of two different organic phosphonium monocations, tetraphenylphosphonium or benzyltriphenylphosphonium, and common anions of different shape, size and charge distribution have been structurally authenticated. The crystal packing for the tetraphenylphosphonium cations involves one-dimensional infinite stacked columns incorporating translational quadruple embraces (TQPE) regardless of the type of counter ion. As for benzyltriphenylphosphonium salts, different packing arrays were obtained with different anions. Interestingly, the anions control the intermolecular packing of the same phosphonium cation, while hydrogen bonding is found to be the dominant contributor in the overall self-assembly. Hydrophobic interactions between the phosphonium cations driven by the phenyl–phenyl embrace involving π⋯π and/or C–H⋯π interactions also contribute to the cohesion of the structures. Charge-assisted hydrogen bonding and halogen bonding were also evident, which are relatively strong compared to classical hydrogen bonds, as judged from the short intermolecular distances. The interactions have also been quantified using Hirshfeld surfaces analyses.

Trinuclear lanthanoid clusters have been synthesised and investigated as toroidal spin systems. A pyridyl functionalised β-diketonate, 1,3-bis(pyridin-2-yl)propane-1,3-dione (o-dppdH) has been used to synthesise a family of clusters of the form [Dy3(OH)2(o-dppd)3Cl2(H2O)4]Cl2·7H2O (1), [Tb3(o-dppd)3(μ3-OH)2(CH3CH2OH)3Cl3][Tb3(o-dppd)3(μ3-OH)2(H2O)(CH3CH2OH)2Cl3]Cl2·H2O (2), [Ho3(OH)2(o-dppd)3Cl(H2O)5]Cl3·3H2O (3) and [Er3(OH)2(o-dppd)3Cl2(H2O)3(CH3OH)]Cl2·3H2O·CH3OH (4). Despite the previous occurrence of this structural motif in the literature, these systems have not been widely investigated in terms of torodic behaviour. Magnetic studies were used to further characterise the complexes. DC susceptibility studies support weak antiferromagnetic exchange in the complexes. Slow magnetic relaxation behaviour is observed in the dynamic AC magnetic studies for complex 1. Theoretical studies predict that complex 1 and 3 have a non-magnetic ground state based on a toroidal arrangement of spins. Changes to the coordination environment in 2 do not support a toroic spin state. The prolate nature of the ErIII centres in complex 4 and large transverse anisotropy do not support the toroidal arrangement of lanthanoid spins in the complex.

The organisation of the p-xylylenebis(triphenylphosphonium) dication in the solid state, in crystals formed under a variety of conditions, at different pH values and in the presence of THF and other potential building moieties including p-sulfonatocalix[4]arene, 1-methyl-3-butylimidazolium and aquated gadolinium(III) has been investigated using single crystal X-ray diffraction studies. Striking changes in the dication conformations (cis- and trans-) that contribute to the different crystal packings of the dication (two-dimensional layerings and three-dimensional scaffoldings) have been established for five different compounds. The interplay and the self-assembled arrays of the dication with other incorporated components and the overall non-covalent interactions have been quantified using Hirshfeld surface analyses.

The interplay of organic dications bearing various n-alkylimidazolium termini substituted at different positions on a bis(methylene)phenyl ring and p-sulfonatocalix[4]arene, along with tetraphenylphosphonium cations and hydrated lanthanides (Ce3+, Er3+ and Gd3+), afforded various self-assembled solid-state structures. The host–guest binding behaviour of the dications and p-sulfonatocalix[4]arene was carefully investigated by crystallographic studies including their interactions in the solution state, but in the absence of phosphonium and lanthanide cations via1H NMR experiments.

This paper describes the syntheses of several functionalized dihydropyrene (DHP) molecular switches with different substitution patterns. Regioselective nucleophilic alkylation of a 5-substituted dimethyl isophthalate allowed the development of a workable synthetic protocol for the preparation of 2,7-alkyne-functionalized DHPs. Synthesis of DHPs with surface-anchoring groups in the 2,7- and 4,9-positions is described. The molecular structures of several intermediates and DHPs were elucidated by X-ray single-crystal diffraction. Molecular properties and switching capabilities of both types of DHPs were assessed by light irradiation experiments, spectroelectrochemistry, and cyclic voltammetry. Spectroelectrochemistry, in combination with density functional theory (DFT) calculations, shows reversible electrochemical switching from the DHP forms to the cyclophanediene (CPD) forms. Charge-transport behavior was assessed in single-molecule scanning tunneling microscope (STM) break junctions, combined with density functional theory-based quantum transport calculations. All DHPs with surface-contacting groups form stable molecular junctions. Experiments show that the molecular conductance depends on the substitution pattern of the DHP motif. The conductance was found to decrease with increasing applied bias.

Herein we describe the synthesis and isolation of the first low-valent NHC-phosphite nickel complexes of general formula Ni(NHC)[P(OAr)3]2. These three-coordinate Ni(0) compounds were fully charact...

Bioactive natural products underpin the intriguing pollination strategy used by sexually deceptive orchids. These compounds, which mimic the sex pheromones of the female insect, are emitted in particular blends to lure male insect pollinators of specific species. By combining methods from field biology, analytical chemistry, electrophysiology, crystallography, and organic synthesis, we report that an undescribed β-hydroxylactone, in combination with two specific hydroxymethylpyrazines, act as pollinator attractants in the rare hammer orchid Drakaea micrantha. This discovery represents an unusual case of chemically unrelated compounds being used together as a sexual attractant. Furthermore, this is the first example of the identification of pollinator attractants in an endangered orchid, enabling the use of chemistry in orchid conservation. Our synthetic blend is now available to be used in pollinator surveys to locate suitable sites for plant conservation translocations.

The etiology of fungal pathogenesis of grains is critical to global food security. The large number of orphan biosynthetic gene clusters uncovered in fungal plant pathogen genome sequencing project...

Octa­hedral [Fe(DMF)6]3+ and tetra­hedral-based [Cd2Cl7]3− ions stack alternately along the c-axis direction in this rare example of a [Fe(DMF)6]3+-containing ionic salt., The title compound, [Fe(C3H7NO)6][Cd2Cl7], crystallizes in the trigonal space group R and is assembled from discrete [Fe(DMF)6]3+ cations (DMF = N,N-di­methyl­formamide) and [Cd2Cl7]3− anions. In the cation, the iron(III) atom, located on a special position of site symmetry, is coordinated by six oxygen atoms from DMF ligands with all Fe—O distances being equal [2.0072 (16) Å]. A slight distortion of the octa­hedral environment of the metal comes from the cis O—Fe—O angles deviating from the ideal value of 90° [86.85 (7) and 93.16 (7)°] whilst all the trans angles are strictly 180°. The central Cl atom of the [Cd2Cl7]3− anion is also located on a special position of site symmetry and bridges two corner sharing, tetra­hedrally coordinated CdII atoms. The two Cd atoms and the central Cl atom are colinear. The two sets of terminal chloride ligands on either side of the dumbbell-like anion are rotated relative to each other by 30°. In the crystal, the cations and anions, stacked one above the other along the c-axis direction, are held in place principally by electrostatic inter­actions. There are also C—H⋯Cl and C—H⋯O inter­actions, but these are rather weak. Of the six crystal structures reported to date for ionic salts of [Fe(DMF)6]n+ cations (n = 2, 3), five contain FeII ions. The title compound is the second example of a stable compound containing the [Fe(DMF)6]3+ cation. The existence of both [Fe(DMF)6]2+ and [Fe(DMF)6]3+ cations shows that the DMF ligand coordination sphere can accommodate changes in the charge and spin states of the metal centre.

Developing molecular circuits that can function as the active components in electrical devices is an ongoing challenge in molecular electronics. It demands mechanical stability of the single-molecule circuit while simultaneously being responsive to external stimuli mimicking the operation of conventional electronic components. Here, we report single-molecule circuits based on spiropyran derivatives that respond electrically to chemical and mechanical stimuli. The merocyanine that results from the protonation/ring-opening of the spiropyran form showed single-molecule diode characteristics, with an average current rectification ratio of 5 at ±1 V, favoring the orientation where the positively charged end of the molecule is attached to the negative terminal of the circuit. Mechanical pulling of a single spiropyran molecule drives a switch to a more conducting merocyanine state. The mechanical switching is enabled by the strong Au-C covalent bonding between the molecule and the electrodes, which allows the tensile force delivered by the STM piezo to break the molecule at its spiropyran C-O bond.

TFB (tetrafluorobenzobarrelene), TCB (tetrachlorobenzobarrelene), and BB (benzobarrelene) are introduced as alternative diene ligands to COD (1,5-cyclooctadiene) for NHC–iridium complexes of the ge...

The monocation product of the oxidative condensation–cyclization between two molecules of pyridine-2-carbaldehyde and one molecule of CH3NH2·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridinium, was isolated in the presence of metal ions as bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] tetraiodocadmate, (C13H12N3)2[CdI4], (I), and the mixed chloride/nitrate salt, bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] 1.5-chloride 0.5-nitrate trihydrate, 2C13H12N3 +·1.5Cl−·0.5NO3 −·3H2O, (II). Hybrid salt (I) crystallizes in the space group P21/n with two [L]2[CdI4] molecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetrahalometallate anions are stacked parallel to the ab plane. Antiparallel L + cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetrahedral CdI4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis; the one-dimensional hydrogen-bonded polymer built of chloride ions and water molecules runs parallel to a column of stacked cations.

The first approaches to the 10′-anthronyl-2-anthraquinone skeleton have been devised, allowing two syntheses of the marine natural product albopunctatone. Both routes involve regioselective addition of a nucleophilic masked anthraquinone to a protected chrysazin derivative; the best affords albopunctatone in five steps and 35% overall yield. Albopunctatone exhibits potent inhibitory activity against Plasmodium falciparum and negligible toxicity to a range of other microbial pathogens and mammalian cells.

The observation of an unusual crystal habit in the common diuretic drug hydrochlorothiazide (HCT), and identification of its subtle conformational chirality, has stimulated a detailed investigation of its crystalline forms. Enantiomeric conformers of HCT resolve into an unusual structure of conjoined enantiomorphic twin crystals comprising enantiopure domains of opposite chirality. The purity of the domains and the chiral molecular conformation are confirmed by spatially revolved synchrotron micro-XRD experiments and neutron diffraction, respectively. Macroscopic inversion twin symmetry observed between the crystal wings suggests a pseudoracemic structure that is not a solid solution or a layered crystal structure, but an unusual structural variant of conglomerates and racemic twins. Computed interaction energies for molecular pairs in the racemic and enantiopure polymorphs of HCT, and the observation of large opposing unit-cell dipole moments for the enantiopure domains in these twin crystals, suggest a plausible crystal nucleation mechanism for this unusual crystal habit.

Several trinuclear ferrocenes are obtained by Friedel-Crafts reaction of octamethylferrocene with ferrocenoyl chloride and subsequent modifications. 1,1'-Diferrocenoyloctamethylferrocene (3) is transformed to the divinyl derivative (4a) by reaction with MeLi and AlCl

The synthesis, structural and photophysical characterisation of four tricarbonyl rhenium(i) complexes bound to 1,10-phenanthroline and a tetrazolato ancillary ligand are reported. The complexes are differentiated by the nature (hydroxy or methoxy) and position (meta or para) of the substituent attached to the phenyl ring in conjugation to the tetrazole ring. The complexes exhibit phosphorescence emission from triplet charge transfer excited states, with the maxima around 600 nm, excited state lifetime decays in the 200-300 ns range, and quantum yield values of 4-6% in degassed acetonitrile solutions. The nature and position of the substituent does not significantly affect the photophysical properties, which remain unchanged even after deprotonation of the hydroxide group on the phenol ring. The interpretation of the photophysical data was further validated by resonance Raman spectroscopy and time-dependent density functional theory calculations. All the complexes are internalised within cells, albeit to variable degrees. As highlighted by a combination of flow cytometry and confocal microscopy, the species display diffuse cytoplasmic localisation except for the complex with the hydroxy functional group at the para position, which reveals lower accumulation in cells and more pronounced punctate staining. Overall, the complexes displayed low levels of cytotoxicity.

Three new NiII/ZnII heterometallics, [NiZnL'2(OMe)Cl]2 (1), [NiZnL''(Dea)Cl]2·2DMF (2) and [Ni2(H3L''')2(o-Van)(MeOH)2]Cl·[ZnCl2(H4L''')(MeOH)]·2MeOH (3), containing three-dentate Schiff bases as well as methanol or diethanolamine (H2Dea) or o-vanillin (o-VanH), all deprotonated, as bridging ligands were synthesized and structurally characterized. The Schiff base ligands were produced in situ from o-VanH and CH3NH2 (HL'), or NH2OH (HL"), or 2-amino-2-hydroxymethyl-propane-1,3-diol (H4L'''); a zerovalent metal (Ni and Zn in 1, Zn only in 2 and 3) was employed as a source of metal ions. The first two complexes are dimers with a Ni2Zn2O6 central core, while the third compound is a novel heterometallic cocrystal salt solvate built of a neutral zwitterionic ZnII Schiff base complex and of ionic salt containing dinuclear NiII complex cations. The crystal structures contain either centrosymmetric (1 and 2) or non-symmetric di-nickel fragment (3) with NiNi distances in the range 3.146-3.33 Å. The exchange coupling is antiferromagnetic for 1, J = 7.7 cm-1, and ferromagnetic for 2, J = -6.5 cm-1 (using the exchange Hamiltonian in a form Ĥ = Jŝ1ŝ2). The exchange interactions in 1 and 2 are comparable to the zero-field splitting (ZFS). High-field EPR revealed moderate magnetic anisotropy of opposite signs: D = 2.27 cm-1, E = 0.243 cm-1 (1) and D = -4.491 cm-1, E = -0.684 cm-1 (2). Compound 3 stands alone with very weak ferromagnetism (J = -0.6 cm-1) and much stronger magnetic anisotropy with D = -11.398 cm-1 and E = -1.151 cm-1. Attempts to calculate theoretically the exchange coupling (using the DFT "broken symmetry" method) and ZFS parameters (with the ab initio CASSCF method) were successful in predicting the trends of J and D among the three complexes, while the quantitative results were less good for 1 and 3.

Chiral, cationic NHC–iridium complexes are introduced as catalysts for the intramolecular hydroamination reaction of unactivated aminoalkenes. The catalysts show high activity in the construction of a range of 5- and 6-membered N-heterocycles, which are accessed in excellent optical purity, with various functional groups being tolerated with this system. A major deactivation pathway is presented and eliminated by using alternative reaction conditions. A detailed experimental and computational study on the reaction mechanism is performed providing valuable insights into the mode of action of the catalytic system and pointing to future modifications to be made for this catalytic platform., Chiral, cationic NHC–iridium complexes are introduced as catalysts for the intramolecular hydroamination reaction of unactivated aminoalkenes.

Three Re(I) tricarbonyl complexes, with general formulation Re(N^L)(CO)3X (where N^L is a bidentate ligand containing a pyridine functionalized in the position 2 with a thione or a thiazol-2-ylidene group and X is either chloro or bromo) were synthesized and their reactivity explored in terms of solvent-dependent ligand substitution, both in the ground and excited states. When dissolved in acetonitrile, the complexes bound to the thione ligand underwent ligand exchange with the solvent resulting in the formation of Re(NCMe)2(CO)3X. The exchange was found to be reversible, and the starting complex was reformed upon removal of the solvent. On the other hand, the complexes appeared inert in dichloromethane or acetone. Conversely, the complex bound to the thiazole-2-ylidene ligand did not display any ligand exchange reaction in the dark, but underwent photoactivated ligand substitution when excited to its lowest metal-to-ligand charge transfer manifold. Photolysis of this complex in acetonitrile generated multiple products, including Re(I) tricarbonyl and dicarbonyl solvato-complexes as well as free thiazole-2-ylidene ligand.

Herein, we report a Rh(II)-catalyzed reaction between 1-tosyl-1,2,3-triazoles and halohydrins to provide 2,6-substituted 3,4-dihydro-2

Two previously reported bis-indole alkaloids, echinosulfone A and echinosulfonic acid B, have been isolated for the first time from a Western Australian marine sponge, Crella sp. (order: Poecilosclerida, family: Crellidae). Single-crystal X-ray diffraction of a decomposition product of echinosulfone A prompted our investigation and subsequent structure reassignment of the echinosulfonic acid natural product family, which we report here. The reassignments are supported by analysis of 1D and 2D NMR data, MS fragmentation, and DFT calculations of 13C NMR shifts.

Ten manganese(I) tricarbonyl diimine complexes bound to variably functionalised 5-aryl-tetrazolato ligands were prepared, and their photochemical properties were investigated. Upon exposure to light at 365 nm, each complex decomposed to its free diimine and tetrazolato ligands, simultaneously dissociating three CO ligands, as evidenced by changes in the IR spectra of the irradiated complexes over time. The anti-bacterial properties of one of these complexes were tested against Escherichia coli. While the complex displayed no effect on the bacterial growth in the dark, pre-irradiated solutions inhibited bacterial growth. Comparative studies revealed that the antibacterial properties originate from the presence of free 1,10-phenanthroline.