Crystal structures of four gold(I) complexes [AuL 2]+[AuX 2]- and a by-product (L·LH+)[AuBr2]- (L = substituted pyridine, X = Cl or Br).

Bis(2-methyl-pyridine)-gold(I) di-bromido-aurate(I), [Au(C6H7N)2][AuBr2], (1), crystallizes in space group C2/c with Z = 4. Both gold atoms lie on twofold axes and are connected by an aurophilic contact. A second aurophilic contact leads to infinite chains of alternating cations and anions parallel to the b axis, and the residues are further connected by a short H⋯Au contact and a borderline Br⋯Br contact. Bis(3-methyl-pyridine)-gold(I) di-bromido-aurate(I), [Au(C6H7N)2][AuBr2], (2), crystallizes in space group C2/m with Z = 2. Both gold atoms lie on special positions with symmetry 2/m and are connected by an aurophilic contact; all other atoms except for one methyl hydrogen lie in mirror planes. The extended structure is closely analogous to that of 1, although the structures are formally not isotypic. Bis(3,5-di-methyl-pyridine)-gold(I) di-chlor-ido-aurate(I), [Au(C7H9N)2][AuCl2], (3) crystallizes in space group P with Z = 2. The cation lies on a general position, and there are two independent anions in which the gold atoms lie on inversion centres. The cation and one anion associate via three short H⋯Cl contacts to form a ribbon structure parallel to the b axis; aurophilic contacts link adjacent ribbons. Bis(3,5-di-methyl-pyridine)-gold(I) di-bromido-aurate(I), [Au(C7H9N)2][AuBr2], (4) is isotypic to 3. Attempts to make similar compounds involving 2-bromo-pyridine led instead to 2-bromopyridinium di-bromido-aurate(I)-2-bromo-pyridine (1/1), (C5H5BrN)[AuBr2]·C5H4BrN, (5), which crystallizes in space group P with Z = 2; all atoms lie on general positions. The 2-bromo-pyridinium cation is linked to the 2-bromo-pyridine mol-ecule by an N-H⋯N hydrogen bond. Two formula units aggregate to form inversion-symmetric dimers involving Br⋯Br, Au⋯Br and H⋯Br contacts.

Crystal structures of fourteen halochalcogenylphos-pho-nium tetra-halogenidoaurates(III).

The structures of fourteen halochalcogenyl-phospho-nium tetra-halogen-ido-aurates(III), phosphane chalcogenide derivatives with general formula [R 1 3- nR 2 nPEX][AuX 4] (R 1 = t-butyl; R 2 = isopropyl; n = 0 to 3; E = S or Se; X = Cl or Br) are presented. The eight possible chlorido derivatives are: 17 a, n = 3, E = S; 18 a, n = 2, E = S; 19 a, n = 1, E = S; 20 a, n = 0, E = S; 21 a, n = 3, E = Se; 22 a, n = 2, E = Se; 23 a, n = 1, E = Se; and 24 a, n = 0, E = Se, and the corresponding bromido derivatives are 17 b-24 b in the same order. Structures were obtained for all compounds except for the tri-t-butyl derivatives 24 a and 24 b. Isotypy is observed for 18 a/18 b/22 a/22 b, 19 a/23 a, 17 b/21 b and 19 b/23 b. In eleven of the compounds, X⋯X contacts (mostly very short) are observed between the cation and anion, whereby the E-X⋯X groups are approximately linear and the X⋯X-Au angles approximately 90°. The exceptions are 17 a, 19 a and 23 a, which instead display short E⋯X contacts. Bond lengths in the cations correspond to single bonds P-E and E-X. For each group with constant E and X, the P-E-X bond-angle values increase monotonically with the steric bulk of the alkyl groups. The packing is analysed in terms of E⋯X, X⋯X (some between anions alone), H⋯X and H⋯Au contacts. Even for isotypic compounds, some significant differences can be discerned.

Crystal structure of (E)-N-(4-bromo-phen-yl)-2-cyano-3-[3-(2-methyl-prop-yl)-1-phenyl-1H-pyrazol-4-yl]prop-2-enamide.

The structure of the title compound, C23H21BrN4O, contains two independent mol-ecules connected by hydrogen bonds of the type Namide-H⋯N≡C to form a dimer. The configuration at the exocyclic C=C double bond is E. The mol-ecules are roughly planar except for the isopropyl groups. There are minor differences in the orientations of these groups and the phenyl rings at N1. The dimers are further linked by 'weak' hydrogen bonds, two each of the types Hphen-yl⋯O=C (H⋯O = 2.50, 2.51 Å) and Hphen-yl⋯Br (H⋯Br = 2.89, 2.91 Å), to form ribbons parallel to the b and c axes, respectively. The studied crystal was a non-merohedral twin.

Crystal structures of tri-chlorido-(4-methyl-piperidine)gold(III) and two polymorphs of tri-bromido(4-methyl-piperidine)-gold(III).

Tri-chlorido-(4-methyl-piperidine)-gold(III), [AuCl3(C6H13N)], 1, crystallizes in Pbca with Z = 8. Tri-bromido-(4-methyl-piperidine)-gold(III), [AuBr3(C6H13N)], 2, crystallizes as two polymorphs, 2a in Pnma with Z = 4 (imposed mirror symmetry) and 2b, which is isotypic to 1. The Au-N bonds trans to Cl are somewhat shorter than those trans to Br, and the Au-Cl bonds trans to N are longer than those cis to N, whereas the Au-Br bonds trans to N are slightly shorter than the cis bonds. The methyl and AuX 3 groups (X = halogen) occupy equatorial positions at the six-membered ring. The packing of all three structures involves chains of mol-ecules with offset stacking of the AuX 3 moieties associated with short Au⋯X contacts; for 1 and 2b these are reinforced by N-H⋯X hydrogen bonds, whereas for 2a there are no classical hydrogen bonds and the chains are inter-connected by Br⋯Br contacts.

Silver Organometallics that are Highly Potent Thioredoxin and Glutathione Reductase Inhibitors: Exploring the Correlations of Solution Chemistry with the Strong Antibacterial Effects.

The antibacterial activity of silver species is well-established; however, their mechanism of action has not been adequately explored. Furthermore, issues of low-molecular silver compounds with cytotoxicity, stability, and solubility hamper their progress to drug leads. We have investigated silver N-heterocyclic carbene (NHC) halido complexes [(NHC)AgX, X = Cl, Br, and I] as a promising new type of antibacterial silver organometallics. Spectroscopic studies and conductometry established a higher stability for the complexes with iodide ligands, and nephelometry indicated that the complexes could be administered in solutions with physiological chloride levels. The complexes showed a broad spectrum of strong activity against pathogenic Gram-negative bacteria. However, there was no significant activity against Gram-positive strains. Further studies clarified that tryptone and yeast extract, as components of the culture media, were responsible for this lack of activity. The reduction of biofilm formation and a strong inhibition of both glutathione and thioredoxin reductases with IC50 values in the nanomolar range were confirmed for selected compounds. In addition to their improved physicochemical properties, the compounds with iodide ligands did not display cytotoxic effects, unlike the other silver complexes. In summary, silver NHC complexes with iodide secondary ligands represent a useful scaffold for nontoxic silver organometallics with improved physicochemical properties and a distinct mechanism of action that is based on inhibition of thioredoxin and glutathione reductases.

Linear Amine-Linked Oligo-BODIPYs: Convergent Access via Buchwald-Hartwig Coupling.

A convergent route toward nitrogen-bridged BODIPY oligomers has been developed. The synthetic key step is a Buchwald-Hartwig cross-coupling reaction of an α-amino-BODIPY and the respective halide. Not only does the selective synthesis provide control of the oligomer size, but the facile preparative procedure also enables easy access to these types of dyes. Furthermore, functionalized examples were accessible via brominated derivatives.

Crystal structure of 2,4-di-amino-5-(4-hy-droxy-3-meth-oxy-phen-yl)-8,8-dimethyl-6-oxo-6,7,8,9-tetra-hydro-5H-chromeno[2,3-b]pyridine-3-carbo-nitrile-di-methyl-formamide-water (1/1/1).

In the structure of the title compound, C22H22N4O4·C3H7NO·H2O, the entire tricyclic system is approximately planar except for the carbon atom bearing the two methyl groups; the meth-oxy-phenyl ring is approximately perpendicular to the tricycle. All seven potential hydrogen-bond donors take part in classical hydrogen bonds. The main mol-ecule and the DMF combine to form broad ribbons parallel to the a axis and roughly parallel to the ab plane; the water mol-ecules connect the residues in the third dimension.

Crystal structures of ten phosphane chalcogenide complexes of gold(III) chloride and bromide.

The structures of ten phosphane chalcogenide complexes of gold(III) halides, with general formula R 1 3-n R 2 nPEAuX 3 (R 1 = t-butyl; R 2 = i-propyl; n = 0 to 3; E = S or Se; X = Cl or Br) are presented. The eight possible chlorido derivatives are: 9a, n = 3, E = S; 10a, n = 2, E = S; 11a, n = 1, E = S; 12a, n = 0, E = S; 13a, n = 3, E = Se; 14a, n = 2, E = Se; 15a, n = 1, E = Se; and 16a, n = 0, E = Se, and the corresponding bromido derivatives are 9b-16b in the same order. Structures were obtained for 9a, 10a (and a second polymorph 10aa), 11a (and its deutero-chloro-form monosolvate 11aa), 12a (as its di-chloro-methane monosolvate), 14a, 15a (as its deutero-chloro-form monosolvate 15aa, in which the solvent mol-ecule is disordered over two positions), 9b, 11b, 13b and 15b. The structures of 11a, 15a, 11b and 15b form an isotypic set, and those of compounds 10aa and 14a form an isotypic pair. All structures have Z' = 1. The gold(III) centres show square-planar coordination geometry and the chalcogenide atoms show approximately tetra-hedral angles (except for the very wide angle in 12a, probably associated with the bulky t-butyl groups). The bond lengths at the gold atoms are lengthened with respect to the known gold(I) derivatives, and demonstrate a considerable trans influence of S and Se donor atoms on a trans Au-Cl bond. Each compound with an isopropyl group shows a short intra-molecular contact of the type C-Hmethine⋯Xcis; these may be regarded as intra-molecular 'weak' hydrogen bonds, and they determine the orientation of the AuX 3 groups. The mol-ecular packing is analysed in terms of various short contacts such as weak hydrogen bonds C-H⋯X and contacts between the heavier atoms, such as X⋯X (9a, 10aa, 11aa, 15aa and 9b), S⋯S (10aa, 11a and 12a) and S⋯Cl (10a). The packing of the polymorphs 10a and 10aa is thus quite different. The solvent mol-ecules take part in C-H⋯Cl hydrogen bonds; for 15aa, a disordered solvent region at z ≃ 0 is observed. Structure 13b involves unusual inversion-symmetric dimers with Se⋯Au and Se⋯Br contacts, further connected by Br⋯Br contacts.

Crystal structure of 4-(benzo[d]thia-zol-2-yl)-1,2-dimethyl-1H-pyrazol-3(2H)-one.

In the title compound, C12H11N3OS, the inter-planar angle between the pyrazole and benzo-thia-zole rings is 3.31 (7)°. In the three-dimensional mol-ecular packing, the carbonyl oxygen acts as acceptor to four C-H donors (with one H⋯O as short as 2.25 Å), while one methyl hydrogen is part of the three-centre system H⋯(S, O). A double layer structure parallel to (01) can be recognized as a subsection of the packing.

Crystal structure of 2-[(5-amino-1-tosyl-1H-pyrazol-3-yl)-oxy]-1-(4-meth-oxy-phen-yl)ethan-1-one 1,4-dioxane monosolvate.

In the structure of the title compound, C19H19N3O5S·C4H8O2, the two independent dioxane mol-ecules each display inversion symmetry. The pyrazole ring is approximately parallel to the aromatic ring of the oxy-ethanone group and approximately perpendicular to the tolyl ring of the sulfonyl substituent. An extensive system of classical and 'weak' hydrogen bonds connects the residues to form a layer structure parallel to (201), within which dimeric subunits are conspicuous; neighbouring layers are connected by classical hydrogen bonds to dioxanes and by 'weak' hydrogen bonds from Htol-yl donors.

Crystal structures of sixteen phosphane chalcogenide complexes of gold(I) chloride, bromide and iodide.

The structures of 16 phosphane chalcogenide complexes of gold(I) halides, with the general formula R 1 3- nR 2 nPEAuX (R 1 = t-butyl; R 2 = isopropyl; n = 0 to 3; E = S or Se; X = Cl, Br or I), are presented. The eight possible chlorido derivatives are: 1a, n = 3, E = S; 2a, n = 2, E = S; 3a, n = 1, E = S; 4a, n = 0, E = S; 5a, n = 3, E = Se; 6a, n = 2, E = Se; 7a, n = 1, E = Se; and 8a, n = 0, E = Se, and the corresponding bromido derivatives are 1b-8b in the same order. However, 2a and 2b were badly disordered and 8a was not obtained. The iodido derivatives are 2c, 6c and 7c (numbered as for the series a and b). All structures are solvent-free and all have Z' = 1 except for 6b and 6c (Z' = 2). All mol-ecules show the expected linear geometry at gold and approximately tetra-hedral angles P-E-Au. The presence of bulky ligands forces some short intra-molecular contacts, in particular H⋯Au and H⋯E. The Au-E bond lengths have a slight but consistent tendency to be longer when trans to a softer X ligand, and vice versa. The five compounds 1a, 5a, 6a, 1b and 5b form an isotypic set, despite the different alkyl groups in 6a. Compounds 3a/3b, 4b/8b and 6b/6c form isotypic pairs. The crystal packing can be analysed in terms of various types of secondary inter-actions, of which the most frequent are 'weak' hydrogen bonds from methine hydrogen atoms to the halogenido ligands. For the structure type 1a, H⋯X and H⋯E contacts combine to form a layer structure. For 3a/3b, the packing is almost featureless, but can be described in terms of a double-layer structure involving borderline H⋯Cl/Br and H⋯S contacts. In 4a and 4b/8b, which lack methine groups, Cmeth-yl-H⋯X contacts combine to form layer structures. In 7a/7b, short C-H⋯X inter-actions form chains of mol-ecules that are further linked by association of short Au⋯Se contacts to form a layer structure. The packing of compound 6b/6c can conveniently be analysed for each independent mol-ecule separately, because they occupy different regions of the cell. Mol-ecule 1 forms chains in which the mol-ecules are linked by a Cmethine⋯Au contact. The mol-ecules 2 associate via a short Se⋯Se contact and a short H⋯X contact to form a layer structure. The packing of compound 2c can be described in terms of two short Cmethine-H⋯I contacts, which combine to form a corrugated ribbon structure. Compound 7c is the only compound in this paper to feature Au⋯Au contacts, which lead to twofold-symmetric dimers. Apart from this, the packing is almost featureless, consisting of layers with only translation symmetry except for two very borderline Au⋯H contacts.

Crystal structures of five gold(I) complexes with methyl-piperidine ligands.

In bis-(4-methyl-piperidine-κN)gold(I) chloride, [Au(C6H13N)2]Cl (1), the methyl groups are, as expected, equatorial at the piperidine ring, but the Au atom is axial; this is the case for all five structures reported here, as is the expected linear coordination at the Au atom. Hydrogen bonding of the form N-H⋯Cl-⋯H-N leads to inversion-symmetric dimers, which are further connected by C-H⋯Au contacts. Bis(4-methyl-piperidine-κN)gold(I) di-chlorido-aurate(I), [Au(C6H13N)2][AuCl2] (2), also forms inversion-symmetric dimers; these involve aurophilic inter-actions and three-centre hydrogen bonds of the form NH(⋯Cl)2. Bis(4-methyl-piperidine-κN)gold(I) di-bromido-aurate(I), [Au(C6H13N)2][AuBr2] (3), is isotypic to 2. The 1:1 adduct chlorido-(4-methyl-piperidine-κN)gold(I) bis-(4-methyl-piperidine-κN)gold(I) chloride, [Au(C6H13N)2]Cl·[AuCl(C6H13N)] (4), crystallizes as its di-chloro-methane solvate. The asymmetric unit contains two formula units, in each of which the chloride anion accepts a hydrogen bond from the cation and from the neutral mol-ecule, and the two Au atoms are linked via an aurophilic inter-action. A further hydrogen bond leads to inversion-symmetric dimers. The asymmetric unit of bis-(2-methyl-piperidine-κN)gold(I) chloride, [Au(C6H13N)2]Cl (5), contains two 'half' cations, in which the Au atoms lie on twofold axes, and a chloride ion on a general position. Within each cation, the relative configurations at the atoms N and C2 (which bears the methyl substituent) are R,S. The twofold-symmetric dimer involves two N-H⋯Cl-⋯H-N units and an aurophilic contact between the two Au atoms.

An unexpected tautomer: synthesis and crystal structure of N-[6-amino-4-(methyl-sulfan-yl)-1,2-di-hydro-1,3,5-triazin-2-yl-idene]benzenesulfonamide.

The title compound, C10H11N5O2S2, consists of an unexpected tautomer with a protonated nitro-gen atom in the triazine ring and a formal exocyclic double bond C=N to the sulfonamide moiety. The ring angles at the unsubstituted nitro-gen atoms are narrow, at 115.57 (12) and 115.19 (12)°, respectively, whereas the angle at the carbon atom between these N atoms is very wide, 127.97 (13)°. The inter-planar angle between the two rings is 79.56 (5)°. The mol-ecules are linked by three classical hydrogen bonds, forming a ribbon structure. There are also unusual linkages involving three short contacts (< 3 Å) from a sulfonamide oxygen atom to the C-NH-C part of a triazine ring.

Crystal structures of five halido gold complexes involving piperidine or pyrrolidine as ligands or (protonated) as cations.

In bromido-(pyrrolidine-κN)gold(I) bis-(pyrrolidine-κN)gold(I) bromide, [AuBr(pyr)]·[Au(pyr)2]Br (pyr = pyrrolidine, C4H9N), 2, alternating [AuBr(pyr)] mol-ecules and [Au(pyr)2]+ cations are connected by aurophilic contacts to form infinite chains of residues parallel to the b axis. The chains are cross-linked by three N-H⋯Br- hydrogen bonds and an Au⋯Br contact to form a layer structure parallel to the ab plane. Tri-chlorido-(piperidine-κN)gold(III), [AuCl3(pip)] (pip = piperidine, C5H11N), 3, consists of mol-ecules with the expected square-planar coordination at the gold atom, which are connected by an N-H⋯Cl hydrogen bond and an Au⋯Cl contact to form a layer structure parallel to the ac plane. The structures of bis-(piperidinium) tetra-chlorido-aurate(III) chloride, (pipH)2[AuCl4]Cl, 4, and bis-(pyrrolidinium) tetra-bromido-aurate(III) bromide, (pyrH)2[AuBr4]Br, 6, are closely related but not isotypic. Compound 6 crystallizes in space group Ibam; the Au and two Br atoms of the anion lie in the mirror plane x, y, 0, whereas the bromide ions occupy special positions 0, 0.5, 0 and 0, 0.5, 0.25, with site symmetry 2/m. The NH2 group forms a hydrogen bond to one bromide ion, and also a three-centre hydrogen bond to the other bromide atom and to a metal-bonded Br atom. The packing involves chains of hydrogen-bonded pyrrolidinium and bromide ions parallel to the c axis, combined with a layer structure of [AuBr4]- and bromide anions, parallel to the ab plane and involving Au⋯Br and Br⋯Br contacts. Compound 4, however, crystallizes pseudosymmetrically in space group Iba2; two chlorine atoms of the anion lie on the twofold axis 0.5, 0.5, z, and there are two independent cations. The packing is closely similar to that of 6, but there are no N-H⋯Cl hydrogen bonds to metal-bonded chlorines. The contact distances Au⋯Cl are appreciably longer than their Au⋯Br counterparts in 6, whereas the Cl⋯Cl contact is much shorter than Br⋯Br in 6. Tri-bromido-(piperidine-κN)gold(III) crystallizes as its di-chloro-methane solvate, [AuBr3(pip)]·CH2Cl2, 7. It too displays a square-planar coordination at the gold atom. The packing involves hydrogen bonds N-H⋯Br, stacking of neighbouring AuBr3 units by Au⋯Br contacts, and a short Br⋯Br contact; these combine to form a layer structure parallel to the ac plane.

Synthesis of the indeno[1,2-b]indole core of janthitrem B.

The tetracyclic core structure of the majority of indole diterpenoids features a trans-hydrindane moiety that is fused to an indole unit. We report here a novel synthetic route that includes a photo-Nazarov cyclization of a 3-acylindole precursor initially providing the thermodynamically preferred cis-hydrindanone. After reduction and conversion to the cyclopentadiene, dihydroxylation and hydrogenation provided the indoline. The key step generated the trans-system by stereospecific hydride shift on a dioxaphospholane under Grainger's conditions, for the first time applied to an N-heterocycle. When starting from the corresponding indole, we observed the formation of hitherto unknown methanocyclohepta[b]indolones. Deoxygenation of the trans-hydrindanone was achieved after conversion to the 1,3-dithiolane, followed by RANEY® Ni reduction.

Access to isoindole-derived BODIPYs by an aminopalladation cascade.

Here, we present a new route to dyes of the BODIPY family. We first built up a N-Boc-protected dipyrromethene scaffold via an aminopalladation cascade. Subsequentially, the pyrrole moiety was deprotected and the BF2 unit inserted. Depending on the terminating reaction, BODIPYs with either aryl or alkynyl moieties were accessible.

Emergency department crowding is not being caused by increased inappropriate presentations.

Contrary to the prevailing wisdom, there may be little or no room to move with respect to reducing emergency department (ED) utilisation, as ED utilisation in Aotearoa New Zealand is low by world standards and is not driven by patients presenting inappropriately with minor conditions. We should continue the excellent work done in the primary care sector to maintain our low ED presentation rate and support primary and urgent care providers to provide alternatives to the ED for people with minor conditions. However, to reduce the system pressure and harms caused by ED crowding due to access block for admitted patients, we also need to adequately resource our hospital-based inpatient teams and EDs so that the (appropriate) acute care workload can be managed safely.

Crystal structure of 2-{[5-(methyl-sulfan-yl)-4-phenyl-4H-1,2,4-triazol-3-yl]meth-yl}benzo[d]thia-zole.

In the structure of the title compound, C17H14N4O2, the triazole ring exhibits inter-planar angles of 63.86 (2) and 76.96 (2)° with the phenyl and benzo-thia-zole planes, respectively. The C-C-C angle at the methyl-ene group is rather wide at 114.28 (4)°. The packing involves three borderline C-H⋯N contacts, two of which combine to form layers parallel to ac, and a pairing of the triazole rings across an inversion centre [inter-planar distance of 3.1852 (2) Å].

Crystal structure of 5-(ß-d-gluco-pyran-osyl-thio)-N-(4-methyl-phen-yl)-1,3,4-thia-diazol-2-amine.

In the structure of the title compound, C15H19N3O5S2, the bond lengths at the linking sulfur atom are significantly different [1.7473 (17) and 1.811 (2) Å], and the angle at the exocyclic nitro-gen atom is wide at 128.45 (18)°. The inter-planar angle between the tolyl and thia-diazole rings is 9.2 (1)°. The complex hydrogen-bonding pattern, involving five donors and five acceptors, can be broken down into a one-dimensional ribbon parallel to the b axis, involving hydrogen bonds of the sugar residues only, and a two-dimensional layer structure parallel to the ab plane, based on the N-H⋯O and O-H⋯N hydrogen bonds.

[2.2]Paracyclophane Derivatives as Building Blocks for Coordination Polymers.

Several new di- and tetracarboxylic [2.2]paracyclophane derivatives were obtained via Suzuki coupling between the appropriately brominated [2.2]paracyclophanes and 4-(methoxycarbonyl)phenylboronic acid. The reaction of one of these products, namely pp-bis(4-carboxyphenyl)[2.2]paracylophane (12), with zinc nitrate afforded a 2D coordination polymer comprising zinc-carboxylate paddlewheel clusters linked together by cyclophane cores. The zinc center is five-coordinated in a square-pyramidal geometry, with a DMF oxygen atom at the apex and four carboxylate oxygen atoms in the base.