New series of triply bridged dinuclear Cu(II) compounds: synthesis, crystal structure, magnetic properties, and theoretical study.

Five new triply bridged dinuclear Cu(II) compounds have been synthesized, and their magnetic properties have been measured and characterized. The magnetic coupling constants (J) of these compounds plus a previously structurally characterized compound of the same type have been derived by appropriate fitting of the experimentally measured molar susceptibility variation with the temperature. Two of the compounds are ferromagnetically coupled, and three are antiferromagnetically coupled with J values in the [+150, -40] cm(-1) range. The validity of the structural aggregate Addison's parameter as a qualitative magneto-structural correlation is confirmed. The origin of the magnetic interactions and the magnitude of the magnetic coupling have been analyzed by means of density functional theory-based calculations using a variety of state of the art exchange-correlation potentials. It is shown that the long-range separated LC-ωPBE provides the overall best agreement with experiment for this family as well as for a set of previously reported hetero triply bridged dinuclear Cu(II) compounds, especially for ferromagnetic systems.

Spin canting and metamagnetism in 2D and 3D cobalt(II) coordination networks with alternating double end-on and double end-to-end azido bridges.

By employing an N,N'-ditopic spacer 2-aminopyrazine (ampyz), two-dimensional (2D) (1) and three-dimensional (3D) (2) azido-bridged cobalt(II) coordination networks with the identical formula [Co(N(3))(2)(ampyz)](n) have been synthesized and characterized structurally and magnetically. Compound 1 was prepared by the layer diffusion method in ambient temperature and crystallized in the high symmetric space group Immm. The 2D square-grid structure of 1 contains the perfect symmetric linear of alternating double end-on (EO) and double end-to-end (EE) azido-bridged Co(II) chains which are linked together by an ampyz spacer in trans-arrangement. The intralayer π-π stacking interactions among ampyz spacers additionally stabilize this layer. The adjacent 2D layers are assembled by the intermolecular hydrogen bonding between the NH(2) of the ampyz and the EE azido ligands building a 3D structure. Compound 2 was prepared by a hydrothermal technique and shows a 3D framework containing a zigzag chain of similarly alternating double EO and double EE azido-bridged Co(II) center. In contrast, this chain is linked by two ampyz spacers in cis-fashion giving rise to a 3D structure. The magnetic investigation of 1 shows the coexistence of a big spin canting angle and metamagnetism having magnetic ordering at 10 K, whereas the magnetic behavior of 2 simply exhibits spin-canted antiferromagnetism below T(N) of 16 K.

Diazido-bis-(5,5'-dimethyl-2,2'-bipyridyl-κN,N')cobalt(II) monohydrate.

In the title compound, [Co(C(12)H(12)N(2))(2)(N(3))(2)]·H(2)O, the Co(II) ion is situated on a crystallographic twofold axis and adopts a distorted octa-hedral geometry with the two dmbpy (dmbpy = 5,5'-dimethyl-2,2'-bipyrid-yl) and the two azido ligands in a cis arrangement. The solvent water mol-ecule and one methyl group of the dmbpy ligand are disordered over two sets of sites in a 1:1 ratio. The crystal structure is stabilized by intra-molecular C-H⋯N(dmbpy) and inter-molecular O-H⋯N(azide) hydrogen bonds.

Water-induced reversible structural phase transformation with chromotropism in metal supramolecular frameworks containing aminopyrazine and sulfate anions.

Three new supramolecular metal-coordination architectures [M(H2O)4(ampyz)2][M(H2O)6](SO4)2(H2O)2 (M = Co (1), Fe (2), and mixed Co/Fe (3); ampyz = 2-aminopyrazine) and a Cd(II) coordination polymer [Cd(ampyz)(H2O)2(SO4)]n(H2O)n (4) were synthesized by layered diffusion and structurally characterized. Compounds 1-3 are isomorphous. Monomeric complex units [M(H2O)4(ampyz)2]2+ are assembled by intermolecular hydrogen bonding and pi-pi stacking via ampyz moieties to build 2D sheets. These layers are linked by intermolecular hydrogen bonding via ampyz ligand, [M(H2O)6]2+ unit, sulfate anion and lattice and coordinated water molecules to stabilize 3D supramolecular structure. Compound 4 shows a 2D coordination network where the sulfato connector and the bridging ampyz link Cd(II) ions. Lattice water molecules are filled in between the layers via the hydrogen bonds stabilizing 3D supramolecular network of 4. Interestingly, compounds 1-3 exhibit water-induced reversible crystal-to-amorphous transformations with chromotropism and compound 4 also shows water-induced reversible structural phase transformation confirmed by spectroscopic techniques, elemental analyses, TGA, and XRPD. These results demonstrate the significant role between coordination bridges and weaker intermolecular interactions for the structural conversion even though 1-3 lack coordination bridges for the maintenance of their structures, however, the weak intermolecular interactions, especially hydrogen bonding, play a key role to the recovery of the crystalline phase.

Biotransformation of ent-kaur-16-en-19-oic acid by Absidia blakesleeana and Rhizopus oligosporus.

Biotransformation of ent-kaur-16-en-19-oic acid was carried out with Absidia blakesleeana and Rhizopus oligosporus. Absidia blakesleeana produced two novel metabolites, ent-(7alpha, 9alpha)-dihydroxy-kaur-16-en-19-oic acid and ent-(1beta, 7alpha)-dihydroxy-kaur-16-en-19-oic acid, together with three known compounds: ent-7alpha-hydroxy-kaur-16-en-19-oic acid, ent-(7alpha, 11beta)-dihydroxy-kaur-16-en-19-oic acid and ent-(7alpha, 13)-dihydroxy-kaur-16-en-19-oic acid. The ent-7alpha-hydroxy-kaur-16-en-19-oic acid and ent-(7alpha, 9alpha)-dihydroxy-kaur-16-en-19-oic acid were obtained from R. oligosporus. The structures were established by spectroscopic techniques and X-ray crystallography.

Biotransformation of ent-kaur-16-en-19-oic acid by Psilocybe cubensis.

Biotranformation of ent-kaur-16-en-19-oic acid (1) using Psilocybe cubensis resulted in hydroxylated products. After two days of incubation, ent-16beta,17-dihydroxy-kauran-19-oic acid (2) was isolated. After further incubation for nine days, two novel metabolites, ent-12alpha,16beta,17-trihydroxy-kauran-19-oic acid (3) and ent-11alpha,16beta,17-trihydroxy-kauran-19-oic acid (4), were obtained. The metabolites were identified by spectroscopic methods and X-ray crystallography. Compounds 1-4 were evaluated for their cytotoxic properties against the human leukaemia K562 cell line; only compound 1 showed moderate activity.

Spectroscopy and structures of two complete families, one mononuclear, the other binuclear, of 1 : 2 CuX : dptu stoichiometry (X = Cl, Br, I; 'dptu' = N,N'-diphenylthiourea).

Crystallization of the copper(i) halides (CuX; X = Cl, Br, I) with N,N'-diphenylthiourea ('dptu' = (PhNH)(2)CS) in 1 : 2 ratio from acetonitrile solution in ambient conditions yields a mononuclear isomorphous series of complexes of the form [XCu(dptu)(2)].H(2)O, an unusually complete array, with the central copper atoms in quasi-trigonal planar environments, as shown by single crystal X-ray studies, in turn providing a platform for comparative spectroscopic studies. Under anhydrous conditions, anhydrous compounds may be obtained, a full series again being accessible, but now of the binuclear form [(dptu)XCu(mu-S-dptu)(2)CuX(dptu)], the chloride being a bis(acetonitrile) solvate, the isomorphous bromide and iodide pair being unsolvated. A (solvated) sulfate salt is found to be of the form [Cu(dptu)(2)](2)(SO(4)), providing a novel example of a copper(i) atom being (quasi-)linearly coordinated by the pair of unidentate (dptu) sulfur ligands, Cu-S 2.1770(5), 2.1811(5) A, S-Cu-S 162.18(2) degrees . The nu(CuX) vibrational frequencies are assigned in the far-IR spectra of [XCu(dptu)(2)].H(2)O (X = Cl, Br, I) at 274, 207, and 190 cm(-1) respectively. The broadline static (65)Cu NMR spectra of [Cl(2)Cu(2)(dptu)(4)].2CH(3)CN and [X(2)Cu(2)(dptu)(4)] (X = Br, I) have been recorded at 9.4 and 7.05 T, and the spectra have been analysed to yield the (65)Cu nuclear quadrupole coupling and chemical shift parameters. The (63,65)Cu nuclear quadrupole resonance frequencies of [XCu(dptu)(2)].H(2)O (X = Cl, Br, I) have also been measured, and the resulting (65)Cu quadrupole coupling constants are ca. 4x those of the dimeric [X(2)Cu(2)(dptu)(4)] compounds.

A new sesquiterpenoid metabolite from Psilocybe samuiensis.

A novel 2,3-secoaromadendrane-type sesquiterpenoid metabolite, psilosamuiensin A (1), was isolated from the broth of Psilocybe samuiensis. The structure of psilosamuiensin A was established by spectroscopic data and its configurations were confirmed by single crystal X-ray crystallographic analysis. This is the first report of psilosamuiensin A found in the genus Psilocybes.

Diazido-bis(5,5'-dimethyl-2,2'-bipyridyl-κN,N')nickel(II) monohydrate.

In the crystal structure of the title compound, [Ni(N(3))(2)(C(12)H(12)N(2))(2)]·H(2)O, the Ni(II) atom is situated on a twofold axis and adopts a distorted octa-hedral geometry with the two 5,5'-dimethyl-2,2'-bipyridyl (dmbpy) and the two azide ligands in a cis arrangement. The water solvent mol-ecule is disordered over two positions in a 1:1 ratio.

9-Meth-oxy-6a,11a-dimethyl-6a,11a-dihydro-6H-1-benzofuro[3,2-c]chromen-3-ol from Dalbergia oliveri.

The title compound, commonly known as (+)-(6aS,11aS)-medicarpin, C(16)H(14)O(4), was isolated from Dalbergia oliveri and displays a rigid mol-ecule consisting of four fused rings. The benzofuran system is inclined at an angle of 76.49 (2)° with respect to the chroman unit. The compound exists as a polymeric chain arising from inter-molecular O-H⋯O bonding.

8-[(3,3-Dimethyl-oxiran-2-yl)methoxy-meth-yl]-11-hydr-oxy-2-isopropenyl-5-methyl-12-oxo-1,2,3,12-tetra-hydro-pyrano[3,2-a]xanthen-1-yl acetate.

The title compound, commonly known as 14-methoxy-tajixanthone-25-acetate, C(28)H(30)O(8), was isolated from Emericella variecolor. The central xanthone core is approximately planar (r.m.s. deviation = 0.084 Å). The dihydro-pyran ring adopts a distorted half-chair conformation. The oxirane plane is oriented at an angle of 63.3 (2)° with respect to the phenol group. An intra-molecular O-H⋯O hydrogen bond forms an S(6) ring. In the crystal, mol-ecules are linked into a two-dimensional network parallel to the ab plane by weak inter-molecular C-H⋯O hydrogen bonds.

Di-µ(4)-succinato-tetra-kis[aqua-phenanthrolinecopper(II)] tetra-nitrate tetra-hydrate.

In the title compound, [Cu(4)(C(4)H(4)O(4))(2)(C(12)H(8)N(2))(4)(H(2)O)(4)](NO(3))(4)·4H(2)O, the complete tetra-cation is generated by crystallographic inversion symmetry. Both unique Cu(2+) ions are coordinated by an N,N'-bidentate phenanthroline mol-ecule, two O-monodentate bis-bridging succinate dianions and a water mol-ecule, resulting in distorted CuN(2)O(3) square-based pyramidal geometries for the metal ions, with the water mol-ecule occupying the apical site. In the crystal, the components are linked by O-H⋯O hydrogen bonds and aromatic π-π stacking inter-actions [minimum centroid-centroid separation = 3.537 (2) Å].

Polymorphism in beta-cyclodextrin-benzoic acid inclusion complex: a kinetically controlled crystal growth according to the Ostwald's rule.

Crystal form II of the beta-cyclodextrin-benzoic acid (beta-CD-BA) inclusion complex was obtained from the 1.5-year stored aqueous EtOH solution of beta-CD and BA as 2beta-CD.1.5BA.0.7EtOH.21H(2)O in the monoclinic space group C2 with unit cell constants: a=19.413(3), b=24.306(4), c=32.975(1)A, beta=104.41(1) degrees . By contrast, the desired crystal form I in the triclinic space group P1 that ever grew up from the fresh solution as 2beta-CD.2BA.0.7EtOH.20.65H(2)O was not reproducible any more [Aree, T.; Chaichit, N. Carbohydr. Res.2003, 338, 439-446]. In the two crystal forms, beta-CDs are isostructural with a 'round' conformation stabilized by intramolecular O-3(n)cdots, three dots, centeredO-2(n+1) hydrogen bonds. The BA inclusion geometries are similar with a preferred orientation, that is, BAs are situated above the O-4 plane, point their COOH groups to the beta-CD O-6 side, incline 52 degrees with respect to the O-4 plane and are mainly maintained in positions by hydrogen bonding with the surrounding water molecules. beta-CDs form dimers as structural motif of different packing modes: the screw-channel type in form II and the average of intermediate and tetrad types in form I. Polymorphism in the beta-CD-BA inclusion complex is a kinetically controlled crystal growth following the Ostwald's rule: the less stable crystal form I grew up first within one week from the fresh solution, whereas the more stable crystal form II appeared after 1.5-year storage.

Conformation-selective synthesis and binding properties of N-benzylhexahomotriaza-p-chlorocalix[3]trinaphthylamide.

N-benzylhexahomotriaza-p-chlorocalix[3]trinaphthylamide in partial cone conformation was selectively synthesized by appropriately controlling the steric effect during the amidation reactions of N-benzylhexahomotriaza-p-chlorocalix[3]tri(ethyl acetate) in cone or partial cone conformations with use of 1-aminomethylnaphthalene. The conformation was confirmed by (1)H, (13)C, and 2D NMR and X-ray single-crystal analysis. Analyses of the complexes revealed that recognition is strongly affected by Cd(2+), Pb(2+), and F(-) ions.

Crystal form III of beta-cyclodextrin-ethanol inclusion complex: layer-type structure with dimeric motif.

The crystal form III of the beta-cyclodextrin (beta-CD)-ethanol inclusion complex [2(C(6)H(10)O(5))(7).1.5C(2)H(5)OH.19H(2)O] belongs to the triclinic space group P1 with unit cell constants: a=15.430(1), b=15.455(1), c=17.996(1)A, alpha=99.30(1) degrees , beta=113.18(1) degrees , gamma=103.04(1) degrees . beta-CD forms dimers comprising two identical monomers that adopt a 'round' conformation stabilized by intramolecular, interglucose O-3(n)cdots, three dots, centeredO-2(n+1) hydrogen bonds. The two beta-CD monomers of form III are isostructural to that of form I in the monoclinic space group P2(1) [Steiner, T.; Mason, S. A.; Saenger, W. J. Am. Chem. Soc.1991, 113, 5676-5687], but exhibit a striking difference from that of form II in the monoclinic space group C2 [Aree, T.; Chaichit, N. Carbohydr. Res.2003, 338, 1581-1589]. The small guest EtOH molecule orients differently in the large beta-CD cavity. In form III, two disordered EtOH molecules are embedded in the beta-CD-dimer cavity. A half occupied EtOH molecule (#1) is located above the O-4 plane of beta-CD #1, whereas another doubly disordered EtOH molecule (#2, #3) is situated at about the middle of the beta-CD-dimer cavity. The three EtOH sites are maintained in positions by making van der Waals contacts to each other and to the surrounding water sites and beta-CD O-3-H group. The EtOH molecules disordered (occupancy 0.3) above the beta-CD O-4 plane in form I and fully occupied beneath the O-4 plane in form II are strongly held in positions by hydrogen bonding with the surrounding water site and beta-CD O-6-H, O-3-H groups. Occurrence of the beta-CD dimer as a structural motif of channel-type packing (form II) and layer-type packing (form III) is attributed to the higher tendency for self aggregation under the moderate acidic conditions. At weak acidic conditions, beta-CD prefers a herringbone mode (form I).

Five-coordinate copper(II) complexes: crystal structures, spectroscopic properties and new extended structural pathways of [Cu(chelate)2X]Y, where chelate = dpyam, phen and bipy; X = pseudohalide ligands.

The crystal structures of four distortion isomers of the [Cu(chelate)(2)X](+) cation, where chelate = 2,2-bipyridine (bipy), 1,10-phenanthroline (phen) and di-2-pyridylamine (dpyam), X = a pseudohalide ligand (NCO, NCS, N(3) and C(2)N(3)), have been compared by scatterplot analysis with 25 [Cu(chelate)(2)X]Y complexes of known crystal structure. The four new complexes [Cu(phen)(2)NCO]Br (1), [Cu(phen)(2)N(3)]BPh(4).H(2)O (2), [Cu(dpyam)(2)(N(3))]NO(3).H(2)O (3) and [Cu(dpyam)(2)(N(3))]ClO(4) (4) involve a near regular square-based pyramidal stereochemistry (RSBP). The structures of complexes (1) and (2) are of the rare cases found for the phen analogue. Scatterplots of the 29 cation distortion isomers of the [Cu(chelate)(2)X]Y series of complexes suggest that most of the 29 complexes lie on a common structural pathway, involving a mixture of the symmetric, C(2), and the asymmetric, non-C(2), in-plane modes of vibration of the CuN(4)N' chromophore. Some datapoints are found to lie on extended routes The resulting structural pathways are consistent with the direct observation of the effect of the modes of vibration on the stereochemistries of the complexes. A comparison of the trends in the 29 datasets suggests a size effect of the phen, bipy and dpyam ligands.

Solvent-assisted mechanochemical synthesis of metal complexes.

The application of solvent-assisted mechanochemical synthesis to the study of metal complex formation is illustrated by examples involving complexes of silver halides with ethylenethiourea.

Antimalarial benzoquinones from an endophytic fungus, Xylaria sp.

Two novel benzoquinone metabolites, 2-chloro-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione ( 1) and xylariaquinone A ( 2) together with two known compounds were isolated from an endophytic fungus, Xylaria sp. Their structures were assigned by analysis of spectroscopic data, and the structures of 1 and 3 were also confirmed by single-crystal X-ray data. Compounds 1 and 2 showed in vitro activity against Plasmodium falciparum, K1 strain, with IC 50 values of 1.84 and 6.68 microM and cytotoxicity against African green monkey kidney fibroblasts (Vero cells) with IC 50 values of 1.35 and >184 microM, respectively.

Aqua(2,2'-bipyridyl)chloronitratocopper(II).

In a new hydrogen-bonded three-dimensional complex, [CuCl(NO3)(C10H8N2)(H2O)], the Cu atom has an elongated tetragonal octahedral environment, with two 2,2'-bipyridyl N atoms, one nitrate O atom and one Cl atom forming the equatorial plane, and a second O atom of the nitrate anion and a water molecule in the axial positions. The complex molecules are linked to form a three-dimensional supramolecular array by hydrogen-bonding interactions both between the water O atom and nitrate O atoms, and between the water O atom and the Cl atom of a neighboring molecule.