Highly Regioselective Tandem Reaction of Ene-Yne-Oxazolones Induced by H-Phosphonates: Construction of Phosphinylindane Derivatives.

A highly regioselective divergent approach for the phosphine-containing indane/indene derivatives from the ene-yne-oxazolone precursors was reported. An insight into the reaction mechanism involving the phospha-1,4-addition followed by 5-exo-dig ring closure with a concomitant C-P/C-C bond formation was also proposed. This promising protocol utilized H-phosphonate as the phosphonating reagent in a silver-catalyzed or base-mediated cascade cyclization to construct the corresponding phosphorylated spiroindenoxazolones and amidoindenes, respectively, in good yields (up to 88% yield).

Drastic effect of lattice propionitrile molecules on the spin-transition temperature of a 2,2'-dipyridylamino/s-triazine-based iron(II) complex.

Reaction of iron(II) selenocyanate (obtained from Fe(ClO4)2 and KNCSe) with 2-(N,N-bis(2-pyridyl)amino)-4,6-bis(pentafluorophenoxy)-(1,3,5)triazine (L1(F)) in propionitrile produces the compound [Fe(L1(F))2(NCSe)2]·2CH3CH2CN (1(NCSe)·2PrCN), which shows spin-crossover (SCO) properties characterized by a T(1/2) of 283 K and a ΔT80 (i.e., temperature range within which 80% of the transition considered occurs) of about 65 K. Upon air exposure, 1(NCSe)·2PrCN gradually converts to a new SCO species that exhibits different properties, as reflected by T(1/2) = 220 K and ΔT80 = 70 K. Various characterization techniques, namely, IR spectroscopy, thermogravimetric analysis, and thermodiffractometric studies, reveal that the new phase is obtained through the loss of the lattice propionitrile molecules within several days upon air exposure or several hours upon heating above 390 K.

Crystal structure of a two-dimensional grid-type iron(II) coordination polymer: poly[[di-aqua-tetra-µ-cyanido-diargentate(I)iron(II)] trans-1,2-bis(pyridin-2-yl)ethyl-ene disolvate].

In the title compound, {[Ag2Fe(CN)4(H2O)2]·2C12H10N2} n , the asymmetric unit contains one Fe(II) cation, two water mol-ecules, two di-cyanido-argentate(I) anions and two uncoordinating 1,2-bis-(pyridin-2-yl)ethyl-ene (2,2'-bpe) mol-ecules. Each Fe(II) atom is six-coordinated in a nearly regular octa-hedral geometry by four N atoms from di-cyanido-argentate(I) bridges and two coordinating water mol-ecules. The Fe(II) atoms are bridged by di-cyanido-argentate(I) units to give a two-dimensional layer with square-grid spaces. The inter-grid spaces with inter-layer distance of 6.550 (2) Šare occupied by 2,2'-bpe guest mol-ecules which form O-H⋯N hydrogen bonds to the host layers. This leads to an extended three-dimensional supra-molecular architecture. The structure of the title compound is compared with some related compounds containing di-cyanido-argentate(I) ligands and N-donor organic co-ligands.

Hetero triply-bridged dinuclear copper(II) compounds with ferromagnetic coupling: a challenge for current density functionals.

Seven new hetero triply-bridged dinuclear Cu(II) compounds have been synthesized and characterized corresponding to a series with general formula [Cu(2)(L)(2)(µ-OH)(µ-OH(2))(µ-O(2)CR)]X(2) (where L = bpy = 2,2'-bipyridine, 4,4'-dmbpy = 4,4'-dimethyl-2,2'-bipyridine and 5,5'-dmbpy = 5,5'-dimethyl-2,2'-bipyridine; R = H for formate, CH(3) for acetate, CH(2)CH(3) for propionate and C(CH(3))(3) for trimethylacetate and X = CF(3)SO(3)(-) and ClO(4)(-)). All compounds exhibit ferromagnetic behavior with the experimental J values derived from magnetic susceptibility measurements being in the 73-104 cm(-1) range. The overall qualitative behavior is reproduced by state of the art density functional theory based methods. However, none of the functionals is able to reproduce the fine details along the series which constitutes an excellent benchmark for future developments.

The heterometallic cadmium-silver complex cis-bis[dicyanidoargentato(I)-κN]bis(5,5'-dimethyl-2,2'-bipyridyl-κ(2)N,N')cadmium(II) monohydrate.

In the title complex, [Ag2Cd(CN)4(C12H12N2)2]·H2O or cis-[Cd{Ag(CN)2}2(5,5'-dmbpy)2]·H2O, where 5,5'-dmbpy is 5,5'-dimethyl-2,2'-bipyridyl, the asymmetric unit consists of a discrete neutral [Cd{Ag(CN)2}2(5,5'-dmbpy)2] unit and a solvent water molecule. The Cd(II) cation is coordinated by two bidentate chelate 5,5'-dmbpy ligands and two monodentate [Ag(I)(CN)2](-) anions, which are in a cis arrangement around the Cd(II) cation, leading to an octahedral CdN6 geometry. The overall structure is stabilized by a combination of intermolecular hydrogen bonding, and Ag(I)···Ag(I) and π-π interactions, forming a three-dimensional supramolecular network.

Di-µ-acetato-κ(4) O:O'-bis-[(1,10-phenanthroline-κ(2) N,N')(tri-fluoro-methane-sulfonato-κO)copper(II)].

The complete molecule of the title compound, [Cu2(C2H3O2)2(CF3O3S)2(C12H8N2)2], is completed by the application of a twofold rotation and comprises two Cu(II) ions, each of which is penta-coordinated by two N atoms from a bidentate 1,10-phenanthroline (phen) ligand, two O atoms from acetate ligands and an O atom from a tri-fluoro-methane-sulfonate anion, forming a (4 + 1) distorted square-pyramidal coordination geometry. The Cu(II) ions are connected by two acetate bridges in a syn-syn configuration. The F atoms of the tri-fluoro-methane-sulfonate ligands are disordered, with site-occupation factors of 70 and 30. The molecular structure is stabilized by intra-molecular face-to-face π-π inter-actions with centroid-centroid distances in the range 3.5654 (12)-3.8775(12) Å. The crystal structure is stabilized by C-H⋯O interactions, leading to a three-dimensional lattice structure.

Crystal structure and Hirshfeld surface analysis of a new mononuclear copper(II) complex: [bis-(pyridin-2-yl-κN)amine](formato-κO)(m-hy-droxy-benzoato-κ2O,O')copper(II).

A new mononuclear copper(II) complex, [Cu(C7H5O3)(HCO2)(C10H9N3)], containing mixed N- and O-donor ligands, 2,2'-di-pyridyl-amine (dpyam) and m-hy-droxy-benzoate (m-OHbenz), has been obtained from a solvent mixture. The coordination environment of the CuII ion is distorted square-pyramidal with a [N2O3] coordination set originating from the chelating dpyam and m-OHbenz ligands in the basal plane and the O atom of a formato ligand at the apical position. The crystal structure of the title complex is stabilized by N-H⋯O, O-H⋯O, C-H⋯O hydrogen-bonding, π-π and C-H⋯π inter-molecular inter-actions, which were qu-anti-fied by Hirshfeld surface analysis.

Phlegcarines A-C, three Lycopodium alkaloids from Phlegmariurus carinatus (Desv. ex Poir.) Ching.

Three undescribed Lycopodium alkaloids, phlegcarines A-C, along with nine known alkaloids, were isolated from the aerial parts of a gardening clubmoss Phlegmariurus carinatus (Desv. ex Poir.) Ching. Phlegcarine A is an undescribed Lycopodium alkaloid possessing an unprecedented 5/9/6/6 fused-tetracyclic ring system consisting of an oxa-cyclononanone, a piperidine, a methylcyclohaxane and an oxazolidine. Phlegcarine B is the first N-chloromethyl piperidinium Lycopodium alkaloid of (+)-lycoflexine. The semi-synthesis of phlegcarine B was investigated from (+)-fawcettimine. Phlegcarine C, an undescribed epimer of 12-epilycodoline, is a rare lycopodine-type alkaloid with ß-oriented H-4. Transformation of phlegcarine C and lycodoline to 12-epilycopodine N-oxide via keto-enol tautomerization was investigated using m-CPBA. The structural assignments were established through comprehensive spectroscopic techniques and chemical correlations. Phlegcarines A-C were assayed for their anti-acetylcholinesterase activity, but none of them exhibited biological activity more potent than that of huperzine A.

Synthesis and crystal structure of poly[[bis-(aqua-κO)tetra-kis-(µ-4,4'-bi-pyridine-κ2 N:N')hexa-kis-(3-chloro-benzoato)-κ5 O;κ2 O:O'-tricobalt(II)] methanol disolvate].

A novel ladder-chain cobalt(II) coordination polymer, {[Co3(C7H4ClO2)6(C10H8N2)4(H2O)2]·2CH3OH} n , was synthesized and characterized. The structure contains two CoII centres with different octa-hedral environments, [Co(1)N3O3] and [Co(2)N2O4]. The O-donating 3-chloro-benzoate anions (3-Clbenz) act as the terminal ligands, while the N-donating 4,4'-bipy mol-ecules play the role of linkers. The Co(1) ions are linked by 4,4'-bipy mol-ecules into linear chains. Two such chains are joined by [Co(2)(3-Clbenz)2(H2O)2] units via two 4,4'-bipy bridging ligands, thus forming the ladder-chain structure. The crystal packing of the title compound is stabilized by supra-molecular inter-actions, such as hydrogen bonding, π-π and halogen⋯π contacts, giving a three-dimensional framework. The spectroscopic and thermal properties of the title compound have also been investigated.

Crystal structure of catena-poly[[[bis-(1-benzyl-imidazole-κN)copper(II)]-µ-sulfato-κ2 O:O'-[tetra-kis-(1-benzyl-imidazole-κN)copper(II)]-µ-sulfato-κ2 O:O'] N,N-di-methyl-formamide disolvate dihydrate].

The title one-dimensional copper(II) coordination polymer, {[Cu(SO4)(C10H10N2)3]·C3H7NO·H2O} n or {[Cu(bzi)3(µ-O2SO2)]·H2O·DMF} n (bzi = 1-benz-yl-imidazole, C10H10N2; DMF = N,N-di-methyl-formamide, C3H7NO), is constructed by monodentate bzi ligands and bridging sulfate anions, leading to chains propagating parallel to the c axis. Within a chain, there are two crystallographic independent CuII ions, each with site symmetry , which form [CuN2O2] and [CuN4O2] polyhedra alternating along the chain direction. The crystal structure is consolidated by weak hydrogen-bonding, C-H⋯π and π-π inter-actions, leading to the formation of a three-dimensional supra-molecular network.

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.

Toward the design of ferromagnetic molecular complexes: magnetostructural correlations in ferromagnetic triply bridged dinuclear Cu(II) compounds containing carboxylato and hydroxo bridges.

In the present work we present a comprehensive study of the magneto-structural correlations of a series of ferromagnetic triply heterobridged Cu(II) dinuclear compounds containing [Cu(2)(mu-O(2)CR)(mu-OH)(mu-X)(L)(2)](2+) ions (where X = OH(2), Cl(-), OMe(-) and L = bpy, phen, dpyam) which have the particularity of being all ferromagnetic. The present theoretical study, based on hybrid density functional theory (DFT) calculations, leads to strong conclusions about the role of the pentacoordination geometry of the Cu(II) ions (square base pyramidal (SP) or trigonal bipyramidal (TBP) coordination) and the nature of the third bridging ligand in determining the final value of the magnetic coupling constants in this series of compounds. These investigations point toward the existence of a maximum value for the ferromagnetic interaction and may offer some useful information to synthetic chemists aiming at obtaining new compounds with enhanced ferromagnetism.

Crystal structure of a novel one-dimensional zigzag chain-like cobalt(II) coordination polymer constructed from 4,4'-bi-pyridine and 2-hy-droxy-benzoate ligands.

A novel one-dimensional zigzag chain-like CoII coordination polymer constructed from 4,4'-bi-pyridine (4,4'-bpy) and 2-hy-droxy-benzoate (2-OHbenz) ligands, namely, catena-poly[[(4,4'-bi-pyridine-κN)-(µ-2-hy-droxy-benzoato-κ2 O:O')(2-hy-droxy-benzoato-κ2 O,O')cobalt(II)]-µ-4,4'-bi-pyridine-κ2 N:N'-[aquahemi(µ-4,4'-bi-pyridine-κ2 N:N')(2-hy-droxy-benzoato-κO(2-hy-droxy-benzoato-κ2 O:O')cobalt(II)], [Co2(C7H5O3)4(C10H8N2)2.5(H2O)] n , has been synthesized by reacting cobalt(II) nitrate trihydrate, 4,4'-bpy and 2-hy-droxy-benzoic acid in a mixture of water and methanol at room temperature. There are two independent CoII centers, Co1 and Co2, in the asymmetric unit, revealing a distorted octa-hedral geometry with chromophore types of [CoN2O4] and [CoN2O3O'], respectively. The Co1 ions are doubly bridged by 2-OHbenz ligands with syn-anti coordination mode, generating a dinuclear unit. The bridging 4,4'-bpy ligands connect these dinuclear units and the mononuclear Co2 chromophores, providing a one-dimensional alternating zigzag chain-like structure. In the crystal, inter-molecular hydrogen bonds, C-H⋯π and π-π stacking inter-actions are observed and these help to consolidate the packing. In addition, the physical properties of the title compound are reported.

Crystal structures and Hirshfeld surface analysis of trans-bis-(thio-cyanato-κN)bis-{2,4,6-trimethyl-N-[(pyridin-2-yl)methyl-idene]aniline-κ2 N,N'}manganese(II) and trans-bis-(thio-cyanato-κN)bis-{2,4,6-trimethyl-N-[(pyridin-2-yl)methyl-idene]aniline-κ 2 N,N'}nickel(II)).

Two new mononuclear metal complexes involving the bidentate Schiff base ligand 2,4,6-trimethyl-N-[(pyridin-2-yl)methyl-idene]aniline (C15H16N2 or PM-TMA), [Mn(NCS)2(PM-TMA)2] (I) and [Ni(NCS)2(PM-TMA)2] (II), were synthesized and their structures determined by single-crystal X-ray diffraction. Although the title compounds crystallize in different crystal systems [triclinic for (I) and monoclinic for (II)], both asymmetric units consist of one-half of the complex mol-ecule, i.e. one metal(II) cation, one PM-TMA ligand, and one N-bound thio-cyanate anion. In both complexes, the metal(II) cation is located on a centre of inversion and adopts a distorted octa-hedral coordination environment defined by four N atoms from two symmetry-related PM-TMA ligands in the equatorial plane and two N atoms from two symmetry-related NCS- anions in a trans axial arrangement. The tri-methyl-benzene and pyridine rings of the PM-TMA ligand are oriented at dihedral angles of 74.18 (7) and 77.70 (12)° for (I) and (II), respectively. The subtle change in size of the central metal cations leads to a different crystal packing arrangement for (I) and (II) that is dominated by weak C-H⋯S, C-H⋯π, and π-π inter-actions. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to qu-antify these inter-molecular contacts, and indicate that the most significant contacts in packing are H⋯H [48.1% for (I) and 54.9% for (II)], followed by H⋯C/C⋯H [24.1% for (I) and 15.7% for (II)], and H⋯S/S⋯H [21.1% for (I) and 21.1% for (II)].

Crystal structure and photoluminescence properties of catena-poly[[bis-(1-benzyl-1H-imidazole-κN 3)cadmium(II)]-di-µ-azido-κ4 N 1:N 3].

The new title one-dimensional CdII coordination polymer, [Cd(C10H10N2)2(µ1,3-N3)2] n , has been synthesized and structurally characterized by single-crystal X-ray diffraction. The asymmetric unit consists of a CdII ion, one azide and one 1-benzyl-imidazole (bzi) ligand. The CdII ion is located on an inversion centre and is surrounded in a distorted octa-hedral coordination sphere by six N atoms from four symmetry-related azide ligands and two symmetry-related bzi ligands. The CdII ions are linked by double azide bridging ligands within a µ1,3-N3 end-to-end (EE) coordination mode, leading to a one-dimensional linear structure extending parallel to [100]. The supra-molecular framework is stabilized by the presence of weak C-H⋯N inter-actions, π-π stacking [centroid-to-centroid distance of 3.832 (2) Å] and C-H⋯π inter-actions between neighbouring chains.

Crystal structure and Hirshfeld surface analysis of bis-(benzoato-κ2 O,O')[bis-(pyridin-2-yl-κN)amine]nickel(II).

A new mononuclear NiII complex with bis-(pyridin-2-yl)amine (dpyam) and benzoate (benz), [Ni(C7H5O2)2(C10H9N3)], crystallizes in the monoclinic space group P21/c. The NiII ion adopts a cis-distorted octa-hedral geometry with an [NiN2O4] chromophore. In the crystal, the complex mol-ecules are linked together into a one-dimensional chain by symmetry-related π-π stacking inter-actions [centroid-to-centroid distance = 3.7257 (17) Å], along with N-H⋯O and C-H⋯O hydrogen bonds. The crystal packing is further stabilized by C-H⋯π inter-actions, which were investigated by Hirshfeld surface analysis.

Crystal structure of poly[di-aqua-bis-(µ5-benzene-1,3-di-carboxyl-ato)(N,N-di-methyl-formamide)-cadmium(II)disodium(I)].

The title compound, [CdNa2(C8H4O4)2(C3H7NO)(H2O)2] n or [CdNa2(1,3-bdc)2(DMF)(H2O)2] n , is a new CdII-NaI heterobimetallic coordination polymer. The asymmetric unit consists of one CdII atom, two NaI atoms, two 1,3-bdc ligands, two coordinated water mol-ecules and one coordinated DMF mol-ecule. The CdII atom exhibits a seven-coordinate geometry, while the NaI atoms can be considered to be penta-coordinate. The metal ions and their symmetry-related equivalents are connected via chelating-bridging carboxyl-ate groups of the 1,3-bdc ligands to generate a three-dimensional framework. In the crystal, there are classical O-H⋯O hydrogen bonds involving the coordinated water mol-ecules and the 1,3-bdc carboxyl-ate groups and π-π stacking between the benzene rings of the 1,3-bdc ligands present within the frameworks.

A novel one-dimensional double-chain-like ZnII coordination polymer: poly[bis(1-benzyl-1H-imidazole-κN3)tris(µ-cyanido-κ2C:N)(cyanido-κC)disilver(I)zinc(II)].

One of most interesting systems of coordination polymers constructed from the first-row transition metals is the porous ZnII coordination polymer system, but the numbers of such polymers containing N-donor linkers are still limited. The title double-chain-like ZnII coordination polymer, [Ag2Zn(CN)4(C10H10N2)2]n, presents a one-dimensional linear coordination polymer structure in which ZnII ions are linked by bridging anionic dicyanidoargentate(I) units along the crystallographic b axis and each ZnII ion is additionally coordinated by a terminal dicyanidoargentate(I) unit and two terminal 1-benzyl-1H-imidazole (BZI) ligands, giving a five-coordinated ZnII ion. Interestingly, there are strong intermolecular AgI...AgI interactions between terminal and bridging dicyanidoargentate(I) units and C-H...π interactions between the phenyl rings of BZI ligands of adjacent one-dimensional linear chains, providing a one-dimensional linear double-chain-like structure. The supramolecular three-dimensional framework is stabilized by C-H...π interactions between the phenyl rings of BZI ligands and by AgI...AgI interactions between adjacent double chains. The photoluminescence properties have been studied.

Influence of supramolecular bonding contacts on the spin crossover behaviour of iron(II) complexes from 2,2'-dipyridylamino/s-triazine ligands.

Reactions of the related ligands 2-(N,N-bis(2-pyridyl)amino)-4,6-bis(phenoxy)-(1,3,5)triazine (L1) and 2-(N,N-bis(2-pyridyl)amino)-4,6-bis(pentafluorophenoxy)-(1,3,5)triazine (L1(F)) with iron(II) thiocyanate produced two spin-crossover coordination compounds with distinct cooperative behaviours. trans-[Fe(L1)2(NCS)2]·2CH2Cl2 (1) displays a very gradual transition centred at T½ = 233 K, characterized by a ΔT80 (namely the temperature range within which 80% of the transition considered occurs) of 90 K, while that of fluorinated trans-[Fe(L1(F))2(NCS)2]·2CH3CN (3) is significantly more abrupt (and centred at T½ = 238 K), with a ΔT80 of 50 K, resulting from supramolecular contacts induced by the fluorinated phenol groups. The coordination compound equivalent to 1 with selenocyanate anions, namely trans-[Fe(L1)2(NCSe)2]·4CH2Cl2·4CH3OH (2), also exhibits SCO properties centred at T½ = 238 K, but the transition is very gradual (ΔT80 = 150 K). Light-induced excited spin-state trapping (LIESST) is effective although incomplete for 2 and 3, while it is complete with a T(LIESST) of 58 K for 1.