Synthesis and characterization of glycol-modified vanadium(V) oxoisopropoxide and their oximato derivatives: sol–gel transformations of [VO(OPr i )3], [VO{OCH2CH2OCH2CH2O}{OPr i }] and [VO{OCH2CH2OCH2CH2O}{ON=C(CH3)(C4H3S-2)}] to vanadia

Reaction of [VO(OPr ⁱ )₃] (1) with [O(CH₂CH₂OH)₂] in 1:1 molar ratio in anhydrous benzene yield glycol-modified precursor, [VO{OCH₂CH₂OCH₂CH₂O}{OPr ⁱ }] (2). Further reactions of (2) with internally functionalized oximes in anhydrous benzene yield heteroleptic complexes of the type [VO{OCH₂CH₂OCH₂CH₂O}{ON=C(R)(Ar)}] (3–8) {where R=CH₃, Ar=C₄H₃O-2 (3), C₄H₃S-2 (4), C₅H₄N-2 (5); and when R=H, Ar=C₄H₃O-2 (6), C₄H₃S-2 (7), C₅H₄N-2 (8)}. All these derivatives have been characterized by elemental analyses, molecular weight measurements and spectroscopic techniques. The crysoscopic molecular weight measurement as well as FAB mass study suggests dimeric nature of (2). However, FAB mass spectrum of (4), and the crysoscopic molecular weight measurements of (3), (4), (5) and (6) indicate the monomeric behavior of the oximato derivatives (3–8). Hexa-coordination around vanadium(V) has been proposed for both monomeric and dimeric derivatives. Sol–gel transformations of (1), (2) or (4) to vanadia [(a), (b) or (c), respectively] have been carried out at low sintering temperature (600 °C). The XRD patterns of (a), (b) or (c) indicate formation of a single orthorhombic phase in all the three cases. The SEM images suggest grain like [for (a) and (b)] and rod like [for (c)] morphology of the crystallites. IR, Raman spectra as well as EDX analyses indicate formation of pure vanadia. Absorption spectra of the vanadia (b) and (c) suggest energy band gaps of 2.53 and 2.65 eV, respectively.     

Synthesis, spectroscopic characterization and structure-activity relationship of some phosphoramidothioate pesticides

In this work, some phosphoramidothioates (PATs) with the general formula of (CH₃O)₂P(S)X and (CH₃O)(CH₃S)P(O)X, where, X = NH₂ (1 & 6), NH(CH₃) (2 & 7), N(CH₃)₂ (3 & 8), N(Et)₂ (4 & 9), (CH₃CH₂O)₂P(S)NH(CH₃) (5) and (CH₃CH₂O)(CH₃CH₂S)P(O)NH(CH₃) (10), were synthesized and characterized by ³¹P, ³¹P{¹H}, ¹³C and ¹H NMR spectroscopy. The ability of the compounds to inhibit AChE was predicted by PASS software (version 1.193). They were also experimentally evaluated by a modified Ellman??s assay. The structure-activity relationship (SAR) between IC50 and some physico-chemical properties such as lipophilicity (logP), electronic and steric effects of the compounds was studied. The logP values were experimentally determined by the shake-flask (gas chromatography) method. Inhibitory potency for the compounds 1?C10 was 1 (3.38 mM) > 2 (3.97 mM) > 3 (4.75 mM) > 4 (6.00 mM) > 5 (5.51 mM) > 6 (0.07 mM) > 7 (0.23 mM) > 8 (0.39 mM) > and 9 (0.55 mM) > 10 (0.51 mM), respectively. IC₅₀ and logP parameters of the P=O moiety were more than the P=S moiety in PAT analogues.     

Dinuclear nickel(II) complexes with Schiff base ligands: syntheses, structures and bio-relevant catalytic activities

Three Ni(II) complexes of cresol-based Schiff-base ligands, namely [Ni₂(L¹)(NCS)₃(H₂O)₂], (1) [Ni₂(L²)(CH₃COO)(NCS)₂(H₂O)] (2) and [Ni₂(L³)(NCS)₃] (3), (where L¹ = 2,6-bis(N-ethylpyrrolidineiminomethyl)-4-methylphenolato, L² = 2,6-bis(N-ethylpiperidineiminomethyl)-4-methylphenolato and L³ = 2,6-bis{N-ethyl-N-(3-hydroxypropyl iminomethyl)}-4-methylphenolato), have been synthesized and structurally characterized by X-ray single-crystal diffraction in addition to routine physicochemical techniques. Density functional theory calculations have been performed to understand the nature of the electronic spectra of the complexes. Complexes 1?C3 when reacted with 4-nitrophenyl phosphate in 50:50 acetonitrile?Cwater medium promote the cleavage of the O?CP bond to form p-nitrophenol and smoothly convert 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ) either in MeOH or in MeCN medium. Phosphatase- and catecholase-like activities were monitored by UV?Cvis spectrophotometry and the Michaelis?CMenten equation was applied to rationalize all the kinetic parameters. Upon treatment with urea, complexes 1 and 2 give rise to [Ni₂(L¹)(NCS)₂(NCO)(H₂O)₂] (1??) and [Ni₂(L²)(CH₃COO)(NCO)(NCS)(H₂O)] (2??) derivatives, respectively, whereas 3 remains unaltered under same reaction conditions.     

Diaquabromo(18-crown-6)rubidium and triaqua(18-crown-6)barium dibromide monohydrate: Synthesis and crystal structures

Two complexes are synthesized: diaquabromo(18-crown-6)rubidium [RbBr(18-crown-6)(H₂O)₂] (I) and triaqua(18-crown-6)barium dibromide monohydrate [Ba(18-crown-6)(H₂O)₃]²⁺ 2Br^? · H₂O (II). The orthorhombic structure of compound I (space group Pnma, a = 10.124 Å, b = 15.205 Å, c = 12.544 Å, Z = 4) and the monoclinic structure of compound II (space group C 2/c, a = 17.910 Å, b = 10.315 Å, c = 14.879 Å, β = 123.23°, Z = 4) are determined by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.063 (I) and 0.042 (II) for all 2293 (I) and 3363 (II) independent measured reflections (CAD-4 automated diffractometer, λMoK _α). The complex molecule [RbBr(18-crown-6)(H₂O)₂] in compound I and the randomly disordered cation [Ba(18-crown-6)(H₂O)₃]²⁺ in compound II are of the host-guest type: their Rb⁺ or Ba²⁺ cation (its coordination number is nine) is located in the cavity of the 18-crown-6 ligand and coordinated by all six O atoms. In structure I, the coordination polyhedron of Rb⁺ is a distorted hexagonal pyramid with a triple apex at the Br^? ligand and two O atoms of the water molecules. In structure II, the Ba²⁺ polyhedron is a distorted hexagonal bipyramid with one apex at the O atom of the water molecule and the other split apex at two O atoms of water molecules.     

Trichloro- and methyldichlorogermyl monochelates and dibromo- and dichlorogermyl bischelates derived from N,N-disubstituted amides of 2-hydroxycarboxylic acids

The reactions of GeCl₄, GeBr₄, and MeGeCl₃ with O-trimethylsilyl derivatives of N,N-disubstituted amides of 2-hydroxycarboxylic acids afforded pentacoordinate and hexacoordinate neutral (O,O)-mono- and (O,O)-bischelates. The reactions of glycolic acid derivatives with GeX₄ produced bischelates X₂Ge[OCH₂C(O)NR²R³]₂ 7a,c,d (X = Cl, R² = R³ = Me (a), (CH₂)₅ (c), (CH₂CH₂)₂O (d)) and 8a (X = Br). By contrast, the reactions of lactic and mandelic acid derivatives with GeCl₄ and MeGeCl₃ gave monochelates Cl₃Ge[OCH(R¹)C(O)NR²R³] (S)-9a–c (R¹ = Me) and Cl₂MeGe[OCH(R¹)C(O)NR²R³] 10a (R¹ = H), (S)-11a,b (R¹ = Me), and (S)-12a (R¹ = Ph) (R²R³ = (CH₂)₄ (b)), respectively. According to the X-ray diffraction data, the Ge atom in bischelates 7c,d and 8a has a coordination number 6, and its coordination polyhedron can be described as a slightly distorted octahedron. In monochelates (S)-9a-c, 10a, (S)-11a,b, and (S)-12a, the Ge atom has a coordination number 5, and its coordination polyhedron can be described as a trigonal bipyramid with two halogen atoms or one halogen atom and one ethereal oxygen atom in equatorial positions and the halogen atom and the amide oxygen atom in the axial positions. The bonds in the axial positions are somewhat longer than the corresponding bonds in tetracoordinate Ge compounds.     

Synthesis and molecular and crystal structures of binuclear complexes of Sm(III), Eu(III), Gd(III), Tb(III), and Dy(III) nitrates with 4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecane-2,8-dione

Binuclear complexes of Sm(III), Eu(III), Gd(III), Tb(III), and Dy(III) nitrates with 4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecane-2,8-dione (C₁₁H₂₀N₄O₂, SC)—[Sm(NO₃)₃(SC)(H₂O)]₂(I), [Eu(NO₃)₃(SC)(H₂O)]₂ (II), [Gd(NO₃)₂(SC)(H₂O)₃)]₂(NO₃)₂ (III), [Tb(NO₃)₃(SC)(H₂O)]₂ (IV), [Dy(NO₃)₃(SC)(H₂O)]₂ (V), are synthesized, and their X-ray diffraction analyses are carried out. The crystals of complexes I–V are monoclinic: space group P2₁/n for III and P2₁/c for I, II, IV, and V. In centrosymmetric coordination complexes II, III, IV, and V, the Ln atoms are coordinated by two O(1) and O(2) atoms of two molecules of the SC ligands bound by a symmetry procedure (1 ? x, ?y, 1 ? z), three bidentate nitrate anions, and a water molecule. The coordination numbers of the metal atoms are equal to 9, and the coordination polyhedra are considerably distorted three-capped trigonal prisms, whose bases include the O(1), O(2), O(12) and O(3), O(7), O(9) atoms. The dihedral angle between the bases of the prism is 18°, and that between the mean planes of the side faces is 55°–71° for I, 17° and 55°–71° for II, 16° and 55°–70° for IV, and 16° and 55°–70° for V. The Sm...Sm distance in complex I is 9.44 Å, Eu...Eu in II is 9.42 Å, Tb...Tb in IV is 9.36Å, and Dy...Dy in V is 9.36Å. The gadolinium atom in complex III is coordinated by two oxygen atoms of two ligand molecules bound by a symmetry procedure (?x, ?y + 1, ?z + 1), two bidentate nitrate anions, and three water molecules. One of the nitro groups in compound III is localized in the external coordination sphere of the metal. The coordination number of gadolinium is 9, and the coordination polyhedron is a significantly distorted three-capped trigonal prism, whose base includes the O(1), O(2), O(7) and O(4), O(5), O(9) atoms. The dihedral angle between the bases of the prism is 22.8°, and that between the mean planes of the side faces is 53°–72°. The Gd...Gd distance in complex III is 9.17 Å.     

New N-nicotinyl and N-isonicotinyl, N′,N″-diaryl phosphorictriamides with new Er(III) complex: synthesis, spectroscopic study and crystal structures

Ten new N-nicotinyl and N-isonicotinyl phosphoramidates with formula XP(O)R₂, X?=?Nicotinamide(nia), R?=?NHCH₂Ph (1), N(CH₃)CH₂Ph (2), NHCH(CH₃)Ph (3), NH-CH₂C₄H₃O (4), NHCH₂(C₅H₄N) (5), 3-NH-C₅H₄N (6), and YP(O)R₂, Y?=?isonicotinamide(iso), R?=?NHCH₂Ph (7), N(CH₃)CH₂Ph (8), NHCH(CH₃)Ph (9), NH-CH₂C₄H₃O (10) plus one new Er(III) complex with formula Er(L)₂(NO₃)₃ (11), L?=?(iso)PO(NHCH₂C₄H₃O)₂ (10), were synthesized and characterized by elemental analysis and ¹H, ¹³C, ³¹P NMR, IR, UV?Cvis spectroscopy. Crystal structures of compounds 10 and 11 were also determined by X-ray crystallography. Interestingly, the ¹H NMR spectra of compounds 1, 2, 6, 7, 9 indicated long-range ⁿ J _P,H (n?=?5,6,7) coupling constants, in the range of 1.4?C1.9?Hz, for the splitting of pyridine ring protons with phosphorus atom. IR results showed that the ??(C=O) values of compounds 7?C10 are greater than those of compounds 1?C5 which means that isonicotinyl moiety is more electron withdrawing than nicotinyl group. X-ray outcomes revealed that in complex 11 three phosphoric triamide ligands have been connected to each Er(III); one from N_pyridine and two from P=O donor sites. One of the P=O donor ligands is mono dentate while the other one acts as a bidentate ligand and coordinates to another Er atom via its N_pyridine site. By forming complex 11 the P=O and C?CN_amide bond lengths of ligand is increased in both, mono and bi dentate, ligands while the C=O bond length is decreased to lower values. These variations are in good agreement with IR results. All H-bonds and electrostatic interactions lead to form a three-dimensional polymeric cluster in the crystal lattice of 10 and 11.     

Synthesis and structure of new copper(II) coordination compounds with 8-quinoline aldehyde semicarbazones and thiosemicarbazones

Copper(II) salts were reacted with various quinoline aldehyde chalcogensemicarbazones to yield compounds formulated as Cu(HL)X₂ · nH₂O (I: HL = quinoline aldehyde thiosemicarbazone (HL¹), X = ClO₄, n = 2; II: HL = quinoline aldehyde 4-C₂H₅-thiosemicarbazone (HL^1a), X = NO₃, n = 0; III: HL = quinoline aldehyde semicarbazone (HL²), X = ClO₄, n = 3 and IV: HL = quinoline aldehyde 4-Ph-semicarbazone (HL^2a), X = NO₃, n = 1). Regardless of the reagent ratio, the products were compounds having the metal: ligand ratio of 1: 1, where the organic ligand was coordinated tridentate in a molecular form. Single-crystal X-ray diffraction showed that, depending on the chalcogen atom in the organic ligand (S or O), the substituent in the 4th position (at the terminal nitrogen atom), and the specifics of the acido ligand, complexes I–IV had appreciably differing molecular structure organizations. The structures of I and III are formed by a 1D charged coordination polymer, ClO ₄ ^? anions, and water molecules and may be described by the formula [Cu(HL)(H₂O)(ClO₄)] _n (ClO₄) _n · nH₂O. Copper(II) coordination polyhedra in I and II are (4 + 2) and (4 + 1 + 1) tetragonal bipyramids, respectively. In II and IV, the structures are monomeric and can be described as [Cu(HL^1a)(NO₃)₂] with the metal coordination polyhedron shaped as a (4 + 1) tetragonal pyramid in II and as [Cu(HL^2a)(H₂O)(NO₃)](NO₃) with the metal coordination polyhedron shaped as a (3 + 2) trigonal bipyramid in IV. The structure of II is built of molecular complexes, each comprising, apart from ligand HL^1a, two monodentate coordinated NO ₃ ^? groups. The oxygen atom of one anion together with the NNS donor atom set of ligand HL^1a form the base, and the oxygen atom of the other anion is in the apex of the coordination polyhedron. In IV, the structure is ionic and built of NO ₃ ^? anions and [Cu(HL^2a)(H₂O)(NO₃)]⁺ complex cations, where a cationic coordination polyhedron has a trigonal-bipyramidal configuration with organic ligand HL^2a positioned along the long edge. The bipyramidal base is made up by the oxygen atoms of the coordinated water molecule and monodentate nitrato group and the nitrogen atom N2 of the azomethyne group.     

Scorpionate nickel complexes with dicarboxylic acid ligands: influence of different spanning dicarboxylato co-ligands on the structures

Three new scorpionate nickel complexes [Tp*Ni(Hglu)(H₂O)]·EtOH (1), Tp*Ni(Haze)(MeOH) (2), and Tp*Ni(HTA)(H₂O) (3) (Tp*?=?hydrotris(3,5-dimethylpyrazolyl)borate) with different spanning dicarboxylo co-ligands (H₂glu?=?glutaric acid, H₂aze?=?azelaic acid, H₂TA?=?tetradecane diacid) were synthesized by solution methods at room temperature. X-ray crystallographic analyses of complexes 1?C3 demonstrate that these three octahedral Ni scorpionate complexes each contain an anionic chelating dicarboxylic acid, O₂C(CH₂) _n COOH, n?=?3, 7, and 12, respectively. The sixth coordination site is occupied by an ethanol, methanol, or water that is hydrogen bonded to the terminal carboxylic acid end of the anionic dicarboxylic acid ligand from a different Tp*Ni complex in the crystal lattice. Through these abundant hydrogen bond interactions, complexes 1 and 2 form 2D hydrogen bonding network structures, respectively, while complex 3 has a 1D infinite double-chain structure. The results of quantum mechanical calculations and thermogravimetric analyses on these complexes are presented and discussed.     

Ring-opening Copolymerization of Cyclohexene Oxide and Maleic Anhydride Catalyzed by Mononuclear [Zn（L）（H2O）] or Binuclear [Zn2（L）（OAc）2（H2O）] Complex Based on the Salen-type Schiff-base Ligand

From the self-assembly of the typical Salen-type Schiff-base ligand H2L and Zn(OAc)2·2H2O in the molar ratio of 1:1 or 1:2, the mononuclear [Zn(L)(H2O)](1) or binuclear [Zn2(L)(OAc)2(H2O)](2) are obtained, respectively. For both complexes 1 and 2, the unsaturated five-coordinate coordination environment to the catalytic active centers(Zn2+ ions) permits the monomer insertion for the effective solution copolymerization of cyclohexene oxide and maleic anhydride. All the solution copolymerizations afford poly(ester-co-ether)s, while lower catalyst and co-catalyst concentrations are helpful for the formation of alternating polyester. Of the three co-catalysts, 4-(dimethylamino)pyridine is found to be the most efficient, while an excess thereof is detrimental for chain growth of the copolymers.     

Two new 2D copper(II) complexes constructed from a flexible bis-pyridyl-bis-amide ligand and two aromatic tricarboxylates: syntheses, crystal structures, fluorescence, and electrochemical properties

Two new 2D metal-organic complexes, namely [Cu(3-dpyb)(1,2,4-HBTC)(H₂O)]·H₂O (1) and [Cu₃(3-dpyb)₃(SIP)₂(H₂O)₈]·6H₂O (2) [3-dpyb?=?N,N??-bis(3-pyridinecarboxamide)-1,4-butane, 1,2,4-H₃BTC?=?1,2,4-benzenetricarboxylic acid, H₃SIP?=?5-sulfoisophthalic acid], have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction analyses. Single crystal X-ray analyses reveal that the two Cu(II) complexes show different 2D coordination networks, the 4-connected (4⁴·6²) topology for complex 1 and the (4·6²)₂(4²·6²·8²) topology for complex 2. In the 2D layers of complexes 1 and 2, the 3-dpyb ligands adopt a typical ?? ₂-bridging mode (via ligation of two pyridyl nitrogen atoms), while 1,2,4-HBTC and SIP serve as a linear spacer and a ??V??-like linker, respectively, to connect the adjacent Cu(II) centers. The adjacent 2D layers are extended to 3D supramolecular networks via hydrogen-bonding interactions. The fluorescence properties of both complexes and electrochemical properties of complex 2 have also been investigated. The complex 2 bulk-modified carbon paste electrode (2-CPE) displayed a one-electron redox wave in potential range of 600?C200?mV in 1?M H₂SO₄ aqueous solution, and 2-CPE showed good electrocatalytic activity toward the reduction of nitrite.     

Synthesis,characterization,structures and magnetic property of chiral oxalate-bridged dicopper(Ⅱ) complexes

The oxalato-bridged dicopper(II) complexes [Cu2(μ-ox)(LRR)2(H2O)2(ClO4)2] (1),[Cu2(μ-ox)(LRR)2(CH3COCH3)2(ClO4)2](1a),[Cu2(μ-ox)(LSS)2(H2O)2(ClO4)2] (2) and [Cu2(μ-ox)(LRR)(LSS)2(CH3COCH3)2(ClO4)2] (3) [LRR = (8R,10R)-(-)-[4,5]-pineno2,2′-bipyridine,LSS = (8S,10S)-(+)-[4,5]-pineno-2,2′-bipyridine;ox2= oxalate] were first prepared.A possible mechanism for the formation of the chial dicopper(II) complexes was proposed.Based on elemental analysis,conductance measurement,UV-Vis spectra,CD spectra and X-ray single-crystal diffraction,the oxalato-bridged structures of 1 and 2 were deduced to adopt two Cu(II) ions and the bridged oxalate lying in the nearly same plane.The crystal structures of 1a and 3 reveal that the coordination geometry around each Cu(II) ion is an elongated and distorted octahedron and two axial solvent molecules and two perchlorate ions are anti to each other respectively in both binuclear molecules.The solution CD spectra of 1 and 2 in the visible d-d range show very weak Cotton effects with peaks at 588 and 779 nm,which are approximately of mirror image,suggesting the optical activities may be derived from the vicinal effects of the chiragenic centers at the pinene group of LRR and LSS,respectively.Complex 1 has been characterized by variable-temperature magnetic susceptibility and the data was least-square fitted to the Blenaey-Bowers equation.The exchange integral J was found to be -338.41(4) cm-1,indicating a strong antiferromagnetic interaction between two copper(II) ions.     

Amidoamine-based dendrimers with end-grafted Pd-Fe units: Synthesis, characterization and their use in the Heck reaction

The synthesis and characterization of novel amidoamine-based metallodendrimers with heterobimetallic end-grafted amidoferrocenyl-palladium-allyl chloride units is described. Dendrimer (Fe((η⁵-C₅H₄PPh₂)(η⁵-C₅H₄))C(O)HNCH₂CH₂NHC(O)CH₂CH₂)N[CH₂CH₂N(CH₂CH₂C(O)NHCH₂CH₂NH-C(O)(Fe(η⁵-C₅H₄)(η⁵-C₅H₄PPh₂)))₂]₂ (9-Fe) and the corresponding metal species (Fe((η⁵-C₅H₄PPh₂(Pd(η³-C₃H₅)Cl))(η⁵-C₅H₄))C(O)HNCH₂CH₂NHC(O)CH₂CH₂)N[CH₂CH₂N(CH₂CH₂C(O)NHCH₂CH₂NHC(O)(Fe(η⁵-C₅H₄)(η⁵-C₅H₄PPh₂(Pd(η³-C₃H₅)Cl))))₂]₂ (9-Fe-Pd) were prepared by a consecutive divergent synthesis methodology including addition-amidation cycles, standard peptide coupling, and coordination procedures. For comparative reasons also the monomeric and dimeric molecules (Fe(η⁵-C₅H₄PPh₂)(η⁵-C₅H₄C(O)NHⁿC₃H₇)) (5-Fe) and [Fe(η⁵-C₅H₄PPh₂)(η⁵-C₅H₄C(O)NHCH₂)]₂ (6-Fe) as well as N(CH₂CH₂C(O)NHCH₂CH₂NHC(O)(Fe(η⁵-C₅H₄)(η⁵-C₅H₄PPh₂)))₃ (7-Fe) and [CH₂N(CH₂CH₂C(O)NHCH₂CH₂NHC(O)(Fe(η⁵-C₅H₄)(η⁵-C₅H₄PPh₂)))₂]₂ (8-Fe) were prepared from Fe(η⁵-C₅H₄PPh₂)(η⁵-C₅H₄CO₂H) (3). Using [Pd(η³-C₃H₅)Cl]₂ (4) as palladium source heterobimetallic metallodendrimers (Fe(η⁵-C₅H₄PPh₂(Pd(η³-C₃H₅)Cl))(η⁵-C₅H₄C(O)NHⁿC₃H₇)) (5-Fe-Pd), [Fe(η⁵-C₅H₄PPh₂(Pd(η³-C₃H₅)Cl))(η⁵-C₅H₄C(O)NHCH₂)]₂ (6-Fe-Pd), N(CH₂CH₂C(O)NHCH₂CH₂NHC(O)(Fe(η⁵-C₅H₄)(η⁵-C₅H₄PPh₂(Pd(η³-C₃H₅)Cl))))₃ (7-Fe-Pd) and [CH₂N(CH₂CH₂C(O)NHCH₂CH₂NHC(O)(Fe(η⁵-C₅H₄)(η⁵-C₅H₄PPh₂(Pd(η³-C₃H₅)Cl))))₂]₂ (8-Fe-Pd) were synthesized. Additionally, seleno-phosphines of 5-Fe-Se and 9-Fe-Se, respectively, were prepared by addition of elemental selenium to 5-Fe or 9-Fe to estimate their σ-donor properties.The palladium-containing amidoamine supports are catalytically active in the Heck-Mizoroki cross-coupling of iodobenzene with tert-butyl acrylate. The catalytic data are compared to those obtained for the appropriate mononuclear and dinuclear compounds 5-Fe-Pd and 6-Fe-Pd. This comparison confirms a positive cooperative effect. The mercury drop test showed that (nano)particles were formed during catalysis, following on heterogeneous carbon-carbon cross-coupling.     

Structural diversity of transition-metal coordination polymers derived from isophthalic acid and bent bis(imidazole) ligands

Four coordination polymers associated with bent bis(imidazole) 1,3-bis(imidazol-l-yl-methyl)benzene (mbix) and isophthalic acid (H₂ip) or 5-methylisophthalic acid (H₂mip) ligands, formulated as {[Cd(mbix)(mip)]·H₂O} _n (1), {[Co(mbix)(mip)]·0.4H₂O} _n (2) [Ni(mbix)(mip)H₂O] _n (3) and [Ni(mbix)(ip)] _n (4), were synthesized under hydrothermal conditions and characterized by physico-chemical and spectroscopic methods. Complexes 1 and 2 are isomorphous and exhibit a 1D loop-like chain. Complex 3 features a 2D (4,4) layer, which further extends into an unusual 2D (3,5)-connected 3,5L2 double-layered supramolecular network via classical O–H···O hydrogen bonding interactions. Complex 4 is a 3D network, which shows a rare binodal (3,5)-connected 3,5T1 framework. Moreover, the luminescence and catalytic properties of the complexes for the degradation of methyl orange by sodium persulfate in a Fenton-like process are reported.     

8-Dioxane ferra(III) bis(dicarbollide): A paramagnetic functional molecule as versatile building block for introduction of a Fe(III) centre into organic molecules

The synthesis of a new, paramagnetic closo-[(8-(-CH₂CH₂O)₂-1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)-3,3′-Fe]⁰ (3) is reported. This compound can serve as a versatile building block for construction of both anionic and zwitterionic derivatives, as exemplified by the synthesis of a series of compounds of general formula closo-[(8-X-(CH₂CH₂O)₂-1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)-3,3′-Fe], bearing organic end groups (X = NC₅H₅ (4), (C₆H₅)₃P (5), OH (6), and 2-O(1-CH₃O-C₆H₄) (7)) attached to the cluster by a diethyleneglycol spacer. Molecular structures of 3, 4, 5 and 7 were determined by single-crystal X-ray diffraction analysis and by the long-time neglected method of paramagnetic, high field NMR (¹H, ¹³C and ¹¹B) spectroscopy.     

Cobalt(II) and silver(I) coordination polymers constructed from flexible bis(5,6-dimethylbenzimidazole) and substituted isophthalate co-ligands

Two coordination polymers, [Co(L1)(IPA] _n (1) and {[Ag(L2)(HMIPA)]·H₂O} _n (2) (H₂IPA = isophthalic acid, L1 = 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H₂MIPA = 5-methylisophthalic acid, L2 = 1,6-bis(5,6-dimethylbenzimidazol-1-yl)hexane, have been synthesized and characterized by physicochemical and spectroscopic methods, as well as single-crystal X-ray diffraction. In 1, six-coordinated cobalt centers are bridged by L1 and IPA^2? ligands to generate a (4,4) two-dimensional layer. However, complex 2 features a 1D chain structure, which is further extended by O–H···O hydrogen bonding interactions into a 2D supramolecular layer with (6³) topology. The fluorescence and thermal gravimetric analysis of both complexes were also explored. Furthermore, the complexes 1 and 2 exhibit remarkable catalytic properties for the degradation of methyl orange dyes in a Fenton-like process.     

Ammonium and potassium citratogermanates(IV): Synthesis, chemical compositions, and structures. The crystal structures of (NH4)[Ge(OH)(H2Cit)2] · H2O and K4[Ge(HCit)2(H2Cit)] · 3H2O

Methods for the synthesis of ammonium citratogermanate (NH₄)[Ge(OH)(H₂Cit)₂] · H₂O (I) and potassium citratogermanate (K₄[Ge(HCit)₂(H₂Cit)] · 3H₂O (II), where H₄Cit is citric acid) in aqueous MeCN were developed. The individuality, chemical composition, and thermal stability of complexes I and II were proved by elemental analysis, thermogravimetry, and IR spectroscopy. According to X-ray diffraction data, the coordination numbers of the Ge atoms are 5 and 6 and their coordination polyhedra are a square pyramid and an octahedron in complexes I and II, respectively. In both complexes, the Ge atom coordinates the deprotonated OH group and the α-carboxyl group of the ligands H _n Cit^4?n to form five-membered chelate rings. Hydrogen bonds in I as well as potassium cations in II serve to unite these complexes into frameworks.     

Copper complexes of two isomeric NS2-macrocycles

Two isomeric NS₂-macrocycles incorporating a xylyl group at ortho (o -L) and meta (m -L) positions were employed and their copper complexes (1?C5) were prepared and structurally characterized. The copper(II) nitrate complexes [Cu(L)(NO₃)₂] (1: L = o -L, 2: L = m -L) for both ligands were isolated. In each case, the copper center is five-coordinated with a distorted square pyramidal geometry. Despite the overall geometrical similarity, 1 and 2 show the different ligand conformation due to the discriminated packing pattern. Reaction of o -L with copper(II) perchlorate afforded complex 3 containing two independent complex cations [Cu(o -L)(H₂O)(DMF)(ClO₄)]⁺ and [Cu(o -L)(H₂O)(DMF)]²⁺; the coordination geometry of the former is a distorted octahedron while the latter shows a distorted square pyramidal arrangement. In the reactions of copper(I) halides (I or Br), o -L gave a mononuclear complex [Cu(o-L)I] (4) with a distorted tetrahedral geometry, while m -L afforded a unique exodentate 2:1 (ligand-to-metal) complex [trans-Br₂Cu(m-L)₂] (5) adopting a trans-type square-planar arrangement.     

Polycarboxylate-assisted assembly of cobalt(II) metal–organic coordination polymers from a “V”-shaped tri-pyridyl-bis-amide ligand

The aim of this study was to explore the influence of the position and angles of carboxyl groups of polycarboxylates on constructing coordination polymers. Three Co(II) metal–organic coordination polymers based on a tri-pyridyl-bis-amide ligand, namely [Co(L)(1,2-BDC)(H₂O)₂]·2H₂O (1), [Co(L)(1,4-BDC)(H₂O)₂]·2H₂O (2) and [Co(L)₂(BTEC)_0.5]·H₂O (3) (L = N,N′-bis(pyridine-3-yl)pyridine-2,6-dicarboxamide, 1,2-H₂BDC = 1,2-benzenedicarboxylic acid, 1,4-H₂BDC = 1,4-benzenedicarboxylic acid, H₄BTEC = 1,2,4,5-benzenetetracarboxylic acid), have been obtained by tuning the auxiliary polycarboxylate ligands. Structural analyses reveal that complexes 1–3 display diverse structures. Complex 1 displays a meso-helical chain linked by L ligands, which is further extended into a three-dimensional supramolecular framework through hydrogen-bonding interactions. The 1,2-BDC with a chelating coordination mode only acts as the hydrogen bond acceptor. In complex 2, the 1,4-BDC anions connect adjacent Co(II) atoms to form a linear chain, which is connected by hydrogen-bonding interactions to construct a 3D supramolecular network. Complex 3 exhibits a chain, which is composed of left-/right-handed Co-L helical chains and Co-BTEC linear chain. The 1D chains are ultimately extended into a two-dimensional supramolecular network by hydrogen-bonding interactions. Moreover, the thermal stability and the fluorescent properties of the title complexes and the electrochemical behaviors of a bulk-modified carbon paste electrode with complex 2 have been investigated at room temperature.     

Structure of [Dy(Phen)(C4H8NCS2)3]·3CH2Cl2 solvate. Magnetic properties and photoluminiscence of [Ln(Phen)(C4H8NCS2)3] (Ln = Sm,Eu, Tb,Dy, Tm) complexes

It is found that diffraction patterns of complexes I–V of the composition [Ln(Phen)(C₄H₈NCS₂)₃] (Ln = Sm, Eu, Tb, Dy, and Tm respectively) are similar. Single crystals of [Dy(Phen)(C₄H₈NCS₂)₃]·3CH₂Cl₂ (VI) obtained are. According to the X-ray crystallographic data, in the structure of VI the unit cell contains two crystallographically independent molecules of the [Dy(Phen)(C₄H₈NCS₂)₃] complex and six CH₂Cl₂ molecules. The N₂S₆ coordination polyhedron of the Dy atom is a distorted square antiprism. In the range of 2–300 K the magnetic properties of complexes I–V are studied. It is found that complex III passes to the magnetically ordered state; the spontaneous magnetization at 2 K is 24 600 G·cm³/mol. At 300 K compounds I–IV exhibit photoluminescence in the visible spectral range. It is found that the photoluminescence intensity of complex I is several times higher than the photoluminescence intensity of complexes II–IV.