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The synthesis and characterization of covalent, metal-organic networks that are based on titanium-aryloxide bonds is discussed. Compared with most coordination polymers, creation of such networks cannot be attained through reversible dative bonding, but through the alcoholysis of a precursor titanium alkoxide. Dense 3-dimensional networks are produced when the solvent is a poor ligand partly because octahedral coordination is achieved by titanium.

Reaction of (N3N)ZrX complexes (X = amido, Cl−, CH3−) with carbodiimide substrates results in insertion into an Zr–N bond of the triamidoamine ligand rather than the Zr–X bond as has been observed for related (N3N)ZrX complexes (X = PR2−, AsR2−). [ABSTRACT FROM AUTHOR]

Tris[(2-indole)methyl]amine, N(CH[sub 2]inH)[sub 3], may be readily obtained by reaction of methyl 2-bromomethyt-1-indolecarboxylate with NH[sub 3] followed by deprotection with NaOMe/MeOH. In its deprotohated form, [N(CH[sub 2]in[sub )]3][sup 3-] is an efficient tetradentate trianionic ligand for tantalum, as illustrated by the isolation and structural characterization of [η[sup 4]-N(CH[sub 2]in)[sub 3]]Ta(NAr)(NMe[sub 2]H) (Ar = 2,6C[sub 6]H[sub 3]Pr[sup i, sub 2]), [η[sup 4]-N(CH[sub 2]in)[sub 3]]Ta(NMe[sub 2])[sub 2] and [η[sub 4]-N(CH[sub 2]in)[sub 3]]Ta(NMe[sub 2])Ct. The [N(CH[sub 2]in)[sub 3]][sup 3-] ligand has a structural similarity to that of [N(CH[sub 2]CH[sub 2]NR)[sub 3]][sup 3-] , but differs electronically from the latter due to its reduced π-donor capability, a direct result of the nitrogen being a component of the aromatic π-system of the indolyl fragment. [ABSTRACT FROM AUTHOR]

Examines the reaction of a molybdenum (Mo) compound with six-membered heterocyclic nitrogen compounds. Molecular structure of Mo compounds; Binding of the indolyl ligand to the six-membered arene ring; Coordination through the six-membered ring.

A series of rhenium tricarbonyl complexes coordinated by asymmetric diimine ligands containing a pyridine moiety bound to an oxazoline ring were synthesized, structurally and electrochemically characterized, and screened for CO 2 reduction ability. The reported complexes are of the type Re(N-N)(CO) 3 Cl, with N-N = 2-(pyridin-2-yl)-4,5-dihydrooxazole (1), 5-methyl-2-(pyridin-2-yl)-4,5-dihydrooxazole (2), and 5-phenyl-2-(pyridin-2-yl)-4,5-dihydrooxazole (3). The electrocatalytic reduction of CO 2 by these complexes was observed in a variety of solvents and proceeds more quickly in acetonitrile than in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The analysis of the catalytic cycle for electrochemical CO 2 reduction by 1 in acetonitrile using density functional theory (DFT) supports the C-O bond cleavage step being the rate-determining step (RDS) (ΔG ⧧ = 27.2 kcal mol -1 ). The dependency of the turnover frequencies (TOFs) on the donor number (DN) of the solvent also supports that C-O bond cleavage is the rate-determining step. Moreover, the calculations using explicit solvent molecules indicate that the solvent dependence likely arises from a protonation-first mechanism. Unlike other complexes derived from fac-Re(bpy)(CO) 3 Cl (I; bpy = 2,2'-bipyridine), in which one of the pyridyl moieties in the bpy ligand is replaced by another imine, no catalytic enhancement occurs during the first reduction potential. Remarkably, catalysts 1 and 2 display relative turnover frequencies, (i cat /i p ) 2 , up to 7 times larger than that of I.

The title compound [systematic name: (R)-(-)-2-acet-oxy-2-phenyl-acetic acid], C10H10O4, is a resolved chiral ester derivative of mandelic acid. The compound contains an acetate group and a carb-oxy-lic acid group, which engage in inter-molecular hydrogen bonding, forming chains extending parallel to [001] with a short donor-acceptor hydrogen-bonding distance of 2.676 (2) Å.

The synthesis and characterization of two copper(II) complexes containing 2-(2-pyridyl)benzimidazole (PyBIm) are reported with the biological activity of these two complexes and a third Cu(II) complex containing 2-(2-pyridyl)benzothiazole (PyBTh). Complex 1, [Cu(PyBIm)(NO3)(H2O)](NO3), is a four coordinate, distorted square planar species with one ligand (N,N), nitrate and water bound to Cu(II). The [Cu(PyBIm)3](BF4)2 complex (2) has distorted octahedral geometry with a 3:1 Py(BIm) ligand to metal ratio. The distorted trigonal bi-pyramidal geometry of compound 3, [Cu(PyBTh)2(H2O)](BF4)2, is comprised of two PyBTh ligands and one water. Biological activity of 1-3 has been assessed by analyzing DNA interaction, nuclease ability, cytotoxic activity and antibacterial properties. Complex 3 exhibits potent concentration dependent SC-DNA cleavage forming single- and double-nicked DNA in contrast to the weak activity of complexes 1 and 2. Mechanistic studies indicate that all complexes utilize an oxidative mechanism however 1 and 2 employ O2(-) as the principal reactive oxygen species while the highly active 3 utilizes (1)O2. The interaction between 1-3 and DNA was investigated using fluorescence emission spectroscopy and revealed all complexes strongly intercalate DNA with Kapp values of 2.65 × 10(6), 1.85 × 10(6) and 2.72 × 10(6)M(-1), respectively. Cytotoxic effects of 1-3 were examined using HeLa and K562 cells and show cell death in the micromolar range with the activity of 1 ≈ 2 and were slightly higher than 3. Similar reactivity was observed in the antibacterial studies with E. coli and S. aureus. A detailed comparative analysis of the three complexes is presented., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The two title compounds are isomers of C6H3ClN2 containing a pyridine ring, a nitrile group, and a chloro substituent. The mol-ecules of each compound pack together in the solid state with offset face-to-face π-stacking, and inter-molecular C-H⋯Nnitrile and C-H⋯Npyridine inter-actions. 4-Chloro-pyridine-2-carbo-nitrile, (I), exhibits pairwise centrosymmetric head-to-head C-H⋯Nnitrile and C-H⋯Npyridine inter-actions, forming one-dimensional chains, which are π-stacked in an offset face-to-face fashion. The inter-molecular packing of the isomeric 6-chloro-pyridine-2-carbo-nitrile, (II), which differs only in the position of the chloro substituent on the pyridine ring, exhibits head-to-tail C-H⋯Nnitrile and C-H⋯Npyridine inter-actions, forming two-dimensional sheets which are π-stacked in an offset face-to-face fashion. In contrast to (I), the offset face-to-face π-stacking in (II) is formed between mol-ecules with alternating orientations of the chloro and nitrile substituents.

The reaction of Na[RuCl4(SO(CH3)2)2], 1, with one equivalent of FcCONHCH2C6H4N (Fc=FeC10H9), L1, FcCOOCH2CH2C3H3N2, L2, FcCOOC6H4N, L3, afforded the dinuclear species, Na[FcCONHCH2C6H4N[RuCl4(SO(CH3)2)]], RuL1, Na[FcCOOCH2CH2C3H3N2[RuCl4(SO(CH3)2)]], RuL2, Na[FcCOOC6H4N(RuCl4(SO(CH3)2))], RuL3, respectively, yielding, in each case, a ferrocene moiety bridged to a ruthenium center. The complexes were characterized by NMR, IR, and XRD (X-ray diffraction). The sulfoxide ligands are bonded to the metal through the sulfur atom. The complexes were evaluated for their biological activity with pBluescript DNA plasmid, and the protein BSA (bovine serum albumin). These reactions were monitored by XAS (X-ray absorption spectroscopy), EXAFS (extended X-ray Absorption Fine Structure), NMR, UV/visible, emission spectroscopy, and gel electrophoresis. Donor atoms from the biomolecules substitute for the chloride ligands in the parent complexes., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A series of Cu(II) complexes with ligand frames based on quinoline derivatives appended with a benzothiazole substituent has been isolated. The complexes, Cu(Q(oBt))(NO3)2(H2O)∙CH3OH (1∙CH3OH), Cu(8OHQ(oBt))Cl2∙CH3OH (2∙CH3OH), Cu(8OQ(oBt))Cl(CH3OH)∙CH3OH (3∙CH3OH) and [Cu(8OH1/2Q(oBt))(CH3OH)(NO3)]2(NO3) (4) have been characterized by single crystal X-ray diffraction, IR and UV-visible spectroscopies, and elemental analysis. The ligand frame within the set of complexes differs in the substituent on the quinoline ring: complex 1 remains unsubstituted at this position while complexes 2-4 have a substituted OH group. In complex 2, the bound phenol remains protonated while in 3 it is a phenolato group. Complex 4 contains two complexes within the unit cell and one NO3(-) giving rise to an overall 'half-protonation'. The interaction between complexes 1-3 with CT-DNA was investigated using fluorescence emission spectroscopy and revealed 2 and 3 strongly intercalate DNA with Kapp values of 1.47×10(7)M(-1) and 3.09×10(7)M(-1), respectively. The ability of complexes 1-3 to cleave SC-DNA was monitored using gel electrophoresis. Each complex exhibits potent, concentration dependent nuclease activity forming single and double-nicked DNA as low as 10μM. The nuclease activity of complexes 1-3 is primarily dependent on (1)O2 species while ·OH radicals play a secondary role in the cleavage by complexes 2 and 3. The cytotoxic effects of 1-3 were examined using HeLa cells and show cell death in the micromolar range. The distribution of cell cycle stages remains unchanged when complexes are present indicating DNA damage may be occurring throughout the cell cycle., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The title compound, C9H7FO, crystallizes with two independent mol-ecules in the asymmetric unit, in which corresponding bond lengths are the same within experimental error. The five-membered ring in each molecule is almost planar, with r.m.s. deviations of 0.016 and 0.029 Å. In the crystal, mol-ecules form sheets parallel to (1 0 0) via C-H⋯O and C-H⋯F inter-actions with F⋯F contacts [3.1788 (16) and 3.2490 (16) Å] between the sheets.

The title compound, C15H15N, represents an E isomer. The mol-ecule exhibits a minor [9.1 (2)%] disorder with methyl-benzyl-idene and benzyl groups inter-changing their positions. The C=N bond length is 1.292 (2) Å. The mol-ecular geometry is essentially planar, with the maximal twist of 8.5 (3)° for the benzyl group. The herringbone packing arrangement does not exhibit any π-stacking inter-actions.

In the title four-coordinate complex, [Ti(C(2)H(6)N)(2)(C(31)H(28)O(4))], two symmetry-independent mol-ecules are present in the asymmetric unit. The Ti(IV) atom displays a distorted tetra-hedral geometry, with Ti-O bond lengths ranging from 1.805 (3) to 1.830 (3) Å and O-Ti-O ligand bite angles of 100.16 (12) and 101.36 (12)°. The short Ti-N bond distances, ranging from 1.877 (4) to 1.905 (4) Å, indicate strong bonding between the Ti(IV) atom and the dimethyl-amide ligands.

The title compound, [Au(C(18)H(27)ClN(3))(C(18)H(15)P)](NO(3))(2), is a coordination complex of gold(I) triphenyl-phosphine with the N atom in the quinoline ring of the common anti-malarial compound chloro-quine (CQ). The pendant diethyl-amino group of the CQ ligand was found to be protonated. The complex exhibits a nearly linear coordination geometry around the Au(I) atom [N-Au-P = 176.94 (6)°], with Au-N and Au-P bond lengths of 2.070 (2) and 2.2338 (7) Å, respectively. The diethylammonium group and one of the two nitrate counter-ions are disordered with occupancy ratios of 0.519 (4):0.481 (4). The nitrate anions are hydrogen bound to both the amino and ammonium groups of the N,N-diethylpentanaminium fragment of the CQ.

The title compound (HMF), C(6)H(6)O(3), is one of the products of acid-catalyzed dehydration of high-fructose corn syrup, and has been shown to be toxic to honey bees. The compound was crystallized at 276 K, and it was found that the two independent mol-ecules in the asymmetric unit form an infinite O-H⋯O hydrogen-bonding chain that is linked into a three-dimensional network structure by weak inter-molecular C-H⋯O contacts.

The title compound, [Al(CH(3))(2)(C(25)H(21)N(2)O)(C(4)H(8)O)], was isolated as a minor component from a reaction mixture of the parent indolyl ligand and trimethyl-aluminum in tetra-hydro-furan. The ligands adopt a distorted tetra-hedral geometry around aluminium. Obvious hydrogen-bonding interactions are not present.

The title compound, [Zn(CH(3))(2)(C(15)H(11)N(3))], was synthesized by the addition of dimethyl-zinc to 2,2':6',2''-terpyridine and was crystallized by the slow evaporation of THF. The penta-coordinate Zn(II) atom, lying on a twofold rotation axis, displays a distorted trigonal-bipyramidal geometry, with two terminal N atoms at the axial positions and the central N atom and two methyl C atoms at the equatorial positions.

The centrosymmetric title compound, [SnI(4)(C(21)H(21)OP)(2)], is a monomeric complex that displays a nearly octa-hedral coordination of tin(IV), with an Sn-O bond distance of 2.159 (2) Å and an average Sn-I bond distance of 2.79 (3) Å.

The title mononuclear complex, [Zr(C(20)H(20)Cl(4)N(2)O(2))(2)], was obtained by allowing hexane to diffuse into a diethyl ether solution of zirconium(IV) sec-butoxide and the enanti-o-meri-cally pure tetra-dentate ligand N,N'-bis-(3,5-dichloro-2-hy-droxy-benz-yl)-trans-(R,R)-1,2-diamino-cyclo-hexane. The metal centre is eight-coordinate and displays a distorted dodeca-hedral coordination environment with average Zr-O and Zr-N bond lengths of 2.082 (9) and 2.441 (8) Å, respectively. In the crystal structure, complex mol-ecules are linked by inter-molecular C-H⋯Cl hydrogen-bond inter-actions into zigzag chains running parallel to the [101] direction. C-H⋯O and N-H⋯O hydrogen bonds are also present.

The title compound, [SnI(4)(C(25)H(22)O(2)P(2))]·CHCl(3), crystallized from a chloro-form solution of SnI(4) and the diphosphine CH(2)(PPh(2))(2) exposed to air. The monomeric complex displays a distorted octa-hedral coordinaton for the tin(IV) atom with average Sn-I and Sn-O bond lengths of 2.79 (2) and 2.15 (1) Å, respectively.

The nickel boratrane complexes [kappa4-B(mimBut))3]Ni(kappa1-OAc), [kappa4-B(mimBut)3]NiNCS and [kappa4-B(mimBut)3]NiN3 are obtained via metathesis of the chloride ligand of [kappa4-B(mimBut)3]NiCl with TlOAc, KSCN and NaN3, respectively; the Ni-->B bond in these complexes is a site of reactivity, thereby providing a means of synthesizing nickel complexes that feature B-functionalized tris(mercaptoimidazolyl)borate derivatives, [YTmBut]NiZ.

The title compound, [Zr(CH(3))(C(15)H(39)N(4)Si(3))], is a unique example of a triamido-amine-supported zirconium-methyl complex that crystallized as a monomer with trigonal-bipyramidal geometry at zirconium, featuring a Zr-C bond of 2.2963 (16) Å.

A new type of mixed-metal trinuclear complex containing platinum(II) and ruthenium(III) fragments that resemble both cisplatin and NAMI-A has been synthesized and characterized by IR, 1H NMR, elemental analysis, and X-ray crystallography. The water-soluble compound Na2{trans,cis,trans-[RuIIICl4(DMSO-S)(mu-pyz)]2PtIICl2} (AH-197, pyz = pyrazine) was assessed for its effects on DNA mobility and toxicity against human cancer cell lines. When compared to cisplatin and KP-1019 (which structurally resembles NAMI-A), IC50 results showed that AH-197 had an intermediate toxicity. When this data was coupled with a subsequent COMPARE evaluation (standard COMPARE queries resulted in insignificant correlation coefficients (<0.70) while very low COMPARE correlation coefficients were found in the matrix queries as well), AH-197 yielded a correlation coefficient of 0.19 when compared to cisplatin and 0.25 when compared to KP1019 indicating that AH-197 has a unique behavior.

Triamidoamine-supported zirconium complexes catalyze the heterodehydrocoupling of primary phosphines with silane and germanes. In this catalysis, P-Si or P-Ge products are observed exclusively with no competitive P-P bond formation. Phosphido complexes (N3N)ZrPHR (N3N = N(CH2CH2NSiMe3)33-, R = Ph, 2; Cy, 3) were observed to be the catalyst resting state, and complex 2 was structurally characterized.

Single crystal rotational echo double resonance (REDOR) experiments can be used to determine the three-dimensional orientation of heteronuclear bond vectors in an amino acid, as well as the crystal's orientation relative to the rotor fixed frame (RFF). We also demonstrate that for samples uniaxially aligned along the rotor axis, the polar tilt angle of a bond vector relative to the RFF can be measured by use of an analytical expression that describes the REDOR curve for that system. These bond orientations were verified by X-ray indexing of the single crystal sample, and were shown to be as accurate as +/- 1 degrees .

Antimony compounds that feature multidentate aryloxide ligands, namely [eta4-N(o-C6H4O)3]Sb(OSMe2), {{[eta3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(mu2-O)}2, and {[eta3-PhN(o-C6H4O)2]Sb}4(mu3-O)2 have been synthesized from N(o-C6H4OH)3 and PhN(o-C6H4OH)2 and structurally characterized by X-ray diffraction. While [eta4-N(o-C6H4O)3]Sb(OSMe2) exists as a discrete mononuclear species, the oxo complexes {{[eta3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(mu2-O)}2 and {[eta3-PhN(o-C6H4O)2]Sb}4(micro3-O)2 are multinuclear. Specifically, the dinuclear fragment {[eta3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(mu2-O)} exists in a dimeric form due to the bridging oxo ligand participating in an intermolecular hydrogen bonding interaction, while the dinuclear fragment {[eta3-PhN(o-C6H4O)2]Sb}2(mu-O) exists in a dimeric form due to the bridging oxo ligand serving as a donor to the antimony of a second fragment. The structures of {{[eta3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(mu2-O)}2 and {[eta3-PhN(o-C6H4O)2]Sb}4(mu3-O)(2), therefore, indicate that an oxo ligand bridging two Sb(III) centers is sufficiently electron rich to serve as both an effective hydrogen bond acceptor and as a ligand for an additional Sb(III) center.

Antimony compounds are widely used as catalysts for the synthesis of the commercially important polymer poly(ethyleneterephthalate) by polycondensation of bis(hydroxyethyl)terephthalate. The precise nature of the antimony catalysts is, however, unknown. The present study has been conducted with a view to determining the nature of the catalytic species by structurally characterizing antimony ethylene glycolate compounds and related catecholate derivatives, namely [Sb(2)(OCH(2)CH(2)O)(3)](n), [Sb(OCH(2)CH(2)O)(OAc)](n), [pySb(1,2-O(2)C(6)H(4))](2)O, and [pyH][Sb(1,2-O(2)C(6)H(4))(2)].