Solid State and Solution Structures of Lanthanide Nitrate Complexes of Tris-(1-napthylphosphine oxide).

Coordination complexes of lanthanide metals with tris-1-naphthylphosphine oxide (Nap3PO, L) have not been previously reported in the literature. We describe here the formation of lanthanide(III) nitrate complexes Ln(NO3)3L4 (Ln = Eu to Lu) and the structures of [Ln(NO3)3L2]·2L (Ln = Eu, Dy, Ho, Er) and L. The core structure of the complexes is an eight-coordinate [Ln(NO3)3L2] with the third and fourth ligands H-bonded via their oxygen atoms to one of the naphthyl rings. The structures are compared with those of the analogous complexes of triphenylphosphine oxide and show that the Ln-O(P) bond in the Nap3PO complexes is slightly longer than expected on the basis of differences in coordination numbers. The reaction solutions, investigated by 31P and 13C NMR spectroscopy in CD3CN, show that coordination of L occurs across the lanthanide series, even though complexes can only be isolated from Eu onwards. Analysis of the 31P NMR paramagnetic shifts shows that there is a break in the solution structures with a difference between the lighter lanthanides (La-Eu) and heavier metals (Tb-Lu) which implies a minor difference in structures. The isolated complexes are very poorly soluble, but in CDCl3, NMR measurements show dissociation into [Ln(NO3)3L2] and 2L occurs.

Complexes of lanthanide nitrates with tri tert butylphosphine oxide.

Reaction of lanthanide nitrates with (t)Bu(3)PO (=L) lead to the isolation of complexes Ln(NO(3))(3)L(2)·H(2)O·nEtOH (Ln = La (1), Nd(2)), Ln(NO(3))(3)L(2) ·nEtOH (Sm(3), Eu(4)), and Ln(NO(3))(3)L(2) (Dy(5), Er(6), Lu(7)). These have been characterized by elemental analysis, infrared and NMR((1)H, (13)C and (31)P) spectroscopy and single-crystal X-ray diffraction. The structures show L to be positioned on opposite sides of the metal with the nitrates forming an equatorial band. When Ln = Dy, Er, and Lu two distinct molecules are present in the unit cell. A major isomer (70%) has a (P)O-Ln-O(P) angle of less than 180° with one of the nitrate ligands twisted out of the plane of the other nitrates while the lower abundance isomer is more symmetric with the (P)O-Ln-O(P) angle of 180° and the nitrate ligands coplanar giving a hexagonal bipyramidal geometry. These isomers cannot be observed by variable temperature solution (31)P NMR measurements but are clearly seen in the solid-state NMR spectrum of the Lu complex. Variable temperature solid-state NMR indicates that the isomers do not interconvert at temperatures up to 100 °C. Attempts to prepare cationic species [Ln(NO(3))(2)L(3)](+)[PF(6)](-) have not been totally successful and led to the isolation of crystals of Lu(NO(3))(3)L(2) and Tb(NO(3))(3)L(2).CH(3)CN (8).

Digitally captured signatures: A method for the normalization of force through calibration and the use of the zeta function.

Digitally captured signatures (DCS) are entering the scope of the Forensic Handwriting Examiner (FHE), and the meaningful comprehension and comparison of the captured information is essential in order to proceed to the examination of authenticity of DCS. In DCS solutions, force is captured and presented as pressure levels, but the relation between exercised force and the assigned pressure levels is not provided by the manufacturers of these solutions. For this purpose, we constructed an experimental array that allows the correlation of exercised force and assigned pressure levels, in a combination of three different digitizers, six different styli and four different capturing software. This process let us calculate the correlation function that assigns pressure levels to force for each solution (called the Zeta Function). Through this process, it was observed that different solutions follow different Zeta functions. To address this problem, a methodology for normalization of captured data between different solutions was created and demonstrated, using the calculated Zeta function and its inverse.

Lanthanide nitrate complexes of tri-isobutylphosphine oxide: solid state and CD2Cl2 solution structures.

The complexes Ln(NO(3))(3)L(3) between Ln(NO(3))(3) and (i)Bu(3)PO (=L) have been prepared for Ln = La-Lu (excluding Pm). The isolated complexes have been characterized by infrared spectroscopy, mass spectrometry, and elemental analysis. The single crystal X-ray structures have been determined for representative complexes across the series Ln = Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, and Yb and show the coordination geometry around the metal to be the same with 9-coordinate lanthanide ions and bidentate nitrates. Subtle changes in the coordination of the nitrate ligand occur from Sm onward. Changes in the infrared spectra correlate well with changes in the X-ray structures. Solution properties have been examined by variable temperature multinuclear ((1)H, (13)C, (15)N, and (31)P) NMR spectroscopy in CD(2)Cl(2). The spectra of complexes of the early lanthanides are consistent with the presence of a single species in solution while those of the heavier lanthanides show that more than one complex is present in solution and that two inequivalent phosphorus environments are observable at low temperature. The fluxional behavior is lanthanide dependent with smaller ions giving static structures at higher temperature. Complexes with tricyclohexylphosphine oxide show that the dynamic NMR behavior is also related to the size of the ligand. Analysis of the lanthanide induced shifts indicates minor changes in solution structure occur from Sm onward which correlate well with the solid state structures.

A statistical study of the relative difficulty of freehand simulation of form, proportion, and line quality in Arabic signatures.

This article compares the skill with which a large sample of Arabic writers was able to simulate different handwriting elements in two Arabic signatures. The data agree with the consensus of experts about Roman script: Form is significantly better simulated than Proportion, and Proportion is significantly better simulated than Line Quality. The fact that patterns long observed in Roman script simulation can be statistically demonstrated to exist in the simulation of Arabic signatures suggests that these may be widespread, if not universal, patterns of simulation among writing systems. This is also supported by similar results from a study of abstract characters (Leung et al. 1993), which suggests that these tendencies may even transcend linguistic writing systems. Among the Proportional elements are slant, alignment, spacing, and size.

Manganese(II) and cobalt(II) complexes of 1,4-bis(diphenylphosphinoyl)butane.

The title complexes, catena-poly[[[diaquadiethanolmanganese(II)]-mu-1,4-bis(diphenylphosphinoyl)butane-kappa(2)O:O'] dinitrate 1,4-bis(diphenylphosphinoyl)butane solvate], {[Mn(C(2)H(6)O)(2)(C(28)H(28)O(2)P(2))(H(2)O)(2)](NO(3))(2).C(28)H(28)O(2)P(2)}(n), (I), and catena-poly[[[diaquadiethanolcobalt(II)]-mu-1,4-bis(diphenylphosphinoyl)butane-kappa(2)O:O'] dinitrate 1,4-bis(diphenylphosphinoyl)butane solvate], {[Co(C(2)H(6)O)(2)(C(28)H(28)O(2)P(2))(H(2)O)(2)](NO(3))(2).C(28)H(28)O(2)P(2)}(n), (II), are isostructural and centrosymmetric, with the M(II) ions at centres of inversion. The coordination geometry is octahedral, with each metal ion coordinated by two trans ethanol molecules, two trans water molecules and two bridging 1,4-bis(diphenylphosphinoyl)butane ligands which link the coordination centres to form one-dimensional polymeric chains. Parallel chains are linked by hydrogen bonds to uncoordinated 1,4-bis(diphenylphosphinoyl)butane molecules, which are bisected by a centre of inversion. Further hydrogen bonds, weak C-H...O interactions to nitrate anions, and weak C-H...pi interactions serve to stabilize the structure. This study reports a development of the coordination chemistry of bis(diphenylphosphinoyl)alkanes, with the first reported structures of complexes of the first-row transition metals with 1,4-bis(diphenylphosphinoyl)butane.

The preparation, characterisation and in vitro cytotoxicity of potentially chemotherapeutic heterobimetallic complexes containing early and late transition metals.

The reactions of phosphine Ph(2)P(CH(2))(2)SO(3)Na with Cp(2)M'Cl(2) (M'=Ti, Zr) in aqueous solution give the metallophosphines, Cp(2)Ti(OSO(2)(CH(2))(2)PPh(2))(2) (Cp=cyclopentadienyl) and CpZr(OH)(OSO(2)(CH(2))(2)PPh(2))(2). These react with CODM"Cl(2) (M"=Pd, Pt) (COD=1,5-cyclooctadiene) in dichloromethane to give heterobimetallic complexes Cp(2)Ti(OSO(2)(CH(2))(2)PPh(2))(2)M"Cl(2) and CpZr(OH)(OSO(2)(CH(2))(2) PPh(2))(2)M"Cl(2) respectively. The compounds are characterised by infrared and NMR spectroscopies and elemental analysis. Electrospray mass spectra of the complexes are reported and compared to those of Cp(2)M'Cl(2) in water and dimethylsulfoxide (DMSO). For zirconocene dichloride and its product heterobimetallic complexes, the addition of ethylenediamine tetraacetic acid disodium salt (Na(2)H(2)EDTA) was found to be an effective ionisation enhancement agent for the electrospray mass spectral studies. Cytotoxicity studies for the previously reported Cl(2)Pt(PPh(2)(CH(2))(2)SO(3)H)(2).3.5H(2)O (Wedgwood et al., Inorg. Chim. Acta 290 (1999) 189), and the compounds Cp(2)Ti(OSO(2)(CH(2))(2) PPh(2))(2).1.5H(2)O and Cp(2)Ti(OSO(2)(CH(2))(2)PPh(2))(2)PtCl(2).4H(2)O reported here, have been evaluated by colony formation assay against cisplatin-sensitive and -resistant cell lines L929 and L929/R to highlight potential chemotherapeutic activity. The compound Cl(2)Pt(PPh(2)(CH(2))(2)SO(3)H)(2).3.5H(2)O overcomes cisplatin resistance.

Determination of the sequence of latent fingermarks and writing or printing on white office paper.

Latent fingermarks were deposited onto white office paper samples containing writing or printing from several media (for example, ballpoint pens and laser printers). Fingermarks were deposited both before and after writing/printing. The marks were then treated with appropriate latent fingermark development techniques. Once treated, they were examined with standard techniques applied in document examination (filtered light analysis, electrostatic detection device and Raman spectroscopy) to determine the sequence of application. The results suggested that the sequence of laser printing and latent marks could be determined via electrostatic detection device examination of undeveloped and Ninhydrin developed samples.

The influence of gender on ability to simulate handwritten signatures: a study of Arabic writers.

This study investigates whether a writer's gender can be determined from an inspection of simulated signatures written in the Arabic alphabet or Arabic abjad. It is generally believed that the penmanship of female writers is superior to male writers. There is also reason to expect that superiority in writing skill might contribute to success in simulating the signatures of other writers. Simulated signatures produced by a large population of male (414) and female (312) Arabic writers were graded, and the results were statistically analyzed. Women were found to have a marginal advantage simulating all elements of the signatures, but there was no statistically significant difference between the genders on any of the elements examined.

catena-Poly[[bis(nitrato-kappa(2)O,O')copper(II)]-mu-propane-1,3-diylbis(diphenylphosphine oxide)-kappa(2)O:O'].

The structure of the title complex, [Cu(NO(3))(2)(C(27)H(26)O(2)P(2))](n), consists of polymeric chains formed by propane-1,3-diylbis(diphenylphosphine oxide) ligands bridging between metal centres. The Cu atom lies on a twofold rotation axis and a further symmetry centre bisects the bridging bisphosphine dioxide ligand. The CuO(6) coordination geometry is a distorted octahedron, with the bidentate chelating nitrate groups adopting a cis configuration.

Complexes of lanthanide nitrates with bis(diphenylphosphino)methane dioxide.

The reactions of lanthanide nitrates, Ln(NO(3))(3), with bis(diphenylphosphino)methane dioxide, Ph(2)P(O)CH(2)P(O)Ph(2) (L), lead to complexes with three distinct classes of structure. At low ratios of Ln:L (<1:1.5) in acetonitrile the ionic complexes [Ln(NO(3))(2)L(2)](+)[Ln(NO(3))(4)L](-) (Ln = Pr, Eu) have been isolated. When carried out with a 1:2 or higher ratio in ethanol the reaction yields Ln(NO(3))(3)L(2) (Ln = La,Ce) and [Ln(NO(3))(2)L(2)H(2)O](+)[NO(3)](-) (Ln = Nd, Gd, Ho). Geometrical isomerism is found for the cations [Ln(NO(3))(2)L(2)H(2)O](+) and is attributed to the extent of hydrogen bonding to the coordinated water. Ligand redistribution occurs on heating in the solid state giving yellow solids in all cases. Crystallization of these materials from ethanol or acetonitrile gives [Ln(NO(3))L(3)](2+).2[NO(3)](-), which have been structurally characterized for Ln = Gd and Yb. Electrospray mass spectra indicate that extensive ligand exchange reactions occur in solution.