Copper(II) and nickel(II) complexes of 2-formylpyridine 3-piperidinyl-, 3-hexamethyleneiminyl- and 3-azabicyclo[3.2.2]nonylthiosemicarbazones

Summary Copper(II) and nickel(II) complexes of 2-formylpyridine 3-piperidinyl-, 3-hexamethyleneiminyl- and 3-azabicyclo-[3.2.2]nonylthiosemicarbazones were prepared and characterized spectroscopically. ¹H and ¹³C n.m.r. spectra of the thiosemicarbazones and a diamagnetic nickel(II) complex are reported, together with i.r., electronic and e.s.r. spectra of the metal complexes. The thiosemicarbazones and their copper(II) and nickel(II) complexes exhibit considerable growth inhibitory activity against Paecilomyces variotii, but show minimal activity against Aspergillus niger.     

Molecular structure and spectral properties of bromo(2-acetylpyridine4 N-methylthiosemicarbazonato)copper(II)

Summary The anion (loss of³ N hydrogen) of 2-acetylpyridine⁴ N-methylthiosemicarbazone coordinates in a planar conformation to copper(II) through the pyridyl nitrogen, azomethine nitrogen and thiolato sulphur atoms. The fourth coordination site is occupied by a bromo ligand and the complex is mononuclear and essentially planar. Bond distances and angles, as well as solid state and solution spectral properties, are compared to other recently reported copper(II) thiosemicarbazone complexes.     

Spectral and biological studies of copper(II) complexes of 2-acetyl-pyridine thiosemicarbazones with bulky 4N-substituents

Summary Copper(II) complexes of a large number of 2-acetylpyridine ⁴N-alkyl thiosemicarbazones were prepared and characterized. I.r., electronic and e.s.r. spectra of the complexes, as well as ¹H and ¹³C n.m.r. spectra of the thiosemicarbazones, were obtained. Both the thiosemicarbazones and their complexes show either modest or no growth inhibitory activity against Aspergillus niger, but many have considerable activity against Paecilomyces variotii. There is a relationship between the antifungal activity and size of the ⁴N-substituent for both the thiosemicarbazones and their copper(II) complexes.     

Nickel(II) and copper(II) complexes of 2-acetylpyridine 4 N-(2-methylpyridinyl)-, 4 N-(2-ethylpyridinyl)- and 4 N-methyl(2-ethylpyridinyl) thiosemicarbazones

Summary Ni^II and Cu^II complexes of 2-acetylpyridine ⁴ N-(2-methylpyridinyl)-, ⁴ N-(2-ethylpyridinyl)- and ⁴ N-methyl(2-ethylpyridinyl) thiosemicarbazones (HL4pam, HL4pae, and HL4Mpae, respectively) of general formula [M(HL)X₂] have been isolated from boiling EtOH and characterized by physico-chemical and spectroscopic methods. The growth inhibition activities of the thiosemicarbazones and their complexes were measured against Aspergillus nicer and Paecilomyces variotii.     

Capitalizing on <Emphasis Type="Italic">live</Emphasis> variables: new algorithms for efficient Hessian computation via automatic differentiation

We revisit an algorithm [called Edge Pushing (EP)] for computing Hessians using Automatic Differentiation (AD) recently proposed by Gower and Mello (Optim Methods Softw 27(2): 233–249, 2012). Here we give a new, simpler derivation for the EP algorithm based on the notion of live variables from data-flow analysis in compiler theory and redesign the algorithm with close attention to general applicability and performance. We call this algorithm Livarh and develop an extension of Livarh that incorporates preaccumulation to further reduce execution time—the resulting algorithm is called Livarhacc. We engineer robust implementations for both algorithms Livarh and Livarhacc within ADOL-C, a widely-used operator overloading based AD software tool. Rigorous complexity analyses for the algorithms are provided, and the performance of the algorithms is evaluated using a mesh optimization application and several kinds of synthetic functions as testbeds. The results show that the new algorithms outperform state-of-the-art sparse methods (based on sparsity pattern detection, coloring, compressed matrix evaluation, and recovery) in some cases by orders of magnitude. We have made our implementation available online as open-source software and it will be included in a future release of ADOL-C.     

Canonical two‐range addition theorem for slater‐type orbitals

The radial Slater‐type orbitals (STO) ${r^\mu }{e^{ - \alpha r}}$ can be simply obtained by repeated parametric differentiation of the Yukawa Potential $({e^{ - \alpha r}}/r)$ with respect to α. A new compact two‐range addition theorem (AdT) for the STO is herein derived by explicit parametric differentiation of the well‐known Yukawa AdT. The resulting addition formula is combined with the single‐range AdT for solid spherical harmonics $({r^l}Y_l^m(\hat r))$ to present a new AdT for three‐dimensional spherical coordinate STOs. We advance the proposition that this formula is “canonical” in the same sense that the Laplace expansion of the Coulomb potential is considered canonical. We demonstrate how this procedure can be employed for all exponential‐type orbitals. © 2012 Wiley Periodicals, Inc.     

Spectral studies of cobalt(III) complexes of heterocyclic 3-azacyclothiosemicarbazones and the structure of the acetylpyrazine 3-azabicyclo[3.2.2]nonylthiosemicarbazone complex

Summary Cobalt(III) complexes of 2-acetylpyridine 3-pyrrolidinyl-,3-piperidinyl-, 3-hexamethyleneiminyl- and 3-azabicyclo-[3.2.2]nonylthiosemicarbazone, [Co(Lpo)₂]BF₄, [Co-(Lpip)₂]BF₄, [Co(Lhexim)₂]BF₄ and [Co(Lbcn)₂]BF₄, respectively; 2-formylpyridine 3-piperidinyl-, 3-hexa-methyleneiminyl- and 3-azabicyclo[3.2.2]nonylthiosemi-carbazone, [Co(pip)₂]BF₄, [Co(hexim)₂]BF₄ and [Co(bcn)₂]BF₄, respectively; and aceylpyrazine 3-aza-bicyclo[3.2.2]nonylthiosemicarbazone, [Co(Pzbcn)₂]BF₄, have been synthesized and their spectral properties measured. The¹H and¹³C-n.m.r. spectra show the uncomplexed thiosemicarbazones to be mixtures of as many as three isomers, and that the two ligands in the cobalt(III) complexes are nearly identical. The crystal structure of [Co(Pzbcn)₂]BF₄ shows the two ligands coordinated in a mer-configuration. Bond lengths and angles in this complex are compared with data previously reported for thiosemicarbazone complexes.     

Nuclear magnetic resonance spectral study of 2-acetylpyridine4 N-alkylthiosemicarbazones and their cobalt(III) complexes

¹H and¹³C n.m.r. spectra are reported for a series of 2-acetylpyridine⁴ N-alkylthiosemicarbazones in order to study the effect of increased size of the alkyl function on the ratio of isomers present in solution. Similarly, n.m.r. data for the bis(thiosemicarbazone)cobalt(III) complexes are included, as well as these complexes' ligand field parameters. TMC 2698