Crystal structure and vibrational spectra of polyamine-copper(II) complexes

The structures of [Cu(en)(H₂O)₂]SO₄ (I), [Cu(en)₂](NO₃)₂ (II) and [Cu(trien)I]I (III) have been determined by single crystal X-ray diffraction. ComplexI is monoclinic, space group C2/c, with unit cell parametera=7.232(1),b=11.725(2),c=9.768(1), =105.50(1)°, andZ=4. ComplexII is also monoclinic, space group P2₁/a, witha=7.978(2),b=9.982(4),c=8.218(3), =111.11(2)°, andZ=2. ComplexIII is orthorhombic, space group P2₁2₁2₁, witha=8.098(1),b=11.902(1),c=13.682(2), andZ=4. The structures were solved by direct methods and refined by full-matrix least-squares to finalR values of 0.031, 0.043 and 0.036 for complexesI, II, andIII, respectively. ComplexesI andII show an octahedral coordination geometry. ComplexIII shows a square pyramidal coordination geometry. ComplexI forms infinite monodimensional chains where the SO ₄ ^2– ions acts as a bridge between two neighboringen molecules. The vibrational spectra of these complexes agree well with their crystal structures. Structure and stability of seven other related Cu(II) complexes of (trien), (dien)₂, (en)₂ and (en) are inferred in this study.     

Chelated aluminum alkoxides

The present contribution will demonstrate that monomeric alkoxide compounds can be formed by the use of the Salen(tBu) ligand. These alkoxides, LAlOR (with L=Salen (tBu), R=Me (1), Salomphen(tBu), R=Me (3) and L=Salen(tBu), R=Et (4)) feature five-coordinate monomeric aluminum (Salen(tBu)=N,N-ethylenebis(3,5-di-tert-butylsalicylideneimine) and Salomphen(tBu)=N,N-(4,5-di-methyl)phenylenenebis(3,5-di-tert-butylsalicylideneimine). Crystallization of 1 from MeOH affords the six-coordinate complex, Salen(tBu)AlOMe(MeOH) (2). The manner in which these compounds may be obtained, as well as the structures of 2 and 4 will be described     

Synthesis and crystal structure of Bi(mpo)3 (Hmpo = 2-mercaptopyridine N-oxide)

The synthesis as well as crystal and molecular structure of [Bi(C₅H₄NOS)₃] are reported. The complex crystallizes in the monoclinic system, space group P2₁/n with lattice parameters a = 9.6521(3) Å, b = 10.0659(4) Å, c = 18.4484(7) Å, = 102.13(6)°, and D _calc = 2.227 Mg · m^–3 for Z = 4. It is clear from the packing diagram that the title compound is a dimer via the secondary coordination. Surrounding Bi atom, three five-membered ring planes (Bi,O,N,C,S) make a dihedral angle of 55.91, 54.72, and 26.13° respectively. The whole crystal presents a three-dimensional network structure as each molecule produces four weak C–H O hydrogen bonds and a weak C–H S hydrogen bond.     

Reaction of 2,3-bis(diphenylphosphino)maleic acid-thioanhydride (bmata) with PhCCo3(CO)9. X-ray diffraction structure of {\text{Co}}_{\text{3}} ({\text{CO)}}_{\text{6}} [\mu _2 ,\eta ^2 ,\eta ^1 {\text{ - C(Ph)}}{\text{(O)](}}\mu _2 {\text{ - PPh}}_{\text{2}} )

The benzylidyne-capped cluster PhCCo₃(CO)₉ (1) reacts with the diphosphine ligand 2,3-bis(diphenylphosphino)maleic acid-thioanhydride (bmata) to afford ultimately the new cluster ${\text{Co}}_{\text{3}} ({\text{CO)}}_{\text{6}} [\mu _2 ,\eta ^2 ,\eta ^1 {\text{ - C(Ph)}}{\text{(O)](}}\mu _2 {\text{ - PPh}}_{\text{2}} )$ (3) in low yield under thermolysis conditions or by Me₃NO activation of PhCCo₃(CO)₉. The intermediate cluster compound PhCCo₃(CO)₇(bmata) (2) has been confirmed by IR spectroscopy and is shown to give ${\text{Co}}_{\text{3}} ({\text{CO)}}_{\text{6}} [\mu _2 ,\eta ^2 ,\eta ^1 {\text{ - C(Ph)}}{\text{(O)](}}\mu _2 {\text{ - PPh}}_{\text{2}} )$ upon heating. Cluster 3 has been isolated and characterized in solution by IR and ³¹P NMR spectroscopies, and the solid-state structure of 3 was established by X-ray diffraction analysis. ${\text{Co}}_{\text{3}} ({\text{CO)}}_{\text{6}} [\mu _2 ,\eta ^2 ,\eta ^1 {\text{ - C(Ph)}}{\text{(O)](}}\mu _2 {\text{ - PPh}}_{\text{2}} )$ crystallizes in the triclinic space group P ${\bar 1}$ , a = 11.6053(8) Å, b = 11.8438(8) Å, c = 15.099(1) Å, α = 105.169(5)^○, β = 90.530(5)^○, γ = 104.976(6)^○, V = 1928.5(2) ų, Z = 2, and d _calc = 1.578; R = 0.0442, R _w = 0.481 for 2591 observed reflections with I > 3σ (I). The cyclic voltammetric properties of 3 have been investigated and are contrasted with the related bma-derived cluster ${\text{Co}}_{\text{3}} ({\text{CO)}}_{\text{6}} [\mu _2 ,\eta ^2 ,\eta ^1 {\text{ - }}{\text{(O)OC(O)](}}\mu _2 {\text{ - PPh}}_{\text{2}} )$ .     

Exponential stability in thermoviscoelastic mixtures of solids

In this paper we investigate the asymptotic behavior of solutions to the initial boundary value problem for a one-dimensional mixture of thermoviscoelastic solids. Our main result is to establish the exponential stability of the corresponding semigroup and the lack of exponential stability of the corresponding semigroup.     

Geometric Approach to Pontryagin’s Maximum Principle

Since the second half of the 20th century, Pontryagin’s Maximum Principle has been widely discussed and used as a method to solve optimal control problems in medicine, robotics, finance, engineering, astronomy. Here, we focus on the proof and on the understanding of this Principle, using as much geometric ideas and geometric tools as possible. This approach provides a better and clearer understanding of the Principle and, in particular, of the role of the abnormal extremals. These extremals are interesting because they do not depend on the cost function, but only on the control system. Moreover, they were discarded as solutions until the nineties, when examples of strict abnormal optimal curves were found. In order to give a detailed exposition of the proof, the paper is mostly self-contained, which forces us to consider different areas in mathematics such as algebra, analysis, geometry.     

Polymerization of Styrene by Neutral Ni (II) Acetylide Complex

Over the past few years, the utilization of late transition metal-based soluble complexes as styrene polymerization catalysts has received considerable attention1. Various systems have been explored. For example, cationic h3-allylnickel complexes alone2 or modified by P (III) ligands3 as well as a few other systems (e. g., cationic h3-benzylic nickel complexes4) are active homogeneous catalysts for the low molecular weight polymerization of styrene by simple cationic mechanism2,3,4. Neut…     

CuI晶体缺陷态电子结构及其施主-受主对发光机理的研究

运用相对论密度泛函理论和嵌入分子团簇方法，模拟计算了具有γ相CuI晶体的本征缺陷态电子结构.结果表明，四面体间隙Cu和Cu空位最有可能在禁带中引入浅施主和受主能级，从而形成施主-受主对(DAP)，产生420—430 nm的DAP复合发光. 关键词： γ-CuI晶体 密度泛函理论 电子结构 发光机理     

PARTITION PROPERLY OF DOMAIN DECOMPOSITION WITHOUT ELLIPTICITY

1. IntroductionDomain decomposition methods have undergone great development in the past decade andthere has been rich mathematical theory for model problems. It is worthy to examine how theSemethods can be effectively applied to predical problems where the model problem analysis doesnot trivially apply. It is far from of~ng that there remains not much new for domain decomposition theoretically and Practically. In terms of domain partition, domain decompositionmethods are claSsiced as twO ir…     

Photorefractive properties and self-pumped phase conjugation in a series of BaTiO3 crystals

This paper presents the experimental results of two-wave mixing and self-pumped phase conjugation (SPPC) in barium titanate (BaTiO₃) crystals doped with Rh or Ce. It has been shown that the main parameters of SPPC depend very strongly on the concentrations of dopants, the incident angles and the crystal cut used. High gain in two-wave mixing corresponds to low phase-conjugate reflectivity in all samples. It is impossible to maintain the highest reflectivity and gain simultaneously, because the gain will definitely be limited when we try to get the highest reflectivity, and vice versa. Some qualitative explanation of the experimental results is also given. Received: 5 January 2001 / Final version: 25 May 2001 / Published online: 19 September 2001