V. Manríquez

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), β=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), β=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 SO42− 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.

PLANAR OR TETRAHEDRAL COORDINATION IN COPPER(II) COMPLEXES INDUCED BY BROMO SUBSTITUTION

Abstract The diffraction study of bis(5-bromo-N-m-tolylsalicylaldiminate)copper(II) shows the copper atom in a centrosymmetric position and the two ligands displayed trans to each other in a planar environment. Two additional weak interactions due to Br atoms (Jahn-Teller effect) of neighboring units complete the coordination sphere, CuBr = 3.662(2) A , so that the comple is formally a polynuclear two-dimensional species. On the contrary, bis(3,5-dibromo-N-p-tolylsalicylaldiminate(copper(II) is mononuclear and shows only the two ligands coordinated and the geometry is distorted ‘tetrahedral’. The distortion is due to intramolecular repulsion interactions. Electronic spectra of these two compounds show a single asymmetric band at 700 nm for the former, and two bands located at 650 and 850 nm for the latter. Both compounds are monoclinic, space group P2 1 /c with a = 9.919(2) A , b = 10.965(2) A , c = 12.283(2) A , β = 105.88(1)°, Z = 2 for the former, and a = 13.290(2) A , b = 12.195(2) A , c = 17.891(2) A , β = 105.38(1)°, Z = 4 for the latter.

Spectra and structure of polyamine-copper(II) complexes. Infrared spectrum and normal coordinate calculations of mono(diethylenetriamine) copper(II) nitrate

Abstract The infrared spectrum of mono(diethylenetriamine)copper(II) nitrate has been obtained in the frequency range 4000-80 cm −1 . Assignments of fundamental frequencies in the coordination site, as well as in the free and bonded nitrates, were performed regarding the structure of the complex. Also, a normal coordinate analysis based on a simplified model, was carried out in order to distinguish the frequency position of some normal modes, such as the three different ν(CuN) and the two different ν(CuO) modes.

N-(Substituted phenylhydroxynaphthylaldiminate) nickel(II) complexes: A structural and vibrational study

Abstract The crystal and molecular structure of bis-( N -phenyl-1-hydroxy-2-naphthylaldiminate) nickel(II) ( 1 ) have been determined by x-ray crystallography. The compound crystallizes in the triclinic space group P 1, No. 2 with one molecule in the unit cell. The metal adopts a trans -planar tetracoordination geometry with N and O as electron donor atoms. The molecule is stepped with the planes of two naphthyl groups parallel, each one making a dihedral angle of 20.4° with the coordination plane. The infrared spectrum and a normal coordinate treatment, based on a simplified molecular model, are discussed and related to the crystal structure. The bands near 390 and 290 cm −1 have been assigned to the Ni O and Ni N stretching vibrations, respectively. The corresponding force constants were estimated to be 1.28 and 0.78 mdyn A −1 . The influence of variation of the nature of the Schiff base ligand on structure 1 has been studied by including in the vibrational analysis the bis- N -(Y-phenyl)-2-hydroxy-1-naphthylaldiminate nickel(II) complexes, where substituents Y are o -OCH 3 ( 2 ), m -OCH 3 ( 3 ) and m -NO 2 ( 4 ). The results indicated a slightly lower electronic density distribution on the chelate ring in complex 1 , particularly on the Ni O bond, suggesting a stability order 1 ≈ 2 − 4 . This difference arises mainly from the position of the hydroxynaphthylaldiminate group.

Dicyclohexylamine-Thiourea Clathrate

Abstract The reaction of dicyclohexylamine (DCHA) with thiourea leads to the formation of the inclusion compound DCHA(6 Thiourea). Room temperature, single crystal X-ray diffraction analysis shows the product has a trigonal structure, α=β=90°, γ=120°, a=b=15.801(2)A, c=12.451(3)A, which may be described as a thiourea matrix defining hexagonal cavities where the di-cyclohexylamine molecules are accommodated. 13C-cross polarization magic angle spinning (CP-MAS) NMR study indicates the guest inside the cavities has a relatively free rotation and that the channels are, concerning this amine, perfect van der Waals cavities. Thermal studies indicates that the structural identity of the thiourea matrix endures after a partial loss of amine.

Intercalation of polyaniline in the layered materials mps3, m = Mn, Cd

Abstract The intercalation compounds (Polyaniline) 1.08 Mn 0.86 PS 3 and (Polyaniline) 0.57 Cd 0.73 PS 3 have been synthesized by the ion-exchange procedure. These compounds constitute a new family of intercalates in MPS 3 (M = Mn, Cd) host layer, with Polyaniline as guest species. They have been characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), differential thermal analysis (DTA), thermogravimetric analysis (TGA), and electrical conductivity measurements. Both intercalation compounds show values of electrical conductivity (σ i ) of about 10 −7 Ω −1 cm −1 at 298 K and photoconductivity at temperatures from 296 to 343 K.

Physical properties of the cation-mixed M′MPS3 phases

Abstract The cation-mixed compounds Cd0.5Fe0.5PS3, Cd0.5Mn0.5PS3, Fe0.5Mn0.5PS3, and Fe0.5Ni0.5PS3 have been synthesized from the corresponding elements at 1023 K. These compounds have been characterized by powder X-ray diffraction, conductivity, and magnetic susceptibility measurements. The conductivity at room temperature of the M′MPS3 phases lies between the conductivity values for the corresponding end-member phases MPS3. The magnetic measurements show that the magnetic interaction of the MPS3 phases is retained in the mixed phases, but the magnetic order is weakened due to the disordered arrangements of the metal ions in M′MPS3 phases.

Single-crystal Anisotropic Proton Conductivity in the Clathrate of the Hydrogen-diquinuclidine Ion Inserted in a Polyanionic Thiourea–chloride Matrix

The anisotropic proton conductivity of a large-sized single crystal of the supramolecular, commensurate host–guest inclusion compound constituted by a polyanionic thiourea–chloride matrix defining channels in which the diquinuclidinium cations [Q2H]+ are hosted is reported. Specimens in the millimetre scale display an anisotropy factor of about 100, with electrical conductivities along molecular channels of the order of 10-4 S cm-1 at room temperature.

Insertion of In(III) and Ga(III) into MPS3 (M = Mn, Cd) layered materials

Abstract In 0.20 Mn 0.70 PS 3 , Ga 0.28 Cd 0.58 PS 3 and In 0.33 Cd 0.50 PS 3 compounds were synthesized by insertion of trivalent cations (In 3+ and Ga 3+ ) into MPS 3 (M = Mn, Cd). The insertion process requires the previous intercalation of K + ions into these matrices, giving rise to new materials belonging to the MPS 3 family. Such compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) microprobe, differential thermal and thermogravimetric analyses (DTA/TGA), magnetic susceptibility measurements, and electrochemical impedance spectroscopy. It is inferred that the trivalent cations were incorporated, rather than intercalated, into the intralamellar region, i.e., the cations were located in the interlamellar space, following the typical topotactic ion-exchange processes of the monovalent cations. Clement and Michowicz reported a similar case for Ni 2+ insertion into MnPS 3 in 1984.

Inclusion of a Protonated Amine in Thiourea-Chloride and -Bromide Matrix. Expected Ionic Conducting Materials

The reaction of thiourea with 1-azabicyclo[2,2,2]octane (quinuclidine) and quinuclidine hydrochloride or quinuclidine hydrobromide in ethanol/acetone mixture leads to the formation of the inclusion compounds (thiourea) 2 [(quinuclidine) 2 H] + Cl − and (thiourea) 2 [(quinuclidine) 2 H] + Br − , respectively. The crystal structure of the ternary proton-amine-thiourea complex may be described as the inclusion of the hydrogen-diquinuclidine cationic complex in a stacked form in the van der Waals cavities of a polyanionic thiourea-chloride and −bromide superstructure. Complete structure determination of the products was performed and show channel structure formed by monodimensional, non intersecting polimeric chains of thiourea molecules linked by chloride or bromide ions.