Volume 78, Issue 9-10

A new complex [RuCl 2 (dppf)(PN)] 1 (dppf = 1,1′-bis(diphenylphosphino) ferrocene; PN = (2-diphenylphosphino)benzenamine) has been synthesized and characterized. Its structure was determined by single-crystal X-ray diffraction. An efficient 1 /Pd salt-cocatalyzed three-component oxidation/cyclization/Suzuki reaction for the synthesis of 2-pyridinyl-6-arylquinolines from 2-acetylpyridine, (2-amino-5-bromophenyl)methanol, and arylboronic acids has been developed.

A mononuclear Mn(II) complex [Mn( p -MOPhH 2 IDC) 2 (H 2 O) 2 ]·2(DMF), was synthesized by the reaction of p -MOPhH 3 IDC (2-(4-methoxyphenyl)-1 H -imidazole-4,5-dicarboxylic acid) and Mn(CH 3 COO) 2 ·4H 2 O under solvothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR and UV–vis spectroscopy. The structure analysis revealed that the manganese(II) center has a six-coordinated octahedral coordination geometry. The performance of a Mn(II) complex-doped carbon paste electrode (Mn-CPE) in the electrocatalytic hydrogen evolution reaction (HER) was evaluated by linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) methods. The polarization curve shows that the η 10 298K (overpotential, 10 mA cm −2 ) of the Mn-CPE was positively shifted by 341 mV compared with the bare CPE (without complex). The Tafel slope of the Mn-CPE was 161 mV dec −1 . These data indicate that the Mn-CPE was effective in the HER electrocatalytic reaction. For EIS experiments, the arc diameter of the high-frequency region of the Mn-CPE was much smaller than that of the bare CPE, which further indicates the effective catalytic capacity of the Mn(II) complex for hydrogen evolution. The information obtained from this study will help to expand the application of Mn(II) complexes in the field of electrochemistry.

The new quaternary lithogallate Sr 2 LiGaO 4 was prepared by conventional solid-state synthesis in a welded tantalum ampoule at T  = 850 °C. Single-crystal X-ray diffraction was used to elucidate the crystal structure of the compound, which crystallizes in the orthorhombic space group Pnma (no. 62) with the lattice parameters a  = 11.2434(4), b  = 5.6879(2), and c  = 6.6983(2) Å. The phase composition of the powder sample was determined by Rietveld refinement based on X-ray diffraction data. The crystal structure is composed of layers of corner-sharing LiO 4 and GaO 4 tetrahedra with alternating orientation parallel to the crystallographic bc plane. The eightfold coordinated strontium atoms are arranged in a zigzag manner between the layers forming two types of double-capped trigonal prismatic SrO 8 units with common faces. The crystal structure of Sr 2 LiGaO 4 is isotypic to that of the lithoaluminate derivate Sr 1.85 Ba 0.15 LiAlO 4 .

The two compounds Fe 2 B 3 O 7 ( a  = 663.61(4), c  = 438.39(3) pm, space group: P 4 ‾ $\overline{4}$ 2 1 m ) and Mn 4 (B 6 O 13 (OH)) ( a  = 445.14(1), b  = 683.56(2), c  = 1330.34(3) pm, β  = 90.42(1)°, space group: P 2 1 / c ) were synthesized under high-pressure/high-temperature conditions of 9 GPa and 800 °C. Their crystal structures have been determined via single-crystal X-ray diffraction and the occurring side-phases have been identified. Fe 2 B 3 O 7 crystallizes in the melilite structure type, whereas the novel structure of Mn 4 (B 6 O 13 (OH)) can be derived from the structures of the minerals melilite or johachidolite.

Twenty five new ternary Laves phases RET 4 Mg and RET 4 Cd ( RE = rare earth element; T = Co, Ni, Cu, Pt) have been synthesized from the elements using niobium or tantalum tubes as inert crucible materials. The lattice parameters have been derived from powder X-ray diffraction data. The structures of Ce 1.41(1) Co 4 Mg 0.59(1) , Dy 1.10(1) Co 4 Mg 0.90(1) , LaPt 4 Cd, Y 1.10(1) Cu 4 Cd 0.90(1) , Ca 0.93(1) Cd 0.07(1) Pd 2 and Eu 0.87(2) Cd 0.13(2) Pd 2 were refined from single-crystal X-ray diffractometer data. Most phases show certain degrees of RE /Mg or RE /Cd disorder. The quenched phases are assigned to the MgCu 2 structure, while the annealed ones adopt the MgCu 4 Sn type, a translationengleiche superstructure variant of the aristotype. The annealing time has a substantial influence on the degree of ordering and is expressed in the lattice parameters, i.e. larger ones for the disordered samples. The RE Pt 4 Cd ( RE = La–Nd) samples have been characterized with respect to their magnetic properties. LaPt 4 Cd is a diamagnet, while CePt 4 Cd (2.23(1) µ B ), PrPt 4 Cd (3.40(1) µ B ) and NdPt 4 Cd (3.43(1) µ B ) are Curie–Weiss paramagnets. The cerium compound shows a slight moment reduction. NdPt 4 Cd is ordered ferromagnetically at T C = 4.4(1) K.

Single crystals of Y 3 Ru were obtained as a side product during phase analytical studies of yttrium-rich compounds in the system Y–Ru–Zn. The structure of Y 3 Ru was refined from single-crystal X-ray diffractometer data: Fe 3 C type, Pnma , a = 732.51(7), b = 925.61(8), c = 633.66(10) pm, w R = 0.0639, 811 F 2 values, 23 variables. The ruthenium atoms have coordination number 9 in form of a strongly distorted tricapped trigonal yttrium prism with Ru–Y distances ranging from 275–391 pm. The second substructure concerns empty Y 6 octahedra ( d (Y–Y) = 344–396 pm). Electronic structure calculations show a net charge transfer from yttrium to ruthenium and underpin the essentially covalent Y–Ru bonding. A phase-pure sample of Y 3 Ru was synthesized from the elements by arc-melting. Temperature-dependent magnetic susceptibility studies of this sample reveal Pauli paramagnetism (3.6(1) × 10 −5  emu mol −1 at T = 300 K).

Crystals of t BuPCl 2 were obtained by a short-path sublimation at 80 °C/0.150 mbar. The structure determination of t BuPCl 2 was based on X-ray powder data. The measurements were carried out in a temperature range from 173 K to r. t. At 173 K the X-ray powder pattern has been assigned to an orthorhombic phase, and that at 213 K to a plastic-crystalline, cubic phase. We further investigated the reactivity of t BuPCl 2 towards Na(thf) 2 [Si t Bu 3 ] at ambient temperature. The reaction of t BuPCl 2 with two equivalents of Na(thf) 2 [Si t Bu 3 ] gave together with t Bu 3 SiCl the yet unknown phosphanediide Na 2 [P t Bu] by a chlorine-sodium exchange. The identity of Na 2 [P t Bu] was confirmed by 31 P NMR spectroscopy and its existence was unambiguously demonstrated by its protonation with methanol and the consequent formation of t BuPH 2 .

The reactions of copper, silver and palladium salts with the homochiral ligands 3,3′-bis[( S , S )-4-isopropyl-2-oxazolyl]-4-chloro-2,2′-bipyridine (L 1 ), 3,3′-bis[( S , S )-4-benzyl-2-oxazolyl]-4-chloro-2,2′-bipyridine (L 2 ) and 2-[( S )-4-isopropyl-2-oxazolyl]quinoline (L 3 ) yield three new chiral complexes: [Cu(L 1 )Br 2 ] ( 1 ), [Ag(L 2 )(CH 3 CN)]·(BF 4 )·(CH 3 OH) 0.17 ·(H 2 O) 0.08 ( 2 ) and [Pd(L 3 )Cl 2 ]·(CH 3 COCH 3 ) 0.5 ( 3 ), which have been characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental and thermogravimetric analyses. The complexes 1 – 3 display discrete mononuclear structures. Non-linear optical properties of complexes 1 – 3 were investigated.