Octahedra-Tilted Control of Displacement Disorder and Dielectric Relaxation in Mn-Doped SrTiO Single Crystals.

Strontium titanate SrTiO (STO) is a canonical example of a quantum paraelectric, and its doping with manganese ions unlocks its potential as a quantum multiferroic candidate. However, to date, the specifics of incorporation of the manganese ion into the perovskite lattice and its impact on structure-property relationships are debatable questions. Herein, using high-precision X-ray diffraction of a Mn (2 atom %)-doped STO single crystal, clear fingerprints of the displacement disorder of Mn cations in the perovskite B-sublattice are observed.

Synthesis of Perovskite-Type BiScO Ceramics and their Dielectric and Infrared Characterization.

BiScO compound was obtained in the form of dense ceramic with a perovskite-type structure, and its complex characterization was determined for the first time. The corresponding synthesis procedure is described in detail. It is demonstrated that the temperature region of the phase stability at atmospheric pressure lies at < 700 °C (973 K).

Polar Order and Frustrated Antiferromagnetism in Perovskite Pb2MnWO6 Single Crystals.

Single crystals of the multiferroic double-perovskite Pb2MnWO6 have been synthesized and their structural, thermal, magnetic and dielectric properties studied in detail. Pure perovskite-phase formation and stoichiometric chemical composition of the as-grown crystals are confirmed by X-ray single-crystal and powder diffraction techniques as well as energy-dispersive X-ray and inductively coupled plasma mass spectrometry. Detailed structural analyses reveal that the crystals experience a structural phase transition from the cubic space group (s.

Expanded-ring N-heterocyclic carbenes efficiently stabilize gold(I) cations, leading to high activity in π-acid-catalyzed cyclizations.

A series of six- and seven-membered expanded-ring N-heterocyclic carbene (er-NHC) gold(I) complexes has been synthesized using different synthetic approaches. Complexes with weakly coordinating anions [(er-NHC)AuX] (X(-) = BF4(-), NTf2(-), OTf(-)) were generated in solution. According to their (13)C NMR spectra, the ionic character of the complexes increases in the order X(-) = Cl(-) < NTf2(-) < OTf(-) < BF4(-).

Expanded ring diaminocarbene palladium complexes: synthesis, structure, and Suzuki-Miyaura cross-coupling of heteroaryl chlorides in water.

A series of new 6- and 7-membered N-heterocyclic carbene (NHC) complexes of palladium (NHC)Pd(cinn)Cl (cinn = cinnamyl = 3-phenylallyl) were synthesized and characterized structurally in the solid state. The influence of ring size (5, 6 or 7) and bulkiness of N-aryl substituents (Mes = 2,4,6-trimethylphenyl, or Dipp = 2,6-diisopropylphenyl) in carbenes on palladium catalysed Suzuki-Miyaura cross-coupling was revealed. Due to the unique stereoelectronic properties of expanded ring NHCs, a versatile, highly efficient green protocol of coupling of heteroaromatic chlorides and bromides with boronic acids has been developed.

Dual reactivity of N-heterocyclic carbenes towards copper(II) salts.

Complexes of N-heterocyclic carbenes (NHCs) with copper(II) halogenides are unstable. Upon formation, these complexes decompose to give haloamidinium salts. Contrastingly, O-substituted copper(II) NHC complexes are fairly stable.

Dakin-West trick in the design of novel 2-alkyl(aralkyl) derivatives of oxazolo[3,2-a]pyridines.

A series of previously unavailable derivatives of 2-alkyl- and 2-benzylderivatives of oxazolo[3,2-a]pyridines III were obtained via tandem ring opening and ring closure from stable mesoionic 3-acyloxazolo[3,2-a]pyridinium-2-olates I. The key intermediates of this tandem transformation are N-(b-oxoethyl)pyridones-2 II obtained by Dakin-West acylation of (pyridone-2-yl-1)acetic acid. An example of further utilization of this strategy is illustrated by preparation of unknown 2-benzylimidazo[1,2-a]pyridine from the salt I and ammonia.