Single crystals of two new strontium iron rhodates, SrFe0.71Rh0.29O3 and Sr4Fe0.73Rh2.27O9, have been grown and structurally characterized. Single crystals of SrFe0.71Rh0.29O3 and Sr4Fe0.73Rh2.27O9 were grown from potassium carbonate melts. SrFe0.71Rh0.29O3 crystallizes in the cubic perovskite structure, space group Pm (3) over barm, with a = 3.9027(6) Angstrom. Sr4Fe0.73Rh2.27O9 crystallizes with trigonal symmetry in the space group P321, a = 9.6091(2) Angstrom and c = 7.9448(2) Angstrom, and is structurally related to the 2H-hexagonal perovskites. Sr4Fe0.73Rh2.27O9 contains two independent 1-D chains of face-sharing polyhedra with a sequence of two RhO6 octahedra and one Fe/RhO6 trigonal prism and strontium cations separating the chains. The growth conditions, structures and magnetic properties of these compounds are discussed. (C) 2004 Elsevier B.V. All rights reserved.

Two new fulvene ligands, L1 and L2, have been synthesized by an aroylation reaction of the cyclopentadienyl anion. The coordination chemistry of L1 and L2 was investigated. Two novel CpAg(I)-containing polymeric compounds, 1 ([Ag-4(L1)(2)(mu-H2O)(2)(SO3CF3)(4)](.)(mu-bis-eta(1)-C6H6))(H2O)-H-.) and 2 ([Ag-2(L-2)(H2O)(SO3CF3)(2)](.)0.5(C6H6)), have been synthesized. Compounds 1 and 2 have been fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The solid state structure of 1 features a macro-ring-containing one-dimensional chain motif. The solid state structure of 2 features a one-dimensional double-chain motif. These double chains are further cross-linked to each other via CpAg(SO3CF3)(2)AgCp ((AgAg)-Ag-... contact of 4.215(15) Angstrom) linkage into a novel 2-D network with large cavities (effective cross-section of ca. 21 x 9 Angstrom), in which the benzene guest molecules are located.

Single crystals of two new barium rhodates were grown from a molten potassium carbonate flux. The new rhodates, Ba(11)Rh(10)O(30) and Ba(32)Rh(29)O(87), are structurally related to the 2H-hexagonal perovskite structure and are characterized by pseudo one-dimensional chains of alternating face-sharing trigonal prisms and octahedra. The structures of Ba(11)Rh(10)O(30) and Ba(32)Rh(29)O(87) were solved using the 4D superspace group approach in Jana2000. Ba(11)Rh(10)O(30), with a repeat of nine RhO(6) octahedra followed by one RhO(6) trigonal prism, contains the longest chain sequence of face-sharing octahedra known for this 2H-perovskite related family of oxides. A structural analysis of these two compounds revealed clear trends in metal-metal distances and octahedral heights not previously identified for this family of oxides. The application of these trends toward the structure of the all-octahedra-containing end member of the structural series, the hypothetical 2H-BaRhO(3), enabled a prediction of its rhodium-rhodium distance, octahedral height, and lattice parameters.

Single crystals of both Ba7Li3RU4O20 and Ba4NaRu3O12 were grown from reactive molten hydroxide fluxes. Ba7Li3Ru4O20 is a 7L-layer perovskite-related phase resulting from the stacking of six [AO(3)] layers and one oxygen deficient [AO(3)] layer, thereby creating LiO4 tetrahedra in addition to the LiO6 octahedra and face-sharing Ru2O9 bi-octahedra formed from the [AO(3)] layers. The compound crystallizes in the space group R (3) over bar m with a = 5.7927(1)Angstrom and c = 50.336(2) Angstrom, Z = 3. Ba4NaRu3O12 crystallizes in the space group P6(3)mc with lattice parameters of a = 5.8014(2) Angstrom and c 19.2050(9) Angstrom, Z 2. BBa4NaRuO12 12 is identical to a previously reported neutron refinement structure. The magnetic properties of Ba7Li3RuO20 are also reported. (C) 2003 Elsevier Science (USA). All rights reserved.

Single crystals of Ca3.15Li0.85IrO6, Sr3LiIrO6, Ca3LiRuO6 and Sr3LiRuO6 were synthesized by high temperature flux growth. The compounds crystallize with trigonal (rhombohedral) symmetry in the space group R3̄c, Z=6: Ca3.15Li0.85IrO6 a=9.2686(3) Å, c=10.8755(5) Å; Sr3LiIrO6 a=9.6355(3) Å, c=11.1439(4) Å; Ca3LiRuO6 a=9.2330(3) Å, c=10.7441(4) Å; Sr3LiRuO6 a=9.6294(4) Å, c=11.0963(5) Å. All structures were determined by single crystal X-ray diffraction. The four oxides, A3LiMO6 (A=Ca, Sr; M=Ir, Ru), are isostructural with the K4CdCl6 structure type and contain infinite one-dimensional chains of alternating face-sharing MO6 octahedra and LiO6 trigonal prisms. These chains, in turn, are separated by infinite chains of alkaline–earth cations. The magnetic susceptibility of Ca3.15Li0.85IrO6 is consistent with that of a simple paramagnet.

Single crystals of a new Ba–Rh–Ir–O oxide were grown from a molten potassium carbonate flux. The new compound, Ba12Rh9.25Ir1.75O33, is structurally related to the 2H-hexagonal perovskite structure and contains pseudo one-dimensional chains of alternating units of ten face-sharing (Rh/Ir)O6 octahedra and one (Rh/Ir)O6 trigonal prism. The magnetic susceptibility of Ba12Rh9.25Ir1.75O33 is featureless, indicating the absence of magnetic order. The oxide is a semiconductor with a room temperature resistance of 280Ω.

Single crystals of two new osmium-containing triple perovskites, Ba(3)LiOs(2)O(9) and Ba(3)NaOs(2)O(9), were grown from reactive molten hydroxide fluxes in sealed silver tubes. They crystallize in the space group P6(3)/mmc with lattice parameters of a = 5.8025(1) A, c = 14.1468(4) A for Ba(3)LiOs(2)O(9) and a = 5.8858(1) A, c = 14.3451(5) A for Ba(3)NaOs(2)O(9). The magnetic susceptibility of these osmates indicates significant Os-Os coupling within the octahedra pair.

Two new mixed-valent triple perovskites, Ba3MRU2O9 (M = Li, Na), were grown from reactive hydroxide fluxes. They crystallize in the hexagonal space group P6(3)/mmc, where Ru(V) and Ru(VI) are disordered on only one crystallographic site. Upon cooling, single crystals of Ba3NaRU2O9 undergo a complex symmetry-breaking structural transition at ca. 225 K from room-temperature hexagonal symmetry to a low-temperature orthorhombic symmetry, space group Cmcm. Accompanying this structural transition is a rather abrupt decrease in the magnetic susceptibility at 210 K followed by a steady decrease in the susceptibility with decreasing temperature. Interestingly, the lithium analogue does not display any structural transition down to 100 K. The structural transition in Ba3NaRU2O9 generates three crystallographically unique Ru sites in the low-temperature structure as compared to only one distinct site in the room-temperature structure. On the basis of an analysis of the Ru-Ru distances in the face-sharing bi-octahedra, the structural transition also appears to involve charge ordering of Ru(V) and Ru(VI), causing all Ru(V) to occupy one set of bioctahedra and all Ru(VI) to occupy another set.

Single crystals of the isostructural compounds Ba4Ir3O10 and Ba4(Co0.4Ir0.6)Ir2O10 were grown from a molten potassium carbonate flux. The two compounds crystallize in the orthorhombic space group Cmca with lattice parameters of a=5.780(2), b=13.339(5) and c=13.216(5) Å for Ba4Ir3O10, and a=5.776(2), b=13.255(4) and c=13.110(4) Å for Ba4(Co0.4Ir0.6)Ir2O10. The structure consists of groups of three face-sharing octahedra, which in turn share vertices, forming an undulating two-dimensional sheet. The magnetic susceptibility plot for Ba4Ir3O10 is featureless with an experimentally determined magnetic moment of 2.79 BM corresponding well to the theoretical value for all Ir4+. Ba4(Co0.4Ir0.6)Ir2O10, on the other hand, exhibits very complex magnetic behavior with two magnetic transitions at 100 and 75 K, indicative of ferromagnetic and anti-ferromagnetic interactions, respectively.

Two new compounds, Sr3NiRhO6 and Sr3CuRhO6, belonging to a family of 2H-perovskite related materials, were synthesized in both a commensurate and an incommensurate form. The oxides were structurally characterized by powder X-ray Rietveld refinements and magnetic measurements. The commensurate structure of Sr3NiRhO6 is isostructural with the rhombohedral K4CdCl6 structure (space group R3c; Z=6; a=9.5951(1) Å, c=11.0621(2) Å) while the structure of Sr3CuRhO6 forms in a monoclinic distortion of the K4CdCl6 structure (space group C 2/c; Z=4; a=9.2226(2) Å, b=9.6882(2) Å, c=6.6926(2) Å, β=92.440(2)°). The structures of Sr3NiRhO6 and Sr3CuRhO6 contain chains of alternating face-sharing NiO6/CuO6 trigonal prisms and RhO6 octahedra. The magnetic susceptibility of Sr3NiRhO6 shows an abrupt drop at 30 K, suggesting antiferromagnetic correlations between the transition metal containing chains. Sr3CuRhO6 displays ferromagnetic-type ordering below 10 K. When the samples are heated for prolonged periods of time, a transition to an incommensurate structure takes place. Depending on the specific synthesis conditions, different incommensurate structures can be obtained. The fitted lattice parameters with space group R3m (cell 1) and P31c (cell 2) are a=9.6201(6) Å, c1=2.6732(2) Å, c2=3.9803(8) Å for Sr3NiRhO6+δ and a=9.624(2) Å, c1=2.6981(5) Å, c2= 3.9539(5) Å for Sr3CuRhO6+δ. The magnetic susceptibilities of the incommensurate compounds are quite different from their commensurate analogues, as all signs of long-range magnetic order disappear.

Single crystals of Ba2LiOsO6 and Ba2NaOsO6 were grown from molten hydroxide fluxes. The oxides form in the double perovskite structure and contain heptavalent osmium. The structures crystallize in space group Fm3̄m with lattice parameters of 8.1046(2) Å and 8.2870(3) Å for the lithium and sodium containing compounds, respectively. Magnetic susceptibility measurements show evidence of antiferromagnetic correlations below 8 K for Ba2LiOsO6 and ferromagnetic-like ordering below 8 K for Ba2NaOsO6. The measured magnetic moment is unusually small for both materials, μeff=0.733 BM and μeff=0.677 BM for the lithium and sodium containing compounds, respectively.

Single crystals of Ba8CoRh6O21, grown out of a potassium carbonate flux, were characterized by single-crystal X-ray diffraction and magnetic measurements. X-ray data were collected in a superspace group approach and solved using the JANA2000 software package. Ba8CoRh6O21 represents the first example of a structurally characterized m = 5, n = 3 member of the A3n+3mA'nB3m+nO9m+6n family of 2H hexagonal perovskite related oxides and contains chains consisting of six consecutive RhO6 octahedra followed by one distorted CoO6 trigonal prism. Magnetic measurements were carried out on large aligned single crystals, and a very large magnetic anisotropy in the magnetic susceptibility, persisting up to room temperature, was observed.

Recent advances in the synthesis, especially in the area of crystal growth, of a new family of oxides structurally related to the 2H-hexagonal perovskite are presented. This family of oxides, whose structures consist of chains of alternating octahedra and trigonal prisms along the c-direction, can be described by the general formula A3n+3mAn′B3m+nO9m+6n. An introduction to this structural description, which allows for a continuum of structures with an increasing ratio of octahedra to trigonal prisms, is given; in essence, this can lead to a never-ending group of structurally diverse members. Instrumental in the understanding of these structures has been the application of the superspace group formalism, which led to the successful determination of the structures of a growing number of these oxides, both commensurate and incommensurate; its usefulness to the structural characterization of these phases is discussed. The combination of the structural description, including the superspace group formalism, and the synthesis techniques have enabled this field to expand. Examples from nearly every section of the periodic table are provided to illustrate both synthetic challenges and the existence of different structural polytypes.

Single crystals of Ba9Rh8O24, grown from a molten potassium carbonate flux, crystallize in the spacegroup R3c with lattice parameters of a = 10.0899(4) and c = 41.462(2) A. Magnetic measurements on oriented single crystals reveal the existence of magnetic anisotropy.

Single crystals of Sr6Rh5O15 were grown from a molten potassium carbonate flux. The structure was solved by both the traditional 3-D crystallographic approach and the 4-D superspace group approach using JANA2000. Both methods produced an equivalent structure determination, thereby confirming the 4-D superspace group approach as an effective structure solution method for 3-D commensurate composite structures. Sr6Rh5O15 corresponds to the n = 1, m = 1 member of the A3n+3mA'nB3m+nO9m+6n family of 2H hexagonal perovskite-related oxides. This compound is characterized by pseudo-one-dimensional polyhedral chains of four face-sharing RhO6 octahedra followed by one RhO6 trigonal prism. These chains in turn are separated by [Sr](infinity) chains. Magnetic measurements were carried out on oriented single crystals, and a very large magnetic anisotropy in the magnetic susceptibility was observed.

Organometallic polymers were prepared by acyclic diyne metathesis (ADIMET) or by Pd-catalyzed coupling of 1,3-diethynylcyclobutadiene(cyclopentadienyl)cobalt with a suitably substituted diiodobenzene. The polymers obtained by Heck coupling show a degree of polymerization (Pn) of 20-60. The monomers for ADIMET were made by the Pd-catalyzed coupling of [1,3-bis(trimethylsilylethynyl)-2,4-bis(trimethylsilyl)cyclobutadiene](cyclopentadienyl)cobalt to 1-bromo-2,5-dialkyl-4-propynylbenzenes in the presence of KOH in yields of 40-48%. The monomers carry hexyl, ethylhexyl, and (S)-3,7-dimethyloctyl side chains. Polymerization of the propynylated monomers furnishes organometallic polymers with a Pn of up to 230 arylene-ethynylene units. The polymers were fully characterized by polarizing microscopy, transmission electron microscopy, circular dichroism, differential scanning calorimetry, and X-ray diffraction (XRD). They show nematic, lyotropic liquid crystalline phases as well as chiroptical properties from which aggregation in poor solvents and in the solid state can be concluded. Lamellar or irregular honeycomb-shaped morphologies in these organometallic polymers can be detected by electron microscopy.