I. V. Korolkov

Crystal Structure and Properties of Two Samarium Β-Diketonates

Samarium(III) tris-dipivaloylmethanate [Sm(dpm)3]2 (I) and sodium samarium(III) tetrakishexafluoroacetylacetonate [NaSm(hfa)4]n (II) are obtained. The crystal structures of I at 150(2) K (space group P21/n, a = 12.279(1) Å, b = 27.726(3) Å, с = 21.884(2) Å, β = 105.317(3)°, V = 7186.0(11) Å3, Z = 4) and II at 150(2) K (space group C2/c, a = 21.693(2) Å, b = 12.2068(7) Å, с = 14.402(1) Å, β = 124.731(3)°, V = 3134.2(4) Å3, Z = 4) are determined. The structure of the complex I is similar to that of the previously known dimeric [Ln(dpm)3]2 (Ln = La, Pr, Nd, Eu, Gd, Tb) complexes; and the structure of the complex II is similar to that of the known [NaLn(hfa)4]n (Ln = Y, Eu, Er) complexes. It is shown by thermogravimetry that the volatility of REE tris-dipivaloylmethanates increases from Lu to La, the volatility of REE sodium tetrakis-hexafluoroacetylacetonates increases from La to Lu.

New volatile zirconium(IV) complex with methoxy substituted β-diketonate

A new zirconium(VI) complex with fluorinated methoxy substituted β-diketonate ZrL4 is synthesized where L = 1,1,1-trifluoro-5-methoxy-5-methylhexane-2,4-dionate. The complex sublimates without decomposition at a low pressure (10–2 Torr) at 140 °C. The crystal structure of the complex is molecular and composed of mononuclear ZrL4 molecules. Crystallographic data for C32H40F12O12Zr are: C2/c, a = 12.193(2) Å, b = 21.922(4) Å, c = 15.585(3) Å, β = 101.51(3)°, V = 4082.1(14) Å3, Z = 4, d = 1.523 g/cm3. The coordination environment of the zirconium atom is formed by eight oxygen atoms of four β-diketonate ligands; the coordination polymer is a square antriprism. The Zr–O distances are in the range 2.16-2.19 Å. The thermal properties of the complex are studied by TG–DTA.

Crystal structure of [Pb3(OH)4Co(NO2)3](NO3)(NO2)·2H2O

The structure of [Pb3(OH)4Co(NO2)3](NO3)(NO2)·2H2O is determined by single crystal X-ray diffraction. The crystallographic characteristics are as follows: a = 8.9414(4) Å, b = 14.5330(5) Å, c = 24.9383(9) Å, V = 3240.6(2) Å3, space group Pbca, Z = 8. The Co(III) atoms have a slightly distorted octahedral coordination formed by three nitrogen atoms belonging to nitro groups (Co–Nav is 1.91 Å) and three oxygen atoms belonging to hydroxyl groups (Co–Oav is 1.93 Å). The hydroxyl groups act as μ3-bridges between the metal atoms. The geometric characteristics are analyzed and the packing motif is determined.

New praseodymium polyselenide PrSe1.95: Synthesis and X-ray diffraction study of crystals

By thermodynamic simulation of the Pr–Se–I system, the optimal growth conditions for new crystalline praseodymium polyselenide PrSe1.95, whose existence was proved in our previous works, are determined. Based on the obtained information, the PrSe1.95 crystals are grown by the vapor transport technique using iodine as the transport agent. The crystals produced are identified by microprobe and powder X-ray diffraction analysis. Single crystal X-ray diffraction shows that the crystals are not monophasic, but consist of blocks with tetragonal and monoclinic symmetries, which have a common structural prototype (PbFCl). For two different crystals cut out of a larger one, the structure is determined and the composition is refined. The results of powder and single crystal X-ray diffraction analyses of one of these crystals (monoclinic one) coincide.

Crystal Structures of [Dy(dpm)3]2 and Dy(dpm)3, Luminescent and X-Ray Fluorescent Study of Lanthanide(III) Tris-Dipivaloylmethanates

Crystal structures of [Dy(dpm)3]2 (1) at 155(2) K (space group P21/n, a = 12.2191(3) Å, b = 27.6044(6) Å, с = 21.8615(5) Å, β = 105.172(1)°, V = 7116.9(3) Å3, Z = 4) and Dy(dpm)3 (2) at 200(2) K (space group Pmn21, a = 17.8741(7) Å, b = 10.5639(4) Å, с = 9.8336(4) Å, V = 1856.78(13) Å3, Z = 2) are determined. The structure of complex 1 is similar to the previously known dimeric packings [Ln(dpm)3]2 (Ln = La, Pr, Nd, Eu, Gd, Tb). Complex 2 is isostructural to the previously studied molecular complexes Er(dpm)3 and Lu(dpm)3. At room temperature the luminescence quantum yield (QY) of Tb(dpm)3 is found to reach 77% and that of Dy(dpm)3 is 5%, while for the other Lu(dpm)3 complexes, where Ln = Pr, Nd, Sm, Eu, Gd, Ho, Er, Tm, Yb, QY is below 1%. A series of [Tb(dpm)3]2 and Dy(dpm)3 solid solutions is obtained by evaporating mixtures from solutions. Molecular films of these complexes on Si, Cu, Ni, Ti, KBr substrates are obtained by vacuum deposition.

Crystal Structure and Properties of [Rh 2 (H 2 O) 8 (μ-OH) 2 ](NO 3 ) 4 ·4H 2 O

A procedure to synthesize (μ-hydroxo)bis-pentaaquarhodium(III) nitrate tetrahydrate [Rh2(H2O)8(μ-OH)2](NO3)4·4H2O from potassium hexachlororhodiate(III) is elaborated. The compound is isolated into the solid phase and structurally characterized. The crystallographic data are as follows: a = 5.8763(2) Å, b = 9.4749(4) Å, c = 9.6249(3) Å, α = 79.905(1)°, β = 84.324(1)°, γ = 82.922(1)°, space group P-1, Z = 1, ρcalc = 2.240 g/cm3. The compound is soluble in water, ethanol, and acetone. Hydrolysis takes place in concentrated nitric acid with the formation of mononuclear aqua- and aquanitrate complexes. Thermal decomposition of the salt at a temperature above 580 °C leads to the formation of a single product–rhodium(III) oxide.

Synthesis of ZnO nanoparticles and a composite with polyacrylamide in acrylamide solutions

The use of solutions of acrylamide (AAm) opens up new ways for easy one-step synthesis of ZnO nanoparticles (NPs) and their composites with polyacrylamide (PAAm). To obtain a nanocrystalline product in which the composition of NPs is close to {(ZnO)m(Zn2+)n}(CH3COO−)2n with n/m = 0.292, the hydrolysis of Zn(CH3COO)2·2H2O should be carried out in 96% ethanol. In this process, AAm plays the role of an organic base that accepts protons and does not act as a protective ligand. The ZnO NPs/PAAm composite is formed as a viscous transparent colorless hydrogel if the same reaction is carried out in an aqueous medium simultaneously with the radical polymerization of AAm initiated by (NH4)2S2O8. A solid composite can be isolated due to the destruction of the hydrogel by the addition of ethanol. In the composite, PAAm acts as a polymeric matrix in which ZnO NPs are distributed. The synthesis products were characterized by XRD, TEM, SEM, EDX, DLS, IR, Raman scattering, photoluminescence, and chemical analysis. The particles in both products were nanocrystals of hexagonal ZnO about a few nanometers in size. The powder of {(ZnO)m(Zn2+)n}(CH3COO−)2n NPs had a yellow photoluminescence with emission maximum at λem = 590 nm. The photoluminescence band of the ZnO NPs/PAAm hydrogel had a maximum at λem = 449 nm.Graphical abstract

Volatile zirconium complexes with sterically hindered β-diketonates: Structure and thermal properties

The structure and thermal properties of a novel zirconium(IV) complex with a methoxy substituted β-diketonate ligand tetrakis-(2-methoxy-2,6,6-trimethylheptane-3,5-dionato)zirconium are described. The complex sublimes without decomposition under low pressure (10–2 Torr) at 200 °C. The crystal structure of the complex is molecular and is composed of two structural Zr(zis)4 isomers in a 1:1 ratio. The crystallographic data are as follows: C88H152F24O24Zr2, P-1, a = 12.1350(7) Å, b = 19.7733(10) Å, c = 21.0526(12) Å, α = 83.338(2)°, β = 89.571(2)°, γ = 73.515(2)°, V = 4809.5(5) Å3, Z = 2, d = 1.227 g/cm3. The coordination environment of the zirconium atom consists of eight oxygen atoms from four β-diketonate ligands; the coordination polyhedron is a square antiprism. The Zr–O distances are in a range 2.127-2.202 Å. The thermal properties of the complex are studied by TG–DTA. The effect of the crystal structure (molecular packing) on the volatility and thermal properties is compared for the new complex and two other analogous zirconium complexes with β-diketonate ligands containing bulky terminal substituents. The results of the mass spectrometric study of thermal behavior of the complexes on programmed heating of vapor under the conditions similar to those in a hot wall CVD reactor under low pressure, including the decomposition in the presence of oxygen, are discussed.

Structure and thermal properties of heterometallic complexes for chemical vapor deposition of Cu–Pd films

Novel volatile heterocomplex compounds based on copper(II) and palladium(II) fluorinated β-diketonates are studied. The crystals of the synthesized compounds are shown to be composed of 1D coordination polymers in the form of chains of alternating molecules of monometallic complexes. The crystallographic data for [Cu(hfa)2∙Pd(zif)2] are as follows: C26H22F18O10CuPd, P21/c, a = 7.9947(18) Å, b = 19.277(4) Å, c = 13.609(3) Å, β = 118.298(15)°, V = 1846.7(7) Å3, Z = 2, d = 1.810 g/cm3. The thermal properties of the compounds are examined by TG-DTA and vacuum sublimation. The complexes are studied as the precursors for producing copper-palladium alloy films by chemical vapor deposition. It is demonstrated that bimetallic alloy coatings with a ratio Cu/Pd = 1:1 can be prepared from [Cu(hfa)2∙Pd(zif)2].

Crystal structure of [Pb 3 (OH) 4 Co(NO 2 ) 3 ](NO 3 )(NO 2 )·2H 2 O

The structure of [Pb3(OH)4Co(NO2)3](NO3)(NO2)·2H2O is determined by single crystal X-ray diffraction. The crystallographic characteristics are as follows: a = 8.9414(4) Å, b = 14.5330(5) Å, c = 24.9383(9) Å, V = 3240.6(2) Å3, space group Pbca, Z = 8. The Co(III) atoms have a slightly distorted octahedral coordination formed by three nitrogen atoms belonging to nitro groups (Co–Nav is 1.91 Å) and three oxygen atoms belonging to hydroxyl groups (Co–Oav is 1.93 Å). The hydroxyl groups act as μ3-bridges between the metal atoms. The geometric characteristics are analyzed and the packing motif is determined.