Temperature-Dependent Solid-state Luminescence and Reversible Phase Transition of (n-Bu4N)[Au(SC6H3-3,5-Me2)2]

2003 ◽  
Vol 32 (11) ◽  
pp. 1002-1003 ◽  
Author(s):  
Seiji Watase ◽  
Takayuki Kitamura ◽  
Nobuko Kanehisa ◽  
Masami Nakamoto ◽  
Yasushi Kai ◽  
...  
1987 ◽  
Vol 2 (1) ◽  
pp. 36-38 ◽  
Author(s):  
M. Auray ◽  
M. Quarton ◽  
P. Tarte

AbstractTwo molybdates MIV (MoO4)2 (with MIV = Hf or Zr) were synthesized by solid state reaction between MIVO2 and MoO3. Zirconium molybdate undergoes a reversible phase transition at 952 K.Hf(MoO4)2 and H.T. Zr(MoQ4)2, obtained as single crystals, are trigonal, space group with Z = 6; the cell dimensions are respectively a = 10.1005(3), c = 11.7230(5)Å; V = 1035.76(11)Å3; Dm(298 K) = 4.78(4), Dx = 4.792 Mg m−3 and a = 10.1409(3), c = 11.7097(5)Å; V = 1042.88(11)Å3; Dm (298 K) = 3.91(4), Dx = 3.926 Mg m−3.L.T. Zr(MoO4)2, indexed by the Visser automatic indexing program (1969) was found to be monoclinic, possible space group P2, P21 or Pm with Z = 4; the cell dimensions are a = 9.7557(5), b = 7.9373(5), c = 7.4631(4)Å, β = 97.959°(5); V = 572.3(5)Å Dm(298 K) = 4.74(5), Dx = 4.770 Mg m−3. Powder diffraction data were obtained at 293 K on a counter diffractometer with Ni-filtered copper radiation ( = 1.5418 Å).


2021 ◽  
Author(s):  
Yin-Qiang Zhang ◽  
Guan-Cheng Xu ◽  
Min Li

Solid-state phase transition materials have been received extraordinary interest due to their rich physical properties, such as the thermal, dielectric, and ferroelectric properties. Here, two In-based organic-inorganic hybrid compounds, (C6H5CH2CH2NH3)3[InBr5(H2O)]...


2017 ◽  
Vol 73 (8) ◽  
pp. 1255-1258
Author(s):  
Lipiao Bao ◽  
Marilyn M. Olmstead

The crystal structure determination based on 90 K data of the title imine ligand, C18H10ClNO, revealed non-merohedral twinning with three twin domains. In our experience, this is an indication of an ordering phase transition. Consequently, the structure was redetermined with higher temperature data, and a reversible phase transition was discovered. The higher temperature phase is indeed an ordered structure. At the higher temperature, the 4-chlorophenyl group has rotated by ca 7° into a crystallographic mirror plane. Warming the crystal from 90 K to 250 K changes the space group from triclinic P-1, to monoclinic P21/m. Diverse non-classical interactions are present in the crystal packing, and these are described for the phase change reported in this work. The crystal structure of the title imine ligand, measured at 100 K, has been reported on previously [Kovach et al. (2011). J. Mol. Struct. 992, 33–38].


2000 ◽  
Vol 78 (11) ◽  
pp. 1511-1518 ◽  
Author(s):  
Mikhail Yu Antipin ◽  
Ivan I Vorontsov ◽  
Irene I Dubovik ◽  
Vladimir Papkov ◽  
Francisco Cervantes-Lee ◽  
...  

We have reinvestigated the solid state structure of 1,1'-bis-(ferrocenyldimethylsilyl)ferrocenylene, (η5-FcSiMe2C5H4)2Fe, Fc = (η5-C5H5)Fe(η5-C5H4). Using a DSC technique we observed a reversible phase transition for this compound at 169(3)K with ΔH = 1.1 kJ/mol, and ΔS = 6.54 J/mol K. A single crystal X-ray diffraction study has demonstrated that this phase change involves a transformation from a high temperature phase, space group P21/c, Z = 2, to a triclinic low temperature phase, space group P[Formula: see text], Z = 4. The phase transition involves the loss of the molecular crystallographic center of symmetry and rotations about the terminal and central cyclopentadienyl ring pairs. The results are compared to those reported for ferrocene.Key words: solid state, phase transition, silyleneferrocenylene.


Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 472
Author(s):  
Miguel Cortijo ◽  
Ángela Valentín-Pérez ◽  
Mathieu Rouzières ◽  
Rodolphe Clérac ◽  
Patrick Rosa ◽  
...  

Octahedral tris(ethylenediamine) coordination complexes demonstrate helicoidal chirality, due to the arrangement of the ligands around the metal core. The enantiomers of the nitrate salts [Ni(en)3](NO3)2 and [Zn(en)3](NO3)2 spontaneously resolve to form a mixture of conglomerate crystals, which present a reversible phase transition from space group P6322 to enantiomorphic P6522 or P6122, with the latter depending on the handedness of the enantiomer. We report here the synthesis and characterization of [Mn(en)3](NO3)2 and [Co(en)3](NO3)2, which are isostructural to the Zn(II) and Ni(II) derivatives. The Mn(II) analogue undergoes the same phase transition centered at 150(2) K, as determined by single-crystal X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry. The Co(II) derivative does not demonstrate a phase transition down to 2 K, as evidenced by powder X-ray diffraction and heat capacity measurements. The phase transition does not impact the magnetic properties of the Ni(II) and Mn(II) analogues; these high spin compounds display Curie behavior that is consistent with S = 1 and 5/2, respectively, down to 20 K, while the temperature-dependent magnetic moment for the Co(II) compound reveals a significant orbital contribution.


2005 ◽  
Vol 61 (3) ◽  
pp. 321-328 ◽  
Author(s):  
Janet M. S. Skakle ◽  
John N. Low ◽  
James L. Wardell ◽  
Christopher Glidewell

The title compound, C18H17NO4, crystallizes from ethanol at ambient temperature as two concomitant polymorphs (I) and (II), both monoclinic P21/c with Z′ = 1. The less abundant form (I) undergoes a reversible phase-transition at ca 173 K to a third monoclinic polymorph (III), P21/n, with Z′ = 2, while the more abundant polymorph (II) is unchanged down to 120 K. In each polymorph of (I)–(III) the molecules are linked by pairs of O—H...O hydrogen bonds into cyclic dimers which are crystallographically centrosymmetric in (I) and (II), and approximately, but not crystallographically, centrosymmetric in (III). There are no direction-specific interactions between the hydrogen-bonded dimers in polymorph (I); in polymorph (II) the dimers are linked into sheets by C—H...N and C—H...π(arene) hydrogen bonds; in polymorph (III) the dimers are linked into chains by a C—H...π(arene) hydrogen bond. The interconversion of polymorphs (I) and (III) is a simple displacive phase transition.


2018 ◽  
Vol 28 (39) ◽  
pp. 1802003 ◽  
Author(s):  
Minguk Jo ◽  
Hyeon Jun Lee ◽  
Chadol Oh ◽  
Hyojin Yoon ◽  
Ji Young Jo ◽  
...  

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