Unexpected crystallization of the metastable tubular coordination polymer of cucurbit[6]uril with magnesium ions which spontaneously transforms into a discrete coordination complex

CrystEngComm ◽  
2014 ◽  
Vol 16 (18) ◽  
pp. 3699-3702 ◽  
Author(s):  
Oksana Danylyuk ◽  
Vladimir P. Fedin
Keyword(s):  
Coordination Polymer ◽  
Metastable Phase ◽  
Coordination Complex ◽  
Magnesium Ions ◽  
Kinetic Crystallization

We report on the kinetic crystallization of the tubular coordination polymer constructed from cucurbit[6]uril and magnesium ions. The metastable phase spontaneously converts into a thermodynamically favored discrete coordination complex.

Polymorphs of a copper coordination compound: interlinking active sites enhance the electrocatalytic activity of the coordination polymer compared to the coordination complex

CrystEngComm ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 425-429
Author(s):  
Pandi Muthukumar ◽  
Mehboobali Pannipara ◽  
Abdullah G. Al-Sehemi ◽  
Dohyun Moon ◽  
Savarimuthu Philip Anthony
Keyword(s):  
Coordination Polymer ◽  
Coordination Compound ◽  
Electrocatalytic Activity ◽  
Active Sites ◽  
Coordination Complex ◽  
Neutral Medium ◽  
Coordination Environment ◽  
Copper Coordination ◽  
Copper Coordination Polymer

A copper coordination polymer exhibits highly enhanced HER activity in neutral medium compared to a coordination complex with a similar coordination environment.

A hydrogen bonded Co(ii) coordination complex and a triply interpenetrating 3-D manganese(ii) coordination polymer from diaza crown ether with dibenzoate sidearms

CrystEngComm ◽  
2016 ◽  
Vol 18 (14) ◽  
pp. 2425-2436 ◽  
Author(s):  
Liang Liao ◽  
Conrad W. Ingram ◽  
John Bacsa ◽  
Z. John Zhang ◽  
Tandabany Dinadayalane
Keyword(s):  
Coordination Polymer ◽  
Crown Ether ◽  
Coordination Complex ◽  
Hydrogen Bonded

A water soluble calcium–sodium based coordination polymer: selective release of calcium at specific binding sites on proteins

RSC Advances ◽  
2014 ◽  
Vol 4 (46) ◽  
pp. 24038-24041 ◽  
Author(s):  
Ruchi Gaur ◽  
Ambadipudi Susmitha ◽  
K. V. R. Chary ◽  
Lallan Mishra
Keyword(s):  
Coordination Polymer ◽  
Single Crystal ◽  
Binding Sites ◽  
Specific Binding ◽  
Water Soluble ◽  
Coordination Complex ◽  
X Ray Diffraction ◽  
X Ray ◽  
Specific Binding Sites ◽  
Soluble Calcium

A calcium–sodium based water soluble coordination complex, [{Ca4Na(EGTA)2(H2O)13}n·NO3] (EGTA = ethylene bis(oxyethylenenitrilo)tetraaceticacid), has been synthesized hydrothermally and characterized using spectroscopic and single crystal X-ray diffraction techniques.

scholarly journals A 1-D coordination polymer route to catalytically active Co@C nanoparticles

RSC Advances ◽  
2016 ◽  
Vol 6 (45) ◽  
pp. 38533-38540 ◽  
Author(s):  
Anand Pariyar ◽  
Siddharth Gopalakrishnan ◽  
Joseph Stansbery ◽  
Rajankumar L. Patel ◽  
Xinhua Liang ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Coordination Complex ◽  
Benzenedicarboxylic Acid ◽  
Catalytically Active ◽  
Cobalt Nanoparticle ◽  
Nanoparticle Composites

Pyrolysis of a 1-D polymeric cobalt(ii) coordination complex ([Co(BDC)(Mim)2]n, H2BDC = benzenedicarboxylic acid; Mim = N-methylimidazole) results in the formation of carbon embedded fcc cobalt nanoparticle composites, Co@C.

scholarly journals Crystal engineering with copper and melamine

RSC Advances ◽  
2021 ◽  
Vol 11 (39) ◽  
pp. 23943-23947
Author(s):  
Ignacio Bernabé Vírseda ◽  
Shiraz Ahmed Siddiqui ◽  
Alexander Prado-Roller ◽  
Michael Eisterer ◽  
Hidetsugu Shiozawa
Keyword(s):  
Coordination Polymer ◽  
Crystal Engineering ◽  
Room Temperature ◽  
Coordination Complex ◽  
Structure Control ◽  
Size And Structure

Size and structure control of gem-like quality monocrystals – copper–melamine coordination complex, and copper–chlorine coordination polymer – is demonstrated at room temperature.

Observations of the Thermal Decomposition of Brucite

1968 ◽  
Vol 26 ◽  
pp. 446-447
Author(s):  
P. L. Burnett ◽  
W. R. Mitchell ◽  
C. L. Houck
Keyword(s):  
Thermal Decomposition ◽  
Magnesium Oxide ◽  
Basal Plane ◽  
Magnesium Ions ◽  
A Value ◽  
Reaction Proceeds

Natural Brucite (Mg(OH)2) decomposes on heating to form magnesium oxide (MgO) having its cubic ﹛110﹜ and ﹛111﹜ planes respectively parallel to the prism and basal planes of the hexagonal brucite lattice. Although the crystal-lographic relation between the parent brucite crystal and the resulting mag-nesium oxide crystallites is well known, the exact mechanism by which the reaction proceeds is still a matter of controversy. Goodman described the decomposition as an initial shrinkage in the brucite basal plane allowing magnesium ions to shift their original sites to the required magnesium oxide positions followed by a collapse of the planes along the original <0001> direction of the brucite crystal. He noted that the (110) diffraction spots of brucite immediately shifted to the positions required for the (220) reflections of magnesium oxide. Gordon observed separate diffraction spots for the (110) brucite and (220) magnesium oxide planes. The positions of the (110) and (100) brucite never changed but only diminished in intensity while the (220) planes of magnesium shifted from a value larger than the listed ASTM d spacing to the predicted value as the decomposition progressed.

TEM study of order, structure and defects of β and martensite in Cu-Al-Mn shape memory alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 188-189
Author(s):  
J.M. Guilemany ◽  
F. Peregrin
Keyword(s):  
Shape Memory ◽  
Orthophosphoric Acid ◽  
Isopropyl Alcohol ◽  
Metastable Phase ◽  
Characteristic Temperature ◽  
Ethanol Solution ◽  
Order Structure ◽  
Thin Foils ◽  
Polycrystalline Alloys ◽  
Diamond Saw

The shape memory effect (SME) shown by Cu-Al-Mn alloys stems from the thermoelastic martensitic transformation occuring between a β (L2,) metastable phase and a martensitic phase. The TEM study of both phases in single and polycrystalline Cu-Al-Mn alloys give us greater knowledge of the structure, order and defects.The alloys were obtained by vacuum melting of Cu, Al and Mn and single crystals were obtained from polycrystalline alloys using a modified Bridgman method. Four different alloys were used with (e/a) ranging from 1.41 to 1.46 . Two different heat treatments were used and the alloys also underwent thermal cycling throughout their characteristic temperature range -Ms, Mf, As, Af-. The specimens were cut using a low speed diamond saw and discs were mechanically thinned to 100 μm and then ion milled to perforation at 4 kV. Some thin foils were also prepared by twin-jet electropolishing, using a (1:10:50:50) urea: isopropyl alcohol: orthophosphoric acid: ethanol solution at 20°C. The foils were examinated on a TEM operated at 200 kV.

A Metastable Crystalline Phase Coexisted with the Decagonal Quasicrystals in Rapidly Solidified Al-Ir Al-Pd and Al-Pt Alloys

1990 ◽  
Vol 48 (1) ◽  
pp. 572-573
Author(s):  
Wang Rong ◽  
Ma Lina ◽  
K.H. Kuo
Keyword(s):  
Metastable Phase ◽  
Hexagonal Phase ◽  
Icosahedral Quasicrystal ◽  
Decagonal Quasicrystal ◽  
Decagonal Phase ◽  
Decagonal Quasicrystals ◽  
Pt Alloy ◽  
Pt Alloys ◽  
Diffraction Patterns ◽  
Rapidly Solidified

Up to now, decagonal quasicrystals have been found in the alloys of whole Al-Pt group metals [1,2]. The present paper is concerned with the TEM study of a hitherto unreported hexagonal phase in rapidly solidified Al-Ir, Al-Pd and Al-Pt alloys.The ribbons of Al5Ir, Al5Pd and Al5Pt were obtained by spun-quenching. Specimens cut from the ribbons were ion thinned and examined in a JEM 100CX electron microscope. In both rapidly solidified Al5Ir and Al5Pd alloys, the decagonal quasicrystal, with rosette or dendritic morphologies can be easily identified by its electron diffraction patterns(EDPs). The EDPs of the decagonal phase for the two alloys are quite similar. However, the existance of decagonal quasicrystal in the Al-Pt alloy has not been verified by our TEM study. It is probably for the reason that the cooling rate is not great enough for the Al5Pt alloy to form the decagonal phase. During the TEM study, a metastable hexagonal phase has been observed in the Al5Ir, Al5Pd and Al5Pt alloys. The lattic parameters calculated from the X-ray powder data of this phase are a=1.229 and c=2.647nm(Al-Pd) and a=1.231 and c=2.623nm(Al-Ir). The composition of this phase was determined by EDS analysis as Al4(Ir, Pd or Pt). It coexists with the decagonal phase in the alloys and transformed to other stable crystalline phases on heating to high temperature. A comparison between the EDPs of the hexagonal and the decagonal phase are shown in Fig.l. Fig. 1(a) is the EDPs of the decagonal phase in various orientions and the EDPs of the hexagonal phase are shown in Fig.1(b), in a similar arrangement as Fig.1(a). It can be clearly seen that the EDPs of the hexagonal phase, especially the distribution of strong spots, are quite similar to their partners of the decagonal quasicrystal in Fig.1(a). All the angles, shown in Fig.l, between two corresponding EDPs are very close to each other. All of these seem strongly to point out that a close structural relationshipexists between these two phases:[110]//d10 [001]//d2(D) //d2 (P)The structure of α-AlFeSi is well known [3] and the 54-atom Mackay icosahedron with double icosahedral shells in the α-AlFeSi structure [4] have been used to model the icosahedral quasicrystal structure. Fig.2(a) and (b) show, respectively, the [110] and [001] projections of the crystal structure of α- AlFeSi, and decagon-pentagons can easily be identified in the former and hexagons in the latter. In addition, the optical transforms of these projections show clearly decagons and hexagons of strong spots, quite similar to those in [110] and [001] EDPs in Fig.1(b). This not only proves the Al(Ir, Pt, Pd) metastable phase being icostructural with the α-AlFeSi phase but also explains the orientation relationship mentioned above.

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