scholarly journals Push–pull quinoidal porphyrins

2018 ◽  
Vol 16 (19) ◽  
pp. 3648-3654 ◽  
Author(s):  
Martin J. Smith ◽  
Iain M. Blake ◽  
William Clegg ◽  
Harry L. Anderson
Keyword(s):  
Crystal Structures ◽  
Significant Contribution ◽  
Layer Structures

Quinoidal porphyrins with electron-donating 1,3-dithiolane and electron-withdrawing dicyanomethylene groups form tightly π-stacked layer structures, despite their curved geometries and bulky aryl substituents. The crystal structures of these quinoidal porphyrins indicate that there is no significant contribution from singlet biradical or zwitterionic resonance forms.

Syntheses, crystal structures, and luminescent properties of three zinc carboxyphosphonates with 2D layered and 3D pillared-layer structures

2015 ◽  
Vol 429 ◽  
pp. 252-256 ◽  
Author(s):  
Hai-Qing Li ◽  
Peng Wang ◽  
Yun-Sheng Ma ◽  
Hong-Jian Cheng ◽  
Xiao-Yan Tang ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Luminescent Properties ◽  
Layer Structures

Crystal Structures of Seven Terephthaldiamide Derivatives

2002 ◽  
Vol 57 (8) ◽  
pp. 914-921 ◽  
Author(s):  
P. G. Jones ◽  
J. Ossowski ◽  
P. Kus
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
X Ray ◽  
Layer Structures ◽  
Structure Determinations ◽  
Independent Molecules

N,N′-Dibutyl-terephthaldiamide (1), N,N′-dihexyl-terephthaldiamide (2), N,N′-di(tert-butyl)- terephthaldiamide (3), N,N,N′,N′-tetrabutyl-terephthaldiamide (4), 1,1′-terephthaloylbis- pyrrolidine (5), 1,1′-terephthaloyl-bis-piperidine (6), and 4,4′-terephthaloyl-bis-morpholine (7) have been synthesised and physicochemically characterised. The X-ray structure determinations reveal imposed inversion symmetry for compounds 1-6; compound 3 has two independent molecules with inversion symmetry in the asymmetric unit. Compounds 1-3 form classical hydrogen bonds of the type N-H···O=C, leading to a ribbon-like arrangement of molecules (1 and 2) or a layer structure (3). Compound 3 also displays a very short C-H···O interaction, a type of hydrogen bond that is also observed in compounds 4-7, which lack classical donors; thereby compounds 4-6 form layer structures and 7 a complex threedimensional network.

scholarly journals Soft 2D Layer Porous Coordination Polymers with 1,2-Di(4-pyridyl)ethane

2013 ◽  
Vol 66 (4) ◽  
pp. 464 ◽  
Author(s):  
Keisuke Kishida ◽  
Satoshi Horike ◽  
Kanokwan Kongpatpanich ◽  
Susumu Kitagawa
Keyword(s):  
Coordination Polymer ◽  
Crystal Structures ◽  
Coordination Polymers ◽  
Adsorption Isotherms ◽  
Gas Adsorption ◽  
Porous Structures ◽  
Porous Coordination Polymers ◽  
Substituent Group ◽  
Layer Structures ◽  
Porous Coordination Polymer

Porous coordination polymer compounds consisting of Zn2+, 1,2-di(4-pyridyl)ethane, and dicarboxylates were synthesised and their crystal structures were determined. These are doubly interpenetrated 2D layer structures, and the flexibility of porous structures is dependent on the substituent group of the dicarboxylate. From gas adsorption studies, distinct adsorption isotherms were observed for CO2, CH4, C2H4, and C2H6 at 195 K and 273 K, respectively.

Single-layer structures of a100- and b010-Gallenene: a tight-binding approach

2019 ◽  
Vol 21 (28) ◽  
pp. 15798-15804 ◽  
Author(s):  
M. Nakhaee ◽  
M. Yagmurcukardes ◽  
S. A. Ketabi ◽  
F. M. Peeters
Keyword(s):  
Ab Initio ◽  
Linear Combination ◽  
Crystal Structures ◽  
Tight Binding ◽  
Single Layer ◽  
Atomic Orbitals ◽  
Layer Structures

Using the simplified linear combination of atomic orbitals (LCAO) method in combination with ab initio calculations, we construct a tight-binding (TB) model for two different crystal structures of monolayer gallium: a100- and b010-Gallenene.

Synthesis and Crystal Structures of New 1,3-Disubstituted Imidazoline-2-thiones

2013 ◽  
Vol 68 (11) ◽  
pp. 1239-1252 ◽  
Author(s):  
Gerhard Laus ◽  
Volker Kahlenberg ◽  
Klaus Wurst ◽  
Thomas Müller ◽  
Holger Kopacka ◽  
...  
Keyword(s):  
Bond Length ◽  
Crystal Structures ◽  
1H Nmr ◽  
Significant Contribution ◽  
Resonance Structure ◽  
X Ray Diffraction ◽  
Reference Compound ◽  
X Ray ◽  
Hydrolysis Of ◽  
By Products

Two methods (MeOH/K2CO3, pyridine/Et3N) were assessed for the introduction of sulfur into the 2-position of 1,3-disubstituted quaternary imidazolium salts 1-9 (Cl, I, BF4, PF6, CH3OSO3 were used as anions) to yield nine 1,3-disubstituted imidazoline-2-thiones 10-18 (1, 10: R1 = CH3, R2 = CH3; 2, 11: R1 = OCH2Ph, R2 = CH3; 3, 12: R1 = OCH3, R2 = CH3; 4, 13: R1 = OCH3, R2 = OCH3; 5, 14: R1 = NH2, R2 = CH2Ph; 6, 15: R1 = NCHPh, R2 = CH3; 7, 16: R1 = NH2, R2 = CH3; 8, 17: R1 = NCHPh, R2 = NCHPh; 9, 18: R1 = NH2, R2 = OCH3). Compounds 11-18 represent N-alkyloxy and N-amino imidazoline-2-thiones, whereas 10 served as reference compound. The first method was advantageous for the conversion 1 → 10 due to faster reaction, whereas in the reaction 2 → 11 considerable amounts of by-products were formed. Pure thiones 11, 14, 16, 17, and 18 were obtained only by the second method. Both methods worked for the synthesis of the methoxy derivatives 12 and 13 from 3 and 4, and the benzylideneamino derivative 15 from 6. 1-Amino-3- methylimidazoline-2-thione (16) was also prepared by hydrolysis of the benzylideneamino derivative 15. Crystal structures of seven 1,3-disubstituted imidazoline-2-thiones were determined by singlecrystal X-ray diffraction. Intermolecular C-H···S contacts were identified and, additionally, N-H···S interactions in aminothiones 14 and 16. The 1H NMR shifts of 10 and 13 were satisfactorily correlated with the Kamlet-Abboud-Taft π* and b parameters in ten solvents. From the lack of correlation with the a parameter and from the C=S bond length (average 1.68 Å ) a significant contribution of a mesoionic imidazolium-2-thiolate resonance structure seems unlikely.

In2.24(NCN)3 and NaIn(NCN)2: Synthesis and Crystal Structures of New Main Group Metal Cyanamides

1995 ◽  
Vol 50 (8) ◽  
pp. 1245-1251 ◽  
Author(s):  
Richard Dronskowski
Keyword(s):  
Crystal Structures ◽  
Structural Model ◽  
Point Group ◽  
Chemical Transport ◽  
Group Symmetry ◽  
Experimental Accuracy ◽  
X Ray ◽  
Main Group Metal ◽  
Layer Structures ◽  
Structure Determinations

Single crystals of In2.24(NCN)3 and NaIn(N CN)2 can be synthesized from a reaction between InBr and NaCN at 400 °C, followed by chemical transport at 400-500 °C. The X-ray crystal structure determinations of In2.24(NCN)3 (rhombohedral R3̄c, a = 606.09(4), c = 2884.4(2) pm, Z = 6) and NaIn(NCN)2 (orthorhombic Cmcm, a = 961.30(6), b = 716.84(5), c = 603.65(4) pm, Z = 4) reveal ionic layer structures built from sheets of cationic and anionic (cyanamide) motifs. While NaIn(NCN)2 contains In3+ and Na+ ions, In2.24(NCN)3 is a mixedvalence compound, incorporating a monovalent In+ ion besides trivalent indium. The NCN2- units of both In2.24(NCN)3 and NaIn(NCN)2 reflect perfect D∞h point group symmetry within the limits of experimental accuracy. Furthermore, an evaluation of all presently available crystallographic data on metal cyanamide crystal structures manifests that there is no evidence for a non-centrosymmetric description of any of these. Likewise, we propose an alternative centrosymmetric structural model for lead cyanamide, PbNCN, and question the evidence of the unsymmetrical, non-D∞h shaped cyanamide anion in the latter structure.

Syntheses and crystal structures of seven alicyclic diols which crystallise with layer structures instead of the helical tubuland inclusion lattice

1990 ◽  
pp. 855 ◽  
Author(s):  
Stephen C. Hawkins ◽  
Marcia L. Scudder ◽  
Donald C. Craig ◽  
A. David Rae ◽  
Razman B. Abdul Raof ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Layer Structures

Coordination Chemistry of Lipoic Acid and Related Compounds, Part 1 Syntheses and Crystal Structures of the UV- and Light-Sensitive Lipoato Complexes [M(lip)2(H2O)2] (M = Zn, Cd)

1997 ◽  
Vol 52 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Henry Strasdeit ◽  
Angelika von Döllen ◽  
Anne-Kathrin Duhme
Keyword(s):  
Coordination Chemistry ◽  
Crystal Structures ◽  
Metal Nitrate ◽  
X Ray Diffraction ◽  
Carboxylate Ligands ◽  
X Ray ◽  
Layer Structures ◽  
Network Of Hydrogen Bonds ◽  
Related Compounds ◽  
Nm Range

The rac-lipoato (lip-) complexes [Zn(lip)2(H2O)2] (1) and [Cd(lip)2(H2O)2] (2) were obtained in good yields from solutions of sodium lipoate and the respective metal nitrate in methanol/water. 1 and 2 form pale yellow, moderately light-sensitive crystals.Both compounds were structurally characterized by single-crystal X-ray diffraction. 1: C2/c, a = 39.958(6), b = 5.360(1), c = 10.794(1) Å, β = 95.76(1)°, Z = 4, wR2 = 0.150 (all data). 2: C2/c, a = 38.200(2), b = 5.472(1), c = 11.179(1) Å, β = 92.72(1)°, Z = 4, wR2 = 0.090 (all data). The metal ions are hexacoordinated by the oxygen atoms of two chelating carboxylate ligands and two aqua ligands. The crystal structures are very similar but not isotypic. They are layer structures, in which the complexes within a layer are interconnected by a network of hydrogen bonds. Adjacent layers have contacts via the 1,2-dithiolanyl rings of their lipoato ligands.Crystals of 1 and 2 decompose on exposure to visible light or ultraviolet radiation in the 280-390 nm range. Photopolymerization by formation of intermolecular S-S bonds is very probably involved. Furthermore, the infrared spectra reveal the transformation of COO- into COOH groups

Synthesis and Crystal Structures of New 1,4-Disubstituted 1,2,4-Triazoline-5-thiones

2014 ◽  
Vol 69 (9-10) ◽  
pp. 950-964 ◽  
Author(s):  
Gerhard Laus ◽  
Volker Kahlenberg ◽  
Klaus Wurst ◽  
Herwig Schottenberger
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Significant Contribution ◽  
Chemical Shifts ◽  
Resonance Structure ◽  
X Ray Diffraction ◽  
Reference Compound ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
H Nmr

AbstractIntroduction of sulfur into the 5-position of 1,4-disubstituted quaternary 1,2,4-triazolium salts (1-9; Cl, Br, I, BF4, PF6, CH3OSO3 were used as anions) by two methods was investigated. The syntheses of nine 1,4-disubstituted 1,2,4-triazoline-5-thiones 10-18 are reported (1, 10: R1 = CH3, R2 = CH3; 2, 11: R1 = NH2, R2 = CH3; 3, 12: R1 = NH2, R2 = CH(CH3)2; 4, 13: R1 = N(CH3)2, R2 = CH3; 5, 14: R1 = N(CH3)2, R2 = CH(CH3)2; 6, 15: R1 = CH3, R2 = NH2; 7, 16: R1 = OCH2Ph, R2 = CH3; 8, 17: R1 = OCH2Ph, R2 = CH2CH3; 9, 18: R1 = CH3, R2 = CH2Ph). Compounds 11-17 represent 1-amino, 4-amino, 4-dimethylamino, and 4-benzyloxy-1,2,4-triazoline-5- thiones, whereas 10 served as a reference compound. Thione 18 was identified as an unexpected by-product in the synthesis of 16 and was also prepared independently. Thermolysis of 10 in air gave 1,4-dimethyl-1,2,4-triazolium hydrogensulfate. Crystal structures of eight 1,4-disubstituted 1,2,4- triazoline-5-thiones were determined by single-crystal X-ray diffraction. Intermolecular hydrogen bonds (C-H···S, C-H···N, N-H···N, N-H···S) were observed in the solid state. The solvent-dependent 1H NMR chemical shifts of signals of 10 and 13 were satisfactorily correlated with the Kamlet- Abboud-Taft π* and b parameters in ten solvents. From the lack of correlation with the a parameter and from the C=S bond length (average 1.67 Å) a significant contribution of a mesoionic imidazolium-2-thiolate resonance structure seems unlikely

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