Tris-triphenylsiloxy compounds of aluminium

1992 ◽  
Vol 70 (3) ◽  
pp. 771-778 ◽  
Author(s):  
Allen W. Apblett ◽  
Alison C. Warren ◽  
Andrew R. Barron
Keyword(s):  
Variable Temperature ◽  
Molecular Structures ◽  
Water Ligand ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Phenyl Rings ◽  
Coordinated Water ◽  
Hydrolysis Of ◽  
Solvent Complex

The reaction of AlMe3 with three equivalents of HOSiPh3 in THF results in the formation of the solvent complex Al(OSiPh3)3(THF) (1). Hydrolysis of 1 yields the stable water complex Al(OSiPh3)3(H2O)(THF)2 (2) in which the THF molecules are hydrogen bonded to the coordinated water ligand. Compounds 1 and 2 have been fully characterized by 1H, 13C, 17O, 27Al, and 29Si NMR and IR spectroscopy. In addition, variable temperature 1H NMR of 2 has been employed to investigate the steric interactions between the phenyl rings of adjacent siloxide ligands. The molecular structures of the solvates 1•(THF) and 2•(THF)1.25 have been determined by X-ray crystallography. 1•(THF): monoclinic P21/c, a = 10.03 (1), b = 23.758 (6), c = 23.294 (7) Å, β = 101.13 (6)°, Z = 4, R = 0.084, Rw = 0.094. 2•(THF)1.25: cubic [Formula: see text], a = 23.034 (3) Å, Z = 4, R = 0.093, Rw = 0.099. Keywords: aluminium, siloxide, hydrolysis, complex, NMR spectroscopy.

Dynamic stereoisomerization in inherently chiral bimetallic [2]catenanes

2015 ◽  
Vol 51 (27) ◽  
pp. 5840-5843 ◽  
Author(s):  
Thirumurugan Prakasam ◽  
Matteo Lusi ◽  
Elisa Nauha ◽  
John-Carl Olsen ◽  
Mohamadou Sy ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Variable Temperature ◽  
Redox Processes ◽  
Metal Translocation ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Inherently Chiral

Stereoisomerization and the unprecedented phenomenon of metal translocation in the absence of redox processes were probed in two inherently chiral bimetallic [2]catenanes by using a combination of variable-temperature 1H NMR and CD spectroscopies, X-ray crystallography, and DFT calculations.

scholarly journals Cavity-Containing [Fe2L3]4+ Helicates: An Examination of Host-Guest Chemistry and Cytotoxicity

2021 ◽  
Vol 9 ◽  
Author(s):  
Lynn S. Lisboa ◽  
Mie Riisom ◽  
Roan A. S. Vasdev ◽  
Stephen M. F. Jamieson ◽  
L. James Wright ◽  
...  
Keyword(s):  
Cell Lines ◽  
Molecular Structures ◽  
Ionization Mass ◽  
Antiproliferative Effects ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Drug Molecules ◽  
Guest Chemistry

Two new di(2,2′-bipyridine) ligands, 2,6-bis([2,2′-bipyridin]-5-ylethynyl)pyridine (L1) and bis(4-([2,2′-bipyridin]-5-ylethynyl)phenyl)methane (L2) were synthesized and used to generate two metallosupramolecular [Fe2(L)3](BF4)4 cylinders. The ligands and cylinders were characterized using elemental analysis, electrospray ionization mass spectrometry, UV-vis, 1H-, 13C and DOSY nuclear magnetic resonance (NMR) spectroscopies. The molecular structures of the [Fe2(L)3](BF4)4 cylinders were confirmed using X-ray crystallography. Both the [Fe2(L1)3](BF4)4 and [Fe2(L2)3](BF4)4 complexes crystallized as racemic (rac) mixtures of the ΔΔ (P) and ΛΛ (M) helicates. However, 1H NMR spectra showed that in solution the larger [Fe2(L2)3](BF4)4 was a mixture of the rac-ΔΔ/ΛΛ and meso-ΔΛ isomers. The host-guest chemistry of the helicates, which both feature a central cavity, was examined with several small drug molecules. However, none of the potential guests were found to bind within the helicates. In vitro cytotoxicity assays demonstrated that both helicates were active against four cancer cell lines. The smaller [Fe2(L1)3](BF4)4 system displayed low μM activity against the HCT116 (IC50 = 7.1 ± 0.5 μM) and NCI-H460 (IC50 = 4.9 ± 0.4 μM) cancer cells. While the antiproliferative effects against all the cell lines examined were less than the well-known anticancer drug cisplatin, their modes of action would be expected to be very different.

Halogenation of Tris(amido)tantalacarboranes with Dihalomethanes CH2X2 (X = Cl, Br)

2002 ◽  
Vol 67 (6) ◽  
pp. 791-807 ◽  
Author(s):  
Mark A. Fox ◽  
Andrés E. Goeta ◽  
Andrew K. Hughes ◽  
John M. Malget ◽  
Ken Wade
Keyword(s):  
Single Crystal ◽  
Prolonged Exposure ◽  
Chemical Shifts ◽  
Amide Group ◽  
The Other ◽  
X Ray ◽  
Nmr Chemical Shifts ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Hydrolysis Of

Slow reactions of isomeric metallacarboranes of general formulae [(NMe2)3TaC2B9H11] (3 isomers) and [(NMe2)3TaC2B9H10Me] (3 isomers) with CD2Cl2 afford quantitative yields of monochloro complexes [Cl(NMe2)2TaC2B9H11] and [Cl(NMe2)2TaC2B9H10Me]. Exposure to CD2Cl2 for months leads to solutions containing about 70% of the dichlorides in three cases. More prolonged exposure of these and the other monochlorides leads to a mixture of boron-substituted complexes. Hydrolysis of [3,3,3-(NMe2)3-3,1,2-TaC2B9H11] by moist toluene results in the formation of the oxo-bridged complex 3,3'-[3,3-(NMe2)2-3,1,2-TaC2B9H11]2(μ-O), characterised by single-crystal X-ray crystallography. The limited solubility of the latter complex in CD2Cl2 eliminates the presence of this compound in the reaction of [3,3,3-(NMe2)3-3,1,2-TaC2B9H11] with CD2Cl2. The reaction of [2,2,2-(NMe2)3-2,1,12-TaC2B9H11] with CH2Br2 in C6D6 quantitatively yields the monobromide [2-Br-2,2-(NMe2)2-2,1,12-TaC2B9H11]. Prolonged reaction with CH2Br2 leads directly to isomeric boron-substituted complexes with no evidence for dibromides. The influence on 11B, 13C and 1H NMR chemical shifts of replacing an amide group in [(NMe2)3TaC2B9H11] with chloride to give [Cl(NMe2)2TaC2B9H11] is also discussed.

scholarly journals [3.3]Dithia-bridged cyclophanes featuring a thienothiophene ring: synthesis, structures and conformational analysis

2009 ◽  
Vol 5 ◽  
Author(s):  
Sabir H Mashraqui ◽  
Yogesh Sanghvikar ◽  
Shailesh Ghadhigaonkar ◽  
Sukeerthi Kumar ◽  
Auke Meetsma ◽  
...  
Keyword(s):  
Conformational Analysis ◽  
Energy Minimization ◽  
Elevated Temperatures ◽  
Variable Temperature ◽  
Energy Difference ◽  
Nmr Analysis ◽  
Stable Conformation ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr

The synthesis of [3.3]dithia-bridged cyclophanes 7, 9 and 11 incorporating a fused heterocycle, thieno[2,3-b]thiophene is described. The structures are established by 1H NMR analysis and, in the case of 11, also by single crystal X-ray crystallography. Conformational analysis by variable temperature NMR suggests that cyclophanes 7, 9 and 11 exhibit conformationally rigid bridges and rings at least up to 130 °C. Energy minimization of 11 revealed anti -11 to be the most stable conformation. Although, the computed energy difference between the most stable conformation anti -11 and the next higher energy conformation syn-anti -11 is only 2.98 kJ/mol, it is intriguing that 11 does not exhibit thia-bridge inversion even at elevated temperatures.

Synthesis and characterization of [MII(bqb)] (M = Co, Ni, Cu), [N(n-Bu)4][CoIII(bqb)(CN)2], and [N(n-Bu)4][CoIII(bqb)(N3)2] containing deprotonated N,N'-bis(2-quinolinecarboxamide)-1,2-benzene (bqb) – X-ray crystal structures of [NiII(bqb)] and [N(n-Bu)4][CoIII(bqb)(N3)2]

2006 ◽  
Vol 84 (7) ◽  
pp. 971-978 ◽  
Author(s):  
Soria Meghdadi ◽  
Mehdi Amirnasr ◽  
Vratislav Langer ◽  
Alison Zamanpoor
Keyword(s):  
Crystal Structures ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Square Planar ◽  
Distorted Octahedral ◽  
Elemental Analyses

Cobalt(II), nickel(II), copper(II), and two cobalt(III) complexes of a new dianionic ligand, bqb, [H2bqb = N,N'-bis(2-quinolinecarboxamide)-1,2-benzene] have been synthesized and characterized by elemental analyses, IR, and 1H NMR spectroscopy. The crystal and molecular structures of the [Ni(bqb)] (2) and [N(n-Bu)4][CoIII(bqb)(N3)2] (5) complexes were determined by X-ray crystallography. Complex 2 crystallizes in the monoclinic space group C2/c with a distorted square-planar structure including two short Ni–N (1.848 Å) and two long Ni–N (1.958 Å) bonds. The structure consists of sheets formed in the plane parallel to the b axis and diagonal to vectors a and c by intermolecular hydrogen bonds. Complex 5 crystallizes in the monoclinic space group C2 with a distorted octahedral structure. The [N(n-Bu)4]+ ion is disordered at the C3A and C4A atoms of one Bu. The IR and 1H NMR spectra of the complexes are also discussed.Key words: N4-dianionic amido ligand (bqb), (bqb) complexes of Co(II), Ni(II), Cu(II), and Co(III), azide, cyanide, X-ray crystal structures.

A Structural Study on Indium Tris-thiocarbamates

1994 ◽  
Vol 49 (2) ◽  
pp. 193-198 ◽  
Author(s):  
S. Bhattacharya ◽  
Miss Neena Seth ◽  
V. D. Gupta ◽  
H. Nöth ◽  
M. Thomann
Keyword(s):  
Structural Study ◽  
Nmr Spectra ◽  
Variable Temperature ◽  
Point Group ◽  
Molecular Structures ◽  
X Ray ◽  
H Nmr ◽  
Group D

Indium tris(thiocarbamates) In(S2CNiPr2)3 (1), In(SOCNiPr2)3 (2) and In(S2CNC4H4)3 (3) have been synthesized and characterized. Variable temperature 1H NMR spectra of 1 and 2 are reported. The X-ray molecular structures of 1 and 3 are found to be quite similar; the symmetry of the In(S2C)3 unit in 3 is close to point group D3 with small asymmetry in the In-S bonds.

Synthesis, characterization, and single crystal X-ray structures of [CoIII(acacen)(thioacetamide)2]ClO4 and [CoIII((BA)2en)(thioacetamide)2]PF6 — Solvatochromic properties of [CoIII(acacen)(thioacetamide)2]ClO4

2005 ◽  
Vol 83 (12) ◽  
pp. 2073-2081 ◽  
Author(s):  
Mehdi Amirnasr ◽  
Vratislav Langer ◽  
Nahid Rasouli ◽  
Mehdi Salehi ◽  
Soraia Meghdadi
Keyword(s):  
Solid State ◽  
Molecular Structures ◽  
Axial Position ◽  
Monoclinic Space Group ◽  
Solid State Method ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Ligand Charge Transfer ◽  
Wavelength Absorption

The trans-[CoIII(acacen)(ta)2]ClO4 (1) and trans-[CoIII((BA)2en)(ta)2]PF6 (2) complexes, where H2acacen = bis(acetylacetone)ethylenediimine, H2(BA)2en = bis(benzoylacetone)ethylenediimine, and ta = thioacetamide, have been synthesized by a solid-state method, and characterized by elemental analyses, IR, UV–vis, and 1H NMR spectroscopy. The crystal and molecular structures of 1 and 2 were determined by X-ray crystallography. Both compounds crystallize in the monoclinic space group P2/n. The ClO4 and PF6 ions are both disordered, ClO4 on a twofold axis in 1 and PF6 on an inversion center in 2. Also bridging N-CH2-CH2-N is disordered in both compounds. The octahedral coordination of Co(III) is slightly distorted in both cases. The thioacetamide ligands are S-bonded and occupy the axial position. The IR, UV–vis, and 1H NMR spectra of the two complexes and their solvatochromic properties are also discussed. The longest wavelength absorption that appears at 517 nm for 1 and at 528 nm for 2 in chloroform is solvent dependent, and is assigned as a metal-mediated ligand-to-ligand charge transfer (LLCT).Key words: solid-state synthesis, thioactamide, Co(III) (Schiff base), crystal structure, solvatochromism, metal-mediated LLCT.

Hydrolysis and condensation of chlorophosphine and alkyl phosphite ligands on platinum and palladium. 31P and 195Pt nuclear magnetic resonance studies and the crystal and molecular structures of [Pt2Cl4{μ-(EtO)2POP(OEt)2}2] and [Cl2Pt{μ-(P(OEt)2O)2P(O)}PtCl(PEt3)2]

1986 ◽  
Vol 64 (2) ◽  
pp. 343-352 ◽  
Author(s):  
David Eric Berry ◽  
Kathryn Anne Beveridge ◽  
Gordon William Bushnell ◽  
Keith Roger Dixon ◽  
Alan Pidcock
Keyword(s):  
Spin Systems ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
H Nmr ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
Alkyl Phosphite

Hydrolysis of cis-[PtCl2-{P(OEt)2Cl}2] results in condensation of the phosphite to form [Pt2Cl4{μ-(EtO)2POP(OEt)2}2], which crystallizes in the monoclinic space group P21/n, with a = 13.814(7), b = 11.429(4), c = 10.726(5) Å, β = 106.30(5)°. Reactions of P(OEt)2Cl or (EtO)2POP(OEt)2 with [Pt2Cl4(PEt3)2] also yield very easily hydrolyzed products but in these cases an even more complex condensation occurs to yield [Cl2Pt{(μ-(P(OEt)2O)2P(O)}PtCl(PEt3)2], which crystallizes in the monoclinic space group P21/c, a = 17.547(8), b = 19.775(6), c = 11.268(3) Å, β = 106.42(3)°. Complete X-ray diffraction studies are reported for both crystals, confirming the presence of double (EtO)2POP(OEt)2 bridges in [Pt2Cl4{(μ-(EtO)2POP(OEt)2}2] and a novel triphosphite bridge in [Cl2Pt{μ-(P(OEt)2O)2P(O)}PtCl(PEt3)2]. Detailed analyses and computer simulation of the 31P{1H} and 195Pt{1H} nmr spectra of these complexes are also described, together with studies of the related compounds, [Pt2Me4{μ-(EtO)2POP(OEt)2}2] and [Cl2(Et3P)Pt{μ-(EtO)2POP(OEt)2}PtCl2(PEt3)]. In conjunction with previous studies of [Pt2Cl2(dppm)2] and related complexes, these spectra provide examples of several types of AA′XX′ spin systems and the analysis of these systems is discussed in detail.

Synthesis, characterization, and reactivity of the first hafnium alkyl complex stabilized by amidate ligands

2005 ◽  
Vol 83 (6-7) ◽  
pp. 1037-1042 ◽  
Author(s):  
Robert K Thomson ◽  
Brian O Patrick ◽  
Laurel L Schafer
Keyword(s):  
Coordination Chemistry ◽  
Solid State ◽  
Key Words ◽  
Low Temperatures ◽  
Variable Temperature ◽  
X Ray ◽  
X Ray Crystallography ◽  
Exchange Processes ◽  
Hydrolysis Of

A photo and thermally stable bis(amidate)–dibenzyl complex of Hf ([DMP(NO)Ph]2Hf(CH2Ph)2(THF) (2a) was formed as a monosolvated THF adduct in near quantitative yield from Hf(CH2Ph)4 and N-2,6-dimethylphenyl(phenyl)amide (1). Isomerization between the THF-bound product and the THF-free product can be observed visually by the conversion from a red-orange product at low temperatures to a pale yellow product at high temperatures. Solid-state crystallographic characterization of the orange product confirmed its constitution as a monosolvated species. Kinetic parameters for the exchange of the THF moiety were determined from variable-temperature NMR experiments. The product of the hydrolysis of the Hf dibenzyl species by water was characterized by X-ray crystallography, and was found to be a rare tetrametallic Hf oxo cluster species (3).Key words: hafnium, protonolysis, amidate, coordination chemistry, organometallic chemistry, exchange processes.

Synthesis, characterization, and the molecular structures of two new kinds of stilbene

2006 ◽  
Vol 84 (6) ◽  
pp. 867-873 ◽  
Author(s):  
Yan-Hong Liu ◽  
Tong-Lai Zhang ◽  
Jian-Guo Zhang ◽  
Li Yang ◽  
Jin-Yu Guo ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Thermal Decomposition ◽  
High Heat ◽  
Molecular Structures ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Decomposition Processes ◽  
Ft Ir ◽  
C Nmr

We report in this study the synthesis, crystal culture, and single-crystal X-ray crystallography of two new kinds of double stilbene, which were readily prepared from trinitro-p-xylene and p-tolualdehyde in the presence of piperidine. We found that these triclinic crystals belong to the space group P-1. These compounds were also investigated using FT-IR, 1H NMR, 13C NMR, and MS spectroscopy techniques. The thermal decomposition processes of the compounds were tested by DSC and TG-DTG at a heating rate of 10  C/min. These results indicate that the compounds have high heat-resistant stability.Key words: polynitrostilbene, molecular structure, thermal decomposition.

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