Hexaethylbenzene complexes of ruthenium and manganese — X-ray crystal structures and NMR spectra of [(HEB)2Ru2(µ-Cl)3][C5(CO2Me)5], [(HEB)Ru(H2O)3][BF4]2, (HEB)RuCl2[P(OMe)3], trans-RuCl2(PMe3)4, and (HEB)Mn(CO)2Br

2006 ◽  
Vol 84 (2) ◽  
pp. 277-287 ◽  
Author(s):  
Hari K Gupta ◽  
Philippa E Lock ◽  
Nada Reginato ◽  
James F Britten ◽  
Michael J McGlinchey

Hexaethylbenzene (HEB) and [(p-cymene)RuCl2]2 react in the melt to yield [(HEB)RuCl2]2 (6), the NMR spectra of which reveal the presence of [(HEB)2Ru2(µ-Cl)3]Cl in solution. In [(HEB)2Ru2(µ-Cl)3][C5(CO2Me)5] (7), the cation has D3h symmetry with alternating proximal and distal ethyl groups. Bridge cleavage of 6 with trimethyl phosphite or with trimethylphosphine gives (HEB)RuCl2[P(OMe)3] (9) or (HEB)RuCl2(PMe3) (10), respectively. The latter reaction also yields RuCl2(Me3P)4 (11), whose structure represents a relatively rare example of a crystallographically characterized trans isomer of this type. In 9, five of the ethyl ligands are distal, whereas in 10 all six substituents are distal. Attempts to prepare the sandwich dication [(HEB)2Ru]2+ gave instead [(HEB)Ru(H2O)3](BF4)2 (8), whose NMR and X-ray data reveal the 1,3,5-distal–2,4,6-proximal arrangement of ethyls both in the solid state and in solution. (HEB)Mn(CO)2Br (13) likewise adopts the 1,3,5-distal–2,4,6-proximal structure in the solid state but, surprisingly, there is no evidence for slowed ethyl rotation in solution.Key words: hexaethylbenzene conformations, hindered rotations, crystallography, NMR, ruthenium, manganese.


1988 ◽  
Vol 66 (12) ◽  
pp. 3120-3127 ◽  
Author(s):  
Howard C. Clark ◽  
George Ferguson ◽  
Mark J. Hampden-Smith ◽  
Heinz Ruegger ◽  
Barbara L. Ruhl

The reaction of Pt0(PCy3)2 with triphenyltin hydride yields cis-H(Ph3Sn)Pt(PCy3)2 as the initial product; isomerization to the trans isomer is accelerated by light, heat, and the presence of free phosphine. Both isomers have been characterized by multinuclear nmr spectroscopy; in particular, the 31P {1H} spectra in solution are correlated with the solid state CP/MAS 31P nmr spectra and the crystal structure. The crystal structures of trans-H(X3Sn)Pt(PCy3)2 X = Ph or Cl have been determined and the nature of the distortions produced by steric overcrowding is identified and discussed.



2001 ◽  
Vol 79 (3) ◽  
pp. 263-271
Author(s):  
Paul K Baker ◽  
Michael GB Drew ◽  
Deborah S Evans

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of 1-phenyl-1-propyne (MeC2Ph) in CH2Cl2, and in the absence of light, gave the bis(1-phenyl-1-propyne) complex [WI2(CO)(NCMe)(η2-MeC2Ph)2] (1) in 77% yield. Treatment of equimolar quantities of 1 and NCR (R = Et, i-Pr, t-Bu, Ph) in CH2Cl2 afforded the nitrile-exchanged products, [WI2(CO)(NCR)(η2-MeC2Ph)2] (2-5) (R = Et (2), i-Pr (3), t-Bu (4), Ph (5)). Complexes 1, 2, and 5 were structurally characterized by X-ray crystallography. All three structures have the same pseudo-octahedral geometry, with the equatorial sites being occupied by cis and parallel alkyne groups, which are trans to the cis-iodo groups. The trans carbon monoxide and acetonitrile ligands occupy the axial sites. In structures 1 and 2, the methyl and phenyl substituents of the 1-phenyl-1-propyne ligands are cis to each other, whereas for the bulkier NCPh complex (5), the methyl and phenyl groups are trans to one another. This is the first time that this arrangement has been observed in the solid state in bis(alkyne) complexes of this type.Key words: bis(1-phenyl-1-propyne), carbonyl, nitrile, diiodo, tungsten(II), crystal structures.



1980 ◽  
Vol 35 (2) ◽  
pp. 237-238 ◽  
Author(s):  
Martin Jansen

Abstract K3NO3 and RbsNO3 were prepared by solid state reaction of equimolar mixtures of K2O/KNO2 and Rb20/RbN02, respectively. According to X-ray powder photographs their crystal structures are derived from the perovs-kite structure. K3NO3 is isostructural with Na3NO3 (a = 521.7 pm, Z = 1), Rb3NO3 represents a tetragonally distorted variant with a = 770.5, c = 550.8 pm and Z = 2.



1997 ◽  
Vol 36 (22) ◽  
pp. 4968-4982 ◽  
Author(s):  
Yangzhen Ciringh ◽  
Scott W. Gordon-Wylie ◽  
Richard E. Norman ◽  
George R. Clark ◽  
Susan T. Weintraub ◽  
...  


2005 ◽  
Vol 277-279 ◽  
pp. 708-719
Author(s):  
Chang Seop Lee ◽  
Hee Jung Lee ◽  
Sung Woo Choi ◽  
Jahun Kwak ◽  
Charles H.F. Peden

A series of cation exchanged Y-zeolites were prepared by exchanging cations with various alkali (M+, M= Li, Na, K, Cs) metals. The structural and catalytic properties of the alkali metal exchanged Y-zeolites have been investigated by a number of analytical techniques. Comparative elemental analyses were determined by an Energy Dispersive Spectroscopy X-ray (EDS), X-ray Photoelectron Spectroscopy (XPS), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and X-ray Fluorescence (XRF) before and after cation substitution. The framework and non-framework Al coordination and the Si/Al ratios of the Y-zeolites were investigated by MAS Solid-State Nuclear Magnetic Resonance (NMR) spectroscopy. The Al NMR spectra were characterized by two 27Al resonance signals at 12 and 59 ppm, indicating the presence of the non-framework and framework Al respectively. The intensities of these resonances were used to monitor the amount of the framework and non-framework Al species in the series of exchanged zeolites. The 29Si NMR spectra were characterized by four resonance signals at -79, -84, -90, and -95 ppm. Changing the alkali metal cations in the exchanged Y-zeolites significantly altered the extent of the octahedral/tetrahedral coordination and the Si/Al ratio. The Fourier Transform Infrared spectra of the CO2 adsorbed on to the exchanged Y-zeolites showed a low frequency shift, as the atomic number of the exchanged alkali metal increased. In addition, the catalytic activity of these samples for NOx reduction were tested in combination with a non-thermal plasma technique and interpreted based on the above structural and spectroscopic information.



2011 ◽  
Vol 1304 ◽  
Author(s):  
Qingguo Meng ◽  
David C. Doetschman ◽  
Apostolos K. Rizos ◽  
Min-Hong Lee ◽  
Jürgen T. Schulte ◽  
...  

ABSTRACTAdsorption and chemistry of tripropylphosphate (TPP) in mesoporous NaX zeolite, which was templated by cationic templated polymer (polydiallyldimethylammonium chloride, PDADMAC) with two different length chains, was investigated. The structural properties of the zeolites were characterized by X-ray diffraction (XRD) and nitrogen adsorption analysis. The chemical activities of different zeolites toward the decomposition of TPP were determined with solid state 31P NMR spectra. After exposure of zeolites to TPP was sufficient and equilibrium was reached, a stoichiometric amount of water was also adsorbed and hydrolysis was observed. The TPP decomposition yields in different NaX zeolites were compared.





2019 ◽  
Vol 21 (19) ◽  
pp. 10070-10074 ◽  
Author(s):  
Kartik Pilar ◽  
Zeyu Deng ◽  
Molleigh B. Preefer ◽  
Joya A. Cooley ◽  
Raphaële Clément ◽  
...  

The complete 31P NMR chemical shift tensors for 22 inorganic phosphates obtained from ab initio computation are found to correspond closely to experimentally obtained parameters. The cases where correspondence is significantly improved upon geometry optimization point to the crystal structures requiring correction.



2004 ◽  
Vol 59 (6) ◽  
pp. 635-638 ◽  
Author(s):  
Norbert W. Mitzel ◽  
Udo Losehand

The compounds (H3C)2S, (H3Si)2S and (H3Ge)2S have been crystallised in situ on a diffractometer and their crystal structures determined by low-temperature X-ray diffraction. The molecules are present as monomers in the crystals. The aggregation of the molecules through secondary intermolecular contacts in the crystal is different: (H3C)2S is weakly associated into dimers by S···S contacts, whereas (H3Si)2S and (H3Ge)2S form Si···S and Ge···S contacts in an ice-analogous aggregation motif. Important geometry parameters are (H3C)2S: C-S 1.794(av) Å , C-S-C 99.2(1)°; (H3Si)2S: Si- S 2.143(1) Å , Si-S-Si 98.4°; (H3Ge)2S Ge-S 2.223(2) and 2.230(2) Å , Ge-S-Ge 98.2(1)◦.



1980 ◽  
Vol 33 (2) ◽  
pp. 313 ◽  
Author(s):  
PR Jefferies ◽  
BW Skelton ◽  
B Walter ◽  
AH White

Following the suggestion made earlier, on the basis of solution spectroscopy, that a number of eriostyl/nitrobenzoate compounds form charge-transfer self-complexes, a number of these have been investigated structurally by single-crystal X-ray diffraction methods in order to ascertain the presence or otherwise of such interactions in the solid state. The substances thus studied were eriostyl 3,5-dinitrobenzoate (1), eriostyl p-nitrobenzoate (2), tetrahydroeriostyl 3,5-dinitrobenzoate (3), and eriostemyl 3,5-dinitrobenzoate (4);* structure determinations in all cases, although displaying the presence of strong charge-transfer interactions from the two moieties of each molecule, show that the interactions in the solid state are intermolecular in nature.



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