A pentaammineruthenium(III) dimer with the novel bridging ligand 4,4′-dicyanamidobiphenyl dianion

1996 ◽  
Vol 74 (11) ◽  
pp. 2201-2208 ◽  
Author(s):  
Christopher A. White ◽  
Corinne Bensimon ◽  
Robert J. Crutchley ◽  
Manuel A.S. Aquino ◽  
J.E. Greedan
Keyword(s):  
Cyclic Voltammetry ◽  
Nmr Spectroscopy ◽  
Mixed Valence ◽  
The Novel ◽  
Temperature Dependent ◽  
Monoclinic Crystal ◽  
H Nmr ◽  
Weakly Coupled ◽  
Anti Conformation ◽  
Mixed Valence Complex

The novel ligand 4,4′-dicyanamidobiphenyl dianion (bp2−) has been synthesized and characterized by 13C NMR spectroscopy, cyclic voltammetry, and crystallography. The crystal structure of [Ph4As]2[bp]•H2O showed that bp2− is approximately planar with a dihedral angle of 8.2° between phenyl ring planes and the cyanamide groups in an anti conformation. The water of crystallization is asymmetrically hydrogen bonded between cyanamide groups of adjacent bp2− ions. The crystal data for C62H48N4As2 + H2O are monoclinic crystal system and space group P21/c with a = 12.998(5) Å, b = 13.465(4) Å, c = 28.703(13) Å, β = 98.94(3)°, V = 4963(3) Å3 and Z = 4. The structure was refined by using 4555 reflections with I > 2.5σ(I) to an R factor of 0.058. The complex, [{(NH3)5Ru)2(μ-bp)][X]4, where X = tosylate or PF6− ions, was also synthesized and characterized by 1H NMR spectroscopy, cyclic voltammetry, spectroelectrochemistry, and temperature-dependent magnetic susceptibility measurements. From cyclic voltammetry measurements, the comproportionation constants to form the mixed-valence complex [{(NH3)5Ru)2(μ-bp)]3+ were estimated to be 4.1, 16, and 22 in water, acetonitrile, and nitromethane, respectively. The trend and magnitude of Kc suggests solvent valence trapping of a weakly coupled Class II ion. The MMCT band of the mixed-valence complex had to be deconvoluted from the low-energy LMCT band and had the following properties in acetonitrile, νmax = 8400 cm−1, εmax = 3300 M−1 cm−1, and Δν1/2 = 3300 cm−1. The weak superexchange mediating properties of bp2− compared to 1,4-dicyanamidobenzene dianion were suggested to arise from the larger barrier to the formation of the radical anion bp−. Key words: cyanamido, mixed valence, superexchange, ruthenium.

Die intramolekulare Beweglichkeit von Alkinen in Wolframkomplexen des Typs C5H5W(CO)(L)R (L = Alkin; R = CH3, C6H5) / The Intramolecular Mobility of Alkynes in Tungsten Compounds of the Type C5H5W(CO)(L)R (L = Alkyne; R = CH3, C6H5)

1977 ◽  
Vol 32 (2) ◽  
pp. 144-147 ◽  
Author(s):  
H. G. Alt ◽  
W. Stadler
Keyword(s):  
Nmr Spectroscopy ◽  
Temperature Dependent ◽  
H Nmr ◽  
Intramolecular Mobility ◽  
Type C

Complexes of the type C5H5W(CO)(L)R (L = alkyne; R = CH3, C6H5) are obtained by irradiation of a solution containing both C5H5W(CO)3R and L. The intramolecular mobility of the π-bonded acetylene in the 16-electron complexes C5H5W(CO)(L)R can be demonstrated by temperature-dependent 1H NMR spectroscopy.

Dioxa-dithia Macrocycle-bridged Dimeric with Hexakis(alkylthio) Substituents and Network Polymer Phthalocyanines

1997 ◽  
Vol 01 (01) ◽  
pp. 67-76 ◽  
Author(s):  
A. G. GÜREK ◽  
Ö. BEKARO ĞLU
Keyword(s):  
Electrical Conductivity ◽  
Nmr Spectroscopy ◽  
Chemical Doping ◽  
The Novel ◽  
Conductivity Measurements ◽  
Network Polymer ◽  
Network Polymers ◽  
H Nmr ◽  
Elemental Analyses ◽  
C Nmr

1,7-dithia (12-crown-4)-bridged phthalocyanine network polymers were prepared from tetracyanodibenzo-[1,7-dithia(12-crown-4)]. In addition, the synthesis of two 1,7-dithia (12-crown-4) linked peripherally octa-substituted dimeric phthalocyanines, which contain a combination of hexakis(alkylthia) side chains, is described. These extremely soluble compounds were prepared by the condensation of an iminoisoindoline derivative and a subphthalocyanine. The novel compounds are characterized by elemental analyses, UV/vis, IR, mass, 1 H NMR and 13 C NMR spectroscopy. The electrical conductivity measurements of three of the four network polymers were unsuccessful; however chemical doping with NOBF 4 could be increased to a measurable value. The electrical conductivity of the dimeric phthalocyanines are in the semiconductor range.

EM studies of long-lived fiber gels complemented by solid state 2H-NMR spectroscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 852-853
Author(s):  
Sönke Svenson
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Sodium Dodecylsulfate ◽  
Preparative Method ◽  
Temperature Dependent ◽  
H Nmr ◽  
Sds Micelles ◽  
Dispersed Particles ◽  
Aqueous Gels ◽  
High Concentrations

Aqueous gels (1%) consisting of the amphiphilic N-octyl-D- gluconamide (D-Glu-8) usually crystallize within a few hours.They remain stable for more than five months if 0.4% of sodium dodecylsulfate (SDS) is added. It was shown by electron microscopy that the gels are formed by helical fibers of at least bimolecular thickness (4 nm) and of several micrometers length. Randomly dispersed particles with a mean diameter of 5 nm, which are assumed as micelles, were also observed on micrographs (Fig.1).To provide evidence for this assumption and to rule out the possibility of artefacts introduced by the preparative method, we applied an additional technique, namely solid state 2H-NMR spectroscopy. The spectra point out the temperature dependent equilibrium between “solid” fibers and micelles, as represented by the Pake powder spectrum and the isotropic central singlet (Fig.2). The micellar part of the equilibrium is strongly enhanced in the presence of detergents such as SDS. High concentrations of SDS micelles extend the gel’s lifetime, presumably because these micelles dissolve the crystallization nuclei of D-Glu-8 and thus, prevent further crystal growth.

Mixed-valence properties of a dinuclear ruthenium complex bridged by bis(phenylcyanamido)tetrazine

2014 ◽  
Vol 92 (11) ◽  
pp. 1081-1085 ◽  
Author(s):  
Fatemeh Habibagahi ◽  
Robert J. Crutchley
Keyword(s):  
Ruthenium Complex ◽  
Mixed Valence ◽  
Transition Dipole Moment ◽  
The Novel ◽  
Transition Dipole ◽  
H Nmr ◽  
Bridging Ligand ◽  
Metal Metal ◽  
Dinuclear Ruthenium ◽  
The Stability

The novel bridging ligand 3,6-bis(phenylcyanamido)-1,2,4,5-tetrazine (tdpcH2) and its dinuclear complex [{Ru(ttpy)(bpy)}2(μ-tdpc)][PF6]2 were prepared and characterized by elemental analysis and 1H NMR spectroscopy. Cyclic voltammetry and vis-NIR and IR spectroelectrochemistry of [{Ru(ttpy)(bpy)}2(μ-tdpc)]2+ showed that [{Ru(ttpy)(bpy)}2(μ-tdpc)]3+ is a Class II mixed-valence system with metal−metal coupling of 400 cm−1 assuming a transition dipole moment length of 21 Å. DFT calculations of tdpc2− suggested that the stability of the HOMO results in weak metal−metal coupling via the hole-superexchange mechanism.

scholarly journals Synthesis and antimicrobial activity of N-[4-(3-Oxo-3-phenyl-propenyl)-phenyl]-2-(4-phenyl-5-pyridine-4yl-4H-[1,2,4]triazole-3-ylsulfanyl)-acetamide

2017 ◽  
Vol 9 (2) ◽  
pp. 43
Author(s):  
Jyotindra Mahyavanshi ◽  
Maharshi Shukla ◽  
Kokila Parmar
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Nmr Spectroscopy ◽  
The Novel ◽  
H Nmr ◽  
In Vitro Antibacterial Activity ◽  
Ft Ir ◽  
Anti Fungal ◽  
New Compounds

<p class="Default">A new series of<em> </em><em><span>N-</span></em><span>[4-(3-Oxo-3-phenyl-propenyl)-phenyl]-2-(4-phenyl-5-pyridine-4yl-<em>4H</em>-[1,2,4]triazole-3-ylsulfanyl)-acetamide</span> have been synthesized by the claisen-schimodt condensation of <em>N</em>-(4-Acetyl-phenyl)-2-(4-phenyl-5-pyridin-4-yl-4<em>H-</em>[1,2,4]triazole-3-ylsulfanyl) and various aldehyde. The novel compounds structure has been established on the basis of their substituted aldehyde derivatives. All the compounds were characterized by FT-IR, Mass, and <sup>1</sup>H-NMR spectroscopy. These new compounds were evaluated for their in vitro antibacterial activity and anti-fungal activity.</p>

Metall-π-Komplexe von Benzolderivaten, XLaSelen in der Peripherie des Bis(benzol)chroms: Darstellung, Strukturdynamik und Redoxverhalten eines neuen Hetera-[3]-chromocyclophans / Metal-π Complexes of Benzene Derivatives, XLaSelenium in the Periphery of Bis(benzene)chromium: Synthesis, Structural Dynamics, and Redox Behavior of a New Hetera-[3]-chromocyclophane

1992 ◽  
Vol 47 (8) ◽  
pp. 1157-1164 ◽  
Author(s):  
Christoph Elschenbroich ◽  
Heike Burdorf ◽  
Helmut Burdorf ◽  
Dagmar Mahrwald ◽  
Bernhard Metz
Keyword(s):  
Cyclic Voltammetry ◽  
Nmr Spectroscopy ◽  
Redox Potential ◽  
Structural Dynamics ◽  
Half Life ◽  
Redox Behavior ◽  
Benzene Derivatives ◽  
Subsequent Reaction ◽  
H Nmr ◽  
Electron Donation

Lithiation of bis(benzene)chromium and subsequent reaction with Ph2Se2 or Se and CH3I, respectively, afforded the complexes (PhSe-η6-C6H5)2Cr (6) and (MeSe-η6-C6H5)2Cr (8), the latter being convertible into interannularly bridged (MeSe-η6-C6H5)2Cr[M(CO)4] (9-11, M = Cr, Mo, W). According to 1H NMR spectroscopy, 9 undergoes both bridge inversion and reversal, the former displaying spectral coalescence at 283 K (ΔGc≠ = 55.9 kJ mol-1) whereas the latter is still rapid at 200 K. Substitution of H for –SeMe and addition of a Cr(CO)4 unit effect anodic shifts of the redox potential E1/2(+/0) of 95 mV/SeMe and 230 mV/Cr(CO)4. Despite electron donation from the bis(arene)metal backbone 8 is a fairly weak ligand, cleavage of the interannular bridge occuring with the half life τ1/2 = 41.4 min (9→8) and τ1/2 = 5.8 s (9+•→8+) as inferred from cyclic voltammetry in DME at 293 K.

scholarly journals Synthesis and NMR studies of malonyl-linked glycoconjugates of N-(2-aminoethyl)glycine. Building blocks for the construction of combinatorial glycopeptide libraries

2016 ◽  
Vol 12 ◽  
pp. 1939-1948 ◽  
Author(s):  
Markus Nörrlinger ◽  
Sven Hafner ◽  
Thomas Ziegler
Keyword(s):  
Nmr Spectroscopy ◽  
Formic Acid ◽  
Building Blocks ◽  
Propanoic Acid ◽  
Temperature Dependent ◽  
Nmr Studies ◽  
H Nmr ◽  
Fmoc Group ◽  
Aqueous Formic Acid ◽  
Coalescence Temperature

Four glycoconjugate building blocks for the construction of combinatorial PNA like glycopeptide libraries were prepared in 75–79% yield by condensing tert-butyl N-[2-(N-9-fluorenylmethoxycarbonylamino)ethyl]glycinate (AEG) 5 with 3-oxo-3-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosylamino)- (6a), 3-oxo-3-(β-D-galactopyranosylamino)- (6b), 3-oxo-3-(2-acetamido-2-deoxy-3,4,6-tetra-O-acetyl-β-D-glucopyranosylamino)- (6c) and 3-oxo-3-(2-acetamido-2-deoxy-3,4,6-tetra-O-acetyl-β-D-galactopyranosylamino)propanoic acid (6d), respectively. The resulting AEG glycoconjugates 1a–d were converted into the corresponding free acids 2a–d in 97–98% yield by treatment with aqueous formic acid. The Fmoc group of compound 1c was removed and the intermediate amine 9 was condensed with 2a to afford the corresponding glycosylated AEG dipeptide 4 in 58% yield. All glycoconjugate building blocks showed the presence of cis and trans rotamers. Compounds 1a, 1b and 4 were subjected to temperature dependent 1H NMR spectroscopy in order to determine the coalescence temperature which resulted in calculated rotation barriers of 17.9–18.3 kcal/mol for the rotamers.

Photochemische Umsetzungen von η5-Indenyl-tricarbonyl-methyl-molybdän und -wolfram, C9H7M(CO)3CH3 (M = Mo, W), mit Acetylenen / Photochemical Reactions of Indenyl-tricarbonyl-methyl-molybdenum and -tungsten, C9H7M(CO)3CH3 (M = Mo, W), with Acetylenes

1977 ◽  
Vol 32 (10) ◽  
pp. 1139-1144 ◽  
Author(s):  
H. G. Alt
Keyword(s):  
Nmr Spectroscopy ◽  
Uv Irradiation ◽  
Photochemical Reactions ◽  
Temperature Dependent ◽  
H Nmr ◽  
Intramolecular Mobility ◽  
Indenyl Complexes ◽  
And Tungsten

The photoreaction of the indenyl complexes C9H7M(CO)3CH3 (M = Mo, W) with alkynes (L) in solution leads to 1:1 adducts, which are found to be metallocyclic alkenylketone compounds C9H7M(CO)2(L-COCH3). UV irradiation of C9H7W(CO)3CH3 in the presence of either acetylene or methylacetylene also gives substituted derivatives C9H7W(CO)(L)CH3 in low yields. For these compounds, the intramolecular mobility of the π-bonded alkyne ligand can be demonstrated by temperature-dependent 1H NMR spectroscopy.

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