Six-Membered Ring Chelate Complexes of Ru(II):  Structural and Photophysical Effects

2007 ◽  
Vol 46 (24) ◽  
pp. 10354-10364 ◽  
Author(s):  
Maria Abrahamsson ◽  
Hans-Christian Becker ◽  
Leif Hammarström ◽  
Celine Bonnefous ◽  
Charles Chamchoumis ◽  
...  
Keyword(s):  
Membered Ring ◽  
Chelate Complexes

Chemie polyfunktioneller Moleküle, 108 Tetraedrische Kupfer(I)-Chelatkomplexe der Liganden Bis(diphenylphosphino)amin und Bis(diphenylphosphino)methan / Chemistry of Polyfunctional Molecules, 108 [1] Tetrahedral Copper(I) Chelate Complexes with the Ligands Bis(diphenylphosphino)amine and Bis(diphenylphosphino)methane

1991 ◽  
Vol 46 (12) ◽  
pp. 1699-1705 ◽  
Author(s):  
Jochen Ellermann ◽  
Falk A. Knoch ◽  
Klaus J. Meier
Keyword(s):  
Membered Ring ◽  
Monoclinic Space Group ◽  
Direct Reaction ◽  
Conductivity Data ◽  
Chelate Complexes ◽  
X Ray ◽  
Lattice Constants ◽  
H Nmr ◽  
Highly Strained ◽  
Nitrate Anions

Reaction of [Cu(PPh3)2(NO3)] (1) in acetone with bis(diphenylphosphino)amine (dppa, 2) yields [Cu(dppa)(PPh3)2]+NO3- (3a). [Cu(dppa)(PPh3)2]+PF6- (3b) has been synthesized by metatheses of 3a with NH4PF6. The salt [Cu(dppm)(PPh3)2]+PF6- (5b) has been prepared by an one batch reaction of [Cu(PPh3)2(NO3)] (1), bis(diphenylphosphino)methane (dppm, 4) and NH4PF6 in methanol, because [Cu(dppm)(PPh3)2]+NO3- (5a) could not be isolated by the direct reaction of 1 with 4. The IR, Raman, 31P{1H} NMR, 1H{31Ρ} NMR as well as the conductivity data are reported and discussed together with the X-ray crystal structure of 3a · 1.8 (CH3)2CO. The structure consists of copper atoms coordinated tetrahedrally by two PPh3 ligands and the chelating dppa ligand and features a highly strained four-membered ring. The distorted tetrahedral cations are hydrogen bridged to the nitrate anions. The colourless needles of 3a· 1.8 (CH3)2CO crystallize in the monoclinic space group C 2/c, with the lattice constants a = 4189.2(27); b = 1223.7(8); c = 2717.8(15) pm;β = 113.16(4)°.

Variable Temperature Nuclear Magnetic Resonance Studies of Some Five-Membered Ring Chelate Complexes

1975 ◽  
Vol 53 (7) ◽  
pp. 1038-1045 ◽  
Author(s):  
William R. Cullen ◽  
Laurance D. Hall ◽  
John E. H. Ward
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Temperature Dependence ◽  
Significant Variation ◽  
Conformational Equilibrium ◽  
Variable Temperature ◽  
Membered Ring ◽  
Coupling Constants ◽  
Chelate Complexes ◽  
Magnetic Resonance Studies

The temperature dependence of the n.m.r. spectra of nine ditertiary arsine chelate complexes of formula (CH3)2AsC(3)(3′)C(4) (4′)As(CH3)2M(CO)3X has been studied (M = Mo, Cr; X = CO; M = Mn; X = halogen; (3), (3′), (4), (4′) = H, F, Si(CH3)3, CN; but not all combinations ). Significant variation in coupling constants, indicating a shift in the conformer populations, was found only for the CHFCF2 bridged Mn(CO)3Cl complex, the CH2CF2 bridged Mn(CO)3Cl complex, and the CHFCHF bridged Mo(CO)4 complex. In the last case the 3JHH coupling constants were used to estimate ΔH ∼ 1 kcal/mol and ΔS ∼ 3 e.u for the conformational equilibrium.

Darstellung des Stibinoschwefeldiimid-Achtrings tBuSb(NSN)2SbtBu und einiger seiner Carbonylmetall-Derivate / Synthesis of the Eight-Membered Stibino-Sulfur Diimide Ring tBuSb(NSN)2SbtBu and Some of its Carbonylmetal Derivatives

1988 ◽  
Vol 43 (10) ◽  
pp. 1274-1278 ◽  
Author(s):  
Max Herberhold ◽  
Klaus Schamel
Keyword(s):  
Membered Ring ◽  
Nitrogen Heterocycle ◽  
Chelate Complexes

Abstract The first antimony-sulfur-nitrogen heterocycle, tBuSb(NSN)2SbtBu (1b)**, has been prepared from the reaction of tBuSbCl2 with the salt K2SN2. It forms stable chelate complexes of the type (CO)4M[tBuSb(NSN)2SbtBu] (M = Cr (3b), Mo (4b), W (5b)). The pentacarbonylchromium complex (CO)5Cr[tBuSbCl2] reacts with K2SN2 to give the mononuclear derivative (CO)5Cr[tBuSb(NSN)2SbtBu] (2b) containing the eight-membered ring 1b, whereas the corre-sponding complexes (CO)5Cr[R2SbCl] (R = tBu, Ph) are converted into binuclear sulfur diimide derivatives (CO)5Cr[R2Sb(NSN)SbR2]Cr(CO)5 (R = tBu (6b). Ph (7b)). The new stibino-sulfur diimides 1b-7b have been characterized by IR and NMR (1H and 13C) spectroscopy.

Six-membered ring chelate complexes of Pd(II) and Pt(II) derived from di-(2-pyridyl)pyrimidin-2-ylsulfanylmethane

Polyhedron ◽  
2011 ◽  
Vol 30 (7) ◽  
pp. 1324-1329 ◽  
Author(s):  
Gabriela Rodríguez-García ◽  
Noemí Andrade-López ◽  
José G. Alvarado-Rodríguez ◽  
Diego Martínez-Otero ◽  
Rafael Moreno-Esparza ◽  
...  
Keyword(s):  
Membered Ring ◽  
Chelate Complexes

Five-membered ring chelate complexes of Ni(II), Pd(II) and Pt(II) derived of di-(2-pyridyl)-N-ethylimine

Polyhedron ◽  
2010 ◽  
Vol 29 (11) ◽  
pp. 2304-2310 ◽  
Author(s):  
Noemí Andrade-López ◽  
Tracy A. Hanna ◽  
José G. Alvarado-Rodríguez ◽  
Adriana Luqueño-Reyes ◽  
Bernat A. Martínez-Ortega ◽  
...  
Keyword(s):  
Membered Ring ◽  
Chelate Complexes

An Alternate Energy-Conserved Pathway for the Morita-Baylis-Hillman (MBH) Reaction

2020 ◽  
Author(s):  
Veejendra Yadav
Keyword(s):  
Proton Transfer ◽  
Transition State ◽  
Lower Energy ◽  
Aldol Reaction ◽  
Membered Ring ◽  
Ammonium Ion ◽  
Alternate Energy ◽  
Ring Transition State ◽  
Mbh Reaction

An new overall lower energy pathway for the amine-catalysed Morita-Baylis-Hillman reaction is proposed from computations at the M06-2X/6-311++G(d,p) level. The pathway involves proton-transfer from the ammonium ion to the alkoxide formed from the aldol reaction through a seven-membered ring transition state (TS) structure followed by highly exothermic Hofmann<i> </i>elimination through a five-membered ring TS structure to form the product and also release the catalyst to carry on with the process all over again.

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