Search results for "Coupling"

Strong Ferromagnetic Coupling in Linear Mixed μ-Acetato, μ-Hydroxo Trinuclear Copper(II) Complexes withN-sulfonamide derivatives − Synthesis, Structu…

2002

Tetramethylditin complexes: A general method for the preparation of a class of compounds with an unusual tintin bond

1980

Abstract The preparation and physical and spectroscopic properties of eight compounds of the type Me4Sn2X2 (X  O2CR, S2CNR2, S2P(OR)2) are described, starting from Me4Sn2Cl2. The spectroscopic data indicate that X functions as an isobidentate ligand. The tintin coupling constants are extremely large (ca. 11–15 kHz), and can be correlated with the pKa values of the corresponding acids HX.

Die kopplungskonstanten nJ(SnC) und n+1J(SnH) ineinigen verbindungen mit der tetramethyldizinngruppe

1977

Abstract Comparison of data on seven compounds containing the group tetramethylditin shows a variation in the coupling constants depending on the lone pair electrons of the substituents.

Magnetic coupling in discrete cyano-bridged Mn(III)-Fe(III) motifs: synthesis, crystal structure, magnetic properties and theoretical study.

2010

The preparation, crystal structures and magnetic properties of the heterobimetallic complexes of formula [Mn(III)(n-MeOsalen)(H(2)O)(mu-CN)Fe(III)(bpym)(CN)(3)]·mH(2)O with n = m = 3 (1) and n = 4 and m = 2 (2) [n-MeOsalen(2-) = N,N'-ethylenebis(n-methoxysalicylideneiminate) dianion and bpym = 2,2'-bipyrimidine] are reported. 1 and 2 are dinuclear neutral species where the cyano-bearing low-spin unit [Fe(III)(bpym)(CN)(4)](-) acts as a monodentate ligand towards the [Mn(III)(SB)(solv)(x)](+) entity (SB = tetradentate Schiff-base) through one of its four cyano groups. Adjacent heterobimetallic units are interlinked through hydrogen bonds involving the coordinated water molecule of one dinucl…

Structural, magnetic and related attributes of some oximate-bridged tetranuclear nickel(ii) rhombs and a dinuclear congenerElectronic supplementary i…

2003

New oximate-bridged tetranuclear nickel(II) complexes of compositions {Ni(Dien)}2(μ3-OH)2{Ni2(Moda)4}(ClO4)2·Solv (Solv = H2O, 1a; Solv = 2CH3NO2, 1b; Solv = 2H2O·2C4H8O2, 1c), {Ni(Sdien)}2(μ3-OH)2{Ni2(Moda)4}(ClO4)2·H2O (2), {Ni(Odien)}2(μ3-OH)2{Ni2(Moda)4}(ClO4)2·0.6H2O (3), {Ni(Dien)}2(μ3-OH)2{Ni2(Inaf)4}(ClO4)2·CH3NO2 (4) and {Ni(Odien)}2(μ3-OH)2{Ni2(Inaf)4}(ClO4)2·2NaClO4·2H2O (5) and the dinuclear complex (Ni{Odien})2(Moda)2(ClO4)2 (6) have been prepared (Dien = 1,5-diamino-3-azapentane, Odien = 1,5-diamino-3-oxapentane, Sdien = 1,5-diamino-3-thiapentane, ModaH = butane-2,3-dione monooxime, InafH = phenylglyoxaldoxime). X-ray examination revealed similar structures for 1a, 1b, 1c, 2 a…

A Novel Dinuclear Fe II Spin‐Crossover Complex Based on a 2,2‐Bipyrimidine Bridge Ligand: [Fe(CH 3 bipy)(NCS) 2 ] 2 bpym

2004

The dinuclear iron(II) complex {[Fe(CH3bipy)(NCS)2]2bpym} has been synthesised and its crystal structure determined at 293 K. The magnetic properties display intramolecular antiferromagnetic coupling at 1 bar (J = −4.2 cm−1), and the onset of a pressure-induced spin conversion is observed at 11 kbar. Magnetic field Mossbauer measurements have been carried out at 4.2 K, and indicate that the HS species correspond to [HS-HS] pairs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Ferromagnetic coupling through spin polarization in the hexanuclear [MnII(3)CuII(3)] complex.

2004

A novel Cu(II)-Mn(II) hexanuclear complex of formula [[MnCuL](3)(tma)](ClO(4))(3).8H(2)O [H(2)L = macrocyclic Robson proligand; H(3)tma = trimesic acid] has been obtained by connecting three heterobinuclear [Cu(II)Mn(II)L](2+) cationic species through the trimesate anion. The complex exhibits a C(3) rotational symmetry, imposed by the geometry of the bridging ligand. The interaction within each Mn(II)-Cu(II) pair is antiferromagnetic (J = -16.7 cm(-1)). A weak ferromagnetic coupling among the three S = 2 resulting spins through the tricarboxylato bridge leads to a S = 6 ground spin state, for which the spin polarization mechanism is responsible.

Ligand Effect on Iron-Catalyzed Cross-Coupling Reactions: Evaluation of Amides as O-Coordinating Ligands

2019

The development of new highly efficient O‐coordinating ligands for iron‐catalyzed C(sp2)−C(sp3) cross‐coupling reactions is reported. A structure‐reactivity study on the effect of amides as ligands in the industrially‐important iron‐catalyzed cross‐coupling of aryl chlorides with challenging organometallics possessing β‐hydrogens was performed. Investigation of a series of new 21 ligands that rationally vary in O‐coordination aptitude as well as sterics around the amide bond pinpointed the features that are important for catalysis. The study led to the discovery of several highly efficient ligands for cross‐coupling, including TMU (TMU=tetramethylurea), N‐cyclic and coordinating benzamides.…

Palladium-Based Metal Organic Frameworks as Heterogeneous Catalysts for C-C Couplings

2022

Among the various cross coupling reactions, C−C cross coupling reaction has attracted many researchers to investigate in the last four decades. The continuous, constant, and consistent progress in this field fetched a Noble prize in 2010, showing the importance of this reaction in diversified fields. Among the various transition metals studied for this reaction, Pd is one of the metals that has exhibited the highest activity due to its unique features and reactivity. Although Pd-based homogeneous catalyst was the preferred choice for many researchers, the field slowly diverted towards the development of Pd-based heterogeneous catalysts for C−C coupling reactions. This is obviously due to th…

On the electronic coupling of the C=O stretching vibrations in Cl(2)Pt(malonate)(-).

2001

Ab initio calculations on the complex Cl(2)Pt(malonate)(-) have been performed to estimate the magnitude and the source of the splitting between the symmetric and antisymmetric C=O stretches. It is shown that a large part of the splitting can result from pure electronic coupling mediated via the pi-structure of the ligand. Calculations have also been performed on the free ligand malonate(-) and the neutral malonaldehyde that show decreasing electronic coupling, which is consistent with the decreasing resonance stabilization. A simple effective C=O interaction potential has been produced for Cl(2)Pt(malonate)(-) that is used to estimate the electronic splitting of the 1600 cm(-1) IR band to …