scholarly journals Carbene Character in a Series of Neutral PCcarbeneP Cobalt(I) Complexes – Radical Carbenes Versus Nucleophilic Carbenes

2021 ◽  
Author(s):  
Marissa Clapson ◽  
Justin Kirkland ◽  
Warren Piers ◽  
Daniel Ess ◽  
Benjamin Gelfand ◽  
...  
Keyword(s):  
Benzoic Acid ◽  
Alkyl Derivative ◽  
Pincer Ligands ◽  
Aryl Group ◽  
Nucleophilic Carbenes ◽  
Amine Complexes ◽  
Square Planar ◽  
Tetrahedral Complexes ◽  
Trityl Radical ◽  
Plat Form

Cobalt(I) complexes supported by a series of PCcarbeneP pincer ligands of varying donicity, differing in the aryl group linking the phosphine arms with the anchoring carbon donor, are described. Addition of the proligands to cobalt bromide results in the formation of a series of cobalt(II) tetrahedral complexes, Ln-1, which serve as excellent precur-sors to the corresponding PCalkylP and PCcarbeneP complexes. Square planar cobalt PCcarbeneP complexes, L2R-3-X (X = Cl, Br), are readily synthesized by addition of a bulky aryloxide radical to the corresponding PCalkylP complex, L1-2-Br or via addition of L2R to ClCo(PPh3)3 in the presence of trityl radical or by addition of NaHBEt3 and trityl radical to iso-lated L2R-1. For the L2NMe2 PCcarbeneP complexes, salt metathesis reactions with either CsOH·H2O, LiCH2TMS, or LiNH2 result in the corresponding hydroxo, alkyl, and amine complexes, L2NMe2-3-R (R = OH, CH2TMS, NH2). Reaction of L2NMe2-3-OH with benzoic acid affords the 2-O2CPh derivative The nature of the carbene bond in either ligand plat-form as well as the effects of the X-type capping ligand on the Co=C bond are explored computationally and show that triplet structures are relatively more stable in for the less electron donating ligand L1 while singlet Co(I) carbenes dominate for the more electron rich L2 derivatives. For L2NMe2 complexes, the effect of the trans ligand X was also probed. Pi donors imbue the carbene with singlet character while the strongly  donating alkyl derivative exhibits significant triplet character.

Structure of the complexes of ethylenediphosphinetetraacetic acid in solution

1985 ◽  
Vol 50 (2) ◽  
pp. 445-453 ◽  
Author(s):  
Jana Podlahová ◽  
Josef Šilha ◽  
Jaroslav Podlaha
Keyword(s):  
Metal Ion ◽  
Carboxyl Groups ◽  
Complex Solution ◽  
Square Planar ◽  
Weak Complexes ◽  
Carboxylic Groups ◽  
Uv Visible ◽  
The Stability ◽  
Tetrahedral Complexes ◽  
Free Carboxyl

Ethylenediphosphinetetraacetic acid is bonded to metal ions in aqueous solutions in four ways, depending on the type of metal ion: 1) through an ionic bond of the carboxylic groups to form weak complexes with a metal:ligand ratio of 1 : 1 (Ca(II), Mn(II), Zn(II), Pb(II), La(III)); 2) through type 1) bond with contributions from weak interaction with the phosphorus (Cd(II)); 3) through coordination of the ligand as a monodentate P-donor with the free carboxyl groups with formation of 2 : 1 and 1 : 1 complexes (Cu(I), Ag(I)); 4) through formation of square planar or, for Hg(II), tetrahedral complexes with a ratio of 1 : 2 with the ligand as a bidentate PP-donor with the free carboxyl groups (Fe(II), Co(II), Ni(II), Pd(II), Pt(II)). On acidification of the complex solution, the first two protons are bonded to the carboxyl groups. The behaviour during further protonation depends on the type of complex: in complexes of types 1) and 2) phosphorus is protonated and the complex dissociates; in complexes of types 3) and 4) the free carboxyl groups are protonated and the phosphorus-metal bond remains intact. The results are based on correlation of the stability constants, UV-visible, infrared, 1H and 31P NMR spectra and magnetic susceptibilities of the complexes in aqueous solution.

Composés de coordination de molécules soufrées. II. Complexes pseudo-tétraédriques et plan du nickel(II) avec quelques dithiole-1,2 thiones-3

1971 ◽  
Vol 49 (15) ◽  
pp. 2598-2604 ◽  
Author(s):  
François Yves Petillon ◽  
Jacques Emile Guerchais
Keyword(s):  
Solid State ◽  
Electronic Spectra ◽  
Spectral Region ◽  
Far Infrared ◽  
Infrared Spectral Region ◽  
Planar Complex ◽  
Square Planar ◽  
Infrared Spectral ◽  
Tetrahedral Complexes

The study of the far infrared spectral region permits one to distinguish between the pseudo-tetrahedral complexes NiI2L2 (L = R1R2C3S3 where R1 = CH3 and R2 = H, R1 = R2 = CH3, R1 = C4H3S and R2 = H) and the square planar complex NiI2L′2 (L′ = R1R2C3S3 where R1 = C6H5 and R2 = H). The electronic spectra recorded in the solid state confirm the distinction. The displacement of the band νC=S of the molecule 1,2-dithio-1-3-thione which enters the sphere of coordination is more marked in the complexes of cobalt(II) than in the corresponding nickel(II) complexes.

Zn(II), Co(II) and Ni(II) complexes of a phosphorylthiourea derivative of 4-[(EtO)2P(O)CH2]-C6H4-NHC(S)NHP(O)(OiPr)2

2010 ◽  
Vol 75 (5) ◽  
pp. 507-515 ◽  
Author(s):  
Maria G. Babashkina ◽  
Damir A. Safin
Keyword(s):  
Nitrogen Atom ◽  
Spectral Data ◽  
Sulfur Atom ◽  
Metal Cation ◽  
Potassium Salt ◽  
Thiourea Derivative ◽  
Square Planar ◽  
Phosphoryl Groups ◽  
Tetrahedral Complexes ◽  
Planar Environment

The reaction of O,O′-diisopropyl phosphorisothiocyanatidate, (iPrO)2P(O)NCS, with diethyl-(4-aminobenzyl)phosphonate leads to the new N-phosphorylated thiourea derivative, 4-[(EtO)2P(O)CH2]-C6H4NHC(S)NHP(O)(OiPr)2 (HL). The reaction of its potassium salt KL with Zn(II) or Co(II) in aqueous EtOH leads to the complexes of formulae M(L-O,S)2 (ZnL2, CoL2). The metal cation in all complexes is coordinated by two deprotonated ligands through the sulfur atoms of the thiocarbonyl groups and the oxygen atoms of the phosphoryl groups. The reaction of KL with Ni(II) leads to the formation of two types of complexes: the blue Ni(L-N,S)2 complex, where the ligand is coordinated through the nitrogen atom of the phosphorylamide group and the sulfur atom of the thiocarbonyl groups and light red Ni(L-O,S)2 complex with the same coordination of L– anion as it was observed for ZnL2 and CoL2. According to UV/Vis spectral data, it was established that the metal cation of Ni(L-N,S)2 is in a square-planar environment in CH2Cl2, whereas the Ni(L-O,S)2 complex shows features of tetrahedral complexes.

Axial Chirality in Square-Planar Metal Complexes

1998 ◽  
Vol 53 (9) ◽  
pp. 1035-1038 ◽  
Author(s):  
Dieter Enders ◽  
Heike Gielen ◽  
Klaus Breuer
Keyword(s):  
Transition Metals ◽  
Metal Complexes ◽  
Axial Chirality ◽  
Late Transition Metals ◽  
Nucleophilic Carbenes ◽  
Square Planar ◽  
Late Transition ◽  
Planar Ligands

Metal complexes with a square-planar arrangement of ligands are frequently found for the late Transition Metals. The incorporation of C1-symmetrical planar ligands (e.g. nucleophilic carbenes) in an orientation perpendicular to the square-plane of the complex leads to various isomers which are characterized by means of an axis of chirality employing the well established Cahn-Ingold-Prelog -R/S-nomenclature.

scholarly journals Tuning two-electron transfer in terpyridine-based platinum(ii) pincer complexes

RSC Advances ◽  
2019 ◽  
Vol 9 (37) ◽  
pp. 21116-21124
Author(s):  
Seher Kuyuldar ◽  
Clemens Burda ◽  
William B. Connick
Keyword(s):  
Electron Transfer ◽  
Oxidation Process ◽  
Pincer Complexes ◽  
Pincer Ligands ◽  
Square Planar

Square planar Pt(ii) terpyridine complexes with pincer ligands undergo two-electron oxidation and variation in the ligand substituents allows for tuning of the two-electron oxidation process over a 260 mV range.

scholarly journals Synthesis, Characterization, Thermogravimetric and Antioxidant Studies of New Cu(II), Fe(II), Mn(II), Cu(II), Zn(II), Co(II) and Ni(II) Complexes with Benzoic Acid and 4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione

2019 ◽  
Vol 11 (1) ◽  
pp. 60 ◽  
Author(s):  
Festus Sunday Fabiyi ◽  
Adesoji Alani Olanrewaju
Keyword(s):  
Benzoic Acid ◽  
13C Nmr ◽  
Metal Ion ◽  
Magnetic Moments ◽  
Molecular Structures ◽  
Planar Geometry ◽  
Thermally Stable ◽  
1H And 13C Nmr ◽  
Square Planar ◽  
Oxygen Atoms

Six new Mn(II), Fe(II), Co(II), Ni (II), Cu(II) and Zn(II) complexes with benzoic acid (L) and 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione (L1), of the molecular formulae [MnLL1]·H2O (1), [FeLL1]·H2O (2), [CoLL1] (3), [NiLL1]·H2O (4), [CuLL1] (5) and [ZnLL1] (6), respectively, have been synthesized. The molecular structures of the complexes were determined by spectrophotometric studies using ir, 1H and 13C nmr, es and mass spectrophotometry revealed that the geometries of the complexes 1, 2, 3, and 6 are tetrahedral, while 4 and 5 have square planar geometry. These geometries were supported by their magnetic moments data. The coordination of the ligands to the metal ion are through their oxygen atoms. TGA studies showed that they are thermally stable. Their antioxidant studies revealed that they are good antioxidants.

scholarly journals Preparation and Spectroscopic Studies of Some Metal Ion Complexes of 2-((4-Formyl-3-Hydroxynaphthalen-2-yl) Diazenyl) Benzoic Acid

2016 ◽  
Vol 13 (2) ◽  
pp. 95-104
Author(s):  
Baghdad Science Journal
Keyword(s):  
Benzoic Acid ◽  
Gas Phase ◽  
Metal Ion ◽  
Spectroscopic Studies ◽  
Molar Conductance ◽  
Molar Ratio ◽  
Spectral Studies ◽  
Mass Spectral ◽  
Square Planar ◽  
Ft Ir

New azo ligand 2-((4-formyl-3-hydroxynaphthalen-2-yl) diazenyl) benzoic acid (H2L) was synthesized from the reaction of 2-aminobenzoic acid and2-hydroxy-1-naphthaldehyde. Monomeric complexes of this ligand, of general formulae [MII(L)(H2O)] with (MII = Mn, Co, Ni, Cu, Zn, Pd, Cd and Hg ) were reported. The compounds were isolated and characterized in solid state by using 1H-NMR, FT-IR, UV–Vis and mass spectral studies, elemental microanalysis, metal content, magnetic moment measurements, molar conductance and chloride containing. These studies revealed tetrahedral geometries for all complexes except PdII complex is Square planar. The study of complexes formation via molar ratio of (M:L) as (1:1). Theoretical treatments of compounds in gas phase were studied using Hyper Chem-8 program has.

scholarly journals Synthesis, Characterization and Biological Activity of Schiff Bases Chelates with Mn(II),Co(II),Ni (II),Cu(II) and Hg(II)

2017 ◽  
Vol 14 (2) ◽  
pp. 390-402 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Magnetic Susceptibility ◽  
Biological Activity ◽  
Benzoic Acid ◽  
Spectral Data ◽  
Schiff Bases ◽  
Structural Features ◽  
Molar Conductance ◽  
Octahedral Geometry ◽  
Square Planar

In this paper, some series of new complexes of Mn(II), Co(II), Ni (II) Cu(II) and Hg(II) are prepared from the Schiff bases (L1,L2). (L1) derived from 4-aminoantipyrine and O-phenylene dia mine then (L2) derived from (L1) and 2-benzoyl benzoic acid. Structural features are obtained from their elemental microanalyses, molar conductance, IR, UV–Vis, 1H, 13CNMR spectra and magnetic susceptibility. The magnetic susceptibility and UV–Vis, IR spectral data of the ligand (L1) complexes get square–planar and tetrahedral geometries and the complexes oflig and (L2) get an octahedral geometry. Antimicrobial examinations show good results in the sharing complexes.

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