Cobalt(III) complexes, of two potentially pyrazole-derived bidentate ligands (with one ambidentate donor site), 3,5-dimethyl-1-(N-methyl/ethyl)thiocarbamylpyrazole (HL 1 for N-methyl, HL 2 for N-ethyl) have been synthesized and characterized by elemental analyses, IR, UV-Vis and 1 H NMR spectral studies. The structure of Co(L 2 ) 3 has been determined by single-crystal X-ray diffraction studies. The complex (triclinic, space group P1) has a distorted octahedral structure with the ambidentate ligands coordinated to the Co(III) ion as uninegative bidentate chelating agents via the pyrazole ring nitrogen (tertiary) and the thiocarbamyl iminyl nitrogen atoms. The distortion from the regular octahedral geometry is ascribed to the stereochemical limitations imposed by the planar bidentate ligands. © 2000 Elsevier Science B.V.

A K BARIK

S PAUL

R J BUTCHER

S K KAR

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Synthesis and characterization of two tris-chelate complexes of cobalt(III) with 3,5-dimethyl-1-(N-methyl/ethyl)thiocarbamylpyrazole (HL1, HL2) — biologically important bidentate ligands with one ambidentate donor site

Polyhedron

Trinuclear mixed oxidation state Co(III/II/III) complexes with a different coordination geometry at each cobalt center of a pyrazole derived Schiff base and mononuclear cobalt (III) complexes of another pyrazole containing Schiff base having N-donor atoms have been prepared and structurally characterized. Reaction of 5-methyl-3-formylpyrazole (MPA) and 1,3-diamino-2-propanol (DAP) with CoX2 · 6H2O (X = Cl, Br) in a 2:1:1 ratio produces unusual trinuclear mixed-valent complexes [Co3(L1)2Cl4] (1) and [Co3(L1)2Br4] (2) [where H2L1 = 1, 3-bis(5-methyl-3-formylpyrazolylmethinimino)propane-2-ol], and the same reaction when carried out with CoX2 · 6H2O (X = CH3 COO-,ClO4-NO3-, BF4-) produces mononuclear [Co(L1)(H2O)2]X · H2O, of which only [Co(L1)(H2O)2]CH3COO · H2O (3) was isolated. In contrast, the reaction of 5-methyl-3-formylpyrazole (MPA) and 1,3-diamino-2-propanol (DAP) with CoX2 · 6H2O (where X = ClO4-NO3-, BF4-) in a 1:1:1 ratio produces mononuclear Schiff base complexes [Co(L)2] ClO4 (4), [Co(L)2] NO3 (5) and [Co(L)2] BF4 (6) [where HL = 1-(5-methyl-3-formylpyrazolylmethinimino)-3-aminopropane-2-ol], whereas when X = Cl and Br a hygroscopic intractable material was isolated. Among the above species, 1 and 4 have been crystallographically characterized. In 1, three cobalt atoms are arranged in a linear fashion and are bridged through pyrazolate rings. The terminal diamagnetic low spin cobalt(III) ions with a N4Cl2 chromophore are in a distorted octahedral environment. These two outer cobalt(III) complexes individually act as bidentate chelating ligands and encapsulate the central cobalt(II) ion, which adopts a distorted flattened, tetrahedral geometry with a N4 chromophore. The interatomic separations are 3.794 Å (Co1⋯Co2) and 3.791 Å (Co2⋯Co3). In 4, the cobalt(III) atom is also in a distorted octahedral geometry with a N6 chromophore. Variable temperature (300-2 K) magnetic susceptibility measurements have been carried out for 1 and 2. Zero field splitting of the tetrahedral cobalt(II) ion has been noticed. The EPR spectrum of 1 and 2 at low temperature is associated with a Kramer doublet ±1/2 arising from the S = 3/2 ground state. Some of the complexes are further characterized by UV-Vis, IR and electrochemical studies. The IR spectrum of 3 shows the typical vibration of ionic acetate at 1577 cm-1 (νasym) and 1397 cm-1 (νsym). © 2007 Elsevier Ltd. All rights reserved.

Anion dependent formation of linear trinuclear mixed valance cobalt(III/II/III) complexes and mononuclear cobalt(III) complexes of a pyrazole derived ligand - Synthesis, characterization and X-ray structures

The solid complexes of Cu (II) with different counterions and Ni (II) having no counterions with 3 5-dimethyl-1-N-methyl thiocarbamylpyrazole (HL1) and 3 5-dimethyl-1-N-ethyl thiocarbamylpyrazole (HL2)the ligands having coordination function of the pyrazole ring and the thiocarbamido group have been prepared and their geometries established on the basis of molar conductance magnetic susceptibility IR UV and visible spectral data Magnetic and spectral features indicate paramagnetic [Cu (HL1/HL2)X2] (X = Cl Br) [Cu (HL1/HL2)2] (ClO4)2 as either planar or tetragonally distorted octahedral species with the ligands in the neutral thione form while Ni (L1/L2)2 as the diamagnetic square planar species with the ligands in the deprotonated thiol form X-ray crystallographic studies of Ni (L2)2 has unambiguously proved the distorted square planar environment around the central nickel (II) ion the ligand molecules are cis-coordinated to the nickel (II) ion © 1998 Elsevier Science Ltd All rights reserved.

Copper (II) and nickel (II) complexes of pyrazole derived ligands: Synthesis, characterization and coordinating properties of two substituted thiocarbamyl pyrazoles, 3,5-dimethyl-1-N-methyl/ethyl thiocarbamyl pyrazole (HL1, HL2), potential ligands for bio

The coordination mode of the title ligand, HMPzSB (synthesized for the first time and characterised by elemental analysis, mass, IR and PMR spectral parameters), is reported by solid state isolation and physicochemical identification of cobalt(III) complexes, [Co(MPzSB)2]X (X = Cl, ClO4 and BF4). Electronic spectral features of these diamagnetic CoIII species classify them as six-coordinate distorted octahedral ones. IR spectra (4000-200 cm-1) of HMPzSB and its complexes are indicative of an uninegative tridentate NNS function of the title ligand through the Pyrazolyl (2N) nitrogen, azomethine nitrogen and thiolato sulphur atom. 1H-NMR data (in d6-DMSO at 300 MHz) of the uncomplexed ligand and its CoIII species are commensurate with the tridenticity (NNS) of the deprotonated form of HMPzSB. X-ray crystallographic studies of [Co(MPzSB)2]Cl has authenticated that the geometry of the species is distorted octahedral, as envisaged, with the two deprotonated primary ligand systems (MPzSB-). The Co - N (azomethine) and Co - N (pyrazolyl) bond lengths are 1.898(4) &amp; 1.954(5) Å and 1.903(4) &amp; 1.916(5) Å in ligand A &amp; B, respectively where as that of Co - S (thiolato) is 2.217(2) and 2.255(2) Å in the two ligands. The extended planarity of the dithiocarbazate moiety and the pyrazolyl ring of the primary ligand system are maintained because of the ligation phenomenon to CoIII. © 1997 Elsevier Science Ltd.

Synthesis and spectroscopic characterisation of cobalt(III) complexes with S-benzyl dithiocarbazate of 5-methyl-3-formyl pyrazole (HMPzSB) : X-ray crystal structure of [Co(MPzSB)2]Cl

Synthesis and spectroscopic characterization of nickel(II) complexes with5-methyl-3-formylpyrazole-N(4)-methylthiosemicarbazone (HL4Me): X-ray crystallographic studies of[Ni(HL4Me)2](NO3)·22H2O

Inorganica Chimica Acta

Cobalt(III) complexes with 2-acetyl- and 2-formylpyridine 4N-methylthiosemicarbazones

Chemical Reviews

Recent advances in poly(pyrazolyl)borate (scorpionate) chemistry

Synthesis and characterization of two tris-chelate complexes of cobalt(III) with 3,5-dimethyl-1-(N-methyl/ethyl)thiocarbamylpyrazole (HL 1 , HL 2 ) - Biologically important bidentate ligands with one ambidentate donor site

Journal	Data powered by TypesetPolyhedron
Publisher	Data powered by TypesetElsevier Ltd
ISSN	0277-5387