NNN Donor Ligands Research Articles

Palladium(II) complexes comprising thiazole-hydrazone Schiff base ligand: Synthesis, structure and catalytic activity in Suzuki-Miyaura coupling reactions

Palladium(II) complexes comprising thiazole-hydrazone Schiff base ligand: Synthesis, structure and catalytic activity in Suzuki-Miyaura coupling reactions

A comprehensive study on synthesis and crystal structures of Cu(II) and Ni(II) complexes: In vitro and in silico evaluation of biomolecular interactions, antiproliferative activities and molecular docking

A comprehensive study on synthesis and crystal structures of Cu(II) and Ni(II) complexes: In vitro and in silico evaluation of biomolecular interactions, antiproliferative activities and molecular docking

Synthesis, crystal studies, antimicrobial activity, and BSA binding studies of metal complexes derived from pyridyl-based hydrazone: Multi-spectroscopic and DFT approach

Synthesis, crystal studies, antimicrobial activity, and BSA binding studies of metal complexes derived from pyridyl-based hydrazone: Multi-spectroscopic and DFT approach

Manganese(II) coordination compounds of thiazole-hydrazone based NNN-donor ligands: Synthesis, characterization and catalytic activity

• Synthesis and characterization of [Mn(L 1 ) 2 ]∙2CH 3 OH (1) and [Mn(L 2 ) 2 ] (2) where HL 1 and HL 2 are NNN-donor benzo-thiazole ligand. • Single crystal X-ray structure of two Mn(II) coordination compounds. • Investigation of the catalytic performance of 1 and 2 in olefin oxidation in the presence of TBHP or H 2 O 2 as oxidant. The reaction of Mn(OAc) 2 ∙4H 2 O with ( E )-2-(2-(pyridin-2-ylmethylene)hydrazinyl)benzo[ d ]thiazole (HL 1 ) and ( E )-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)benzo[ d ]thiazole ( HL 2 ), in methanol resulted in the formation of [Mn(L 1 ) 2 ]∙2CH 3 OH (1) and [Mn(L 2 ) 2 ] ( 2 ) as neutral mononuclear Mn(II) coordination compounds. These compounds were characterized by spectroscopic methods and their molecular structures were determined by single crystal X-ray diffraction analysis. In these compounds, the ligands are coordinated to the Mn(II) core via the nitrogen atoms of thiazole ring, pyridine ring and imine moiety and act as tridentate mononegative NNN-donor ligand. The manganese(II) coordination compounds were also used as catalyst for olefin oxidation in the presence of tert -butylhydroperoxide (TBHP) or H 2 O 2 as oxidant. Under similar experimental conditions with equal loading of Mn(II) coordination compounds, the presence of TBHP resulted in higher oxidation conversion than H 2 O 2 .

A highly selective and sensitive ratiometric fluorescent probe for quantitative detection of Al(III) in different natural matrices

A highly selective and sensitive assay of Al(III) using ratiometric fluorescence enhancement is reported in an aqueous solution. The probe (named RS5) exhibits a red-shift of 54 nm upon binding with Al(III) ion. The significant enhancement response of RS5 at 481 nm is attributed to the formation of a 1:1 complex between the probe and Al(III), wherein RS5 acts as a tridentate NNN-donor ligand. The complexation process is ascertained by 1H, 13C, and 27Al NMR and HR-MS spectral techniques. The binding constant of the complex is determined to be 1.3 × 105 M−1. The ratiometric change in fluorescence upon complexation with Al(III) is ascribed to an increase in intramolecular charge transfer (ICT) transition along with chelation enhanced fluorescence (CHEF) processes. The probe can be applied for monitoring Al(III) in a pH range of 6–8. The limit of detection (LOD) of RS5 for the examination of Al(III) is found to be 0.3 μM. With an aim to understand the sensing behavior of RS5, the optical properties of the probe and its Al(III) complex are investigated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. The probe is successfully employed for the determination of Al(III), with very high recovery percentages, in natural matrices like deep well water, tap water, drinking water, pond water, river water, bovine serum albumin (BSA) solution and blood serum.

Manganese(Ii) Coordination Compounds of Thiazole-Hydrazone Based Nnn-Donor Ligands: Synthesis, Characterization and Catalytic Activity

Manganese(Ii) Coordination Compounds of Thiazole-Hydrazone Based Nnn-Donor Ligands: Synthesis, Characterization and Catalytic Activity

Coordination of reduced Schiff base anion to Pd(II): Synthesis, characterization, DFT calculation and catecholase activity

The article reports the synthesis and characterization of a new palladium(II) complex of type [(L NNN 1− )PdCl] ( 1 ) where L NNN 1− is a mono anionic Schiff's base having a imine bond in reduced state. The L NNN 1− is generated from a tridentate NNN donor ligand (L NNN ) through in-situ reduction using sodium borohydride, where L NNN is [(E)-N-(phenyl(pyridine-2-yl)methylene)quinoline-8-amine)]. 1 is characterized by the single crystal X-ray diffraction study, IR, mass and UV–Vis spectroscopy. The X-ray bond parameter authenticates the imine bond of the coordinated Schiff's base anion is in reduced state. 1 exhibits catalytic activity towards the oxidation of 3,5-ditertiarybutyl catechol(3,5-DTBC) with turnover number (K cat ) ​= ​135.6 h -1 . The catalytic oxidation of 3,5-DTBC is authenticated by the UV–Vis, mass and EPR spectroscopy. An isotropic EPR signal with g ​= ​2.011 of a solution containing 1 and 3,5-DTBC authenticating the generation of organic radical during the oxidation process. Cyclic voltammogram of 1 displays an irreversible anodic wave at +0.22 ​V may be due to the oxidation of N − to N •− . The atomic spin density of 1 + obtained from DFT calculation is also supporting the N-centre oxidation process.

Exploring the DNA interactions, FGF growth receptor interaction and biological screening of metal(II) complexes of NNN donor ligand derived from 2‑(aminomethyl)benzimidazole

This work deals with a series of biologically important novel transition metal(II) Schiff base chelates containing terpyridine. Benzimidazole, a moiety found in broad spectrum of drugs is espoused in a Schiff base ligand system. Eight such metal(II) complexes are designed, synthesized and characterized. An octahedral geometry has been envisaged for all the complexes. DNA-binding behaviours are studied by absorption titration, electrochemical, viscosity, fluorescence and circular dichroism methods. The DNA cleavage ability is also evaluated by agarose gel electrophoresis method. These studies reveal that the complexes show an intercalative mode of binding to CT-DNA and also effectively cleave the supercoiled pBR322 DNA. The molecular docking studies of the complexes against FGF growth receptors indicate that they bind through electrostatic, van der Waals, hydrogen bonding and π-π interactions. The ligand and its complexes are screened for in vitro antimicrobial activities against a few microorganisms. The data exhibit that they are better antimicrobial agents than the ligand. The cytotoxic activity of the complexes is probed in four cell lines wherein the complex 5 has good cytotoxic activity and is partial to MCF-7 cell line which is comparable with the cisplatin drug which can be attributed to the presence of planar terpyridine co-ligand.

Synthesis, structural characterization and catalytic potential of oxidovanadium(IV) and dioxidovanadium(V) complexes with thiazole-derived NNN-donor ligand

Reaction between the tridentate NNN donor ligand, (E)-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)benzo[d]thiazole (HL), and V2O5 in ethanol gave a new vanadium(V) complex, [VO2L] (1), while the similar reaction by using [VIVO(acac)2] as the metal source gave two different types of crystals related to compounds [VO2L] (1) and [VIVO(acac)L] (2). The molecular structures of the complexes were determined by single-crystal X-ray diffraction and spectroscopic characterization was carried out by means of FT-IR, UV–vis and NMR experiments as well as elemental analysis. The oxidovanadium(IV) and dioxidovanadium(V) species were used as catalyst precursors for olefin oxidation in the presence of hydrogen peroxide (H2O2) as an oxidant. Under similar experimental conditions, the presence of 1 resulted in higher oxidation conversion than 2.

Dioxidovanadium(V) complexes containing thiazol-hydrazone NNN-donor ligands and their catalytic activity in the oxidation of olefins

Abstract The reaction between tridentate NNN donor ligands, (E)-2-(2-(pyridin-2-ylmethylene)hydrazinyl)benzo[d]thiazole (HL1) and (E)-2-(2-(phenyl(pyridin-2-yl)methylene)hydrazinyl)benzo[d]thiazole (HL2), with VO(acac)2 in ethanol gave [VO2(L1)] (1) and [VO2(L2)] (2) complexes. Complex [VO2(L2)]·0.2(H2O) (3) was produced from the reaction of HL2 and V2O5 in ethanol. Molecular structures of complexes were determined by single-crystal X-ray diffraction. All of the investigated compounds were further characterized by elemental analysis, FT-IR, UV–vis and NMR spectroscopy. The dioxidovanadium(V) species were used as catalysts for olefin oxidation in the presence of hydrogen peroxide (H2O2) as an oxidant. Under similar experimental conditions with equal vanadium loading, the presence of the [VO2(L1)] (1) resulted in higher conversion than in the case of using [VO2(L2)] (2) and [VO2(L2)]·0.2(H2O) (3) as catalytic agents.

Cationic Thorium Alkyl Complexes of Rigid NON- and NNN-Donor Ligands: π-Arene Coordination as a Persistent Structural Motif

Reaction of the neutral dialkyl complex [(XA2)Th(CH2SiMe3)2] {1; XA2 = 4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene} with [CPh3][B(C6F5)4] in benzene or toluene at room temperature resulted in the formation of [(XA2)Th(CH2SiMe3)(η6-arene)][B(C6F5)4] {arene = C6H6 (5) and toluene (5B)}, which were characterized by 1H, 13C, and 2D NMR spectroscopy and by X-ray crystallography (for 5). In close analogy, reaction of [(XA2)Th(CH2Ph)2] (3) with [CPh3][B(C6F5)4] in toluene at room temperature resulted in the formation of 1 equiv of Ph3CCH2R (R = Ph) and precipitation of an insoluble orange-brown oil, which upon layering with hexanes yielded crystals of [(XA2)Th(η2-CH2Ph)(η6-C6H5Me)][B(C6F5)4] (6). NMR investigation of the reactions of 1 and 3 with substoichiometric amounts of [CPh3][B(C6F5)4] provided no evidence for dinuclear monocation formation. By contrast, reaction of [(BDPP)Th(CH2Ph)2] {4; BDPP = 2,6-bis(2,6-diisopropylanilidomethyl)pyridine} with 0.5 equiv of [CPh3][B(C6F5)4] resulted in the precipitation of an insoluble oil containing a mixture of a mononuclear and a dinuclear cation; the dinuclear cation was identified as [(BDPP)Th(η2-CH2Ph)(μ-η1:η6-CH2Ph)Th(η1-CH2Ph)(BDPP)][B(C6F5)4] (7) by X-ray crystallography. Reaction of complex 3 with B(C6F5)3 resulted in the formation of [(XA2)Th(η1-CH2Ph)][η6-PhCH2B(C6F5)3] (9), which was characterized in solution by NMR spectroscopy. Complexes 5, 5B, and 6 are rare examples of arene solvent-separated ion pairs, complex 9 exists as a tight contact ion pair, and dinuclear 7 exhibits a unique benzyl ligand bridging mode. The structures of cations 5−7 and 9 highlight a pronounced tendency for these systems to engage in arene π-coordination.

Fac-[Re(CO)3L] Complexes Containing Tridentate Monoanionic Ligands (L−) Having a Terminal Amido and Two Amine Ligating Groups

Treatment of fac-[Re(CO)3(H2O)3]+ with two unsymmetrical tridentate NNN donor ligands (LH) based on a diethylenetriamine (dien) moiety with a 2,4,6-trimethylbenzoyl (tmbCO) group linked to a terminal nitrogen of dien through an amide produced the neutral complexes [Re(CO)3(tmbCO-N,N-Me2dien)] and [Re(CO)3(tmbCO-dien)]. The [Re(CO)3(tmbCO-N,N-Me2dien)] complex crystallized in the space group P21/c, a = 19.5793 (15), b = 7.4239 (5), c = 14.8071 (10) A, β = 104.425(5)°, V = 2084.4(3) A3, and the [Re(CO)3(tmbCO-dien)] complex crystallized in the space group C2/c, a = 36.861 (7), b = 7.3990 (10), c = 14.933 (3) A, β = 102.145 (8)°, V = 3981.6(12) A3. X-ray crystallographic and NMR analyses confirm that in both the solid and solution states the ligands are bound to the fac-Re(CO)3 core in a tridentate fashion with the amide group being deprotonated. An important property in radiopharmaceuticals is shape, which in turn depends on ring pucker. For [Re(CO)3(tmbCO-N,N-Me2dien)], the two chelate rings have different pucker chirality, as is commonly found for a broad range of metal complexes. However, for fac-[Re(CO)3(tmbCO-dien)], the two chelate rings have the same pucker chirality, a finding attributable to two strong intermolecular hydrogen bonds from the NH2 to two waters of crystallization. Impeded by methyl group clashes with chelate ring hydrogens, the tmb ring rotation about the C(amido)–C(tmb) bond is slow on the NMR time scale. fac -[Re(CO) 3 L] Complexes Containing Tridentate Monoanionic Ligands (L − ) Having a Terminal Amido and Two Amine Ligating Groups Anna Maria Chirstoforou, Patricia A. Marzilli, Frank R. Fronczek, and Luigi G. Marzilli X-ray crystallographic and NMR analyses of fac-Re(CO)3 complexes containing diethylenetriamine-based, NNN tridentate ligands with a terminal deprotonated amido donor group allow comparison to previously reported analogues with a terminal deprotonated sulfonamido donor group.

Fac-Re(CO)3L Complexes Containing Tridentate Monoanionic Ligands (L-) with a Seldom-Studied Sulfonamido Group As One Terminal Ligating Group

To achieve a net-neutral coordination unit in radiopharmaceuticals with a fac-M(CO)3+ core (M = Tc, Re), facially coordinated monoanionic tridentate ligands are needed. New neutral fac-Re(CO)3L complexes were obtained by treating fac-[Re(CO)3(H2O)3]+ with unsymmetrical tridentate NNN donor ligands (LH) based primarily on a diethylenetriamine (dien) moiety with an aromatic group linked to a terminal nitrogen through a sulfonamide. LHs contain 2,4,6-trimethylbenzenesulfonyl (tmbSO2) and 5-(dimethylamino)naphthalene-1-sulfonyl (DNS) groups. X-ray crystallographic and NMR analyses confirm that in both the solid and the solution states all L- in fac-Re(CO)3L complexes are bound in a tridentate fashion with one donor being nitrogen from a deprotonated sulfonamido group. Another fundamental property that is important in radiopharmaceuticals is shape, which in turn depends on ring pucker. For L- = tmbSO2-dien-, tmbSO2-N'-Medien-, and tmbSO2-N,N-Me2dien-, the two chelate rings have a different pucker chirality, as is commonly found for a broad range of metal complexes. However, for fac-Re(CO)3(DNS-dien), both chelate rings have the same pucker chirality because the sulfonamido ring has an unusual pucker for the absolute configuration at Re; a finding that is attributable to intramolecular and intermolecular hydrogen bonds from the sulfonamido oxygens to the NH2 groups. Averaging of tmb NMR signals, even at -90 degrees C for Re(CO)3(tmbSO2-N,N-Me2dien), indicates rapid dynamic motion in the complexes with this group. However, examination of the structures suggests that free rotation about the S-C(tmb) bond is not possible but that concerted coupled rotations about the N-S and the S-C bonds can explain the NMR data.

2,6-Diacetylpyridinebis(p-methoxyaniline), a TerdentateNNNDonor Ligand

The title compound, C 23 H 23 N 3 0 2 , is a terdentate NNN donor ligand. The molecule lies about a crystallographic mirror plane which passes through a C and an N atom of the substituted pyridine ring. The orientation of the exocyclic N atoms in the solid is not what is required for complex formation with metal centres.

Studies of phosphazenes. Part 34. Group 6 metal carbonyl complexes of bis(pyrazolyl)cyclotriphosphazenes

Reactions of the bis(3,5-dimethylpyrazol-1-yl)cyclotriphosphazenes gem-N3P3Ph4(C3HN2Me2)2 (L1) and N3P3(MeNCH2CH2O)2(C3HN2Me2)2 (L2) with [M(CO)6] (M = Mo or W) afford complexes of the type [M(CO)3L] (L = L1 or L2), which have been characterised by IR and NMR spectroscopic data. The structures of [Mo(CO)3L1], [W(CO)3L2] and the ligand L2 have been determined by single-crystal X-ray diffraction. The phosphazenes act as novel tridentate NNN-donor ligands with two pyrazolyl nitrogen atoms and one phosphazene ring nitrogen atom bonded to the metal atom

Ir(I) complexes with chiral terdentate NNN donor ligands: Very effective and selective catalysts in hydrogen transfer reactions

Ir(I) complexes with chiral terdentate NNN donor ligands: Very effective and selective catalysts in hydrogen transfer reactions

Coordination compounds of 2,6-diacetylpyridinedihydrazone-II. Preparation and characterization of the complexes with heavier lanthanide chlorides, perchlorates and nitrates

Abstract The Tb, Dy, Ho, Er, Tm, Yb and Lu (Ln) complexes of 2,6-diacetylpyridine-dihydrazone (L) with chlorides, perchlorates and nitrates as counterions have been prepared and characterized by spectral data, thermal and elemental analysis. They are formulated as [LnL2(H2O)2)]Cl3·2H2O, [LnL2(H2O)2]·(ClO4)3·2H2O and [LnL(NO3)3(H2O)2]·2H2O. The hydrazone acts as a terdentate NNN donor ligand and the nitrates appear to coordinate in the monodentate fashion.

Characterization of metal complexes of 2,6-diacetylpyridinebis(imines). Preparation and crystal structure of tetrafluoroborato-2,2?-bipyridyl{2,6-bis[1-(p-ethylphenylimino)ethyl]pyridine}-copper(II) tetrafluoroborate

X-ray analysis has established the “semicoordination” bonding mode for one tetrafluoroborate anion in tetrafluoroborato-2,2′-bipyridyl{2,6-bis[1-(p-ethylphenylimino)ethyl]pyridine}copper(II) tetrafluoroborate, [Cu(bipy) (C25H27N3)(FBF3)]BF4. Crystals of the title compound are monoclinic, space group P21/n with four molecules in the unit cell ofa=14.991(3),b=14.989(3),c=16.933(4) A,β=109.33(2)°. The structure was solved by the heavy-atom method and refined by blocked full-matrix least squares calculations with anisotropic thermal parameters for nonhydrogen atoms toR=0.049 andR w=0.051 for 3311 reflections withI>3σ(I). The copper atom coordination is pseudo-octahedral, with one nitrogen atom of the bipyridyl ligand [Cu-N(2)1.985(4) A] and three nitrogen atoms of the terdentate NNN donor ligand [Cu-N(3) 1.923(4), Cu-N(4) 2.073(4), Cu-N(5) 2.073(4) A] forming the equatorial plane. The axial sites are occupied by the second nitrogen atom of the bipyridyl ligand [Cu-N(1) 2.186(5) A] and a loosely bound fluorine atom [Cu-F(21) 2.692(5) A] of the “semicoordinated” tetrafluoroborate group. The other BF 4 − anion is ionic. Electronic and vibrational spectral data for the complex are discussed in terms of the geometry of the cation.

Synthesis and characterization of metal complexes of terdentate NNN donor ligands derived from 2,6-diacetylpyridine. Nickel(II), copper(II), zinc(II) and cadmium(II) complexes of 2,6-diacetylpyridinebis(anil) with both monodentate and bidentate nitrate groups

Abstract Some divalent metal complexes of 2,6-diacetylpyridinebis(anil), a terdentate NNN donor ligand, having a variety of nitrato bonding modes are reported. The complexes of the type ML(NO 3 ) 2 , MLCl(NO 3 ), [ML(en)NO 3 ]NO 3 and [ML 2 ](NO 3 ) 2 (M = Ni(II), Cu(II), Zn(II) and Cd(II); L = C 21 H 19 N 3 ; en = ethylenediamine) are characterized by magnetic moment, conductivity, and NMR, infrared, Raman and electronic spectral measurements. The spectral data is correlated with the metal geometry and the type of nitrato coordination, which includes ionic, monodentate, bidentate, as well as both monodentate and bidentate simultaneously.

Synthesis and characterization of metal complexes of terdentate NNN donor.txt ligands derived fromo 2,6-diacetylpyridine. Nickel(II) complexes with 2,6-diacetylpyridinebis(imines)

Abstract The synthesis and characterization of fourteen 1:1 and 1:2 nickel(II) complexes of some 2,6-diacetylpyridinebis(imines) are reported. The coordinating ability of these terdentate NNN donor ligands is comparable to that of terpyridine and is virtually independent of the amine substituent. The complexes NiX 2 ·L are pentacoordinate for X = Cl, Br, I but apparently octahedral via bridging anions for X = NCS, N 3 . The 1:1 cyano derivative of the anil ligand adopts a dimeric [NiL 2 ][Ni(CN) 4 ] structure. The seven 1:2 complexes are of the type [NiL 2 ]Y 2 (Y = Br, I, BF 4 ] involving an octahedral cation.