Reaction Of H2L Research Articles

Synthesis, characterization of indol-2-yl-based NCO pincer rare-earth metal alkyl complexes and their catalytic activity towards hydroboration of imines

The reactions of HL (L = 1-(CH3OCH2CH2)-3-(Me2NCH2)-C8H4N) with different equivalent of the RE(CH2SiMe3)3(THF)2 produced a series of novel indol-2-yl-based NCO pincer rare-earth metal dialkyl complexes (κ3NCO-L)RE(CH2SiMe3)2 (RE = Lu(1a), Yb(1b)) and monoalkyl complexes (κ2NC-L)(κ3NCO-L)RE(CH2SiMe3) (RE = Lu(2a), Yb(2b), Er(2c), Y(2d)). These complexes served as catalysts for the hydroboration of imines and exhibited excellent activity with high efficiency under solvent-free and ambient temperature conditions.

Synthesis of chiral Cu(II) complexes from pro-chiral Schiff base ligand and investigation of their catalytic activity in the asymmetric synthesis of 1,2,3-triazoles

A pro-chiral Schiff base ligand (HL) was synthesized by the reaction of 2-amino-2-ethyl-1,3-propanediol and pyridine-2-carbaldehyde in methanol. The reaction of HL with CuCl2·2H2O and CuBr2 in methanol gave neutral mononuclear Cu(II) complexes with general formula of [Cu(HL)Cl2] (1) and [Cu(HL)Br2] (2), respectively. By slow evaporation of the methanolic solutions of 1 and 2, their enantiomers were isolated in crystalline format. The formation of pure chiral crystals in the racemic mixture was amply authenticated by single crystal X-ray analysis, which indicated that S-[Cu(HL)Cl2], R-[Cu(HL)Cl2], and S-[Cu(HL)Br2] are crystallized in chiral P212121 space group of orthorhombic system. Preferential crystallization was used to isolate the R and S enantiomers as single crystals and the isolated compounds were also studied by CD analysis. Structural studies indicated that the origin of the chirality in these compounds is related to the coordination mode of the employed pro-chiral ligand (HL) because one of its carbon atoms has been converted to a chiral center in the synthesized complexes. Subsequently, these complexes were used in click synthesis of a β-hydroxy-1,2,3-triazole and the results of catalytic studies indicated that 1 and 2 can act as enantioselective catalysts for the asymmetric synthesis of β-hydroxy-1,2,3-triazole product under mild condition. This study illustrates the significant capacity of the use of pro-chiral ligands in preparing chiral catalysts based on complexes which can also be considered as an effective approach to cheap chiral catalysts from achiral reagents.

Synthesis, characterization, crystal structures and biological activity of 4-chloro-2-(2-hydroxy-3-ethoxybenzylideneamino)phenol and complexes

Molecular nanoclusters comprising a heterometallic 3d-4f stoichiometry are an interesting class of compounds. In this paper, a chloro-containing Schiff base 4-chloro-2-(2-hydroxy-3-ethoxybenzylideneamino)phenol (H2L) was prepared by condensation reaction of 3-ethoxysalicylaldehyde with 2-amino-4-chlorophenol in methanol. The Schiff base is predisposed to chelate within a cluster core both 3d and 4f metal ions. Reaction of H2L with nickel salts afforded a tetranuclear NiII complex [Ni4L4(MeOH)4] (1), while with nickel salts and lanthanide(III) nitrate three tetranuclear NiII-LnIII complexes [Ni2Eu2L4(NO3)2(DMF)2] (2), [Ni2Er2L4(NO3)2(DMF)2] (3), [Ni2Tb2L4(CH3COO)2(DMF)2]·4DMF (4) were obtained. H2L and the complexes have been characterized by elemental analysis, IR, UV–Vis spectra. H2L has also been characterized by 1H and 13C NMR spectra. Molecular structures of the compounds have been determined by single crystal X-ray determination. In the complexes, the Schiff base ligands coordinate to the metal atoms via ether oxygen, imino nitrogen and two phenolate oxygen atoms. All the Ni atoms in the complexes are in octahedral coordination. The rare earth metal atoms are eight coordinated by the phenolate and ether oxygen of the Schiff base ligands, and anionic and solvent oxygen atoms, forming square antiprismatic coordination. The compounds were evaluated for their antibacterial activities on Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas fluorescens, and antifungal activities on Candida albicans and Aspergillus niger, and gave interesting results.

An efficient copper(II) salamo-based complex fluorescence chemosensor for detecting sulfide ions: Structure exploration and practical application

A novel salamo-based fluorescent chemical sensor l-Cu2+ was designed and prepared via the reaction of H2L and Cu(OAc)2·H2O. The whole research has found that Cu(II) atom in the complex crystal are located in the N2O2 cavity of H2L, forming a four-coordination system. Hirshfeld surface analysis confirmed the presence of hydrogen bonding and π···π stacking interactions. As a probe molecule, l-Cu2+can selectively and sensitively detect S2- without interference from other ions, and can be effectively used within the biological pH range. In addition, DFT theoretical calculations and molecular electrostatic potential analysis (ESP) were used to investigate the electron cloud density and positive and negative electrostatic potentials inside the probe, as well as the mechanism for identifying sulfur ions. Finally, the probe l-Cu2+has shown good practical application effects and can recognize S2− in three different water samples. It can also be used as a qualitative detection strip. l-Cu2+complex possesses excellent application prospect in bacteriostasis.

Two isostructural Zn/Co-MOFs with penetrating structures: multifunctional properties of both luminescence sensing and conversion of CO2 into cyclic carbonates.

Two new metal-organic frameworks (MOFs), namely, {[Zn(HL)(bpea)]·DMF}n (Zn-MOF-1) and {[Co(HL)(bpea)]·DMF}n (Co-MOF-2) (H3L = 3-(3,5-dicarboxybenzyloxy)benzoic acid, bpea = 1,2-di(pyridyl)ethane), were obtained by the reaction of H3L and N-containing ligand bpea with Zn(NO3)2·6H2O and Co(NO3)2·6H2O, respectively. The isomorphic Zn-MOF-1 and Co-MOF-2 featured a 3D penetrating framework with different stabilities, luminescence, and catalytic properties. Luminescence measurement indicated that Zn-MOF-1 could be used to detect Al3+ through a turn-on effect with a detection limit of 0.42 μM. The sensing mechanism experiments showed that the enhanced luminescence of Zn-MOF-1 toward Al3+ may be due to the weak interaction between Al3+ and Zn-MOF-1 and the absorbance-caused enhancement (ACE) mechanism. Meanwhile, both Zn-MOF-1 and Co-MOF-2 showed interesting CO2 adsorption properties and could catalyze the cycloaddition of CO2 to epoxides resulting in 96 and 92% ideal products within 12 hours, respectively. They can be cycled up to 5 times without significant loss of catalytic efficiency.

Crystal structure and Hirshfeld-surface analysis of di-aqua-bis-(5-methyl-1H-1,2,4-triazole-3-carboxyl-ato)copper(II).

The title compound, [Cu(HL)2(H2O)2] or [Cu(C4H4N3O2)2(H2O)2], is a mononuclear octa-hedral CuII complex based on 5-methyl-1H-1,2,4-triazole-3-carb-oxy-lic acid (H2 L). [Cu(HL)2(H2O)2] was synthesized by reaction of H2 L with copper(II) nitrate hexa-hydrate (2:1 stoichiometric ratio) in water under ambient conditions to produce clear light-blue crystals. The central Cu atom exhibits an N2O4 coordination environment in an elongated octa-hedral geometry provided by two bidentate HL - anions in the equatorial plane and two water mol-ecules in the axial positions. Hirshfeld surface analysis revealed that the most important contributions to the surface contacts are from H⋯O/O⋯H (33.1%), H⋯H (29.5%) and H⋯N/N⋯H (19.3%) inter-actions.

Investigating two structurally different penta-coordinated trigonal bipyramidal Co(II) non-symmetric salamo-type complexes

A new non-symmetric salamo-type multidentate chelating ligand H2L (4-Formyl-6ʹ-methoxyl-2,2ʹ-[ethylenedioxybis(nitrilomethylidyne)]diphenol) was designed and prepared. Two Co(II) complexes with different structures, [Co(L)(H2O)] (1) and [Co2(L)2]2·3CH3CN·2CH3OH (2) were prepared by the reactions of H2L with two different Co(II) salts (Co(OAc)2·4H2O/CoCl2·6H2O) in various organic solvents at an ambient temperature, respectively. Due to varying degrees of distortion of the ligand during the coordination reactions, the bonding modes of the ligand in complexes 1 and 2 are different. Complex 1 forms a penta-coordinated mononuclear, and complex 2 forms a penta-coordinated binuclear structure. By comparing UV–Vis and infrared spectroscopy of H2L with those of the corresponding complexes further characterize coordination between the ligand H2L and Co(II) ions. Theoretical calculations of DFT, BVS (Valence Bonding and Calculation), and IRI (Interaction Region Indicator) were used to show the different forces present in complexes 1 and 2, and BVS calculations confirmed that Co is ‘+2′ valence in the complexes. Fluorescence property studies indicated that the possible mechanism for the decrease in fluorescence intensity upon binding of H2L to Co(II) ions is chelation fluorescence quenching.

Octalithium, Tetrasodium, and Decalithium Compounds Based on Pyrrolyl Ligands: Synthesis, Structures, and Activation of the C-H Bonds of Pyrrolyl Rings and C═N Bonds of a Series of Ligands by Organolithium Reagents.

The organometallic compounds of lithium ions have garnered continuous interest as indispensable precursors for the syntheses of organometallic complexes of main-group metals, transition metals, lanthanide metals, and actinide metals. In this work, we present a strategy for the preparation of a series of polynuclear lithium complexes. This methodology features the utilization of organolithium reagents both as metal sources to coordinate with the ligands and as nucleophilic reagents to undergo nucleophilic addition to the C═N bonds of the ligands. Reaction of a ligand HL1 [HL1 = 2-(((1-(2-(dimethylamino)ethyl)-1H-pyrrol-2-yl)methylene)amino)phenol] with n-BuLi produced complex [Li8(L1a)4]·1.5Tol (1·1.5Tol) [H2L1a = 2-((1-(1-(2-(dimethylamino)ethyl)-1H-pyrrol-2-yl)pentyl)amino)phenol]. One prominent feature regarding the formation of 1·1.5Tol is the occurrence of nucleophilic addition of n-BuLi to the C═N bond of HL1, leading to the generation of a new [L1a]2- ligand that contains both aminophenol and 1-(2-pyrrolyl)alkylamine scaffolds. The developed protocol can be adapted to a series of organolithium reagents. Compounds [Li8(L1b)4] (2) and [Li8(L1c)4] (3) were afforded by treatment of HL1 with sec-BuLi and LiCH2SiMe3, respectively. Reaction of an analogous ligand HL2 [HL2 = 2-(((1-(2-(dimethylamino)ethyl)-1H-pyrrol-2-yl)methylene)amino)-4-methylphenol] with n-BuLi generated compound [Li8(L2a)4] (4). C═N bond activation was not observed in the reaction of HL1 with NaOtBu, and the complex [Na4(L1)4]·Tol (5·Tol) was obtained. A decanuclear complex [Li10(L3a)2(L3b)2] (6) was also prepared via the reaction of HL3 [HL3 = 2-(2-((((1H-pyrrol-2-yl)methylene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine] with t-BuLi. A remarkable feature in terms of the synthesis of 6 is the simultaneous occurrence of hydrogen atom abstraction from the C-H bond of the pyrrolyl ring and nucleophilic addition to the C═N bond of the HL3 ligand by t-BuLi. A series of amines containing biologically and physiologically important moieties were achieved by hydrolysis of the crude products from the reactions of the HL1-HL3 ligands and organolithium reagents. This work provides an efficient approach to high-nuclearity lithium compounds as well as a series of amines.

Cobalt(II), nickel(II), palladium(II) and zinc(II) metallothiosemicarbazones: Synthesis, characterization, X-ray structures and biological activity

Metal(II) complexes of the type [Co(S-HL)2Cl2] and [Ni(N,S-L)2], [Pd(N,S-L)2], [Zn(N,S-L)2], were synthesized from the reaction of HL with metal(II) chlorides. All complexes were characterized by spectroscopic methods, such as elemental analysis, FT-IR, 1H NMR, and single crystal X-ray diffraction. In the [Co(S-HL)2Cl2] complex, the cobalt atom adopts a distorted tetrahedral geometry around the cobalt(II) ion, with two neutral monodentate S-thiosemicarbazone ligands coordinating via one of the thiocarbonyl sulfur atom and two chlorides. In the [Ni(N,S-L)2] and [Pd(N,S-L)2] complexes, HL ligand is coordinated with the metal center, as a mono anionic bidentate N,S donors which are in trans position and that metal(II) ions adopt square planar coordination. [Zn(N,S-L)2] indicates that the anionic thiosemicarbazone ligands bind to the metal in a distorted tetrahedral arrangement with N,S donor atoms. The antimicrobial activity of the ligand and metal(II) complexes were studied against bacterial strains and fungal stain. It was observed that the ligand showed weaker activity than the metal complexes. The Zn(II) complex had the best antibacterial activity against E. faecalis, while the Co(II) complex showed the best activity against S. aureus bacteria. Co(II) and Pd(II) complexes were relatively more effective against Gram-negative bacteria. It was determined that metal complexes were less effective against gram negative bacteria compared to gram positive bacteria. A little antifungal activity was observed in Zn(II) and Co(II) complexes.

SYNTHESIS, CHARACTERIZATION AND X-RAY CRYSTAL STRUCTURES OF N'-(3,5-DIFLUORO-2-HYDROXYBENZYLIDENE)-4-METHYLBENZOHYDRAZIDE AND ITS OXIDOVANADIUM(V) COMPLEX WITH ANTIBACTERIAL ACTIVITY

A new aroylhydrazone compound N'-(3,5-difluoro-2-hydroxybenzylidene)-4-methylbenzohydrazide (H2L) was prepared. The compound was characterized by IR, UV-Vis, 1H and 13C NMR spectra, as well as single crystal X-ray diffraction. Reaction of H2L with VO(acac)2 afforded a new oxidovanadium(V) complex [VO2L(OCH3)(CH3OH)], which was characterized by IR and UV-Vis spectra, and single crystal X-ray diffraction. The V atom in the complex is in octahedral coordination. The compounds were studied on their antibacterial activities on Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescens. The results indicated that both H2L and the oxidovanadium complex have interesting antibacterial activities. The complex has strong activity against B. subtilis (2.3 μg·mL–1) and medium activity against S. aureus (9.4 μg·mL–1).

Yttrium and Lithium Complexes with Diamidophosphane Ligand Bearing 2,1,3-Benzothiazolyl Substituent: Polydentate Complexation and Reversible NH–PH Tautomery

Deprotonation of a bis(amino)phosphane H2L = PhP(HNBtd)2 bearing a heterocyclic Btd = 2,1,3-benzothiadiazol-4-yl substituents at nitrogen atoms by silylamides LiNTms2 and Y(NTms2)3 (Tms = trimethylsilylamide) results in lithium and yttrium complexes with the deprotonated HL– and L2– forms as κ2-N and κ4-N chelating ligands. A binuclear complex [LiHL]2 was crystallized from Et2O, and was shown to reversibly dissociate in thf (tetrahydrofuran) with the NH(soln)–PH(crystal) tautomeric shift; the compound [Li2L] was spectroscopically characterized. Yttrium readily forms stable bis-ligand complexes [YL2]– and [YL(HL)]. In the latter, the H atom in HL resides on phosphorus; the coordination sphere remains accessible to another ligands, and it was crystallized as [{YL(HL)}2(µ-dioxane)] species (YN8O coordination). In the former complex, the coordination sphere was saturated (YN8) by closer bound ligands; it was crystallized as a salt with [Li(thf)4]+. The monoligand complex could not be cleanly obtained in a 1:1 reaction of H2L and Y(NTms2)3, and was only crystallographically characterized as a dimer [YL(NTms)2]2. Partial oxidation of the central P atom with the formation of phosphine-oxide ligands PhP(O)(NBtd)2– was observed. They co-crystallize in the same position as non-oxidized ligands in [YL2]– and [YL(NTms2)]2 species and participate in bonding between two units in the latter. TD-DFT calculations reveal that main transitions in the visible region of electronic spectra correspond to the charge transfer bands mostly associated with the orbitals located on Btd fragments.

Synthesis and Characterization of Rare-Earth Metal Complexes Bearing a 2-N,N-Dimethylamino-Ethylene-Imino-Functionalized Indolyl Ligand and Their Catalytic Activities Toward Hydrosilylation of Imines

The reactions of 2-N,N-dimethylamino-ethylene-imino-functionalized indolyl proligand 2-(Me2NCH2CH2N = CH)C8H5NH (HL) with [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 in toluene afforded a series of rare-earth metal amido complexes [κ3-(N,N,N)-2-(Me2NCH2CH2N = CH)C8H5N]RE[N(SiMe3)2]2 (RE = Y (1a), Nd (1b), Sm (1c), Gd (1d), Dy (1e), Er (1f), and Yb (1g)). While the reaction of HL with [(Me3Si)2N]3Eu(μ-Cl)Li(THF)3 produced the europium(II) complex in a dimeric form [{(η5-μ-η1:η1:η1)-2-(Me2NCH2CH2N═CH)C8H5N}Eu{N(SiMe3)2}]2 (2), which is believed to have happened through the homolysis of the Eu–N bond. Further reaction of complex 1a with PhCH═NPh provided an unexpected rare-earth metal complex [κ2-(N,N)-PhN{PhCH(CH2SiMe2)}N(SiMe3)]YL (7) through the sp3 C–H bond activation of the methyl on the silicon atom to form a Y–C bond followed by the insertion of the C═N bond of the imine PhCH═NPh to form an amido group connected to the central metal. All complexes were characterized by spectroscopic methods, elemental analyses, and single-crystal X-ray diffraction, and complexes 1a–1c and 7 were additionally characterized by NMR spectroscopy. The catalytic performance of complexes 1a–1g for the hydrosilylation of imines was investigated, and the catalytic mechanism was proposed based on the experimental results.

Two luminescent lanthanide metal–organic frameworks as bifunctional fluorescent probes for Fe3+ and MnO4− ions

Two new Ln-MOFs, namely {[Ln(L)3]·DMF}n (Ln = Tb (1), Eu (2); HL = 4-pyridin-4-yl-benzoic acid), have been constructed by the reaction of HL, and Ln(OH)3 under solvothermal conditions. 1 and 2 are isomorphic and feature two-dimension frameworks with [Ln(COO)2]n chains. Notably, both 1 and 2 demonstrate high thermal stability and good luminescence. Furthermore, 1 and 2 can act as multi-responsive fluorescent probes for Fe3+ and MnO4− ions. The detection limits are 6.97, 7.06 and 2.77, 3.53 μM for 1 and 2, respectively, and the quenching constants (Ksv) are 8.01 × 103, 1.21 × 104 and 1.07 × 104, 1.43 × 104 M−1 for 1 and 2, respectively.

Zinc(II) and copper(II) complexes with benzothiadiazole Schiff-base ligands

The ligand (2-[4-(2,1,3-benzothiadiazole)imino]methyl-phenol) HL1 containing the electron poor benzothiadiazole (BTD) unit, conveniently prepared by condensation of 4-amino-2,1,3-benzothiadiazole and salicylaldehyde, has been structurally characterized by single crystal X-ray diffraction. Two energy minima have been determined, by DFT calculations, for HL1 and for its ortho-vanillin analogue HL2, corresponding either to the conformer observed in the solid state or to the chelating tridentate form. TD-DFT calculations have been performed on HL1 and HL2 in order to assign their experimental UV–visible absorption bands. Reaction of HL1 and HL2 with copper (II) hexafluoroacetylacetonate (hfac), zinc (II) hexafluoroacetylacetonate or zinc (II) acetate provided the neutral complexes [Cu(L1)(hfac)] (1), [Zn(L1)2] (2), [Cu(L2)2] (3) and [Zn(L2)2] (4) which were structurally characterized, with a focus on the coordination sphere of the metal centre and on the intermolecular interactions. The UV–visible absorption properties of the Zn(II) complexes 2 and 4 have been experimentally and theoretically investigated and compared to those of the ligands. Finally, the cryomagnetic study of 1 and 3 in the temperature range 2.0–295.0 K reveals a Curie-Weiss law behaviour with very weak intermolecular antiferromagnetic interactions in the low temperature region.

Synthesis, crystal structures and biological activity of trinuclear nickel(II) and copper(II) complexes derived from N,N'-bis(4-bromosalicylidene)-1,3-pentanediamine

The self-assembly reaction of the bis-Schiff base N,N'-bis(4-Bromosalicylidene)-1,3-pentanediamine (H2L) with nickel chloride and sodium azide in methanol afforded a new phenolate and end-on azide bridged trinuclear nickel complex [Ni3L2(μ1,1-N3)2(CH3OH)2]2CH3OH (1). The reaction of H2L with copper acetate produced a new phenolate and acetate bridged trinuclear copper complex [Cu3L2(CH3COO)2] (2). The complexes were characterized by elemental analysis, IR and UV-Vis spectroscopy. The crystal structures of the complexes have been determined by X-ray crystallography. In complex 1, the Ni atoms are in octahedral coordination, while in complex 2, the Cu atoms are in square pyramidal and octahedral coordination. The Schiff base ligand coordinates to the metal atoms through the two phenolate O and two imine N atoms. The antimicrobial activities of the complexes were assayed and evaluated.

SYTHESIS OF RUTHENIUM(II) COMPLEXES WITH CARBOXAMIDE DERIVATIVES: SPECTROSCOPIC CHARACTERISATION AND STUDIES ON DNA AND BSA INTERACTION

Two new mononuclear ruthenium(II) complexes of two new carboxamide derivatives formulated as [Ru(bpy)2(L7 )](ClO4)2 (1) and [Ru(bpy)2(L8 )](ClO4)2 have been isolated as pure materials from the reaction of HL 7 and HL 8 [where HL 7= N-(furan-2-ylmethyl)-2 pyridinecarboxamide and HL 8 = N-(thiophen-2-ylmethyl)-2- pyridinecarboxamide] with Ru(bpy)2Cl2. All the complexes were characterized by physico-chemical and spectroscopic tools. The interaction of the complexes with calf thymus DNA (CT-DNA) using absorption, emission spectral and viscosity studies have been used to determine the binding constant, Kb and the linear Stern-Volmer quenching constant, KSV. The results indicate that the ruthenium(II) complexes interact with CT-DNA strongly in a groove binding mode. The interactions of bovine serum albumin (BSA) with the complexes were also investigated with the help of absorption spectroscopy tools. Absorption spectroscopy proved the formation of a ground state BSA- [Ru(L)(bpy)2](ClO4)2 complex.

Synthesis and characterization of Ti(IV), Zr(IV) and Al(III) salen-based complexes

New Ti(IV), Zr(IV) and Al(III) salen-based complexes of formulae [(L)TiCl2], 2, [(L)ZrCl2], 3, and [(L){Al(CH2CH(CH3)2)2}2], 4, where L = meso-(R,S)-diphenylethylene-salen, were synthesized in high yields. [(L){Al(CH2CH(CH3)2)2}2] is a bimetallic complex that results from the reaction of H2L with either 1 or 2 equivalent of Al(CH2CH(CH3)2)3. The solid-state molecular structures of compounds 2 and 4·(C7H8) were obtained by single-crystal X-ray diffraction. Crystal data for C44H54Cl2N2O2Ti, (2a): monoclinic, space group C2/c (no. 15), a = 27.384(1) Å, b = 12.1436(8) Å, c = 28.773(2) Å, β = 112.644(2)°, V = 8830.6(9) Å3, Z = 8, μ(MoKα) = 0.350 mm-1, Dcalc = 1.146 g/cm3, 26647 reflections measured (5.204° ≤ 2Θ ≤ 50.7°), 8072 unique (Rint = 0.0967, Rsigma = 0.1241) which were used in all calculations. The final R1 was 0.0640 (I > 2σ(I)) and wR2 was 0.1907 (all data). Crystal data for C62H72Cl2N2O2Ti (2b): monoclinic, space group P21/c (no. 14), a = 19.606(1) Å, b = 12.793(1) Å, c = 23.189(2) Å, β = 105.710(4)°, V = 5599.0(7) Å3, Z = 4, μ(MoKα) = 0.291 mm-1, Dcalc = 1.182 g/cm3, 37593 reflections measured (3.65° ≤ 2Θ ≤ 50.928°), 10304 unique (Rint = 0.0866, Rsigma = 0.1032) which were used in all calculations. The final R1 was 0.0593 (I > 2σ(I)) and wR2 was 0.1501 (all data). Crystal data for C67H97Al2N2O2 (4·(C7H8)): triclinic, space group P-1 (no. 2), a = 10.0619(9) Å, b = 16.612(2) Å, c = 21.308(2) Å, α = 67.193(5)°, β = 78.157(6)°, γ = 77.576(5)°, V = 3176.8(6) Å3, Z = 2, μ(MoKα) = 0.088 mm-1, Dcalc = 1.063 g/cm3, 42107 reflections measured (5.382° ≤ 2Θ ≤ 51.624°), 12111 unique (Rint = 0.0624, Rsigma = 0.0706) which were used in all calculations. The final R1 was 0.0568 (I > 2σ(I)) and wR2 was 0.1611 (all data). The solid-state molecular structure of [(L){Al(CH2CH(CH3)2)2}2] reveals that both metal centres display a slightly distorted tetrahedral geometry bridged by the salen ligand. Both [(L)TiCl2] and [(L)ZrCl2] complexes display octahedral geometry with trans-chlorido ligands.

Nucleophilic Addition and α-C–H Substitution Reactions of an Imine Mediated by Dibutylmagnesium and Organolithium Reagents

A series of nucleophilic addition reactions and α-C–H substitution reactions of an imine-containing ligand 2-(2-((((1H-pyrrol-2-yl)methylene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine (HL1) were reported. The reactions of HL1 with 0.5 and 2 equiv of nBu2Mg, respectively, gave two complexes of compositions [Mg(L1)2] (1) and [Mg2(L2)2] (2) (H2L2 = N-((1-(2-(dimethylamino)ethyl)-1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)pentan-1-amine). The nucleophilic addition of nBu2Mg to the C═N bond of the HL1 ligand occurred in the process for the formation of 2. Treatment of HL1 with 2 and 1 equiv of nBuLi generated [Li2(L3)2] (3) (HL3 = 2-(2-(((1-(1H-pyrrol-2-yl)pentylidene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine) and [Li2(L1)2] (4). An α-C–H substitution of the HC═NR moiety of the HL1 ligand triggered by nBuLi was discovered in the preparation of 3. The formation of 3 demonstrates a new concept for the C–C coupling that involved inert C–H bond activation of HC═NR skeleton. The reactions of HL1 with MeLi, sec-BuLi, and tert-BuLi, respectively, were also examined. The products for both the nucleophilic addition of organolithium reagents to the C═N bond and α-C–H substitution of the HC═NR moiety of the HL1 ligand were determined. The mechanisms for the formations of 2 and 3 were rationalized by DFT calculations. The hydroboration reactions catalyzed by 2 were investigated, and these reactions characterize ample substrate scope, very good yields, and high selectivity.

Synthesis and structural characterization of N‐methylanthraniloyl‐ (4‐ethylthiosemicarbazide) and its Cu(II) trinuclear complex

AbstractThe new ligand N‐methylanthraniloyl(4‐ethylthiosemicarbazide) H2L was synthesized by the treatment of anthranilic acid hydrazide and ethyl isothiocyanate in absolute ethanol. The composition and structure of H2L were characterized by spectroscopic methods such as ESI MS, IR, 1H and 13C{1H} NMR spectroscopy as well as SCXRD. Reaction of H2L and mixture of [Cu(MeCN)4](PF6) and o‐phenanthroline in methanol gave rise to a cationic Cu(II) trinuclear complex, which could be separated as PF6– salt with the composition of [Cu3(L)2(o‐phen)2](PF6)2. The spectroscopic and X‐ray crystallographic data analyses demonstrated that H2L deprotonates hydrazide protons and the resulting dianion {L2–} acts as bridging ligand of which most potential donor atoms form stable chelates with Cu(II) ions. In particular, the central Cu(II) ion coordinates with two dianions {L2–} via (O, N2) donor sets, thereby adopting a distorted square planar coordination mode with trans configuration. While each of two terminal Cu(II) ions is five‐coordinate with the coordination sphere composed of (S, N1, Namine) and (N,N) donor sets belonging {L2–} and o‐phenanthroline, respectively.

A new palladium(II) phosphino complex with ONS donor Schiff base ligand: Synthesis, characterization and catalytic activity towards Suzuki-Miyaura cross-coupling reaction

New palladium(II) phosphino complex, [Pd(PPh3)(L)](ClO4) (1) with thioether containing ONS donor Schiff base ligand (HL) is synthesized by the reaction of HL with sodium tetrachloropalladate (Na2PdCl4) and PPh3. The complex is thoroughly characterized by several spectroscopic techniques. The square planar geometry of the complex is confirmed by single crystal X-ray crystallography. Cyclic voltammetric study in acetonitrile exhibits ligand based irreversible oxidation and reduction peaks at +1.18 V and -1.25 V respectively versus Ag/AgCl reference electrode. Electronic structure and UV-vis spectrum of the complex are interpreted by DFT and TDDFT calculations. Catalytic property of the complex towards Suzuki-Miyaura cross coupling reactions is explored and excellent catalytic conversions (86-97%) are observed with various substituted aryl halides and phenylboronic acid at 100 °C.