Quantum chemical calculations reproduced well the electronic absorption spectrum and spin Hamilto... more Quantum chemical calculations reproduced well the electronic absorption spectrum and spin Hamiltonian parameters for MnL(NCS).
Until now, the known structures of heterodinuclear Cu− Ln complexes involve compartmental Schiff-... more Until now, the known structures of heterodinuclear Cu− Ln complexes involve compartmental Schiff-base ligands with saturated diamino chains. We report here two Cu− Ln complexes (Ln= Gd or Ce) which are the first structurally characterized Cu− Ln entities ...
Several theoretical investigations with CASSCF methods confirm that the magnetic behavior of Cu-G... more Several theoretical investigations with CASSCF methods confirm that the magnetic behavior of Cu-Gd complexes can only be reproduced if the 5d Gd orbitals are included in the active space. These orbitals, expected to be unoccupied, do present a low spin density, which is mainly due to a spin polarization effect. This theory is strengthened by the experimental results reported herein. We demonstrate that Cu-Gd complexes characterized by Cu-Gd interactions through single-oxygen and three-atom bridges consisting of oxygen, carbon, and nitrogen atoms, present weak ferromagnetic exchange interactions, whereas complexes with bridges made of two atoms, such as the nitrogen-oxygen oximato bridge, are subject to weak antiferromagnetic exchange interactions. Therefore, a bridge with an odd number of atoms induces a weak ferromagnetic exchange interaction, whereas a bridge with an even number of atoms supports a weak antiferromagnetic exchange interaction, as observed in pure organic compounds and also, as in this case, in metal-organic compounds with an active spin polarization effect.
Aquation of the investigational anticancer drug trans-[Ru(III)Cl4(Hind)2](-) (1, KP1019) results ... more Aquation of the investigational anticancer drug trans-[Ru(III)Cl4(Hind)2](-) (1, KP1019) results in the formation of mer,trans-[Ru(III)Cl3(Hind)2(H2O)] (2), which was isolated in high yield (85%) and characterized by spectroscopic methods and X-ray crystallography. Dissolution of 2 in acetone, led to its dimerization into [Ru(III)2(mu-Cl)2Cl4(Hind)4] x 2 (Me)2CO (3) in 79% yield, with release of two water molecules. Complex 2 reacts readily with nucleophilic organic molecules, viz., methanol or dimethyl sulfide, at room temperature by replacement of the aqua ligand to give mer,trans-[Ru(III)Cl3(Hind)2(MeOH)] (4) and mer,trans-[Ru(III)Cl3(Hind)2(Me2S)] (5) in 58 and 64% yield, respectively. By reaction of 2 with DMSO at room temperature or dimethyl sulfide at elevated temperatures trans,trans,trans-[Ru(II)Cl2(Hind)2(Me2S)2] (6) and trans,trans,trans-[Ru(II)Cl2(Hind)2(S-DMSO)2] (7) were prepared in 64 and 75% yield, respectively. Dissolution of 2 in acetonitrile or benzonitrile gave rise to mer,trans-[Ru(III)Cl3(Hind)(HNC(Me)ind)] (8a), mer,trans-[Ru(III)Cl3(Hind)(HNC(Ph)ind)] (8b), and trans,trans-[Ru(III)Cl2(HNC(Me)ind)2]Cl (9) in 67, 50, and 23% yield, respectively, upon metal-assisted iminoacylation of indazole, which is unprecedented for ruthenium(III). Furthermore, complex 2 reacts with the DNA-model bases 9-methyladenine (9-meade) and N6,N6-dimethyladenine (6-me2ade) to yield mer,trans-[Ru(III)Cl3(Hind)2(9-meade)] (10) and mer,trans-[Ru(III)Cl3(Hind)2(6-me2ade)] (11) with the purine bases bound to the Ru(III) center via N7 and N3, respectively. Complex 11 represents the first ruthenium complex in which the coordination of the purine ligand N6,N6-dimethyladenine occurs via N3. In addition, the polymer [Na(EtOAc)2Ru(III)(mu-Cl)4(Hind)2]n (12) was crystallized from ethyl acetate/diethyl ether solutions of Na[trans-Ru(III)Cl4(Hind)2] x 1.5 H2O (1a). The reported complexes were characterized by elemental analysis, IR and UV-vis spectroscopy, ESI mass spectrometry, cyclic voltammetry, and X-ray crystallography. Electrochemical investigations give insight into the mechanistic details of the solvolytic behavior of complex 2. The lability of the aqua ligand in 2 suggests that this complex is a potential active species responsible for the high antitumor activity of trans-[Ru(III)Cl4(Hind)2](-).
ABSTRACT Five complexes [Mn2O(L1)4]n (1), [Co(L2)(H2O)2]n (2), [Co(L3)2(H2O)2]n (3) and [Co(L4)2(... more ABSTRACT Five complexes [Mn2O(L1)4]n (1), [Co(L2)(H2O)2]n (2), [Co(L3)2(H2O)2]n (3) and [Co(L4)2(4,4′-bpy)(H2O)]n (4) were obtained by using flexible organic ligands HL1, HL2, HL3, and HL4 in hydrothermal systems with cobalt, copper and manganese salts respectively (HL1=2-(4-pyridylmethylthio)benzoic acid, HL2=4-(4-pyridylmethylthio)benzoic acid, HL3=2-(3-pyridylmethylthio)benzoic acid, HL4=4-(2-pyridylmethylthio)benzoic acid). The five complexes have been characterized by X-ray single crystal diffraction, FT-IR spectrum and elemental analysis. Complex 1 is assembled to a 3D porous framework with Mn2O units as nodes. Complex 2 shows 2D layer networks comprised of six-coordinated Co2+ centers and L2− anionic ions. Complexes 3 and 4 have different 1D double or single chain structures. Various non-covalent bonds such as hydrogen bonds, π⋯π interactions, H-bond grids and S⋯S weak interactions lead to interesting supramolecular frameworks. DC (direct current) temperature dependent magnetic susceptibilities suggest weak antiferromagnetic behaviors exist in 1, and single ion paramagnetic along with spin-orbit coupling behavior dominate in 3 and 4.
A 1D heterometallic Cr2/Ag2 polymer formulated as {[Ag(μ-H2O)Ag(nta)Cr(μ-OH)(μ-AcO,O′)Cr(nta)]·H2... more A 1D heterometallic Cr2/Ag2 polymer formulated as {[Ag(μ-H2O)Ag(nta)Cr(μ-OH)(μ-AcO,O′)Cr(nta)]·H2O}n (1) (H3nta=nitrilotriacetic acid) has been prepared and structurally characterized. {Cr(μ-OH)(μ-OAc)Cr} dimeric units containing two different bridging ligands, hydroxo and acetate groups are coordinated to six Ag atoms forming the 1D network. The temperature dependence of magnetic susceptibility for 1 which was fitted with an isotropic Hamiltonian including biquadratic exchange parameters, yielded antiferromagnetic
Three mononuclear complexes, one of Cu(II) {[Cu(LA)2] (4)}, and two of Zn(II) {[Zn(LA)2] (5) and ... more Three mononuclear complexes, one of Cu(II) {[Cu(LA)2] (4)}, and two of Zn(II) {[Zn(LA)2] (5) and [Zn(LB)2(H2O)2]2+ (6)} have been synthesized through treating the corresponding metal salts with Schiff bases of trimethylsilyl-propyl-p-aminobenzoate with salicylaldehyde HLA (2) and o-vanillin HLB (3). The Schiff base ligands and their metal complexes were structurally confirmed by spectral techniques (FTIR, 1H-NMR, 13C-NMR, ESI-MS, elemental analysis) and single crystal X-ray diffraction. Crystallographic data revealed different coordination environments of the metal ions: a strict square-planar geometry of the copper ion in 4, a distorted tetrahedral geometry of the zinc ion in 5, and an usual (O6) octahedral coordination of the zinc ion in 6. Spectral analysis of optical emission indicated that Zn(II) complexes exhibit strong fluorescence properties as compared with the ligands and Cu(II) complex. Thermogravimetric analysis results suggested a lower stability of the metal complexes ...
Quantum chemical calculations reproduced well the electronic absorption spectrum and spin Hamilto... more Quantum chemical calculations reproduced well the electronic absorption spectrum and spin Hamiltonian parameters for MnL(NCS).
Until now, the known structures of heterodinuclear Cu− Ln complexes involve compartmental Schiff-... more Until now, the known structures of heterodinuclear Cu− Ln complexes involve compartmental Schiff-base ligands with saturated diamino chains. We report here two Cu− Ln complexes (Ln= Gd or Ce) which are the first structurally characterized Cu− Ln entities ...
Several theoretical investigations with CASSCF methods confirm that the magnetic behavior of Cu-G... more Several theoretical investigations with CASSCF methods confirm that the magnetic behavior of Cu-Gd complexes can only be reproduced if the 5d Gd orbitals are included in the active space. These orbitals, expected to be unoccupied, do present a low spin density, which is mainly due to a spin polarization effect. This theory is strengthened by the experimental results reported herein. We demonstrate that Cu-Gd complexes characterized by Cu-Gd interactions through single-oxygen and three-atom bridges consisting of oxygen, carbon, and nitrogen atoms, present weak ferromagnetic exchange interactions, whereas complexes with bridges made of two atoms, such as the nitrogen-oxygen oximato bridge, are subject to weak antiferromagnetic exchange interactions. Therefore, a bridge with an odd number of atoms induces a weak ferromagnetic exchange interaction, whereas a bridge with an even number of atoms supports a weak antiferromagnetic exchange interaction, as observed in pure organic compounds and also, as in this case, in metal-organic compounds with an active spin polarization effect.
Aquation of the investigational anticancer drug trans-[Ru(III)Cl4(Hind)2](-) (1, KP1019) results ... more Aquation of the investigational anticancer drug trans-[Ru(III)Cl4(Hind)2](-) (1, KP1019) results in the formation of mer,trans-[Ru(III)Cl3(Hind)2(H2O)] (2), which was isolated in high yield (85%) and characterized by spectroscopic methods and X-ray crystallography. Dissolution of 2 in acetone, led to its dimerization into [Ru(III)2(mu-Cl)2Cl4(Hind)4] x 2 (Me)2CO (3) in 79% yield, with release of two water molecules. Complex 2 reacts readily with nucleophilic organic molecules, viz., methanol or dimethyl sulfide, at room temperature by replacement of the aqua ligand to give mer,trans-[Ru(III)Cl3(Hind)2(MeOH)] (4) and mer,trans-[Ru(III)Cl3(Hind)2(Me2S)] (5) in 58 and 64% yield, respectively. By reaction of 2 with DMSO at room temperature or dimethyl sulfide at elevated temperatures trans,trans,trans-[Ru(II)Cl2(Hind)2(Me2S)2] (6) and trans,trans,trans-[Ru(II)Cl2(Hind)2(S-DMSO)2] (7) were prepared in 64 and 75% yield, respectively. Dissolution of 2 in acetonitrile or benzonitrile gave rise to mer,trans-[Ru(III)Cl3(Hind)(HNC(Me)ind)] (8a), mer,trans-[Ru(III)Cl3(Hind)(HNC(Ph)ind)] (8b), and trans,trans-[Ru(III)Cl2(HNC(Me)ind)2]Cl (9) in 67, 50, and 23% yield, respectively, upon metal-assisted iminoacylation of indazole, which is unprecedented for ruthenium(III). Furthermore, complex 2 reacts with the DNA-model bases 9-methyladenine (9-meade) and N6,N6-dimethyladenine (6-me2ade) to yield mer,trans-[Ru(III)Cl3(Hind)2(9-meade)] (10) and mer,trans-[Ru(III)Cl3(Hind)2(6-me2ade)] (11) with the purine bases bound to the Ru(III) center via N7 and N3, respectively. Complex 11 represents the first ruthenium complex in which the coordination of the purine ligand N6,N6-dimethyladenine occurs via N3. In addition, the polymer [Na(EtOAc)2Ru(III)(mu-Cl)4(Hind)2]n (12) was crystallized from ethyl acetate/diethyl ether solutions of Na[trans-Ru(III)Cl4(Hind)2] x 1.5 H2O (1a). The reported complexes were characterized by elemental analysis, IR and UV-vis spectroscopy, ESI mass spectrometry, cyclic voltammetry, and X-ray crystallography. Electrochemical investigations give insight into the mechanistic details of the solvolytic behavior of complex 2. The lability of the aqua ligand in 2 suggests that this complex is a potential active species responsible for the high antitumor activity of trans-[Ru(III)Cl4(Hind)2](-).
ABSTRACT Five complexes [Mn2O(L1)4]n (1), [Co(L2)(H2O)2]n (2), [Co(L3)2(H2O)2]n (3) and [Co(L4)2(... more ABSTRACT Five complexes [Mn2O(L1)4]n (1), [Co(L2)(H2O)2]n (2), [Co(L3)2(H2O)2]n (3) and [Co(L4)2(4,4′-bpy)(H2O)]n (4) were obtained by using flexible organic ligands HL1, HL2, HL3, and HL4 in hydrothermal systems with cobalt, copper and manganese salts respectively (HL1=2-(4-pyridylmethylthio)benzoic acid, HL2=4-(4-pyridylmethylthio)benzoic acid, HL3=2-(3-pyridylmethylthio)benzoic acid, HL4=4-(2-pyridylmethylthio)benzoic acid). The five complexes have been characterized by X-ray single crystal diffraction, FT-IR spectrum and elemental analysis. Complex 1 is assembled to a 3D porous framework with Mn2O units as nodes. Complex 2 shows 2D layer networks comprised of six-coordinated Co2+ centers and L2− anionic ions. Complexes 3 and 4 have different 1D double or single chain structures. Various non-covalent bonds such as hydrogen bonds, π⋯π interactions, H-bond grids and S⋯S weak interactions lead to interesting supramolecular frameworks. DC (direct current) temperature dependent magnetic susceptibilities suggest weak antiferromagnetic behaviors exist in 1, and single ion paramagnetic along with spin-orbit coupling behavior dominate in 3 and 4.
A 1D heterometallic Cr2/Ag2 polymer formulated as {[Ag(μ-H2O)Ag(nta)Cr(μ-OH)(μ-AcO,O′)Cr(nta)]·H2... more A 1D heterometallic Cr2/Ag2 polymer formulated as {[Ag(μ-H2O)Ag(nta)Cr(μ-OH)(μ-AcO,O′)Cr(nta)]·H2O}n (1) (H3nta=nitrilotriacetic acid) has been prepared and structurally characterized. {Cr(μ-OH)(μ-OAc)Cr} dimeric units containing two different bridging ligands, hydroxo and acetate groups are coordinated to six Ag atoms forming the 1D network. The temperature dependence of magnetic susceptibility for 1 which was fitted with an isotropic Hamiltonian including biquadratic exchange parameters, yielded antiferromagnetic
Three mononuclear complexes, one of Cu(II) {[Cu(LA)2] (4)}, and two of Zn(II) {[Zn(LA)2] (5) and ... more Three mononuclear complexes, one of Cu(II) {[Cu(LA)2] (4)}, and two of Zn(II) {[Zn(LA)2] (5) and [Zn(LB)2(H2O)2]2+ (6)} have been synthesized through treating the corresponding metal salts with Schiff bases of trimethylsilyl-propyl-p-aminobenzoate with salicylaldehyde HLA (2) and o-vanillin HLB (3). The Schiff base ligands and their metal complexes were structurally confirmed by spectral techniques (FTIR, 1H-NMR, 13C-NMR, ESI-MS, elemental analysis) and single crystal X-ray diffraction. Crystallographic data revealed different coordination environments of the metal ions: a strict square-planar geometry of the copper ion in 4, a distorted tetrahedral geometry of the zinc ion in 5, and an usual (O6) octahedral coordination of the zinc ion in 6. Spectral analysis of optical emission indicated that Zn(II) complexes exhibit strong fluorescence properties as compared with the ligands and Cu(II) complex. Thermogravimetric analysis results suggested a lower stability of the metal complexes ...
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Papers by Sergiu Shova