Ru(II) complexes imparting N<SUB>2</SUB>O<SUB>2</SUB> donor bis chelating ligand N,N′-bis(salicylidine)-hydrazine in unusual coordination mode

The synthesis and characterization of binuclear ruthenium complexes [{(η⁶-C₆H₆)Ru}₂(μ-bsh)₂](1), [{(η⁶-C₁₀H₁₄)Ru}₂(μ-bsh)₂] (2), [{(η⁶-C₆Me₆)Ru}₂(μ-bsh)₂] (3), and rhodium complex [{(η⁵-C₅Me₅)RhCl}₂(μ-bsh)] (4) (bsh=N,N^′-bis(salicylidine)-hydrazine dianion) are reported. The complexes have been fully characterized by analytical and spectral techniques and unusual coordination mode of the ligand H₂bsh has been confirmed by single crystal X-ray analysis of the complex 2. Structural data revealed extensive inter- and intra-molecular C–H⋯O and C–H⋯π interactions and involvement of methyl and isopropyl hydrogen from the p-cymene in hydrogen bonding

Ruthenium(II) polypyridyl complexes: potential precursors, metalloligands, and topo II inhibitors

Neutral and cationic mononuclear complexes containing both group 15 and polypyridyl ligands [Ru(κ³-tptz)(PPh₃)Cl₂] [1; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine], [Ru(κ³-tptz)(κ²-dppm)Cl]BF₄ [2; dppm = bis(diphenylphosphino)methane], [Ru(κ³-tptz)(PPh₃)(pa)]Cl (3; pa = phenylalanine), [Ru(κ³-tptz)(PPh₃)(dtc)]Cl (4; dtc = diethyldithiocarbamate), [Ru(κ³-tptz)(PPh₃)(SCN)₂] (5) and [Ru(κ³-tptz)(PPh₃)(N₃)₂] (6) have been synthesized. Complex 1 has been used as a metalloligand in the synthesis of homo- and heterodinuclear complexes [Cl₂(PPh₃)Ru(μ-tptz)Ru(η⁶-C₆H₆)Cl]BF₄ (7), [Cl₂(PPh₃)Ru(μ-tptz)Ru(η⁶-C₁₀H₁₄)Cl]PF₆ (8), and [Cl₂(PPh₃)Ru(μ-tptz)Rh(η⁵-C₅Me₅)Cl]BF₄ (9). Complexes 7−9 present examples of homo- and heterodinuclear complexes in which a typical organometallic moiety [(η⁶-C₆H₆)RuCl]⁺, [(η⁶-C₁₀H₁₄)RuCl]⁺, or [(η⁵-C₅Me₅)RhCl]⁺ is bonded to a ruthenium(II) polypyridine moiety. The complexes have been fully characterized by elemental analyses, fast-atom-bombardment mass spectroscopy, NMR (¹H and ³¹P), and electronic spectral studies. Molecular structures of 1−3, 8, and 9 have been determined by single-crystal X-ray diffraction analyses. Complex 1 functions as a good precursor in the synthesis of other ruthenium(II) complexes and as a metalloligand. All of the complexes under study exhibit inhibitory effects on the Topoisomerase II−DNA activity of filarial parasite Setaria cervi and β-hematin/hemozoin formation in the presence of Plasmodium yoelii lysate

Tuned helical array of Rh<SUP>III</SUP>/Ir<SUP>III</SUP> Cp* complexes with polypyridyl ligands

Reactions of the chloro-bridged dimeric complexes [{(η⁵-C₅Me₅)M(μ-Cl)Cl}₂] (M = Rh, Ir) with the polypyridyl ligands 2,3-di(2-pyridyl)pyrazine (dpp) and 2,4,6-tri(2-pyridyl)-1,3,5-triazine (tptz) in the presence of ammonium tetrafluoroborate gave the mononuclear complexes [(η⁵-C₅Me₅)MCl(κ²-dpp)]BF₄ [M = Rh (1), Ir (2)] and [(η⁵-C₅Me₅)MCl(κ²-tptz)]BF₄ [M = Rh (3), Ir (4)]. The complexes have been characterised by elemental analysis, FAB-MS, ESMS, IR, NMR, electronic and emission spectroscopic studies and the molecular structures of 1, 2 and 3 have been crystallographically determined. Structural studies on the complexes revealed the presence of helical superstructures resulting from C–H•••X (X = N, F, Cl and π) interactions

DNA-binding behavior of ruthenium(II) complexes containing both group 15 donors and 2,2′:6′,2″-terpyridine

Tetrafluoroborate salts of cationic ruthenium complexes [Ru(κ3-tpy)(EPh3)2Cl]+ (tpy=2,2′:6′,2″-terpyridine; E=P, 1 or As, 2) containing both the group 15 donor ligands and tpy and their representative substitution products are reported. Weak interaction {C–H⋯X (X=Cl, F and π) and π–π interaction} studies revealed the presence of a double helical motif in complex 1, while the complex 2 assumes a single helical motif. Intercalative mode of interaction of the complexes 1 and 2 with calf thymus DNA (ctDNA) has been supported by absorption titration studies

Synthetic, spectral and structural studies of some homo and hetero binuclear arene ruthenium (II) polypyridyl complexes

Homo-hetero binuclear cationic complexes with the formulation [(η⁶-arene)RuCl(μ-dpp)(L)]⁺ (η⁶-arene=benzene; L=PdCl₂ (1a); PtCl₂ (1b), and η⁶-arene=p-cymene; L=PdCl₂ (2a); PtCl₂ (2b)), [(η⁶-arene)RuCl(μ-dpp)(L)]²⁺(η⁶-arene=p-cymene; L=[(η⁶-C₆H₆)RuCl] (2c), and [(η⁶-C₁₀H₁₄)RuCl] (2d)) were prepared. Molecular structure of the representative homo binuclear complex [{(η⁶-C₁₀H₁₄)RuCl}(μ-dpp){(η⁶-C₁₀H₁₄)RuCl}](PF₆)₂ (2d) was determined crystallographically. Weak interaction studies on the complex 2d revealed stabilisation of the crystal packing by weak inter and intra molecular C–H⋯X (X=F, Cl, π) and π–π interactions. The C–H⋯F interactions lead to parallel helical chains and encapsulation of counter anion in self-assembled cavity arising from C–H⋯π and π–π weak interactions

Structural diversity in heteroleptic dipyrrinato copper(II) complexes

Synthesis and characterization of the heteroleptic dipyrrinato complexes [Cu2 (2-pcdpm)2 (acac)2] (1), [Cu2 (2-pcdpm)2 (hfacac)2] (2), [Cu3 (4-OHdpm)2 (acac)4] (3), [Cu3 (4-OHdpm)2 (hfacac)4] (4), [Cu2 (3-OHdpm)(acac)3] (5), [Cu2 (3-OHdpm)(hfacac)3] (6), [Cu(2-OHdpm)(acac)] (7) and [Cu(2-OHdpm)(hfacac)] (8) (acac = acetylacetone; hfacac = hexafluoroacetylacetone; 2-pcdpm = 4-(2-methoxypyridyl)phenyldipyrromethene; 3-pcdpm = 4-(3-methoxypyridyl)phenyldipyrromethene; 4-pcdpm = 4-(4-methoxypyridyl)phenyldipyrromethene; 4-/3-/2-OHdpm = 4-/3-/(2-hydroxyphenyl)dipyrromethene) have been described. The complexes 1–8 have been characterized by elemental analyses, ESI-MS, IR, UV–Vis, EPR and electrochemical (CV and DPV) studies. Electronic absorption spectra of 1–8 clearly suggested that position of the absorption bands depend on the nuclearity and coordination geometry about the copper(II) centres. Structures of 1, 2, 3 and 7 have been determined by X-ray single crystal analyses. The spectral and structural studies revealed that copper(II) in 1 and 2 adopted square pyramidal geometry, whereas in 7 a square planar geometry. On the other hand in trinuclear complex 3 one copper(II) adopted square planar, while other two square pyramidal geometry. In their cyclic voltammograms, 1–6 exhibited an irreversible oxidation and two reduction waves whereas 7 and 8 displayed one oxidation and reduction wave. Variable temperature magnetic susceptibility measurements suggested paramagnetic nature of the complexes 1–3. The X-ray photoelectron spectroscopic (XPS) studies indicated that copper(II) centres in complex 3 are present in two different coordination environments. Room temperature EPR studies on 1–8 (g|| > g⊥ &#62; 2.003) suggested a typical d9 copper(II) with unpaired electron lying in a dx2-y2 orbital

Luminescent piano-stool complexes incorporating 1-(4-cyanophenyl)imidazole: synthesis, spectral, and structural studies

Three novel luminescent piano-stool arene ruthenium complexes of general formula [(η⁶-arene)RuCl₂(CPI)] (η⁶-arene = benzene, 1, p-cymene, 2, and hexamethylbenzene, 3; CPI=1-(4-cyanophenyl)imidazole were prepared. The molecular structures of 2 and 3 were determined crystallographically. Reaction of 1−3 with EPh₃ (E = P, As, or Sb) and N−N donor bases such as 2,2‘-bipyridine and 1,10-phenanthroline afforded cationic mononuclear complexes of general formula [(η⁶-arene)RuCl(CPI)(EPh₃)]⁺ (η⁶-arene = C₆H₆, E = P (1a), E = As (1b), E = Sb (1c); η⁶-arene = C₁₀H₁₄, E = P (2a), E = As (2b), E = Sb (2c); η⁶-arene = C₆Me₆, E = P (3a), E = As (3b), E = Sb (3c)) and [(η⁶-arene)Ru(N−N)(CPI)]²⁺ (η⁶-arene = C₆H₆, N−N = bipy (1d), N−N = phen (1e); η⁶-arene = C₁₀H₁₄, N−N = bipy (2d), N−N = phen (2e); η⁶-arene = C₆Me₆, N−N = bipy (3d), N−N = phen (3e)). Molecular structures of 1a and 2a were also confirmed by X-ray crystallography. Structural studies of the complexes 2, 3, 1a, and 2a supported coordination of CPI through the imidazole nitrogen and the presence of a pendant nitrile group. Structural data also revealed stabilization of crystal packing in the complexes 2, 3, and 2a by C−H•••X (X = Cl, F) type inter- and intramolecular interactions and in complex 1a by π−π stacking. Moreover, neutral homonuclear bimetallic complexes 2f,g were prepared by using complex 2 as a metallo-ligand, where CPI acts as a bridge between two metal centers. Emission spectra of the mononuclear complexes [(η⁶-arene)RuCl₂(CPI)] and its derivatives exhibited intense luminescence when excited in the metal to ligand charge-transfer band

Ruthenium complexes containing pyridine-2-carbaldehyde azine as a synthon in the synthesis of bi-/trimetallic complexes

Ruthenium complexes [(η⁵-C₅H₅)Ru(PPh₃)(κ²-paa)]PF₆ (paa = pyridine-2-carbaldehyde azine) and [(η⁵-C₅H₅)Ru(κ¹-dppm)(κ²-paa)]BF₄ [dppm = bis(diphenylphosphanyl)methane] have been employed as a synthon in the synthesis of homo/hetero bi-/trimetallic complexes. It is the uncoordinated N,N-donor site on paa in complex [(η⁵-C₅H₅)Ru(PPh₃)(κ²-paa)]PF₆, and N,N-donor site on paa and pendant phosphorus in [(η⁵-C₅H₅)Ru(κ¹-dppm)(κ²-paa)]BF₄ that allows for their incorporation into bi-/trimetallic systems. The resulting complexes have been characterized by analytical, spectral and electrochemical studies. Molecular structures of homo-bimetallic complex [(PPh₃)(η⁵-C₅H₅)Ru(μ-paa)Ru(η⁶-C₁₀H₁₄)Cl](PF₆)₂ and hetero-bimetallic complex [(PPh₃)(η⁵-C₅H₅)Ru(μ-paa)Rh(η⁵-C₅Me₅)Cl](PF₆)₂ have been authenticated crystallographically. Complexes exhibit absorptions throughout the visible region and complicated electrochemical behaviour. Metal-based Ru^II/Ru^III oxidations in the bimetallic complexes do not vary as in the trimetallic complexes