Paddlewheel-type and half-paddlewheel-type diruthenium(II,II) complexes with 1,8-naphthyridine-2-carboxylate.

Paddlewheel-type diruthenium(II,II) complexes are paramagnetic with two unpaired electrons ( = 1) and can be utilized as versatile building blocks for higher-order structures, such as supramolecular complexes, coordination polymers, and metal-organic frameworks, although they are generally highly air-sensitive. In this study, we developed an air-stable paddlewheel-type diruthenium(II,II) complex with two electron-withdrawing 1,8-naphthyridine-2-carboxylate (npc) ligands, [Ru(μ-npc)(OCMe)] (1). The two acetate ligands in 1 can be replaced by other carboxylate ligands; the solvothermal reactions of 1 with benzoic acid (HOCPh) yields the heteroleptic [Ru(μ-npc)(OCPh)] (2), whereas its reaction with 1,8-naphthyridine-2-carboxylic acid (Hnpc) produces the homoleptic [Ru(μ-npc)(η-npc)] (3).

Luminescent Iridium-Terpyridine Complexes with Various Bis-Cyclometalated Ligands.

A series of luminescent bis-cyclometalated iridium complexes with 2,2':6',2″-terpyridine (tpy), [Ir()(tpy)]PF ( = 2-phenylpyridinate (ppy) for ; benzo[h]quinolinate (bzq) for ; 1-phenylisoquinolinate (piq) for ; and 2-phenylbenzothiazolate (pbt) for ), have been synthesized and structurally characterized. Single-crystal X-ray diffraction analyses reveal that the tpy ligands of - are coordinated to the iridium center in a bidentate fashion, and the uncoordinated pendant pyridine rings in the tpy ligands of - form intramolecular π-π stacking interactions with a phenyl moiety of ligands. In addition, the pendant pyridine ring in the tpy ligand of forms an intramolecular hydrogen bonding interaction, unlike in -.

Hydroxypyridinate-bridged paddlewheel-type dirhodium complex as a catalyst for photochemical and electrochemical hydrogen evolution.

Electrochemical and photochemical hydrogen (H2) evolution activities of a 6-fluoro-2-hydroxypyridinate (fhp-)-bridged paddlewheel-type dirhodium (Rh2) complex, [Rh2(fhp)4], were investigated through experimental and theoretical approaches. In DMF, the [Rh2(fhp)4] underwent a one-electron reduction (assigned to Rh24+/3+) at -1.31 V vs SCE in the cathodic region.

Synthesis, Duplex-Forming Ability, and Nuclease Resistance of Oligonucleotides Containing a Thymidine Derivative with a 1-Oxaspiro[4.5]decane Skeleton.

Chemically modified nucleic acids are essential for the therapeutic application of oligonucleotides. In this study, 6'-C-spiro-thymidine exhibiting a fixed torsion angle γ was designed, synthesized, and incorporated into oligonucleotides. The conformational analysis of the 6'-C-spiro-thymidine monomer revealed that its torsion angle γ was in the +synclinal range (approx.

Redox-triggered reversible modulation of intense near-infrared and visible absorption using a paddlewheel-type diruthenium(III) complex.

A new paddlewheel-type diruthenium complex with 2-amino-3-(trifluoromethyl)pyridine (amtfmp) [Ru2(amtfmp)4Cl2] ([1]), which shows intense and characteristic near-infrared (NIR) and visible absorption, has been developed and structurally characterized by single crystal X-ray diffraction (SCXRD) analyses. This complex exhibits reversible and dramatic NIR and visible electrochromic behavior from deep-blue ([1]) to pink ([1]-) due to the ON-OFF switching of its characteristic ligand-to-metal charge transfer (LMCT) and d-d absorption bands in response to an external voltage or chemical reagent such as decamethylcobaltocene (CoCp*2). The one-electron reduced species of [1], i.

Unique vapochromism of a paddlewheel-type dirhodium complex accompanied by dynamic structural and phase transitions.

The one-dimensional coordination polymer [Rh2(HA)4]n (1G; HA = hexanoate) exhibits a drastic vapochromic color change from green to red upon exposure to pyridine (py) vapor. Heating the red discrete complex [Rh2(HA)4(py)2] (1R) at 338 K affords the purple discrete tetrarhodium complex [Rh2(HA)4(py)]2 (1P), which is an intermediate species in the vapochromic transformation of 1G to 1R. The obtained complexes 1G, 1R, and 1P differ not only in their color in the solid state, but also in their temperature-dependent phase transition properties.

Specific Coordination between Zr-MOF and Phosphate-Terminated DNA Coupled with Strand Displacement for the Construction of Reusable and Ultrasensitive Aptasensor.

Electrochemical aptasensors involved in chemical labeling are often single-use and sensitivity-limited because the probes are commonly single-point labeled and irreversible. In this work, the specific coordination between Zr and phosphate group (-PO) was employed to construct a new aptasensor that is highly sensitive and reusable, using Ochratoxin A (OTA) as the test model. The OTA binding aptamer (OBA) was hybridized with the thiolated supporting sequence (TSS) immobilized on the surface of a gold electrode.

Photocatalytic Hydrogen Evolution over Exfoliated Rh-Doped Titanate Nanosheets.

Various amounts of Rh-doped titanate nanosheets (TiNS:Rh(), where is doped amount) were prepared to develop a new nanostructured photocatalyst based on metal oxide compounds that can split water to produce H under sunlight. TiNS:Rh() was obtained by acid exchange, intercalation, and exfoliation of Rh-doped layered sodium titanate compound (NaTi Rh O). A new energy gap was found in the diffuse reflection spectrum of the TiNS:Rh() colloidal suspension solution; this new energy gap corresponds to electrons in the 4d level of Rh or Rh, which are doped in the Ti site.

Paddlewheel-type diruthenium(iii,iii) tetrakis(2-aminopyridinate) complexes with NIR absorption features: combined experimental and theoretical study.

The reactions of [Ru(OCCH)Cl] with 2-aminopyridine (Hamp) and 2-amino-4-methylpyridine (Hammp) afforded two novel Ru complexes, [Ru(amp)Cl] (1) and [Ru(ammp)Cl] (2), respectively. Single crystal X-ray diffraction analyses revealed that 1 and 2 adopted typical paddlewheel-type structures, where the Ru units are coordinated with four aminopyridinate ligands with a cis-2:2 arrangement at the equatorial positions and two chloride ligands at the axial positions. The stabilities of 1 and 2 were supported by unrestricted density functional theory (uDFT) calculations.

Intrinsic hydrogen evolution capability and a theoretically supported reaction mechanism of a paddlewheel-type dirhodium complex.

The intrinsic capability of the paddlewheel-type dirhodium tetraacetate complex, [Rh(OCCH)(HO)] ([1(HO)]), as a hydrogen evolution catalyst (HEC) for photochemical hydrogen evolution from aqueous solution was illustrated. This was achieved by using an optimized artificial photosynthesis (AP) system with a cyclometalated iridium complex [Ir(ppy)(bpy)](PF) ([Ir-PS-1]) and triethylamine (TEA) serving as a photosensitizer (PS) and a sacrificial donor, respectively. The total amount of hydrogen evolution and the turnover number (TON) of catalysis using this AP system were 385.

Synthesis, Characterization, Absorption Properties, and Electronic Structures of Paddlewheel-Type Dirhodium(II) Tetra-μ-(-naphthoate) Complexes: An Experimental and Theoretical Study.

The reactions of [Rh₂(O₂CCH₃)₄(OH₂)₂] with -naphthalenecarboxylic acids ( = 1: 1-HNC, = 2: 2-HNC) afford the dirhodium tetra-μ-(-naphthoate) complexes [Rh₂(1-NC)₄] () and [Rh₂(2-NC)₄] (), respectively. Single crystal X-ray diffraction analyses of [1(OCMe₂)₂] and [2(OCMe₂)₂], which were obtained by recrystallization from acetone (OCMe₂) solutions of and , reveal that the dirhodium cores are coordinated by four equatorially bridging naphthoate ligands and two axial OCMe₂ ligands. Density functional theory (DFT) calculation confirmed that (i) the single Rh⁻Rh bond is formed between the two Rh ions and (ii) the electronic structures between two Rh ions in and are best described as π⁴δ²σ²δ*²π*⁴ and δ²π⁴σ²δ*²π*⁴, respectively.

Experimental and theoretical study of dimer-of-dimers-type tetrarhodium(ii) complexes bridged by 1,4-benzenedicarboxylate linkers.

Two dimer-of-dimers-type tetrarhodium complexes, [Rh4(piv)6(BDC)] ([1]; piv = pivalate) and [Rh4(piv)6(F4BDC)] ([2]), in which two paddlewheel-type dirhodium units are linked by 1,4-benzenedicarboxylate (BDC) and 1,4-tetrafluorobenzenedicarboxylate (F4BDC), respectively, have been synthesized and characterized via single-crystal X-ray diffraction analyses, ESI-MS, 1H NMR, infrared spectroscopy, Raman spectroscopy, and elemental analyses. Crystal structure analyses of [1(THF)4] and [2(THF)4], which are crystallized from THF solutions of [1] and [2], respectively, revealed that dihedral angles (φ) between two -CO2 units and phenyl rings of the BDC linker in [1(THF)4] are almost co-planar (φ = 2.8°), whereas those of the F4BDC linker in [2(THF)4] are largely inclined (φ = 78.