Molecular Self-Assembly in a Family of Oxo-Bridged Dinuclear Ruthenium(IV) Systems

Abstract

A series of six novel RuIV compounds of formula (H2bpy)2­[{RuCl5}2(μ-O)] (1), (PPh4)2[{RuCl4­(H2O)}2(μ-O)]·4H2O (2), (PPh4)2­[{RuCl4­(MeCN)}2(μ-O)] (3), (PPh4)2­[{RuCl4(dmf)}2(μ-O)] (4), (PPh4)2­[{RuCl4(py)}2(μ-O)] (5), and [{RuCl3­(bpym)}2(μ-O)]·6H2O (6) [H2bpy2+ = 4,4′-bipyridine-1,1′-diium cation; PPh4 + = tetraphenylphosphonium cation; dmf = N,N′-dimethylformamide; py = pyridine; bpym = 2,2′-bipyrimidine] have been prepared and spectroscopically, electrochemically, and magnetically characterized. Compounds 1, 2, 5, and 6 crystallize in the triclinic system with space group P1̅, whereas 3 and 4 crystallize in the monoclinic system with space group P21/c. While 1–5 are salts based on anionic dinuclear RuIV species, 6 is a neutral diruthenium­(IV) complex. The Ru–O–Ru core is present in 1–6 [with values of the Ru–Ooxo bond length covering the range of 1.774(1)–1.816(1) Å and the values of the Ru–O–Ru angle (θ) varying in the range of 164.3–180.0°]. In their crystal lattice, intermolecular RuIV–Cl···Cl–RuIV halogen bonds (1 and 6), Cl···π (1 and 3–6), and π···π (5 and 6) type interactions as well as hydrogen bonds (1, 2, and 6) are present. These intermolecular interactions generate novel supramolecular structures based on the self-assembly of (μ-oxo)­diruthenium­(IV) complexes. Magnetic susceptibility measurements performed on microcrystalline samples of 1–6 confirmed the diamagnetic nature for the six compounds, which are strongly antiferromagnetically coupled. The study of the electrochemical properties of 2–6 through cyclic voltammetry (CV) in dmf allowed us to evaluate the effect of the ligand nature on the rich redox features along this series of (μ-oxo)­diruthenium­(IV) complexes.

Detection of Hypoxanthine from Inosine and Unusual Hydrolysis of Immunosuppressive Drug Azathioprine through the Formation of a Diruthenium(III) System

“…In the dinuclear complex of 1a and 1b , each six-coordinate Ru III ion is bonded to four chloride ions and two nitrogen atoms (N3 and N9) from two hpx molecules in a distorted octahedral environment. No significant differences are found in the Ru–Cl [average value, 2.329(1) Å in 1a and 2.310(1) Å in 1b ] and Ru–N [2.066(1) Å in 1a and 2.061(1) Å in 1b ] bond lengths, which are similar in both compounds and are in agreement with those values found in previously reported Ru III systems [ 40 , 41 ]. The two Ru III ions are linked each other through two hpx molecules and a double Ru–Cl–Ru bridge and the short intramolecular Ru···Ru distance that is generated (ca.…”

A Gadolinium(III) Complex Based on the Thymine Nucleobase with Properties Suitable for Magnetic Resonance Imaging

“…To overcome limitations related to the size of atoms, a normalized contact distance (d norm ) was also considered [29,30]. For compound 1, Hirshfeld surfaces are shown in Figure 4 and Figure S6, where the shorter contacts are displayed using red color [31]. Intermolecular O•••H contacts between water molecules and between water molecules and carbonyl groups of the thymine molecules are the main interactions detected on the Hirshfeld surface (Figure 4 and Figure S6).…”

Ferromagnetic Coupling and Single-Ion Magnet Phenomenon in Mononuclear Ruthenium(Iii) Complexes Based on Guanine Nucleobase

“…The surfaces were drawn considering the distances from a point on the surface to the nearest atom outside (de) and inside (di) their surfaces. Any restriction associated to the size of the involved atoms was corrected through a normalized distance, named dnorm, which was analyzed as previously done [18][19][20]. The Hirshfeld surfaces, along with their fingerprint maps, for complexes 1 and 2 are given in Figures 4 and 5, respectively.…”

“…All the synthesis were carried out under aerobic conditions, by using reagents as received. The ruthenium precursor (PPh4)2[{RuCl4(H2O)}2(µ-O)]•4H2O was obtained following the synthetic method previously described in the literature [18]. SEM-EDX analyses were obtained through a Hitachi S-4800 field emission scanning electron microscope, and elemental analyses (C, H, N) were performed by the Central Service for the Support to Experimental Research (SCSIE) at the University of Valencia.…”