Can Non‐Kramers TmIII Mononuclear Molecules be Single‐Molecule Magnets (SMMs)?

In recent years, plentiful lanthanide‐based (Tb^III, Dy^III, and Er^III) single‐molecule magnets (SMMs) were studied, while examples of other lanthanides, for example, Tm^III are still unknown. Herein, for the first time, we show that by rationally manipulating the coordination sphere, two thulium compounds, 1 [(Tp)Tm(COT)] and 2 [(Tp*)Tm(COT)] (Tp=hydrotris(1‐pyrazolyl)borate; COT=cyclooctatetraenide; Tp*=hydrotris(3,5‐dimethyl‐1‐pyrazolyl)borate), can adopt the structure of non‐Kramers SMMs and exhibit their behaviors. Dynamic magnetic studies indicated that both compounds showed slow magnetic relaxation under dc field and a relatively high effective energy barrier (111 K for 1 , 46 K for 2 ). Magnetic diluted 1 a [(Tp)Tm_0.05Y_0.95(COT)] and 2 a [(Tp*)Tm_0.05Y_0.95(COT)] even exhibited magnetic relaxation under zero dc field. Relativistic ab initio calculations combined with single‐crystal angular‐resolved magnetometry measurements revealed the strong easy axis anisotropy and nearly degenerated ground doublet states. The comparison of 1 and 2 highlights the importance of local symmetry for obtaining Tm SMMs.     

Insight into D6h Symmetry: Targeting Strong Axiality in Stable Dysprosium(III) Hexagonal Bipyramidal Single‐Ion Magnets

Following a novel synthetic strategy where the strong uniaxial ligand field generated by the Ph₃SiO^? (Ph₃SiO^?=anion of triphenylsilanol) and the 2,4‐di‐^tBu‐PhO^? (2,4‐di‐^tBu‐PhO^?=anion of 2,4‐di‐tertbutylphenol) ligands combined with the weak equatorial field of the ligand L^N6 , leads to [Dy^III(L^N6)(2,4‐di‐^tBu‐PhO)₂](PF₆) ( 1 ), [Dy^III(L^N6)(Ph₃SiO)₂](PF₆) ( 2 ) and [Dy^III(L^N6)(Ph₃SiO)₂](BPh₄) ( 3 ) hexagonal bipyramidal dysprosium(III) single‐molecule magnets (SMMs) with high anisotropy barriers of U_eff=973 K for 1 , U_eff=1080 K for 2 and U_eff=1124 K for 3 under zero applied dc field. Ab initio calculations predict that the dominant magnetization reversal barrier of these complexes expands up to the 3rd Kramers doublet, thus revealing for the first time the exceptional uniaxial magnetic anisotropy that even the six equatorial donor atoms fail to negate, opening up the possibility to other higher‐order symmetry SMMs.     

Trinuclear [CoIII2–LnIII] (Ln=Tb,Dy) Single‐Ion Magnets with Mixed 6‐Chloro‐2‐Hydroxypyridine and Schiff Base Ligands

The Schiff base ligand N1,N3‐bis(3‐methoxysalicylidene)diethylenetriamine (H₂valdien) and the co‐ligand 6‐chloro‐2‐hydroxypyridine (Hchp) were used to construct two 3d–4f heterometallic single‐ion magnets [Co₂Dy(valdien)₂(OCH₃)₂(chp)₂] ? ClO₄ ? 5 H₂O ( 1 ) and [Co₂Tb(valdien)₂(OCH₃)₂(chp)₂] ? ClO₄ ? 2 H₂O ? CH₃OH ( 2 ). The two trinuclear [Co^III₂Ln^III] complexes behave as a mononuclear Ln^III magnetic system because of the presence of two diamagnetic cobalt(III) ions. Complex 1 has a molecular symmetry center, and it crystallizes in the C2/c space group, whereas complex 2 shows a lower molecular symmetry and crystallizes in the P2₁/c space group. Magnetic investigations indicated that both complexes are field‐induced single‐ion magnets, and the Co^III₂–Dy^III complex possesses a larger energy barrier [74.1(4.2) K] than the Co^III₂–Tb^III complex [32.3(2.6) K].     

Enhancement of TbIII–CuII Single‐Molecule Magnet Performance through Structural Modification

We report a series of 3d–4f complexes {Ln₂Cu₃(H₃L)₂X_n} (X=OAc^?, Ln=Gd, Tb or X=NO₃^?, Ln=Gd, Tb, Dy, Ho, Er) using the 2,2′‐(propane‐1,3‐diyldiimino)bis[2‐(hydroxylmethyl)propane‐1,3‐diol] (H₆L) pro‐ligand. All complexes, except that in which Ln=Gd, show slow magnetic relaxation in zero applied dc field. A remarkable improvement of the energy barrier to reorientation of the magnetisation in the {Tb₂Cu₃(H₃L)₂X_n} complexes is seen by changing the auxiliary ligands (X=OAc^? for NO₃^?). This leads to the largest reported relaxation barrier in zero applied dc field for a Tb/Cu‐based single‐molecule magnet. Ab initio CASSCF calculations performed on mononuclear Tb^III models are employed to understand the increase in energy barrier and the calculations suggest that the difference stems from a change in the Tb^III coordination environment (C_4v versus C_s).     

Magnetic Properties of Two New Fe4 Single‐Molecule Magnets in the Solid State and in Frozen Solution

Two novel tetranuclear, star‐shaped iron(III) clusters, [Fe₄(acac)₆(Br‐mp)₂] and [Fe^III₄(acac)₆(tmp)₂], are described. Both have S=5 ground states resulting from antiferromagnetic nearest‐neighbour superexchange interactions, with J=?8.2 cm^?1 and J=?8.5 cm^?1 for 1 and 2 , respectively. Energy barriers for the relaxation of the magnetisation of approximately 12 cm^?1 were derived from AC susceptibility measurements. Magnetic resonance measurements revealed a zero‐field splitting parameter D=?0.34 cm^?1 for both complexes. AC susceptibility measurements in solution demonstrated that the complexes are reasonably stable in solution. Interestingly, the magnetisation relaxation slows down significantly in frozen solution, in contrast to what is generally observed for single‐molecule magnets. This was shown to result from a large increase in τ₀, the prefactor in the Arrhenius equation, with the energy barrier remaining unchanged.     

The Frontier of Molecular Spintronics Based on Multiple‐Decker Phthalocyaninato TbIII Single‐Molecule Magnets

Ever since the first example of a double‐decker complex (SnPc₂) was discovered in 1936, MPc₂ complexes with π systems and chemical and physical stabilities have been used as components in molecular electronic devices. More recently, in 2003, TbPc₂ complexes were shown to be single‐molecule magnets (SMMs), and researchers have utilized their quantum tunneling of the magnetization (QTM) and magnetic relaxation behavior in spintronic devices. Herein, recent developments in Ln^III‐Pc‐based multiple‐decker SMMs on surfaces for molecular spintronic devices are presented. In this account, we discuss how dinuclear Tb^III‐Pc multiple‐decker complexes can be used to elucidate the relationship between magnetic dipole interactions and SMM properties, because these complexes contain two TbPc₂ units in one molecule and their intramolecular Tb^III?Tb^III distances can be controlled by changing the number of stacks. Next, we focus on the switching of the Kondo signal of Tb^III‐Pc‐based multiple‐decker SMMs that are adsorbed onto surfaces, their characterization using STM and STS, and the relationship between the molecular structure, the electronic structure, and the Kondo resonance of Tb^III‐Pc multiple‐decker complexes.

     

A Trinuclear Radical‐Bridged Lanthanide Single‐Molecule Magnet

Assembly of the triangular, organic radical‐bridged complexes Cp*₆Ln₃(μ₃‐HAN) (Cp*=pentamethylcyclopentadienyl; Ln=Gd, Tb, Dy; HAN=hexaazatrinaphthylene) proceeds through the reaction of Cp*₂Ln(BPh₄) with HAN under strongly reducing conditions. Significantly, magnetic susceptibility measurements of these complexes support effective magnetic coupling of all three Ln^III centers through the HAN^3−. radical ligand. Thorough investigation of the Dy^III congener through both ac susceptibility and dc magnetic relaxation measurements reveals slow relaxation of the magnetization, with an effective thermal relaxation barrier of U_eff=51 cm⁻¹. Magnetic coupling in the Dy^III complex enables a large remnant magnetization at temperatures up to 3.0 K in the magnetic hysteresis measurements and hysteresis loops that are open at zero‐field up to 3.5 K.     

Redox‐Controlled Exchange Bias in a Supramolecular Chain of Fe4 Single‐Molecule Magnets

Tetrairon(III) single‐molecule magnets [Fe₄(pPy)₂(dpm)₆] ( 1 ) (H₃pPy=2‐(hydroxymethyl)‐2‐(pyridin‐4‐yl)propane‐1,3‐diol, Hdpm=dipivaloylmethane) have been deliberately organized into supramolecular chains by reaction with Ru^IIRu^II or Ru^IIRu^III paddlewheel complexes. The products [Fe₄(pPy)₂(dpm)₆][Ru₂(OAc)₄](BF₄)_x with x=0 ( 2 a ) or x=1 ( 2 b ) differ in the electron count on the paramagnetic diruthenium bridges and display hysteresis loops of substantially different shape. Owing to their large easy‐plane anisotropy, the s=1 diruthenium(II,II) units in 2 a act as effective s_eff=0 spins and lead to negligible intrachain communication. By contrast, the mixed‐valent bridges (s=3/2, s_eff=1/2) in 2 b introduce a significant exchange bias, with concomitant enhancement of the remnant magnetization. Our results suggest the possibility to use electron transfer to tune intermolecular communication in redox‐responsive arrays of SMMs.     

White Light Emissive DyIII Single‐Molecule Magnets Sensitized by Diamagnetic [CoIII(CN)6]3− Linkers

The self‐assembly of Dy^III–3‐hydroxypyridine (3‐OHpy) complexes with hexacyanidocobaltate(III) anions in water produces cyanido‐bridged {[Dy^III(3‐OHpy)₂(H₂O)₄] [Co^III(CN)₆]}?H₂O ( 1 ) chains. They reveal a single‐molecule magnet (SMM) behavior with a large zero direct current (dc) field energy barrier, ΔE=266(12) cm^?1 (≈385 K), originating from the single‐ion property of eight‐coordinated Dy^III of an elongated dodecahedral geometry, which are embedded with diamagnetic [Co^III(CN)₆]^3? ions into zig‐zag coordination chains. The SMM character is enhanced by the external dc magnetic field, which results in the ΔE of 320(23) cm^?1 (≈460 K) at H_dc=1 kOe, and the opening of a butterfly hysteresis loop below 6 K. Complex 1 exhibits white Dy^III‐based emission realized by energy transfer from Co^III and 3‐OHpy to Dy^III. Low temperature emission spectra were correlated with SMM property giving the estimation of the zero field ΔE. 1 is a unique example of bifunctional magneto‐luminescent material combining white emission and slow magnetic relaxation with a large energy barrier, both controlled by rich structural and electronic interplay between Dy^III, 3‐OHpy, and [Co^III(CN)₆]^3?.     

Influence of Peripheral Substitution on the Magnetic Behavior of Single‐Ion Magnets Based on Homo‐ and Heteroleptic TbIII Bis(phthalocyaninate)

A series of homoleptic ([Tb^III(Pc)₂]) and heteroleptic ([Tb^III(Pc)(Pc′)]) Tb^III bis(phthalocyaninate) complexes that contain different peripheral substitution patterns (i.e., tert‐butyl or tert‐butylphenoxy groups) have been synthesized in their neutral radical forms and then reduced into their corresponding anionic forms as stable tetramethylammonium/tetrabutylammonium salts. All of these compounds were spectroscopically characterized and their magnetic susceptibility properties were investigated. As a general trend, the radical forms exhibited larger energy barriers for spin reversal than their corresponding reduced compounds. Remarkably, heteroleptic complexes that contain electron‐donor moieties on one of the two Pc ligands show higher effective barriers and blocking temperatures than their homoleptic derivatives. This result is assigned to the elongation of the N? Tb distances in the substituted macrocycle, which brings the terbium(III) ion closer to the unsubstituted Pc, thus enhancing the ligand‐field effect. In particular, heteroleptic [Tb^III(Pc)(Pc′)] complex 4 , which contains one octa(tert‐butylphenoxy)‐substituted Pc ring and one bare Pc ring, exhibits the highest effective barrier and blocking temperature for a single‐molecule magnet reported to date.     

(μ‐1,2‐Dimethoxyethane‐κ2O:O′)bis[(1,2‐dimethoxyethane‐κ2O,O′)tris(1,1,1,5,5,5‐hexafluoro‐4‐oxopent‐2‐en‐2‐olato‐κ2O,O′)cerium(III)]

A previous analysis [Fatila et al. (2012). Dalton Trans. 41 , 1352–1362] of the title complex, [Ce₂(C₅HF₆O₂)₆(C₄H₁₀O₂)₃], had identified it as Ce(hfac)₃(dme)_1.5 according to the ¹H NMR integration [hfac = 1,1,1,5,5,5‐hexafluoroacetylacetonate (1,1,1,5,5,5‐hexafluoro‐4‐oxopent‐2‐en‐2‐olate) and dme = 1,2‐dimethoxyethane]; however, it was not possible to determine the coordination environment unambiguously. The structural data presented here reveal that the complex is a binuclear species located on a crystallographic inversion center. Each Ce^III ion is coordinated to three hfac ligands, one bidentate dme ligand and one monodentate (bridging) dme ligand, thus giving a coordination number of nine (CN = 9) to each Ce^III ion. The atoms of the bridging dme ligand are unequally disordered over two sets of sites. In addition, in two of the –CF₃ groups, the F atoms are rotationally disordered over two sets of sites. This is the first crystal structure of a binuclear lanthanide β‐diketonate with a bridging dme ligand.     

Experimental Determination of Magnetic Anisotropy in Exchange‐Bias Dysprosium Metallocene Single‐Molecule Magnets

We investigate a family of dinuclear dysprosium metallocene single‐molecule magnets (SMMs) bridged by methyl and halogen groups [Cp′₂Dy(μ‐X)]₂ (Cp′=cyclopentadienyltrimethylsilane anion; 1 : X=CH₃^?; 2 : X=Cl^?; 3 : X=Br^?; 4 : X=I^?). For the first time, the magnetic easy axes of dysprosium metallocene SMMs are experimentally determined, confirming that the orientation of them are perpendicular to the equatorial plane which is made up of dysprosium and bridging atoms. The orientation of the magnetic easy axis for 1 deviates from the normal direction (by 10.3°) due to the stronger equatorial interactions between Dy^III and methyl groups. Moreover, its magnetic axes show a temperature‐dependent shifting, which is caused by the competition between exchange interactions and Zeeman interactions. Studies of fluorescence and specific heat as well as ab initio calculations reveal the significant influences of the bridging ligands on their low‐lying exchange‐based energy levels and, consequently, low‐temperature magnetic properties.     

Control of the Single‐Molecule Magnet Behavior of Lanthanide‐Diarylethene Photochromic Assemblies by Irradiation with Light

Lanthanide‐based extended coordination frameworks showing photocontrolled single‐molecule magnet (SMM) behavior were prepared by combining highly anisotropic Dy^III and Ho^III ions with the carboxylato‐functionalized photochromic molecule 1,2‐bis(5‐carboxyl‐2‐methyl‐3‐thienyl)perfluorocyclopentene (H₂dae), which acts as a bridging ligand. As a result, two new compounds of the general formula [{Ln^III₂(dae)₃(DMSO)₃(MeOH)} ? 10 M eOH]_n (M=Dy for 1 a and Ho for 2 ) and two additional pseudo‐polymorphs [{Dy^III₂(dae)₃(DMSO)₃(H₂O)} ? x MeOH]_n ( 1 b ) and [{Dy^III₂(dae)₃(DMSO)₃(DMSO)} ? x MeOH]_n ( 1 c ) were obtained. All four compounds have 2D coordination‐layer topologies, in which carboxylate‐bridged Ln₂ units are linked together by dae^2? anions into grid‐like frameworks. All four compounds exhibited a strong reversible photochromic response to UV/Vis light. Moreover, both 1 a and 2 show field‐induced SMM behavior. The slow magnetic relaxation of 1 a is influenced by the photoisomerization reaction leading to the observation of the cross‐effect: photocontrolled SMM behavior.     

Two Lanthanide(III) Complexes based on the Schiff Base N,N′‐Bis(salicylidene)‐1,5‐diamino‐3‐oxapentane: Synthesis,Characterization, DNA‐binding Properties,and Antioxidation

The Schiff base N,N′‐bis(salicylidene)‐1,5‐diamino‐3‐oxapentane (H₂L) and its lanthanide(III) complexes, PrL(NO₃)(DMF)(H₂O) ( 1 ) and Ho₂L₂(NO₃)₂ · 2H₂O ( 2 ), were synthesized and characterized by physicochemical and spectroscopic methods. Single crystal X‐ray structure analysis revealed that complex 1 is a discrete mononuclear species. The Pr^III ion is nine‐coordinate, forming a distorted capped square antiprismatic arrangement. Complex 2 is a centrosymmetric dinuclear neutral entity in which the Ho^III ion is eight‐coordinate with distorted square antiprismatic arrangement. The DNA‐binding properties of H₂L and its Ln^III complexes were investigated by spectrophotometric methods and viscosity measurements. The results suggest that the ligand H₂L and its Ln^III complexes both connect to DNA in a groove binding mode; the complexes bind more strongly to DNA than the ligand. Moreover, the antioxidant activities of the Ln^III complexes were in vitro determined by superoxide and hydroxyl radical scavenging methods, which indicate that complexes 1 and 2 have OH ^· and O₂^{– ·} radical scavenging activity.     

Dinuclear Dy2 Single‐Molecule Magnets: Functional Modulation on the Bridging Ligand and Different Relaxation Performances within the Single‐Crystal to Single‐Crystal System

Crystal structures, single‐molecule magnetic behavior, and ab initio calculations of four new phenoxo‐bridged dinuclear dysprosium complexes and their gadolinium(III) analogues are explored. Complexes [Dy₂(DMOMP)₂(DBM)₄]₂ ? CHCl₃ ( 1 ; DMOMP=1‐methyl‐3,5‐dimethoxy‐4‐hydroxybenzene, DBM=1,3‐diphenylpropane‐1,3‐dione); [Dy₂(DMOAP)₂(DBM)₄]₂ ? CHCl₃ ( 2 ; DMOAP=syringaldehyde); Dy₂(DMOEP)₂(DBM)₄ ( 3 ; DMOEP=methyl syringate); and solvent‐free Dy₂(DMOMP)₂(DBM)₄ ( 4 ), which is obtained by the transformation of single crystal into single crystal from 1 , have nearly identical core structures and only differ in the substituents at the para position of the phenol moieties of the bridging ligand. In this system, the electronic effects are efficiently implemented to significantly modify the ligand field strength and exchange coupling by modulating the substituents on the phenol backbone. The effective energy barrier (U_eff) of magnetization reversal is improved significantly to fivefold magnitude, at most, and the hysteresis temperature up to 3.5 K by deliberately using the electron‐withdrawing substituent to replace the electron‐donating one. The origin of the two relaxation processes in 1 is mostly attributed to the existence of two molecules in one unit, which is illuminated by means of the transformation of single crystal into single crystal.     

Visible‐Light‐Induced Photoredox Catalysis with a Tetracerium‐Containing Silicotungstate

The development of visible‐light‐induced photocatalysts for chemoselective functional group transformations has received considerable attention. Polyoxometalates (POMs) are potential materials for efficient photocatalysts because their properties can be precisely tuned by changing their constituent elements and structures and by the introduction of additional metal cations. Furthermore, they are thermally and oxidatively more stable than the frequently utilized organometallic complexes. The visible‐light‐responsive tetranuclear cerium(III)‐containing silicotungstate TBA₆[{Ce(H₂O)}₂{Ce(CH₃CN)}₂(μ₄‐O)(γ‐SiW₁₀O₃₆)₂] (CePOM; TBA=tetra‐n‐butylammonium) has now been synthesized; when CePOM was irradiated with visible light (λ>400 nm), a unique intramolecular Ce^III‐to‐POM(W^VI) charge transfer was observed. With CePOM, the photocatalytic oxidative dehydrogenation of primary and secondary amines as well as the α‐cyanation of tertiary amines smoothly proceeded in the presence of O₂ (1 atm) as the sole oxidant.     

Rational Electrostatic Design of Easy‐Axis Magnetic Anisotropy in a ZnII–DyIII–ZnII Single‐Molecule Magnet with a High Energy Barrier

Two novel trinuclear complexes [ZnCl(μ‐L)Ln(μ‐L)ClZn][ZnCl₃(CH₃OH)]?3 CH₃OH (Ln^III=Dy ( 1 ) and Er ( 2 )) have been prepared from the compartmental ligand N,N′‐dimethyl‐N,N′‐bis(2‐hydroxy‐3‐formyl‐5‐bromo‐benzyl)ethylenediamine (H₂L). X‐ray studies reveal that Ln^III ions are coordinated by two [ZnCl(L)]^? units through the phenoxo and aldehyde groups, giving rise to a LnO₈ coordination sphere with square‐antiprism geometry and strong easy‐axis anisotropy of the ground state. Ab initio CASSCF+RASSI calculations carried out on 1 confirm that the ground state is an almost pure M_J=±15/2 Kramers doublet with a marked axial anisotropy, the magnetic moment is roughly collinear with the shortest Dy?O distances. This orientation of the local magnetic moment of the Dy^III ion in 1 is adopted to reduce the electronic repulsion between the oblate electron shape of the M_J=±15/2 Kramers doublet and the phenoxo‐oxygen donor atoms involved in the shortest Dy?O bonds. CASSCF+RASSI calculations also show that the ground and first excited states of the Dy^III ion are separated by 129 cm^?1. As expected for this large energy gap, compound 1 exhibits, in a zero direct‐current field, thermally activated slow relaxation of the magnetization with a large U_eff=140 K. The isostructural Zn–Er–Zn species does not present significant SMM behavior as expected for the prolate electron‐density distribution of the Er^III ion leading to an easy‐plane anisotropy of the ground doublet state.     

A Novel Self‐assembled Nickel(II)‐Cerium(III) Heterotetranuclear Dimer Constructed from N2O2‐type Bisoxime and Terephthalic Acid: Synthesis,Structure, and Photophysical Properties

By self‐assembly of a Salamo‐type ligand H₂L [H₂L = 1,2‐bis(3‐methoxysalicylideneaminooxy)ethane] with Ni(OAc)₂ · 4H₂O, Ce(NO₃)₃ · 6H₂O, and H₂bdc (H₂bdc = terephthalic acid), a novel Ni^II‐Ce^III heterometallic complex, [{Ni(L)Ce(NO₃)₂(CH₃OH)(DMF)}₂(bdc)], was obtained. Two crystallographically equivalent [Ni(L)Ce(NO₃)₂(CH₃OH)(DMF)] moieties lie in the inversion center, and are linked by one bdc^2– ligand leading to a heterotetranuclear dimer, in which the carboxylato group bridges the Ni^II and Ce^III atoms. Moreover, the photophysical properties of the Ni^II‐Ce^III complex were studied.     

Hydrothermal Syntheses,Crystal Structures,and Luminescent Properties of Three Organic‐Lanthanide Complexes with 3‐Hydroxycinnamic Acid

Three new homodinuclear lanthanide(III) complexes [Ln₂(L)₆(2,2′‐bipy)₂] [Ln = Tb^III ( 1 ), Sm^III ( 2 ), Eu^III ( 3 ); HL = 3‐hydroxycinnamic acid (3‐HCA); 2,2′‐bipy = 2,2′‐bipyridine] were synthesized and characterized by IR spectroscopy, elemental analyses, and X‐ray diffraction techniques. Complexes 1 – 3 crystallize in triclinic system, space group P$\bar{1}$ . In all complexes the lanthanide ions are nine‐coordinate by two nitrogen atoms from the 2,2′‐bipy ligand and seven oxygen atoms from one chelating L ligands and four bridging L ligands, forming distorted tricapped trigonal prismatic arrangements. The lanthanide(III) ions are intramolecularly bridged by eight carboxylate oxygen atoms forming dimeric complexes with Ln ··· Ln distances of 3.92747(15), 3.9664(6), and 3.9415(4) Å for complexes 1 – 3 , respectively. The luminescent properties in the solid state of HL ligand and Eu^III complex are also discussed.     

Ruthenium(II/III)‐Based Compounds with Encouraging Antiproliferative Activity against Non‐small‐Cell Lung Cancer

Hereby we present the synthesis of several ruthenium(II) and ruthenium(III) dithiocarbamato complexes. Proceeding from the Na[trans‐Ru^III(dmso)₂Cl₄] ( 2 ) and cis‐[Ru^II(dmso)₄Cl₂] ( 3 ) precursors, the diamagnetic, mixed‐ligand [Ru^IIL₂(dmso)₂] complexes 4 and 5 , the paramagnetic, neutral [Ru^IIIL₃] monomers 6 and 7 , the antiferromagnetically coupled ionic α‐[Ru^III₂L₅]Cl complexes 8 and 9 as well as the β‐[Ru^III₂L₅]Cl dinuclear species 10 and 11 (L=dimethyl‐ (DMDT) and pyrrolidinedithiocarbamate (PDT)) were obtained. All the compounds were fully characterised by elemental analysis as well as ¹H NMR and FTIR spectroscopy. Moreover, for the first time the crystal structures of the dinuclear β‐[Ru^III₂(dmdt)₅]BF₄ ? CHCl₃ ? CH₃CN and of the novel [Ru^IIL₂(dmso)₂] complexes were also determined and discussed. For both the mono‐ and dinuclear Ru^II and Ru^III complexes the central metal atoms assume a distorted octahedral geometry. Furthermore, in vitro cytotoxicity of the complexes has been evaluated on non‐small‐cell lung cancer (NSCLC) NCI‐H1975 cells. All the mono‐ and dinuclear Ru^III dithiocarbamato compounds (i.e., complexes 6 – 10 ) show interesting cytotoxic activity, up to one order of magnitude higher with respect to cisplatin. Otherwise, no significant antiproliferative effect for either the precursors 2 and 3 or the Ru^II complexes 4 and 5 has been observed.