Synthesis, characterisation and substitution kinetics of unusually labile trans-[Co(tmen)(diamine)Cl2] complexes

The mixed diamine complexes trans-[Co(tmen)(diamine)Cl₂]⁺ have been synthesised (tmen = NH₂C(Me)₂C(Me)₂NH₂; diamine = en = NH₂(CH₂)₂NH₂, and ibn = NH₂C(Me)₂CH₂NH₂). Replacement of one en ligand in trans-[Co(en)₂Cl₂]⁺ by one tmen ligand engenders an enormous rate enhancement (2000-fold) for acid hydrolysis. Solvolysis rates have been measured in Me₂SO and DMF for these complexes and also trans-[Co(tmen)₂Cl₂]⁺ which is more reactive again (10⁴-fold). The measured reactivities in DMF at 2 °C establish that the kinetic effect of replacing each en by tmen is incremental, and the extreme base catalysed racemisation rate for (+)-[Co(tmen)₃]³⁺ can now be explained on this basis.     

Study of Pt(II)-cyclic amines complexes of the types cis- and trans-Pt(amine)2I2 and cis- and trans-Pt(amine)2(NO3)2 and their aqueous products by

Complexes of the types cis- and trans-Pt(amine)₂I₂ containing cyclic amines were synthesized and studied mainly by IR and multinuclear NMR spectroscopies. The compounds were converted to cis- and trans-Pt(amine)₂(NO₃)₂, which were also investigated. The hydrolysis and the aquation reactions of the latter compounds were then studied in D₂O in different conditions of pH. In acidic medium, the aqueous product is [Pt(amine)₂(D₂O)₂]²⁺ and for a few amines, [Pt(amine)₂(D₂O)(NO₃)]⁺ was detected. In basic pH, the main product is Pt(amine)₂(OD)₂ and Pt(amine)₂(OD)(NO₃) was detected for several compounds. In neutral pH, the cis isomers form between two and four species in fresh solutions. The most shielded species in ¹⁹⁵Pt NMR is the monoaqua-monohydroxo complex cis-[Pt(amine)₂(D₂O)(OD)]⁺ and the less shielded compound is the dihydroxo-bridged dimer [Pt(amine)₂(μ-OD)₂Pt(amine)₂]²⁺, which were observed for all the compounds. For a few amines, the monohydroxo-bridged dimer [Pt(D₂O)(amine)₂(μ-OD)Pt(OD)(amine)₂]²⁺ was detected and for cyclohexylamine, a fourth signal was assigned to a cyclic hydroxo-bridged trimer [(Pt(amine)₂(μ-OD))₃]³⁺. ¹⁹⁵Pt NMR spectroscopy has shown that the concentration of the monomer decreases with time, while the concentration of the dimers increases. Only one product was observed for the trans isomers in neutral pH. The signal was assigned to the monoaqua-monohydroxo species trans-[Pt(amine)₂(D₂O)(OD)]⁺. The ¹³C and ¹H NMR spectra of most of the complexes were measured. All the coupling constants ^2,3J(¹⁹⁵Pt-¹H) and ^2,3J(¹⁹⁵Pt-¹³C) are larger in the cis compounds than in the trans isomers.     

Reduction of acetonitrile by neodymium diiodide: Molecular structure of [{(HNCMe)2MeCNH2}NdI(MeCN)5]I2 and [{(HNCMe)2MeCNH2}Nd(MeCN)6]I3

The reaction of neodymium diiodide NdI₂ (1) with acetonitrile is accompanied by C-C coupling and formation of bis(ethylimine)ethylamine/acetonitrile complexes {[(MeCNH)₂CMeNH₂]NdI(MeCN)₅}I₂ (2) and {[(MeCNH)₂CMeNH₂]Nd(MeCN)₆}I₃ (3). Yields of the products are 9% and 50%, respectively. Probable scheme of the complexes formation is discussed. Treatment of 3 with 2 equiv. of 1 in THF affords NdI₃(THF)₃, hydrogen and monoiodide complex containing presumably bis(imide)amine ligand, NdI[(MeCN)₂CMeNH₂]. The X-ray analysis revealed that in the molecule of 2 one I⁻ anion is directly bonded to Nd³⁺ cation while two other I⁻anions are not in contact to the metal centre. The molecule of 3 is isostructural to previously obtained Dy and Tm analogues. All three I⁻ anions in it are located away from Nd³⁺ cation.     

Reactivity of trans-[PtCl2(NCMe)2] with cycloaliphatic amines: An ESI and NMR study. X-ray structure of

The reactivity of the cyclic primary aliphatic amines cyclopropyl-, cyclopentyl- and cyclohexylamine with cis- and trans-[PtCl₂(NCMe)₂], under the same experimental conditions, is compared. Whereas cis-[PtCl₂(NCMe)₂] yields the neutral diamidine compounds, the reactions with trans-[PtCl₂(NCMe)₂] take place either with addition or substitution processes yielding the neutral diamidine complexes trans-[PtCl₂(Amidine)₂], the monocationic trans-[PtCl(Amine)(Amidine)₂]Cl and the dicationic trans-[Pt(Amine)₂(Amidine)₂]Cl₂ salts. An NMR and ESI study indicate that the main species formed is the monocationic trans-[PtCl(Amine)(Amidine)₂]Cl complex.The X-ray structure of is reported and its supramolecular arrangement is described.     

Synthesis and study of Pt(II)-aromatic amines complexes of the types cis- and trans-Pt(amine)2(NO3)2 and cis-Pt(amine)2(R(COO)2)

Complexes of the types cis- and trans-Pt(amine)₂(NO₃)₂ with amines containing a phenyl group were synthesized and studied mainly by IR and multinuclear magnetic resonance spectroscopies. The cis complexes could be synthesized pure only with the amines of the type Ph-R-NH₂ (R = alkyl), while pure trans compounds were synthesized with all the studied amines. In ¹⁹⁵Pt NMR spectroscopy, the dinitrato complexes of the amines Ph-R-NH₂ were observed around −1700 ppm for the cis isomers and at about −1580 for the trans complexes. For the other amines, where a phenyl ring is directly attached to the amino group, the signals were observed at lower fields, −1528 ppm for cis-Pt(PhNH₂)(NO₃)₂ and around −1450 ppm for all the trans isomers. There is a linear relationship between the δ(Pt) of the Pt(amine)₂(NO₃)₂ complexes and the pK_a of the protonated amines. The coupling constants ²J(¹⁹⁵Pt-¹HN) are larger in the cis compounds (ave. 76 Hz) than in the trans isomers (ave. 63 Hz). The complexes cis-Pt(amine)₂(R(COO)₂) with bidentate dicarboxylato ligands were also synthesized and characterized mainly by IR spectroscopy. The compounds apparently decompose in DMF and are too insoluble in other solvents for solution studies.     

Synthesis and characterization of [Co(NO2)2(acac)(IMH2py)] with one-electron-reduced imino nitroxide radical associated with unusual displacement of acetylacetonate in the starting complex trans-Na[Co(NO2)2(acac)2]

A reaction of trans-Na[Co(NO₂)₂(acac)₂] with IM2py(2(2^′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl) in methanol afforded trans-[Co(NO₂)₂(acac)(IMH2py)](IMH2py=1-hydroxyl-2(2^′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole); one-electron reduction of the N-O radical moiety in IM2py and displacement of one of the two acac ligands with retention of two nitrito ligands in the starting complex during the reaction. This new complex was characterized by UV-Vis, ¹H NMR spectra and X-ray analysis.     

Ligand substitution reactions and cytotoxic properties of [Au(L)Cl2] and [AuCl2(DMSO)2] complexes (L = ethylenediamine and S-methyl-l-cysteine)

We have studied the kinetics of the complex formation of gold(III) complexes, [AuCl₂(en)]⁺ (dichlorido(ethylenediamine)aurate(III)-ion) and [AuCl₂(SMC)] (dichlorido (S-methyl-l-cysteine)aurate(III)) with four biologically N-donor nucleophiles. It was shown that studied ligands have a high affinity for gold(III) complex, which may have important biological implications, since the interactions of Au(III) with DNA is thought to be responsible for the anti-tumour activity. The [AuCl₂(SMC)] complex is more reactive than [AuCl₂(en)]⁺. L-His reacts faster than the other N-donor nucleophiles in the reaction with [AuCl₂(en)]⁺, but in the reaction with [AuCl₂(SMC)] 5′-GMP is the best nucleophile. Gold(III) complexes are much more reactive than Pt(II) complexes with the same nucleophiles. The activation parameters for all studied reactions suggest an associative substitution mechanism. The cytotoxicity of gold(III) complexes, [AuCl₂(en)]⁺, [AuCl₂(SMC)] and [AuCl₂(DMSO)₂]⁺ was evaluated in vitro against chronic lymphocytic leukemia cells, obtained from blood of patients with chronic lymphocytic leukemia (CLL). The [AuCl₂(en)]⁺ complex show comparable cytotoxicity profiles compared to cisplatin.     

Cobalt(II) and cadmium(II) chelates with nitrogen donors and O2 bonding to Co(II) derivatives

The formation of Cd(II) and Co(II) complexes with N-methylethylenediamine (men) has been studied at 298 K in dimethylsulfoxide (dmso) in an ionic medium set to 0.1 mol dm⁻³ with Et₄NClO₄ in anaerobic conditions by means of potentiometric, UV-Vis, calorimetric and FT-IR technique. Mononuclear ML_j (M=Cd, Co; j=1-3) complexes are formed in exothermic reactions, whereas the entropy changes oppose the complexes formation. The results are discussed in terms of different basicities and steric requirements and the whole of the thermodynamic data reported till now for the two ions with a number of diamines are summarized to visualize the selectivity of the ligands. The dioxygen uptake of Co(men)₂ species has also been studied by means of UV-Vis and EPR techniques. The kinetic parameters and stability constants obtained for the formation of the superoxo and μ-peroxo species are discussed in terms of solvent effect and steric hindrance due to methyl group.Cyclic voltammetry was used to confirm the stability constant for the Co(dmen)₂ (dmen=N,N^′-dimethylethylenediamine) superoxo adduct formation but was not successful to investigate this Co(men)₂-O₂ system.     

Kinetics and mechanism of the complex formation of [Pd(NNN)Cl] with pyridines in methanol: synthesis and crystal structure of [Pd(terpy)(py)](ClO4)2

The kinetics of the complex-formation reactions between monofunctional palladium(II) complexes [Pd(NNN)Cl]⁺, where NNN is 2,2^′:6^′,2″-terpyridine (terpy), diethylenetriamine (dien) or bis(2-pyridylmethyl)amine (bpma), with pyridine, 4-methylpyridine, 4-acetylpyridine, 4-cyanopyridine and 4-aminopyridine, have been studied in methanol at 25 °C using stopped-flow spectrophotometry. The highest reactivity was observed for the [Pd(terpy)Cl]⁺ complex, whereas 4-aminopyridine is the strongest nucleophile. The results, compared with those previously published on the [Pt(NNN)Cl]⁺ complexes, are discussed in terms of reactivity and discrimination ability of the reaction centre. The crystal structure of [Pd(terpy)(py)](ClO₄)₂ has been determined by X-ray diffraction. Crystals are triclinic, space group , and consist of distorted square planar [Pd(terpy)(py)]²⁺ cations and perchlorate anions. The Pd-N bond length to the central atom of terpy ligand is well below 2.0 Å and significantly shorter than any of the other M-N distances. The pyridine plane forms a dihedral angle of 61.9(2)° with the coordination N4 donors.     

Synthesis and structures of bimetallic silicon-containing imido alkylidene complexes of molybdenum Me2Si[CHMo(NAr)(ORF3)2]2 and PhVinSi[CHMo(NAr)(ORF3)2]2

Bimetallic alkylidene complexes of molybdenum (R_F3O)₂(ArN)MoCH-SiMe₂-CHMo(NAr)(OR_F3)₂ (1) and (R_F3O)₂(ArN)MoCH-SiPhVin-CHMo(NAr)(OR_F3)₂ (2) (Ar = 2,6-C₆H₃; R_F3 = CMe₂CF₃) have been prepared by the reactions of vinyl silicon reagents Me₂Si(CHCH₂)₂ and PhSi(CHCH₂)₃ with known alkylidene compound PhMe₂C-CHMo(NAr)(OR_F3)₂. Complexes 1 and 2 were structurally characterized. Ring opening metathesis polymerization (ROMP) of cyclooctene using compounds 1 and 2 as initiators led to the formation of high molecular weight polyoctenamers with predominant trans-units content in the case of 1 and predominant cis-units content in the case of 2.     

Multinuclear NMR study and crystal structures of complexes of the types cis- and trans-Pt(amine)2I2

Complexes of the types cis- and trans-Pt(amine)₂I₂ were studied by spectroscopic methods, especially by multinuclear NMR spectroscopy. In ¹⁹⁵Pt NMR, the cis diiodo compounds with primary amines were observed between −3342 and −3357 ppm in acetone, while the trans compounds were found between −3336 and −3372 ppm. For the secondary amines, the chemical shifts were observed at lower fields. In ¹H NMR, the trans complexes were observed at higher fields than the cis compounds, while in ¹³C NMR, the reverse was observed. The ²J(¹⁹⁵Pt-¹H) and ³J(¹⁹⁵Pt-¹H) coupling constants are larger for the cis compounds (ave. 67 and 45 Hz, respectively) than for the trans isomers (ave. 59 and 38 Hz). In ¹³C NMR, the values of ²J(¹⁹⁵Pt-¹³C) and ³J(¹⁹⁵Pt-¹³C) were also found to be larger for the cis complexes (ave. 17 and 39 Hz versus 11 and 28 Hz). There seems to be a slight dependence of the pK_a values of the protonated amines or the proton affinity in the gas phase with the δ(Pt) chemical shifts. The crystal structures of eight diiodo complexes were determined. These compounds are cis-Pt(CH₃NH₂)₂I₂, cis-Pt(n-C₄H₉NH₂)₂I₂, cis-Pt(Et₂NH)₂I₂, trans-Pt(n-C₃H₇NH₂)₂I₂, trans-Pt(iso-C₃H₇NH₂)₂I₂, trans-Pt(n-C₄H₉NH₂)₂I₂, trans-Pt(t-C₄H₉NH₂)₂I₂ and trans-Pt(Me₂NH)₂I₂. The Pt-N bond distances located in trans position to the iodo ligands were compared to those located in trans position to the amines. The Pt-N bond in cis-Pt(Et₂NH)₂I₂ are much longer than the others, probably caused by the steric hindrance of the two very bulky ligands located in cis positions.     

Kinetic studies on the reactions of HCl with trans-[MoL(CNPh)(Ph2PCH2CH2PPh2)2] (L=N2, H2 or CO)

The kinetics of the reactions between anhydrous HCl and trans-[MoL(CNPh)(Ph₂PCH₂CH₂PPh₂)₂] (L=CO, N₂ or H₂) have been studied in thf at 25.0 °C. When L=CO, the product is [MoH(CO)(CNPh)(Ph₂PCH₂CH₂PPh₂)₂]⁺, and when L=H₂ or N₂ the product is trans-[MoCl(CNHPh)(Ph₂PCH₂CH₂PPh₂)₂]. Using stopped-flow spectrophotometry reveals that the protonation chemistry of trans-[MoL(CNPh)(Ph₂PCH₂CH₂PPh₂)₂] is complicated. It is proposed that in all cases protonation occurs initially at the nitrogen atom of the isonitrile ligand to form trans-[MoL(CNHPh)(Ph₂PCH₂CH₂PPh₂)₂]⁺. Only when L=N₂ is this single protonation sufficient to labilise L to dissociation, and subsequent binding of Cl⁻ gives trans-[MoCl(CNHPh)(Ph₂PCH₂CH₂PPh₂)₂]. At high concentrations of HCl a second protonation occurs which inhibits the substitution. It is proposed that this second proton binds to the dinitrogen ligand. When L=CO or H₂, a second protonation is also observed but in these cases the second protonation is proposed to occur at the carbon atom of the aminocarbyne ligand, generating trans-[MoL(CHNHPh)(Ph₂PCH₂CH₂PPh₂)₂]²⁺. Addition of the second proton labilises the trans-H₂ to dissociation, and subsequent rapid binding of Cl⁻ and dissociation of a proton yields the product trans-[MoCl(CNHPh)(Ph₂PCH₂CH₂PPh₂)₂]. Dissociation of L=CO does not occur from trans-[Mo(CO)(CHNHPh)(Ph₂PCH₂CH₂PPh₂)₂]²⁺, but rather migration of the proton from carbon to molybdenum, and dissociation of the other proton produces [MoH(CO)(CNPh)(Ph₂PCH₂CH₂PPh₂)₂]⁺.     

Synthesis and structural characterization of a novel diosmium(III) compound: Os2(ap)4Cl2

The reaction between Os₂(OAc)₄Cl₂ and Hap (Hap is 2-anilinopyridine) under prolonged refluxing conditions resulted in a new Os₂(III) compound, Os₂(ap)₄Cl₂ (1). The molecular structure of 1 was determined from a single crystal X-ray diffraction study, which revealed an Os-Os bond length of 2.396[1] Å, and a cis-(2,2) arrangement of the ap ligands. Also reported are magnetic, electrochemical and spectroscopic properties of 1.     

Synthesis and multinuclear magnetic resonance spectroscopy of the novel ionic Pt(II) mixed-ligands complexes cis- and trans-[Pt(pyrazine)2(Ypy)2](NO3)2 where Ypy = pyridine derivative

Novel ionic mixed-ligands complexes of the types cis- and trans-[Pt(pz)₂(Ypy)₂](NO₃)₂ (where Ypy is a pyridine derivative and pz = pyrazine) were synthesized and studied mainly in the solid state by IR spectroscopy and in aqueous solution by multinuclear (¹⁹⁵Pt, ¹H and ¹³C) magnetic resonance spectroscopy. The trans isomers with ligands containing a methyl group in ortho position on the pyridine ring could not be synthesized. The results of the solution NMR characterization have shown that the isolated compounds are pure. In ¹⁹⁵Pt NMR, the cis complexes containing a methyl group in ortho positions were observed at lower field (average −2337 ppm) than the other cis compounds (average −2427 ppm), which is explained by the solvent effect. The trans isomers were observed at very slightly lower fields (average −2422 ppm) than the equivalent cis complexes (average −2427 ppm). In ¹H NMR, the coupling constants ³J(¹⁹⁵Pt-¹H_Ypy) and ³J(¹⁹⁵Pt-¹H_pz) are larger in the cis compounds (∼40 Hz) than in the trans complexes (∼31 Hz). A few ⁴J(¹⁹⁵Pt-¹H_pz) were observed (∼16 Hz). In ¹³C NMR spectroscopy, the coupling constants ³J(¹⁹⁵Pt-¹³C_pz) and ³J(¹⁹⁵Pt-¹³C_Ypy) are also larger in the cis configuration (∼30 and ∼38 Hz, respectively) than in the trans isomers (∼20 Hz). One ⁴J(¹⁹⁵Pt-¹³C_pz) could be calculated (17 Hz). The presence of the syn and anti rotamers were observed in all the cis complexes containing a pyridine derivative with a -CH₃ group in ortho position. They were observed in ¹⁹⁵Pt, ¹H and ¹³C NMR spectroscopy. The proportion of the two rotamers is about 55% and 45%.     

Quantifying the trans influence of triphenylarsine. Crystal and molecular structures of cis-[PtCl2(SMe2)(AsPh3)] and cis-[PtCl2(AsPh3)2]·CHCl3

Reaction between a mixture of cis-trans-[PtCl₂(SMe₂)₂] and 1 equiv. AsPh₃ in chloroform gives cis-[PtCl₂(SMe₂)(AsPh₃)] crystallizing in P2₁/n with a=10.397(2), b=14.876(3), c=13.956(3) Å, β=90.86(3)° and Z=4. Selected geometrical parameters are PtAs 2.3531(10), PtS 2.262(2), PtCl (trans to S) 2.301(2), PtCl (trans to As) 2.328(2) Å and SPtAs 88.85(6), SPtCl(2) 90.77(8), AsPtCl(1) 91.07(6) and ClPtCl 89.42(7)°. cis-[PtCl₂(AsPh₃)₂]·CHCl₃ crystallizes in P2₁/c with a=20.557(4), b=9.5951(19), c=20.147(4) Å, β=96.77(3)° and Z=4. Selected geometrical parameters are PtAs(1) 2.3599(9), PtAs(2) 2.3770(9), PtCl(1) (trans to As(1)) 2.3515(18), PtCl(2) (trans to As(2)) 2.3251(18) Å and AsPtAs 97.87(3), As(1)PtCl(2) 88.67(5), As(2)PtCl(1) 84.30(5) and ClPtCl 89.32(7)°. By comparison with related structures from the literature the following trans influence series was established PMe₂Ph>PPh₃>AsPh₃≈SbPh₃>Me₂SO≈SMe₂≈SPh₂>NH₃≈olefin>Cl⁻>MeCN.     

Geometrical isomers of bis(benzimidazol-2-ylethyl)sulfide)cobalt(II) diperchlorates: synthesis, structure, spectra and redox behavior of pink-[Co(bbes)2](ClO4)2 and blue-[Co(bbes)2](ClO4)2

1:1 and 1:2 cobalt complexes of bis(benzimidazol-2-ylmethyl)amine (bbma) bis(benzimidazol-2-ylmethyl)sulfide (bbms), bis(benzimidazol-2-ylethyl)sulfide (bbes) and diethylenetriamine (dien) were prepared and their spectral and redox behavior studied. Two geometrical isomers pink-[Co(bbes)₂]²⁺ and blue-[Co(bbes)₂]²⁺ were obtained when the complexes were prepared by using with bbes and they were separated manually and recrystallized. The octahedral structure of pink-[Co(bbes)₂]²⁺ was resolved by X-ray analysis. The electronic spectra show the presence of two geometrical isomers for Co(bbes)₂²⁺ in the solid state; for example, the spectral bands of pink-[Co(bbes)₂]²⁺ differs markedly with those of blue-[Co(bbes)₂]²⁺. This is consistent with the results obtained from magnetic measurements (5.10 BM for pink-Co(bbes)₂²⁺ and 4.72 BM for blue-[Co(bbes)₂]²⁺). Further, the behavior of the ligands (bbma, bbms, bbes) at different pH conditions was determined on the basis of ¹³C NMR studies. The redox potentials [Co(II)/Co(I)] of the complexes follow the trend [Co(bbma)₂]²⁺ < [Co(bbms)₂]²⁺ ≈ [Co(bbes)₂]²⁺ which demonstrates the stabilization of the Co(II) ion is more by both weak σ-donor and weak π-acceptor ligands rather than by σ-donor ligand.     

A new example of a tetranuclear iron(III) cluster containing the [Fe4O2] core: preparation, X-ray crystal structure, magnetochemistry and Mössbauer study of [Fe4O2(O2CMe)6(N3)2(phen)2]

Two synthetic procedures have been employed that allow access to the new tetranuclear cluster [Fe₄O₂(O₂CMe)₆(N₃)₂(phen)₂] (1), where phen is 1,10-phenanthroline. Complex 1 · 3MeCN displays an unusual structural asymmetry (observed for the second time) in its [Fe₄O₂]⁸⁺ core that can be considered as a hybrid of the bent (butterfly) and planar dispositions of four metal ions seen previously in such compounds with transition metals. Complex 1 has been characterized by variable-temperature magnetic susceptibility studies, and by IR and variable-temperature ⁵⁷Fe Mössbauer spectroscopies. Magnetochemical data reveal a diamagnetic ground state (S=0) with antiferromagnetic body-body and body-wingtip interactions between the iron(III) ions of the butterfly core (J_bb=−11 cm⁻¹, J_wb=−70 cm⁻¹). Magnetochemical and Mössbauer studies on 1 show that its structural asymmetry has practically no influence on these properties compared with the more symmetric types.     

Further kinetics studies of intermediates formed by flash photolysis of Mo(CO)6

Kinetics studies of the behavior of Mo(CO)₅(CH) in the presence of radical initiators were conducted in cyclohexane (CH) solution by laser flash photolysis with time-resolved infrared detection. Activation parameters were determined for reactions of Mo(CO)₅(CH) with toluene and with photochemical radical generator dibenzylketone (DBK) in the presence of excess CO.     

Spectroscopic and electrochemical properties of a new nitrosyl-complex of Ru(II): trans-[Ru(NO){(CH3CH2)2PCH2CH2P(CH2CH3)2}2Cl](PF6)2

A new ruthenium nitric oxide complex with the bidentate phosphine, 1,2-bis(diethylphosphino)ethane (depe), has been synthesized and characterized by UV-Vis, infrared, EPR, NMR, electrochemical techniques and X-ray structure determination. The electronic spectrum showed a typical band of dπ→pπ* charge-transfer (CT) transition, assigned to Ru(II)NO transition, and the vibrational spectrum exhibited a peak of nitrosyl ligand at (ν_NO=1851 cm⁻¹). A model structure for this complex has been proposed based on ¹H, ¹H{³¹P}, ³¹P{¹H}, ¹³C{¹H}, COSY ¹H¹H{³¹P}, J-Resolved, HSQC, HMBC, HSQC ¹H¹³C{³¹P} and ¹H¹³C HSQC/¹H¹H TOCSY spectral data, and confirmed by X-ray diffraction. The nitrosonium character for the NO ligand become evident through both electron paramagnetic resonance and X-ray data (angle RuNO=177.4(3)°). The reversible monoeletronic process at E_1/2=0.040 V versus SHE was assigned to the ligand NO⁺/NO redox couple. Under treatment with Cd(Hg) solutions containing the [Ru(NO)(depe)₂Cl](PF₆)₂ yields a signal in the EPR spectrum (g_⊥=1.99 and g_//=1.88) which fitted quite well with the simulated spectra of coordinated NO species.     

Functionalised dithiocarbamate complexes: Synthesis and molecular structures of bis(2-methoxyethyl)dithiocarbamate complexes [M{S2CN(CH2CH2OMe)2}2] (M = Ni, Cu, Zn) and [Cu{S2CN(CH2CH2OMe)2}2][ClO4]

The bis(2-methoxyethyl)dithiocarbamate complexes [M{S₂CN(CH₂CH₂OMe)₂}₂] (M = Ni, Cu, Zn, Pd) are readily prepared and the three lighter complexes have been crystallographically characterised. Disproportionation of [Cu{S₂CN(CH₂CH₂OMe)₂}₂] upon addition of Cu(ClO₄)₂ · 6H₂O affords the copper(III) complex [Cu{S₂CN(CH₂CH₂OMe)₂}₂][ClO₄] which has also been crystallographically characterised. Unlike other copper(III) dithiocarbamate salts, there are no intermolecular cation-cation or cation-anion interactions.