Single-charged Cations Research Articles

Association of 5,5′-Dibromo-o-Cresolsulfonphthalein Anions with Dye Cations in Aqueous Solution

The formation of associates in aqueous solutions between single- or double-charged anions of 5,5′-dibromo-o-cresolsulfonphthaleine and single-charged cations of cyanine dyes (quinaldine blue, quinaldine red) has been considered. Based on the spectrophotometric data, the equilibrium constants of the association were analyzed. The energy of cation-anion interactions (standard enthalpy of formation of ions and associates) was determined by the semi-empirical AM1 method and probable structures of associates were set. The consistency between experimental spectrophotometric and calculated quantum chemical data is discussed.

CRYSTAL GROWTH OF ARGYRODITE Ag8GeS6

The mineral Ag8GeS6 is the first compound of a wide class of tetrahedrally close packed phases united by the common name argyrodites. Ternary argyrodites are complex chalcogenides formed on the basis of multi- and single-charged cations. Structural polyhedrons are tetrahedra formed on the basis of a multicharged cation and chalcogens, and the single-charged cations occupy the formed voids. Argyrodites belong to promising solid-state conductors and thermoelectric materials. This work is aimed to develop close to optimal conditions for single crystals growth of Ag8GeS6 by the method of directional crystallization from the melt. The initial Ag8GeS6 alloy was obtained using high purity elementary components by a two-stage single-temperature method. The congruent nature of the melting of Ag8GeS6 (Tmelt = 958°C) and the passage of the structural phase transition Pna21 → F-43m at a temperature of 227 ° C was confirmed by the DTA method. The Ag8GeS6 single crystal was grown from the melt by directional crystallization method. The growth regime of Ag8GeS6 was selected taking into account the nature of the thermal behavior of the compound based on DTA data. The grown single crystal of Ag8GeS6 is ~ 30 mm long and 12 mm in diameter and has a medium degree of cleavage. According to the results of XRD analysis, it was established that the obtained single crystalline sample of Ag8GeS6 is single-phase and crystallizes by low-temperature modification SG Pna21 with following lattice parameters: a = 15.147 Å, b = 7.469 Å, c = 10.584 Å.

Bromocresol purple in the processes of cation-anionic interactions in aqueous solutions: UV–Vis spectroscopy and computer simulation of dissimilar association

The formation of associates between single- or double-charged anions of bromocresol purple (3,3′-dimethyl-5,5′-dibromophenolsulfonephthalein) and single-charged cations of cyanines (quinaldine blue, quinaldine red) has been investigated. The equilibrium constants of the association have been determined on the basis of UV–Vis spectroscopy data. The energy of the cation-anion interaction (the standard enthalpy of formation of ions and associates), as well as the probable structure of associates, were established using the PM7 semiempirical method. The presented results can be useful in the development of new spectroscopic methods for the detection of organic additives in water (e.g. acetone) due to the spectral properties of dissimilar associates.

Synthesis, Structure, and Radioprotective Activity of the Palladium (II) Complex With Mexidol

New complex compounds of palladium (II) with biologically active ligand 2 - ethyl - 6 methyl - 3 - hydroxy-pyridine - mexidol in acidic medium (pH = 5,3) of the following composition have been synthesized – (C8H12O⊕N)2 [PdCl4]. In this case, the ligand is protonated and as a single-charged cation occupies an external coordination sphere. The structure of the complex is proved by X-ray structure analysis. It is shown that the structure is constructed of an isolated complex anion [PdCl4]2- and cation C8H12O⊕N. The square planar coordination of the palladium atom is formed from three chlorine atoms and the formed tetraacidoanion ligand forms a hydrogen bond. The average length of Pd-Cl bond is 2, 3030 Α°, there are no deviations from 900 valence angles of Cl-Pd-Cl. The palladium atom is not shifted from the plane coordination polyhedron (square) and therefore trance angles of Cl-Pd-Cl are 1800. Two different lengths -2,289 Α° and 2,713 Α° of hydrogen bonds are related to the geometric location of the ligand functional group. The obtained 2 – ethyl – 6 – methyl – 3 -hydroxypyridinetrachloro - palladium - mexidazole was tested for radioprotective properties. Toxicity of the preparation is LD50 - 240 mg/kg of animal weight. Toxicological studies of mexidazole in mice, rats and dogs did not reveal cardiotoxic, immunotoxic, embryonic, nephrotoxic, hematoxic and other types of side effects. Mexidazole is removed from the body with urine 5-8 hours after intravenous injection. The carried out biological test showed that the compound, along with radioprotective properties, has some antitumor activity.

Synthesis, Structure, and Radioprotective Activity of the Palladium (II) Complex with Mexidol

New complex compounds of palladium (II) with biologically active ligand 2 - ethyl - 6 methyl - 3 - hydroxy-pyridine - mexidol in acidic medium (pH = 5,3) of the following composition have been synthesized – . In this case, the ligand is protonated and as a single-charged cation occupies an external coordination sphere. The structure of the complex is proved by X-ray structure analysis. It is shown that the structure is constructed of an isolated complex anion – and cation . The square planar coordination of the palladium atom is formed from three chlorine atoms and the formed tetraacidoanion ligand forms a hydrogen bond. The average length of Pd-Cl bond is 2, 3030 , there are no deviations from 900 valence angles of Cl-Pd-Cl. The palladium atom is not shifted from the plane coordination polyhedron (square) and therefore trance angles of Cl-Pd-Cl are 1800. Two different lengths -2,289 and 2,713 of hydrogen bonds are related to the geometric location of the ligand functional group. The obtained 2 – ethyl – 6 – methyl – 3 -hydroxypyridinetrachloro - palladium - mexidazole was tested for radioprotective properties. Toxicity of the preparation is LD50 - 240 mg/kg of animal weight. Toxicological studies of mexidazole in mice, rats and dogs did not reveal cardiotoxic, immunotoxic, embryonic, nephrotoxic, hematoxic and other types of side effects. Mexidazole is removed from the body with urine 5-8 hours after intravenous injection. The carried out biological test showed that the compound, along with radioprotective properties, has some antitumor activity.

Formation, Stability, and Coagulation of Fullerene Organosols: C70 in Acetonitrile-Toluene Solutions and Related Systems.

This paper is aimed at better understanding the nature of C70 aggregates in organic solvents. As liquid media, acetonitrile-toluene mixed solvents were chosen. At a high content of CH3CN, e.g., 90 vol %, colloidal particles with a size of ca. 225 ± 10 nm are formed with a negative ζ-potential of -(55 ± 5) mV and are stable over time. The interaction with electrolytes containing single-, double-, and triple-charged cations was examined using dynamic light scattering and UV-visible spectra. Additional experiments were carried out with methanol and benzene instead of acetonitrile and toluene, respectively. For comparison, data were obtained with C60 organosols. It was found that coagulation obeys the classical Schulze-Hardy rule. The specificity of the coagulating power of various single-charged cations was explained by their different abilities to adsorb on negatively charged C70 aggregates. The overcharging effect is expressed not only for Ca2+ and La3+ ions but even for Li+ and is caused by poor solvation of such cations in a cationophobic solvent, acetonitrile. After introduction of the cryptand [2.2.2], a substantial increase in the critical concentrations of coagulation for Na+, Li+, and Ca2+ was observed owing to conversion of "bare" metal cations into their cryptates. The application of the Derjaguin-Landau-Verwey-Overbeek theory allowed for evaluation of the Hamaker constant of the C70-C70 interaction in vacuum, AFF, which lies in the interval of 5.8-16.6 × 10-20 J. Such an estimate, close to that made previously for C60 organosols, was received after withdrawing electrolytic systems where the hetero- and mutual coagulation were highly likely. However, it is impossible to completely exclude the interfering influence of the latter phenomena. Based on the obtained AFF values, two approaches to understanding the behavior of fullerenes in water were proposed.

Nitrosonium and Nitronium Salts of New Mixed‐Cation Hexafluoridoantimonates(V)

AbstractReaction between NOSbF6 and Cu(SbF6)2 in aHF yielded NOCu(SbF6)3. In the presence of H3OSbF6, single crystals of (H3O)0.2(NO)0.8Cu(SbF6)3 were grown from a saturated aHF solution. Both salts are isotypic and crystallize in the orthorhombic space group Pnma (No. 62) at 200 K. The main feature of their crystal structures are rings of CuF6 octahedra sharing apexes with SbF6 octahedra connected into 3‐D network. Single charged cations are located inside the cavities. Reaction between 0.25NOSbF6, 0.75NO2SbF6 and Cu(SbF6)2 in aHF yielded (NO)0.25(NO2)0.75Cu(SbF6)3 upon the crystallization. It crystallizes in the cubic space group Im (No. 204) at 200 K. Subsequent experiments with M(SbF6)2 (M=Cu, Zn) showed that, when the NO+ cations are partially or completely replaced by H3O+, the grown crystals of (H3O)0.125(NO)0.125(NO2)0.75Zn(SbF6)3 and (H3O)0.25(NO2)0.75M(SbF6)3 (M=Cu, Zn) are isotypic to (NO)0.25(NO2)0.75Cu(SbF6)3. Crystal structure of the latter demonstrates similar 3‐D structural motif as observed for the NOCu(SbF6)3 salt. The crystal structures of (H3O)0.64(NO2)0.36CuF(SbF6)2 and [Cu(H2O)6](SbF6)2 were also determined. Crystallizations of NOSbF6/O2SbF6 were carried out in aHF in different molar ratios. The crystal structure determinations of grown single crystals showed that they have the composition (NO)x(O2)1‐xSbF6 (x=0.17, 0.55 0.75) indicating that most likely all phases with x=0–1 exist. They are isotypic to NOSbF6.

Permselectivity of Cation Exchange Membranes Modified by Polyaniline.

This work discusses the applicability of polyaniline-modified cation exchange membranes for the separation of monovalent/divalent cations by electrodialysis. A novel method of membrane modification directly in the electrodialysis unit is used to prepare permselective membranes. Complex characterization of the membranes before and after modification allows revealing the influence of membrane matrix on the modification efficiency. The characterization of the membranes includes determination of the diffusion permeability, specific conductivity and current–voltage curves in HCl, NaCl and CaCl2 solutions, as well as transport-structural parameters of the extended three-wire model. The characterization results are used to predict the influence of the modification on membrane permselectivity. The competitive mass transfer of singly and doubly charged cations in the electrodialysis process is investigated in underlimiting and overlimiting currents. Electrodialysis desalination of a solution containing Na+/Ca2+ or H+/Ca2+ cations shows that the modification leads to an increase in membrane permselectivity to single-charged cations due to the repulsion of Ca2+ ions from the positively charged membrane surface. The permselectivity of the polyaniline-modified perfluorinated membrane to H+ in the mixture of H+/Ca2+ cations is observed in all current regimes.

Attempted syntheses of new mixed-cation hexafluoridoarsenates(V) in liquid anhydrous HF acidified with AsF5; the crystal structures of A3M(HF)Mn(AsF6)7 (A = H3O, K/H3O; M = Ca, Sr, Ba)

A study of the reactions between the various starting molar ratios of H3OAsF6, and in situ prepared M(AsF6)2 (M = Mg, Ca, Sr, Ba) and Mn(AsF6)2 in liquid anhydrous hydrogen fluoride (aHF) acidified with AsF5 resulted in three novel oxonium salts, i.e. (H3O)3M(HF)Mn(AsF6)7 (M = Ca, Sr) and (H3O)5BaMn(AsF6)9. Reactions between in situ prepared AAsF6 (A = K, NH4), M(AsF6)2 (M = Ca, Sr, Ba) and M’(AsF6)2 (M’ = Mn, Mg, Ni, Co, Zn) in aHF acidified with AsF5 gave mixtures of various products upon crystallization. An attempt to grow single crystals of K3Ba(HF)Mn(AsF6)7 resulted in (H3O/K)3Ba(HF)Mn(AsF6)7 instead, due to moisture penetrating through the reaction vessel walls during long lasting crystallization. The crystal structures of A3M(HF)Mn(AsF6)7 (A = H3O for M = Ca and Sr; A = H3O/K for M = Ba) salts are isotypical and crystallize in the monoclinic space group P21/n (No. 14). The crystal structures consist of a complex three-dimensional framework formed from M2+ (M = Ca, Sr, Ba) and Mn2+ cations interconnected with [AsF6]– anions. The HF molecules are bound directly to alkaline earth metals via the fluorine atom. Single charged cations are located within the cavities. The Mn atoms are found in an octahedral coordination of six fluorine atoms. The Ca atoms are coordinated by eight fluorine atoms, while this number increases to nine for the Sr and Ba atoms.

Crystal structures of isotypic ASb2F11 (A = Rb+, Tl+, O2+) and β-NH4Sb2F11, and the crystal structure of the low-temperature α-NH4Sb2F11

The crystal structures of RbSb2F11, TlSb2F11, O2Sb2F11 and β-NH4Sb2F11 salts are isotypical and crystallize in the orthorhombic space group Cmc21 (No. 36). Crystal data of rubidium salt: a = 19.9981(3) Å, b = 11.5093(2) Å, c = 12.9623(2) Å, V = 2983.46(8) Å3, and Z = 12 at 150 K. Unit cell parameters of corresponding thallium salt: a = 19.9876(5) Å, b = 11.5400(3) Å, c = 13.0267(3) Å, V = 3004.70(13) Å3 and Z = 12 at 150 K. Reaction between NH4F and excess of SbF5 in anhydrous HF resulted in the single-crystal growth of β-NH4Sb2F11: a = 20.0406(7) Å, b = 11.5534(4) Å, c = 13.0796(4) Å, V = 3028.42(18) Å3, and Z = 12 at 296 K. The XRD experiments on NH4Sb2F11 at 240 and 150 K revealed another modification (α-NH4Sb2F11), which crystallizes in a (pseudo-hexagonal) monoclinic cell, space group P21, a = 11.5045(6) Å, b = 13.0437(3) Å, c = 11.5264(6) Å, β = 119.818(7)°, V = 1500.67(15) Å3, and Z = 6 at 240 K. Reaction between the O2SbF6 and SbF5 in anhydrous HF yielded O2Sb2F11 upon crystallization with a = 19.8472(5) Å, b = 11.1172(3) Å, c = 12.8259(3) Å, V = 2829.97(12) Å3, and Z = 12 at 150 K. The crystal structures of ASb2F11 (A = Rb+, Tl+, O2+, NH4+) salts consist of dimeric Sb2F11− anions with partially disordered terminal fluorine atoms. Negative charge of the anions is compensated by single charged cations. Crystal structure of α-NH4Sb2F11 demonstrates similar motif as in β-phase but with slightly re-arranged N―H… F hydrogen bonds. In the 100−296 K range, only rhombohedral phase was observed for NH4SbF6 (rhombohedral space group R3¯, No. 148) with a = b = 7.5961(9) Å, c = 7.7176(9) Å, α = β = 90°, γ = 120°, V = 385.65(12) Å3, and Z = 3 at 150 K).

СИНТЕЗ И СТРУКТУРА КОМПЛЕКСА ПАЛЛАДИЯ (II) С 2-ЭТИЛ, - 6 МЕТИЛ - 3 - ГИДРОКСИПИРИДИНОМ

New complex compounds of palladium (II) with biologically active ligand 2-ethyl6 methyl-3-hydroxy-pyridine-mexidol in acidic medium (pH=5.3) of the following composition have been synthesized – 8 12 2 4 (C H ON) PdCl ⊕     . In this case, the ligand is protonated and as a single-charged cation occupies an external coordination sphere. The structure of the complex is proved by X-ray structure analysis. It is shown that the structure is constructed of an isolated complex anion – [PdCl4]2- and cation C H ON 8 12 ⊕ . The square planar coordination of the palladium atom is formed from three chlorine atoms and the formed tetraacidoanion ligand forms a hydrogen bond. The average length of Pd-Cl bond is 2.3030 0 A, there are no deviations from 900 valence angles of Cl-Pd-Cl. The palladium atom is not shifted from the plane coordination polyhedron (square) and therefore trance angles of Cl-Pd-Cl are 1800. Two different lengths -2.289 0 A and 2.713 0 A of hydrogen bonds are related to the geometric location of the ligand functional group. The obtained 2-ethyl-6-methyl-3-hydroxypyridinetrachloro - palladium - mexidazole was tested for radioprotective properties. Toxicity of the preparation is LD50 - 240 mg/kg of animal weight. Toxicological studies of mexidazole in mice, rats and dogs did not reveal cardiotoxic, immunotoxic, embryonic, nephrotoxic, hematoxic and other types of side effects. Mexidazole is removed from the body with urine 5-8 hours after intravenous injection. The carried out biological test showed that the compound, along with radioprotective properties, has some antitumor activity.

Removal of radionuclides, macrocomponent metal ions, and organic compounds from solutions by nanofiltration

Removal of Mg2+, Сa2+, Cu2+, Ni2+, Zn2+, Fe3+, and Pr3+ ions, tracer amounts of 137Cs, 85Sr, and 60Co radionuclides, and oxalate and ethylenediaminetetraacetate ions from solutions using a polymeric nanofiltration (NF) membrane produced by RM Nanotekh (Russia) was studied. The selectivity (S) of the NF membrane to multicharged metal cations is considerably higher than to single-charged cations. The NF membrane exhibits the highest selectivity (S = 94–97%) to triple-charged Fe3+ and Pr3+ ions and double-charged Cu2+ ions. The selectivity to double-charged Mg2+ and Zn2+ ions is somewhat lower (90–94% on the average). Among doublecharged cations, the NF membrane exhibits the lowest selectivity (80–88%) to Ni2+ and Cа2+ ions. The NF membrane shows high performance in retention of tracer amounts of Sr (S = 95%) and Co (S > 99%) radionuclides, and also of oxalate (S = 94.5%) and ethylenediaminetetraacetate (S = 97.5%) ions. Examples of using the nanofiltration method for removing 60Co from a model solution simulating NPP bottom residue and for removing transition metal impurities from a LiCl solution are presented.

Charge- and Size-Selective Ion Sieving Through Ti3C2Tx MXene Membranes.

Nanometer-thin sheets of 2D Ti3C2Tx (MXene) have been assembled into freestanding or supported membranes for the charge- and size-selective rejection of ions and molecules. MXene membranes with controllable thicknesses ranging from hundreds of nanometers to several micrometers exhibited flexibility, high mechanical strength, hydrophilic surfaces, and electrical conductivity that render them promising for separation applications. Micrometer-thick MXene membranes demonstrated ultrafast water flux of 37.4 L/(Bar·h·m(2)) and differential sieving of salts depending on both the hydration radius and charge of the ions. Cations with a larger charge and hydration radii smaller than the interlayer spacing of MXene (∼6 Å) demonstrate an order of magnitude slower permeation compared to single-charged cations. Our findings may open a door for developing efficient and highly selective separation membranes from 2D carbides.

Tri-μ-chlorido-bis-[(η(5)-penta-methyl-cyclo-penta-dien-yl)rhodium(III)] hexa-fluorido-phosphate from synchrotron radiation.

In the title complex salt, [{(η5-C5Me5)Rh}2(μ-Cl)3]PF6, the dinuclear, single-charged cation is formed by the cojoining of two classic (η5-C5Me5)RhCl3 ‘piano-stool’ units by bridging of the three choride ligand ‘legs’. The crystal structure shows several close H⋯F contacts between the hexa­fluorido­phosphate counter-ions and the C5Me5 ligands.

Influence of the concentrations of potassium, sodium, and ammonium ions on the cesium sorption with mixed nickel potassium ferrocyanide sorbent based on hydrated titanium dioxide

The effect of single-charged cations (Na+, K+, NH +4 ) on the cesium sorption with mixed nickel potassium ferrocyanide sorbent based on hydrated TiO2 was studied. The K+ and Na+ ions exert no effect at their concentrations of up to 0.5 M; the Cs+ distribution coefficients from KCl and NaCl solutions are (1.1 ± 0.5) × 105 and (8 ± 3) × 104 mL g−1, respectively. The sorbent is highly specific to Cs+ in the presence of ammonium ions. The sorption mechanisms were studied. The concentration ranges in which Cs+ and NH +4 are sorbed by independent mechanisms (Cs+, by the ferrocyanide phase; NH +4 , by the phase of hydrated TiO2) and in which the Cs+ distribution coefficient decreases owing to competitive filling of the ferrocyanide phase with ammonium ions were determined. At cesium concentrations in solution exceeding 50 mg L−1, Cs+ and NH +4 are absorbed jointly owing to coprecipitation in the mixed ferrocyanide phase in the pore space of the sorbent.

Crystal Growth and First Crystallographic Characterization of Mixed Uranium(IV)–Plutonium(III) Oxalates

The mixed-actinide uranium(IV)-plutonium(III) oxalate single crystals (NH4)0.5[Pu(III)0.5U(IV)0.5(C2O4)2·H2O]·nH2O (1) and (NH4)2.7Pu(III)0.7U(IV)1.3(C2O4)5·nH2O (2) have been prepared by the diffusion of different ions through membranes separating compartments of a triple cell. UV-vis, Raman, and thermal ionization mass spectrometry analyses demonstrate the presence of both uranium and plutonium metal cations with conservation of the initial oxidation state, U(IV) and Pu(III), and the formation of mixed-valence, mixed-actinide oxalate compounds. The structure of 1 and an average structure of 2 were determined by single-crystal X-ray diffraction and were solved by direct methods and Fourier difference techniques. Compounds 1 and 2 are the first mixed uranium(IV)-plutonium(III) compounds to be structurally characterized by single-crystal X-ray diffraction. The structure of 1, space group P4/n, a = 8.8558(3) Å, b = 7.8963(2) Å, Z = 2, consists of layers formed by four-membered rings of the two actinide metals occupying the same crystallographic site connected through oxalate ions. The actinide atoms are nine-coordinated by oxygen atoms from four bidentate oxalate ligands and one water molecule, which alternates up and down the layer. The single-charged cations and nonbonded water molecules are disordered in the same crystallographic site. For compound 2, an average structure has been determined in space group P6/mmm with a = 11.158(2) Å and c = 6.400(1) Å. The honeycomb-like framework [Pu(III)0.7U(IV)1.3(C2O4)5](2.7-) results from a three-dimensional arrangement of mixed (U0.65Pu0.35)O10 polyhedra connected by five bis-bidentate μ(2)-oxalate ions in a trigonal-bipyramidal configuration.

Supramolecular interactions in the structures of carboxylate derivatives of cymantrene and single-charged cations

The ability of cymantrenecarboxylate derivatives to form supramolecular structures has been studied for ten newly prepared derivatives of cymantrenecarboxylic acid (η5-C5H4COOH)Mn(CO)3 and two new derivatives of β-cymantrenoylpropionic acid (η5-C5H4CO(CH2)2COOH)Mn(CO)3 with cations of alkaline metals and protonated polytopic nitrogen bases of various geometries. It has been shown that structures of this kind (two- and three-dimensional) are formed owing to specific properties of the cymantrene moiety, i.e., its ability to coordinate metal ions via CO groups (to form isocarbonyl bridges) and to form CO⋯H hydrogen bonds, but in most of the cases the type of the structure is determined by the cation. In case of Li cymantrenecarboxylate complex the formation of hexameric molecules having a cavity was found. The crystal and molecular structure of cymantrenecarboxylic acid has been described for the first time.

Anodic synthesis of Np(VII) compounds from acetate solutions

A procedure was suggested for the synthesis of Np(VII) compounds by electrochemical oxidation in acetate solutions. The conditions for preparing compounds of type MNpO4·nH2O, where M is a single-charged cation of alkali metals, ammonium, silver, guanidinium, or tetraalkylammonium, and of Np(VII) compounds with double-charged cations of alkaline-earth metals, Cu, Cd, and Zn were studied in detail. The compounds were characterized by chemical analysis and by IR and electronic spectroscopy.

Ion-exchange equilibriums involving single-charged cations on saponite

We have investigated the ion-exchange sorption of cations of alkaline metals on saponite at the constant and varied ionic force. We have determined a selectivity series of exchange centers of saponite with respect to these cations. It has been shown that the exchange centers on the saponite surface are unequal in terms of energy. When using the Langmuir equation two types of energy centers sharply different by energy; these centers were referred to specific sections of the saponite structure.

Collision-induced dissociation of singly and doubly charged CuII–cytidine complexes in the gas phase: an experimental and computational study

The complexes of doubly charged cations, [CuLn]2+, [CuL(MeOH)n]2+ and single charged cations, [Cu(L–H)Ln]+, [L+H]+, [L2+H]+, and [B+H]+, etc. (L = cytidine, B = cytosine) were observed via electrospray of water and methanol solutions of Cu(NO3)2 and cytidine. The peak distribution for [CuLn]2+ shows that the [CuL2]2+ and [CuL4]2+ are the highest peaks, then followed by [CuL3]2+, [CuL5]2+, etc.Collision-induced dissociation (CID) of [Cu(L–H)Ln]+(n = 0,1), [CuLn]2+(n = 2–6) and [CuL(MeOH)n]2+(n = 1, 2) was investigated using the ESI-MS/MS instrument, and the structure and thermal energy for the most of these complexes were also calculated with ab initio and DFT methods through Gaussian 09 program. For [Cu(L–H)L0-1]+, the primary dissociation only involved a ribose group, including ribose group lost, ribose side chain and ribose ring broken. The calculation result shows that the deprotonated site for [Cu(L–H)]+ is the N-atom in the amino group of the cytidine base. The inter-ligand proton transfer was observed to dominate the CID of all doubly charged CuII–cytidine complexes, [CuLn]2+ (n = 2–6), and other channels, including charge reduction dissociation, lost neutral ligands were also observed. The protonated cytidine dimer, [L2+H]+, produced in the CID of [CuLn]2+ (n = 4–6), can further break into [L+ H]+ and neutral L, and the structure is proposed to be from the interaction of two cytidinesviahydrogen bonds. The protonated trimeric cytidine was also observed in the dissociation of [CuL6]2+. Three charge reduction dissociation channels were observed in the CID of [CuL(MeOH)]2+. Unlike the CuII–guanosine complex, the radical cation [CuLn]+ was not observed in the CID process of the [CuLn]2+, and the reasons are attributed to the higher ionization energy and proton affinity, which makes the inter-ligand proton transfer more favorable than the electron transfer from ligand to Cu2+.