DMF Ligands Research Articles

Strong CO2 Binding in a Water-Stable, Triazolate-Bridged Metal−Organic Framework Functionalized with Ethylenediamine

Reaction of CuCl(2) x 2 H(2)O with 1,3,5-tris(1H-1,2,3-triazol-5-yl)benzene (H(3)BTTri) in DMF at 100 degrees C generates the metal-organic framework H(3)[(Cu(4)Cl)(3)(BTTri)(8)(DMF)(12)] x 7 DMF x 76 H(2)O (1-DMF). The sodalite-type structure of the framework consists of BTTri(3-)-linked [Cu(4)Cl](7+) square clusters in which each Cu(II) center has a terminal DMF ligand directed toward the interior of a large pore. The framework exhibits a high thermal stability of up to 270 degrees C, as well as exceptional chemical stability in air, boiling water, and acidic media. Following exchange of the guest solvent and bound DMF molecules for methanol to give 1-MeOH, complete desolvation of the framework at 180 degrees C generated H(3)[(Cu(4)Cl)(3)(BTTri)(8)] (1) with exposed Cu(II) sites on its surface. Following a previously reported protocol, ethylenediamine molecules were grafted onto these sites to afford 1-en, featuring terminal alkylamine groups. The N(2) adsorption isotherms indicate a reduction in the BET surface area from 1770 to 345 m(2)/g following grafting. The H(2) adsorption data at 77 K for 1 indicate a fully reversible uptake of 1.2 wt % at 1.2 bar, while the CO(2) isotherm at 195 K shows a maximal uptake of 90 wt % at 1 bar. Compared to 1, the alkylamine-functionalized framework 1-en exhibits a higher uptake of CO(2) at 298 K and pressures up to ca. 0.1 bar, as well as a higher CO(2)/N(2) selectivity at all measured pressures. Significantly, 1-en also exhibits an isosteric heat of CO(2) adsorption of 90 kJ/mol, which is much higher than the 21 kJ/mol observed for 1. This chemisorption interaction is the strongest reported to date for a metal-organic framework and points toward the potential utility of alkylamine-appended frameworks for the postcombustion capture of CO(2) from low-pressure flue gas streams.

Synthesis, structure and magnetic property of the first 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands

Abstract An unprecedented 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands [DMAH]4{[Mn(DMF)4]2[Mn4(DMF)2(α-B-HPW9O34)2]} (1) (DMA = dimethylamine, DMF = N,N-dimethylformamide) has been solvothermally synthesized and characterized by IR, UV spectra and X-ray single-crystal diffraction. The 2-D organic–inorganic hybrid network of 1 is built by tetra-MnII substituted sandwich-type polyoxotungstates [Mn4(DMF)2(α-B-HPW9O34)2]8− and [Mn(DMF)4]2+ cation bridges, which displays the common 2-D (4,4) topological net. It should be noted that the major difference between [Mn4(DMF)2(α-B-HPW9O34)2]8− in 1 and the reported [Mn4(H2O)2(α-B-PW9O34)2]10− is that two DMF ligands substitute two H2O ligands on the Mn4O16 unit located in the sandwich belt. Magnetic susceptibility measurement indicates the occurrence of antiferromagnetic coupling interaction within MnII ions.

Lanthanide complexes in hybrid halometallate materials: interconversion between a novel 2D microporous framework and a 1D zigzag chain structure of iodoargentates templated by octakis-solvated terbium(III) cation

Octakis solvated terbium iodide complexes [Tb(DMSO)(8)]I(3) (1) and [Tb(DMF)(8)]I(3) (2) (DMSO = dimethylsulfoxide; DMF = dimethylformamide) were used as synthons to construct novel iodoargentate fabrics. Reaction of 1 with 6 equivalents of AgI in the presence of NH(4)I produced a novel framework compound [Tb(DMSO)(8)](2)[Ag(2)(mu-I)(3)I(2)][Ag(5)(mu(3)-I)(4)(mu-I)(4)](2infinity) (3) involving alternate layers of discrete [Tb(DMSO)(8)](3+) cation, [Ag(2)I(5)](3-) anion and a 2D microporous sheet of the composition [Ag(5)I(8)](3-), whereas similar reaction of 2 yielded [Tb(DMF)(8)][Ag(6)(mu(4)-I)(2)(mu(3)-I)(2)(mu-I)(5)](1infinity) (4) with a 1D zigzag structure. The two structural forms are completely inter-convertible on mutual exchange of DMSO and DMF ligands, the partial substitution of the former ligand in 3 yielding a mixed-ligand complex [Tb(DMF)(6.7)(DMSO)(1.3)][Ag(6)(mu(4)-I)(2)(mu(3)-I)(2)(mu-I)(5)](1infinity) (5). Single crystal X-ray structures are reported for all the complexes. Thermo-gravimetric analyses of these complexes show that thermal stability decreases in the order 4 > 2 > 3 > 1, whereas the diffuse reflectance spectra of 3 and 4 exhibit an optical band gap of about 3.7 eV, thus revealing the insulator nature of these hybrid iodoargentates. Compared to solvated terbium iodide complexes 1 and 2, the high energy transitions in the excitation spectra of the iodoargentate complexes 3 and 4 are quenched by a process which can best be attributed to the auto-ionization of the carriers in the above materials.

Microwave-assisted synthesis of quinazolinone derivatives by efficient and rapid iron-catalyzed cyclization in water

A green, rapid, and efficient method was developed for synthesizing quinazolinone derivatives from substituted 2-halobenzoic acids and amidines via microwave-assisted iron-catalyzed cyclization with or without ligand in water (methods A and B) or DMF (methods C and D). With these methods, moderate to high yields of the desired products can be obtained from even inactive substrates, such as guanidines. To the best of our knowledge, this is the first report on the synthesis of N-heterocyclic compounds by iron-catalyzed C–N coupling in aqueous media.

Dimeric versus monomeric nickel(II) complexes with tetraorganodichalcogenoimidodiphosphinato ligands: Crystal structures of Ni 2[(OPPh 2) 2N] 4 · CH 2Cl 2, Ni[(OPPh 2) 2N] 2(DMF) 2 · 2H 2O and [KNi[(SPPh 2){OP(OEt) 2}N] 3] 2

Nickel(II) complexes of the type Ni [ ( XPR 2 ) ( YPR 2 ′ ) N ] 2 [X = S ( 1) or O ( 2), Y = O, R = Ph, R′ = OEt] and Ni 2[(OPPh 2) 2N] 4 ( 3) were prepared by reacting either anhydrous NiCl 2 or NiCl 2 · 6H 2O with the potassium salt of the appropriate tetraorganodichalcogenoimidodiphosphinic acid, in 1:2 molar ratio. Recrystallization of 3 from dimethylformamide resulted in Ni[(OPPh 2) 2N] 2(DMF) ( 4). Reaction between NiCl 2 and K[(SPPh 2){OP(OEt) 2}N] in an 1:3 molar ratio resulted in the ionic species KNi[(SPPh 2){OP(OEt) 2}N] 3 ( 5). Compounds 1– 5 were characterized by IR, electronic spectroscopy and mass spectrometry. The molecular structures of 3 · CH 2Cl 2, 4 · 2H 2O and 5 were determined by single-crystal X-ray diffraction. A dimeric structure was found in case of complex 3 · CH 2Cl 2, with both monometallic biconnective and homobimetallic triconnective [(OPPh 2) 2N] − units, while an octahedral environment around nickel was established in the monomeric complex 4 · 2H 2O by monometallic biconnective [(OPPh 2) 2N] − and DMF ligands, respectively. The crystal of the ionic species 5 contains discrete tetranuclear units in which the phosphorus ligands act heterobimetallic, either ( O, O, S)-triconnective or ( S, O, O, O Et)-tetraconnective, and ( N, O, O, S)-heterotrimetallic tetraconnective, resulting in an octahedral environment around nickel and a square-pyramidal one around potassium, respectively. Powder X-ray diffraction studies on 5 are in agreement with the single-crystal investigation.

Synthesis and Characterization of Two Linear Fe‐M‐S Clusters Coordinated by Bis(pyrid‐2‐ylmethyl)amine(BPA): [(BPA)(DMF)FeS2MS2] (M = Mo, W)

AbstractTwo heterometallic linear clusters [(BPA)Fe(DMF)S2MoS2] (1), and [(BPA)Fe(DMF)S2WS2] (2) have been synthesized and characterized by X‐ray crystallography and infrared spectra. X‐ray crystallography reveals that they are isostructural with each other. The iron atoms are six coordinated in distorted octahedral N3S2O coordination. The bond lengths of Fe‐Mo [2.8441(7) Å] and Fe‐W [2.8767(10) Å] are longer than normal values in Fe‐M‐S clusters containing the FeS2MoS2 core. The obviously long Fe‐O bond lengths in 1 and 2 indicate loose coordination for DMF ligands. There exist oppositely aligned dimers bridged by intermolecular S···S interactions in both two crystal structures, which relinked by N–H···S and C–H···S hydrogen bonding interactions into layers, π‐π stacking interactions provide the linkage between neighbouring layers, giving rise to the whole crystal structures.

Synthesis and characterization of two new β-octamolybdate complexes [NH4][Y(DMF)5(H2O)3][Mo8O26]·2CH3CN and [NH4][Ce(DMF)7Mo8O26

Two new β-octamolybdate supported metal complexes [NH4][Y(DMF)5(H2O)3][Mo8O26] · 2CH3CN (1) and [NH4][Ce(DMF)7Mo8O26] (2) have been synthesized in mixed water and acetonitrile by reaction of (NH4)6Mo7O24 · 4H2O with MCl3 (M3+ = Y for 1 and Ce for 2), DMF (DMF = N,N-Dimethylformamide) and characterized by elemental analysis, IR spectra, TG analysis, and single-crystal X-ray structural analysis. The single crystal X-ray diffraction analysis reveals that compound 1 consists of discrete [NH4][Y(DMF)5(H2O)3][Mo8O26] · 2CH3CN, constructed from β-octamolybdate subunits [Mo8O26]4−, ammonium cations, [Y(DMF)5(H2O)3]3+ cations and two acetonitrile molecules of crystallization. Y3+ is eight-coordinate with five DMF ligands and three water molecules. Compound 2 is built up from DMF coordinated CeIII fragment and β-octamolybdate units joined together via two terminal oxygen atoms of two molybdenum atoms.

Synthesis and characterization of one- and two-dimensional octacyanometalate(V) networks: {[ trans-M II(DMF) 4][ cis-M II(DMF) 4] 2[M V(CN) 8] 2} n (M II = Mn, Fe, Ni; M V = Mo, W)

Treatment of several binary transition metal p-toluenesulfonates [M II(OTs) 2] with tri(butyl)ammonium octacyanomolybdate(V) or -tungstate(V) in DMF readily affords a series of one- and two-dimensional crystalline octacyanometalate networks of [M II(DMF) 4] 3[M V(CN) 8] 2 (M V = Mo, W; M II = Mn, 5, 6; Ni, 7, 8) stoichiometry. Treatment of Fe(OTs) 2 with [HBu 3N] 3[W V(CN) 8] in DMF affords amorphous precipitates while FeCl 3 affords crystalline [Fe II(DMF) 6] 2[W IV(CN) 8] ( 9) salts; two-dimensional [Fe II(DMF) 4] 3[W V(CN) 8] 2 ( 10) lattices are obtained from 9 after standing several months. The structures of 5 and 8 contain [ cis-M II(DMF) 4(μ-NC) 2] 2+ and [ trans-M II(DMF) 4(μ-NC) 2] 2+ units that are linked via cyanides to three-connected [M V(CN) 5(μ-CN) 3] 3− centers, forming a one-dimensional chain of { M 2 II ( μ -CN ) 4 M 2 V } squares that crystallize in the monoclinic ( 5, P2 1/ n) and triclinic ( 8, P 1 ¯ ) space groups; 6 ( P2 1/ n) and 10 ( P2 1/ c) crystallize as two-dimensional corrugated sheets containing [ cis-M II(DMF) 4(μ-NC) 2] 2+, [ trans-M II(DMF) 4(μ-NC) 2] 2+, and [M V(CN) 5(μ-CN) 3] 3− units in a 4:2:6 ratio. Magnetic measurements indicate that 6 is a ferrimagnet ( T N = 8 K) that exhibits frequency-dependent behavior in χ″ that is qualitatively similar to 1- and 2-D lattices reported by Tang and Holmes, respectively; dc magnetic measurements suggest that 5, 7, and 8 exhibit incipient magnetic ordering while ac measurements show no frequency-dependent behavior in χ″. Surprisingly, conversion of 5 to 6 in the presence of counterions occurs while heating crystalline samples introduces additional magnetic phases without linkage isomerism; two-dimensional phases containing Mn II centers appear to be the sole product when wet DMF is used as a reaction solvent. The experimental evidence suggests that coordinated DMF ligands are labile and the M II(μ-NC)M V linkages are susceptible to fragmentation.

X-ray Diffraction, PGSE Diffusion, and Related NMR Studies on a Series of Cp*-Based Ru(IV)(Cp*)(η3-CH2−CH−CHPh) Allyl Complexes

The new ruthenium (IV) allyl complexes [Ru(Cp*)Cl(DMF)(η3-CH2−CH−CHPh)](PF6) (2b) and [Ru(Cp*)Cl(t-BuCN)(η3-CH2−CH−CHPh)](PF6) (2c) have been prepared and their structures determined. These results are compared with the analogous X-ray data for [Ru(Cp*)Cl(CH3CN)(η3-CH2−CH−CHPh)](PF6), [Ru(Cp*){OC(O-t-Bu)O}(η3-CH2−CH−CHPh)](PF6), [Ru(Cp*)(CH3CN)2(η3-CH2−CH−CHPh)](PF6)2, and [Ru(Cp*)(DMF)2(η3-CH2−CH−CHPh)](PF6)2. In all of the structures, the Ru−((η3-CH2−CH−CHPh) moiety is markedly distorted such that Ru−CPh(allyl) separation is much longer than the remaining two Ru−C(allyl) distances. The DMF and acetonitrile ligands are shown to exchange on the NMR time scale via both variable-temperature and 2-D exchange spectroscopy. Pulsed gradient spin−echo (PGSE) diffusion and 1H,19F HOESY NMR methods show that there is relatively little ion pairing in these salts in DMF and acetonitrile solutions. The PF6 anions take up specific positions with respect to the Ru(IV) cations.

First characterization of an uranium(III) complex with a carbonyl-containing ligand: Syntheses and X-ray crystal structures of the homoleptic dimethylformamide complexes [M(dmf) n]I 3 (M = Ce, Nd and n = 8; M = La, Ce, U and n = 9)

Solutions of the trivalent iodides LnI 3 and [UI 3(py) 4] in dimethylformamide (dmf) deposited crystals of the tricationic species [M(dmf) n ]I 3 (M = Ce ( 1), Nd ( 2) and n = 8; M = La ( 3), Ce ( 4), U ( 5) and n = 9). The dmf ligands are labile and easily removed under vacuum affording solid samples of [MI 3(dmf) n ] compounds with varying numbers of coordinated dmf molecules ( n = 2–6). The uranium derivative was oxidized into [U(dmf) 9]I 4 in dmf at 110 °C. X-ray crystal structures of complexes 1– 5 show the differences between the U–O and Ln–O distances to reflect the variation in the ionic radii of the metals, demonstrating the similar nature of the [M]–O C interaction in these series of 4f- and 5f-elements.

Catena-Poly[[bis(N,N-dimethylformamide-κO)nickel(II)]-di-μ-1,5-dicyanamido-κN1:κN5

In the crystal structure of the title complex, [Ni(C2N3)2(C3H7NO)2]n or [Ni(dca)2(DMF)2]n, where dca is dicyanamide and DMF is N,N-dimethyl­formamide, each NiII atom is six-coordinated in a distorted octa­hedral coordination environment. Four N atoms from four dca ligands fill the equatorial positions, and two O atoms from two DMF ligands fill the axial positions. The structure is isostructural with [Co(dca)2(DMF)2]n but is not isostructural with [Mn(dca)2(DMF)2]n. The NiII atom and the dicyanamide bridging ligand occupy special positions of symmetry 2/m and m, respectively. The structure consists of uniform neutral chains where neighbouring NiII atoms are connected through two asymmetric end-to-end dca bridges.

Polynuclear nickel (II) and copper (II) complexes of hexaazamacrocycles incorporating pairs of diethylenetriamine subunits separated by aromatic spacers

A series of Ni(II) and Cu(II) complexes of the hexaaza macrocycles, 3,6,9,17,20,23-hexaazatricyclo[23.3.1.1 11,15]triaconta-1(29),11(30),12,14,25,27-hexaene (L 1) and 3,6,9,16,19,22-hexaazatricyclo[22.2.2.2 11,14]triaconta-1(26),11(29),12,14(30),24(28),25-hexaene (L 2), have been prepared and the crystal structures determined for [Ni 2L 1(O 2CCH 3) 2(H 2O) 2](ClO 4) 2 ( 1), [Ni 2L 2(DMF) 6](ClO 4) 4 · 2H 2O ( 2), {[Cu 2L 2Br(O 2CCH 3)](ClO 4) 2} n ( 3), [Cu 2L 2(μ-CO 3)(H 2O) 2] 2(ClO 4) 4 · 8H 2O ( 4), [Cu 2L 2(O 2CCH 3) 2](BF 4) 2 ( 5), and [Cu 2L 1(μ-imidazolate)Br] 2Br 4 · 6H 2O ( 6). In these complexes, two metal centers are bound per ligand; in 1 and 3– 6, the N 3 subunits of L 1 or L 2 coordinate meridionally to the metal centers, whilst in 2, each N 3 subunit in L 2 adopts a facial mode of coordination. The binuclear cations in 1 and 2 have chair-like conformations, with the distorted octahedral Ni(II) coordination spheres completed by terminal water and a bidentate acetate ligand in 1 and three DMF ligands in 2. The Cu(II) centers in 3– 6 generally reside in square planar environments, although a weakly binding ligand enters the coordination sphere in some cases, generating a distorted square pyramidal geometry. The binuclear [Cu 2L 2] 4+ units in 3, 4 and 5 adopt similar bowl-shaped conformations, stabilized by H-bonding interactions between pairs of amine groups from L 2 and a perchlorate or tetrafluoroborate anion. In 3, the binuclear units are linked through acetate groups, bridging in a syn- anti fashion, to produce a zig-zag polymeric chain structure, whilst 4 incorporates a tetrameric cation consisting of two binuclear units linked via a pair of carbonate bridges. Compound 6 features an imidazolate bridge between the two Cu(II) centers bound by L 1. Pairs of [Cu 2L 1(μ-imidazolate)] 3+ units are then weakly linked through a pair of bromide anions.

New manganese complexes with 2-salicyloylhydrazono-1,3-dithiolane ligand and various coordination solvents

The new Mn ( HL ) 2 L 2 ′ complexes with 2-salicyloylhydrazono-1,3-dithiolane ligand (H 2L) have been obtained with good yields (≈85%) by reacting manganese (II) acetate tetrahydrate or manganese (II) acetylacetonate with 2-salicyloylhydrazono-1,3-dithiolane ligand in DMF, THF or Py (L′). These compounds have been fully characterized by spectroscopic methods and single crystal X-ray diffraction. In the solid state, supramolecular networks are described and discussed in terms of weak H-bonds and short contacts. The new monomeric complexes will be considered as candidates to obtain polynuclear complexes.

Bis[4-benzoyl-5-methyl-2-phenyl-2H-pyrazol-3(4H)-onato-κ2O,O′]bis(N,N-dimethylformamide-κO)cadmium(II)

In the structure of the title complex, [Ni(C17H13N2O2)2(C3H7NO)2] or [Ni(PMBP)2(DMF)2], where HPMBP is 4-benzoyl-5-methyl-2-phenyl-2H-pyrazol-3(4H)-one, the CdII atom, which lies on an inversion centre, is in a distorted octa­hedral coordination environment. The metal is coordin­ated by four O atoms from the two symmetry-related chelating PMBP− ligands and O atoms from the two symmetry-related DMF ligands.

Axial Bonds in Copper(II) Cyclam with DMF Ligands

There have been many examples of copper(II) tetraazamacrocycles, where the axial donors interact with copper(II) ions. However, the complexes reported usually show considerably long Cu-axial donor distances with weak interactions between metal centers and axial donors. Even such weak interactions, it appears that the presence of hydrogen-bonding chelate rings comprised of axial donors, suitable anions and solvents, and secondary amines of the macrocycle is requisite for the stabilization of axial ligands to the central copper(II) ions. In the present work, we describe the preparation and structure of trans-[Cu(L)(DMF)2](PF6)2 (1) (L = cyclam = 1,4,8,11-tetraazacyclotetradecane, DMF = N,N-dimethylformamide), where the complex shows fairly strong copper-axial donor interactions without the support of hydrogen-bonding chelate rings.

Cadmium complexes of meso-tetra-( p-chlorophenyl)porphyrin: [ meso-tetra-( p-chlorophenyl)porphyrinato](pyridine)cadmium(II) pyridine solvate and [ meso-tetra-( p-chlorophenyl)porphyrinato](dimethylformamide)cadmium(II) toluene solvate

The crystal structures of [ meso-tetra-( p-chlorophenyl)porphyrinato](pyridine)cadmium(II) pyridine solvate Cd[( p-Cl) 4tpp](py) · py [or 5 · py], and [ meso-tetra-( p-chlorophenyl)porphyrinato](dimethylformamide)cadmium(II) toluene solvate Cd[( p-Cl) 4tpp](DMF) · toluene [or 6 · toluene] were determined. The ring current effect provides a complementary method for the investigation of coordinated pyridine and DMF ligand in complexes 5 and 6, respectively.

The 1:1 adduct of cobalt(II) terephthalate withN,N-dimethylformamide

The solvothermal reaction of cobalt(II) nitrate and terephthalic acid in N,N-di­methyl­form­amide (DMF) yields the polymeric title compound, poly­[cobalt(II)-μ2-N,N-di­methyl­form­amide-κ2O:O-μ4-terephthalato- κ4O:O′:O′′:O′′′], [Co(C8H4O4)(C3H7NO)]n. In the crystal structure, both the Co atom and the terephthalate group occupy special positions of 2/m site symmetry. The DMF ligand is located on a mirror plane with the N atom on a special position of site symmetry mm2. The octahedral coordination polyhedron around the Co atom has two opposite sites that are occupied by the O atoms of DMF mol­ecules; the other sites are occupied by the carboxyl O atoms of four different terephthalate groups. The compound adopts an open framework structure having channels in which the disordered DMF mol­ecules reside.

Bis(N,N-dimethylformamide-κO)bis[1-phenyl-3-methyl-4-benzoyl-1H-pyrazol-5(4H)-onato-κ2O,O′]nickel(II)

In the crystal structure of the title complex, [Ni(C17H13N2O2)2(C3H7NO)2] or [Ni(PMBP)2(DMF)2], where HPMBP is 1-phenyl-3-methyl-4-benzoyl-1H-pyrazol-5(4H)-one, the NiII atom, which lies on an inversion centre, is six-coordinated in a distorted octahedral coordination environment by coordinating four O atoms from two symmetry-related chelating bidentate PMBP ligands and two O atoms from two symmetry-related DMF ligands.

Syntheses and Structures of two 1-D Complexes, [Co(dmf)2(NCNCN)2] and [Cu(bipy)(NCNCN)]ClO4 with Bridging Dicyanamide Ligands

Two novel dicyanamide complexes [Co(dmf)2(NCNCN)2] (1) and [Cu(bipy)(NCNCN)]ClO4 (2) have been synthesized and structurally characterized. 1 crystallizes in the monoclinic space group C2 with a = 13.568(6)Å, b = 7.403(3)Å, c = 8.118(3)Å and Z = 2, whereas 2 crystallizes in the monoclinic system, Cc group, a = 14.270(7)Å, b = 9.143(5)Å, c = 12.371(1) Å, β = 118.612(7)°, and Z = 4. According to X-ray crystallographic studies, in complex 1 each CoII ion is six-coordinated with four nitrogen atoms from four μ1, 5-dca (dca = dicyanamide) ligands and two oxygen atoms from two dmf ligands to form distorted octahedra. 1 forms a 1-D network bridged via μ1, 5-dca. 2 consists of a uniform Cu(NCNCN)Cu chain, each CuII ion is octahedrally coordinated with four nitrogen atoms from two μ1, 5-dca ligands and one bipy ligand and two oxygen atoms from two ClO4— ions. The octahedral CuII ion shows a significant Jahn-Teller distortion, with two axial oxygen atoms considerably farther from the copper than the four equatorial nitrogens.

Gas-Phase Solvation Behavior of Ni(II) in Water/N,N-Dimethylformamide Mixtures

Electrospray ionization−mass spectrometry (ESI-MS) is used to investigate the complexation of nickel(II) by N,N-dimethylformamide (DMF) in different water/DMF mixtures. The types of solvated cations observed are independent of the solvent composition and are part of the series [Ni(DMF)n]2+ with n = 2−6 and [Ni(DMF)nX]+ with n = 1−4 (where X = Cl, Br, NO3). The number of ligands, n, and thus the extent of solvation depends on the cone voltage (UC) of the ESI source. At low UC multiply ligated ions prevail, whereas ligation drops with rising UC and further increase of UC causes dissociation of the solvent molecules as well as reduction of Ni(II) to Ni(I). The collision-induced dissociation (CID) spectra of the multiply ligated ions [Ni(DMF)n]2+ with n ≥ 3 and [Ni(DMF)nX]+ with n ≥ 2 show only losses of neutral DMF ligands. Quite different is the behavior of the bisligated ions [Ni(DMF)2]2+ and [Ni(DMF)X]+. In the CID spectrum of [Ni(DMF)2]2+, electron transfer from DMF to the metal leads to the reduced complex [Ni(DMF)]+ concomitant with ionized DMF+. Charge-stripping spectra of mass-selected monocations [Ni(DMF)n]+ (n = 1, 2) confirm that the dication [Ni(DMF)2]2+ is stable, whereas monoligated [Ni(DMF)]2+ appears to be intrinsically unstable toward Coulomb explosion. In the CID spectra of [Ni(DMF)Cl]+ and [Ni(DMF)Br]+, bond activation of the solvent takes place, and in the case of [Ni(DMF)NO3]+ the formation of a cationic species is observed which formally corresponds to the solvated metal-oxide cation [(DMF)NiO]+.