Complexation of nickel(II) by ethylenediamine investigated by means of electrospray ionization mass spectrometry

Complexation of transition metals by 3-azidopropionitrile. An electrospray ionization mass spectrometry study

“…This different behavior might be explained on the grounds of relative values of bond dissociation enthalpy of HX (X ϭ Cl, Br), which is higher for chlorine. ϩ is approximately 3% is ambiguous since it can mean either that NO 3 bridged complexes exist, against predictions ofáTsierkezosáetáal.á [54],áoráthatáitsálowáabundanceápoints to a very unstable moiety. In any case, if there are bridged complexes in NO 3 , they are probably oxo- ϩ and the release of a radical NO 2 .…”

Complexes of dichloro(ethylenediamine)palladium(II) observed from aqueous solutions by electrospray mass spectrometry

“…The mechanisms of action for these coordination complexes are closely tied to their hydrolysis products, and these products and mechanisms are poorly understood, partly due to the possibility of multiple equilibria with similar energetics [11,12]. It is for these reasons that coordination complexes of Ni(II), Pd(II), and Pt(II) in aqueous solutions have been the focus of a number of investigations [13][14][15][16][17].Electrospray mass spectrometry (ESMS) is particularly well suited for the study of metal-containing aqueous solutions, and a variety of such studies have been conducted [18,19]. We recently reported the results of one such study into aqueous solutions of dibromo(ethylenediamine)palladium(II) [20].…”

“…The mechanisms of action for these coordination complexes are closely tied to their hydrolysis products, and these products and mechanisms are poorly understood, partly due to the possibility of multiple equilibria with similar energetics [11,12]. It is for these reasons that coordination complexes of Ni(II), Pd(II), and Pt(II) in aqueous solutions have been the focus of a number of investigations [13][14][15][16][17].…”

Distinctive unimolecular gas-phase reactivity of [M(en)2]2+(M=Ni, Cu) dications and their inclusion complexes with the macrocyclic cavitand Cucurbit[8]uril

“…The gas-phase dissociation of the [Ni(en) n ] 2ϩ (n ϭ 2 to 5) species has been described by Schröder et al Ligand evaporation was observed for n ϭ 4, 5 while inter-proton transfer processes occurred for n ϭ 3. Remarkably, the gas-phase dissociation of the [Ni(en) 2 ] 2ϩ dication occurs through intra-complex electron-transfer followed by charge separation to yield exclusively the [Ni(en)] ϩ cations and the non-detected -ϩ as shown in eq 6 [18]. Our results indicate more complicated dissociation patterns for the [Ni(en) 2 ] 2ϩ dication.…”

“…One of the largest members of the cucurbit[n]uril family, cucurbit [8]uril, has proved to encapsulate cobalt, nickel, copper and zinc complexes with aliphatic polyamine ligands such as ethylenediamine, cyclam, or cyclen (cyclam ϭ 1,4,8,11-tetraazacyclotetradecane; cyclen ϭ 1,4,7,10-tetraazacyclododecane), although no gas-phase studies on the host-guest complexes have been reported so far [12][13][14][15]. This fact is in contrast with numerous gas-phase ion chemistry studies on non-encapsulated polyamine transitionmetal complexes as, for example, [M(cyclam)] 2ϩ (M ϭ Ni, Cu) [16], diethylenetriamine derivatives coordinated to copper [17], or the ethylenediamine complexes [Ni(en) n ] 2ϩ (n ϭ 2-5) [18] and [Cu(en)] ϩ [19]. In particular, the studies on the diethylenetriamine or 2,2=:6=,2=-terpyridine complexes of copper have been primarily motivated by the ability of these complexes to bind small biomolecules (such as amino acids or nucleic acids) and subsequently generate the corresponding radical cations under CID conditions [20 -23].…”