Cover Picture: Journal of the Chinese Chemical Society 4/2011

By means of ultrafast x‐ray absorption, optical spectroscopy and DFT theoretical calculation, we find that even though both molecules are excited into their charge transfer band, the redox reaction of [M(III)(C₂O₄)₃]^3‐ (M=Fe, Co) proceeds via intermolecular electron transfer while [Co(III)(NH₃)₆]³⁺ electron transfer mechanism is intramolecular. This article entitled “Electron Transfer in Metal‐Organic Molecules. A Time Resolved EXAFS and Optical Spectroscopy Study” was contributed by Prof. Peter M. Rentzepis who was invited as a Visiting Lecturer of the Chemistry Research Promotion Center, Taiwan, R.O.C. (November 12, –November 20, 2010). For full text, please see pp. 415–427 in this issue.     

Kinetics and Thermodynamics of Formation and Electron‐Transfer Reactions of Surfactant Cobalt(III) Complexes Containing Polypyridyl Ligands with Fe(CN)64− in Microheterogeneous Environment

The electron‐transfer reaction of some surfactant cobalt(III) complexes, cis‐[Co(ip)₂(C₁₂H₂₅NH₂)₂]³⁺ 1 , cis‐[Co(dpq)₂(C₁₂H₂₅NH₂)₂]³⁺ 2 , and cis‐[Co(dpqc)₂(C₁₂H₂₅NH₂)₂]³⁺ 3 (ip = imidazo[4,5‐f][1,10]phenanthroline, dpq = dipyrido[3,2‐d:2′‐3′‐f]quinoxaline, dpqc = dipyrido[3,2‐a:2′,4′‐c](6,7,8,9‐tetrahydro)phenazine, C₁₂H₂₅NH₂ = dodecylamine) with the Fe(CN)₆^4? ion has been investigated in microheterogeneous media (micelles, β‐cyclodextrin) at different temperatures by the spectrophotometric method under pseudo‐first‐order conditions using an excess of the reductant. Experimentally, the reaction was found to be second order and the electron transfer postulated as an outer sphere. The rate constant for the electron‐transfer reaction in micelles was found to increase with an increase in the initial concentration of the surfactant–cobalt(III) complex. This peculiar behavior of dependence of the second‐order rate constant on the initial concentration of one of the reactants has been attributed to the presence of various concentrations of micelles under different initial concentrations of the surfactant–cobalt(III) complex in the reaction medium. Inclusion of the long aliphatic chain of the surfactant complex ion into β‐cyclodextrin leads to decrease in the rate constant. Kinetic data and activation parameters are interpreted in terms of an outer‐sphere electron‐transfer mechanism. All these results have been interpreted in terms of the hydrophobic effect and the reactants with the opposite charge.     

(Δ)[Fe(II)(phen)3]2+ Filled in the Chiral Cavitiy Constituted by {(Δ)[Fe(III)(C2O4)3](NH42+)(DMF)(H2O)32−}n

A chiral coordination compound {(Δ)[Fe(II)(phen)₃][(Δ)Fe(III)(C₂O₄)₃](NH₄)(H₂O)₃(DMF)}_n (phen = 1,10‐phenanthroline), (DMF = N,N'‐Dimethylformamide), has been synthesized, and the structure has been revealed by infrared spectroscopy and X‐ray single‐crystal diffraction. The framework consists of two chiral subunits. One subunit (Δ)[(Fe(III)(C₂O₄)₃]^3? which as host anion forms a chiral porous three‐dimensional supermolecular network with lattice water, lattice DMF and lattice ammonium cation through hydrogen bonds. And then the other is Δ[Fe(II)(phen)₃]²⁺ which as guest cation fills in the chiral cavity located in the previously mentioned host porous network.     

Kinetics of Reduction of Some Surfactant-Cobalt(III) Complexes by Iron(II)

The electron transfer kinetics of the reaction between the surfactant-cobalt(III) complex ions, cis-[Co(en)₂(C₁₂H₂₅NH₂)₂]³⁺, cis-α-[Co(trien)(C₁₂H₂₅NH₂)₂]³⁺(en:ethylenediamine, trien:triethylenetetramine, C₁₂H₂₅NH₂ : dodecylamine) by iron(II) in aqueous solution was studied at 298, 303, 308 K by spectrophotometry method under pseudo-first-order conditions using an excess of the reductant in self-micelles formed by the oxidant, cobalt(III) complex molecules, themselves. The rate constant of the electron transfer reaction depends on the initial concentration of the surfactant cobalt(III) complexes. ΔS^# also varies with initial concentration of the surfactant cobalt(III) complexes. By assuming outer-sphere mechanism, the results have been explained based on the presence of aggregated structures containing cobalt(III) complexes at the surface of the self-micelles formed by the surfactant cobalt(III) complexes in the reaction medium. The rate constant of each complex increases with initial concentration of one of the reactants surfactant-cobalt(III) complex, which shows that self micelles formed by surfactant-cobalt(III) complex itself has much influence on these reactions. The electron transfer reaction of the surfactant-cobalt(III) complexes was also carried out in a medium of various concentrations of β-cyclodextrin. β-cyclodextrin retarded the rate of the reaction.     

Studies on outer-sphere electron transfer reactions of surfactant–cobalt(III) complexes with iron(II) in liposome (dipalmitoylphosphotidylcholine) vesicles

The effect of unilamellar vesicles of dipalmitoylphosphotidylcholine (DPPC), both below and above the phase transfer region, on the second-order rate constants for outer-sphere electron transfer between Fe²⁺ and the surfactant?Ccobalt(III) complexes, cis-[Co(en)₂(C₁₂H₂₅NH₂)₂]³⁺ and cis-[Co(trien)(C₁₂H₂₅NH₂)₂]³⁺ (en?=?ethylenediamine, trien?=?triethylenetetramine, C₁₂H₂₅NH₂?=?dodecylamine) was studied by UV?CVis absorption spectroscopy. Below the phase transition temperature of DPPC, the rate decreased with increasing concentration of DPPC, while above the phase transition temperature the rate increased with increasing concentration of DPPC. It is concluded that below the phase transition temperature, there is an accumulation of surfactant?Ccobalt(III) complexes at the interior of the vesicle membrane through hydrophobic effects, and above the phase transition temperature the surfactant?Ccobalt(III) complex is released from the interior to the exterior surface of the vesicle. Through isokinetic plots, we have established that the mechanism of the reaction does not alter during the phase transition of DPPC.     

Water‐soluble and Halogen‐free Hexaammine Complexes of Metal Ions of Group 9 – Synthesis,Crystal Structures,and Vibrational Spectra

Reaction of [M(NH₃)₆]Cl₃ (M = Co, Rh, Ir) and [Ir(NH₃)₅(OH₂)]Cl₃ with (NH₄)₂C₂O₄ · H₂O in aqueous solution resulted in the isolation of [M(NH₃)₆]₂(C₂O₄)₃ · 4 H₂O and [Ir(NH₃)₅(OH₂)]₂(C₂O₄)₃ · 4 H₂O, respectively. The complexes have been characterized by X‐ray crystallography, IR and UV/VIS spectroscopy. The isomorphous compounds crystallize in the orthorhombic space group Pnnm (No. 58). Four molecules of crystal water are involved in an extended three‐dimensional hydrogen bonding network. The librational modes of the lattice water around 600 cm^–1 allow the characterization of [Ir(NH₃)₆]₂(C₂O₄)₃ · 4 H₂O and [Ir(NH₃)₅(OH₂)]₂(C₂O₄)₃ · 4 H₂O, respectively, by IR spectroscopy. The band around 600 cm^–1 shows a significant frequency shift in the IR spectra of the hexaammine and aquapentaammine complex of iridium(III) and, by that, a distinction is possible.     

Microheterogeneous mediated electron transfer reaction (ETR) of surfactant cobalt(III) complexes by Fe2+: Effect of pyridine substituent as co ligand

The outer sphere electron transfer reaction of surfactant cobalt(III) complexes, Cis-[Co(en)₂(4CNP)(C₁₂H₂₅NH₂)](ClO₄)₃ 1, Cis-[Co(trien)(4CNP)(C₁₂H₂₅NH₂)](ClO₄)₃ 2 and Cis-[Co(trien)(4AMP)(C₁₂H₂₅NH₂)](ClO₄)₃ 3 (en: ethylenediamine, trien: triethylenetetramine, 4CNP: 4-cyanopyridine, 4AMP: 4-aminopyridine, C₁₂H₂₅NH₂: dodecylamine) have been investigated by Fe²⁺ ion in liposome vesicles (DPPC) and ionic liquids medium at different temperatures under pseudo first order conditions using an excess of the reductant. In the presence of ionic liquid medium the second order rate constant for this electron transfer reaction was found to increase with increasing concentration of ionic liquids. Below the phase transition temperature of DPPC, the rate decreased with increasing concentration of DPPC, while above the phase transition temperature the rate increased with increasing concentration of DPPC for the same complexes has also been studied. Experimentally the reactions were found to be second order and the electron transfer postulated as outer sphere. The results have been discussed in terms of increased hydrophobic effect, self aggregation and the presence of pyridine ligand containing 4-amino and 4-cyano substituent.     

Asymmetric salt effects on anion/cation reactions: A comparative study of the [Fe(CN)6]4− + [Co(NH3)5pz]3+ and [Ru(NH3)5pz]2+ + [Co(C2O4)3]3− reactions

The kinetics of electron transfer reactions between [Fe(CN)₆]^4? and [Co(NH₃)₅pz]³⁺ and between [Ru(NH₃)₅pz]²⁺ and [Co(C₂O₄)₃]^3? was studied in concentrated salt solutions (Na₂SO₄, LiNO₃, and Ca(NO₃)₂). An analysis of the experimental kinetic data, k_obs, permits us to obtain the true (unimolecular) electron transfer rate constants corresponding to the true electron transfer process (precursor complex → successor complex), k_et. The variations of both, k_obs and k_et, with salt concentrations are opposite for these reactions. These opposite tendencies can be rationalized by using the Marcus–Hush treatment for electron transfer reactions. The conclusion is that the negative salt effect found for the first reaction ([Fe(CN)₆]^4? + [Co(NH₃)₅pz]³⁺) is due to the increase of the reaction and reorganization free energies when the concentration of salt increases. In the case of the second reaction ([Ru(NH₃)₅pz]²⁺ + [Co(C₂O₄)₃]^3?), the positive salt effect observed is caused by the fact that the driving force becomes more favorable when the concentration of salt increases. Thus, it is shown that for anion/cation electron transfer reactions the kinetic salt effect depends on the charge sign of the oxidant (and the reductant). © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 37: 81–89, 2005     

Formation of lithium,sodium and potassium complexes with 1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol (taci)

Single crystals of (1,3‐diamino‐5‐azaniumyl‐1,3,5‐trideoxy‐cis‐inositol‐κ³O²,O⁴,O⁶)(1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol‐κ³O²,O⁴,O⁶)lithium(I) diiodide dihydrate, [Li(C₆H₁₆N₃O₃)(C₆H₁₅N₃O₃)]I₂·2H₂O or [Li(Htaci)(taci)]I₂·2H₂O (taci is 1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol), (I), bis(1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol‐κ³O²,O⁴,O⁶)sodium(I) iodide, [Na(C₆H₁₅N₃O₃)₂]I or [Na(taci)₂]I, (II), and bis(1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol‐κ³O²,O⁴,O⁶)potassium(I) iodide, [K(C₆H₁₅N₃O₃)₂]I or [K(taci)₂]I, (III), were grown by diffusion of MeOH into aqueous solutions of the complexes. The structures of the Na and K complexes are isotypic. In all three complexes, the taci ligands adopt a chair conformation with axial hydroxy groups, and the metal cations exhibit exclusive O‐atom coordination. The six O atoms of the resulting MO₆ unit define a centrosymmetric trigonal antiprism with approximate D_3d symmetry. The interligand O...O distances increase significantly in the order Li < Na < K. The structure of (I) exhibits a complex three‐dimensional network of R—NH₂—H...NH₂—R, R—O—H...NH₂—R and R—O—H...O(H)—H...NH₂—R hydrogen bonds. The structures of the Na and K complexes consist of a stack of layers, in which each taci ligand is bonded to three neighbours via pairwise O—H...NH₂ interactions between vicinal HO—CH—CH—NH₂ groups.     

Thermolyse von Cyanokomplexen. VII. Über die Thermischen Zersetzungsreaktionen der Hexacyanokobalte(III); Ligandenumlagerungen bei der Thermolyse

Thermolysis of cyano complexes. VII. On the thermal decomposition of hexacyanocobaltate(III); ligand exchange during thermolysis The thermal decomposition of hexacyanocobaltates(III) yields, as products of successive intramolecular redox reactions, first dicyan and Co^II(Co^III)-complexes, then Co^II[Co^II]-complexes and simple Co^II(CN)₂, respectively, and finally Co^ICN and elemental Co, respectively. All the compounds of the [Co^III(NH₃)₆]³⁺ cation with the cyanometallate anions of Co, Fe, Cr, Mn, Ni, Mo yield the same DTA curve as [Co(NH₃)₆][Co(CN)₆] does; in the case of Ni and Cr, which are capable of forming ammine complexes, simultaneous mutual ligand exchange occurs.     

Tellurium‐Halogen Secondary Bonding in the Crystal Structures of [Q]+[PhTeCl4]— (Q = C5NH6, 2‐Br‐C5NH5, {2‐Br‐C5NH5}{Co(NH3)4Cl2})

The reaction of diphenylditelluride with pyridine, 2‐bromopyridine or 2‐bromopyridine/tetraamminedichlorocobalt(III) chloride in 12 M hydrochloric acid afforded the tetrachlorophenyltellurate(IV) compounds [C₅NH₆][PhTeCl₄] ( 1 ), [2‐Br‐C₅NH₅] [PhTeCl₄] ( 2 ), and [{2‐Br‐C₅NH₅}{Co(NH₃)₄Cl₂}] [PhTeCl₄]₂ ( 3 ). They were all characterized structurally by single crystal X‐ray diffraction. In all structures, the arrangement about the tellurium atoms is square pyramidal. The [PhTeCl₄]^— anions in 1 and 2 form trimeric and dimeric units, respectively, through Te···Cl secondary bonding. Compound 3 shows an unusual face‐to‐face packing of the [PhTeCl₄]^—anions with hydrogen bonding to the bromopyridium cation.     

Second‐sphere coordination in anion binding: sodium hexa­ammine­cobalt(III) tetra­kis­(4‐fluoro­benzoate) monohydrate

In sodium hexa­amminecobalt(III) tetra­kis­(4‐fluoro­benzoate) monohydrate, Na[Co(NH₃)₆](C₇H₄FO₂)₄·H₂O, determined at 180 K, [Co(NH₃)₆]³⁺ cations lie on centres of inversion and form layers in which their C₄ axes lie perpendicular to the layer planes. 4‐Fluoro­benzoate anions lie on twofold axes and general positions and adopt near‐planar geometries. Na⁺ cations and water mol­ecules lie on twofold axes, forming [NaO₅] square pyramids that lie between the [Co(NH₃)₆]³⁺ cations. The second‐sphere inter­actions between [Co(NH₃)₆]³⁺ cations and 4‐fluorobenzoate anions comprise edge‐to‐face and vertex‐to‐face arrangements. The structure is closely comparable with that of the benzoic acid salt, demonstrating that fluorination of the anion in the para position has no significant influence on the second‐sphere inter­actions and minimal influence on the gross crystal structure.     

Synthesis, X-ray structure, and spectroscopic investigation of new Co(II)/Cd(II) complexes formed via the reaction of 1-hydroxymethyl-3,5-dimethylpyrazole and Co0, CdCl2, NH4I

The novel complex [Co(L)Cl]₂[CdI₄] obtained in situ from the redox system (Co⁰, CdCl₂, NH₄I, 1-hydroxymethyl-3,5-dimethylpyrazole) was characterized by X-ray diffraction IR, UV–VIS as well as magnetic and thermal investigations. The ligand, tris(1-(3,5-dimethylpyrazolylmethyl)amine (L) was synthesized in situ as a product of condensation 1-hydroxymethyl-3,5-dimethylpyrazole and ammonia molecule formed during redox process. The crystal structure of 1 includes in the unit cell two chemically identical but symmetry-independent cations: [Co(1)(L)Cl]⁺ and [Co(2)(L)Cl]⁺. Each of the [Co(L)Cl]⁺ complex ions has C₃ point group symmetry, but the point group symmetry of the trigonal bipyramidal coordination spheres of [CoN₃N′Cl] and tetrahedral sphere of [CdI₄] has C_3v point group symmetry.     

Linkage isomeric oxamate chelates: rac‐bis(ethane‐1,2‐diamine)oxamatocobalt(III) bis(trifluoromethanesulfonate) dihydrate and Λ(+)578‐bis(ethane‐1,2‐diamine)[oxamato(2−)]cobalt(III) trifluoromethanesulfonate

The structures of rac‐bis(ethane‐1,2‐diamine)(oxamato‐κ²O¹,O²)cobalt(III) bis(trifluoromethanesulfonate) dihydrate, [Co(C₂H₂NO₃)(C₂H₈N₂)₂](CF₃SO₃)₂·2H₂O, (I), and Λ(+)₅₇₈‐bis(ethane‐1,2‐diamine)[oxamato(2−)‐κ²N,O¹]cobalt(III) trifluoromethanesulfonate, [Co(C₂HNO₃)(C₂H₈N₂)₂]CF₃SO₃, (II), are compared. Together, the two complexes constitute the first pair of linkage isomers of bidentate oxamate available for structural comparison.     

Coexistence of Two Thermally Induced Intramolecular Electron Transfer Processes in a Series of Metal Complexes [M(Cat‐N‐BQ)(Cat‐N‐SQ)]/[M(Cat‐N‐BQ)2] (M=Co,Fe, and Ni) bearing Non‐Innocent Catechol‐Based Ligands: A Combined Experimental and Theoretical Study

The different thermally induced intermolecular electron transfer (IET) processes that can take place in the series of complexes [M(Cat‐N‐BQ)(Cat‐N‐SQ)]/[M(Cat‐N‐BQ)₂], for which M=Co ( 2 ), Fe ( 3 ) and Ni( 4 ), and Cat‐N‐BQ and Cat‐N‐SQ denote the mononegative (Cat‐N‐BQ^?) or dinegative (Cat‐N‐SQ^2?) radical forms of the tridentate Schiff‐base ligand 3,5‐di‐tert‐butyl‐1,2‐quinone‐1‐(2‐hydroxy‐3,5‐di‐tert‐butylphenyl)imine, have been studied by variable‐temperature UV/Vis and NMR spectroscopies. Depending on the metal ion, rather different behaviors are observed. Complex 2 has been found to be one of the few examples so far reported to exhibit the coexistence of two thermally induced electron transfer processes, ligand‐to‐metal (IET^LM) and ligand‐to‐ligand (IET^LL). IET^LL was only found to take place in complex 3 , and no IET was observed for complex 4 . Such experimental studies have been combined with ab initio wavefunction‐based CASSCF/CASPT2 calculations. Such a strategy allows one to solicit selectively the speculated orbitals and to access the ground states and excited‐spin states, as well as charge‐transfer states giving additional information on the different IET processes.     

Zur Kenntnis der Sulfito-kobalt(III)-Ammine. III. Hydrogensulfitokobalt(III)-Ammine

Sulphito Cobalt(III) Ammines. III. Hydrogensulphito Cobalt(III) Ammines Concentrated acids react with [CoSO₃(NH₃)₅]⁺ salts hydrogen- sulphitopentaamminecobalt(III) complexes. [Co(HSO₃)(NH₃)₅]Cl₂, [Co(HSO₃)(NH₃)₅]Br₂ and [Co(HSO₃)(NH₃)₅](HSO₄)₂·H₂O have been isolated. These substances are yellow coloured in contrast to an earlier work which reported red colour. Furthermore, the hydrogensulphitoacidotetreaammine complexes [Co(HSO₃)Cl(NH₃)₄]Cl, [Co(HSO₃)Cl(NH₃)₄]ClO₄·H₂O, [Co(HSO₃)Br(NH₃)₄]Br and [Co(HSO₃) CN(NH₃)₄]Cl habe been prepared. [Co(HSO₃)Br(NH₃)₄]Br is losing spontaneously HBr forming [CoSO₃Br(NH₃)₄]. The neutral complex [Co(HSO₃)SO₃(NH₃)₄]·1/2H₂O has been obtained from cis- NH₄[Co(SO₃)₂(NH₃)₄] and HCl. The absorption spectra in the IR, visible and UV region are reported and discussed. The HSO₃ group is coordinated to Co through the S atom. The Co? S bond is weaker than in the sulphito complexes as concluded from the RAMAN spectrum. In the new complexes, the hydrogensulphito ligand causes a minor trans effect than the sulphito ligand.     

Gold(I) and Silver(I) Complexes of Diphosphacyclobutadiene Cobaltate Sandwich Anions

The synthesis and structural characterization of the first coordination compounds of bis(diphosphacyclobutadiene) cobaltate anions [M(P₂C₂R₂)₂]^? is described. Reactions of the new potassium salts [K(thf)₃{Co(η⁴‐P₂C₂tPent₂)₂}] ( 1 ) and [K(thf)₄{Co(η⁴‐P₂C₂Ad₂)₂}] ( 2 ) with [AuCl(tht)] (tht=tetrahydrothiophene), [AuCl(PPh₃)] and Ag[SbF₆] afforded the complexes [Au{Co(P₂C₂tPent₂)₂}(PMe₃)₂] ( 3 ), [Au{Co(P₂C₂Ad₂)₂}]_x ( 4 ), [Ag{Co(P₂C₂Ad₂)₂}]_x ( 5 ), [Au(PMe₃)₄][Au{Co(P₂C₂Ad₂)₂}₂] ( 6 ), [K([18]crown‐6)(thf)₂][Au{Co(P₂C₂Ad₂)₂}₂] ( 7 ), and [K([18]crown‐6)(thf)₂][M{Co(P₂C₂Ad₂)₂}₂] ( 8 : M=Au 9 : M=Ag) in moderate yields. The molecular structures of 2 and 3 , and 6 – 9 were elucidated by X‐ray crystallography. Complexes 4 – 9 were thoroughly characterized by ³¹P and ¹³C solid state NMR spectroscopy. The complexes [Au{Co(P₂C₂Ad₂)₂}]_x ( 4 ) and [Ag{Co(P₂C₂Ad₂)₂}]_x ( 5 ) exist as coordination polymers in the solid state. The linking mode between the monomeric units in the polymers is deduced. The soluble complexes 1 – 3 , 6 , and 7 were studied by multinuclear ¹H‐, ³¹P{¹H}‐, and ¹³C{¹H} NMR spectroscopy in solution. Variable temperature NMR measurements of 3 and 6 in deuterated THF reveal the formation of equilibria between the ionic species [Au(PMe₃)₄]⁺, [Au(PMe₃)₂]⁺, [Co(P₂C₂R₂)₂]^?, and [Au{Co(P₂C₂R₂)₂}₂]^? (R=tPent and Ad).     

First Characterization of an Extended Ammonium‐Ammonia Complex [{NH4(NH3)4}+(μ‐NH3)2] in the Crystal Structure of [NH4(NH3)4][Co(C2B9H11)2] · 2 NH3

The compound [NH₄(NH₃)₄][Co(C₂B₉H₁₁)₂] · 2 NH₃ ( 1 ) was prepared by the reaction of Na[Co(C₂B₉H₁₁)₂] with a proton‐charged ion‐exchange resin in liquid ammonia. The ammoniate 1 was characterized by low temperature single‐crystal X‐ray structure analysis. The anionic part of the structure consists of [Co(C₂B₉H₁₁)₂]^‐ complexes, which are connected via C‐H···H‐B dihydrogen bonds. Furthermore, 1 contains an infinite equation/tex2gif-stack-2.gif[{NH₄(NH₃)₄}⁺(μ‐NH₃)₂] cationic chain, which is formed by [NH₄(NH₃)₄]⁺ ions linked by two ammonia molecules. The N‐H···N hydrogen bonds range from 1.92 to 2.71Å (DHA = Donor···Acceptor angles: 136‐176°). Additional N‐H···H‐B dihydrogen bonds are observed (H···H: 2.3‐2.4Å).     

Coordination Chemistry of Acrylamide 4. Crystal Structures and IR Spectroscopic Properties of Acrylamide Complexes with CoII,NiII, and ZnII nitrates

Acrylamide complexes of metal nitrates: [M(O‐OC(NH₂)CHCH₂)_n(H₂O)_m][NO₃]₂ (M = Co( 1 ), Ni( 2 ) (n = 6 and m = 0) and Zn( 3 ) (n = 4 and m = 2)) have been determined by using single crystal X‐ray diffraction analysis. All complexes crystallize in the triclinic space group . The structures of 1 and 2 represent octahedral species [M(AAm)₆]²⁺ (AAm = O‐OC(NH₂)CHCH₂ and M = Co or Ni) and uncoordinated nitrate ions. The structure of 3 involves the octahedral cation [Zn(AAm)₄(H₂O)₂]²⁺ in which the Zn²⁺ environment includes oxygen atoms of four acrylamide and two water molecules that are stabilized using ionic nitrate ions. The observations of the solid‐state IR spectroscopic vibrational frequencies of these acrylamide complexes are in agreement with the crystal structures.     

Studies on outer sphere electron transfer reactions of some surfactant-cobalt(III) complexes with ferrocyanide anion

The kinetics and mechanism of reduction of the surfactant-cobalt(III) complex ions, cis-[Co(bpy)₂(C₁₂H₂₅NH₂)₂]³⁺ and cis-[Co(phen)₂(C₁₂H₂₅NH₂)₂]³⁺ (bpy = bipyridyl, phen = 1,10-phenan-throline, C₁₂H₂₅NH₂ = dodecylamine) by Fe(CN₆)⁴⁻ in self-micelles were studied at different temperatures. Experimentally the reaction was found to be second order and the electron transfer postulated as outersphere. The rate constant for the electron transfer reaction for both the complexes was found to increase with increase in the initial concentration of the surfactant-cobalt(III) complex. This peculiar behaviour of dependence of second-order rate constant on the initial concentration of one of the reactants has been attributed to the presence of various concentration of micelles under different initial concentration of the surfactantcobalt(III) complexes in the reaction medium. The effect of inclusion of the long aliphatic chain of the surfactant complex ions into β-cyclodextrin on these reactions has also been studied.