Influence of ligands on the fac⇌Δhνmer isomerization in [RuCl3(NO)(P–P)] complexes, [P–P = R2P(CH2)nPR2 (n = 1–3) and R2P(CH2)POR2, PR2–CHCH–PR2, R = Ph and (C6H11)2P-(CH2)2-P(C6H11)2]

[RuCl₃(NO)(P–P)], [P–P = R₂P(CH₂)_nPR₂ (n = 1–3) and R₂P(CH₂)POR₂, PR₂–CHCH–PR₂, R = Ph and (C₆H₁₁)₂P-(CH₂)₂-P(C₆H₁₁)₂] were obtained and characterized by ³¹P {¹H} NMR, IR spectroscopies and cyclic voltammetry. The structures of fac-[RuCl₃(NO)(P–P)], P–P = dppm (1), dppe (2), c-dppen (3) and dppp (4), mer-[RuCl₃(NO)(dcpe)] (6a) and mer-[RuCl₃(NO)(dppmO)] (7) have been determined by X-ray diffraction. Photochemical isomerization of fac- to mer-[RuCl₃(NO)(P–P)] was observed under white light in a CH₂Cl₂ solution and in solid state. The isomerization processes were followed by IR and ³¹P {¹H} spectra. The mer-[RuCl₃(¹⁵NO)(dppb)] isomer was used for the definition of the phosphorus atoms in the structure of the complex in solution. The electrochemical study shows that the oxidation/reduction processes observed in these complexes are dependent on both the isomer (fac or mer) and the solvent. In CH₂Cl₂, the NO⁺ reduction potentials are less negative for the mer-isomers than for the fac ones, while in CH₃CN solvent these potentials are, in general, very close for both isomers.     

Preparation, characterization and redox chemistry of oxo-centered triruthenium dimers linked by bis(diphenylphosphino)anthracene and -ferrocene

Diphosphine-bridged dimers of oxo-centered triruthenium-acetate cluster units, i.e., [{Ru₃O(OAc)₆(py)₂}₂(dppan)](PF₆)₂ (2) and [{Ru₃O(OAc)₆(py)₂}₂(dppf)](PF₆)₂ (3) were prepared by reaction of 2.3 equivalent [Ru₃O(OAc)₆(py)₂(CH₃OH)](PF₆) with 9,10-bis(diphenylphosphino)anthracene (dppan) or 1,1′-bis(diphenylphosphino)ferrocene (dppf), respectively. Apparent redox wave splitting is observed in complex 2, revealing the presence of electronic communication between two triruthenium units mediated through bridging dppan. The complexes were characterized by elemental analysis, IR, UV-Vis, ³¹P NMR, and ES-MS spectroscopies, and cyclic and differential-pulse voltammetry. The crystal structure of complex 3 was determined by X-ray crystallography.     

Synthesis and structural characterization of zwitterionic oxorhenium(V) complexes with 2-hydroxypyridine

[ReOX₃(PPh₃)₂] complexes (X = Cl and Br) react with equivalent amounts of 2-hydroxypyridine (Hhp) under formation of the mono-substituted, zwitterionic complexes mer-[ReOCl₃(Hhp)(PPh₃)] (1) and mer-[ReOBr₃(Hhp)(PPh₃)] (2). Crystal structure determinations of 1 · CH₂Cl₂ and 2 revealed the Cl and Br ligands adopt a mer arrangement. The Hhp ligands coordinate neutral and monodentate via their exocyclic oxygen atoms in axial positions, trans to the oxo groups. The distorted octahedral coordination sphere of the rhenium(V) complexes is completed by the phosphorus atom of the remaining PPh₃ ligand.     

X-ray structures of dinuclear copper(I) and polynuclear copper(II) complexes with the 2,4-bis(cyanamido)cyclobutane-1,3-dione dianion

From the 2,4-bis(cyanamido)cyclobutane-1,3-dione dianion (2,4-NCNsq²⁻), two copper complexes [Cu₂(PPh₃)₄(PhCN)₂(μ-2,4-NCNsq)] · PhCN (1) and [Cu(dien)(μ-2,4-NCNsq) · H₂O]_n (2) have been synthesized and characterized by IR and electronic absorption spectroscopies. Their structures have been determined by X-ray crystallography. Complex 1 is a dinuclear copper(I) compound with a 2,4-NCNsq²⁻ ligand bridging two copper atoms through the nitrile nitrogen atoms. Complex 2 appears as a 3D network constituted of copper(II) atoms bridged by 2,4-NCNsq²⁻ dianions. This complex presents an unexpected coordination mode of the bis(cyanamido) ligands which are both coordinated via the nitrile functions and via the amido nitrogen atoms of the NCN groups.     

Rational enhancement of the coordination capability of Ru(III)(salen)-nitronyl nitroxide building block: A step towards 2p–3d–4d magnetic edifices

The reaction of [Ru(salen)(PPh₃)Cl] and the 5-imidazol-substituted nitronyl nitroxide radical (NIT-(5)ImH) yields the [Ru(salen)(PPh₃)(NIT-(5)ImH)](ClO₄) (1) complex which has been characterized by single crystal X-ray diffraction. This analysis reveals that the Ru(III) ion is coordinated to a tetradentate salen^2? ligand in equatorial positions while one PPh₃ ligand and one NIT-(5)ImH radical are coordinated in axial positions. This led to Ru^III ions in tetragonally elongated octahedral geometry. From the magnetic point of view ferromagnetic intramolecular interaction (J₁ = +2.47 cm^?1) have been found between the Ru(III) ion and the coordinated NIT-(5)ImH while no significant intermolecular antiferromagnetic interactions are observed at low temperature leading to a ground spin state S = 1. The absence of intermolecular magnetic interaction is explained by considering the crystal packing of (1) where the [Ru(salen)(PPh₃)(NIT-(5)ImH)]⁺ moieties are relatively well isolated. This has to be compared with the situation observed in the previously reported [Ru(salen)(PPh₃)-(NIT)]⁺ compound (2) where ferromagnetic Ru^III–NIT interaction were identified and the crystal packing generate intermolecular antiferromagnetic interactions that complicated the study. The analysis of this compound confirms the rather isotropic g values that were found of (2) and of [Ru(salen)(PPh₃)(N₃)], (3) a radical-free analogue. Moreover it is also a step towards extended structures based on Ru^III–NIT moieties since this compound possesses a free bischelating site likely to coordinate additional metallic ions.     

Comparing anti-HIV,antibacterial, antifungal,micellar, and cytotoxic properties of tricarboxylato dendritic amphiphiles

Three series of homologous dendritic amphiphiles—RCONHC(CH₂CH₂COOH)₃, 1(n); ROCONHC(CH₂CH₂COOH)₃, 2(n); RNHCONHC(CH₂CH₂COOH)₃, 3(n), where R = n-C_nH_2n+1 and n = 13–22 carbon atoms—were assayed for their potential to serve as antimicrobial components in a topical vaginal formulation. Comparing epithelial cytotoxicities to the ability of these homologues to inhibit HIV, Neisseria gonorrhoeae, and Candida albicans provided a measure of their prophylactic/therapeutic potential. Measurements of the ability to inhibit Lactobacillus plantarum, a beneficial bacterium in the vagina, and critical micelle concentrations (CMCs), an indicator of the potential detergency of these amphiphiles, provided additional assessments of safety. Several amphiphiles from each homologous series had modest anti-HIV activity (EC₅₀ = 110–130 μM). Amphiphile 2(18) had the best anti-Neisseria activity (MIC = 65 μM), while 1(19) and 1(21) had MICs against C. albicans of 16 and 7.7 μM, respectively. Two measures of safety showed promise as all compounds had relatively low cytotoxic activity (EC₅₀ = 210–940 μM) against epithelial cells and low activity against L. plantarum, 1(n), 2(n), and 3(n) had MICs ? 490, 1300, and 940 μM, respectively. CMCs measured in aqueous triethanolamine and in aqueous potassium hydroxide showed linear dependences on chain length. As expected, the longest chain in each series had the lowest CMC—in triethanolamine: 1(21), 1500 μM; 2(22), 320 μM; 3(22), 340 μM, and in potassium hydroxide: 1(21), 130 μM; 3(22), 40 μM. The CMC in triethanolamine adjusted to pH 7.4 was 400 μM for 1(21) and 3900 μM for 3(16). The promising antifungal activity, low activity against L. plantarum, relatively high CMCs, and modest epithelial cytotoxicity in addition to their anti-Neisseria properties warrant further design studies with dendritic amphiphiles to improve their safety indices to produce suitable candidates for antimicrobial vaginal products.     

Syntheses and crystal structures of di- and trimethyltin (IV) derivatives with phenylphosphonic acid

Three types of methyltin phosphonates, {[(CH₃)₃Sn]₄(O₃PPh)₂}_n (1), {[(CH₃)₃Sn]₂(O₃PPh) · CH₃OH}_n (2) and {[(CH₃)₂SnO₃PPh]₄}_n (3) were synthesized by the reaction of phenylphonic acid with trimethyltin (IV) chloride and dimethyltin (IV) dichloride, respectively. Complexes 1, 2 and 3 were characterized by elemental analysis, IR, NMR (¹H, ¹³C, ³¹P and ¹¹⁹Sn) spectroscopy, TGA and X-ray crystallography diffraction analysis. The X-ray analysis of complex 1 shows that the structure is a polymeric infinite 1D zigzag chain. In complex 2, the oxygen atom of methanol molecule is coordinated to the tin atoms, and a 2D network is generated via O–H?O hydrogen bonds. In complex 3, a novel 2D network containing 12-membered (Sn₃O₆P₃) rings is formed.     

Metal-assisted preparation of the alkenyl ketone and carbonyl complexes from 1-alkyne and H2O: C–C triple bond cleavage of terminal alkyne

Reactions of Cp*RhCl₂(PPh₃) (1) with 1-alkyne and H₂O in the presence of KPF₆ generated alkenyl ketone complexes [Cp*Rh(CRCHCOCH₂R)(PPh₃)](PF₆) (2) (R = Ph (a), C₆H₄−p-Me (b), C₆H₄-p-COOMe (c), C₆H₄-p-NO₂ (d)). A similar complex [Cp*Rh(CPhCHCOCH₂Ph)(PMePh₂)](PF₆) (2e) was obtained by use of Cp*RhCl₂(PMePh₂). It was revealed by X-ray analyses of 2b, 2c and 2e that the complexes 2 consist of the five-membered ring structures bound by the carbon and oxygen atoms of the alkenyl ketone group. Similar reactions of Cp*IrCl₂(PPh₃) (6) or (C₆Me₆)RuCl₂(PPh₃) (7) proceeded with a cleavage of C–C triple bond of 1-alkyne without formation of an alkenyl ketone complex, affording the corresponding carbonyl complexes, [Cp*IrCl(PPh₃)(CO)](PF₆) (8) or [(C₆Me₆)RuCl(PPh₃)(CO)](PF₆) (9). The diphosphine complexes [(Cp*MCl₂)₂{μ-diphos}] (4: M = Rh, diphos = dppm,; 12a: M = Ir, diphos = dppm; 12b: M = Ir, diphos = dppb) gave a Cl-bridged rhodium complex [{Cp*Rh(μ-Cl)}₂{μ-dppm}](PF₆)₂ (5), mono-carbonyl or dicarbonyl iridium complexes,[(Cp*IrCl₂){μ-dppm}{Cp*IrCl(CO)}](PF₆)(13a) or [{Cp*IrCl(CO)}₂{μ-dppb}](PF₆)₂ (14b), respectively.     

Diphosphine substitution in pentakis(arylisocyanide)cobalt(I) complexes; 31P NMR,cyclic voltammetric and ESI mass spectrometry studies

Five new complexes of the type [Co(CNC₆H₃iPr₂-2,6)₄PPh₂-R′-PPh₂]X, X = BF₄, ClO₄; R′ =–(CH₂)₂– (1), –(CH₂)₃– (2), –CHCH-trans (3), –CC– (4) and –C₆H₄-p (5); and two new bimetallic complexes, [{Co(CNC₆H₃iPr₂-2,6)₄}₂(μ-PPh₂(CH₂)₃PPh₂)](ClO₄)₂ (6) and [{Co(CNC₆H₃iPr₂-2,6)₄}₂(μ-PPh₂C₆H₄PPh₂-p)](ClO₄)₂ (7), have been synthesized and characterized by various spectroscopic methods.Known monometallic and bimetallic complexes bearing the ligand CNC₆H₃Et₂-2,6 instead of CNC₆H₃iPr₂-2,6 have been included in the ³¹P NMR, cyclic voltammetric and mass spectrometry studies.Comparison of the CNC₆H₃iPr₂-2,6 with the CNC₆H₃Et₂-2,6 complexes shows that the increased steric bulkiness of the former makes it more suitable for synthesis of the monometallic complexes, whilst the CNC₆H₃Et₂-2,6 is more apt to give bimetallic complexes.Thus, the two arylisocyanides are complementary with respect to synthesis of the monometallic and bimetallic complexes.The ³¹P NMR indicates that the diphosphines in monometallic complexes behave as non-fluxional, monodentate ligands at ambient temperature, with ³¹P–³¹P coupling shown for the PPh₂CH₂PPh₂, PPh₂(CH₂)₂PPh₂ and PPh₂CCPPh₂ ligands. Cyclic voltammetry fails to show electronic communication in the bimetallic complexes, and mass spectrometry indicates significantly greater stability for fragments containing potentially chelating diphosphines as compared to diphosphines that cannot chelate.     

Structure and catalytic activity of rhodium(I) carbene complexes in polymerization of phenylacetylene

Rh(I) carbene complexes of [RhX(bmim)(η⁴-1,5-cod)] type (bmim = 1-butyl-3-methyl imidazolium cation, X = Cl 2, Br 3, I 4), obtained in the reaction of [Rh(OMe)(η⁴-1,5-cod)]₂ (1) with [bmim]X ionic liquids, catalyzed polymerization of phenylacetylene (PA) to cis-polyphenylacetylene (PPA) in CH₂Cl₂ and in ionic liquids. The yield of PPA increased and molecular weight (M_w) decreased after addition of phosphorus ligands PPh₃ or P(OPh)₃. Complex 4 reacted with P(OPh)₃ giving cis-[RhI(bmim)(P(OPh)₃)₂] (5) complex which catalyzed oligomerization but not polymerization of PA.     

Acetato complexes of molybdenum(V): A novel tetranuclear core based on the metal–metal bonded {Mo2O4}2+ units

A series of acetato complexes of molybdenum(V), based on the singly metal–metal bonded {Mo₂O₄}²⁺ structural fragment, has been prepared. A dinuclear (PyH)₃[Mo₂O₄Cl₄(OOCCH₃)] · CH₃CN (1) (PyH⁺ = pyridinium cation, C₅H₅NH⁺) was obtained upon the reaction of (PyH)₅[MoOCl₄(H₂O)]₃Cl₂ with the equimolar solution of pyridine and acetic acid in acetonitrile at ambient conditions. The acetato ligand in 1 is coordinated to a pair of molybdenum atoms in a syn–syn bidentate bridging manner. (PyH)_n[MoOBr₄]_n afforded in an analogous synthetic procedure a tetranuclear cluster, [Mo₄O₈(OOCCH₃)₃(OH)Py₄] · 1/2CH ₃CN · 1/2H₂O (3), with a novel core which may be envisioned as the acetate- and hydroxide-assisted assembly of {Mo₂O₄}²⁺ building blocks. Its structure is presented in terms of known tetranuclear clusters which are also composed of two {Mo₂O₄}²⁺ units. The acetato ligands in 3 adopted apart from bidentate bridging binding modes also a monodentate one. Partial substitution of chlorido ligands in (PyH)₃[Mo₂O₄Cl₄(OOCCH₃)] · CH₃CN (1) with pyridine resulted in a neutral [Mo₂O₄Cl(OOCCH₃)Py₃] · PrⁱOH · Py (2) which retained the original acetate coordination. The title compounds were fully characterized by X-ray diffraction studies and infrared vibrational spectroscopy.     

Two new N-heterocyclic carbene silver(I) complexes with the π–π stacking interactions

The precursors bis[N-(alkyl)benzimidazoliumylmethyl]durene halide (1a: alkyl = C₂H₅, halide = Br^?; 1b: alkyl = n-C₄H₉, halide = Cl^?; durene = 1,2,4,5-tetramethylbenzene) and their two new NHC silver(I) complexes [Durene(CH₂BimyEtAgBr)₂] (2a) and [Durene(CH₂BimyⁿBuAgCl)₂] (2b) (Bimy = benzimidazol-2-ylidene) have been prepared and characterized. In the crystal structures of 2a and 2b the aromatic π–π stacking interactions are observed.     

Syntheses,structures and properties of Zn(II) and Co(II) complexes of N-benzesulfonyl-l-glutamic acid ligand

The reaction of N-benzesulfonyl-l-glutamic acid (Bs-glu) with Zn(CH₃COO)₂ · 2H₂O or Co(CH₃COO)₂ · 4H₂O in the presence of imidazole (Im) produced two novel complexes [Zn(Im)₂(Bs-glu)]_n (1) and [Co(Im)₂(Bs-glu)]_n (2). Both of the complexes exhibit similar one-dimensional structural motif and coordination environment. Bs-glu adopts the bis-monodentated coordination mode linking two adjacent metal ions. The complex 1 shows intense photoluminescence in the solid state. Magnetic measurements for 2 show that the exchange interaction of the two Co(II) ions is antiferromagnetic.     

Synthesis,structures and urease inhibitory activity of cobalt(III) complexes with Schiff bases

A series of new cobalt(III) complexes were prepared. They are [CoL¹(py)₃]·NO₃ (1), [CoL²(bipy)(N₃)]·CH₃OH (2), [CoL³(HL³)(N₃)]·NO₃ (3), and [CoL⁴(MeOH)(N₃)] (4), where L¹, L², L³ and L⁴ are the deprotonated form of N′-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide, N′-(2-hydroxybenzylidene)-3-hydroxylbenzohydrazide, 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol, and N,N′-bis(5-methylsalicylidene)-o-phenylenediamine, respectively, py is pyridine, and bipy is 2,2′-bipyridine. The complexes were characterized by infrared and UV–Vis spectra, and single crystal X-ray diffraction. The Co atoms in the complexes are in octahedral coordination. Complexes 1 and 4 show effective urease inhibitory activities, with IC₅₀ values of 4.27 and 0.35 μmol L⁻¹, respectively. Complex 2 has medium activity against urease, with IC₅₀ value of 68.7 μmol L⁻¹. While complex 3 has no activity against urease. Molecular docking study of the complexes with Helicobacter pylori urease was performed.     

Structure and magnetic properties of LnIII[Ru2(CO3)4] · 8H2O

Ln^III[Ru₂(CO₃)₄] · 8H₂O (Ln = Gd, Nd, Ho, Yb) is formed from the reaction of Ln^III and [Ru₂(CO₃)₄]^3? in water. These Ln^III materials have a 3D network structure composed of linked chains and μ_n-CO₃ linkages to both Ru and Ln^III sites, and are best described as Ln^III(OH₂)₄[Ru₂(CO₃)₄]_1/2[Ru₂(CO₃)₄(OH₂)₂]_1/2 · 3H₂O. Complete characterization of the Gd^III species is presented, as the other Ln^III are isostructural and exhibit large spin–orbit coupling leading to complex magnetic behavior. Magnetic ordering is not observed above 2 K.     

Magnetostructural correlations and catecholase-like activities of μ-alkoxo-μ-carboxylato double bridged dinuclear and tetranuclear copper(II) complexes

Two μ-alkoxo-μ-carboxylato bridged dinuclear copper(II) complexes, [Cu₂(L¹)(μ-HCO₂)] (1) ((H₃L¹ = 1,3-bis(5-bromosalicylideneamino)-2-propanol)), [Cu₂(L²)(μ-HCO₂)] · dmf (2) (H₃L² = 1,3-bis(3,5-chlorosalicylideneamino-2-propanol)), and two μ-alkoxo-μ-dicarboxylato doubly bridged tetranuclear copper(II) complexes, [{Cu₂(L³)}₂(μ-O₂C–C(CH₃)₂–CO₂)] · 5H₂O · 3CH₃OH (3) ((H₃L³ = 1,3-bis(salicylid-deneamino)-2-propanol)) and [{Cu₂(L³)}₂(μ- O₂CCH₂–C₆H₄–CH₂CO₂)] · 2H₂O (4) have been prepared and characterized. The single crystal X-ray analysis shows that the structures of complexes 1 and 2 are dimeric with two adjacent copper(II) atoms bridged by μ-alkoxo-μ-carboxylato ligands with the Cu⋯Cu distances and Cu–O(alkoxo)–Cu angles are 3.511 Å and 132.85° for 1, 3.517 Å and 131.7° for 2, respectively. Complexes 3 and 4 consist of μ-alkoxo-μ-dicarboxylato doubly bridged tetranuclear Cu(II) complexes with mean Cu–Cu distances and Cu–O–Cu angles of 3.158 Å and 108.05° for 3 and 3.081 Å and 104.76° for 4, respectively. Magnetic measurements reveal that 1 and 2 are strong antiferromagnetically coupled with 2J = −156 and −152 cm⁻¹, respectively, while 3 and 4 exhibit ferromagnetic coupling with 2J = 86 and 155.2 cm⁻¹, respectively. The 2J values of 1–4 are linearly correlated to the Cu–O–Cu angles. Dependence of the pH at 25 °C on the reaction rate of oxidation of 3,4-di-tert-butylcatechol (3,5-dtbc) to the corresponding quinone catalyzed by 1–4 was studied. Complexes 1–4 exhibit high catecholase-like activity at pH 9.0 and 25 °C for oxidation of 3,5-di-tert-butylcatechol.     

Synthesis,antiproliferative and mitochondrial impairment activities of bis-alkyl-amino transplatinum complexes

A convenient synthetic route and the characterization of complexes trans-[PtCl₂(L)(PPh₃)] (L = Et₂NH (2), (PhCH₂)₂NH (3), (HOCH₂CH₂)₂NH) (4) are reported. The antiproliferative activity was evaluated on three human tumor cell lines. The investigation on the mechanism of action highlighted for the most active complex 4 the capacity to affect mitochondrial functions. In particular, both the induction of the mitochondrial permeability transition phenomenon and an aspecific membrane damage occurred, depending on concentration.     

Ketone H2-hydrogenation catalysts: Ruthenium complexes with the headphone-like ligand bis(phosphaadamantyl)propane

Treatment of 1,3-diphosphinopropane with acetylacetone in the presence of HCl gives the new chiral bis(phosphaadamantyl)propane ligand (bpap) (1) as a mixture of diastereoisomers. Recrystallization from ethanol gives a mixture enriched in rac diastereoisomer (90% rac/10% meso). The enriched mixture reacts with [RuHCl(PPh₃)₃] in refluxing THF to give [RuHCl(bpap)(PPh₃)] (2) in 73% yield. Compound 2 reacts readily with chiral diamines giving octahedral trans-[RuHCl(bpap)(diamine)] complexes 3 (diamine = (1R,2R)-1,2-diaminocyclohexane) and 4 (diamine = (1R,2R)-1,2-diphenylethylenediamine). Compounds 3 and 4 are very active catalysts for H₂-hydrogenation of neat acetophenone in the presence of KO^tBu as a strong base under mild conditions (room temperature, 3 atm of H₂). The low ee values for 1-phenethanol can be attributed to the similar shapes of two terminal adamantoid cages and the flexible backbone of the bpap ligand. The structures of complexes 2 and 3 have been determined by single-crystal X-ray diffraction.     

Syntheses,structures, and magnetic properties of heterobimetallic complexes based on tetracyanometallic building blocks

Two tetracyanometalate building blocks, [Fe(5,5′-dmbipy)(CN)₄]^? (2) and [Fe(4,4′-dmbipy)(CN)₄]^? (3) (5,5′-dmbipy = 5,5′-dimethyl-2,2′-bipyridine; 4,4′-dmbipy = 4,4′-dimethyl-2,2′-bipyridine), and two cyano-bridged heterobimetallic complexes, [Cu₂(bpca)₂(H₂O)₂Fe₂(5,5′-dmbipy)₂(CN)₈] · 2[Cu(bpca)Fe(5,5′-dmbipy)(CN)₄] · 4H₂O (4) and [Cu(bpca)Fe(4,4′-dmbipy)(CN)₄]_n (5) (bpca = bis(2-pyridylcarbonyl)amidate), have been synthesized and structurally characterized. Complex 4 contains two dinuclear and one tetranuclear heterobimetallic clusters in an asymmetric unit whereas the structure of complex 5 features a one-dimensional heterobimetallic zigzag chain. The Cu(II) ion is penta-coordinated in the form of a distorted square-based pyramid. Magnetic studies show ferromagnetic coupling between Cu(II) and Fe(III) ions with g = 2.28, J₁ = 2.64 cm^?1, J₂ = 5.40 cm^?1 and TIP = ?2.36 × 10^?3 for complex 4, and g = 2.17, J = 4.82 cm^?1 and zJ′ = 0.029 cm^?1 for complex 5.