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Five hexamolybdate and five octamolybdate-based organic–inorganic hybrid assemblies, with dioxomolybdenum(VI) hydrazonato complex cations, were synthesized from the [MoO2(acac)2] and isonicotinoyl hydrazone ligands bearing OH (H2L1,2) and OMe (H2L3,4) electron-donating groups. They can be classified into four categories including one known (i) [MoO2(HL1–4)(D)]2[Mo6O19]·xMeCN·yH2O, where D = H2O or MeCN, and three novel (ii) [Mo2O2(μ-O)2(HL3)2][Mo6O19], (iii) [MoO2(HL1,2)(H2O)]4[Mo8O26]·xMeCN·yH2O, and (iv) [MoO2(H2L2,4)(H2O)]2[Mo8O26]·xMeCN·yH2O, thus extending the structural landscape of Mo-complex–POM hybrids. Characterization of the hybrids, employing X-ray crystallography, IR-ATR, and TG analysis, was carried out. The effects of the reaction conditions and coordination nature of the Mo(VI) complex cations on the structure of the hybrid compounds were investigated. Relative differences in the standard Gibbs energies of formation () of the structures were calculated to determine the possibility of developing the covalently anchored POM–Mo-complex hybrids. The impact of the metal–organic components and various solvents on the particular type of hybrid formation was evaluated. [ABSTRACT FROM AUTHOR]

Symmetrical disubstituted carbohydrazides (H4L1–6) when reacted with [MoO2(acac)2] (in 1 : 2 molar ratio) afford the corresponding discrete complexes, [(MoO2)2L1,5,6(MeOH)2], [(MoO2)2L1,5,6(Im)2] (Im = imidazole), and/or polymeric ensembles, [(MoO2)2L1–6]n, depending on the reaction solvent, the ligand framework and the presence of ancillary coordinating species. In these assemblies, asymmetrical dimolybdenum(VI) entities, [(MoO2)2L1–6], wherein the corresponding carbohydrazide acts as an adaptable two-compartment ligand offering ONO and ONN coordination environments, serve as the main building blocks. The solid-state structures of the obtained materials were elucidated via X-ray diffraction and infrared spectroscopy, whereas the behaviour of polymeric ensembles in DMSO-d6 solution was investigated by nuclear magnetic resonance. Thermal studies revealed that the discrete species transform to the corresponding polymeric ensembles upon heating, whereas upon grinding they either remain intact or afford their reactive and coordinatively unsaturated (pentacoordinated) counterparts. While the discrete methanol-based complexes have a comparable spatial arrangement of ancillary ligands, imidazole-based ones offer substantially different scenario which was addressed in detail via density functional theory calculations. Finally, the polymeric ensembles were shown to be efficient catalysts for cyclooctene epoxidation under eco-friendly conditions while employing aqueous tert-butyl hydroperoxide as an oxidant. [ABSTRACT FROM AUTHOR]

The focus of this work was on the synthesis, characterization and catalytic activity of Mo(vi) complexes with hemilabile polydentate ligands that show a high tendency to form discrete small-sized self-assembled structures. A series of mononuclear, [MoO2(L1 or 3)(MeOH)] (1a and 3a) and [MoO2(L1)(EtOH)] (1b), and dinuclear, [MoO2(L1–3)]2 (1–3), complexes was synthesised by using 2-aminobenzoylhydrazone ligands derived from salicylaldehyde (H2L1), 3-methoxy-2-hydroxybenzaldehyde (H2L2) and 4-methoxy-2-hydroxybenzaldehyde (H2L3). Different reaction conditions led to the formation of several crystalline forms of the dinuclear cyclic species [MoO2(L1 or 3)]2 (1-α, 1-β, 1-γ, 1·CH3CN, 3-α, 3-β and 3·2CH3CN), a feature which is observed for the first time in the case of the metallosupramolecular compounds incorporating cis-MoO22+ subunits. These complexes were tested as catalysts for cyclooctene epoxidation under eco-friendly reaction conditions by using aqueous tert-butyl hydroperoxide as an oxidant without the addition of an organic solvent. The use of the hemilabile ligands provided the opportunity to employ relatively stable coordinatively saturated dinuclear Mo(vi) complexes, which in turn offered access to highly reactive pentacoordinated species in the presence of olefins. Lastly, the hemilabile ligand induced catalytic enhancement was addressed by using density functional theory calculations. [ABSTRACT FROM AUTHOR]

Cyclic dinuclear molybdenum(vi) complexes [MoO2(L1–3)]2 (1, 2-α, 2-β and 3) were synthesized through the use of coordination-driven self-assembly of a MoO22+ core and 4-aminobenzoylhydrazone ligands (salicylaldehyde (H2L1), 3-methoxysalicylaldehyde (H2L2) or 4-methoxysalicylaldehyde 4-aminobenzoylhydrazone (H2L3)). Their X-ray diffraction (XRD) analysis revealed that these types of ligands could serve as organic linkers for cis-octahedral complexes containing a MoO22+ core. Mononuclear complexes [MoO2(L1–3)(MeOH)] (1a–3a) and [MoO2(L1–3)(EtOH)] (1b, 2b-α, 2b-β and 3b) were also obtained. In the presence of strong donors, such as dmf, ligand substitution occurred and the structures of 1–3 changed into [MoO2(L1)(dmf)] (1c), [MoO2(L2)(dmf)] (2c) and [MoO2(L3)(H2O)]·dmf (3c·dmf), respectively. The dioxidomolybdenum(vi) complexes were tested for catalytic epoxidation of cyclooctene under eco-friendly reaction conditions by using aqueous tert-butyl hydroperoxide (TBHP) as an oxidant without the addition of an organic solvent. The present study showed much better activity of the dinuclear catalysts than the mononuclear ones due to the weak donor properties of the amino group and high geometric constraints occurring in such small sized self-assembled systems as confirmed by density functional theory calculations. [ABSTRACT FROM AUTHOR]

The dinuclear copper(ii) complexes [Cu2(LH)2] (1), [Cu2(L3OMe)2] (2), [Cu2(L4OMe)2] (3) as well as the tetranuclear complex [Cu4(L3OMe)4]·4MeOH·2H2O (2a·4MeOH·2H2O), (where LH = 2-oxybenzaldehyde benzhydrazonato, L3OMe = 3-methoxy-2-oxybenzaldehyde benzhydrazonato or L4OMe = 4-methoxy-2-oxybenzaldehyde benzhydrazonato) were synthesized by reacting copper(ii) acetate with the corresponding aroylhydrazone. Reactions in the presence of N-donor ligands D (pyridine, 4,4′-bipyridine or 1,10-phenanthroline) afforded complexes with different nuclearities and Cu : L : D ratios. They can be classified as dinuclear, [Cu2(LH)2(py)2] (1py), [Cu2(L3OMe)2(py)2]·3H2O (2py·3H2O), [Cu2(L4OMe)2(py)2] (3py), [{Cu(LH)}2(bpy)] (1bpy), [{Cu(L3OMe)}2(bpy)] (2bpy), and [{Cu(L4OMe)}2(bpy)] (3bpy), mononuclear [Cu(LH)(phen)] (1phen), [Cu(L3OMe)(phen)] (2phen) and [Cu(L4OMe)(phen)] (3phen), and polynuclear [{Cu(LH)}2(bpy)]n·2nMeOH (1bpy*·2MeOH) complexes. Conversion of complexes 1py–3py to complexes 1–3 proceeded via solid state reactions. The crystal and molecular structures of 2a·4MeOH·2H2O, 2py·3H2O, 3py, 1bpy*·2MeOH, 2bpy, 1phen and 3phen were determined by the single crystal X-ray diffraction method. All complexes were characterized by means of elemental and thermogravimetric analysis, FT-IR spectroscopy and the powder X-ray diffraction method. In vitro cytotoxicity of benzhydrazone-related ligands and their copper(ii) complexes against THP-1 and HepG2 cells demonstrated that the complexes are significantly more cytotoxic than the corresponding ligands. [ABSTRACT FROM AUTHOR]

A series of copper(ii) complexes with 4-hydroxybenzhydrazone-related ligands was synthesized by using various methods, including the conventional solution-based method, solvothermal route and electrochemical synthesis. The complexes can be classified as mononuclear [Cu(L3OMe)(py)] (2py), dinuclear [Cu2(LH)2(py)2] (1py), [Cu2(LH)2] (1α and 1β), [Cu2(LH)2(py)2] (1py), [Cu2(L4OMe)2(py)2] (3py), [Cu2(L4OMe)2] (3), [Cu2(L4OMe)2(MeOH)2] (3MeOH), [Cu2(L4OMe)2(EtOH)2] (3EtOH), cubane tetranuclear [Cu4(L3OMe)4]·xsolv (xsolv = 10H2O·CH3OH and 2.8EtOH·0.2H2O for 2MeOH and 2EtOH, respectively), or polynuclear [Cu(LH)(py)]n (1py*), where LH = 2-oxybenzaldehyde 4-hydroxybenzhydrazonato, L3OMe = 3-methoxy-2-oxybenzaldehyde 4-hydroxybenzhydrazonato, and L4OMe = 4-methoxy-2-oxybenzaldehyde 4-hydroxybenzhydrazonato ligands. The presented study indicates that complexes having different nuclearities and geometries can be achieved by changing the synthetic conditions and methods. Thermally induced structural transformations of the dinuclear complexes under solvent-free conditions were also investigated. Crystal and molecular structures of 1β, 1py*, 2MeOH, 2EtOH, 2py, 3 and 3MeOH were determined using the single crystal X-ray diffraction method. All complexes were characterized using microanalysis, FT-IR and CW-EPR spectroscopy, thermogravimetric analysis and a powder X-ray diffraction method. [ABSTRACT FROM AUTHOR]

Abstract: A new series of inorganic and organometallic cobalt Schiff base complexes containing the tetradentate ligand {[Z-Tyr(3-Ac)-OMe]2en} derived from the condensation of two equivalents of protected 3-acetyl-l-tyrosine with one equivalent of ethylenediamine has been synthesized. As the amino acids have l configuration, the resulting ligand is chiral. The complexes have been characterized by 1H and 13C NMR, ESI-MS spectrometry and UV–Vis spectroscopy. The UV–Vis spectra recorded in CH2Cl2 show an absorption band at about 650nm, characteristic of penta-coordinated alkylcobalt(III)(salen), but an evident deviation from the Lambert Beer law in the concentration range 0.20–2.0×10−3 M suggests some kind of association in this solvent. In coordinating solvent the complexes are hexa-coordinated. The equilibrium constants for pyridine ligation in CH3OH decrease with increasing electron-donor power of the axial alkyl group. Cyclic voltammetry studies indicate that after the reduction RCo(III)/RCo(II), the complexes decompose giving a Co(I) species that is stable on the CV time scale and can be reoxidized to Co(II) and Co(III) species. Both the E pa and the E pc values show that the peak potentials are shifted to more negative values with increasing inductive effect of the axial alkyl group. [Copyright &y& Elsevier]

Organic–inorganic hybrids, based on the Lindqvist-type polyoxometalate (POM) and dioxomolybdenum(vi) complexes, have been synthesized by hydrolysis of [MoO2(acac)2] (acac = acetylacetonate) in the presence of aroylhydrazone ligands in weak donor solvents. This provides an efficient route to materials that contain open coordination sites or sites occupied by labile ligands. Removal upon grinding or heating of the labile acetonitrile and acetone molecules on the dioxomolybdenum centres and the reaction in the solid-state represent a way for designing structures with the Lindqvist Mo6O192−anion coordinated to the metal centres of two complex cations. The compounds were characterised by the single crystal and powder X-ray diffraction methods, elemental analysis, IR spectroscopy, TG and DSC analyses. [ABSTRACT FROM AUTHOR]

The reaction of [MoO2(acac)2] (where acac = acetylacetonate ligand) with the salicylaldehyde isonicotinyl hydrazonate ligand (SIH2−) yielded a zigzag chain polymer [MoO2(SIH)]n (1), an interwoven hexagon [MoO2(SIH)]6 (2), or the mononuclear complexes [MoO2(SIH)(C2H5OH)] (3EtOH) and [MoO2(SIH)(C3H7OH)] (3PrOH). Diversity in the formation of dioxomolybdenum(VI) compounds illustrates their sensitivity to the reaction conditions. Crystal and molecular structures of all of the investigated molybdenum(VI) compounds were determined by the single crystal X-ray diffraction method. Solid-state reactions lead to the transformation of the supramolecular hexagon or the mononuclear complexes into the chain coordination polymer. These thermally induced conversions were characterized by the X-ray powder diffraction method. All of the investigated compounds were further characterized by elemental analysis, thermogravimetric analyses, Fourier transform infrared (FT-IR), and NMR spectroscopy. Substitution of the acetilyacetonate ligands in [MoO2(acac)2] by salicylaldehyde isonicotinyl hydrazonate (SIH2−) gives rise to zigzag chain polymer [MoO2(SIH)]n (1), interwoven hexagon [MoO2(SIH)]6 (2), or mononuclear complexes [MoO2(SIH)(C2H5OH)] (3EtOH) and [MoO2(SIH)(C3H7OH)] (3PrOH), depending on the reaction conditions. [ABSTRACT FROM AUTHOR]

The first structurally characterised oxomolybdenum(V) complexes with thienyl carboxylate ligands were prepared by the reaction of [Mo2O3(C5H7O2)4] or (NH4)2[MoOCl5] with the corresponding acid (2-thiophenecarboxylic, 5-methyl-2-thiophenecarboxylic or 3-(3-thienyl)acrylic acid). Complexes [Mo2O3(μ-OC2H5)(μ-O2CR)(C5H7O2)2](R = –C4H3S (1), –C4H2S(CH3) (2) or –CH＝CHC4H3S (3)) were obtained upon substitution of two acetylacetonate ligands from [Mo2O3(C5H7O2)4] with RCOO− in dry ethanol. Reactions of (NH4)2[MoOCl5] with the corresponding thienyl carboxylic acid in the presence of γ-picoline (C6H7N) yielded complexes (C6H7NH)[Mo2O4(μ-O2CR)Cl2(C6H7N)2] (R = –C4H3S (4), –C4H2S(CH3) (5) or –CH＝CHC4H3S (6)). All of the six new complexes were characterised as dinuclear. The molecular structures of 1, 3, 4·0.5CH3CN and 5 were determined by the single crystal X-ray diffraction method. In the complexes the two molybdenum atoms are doubly bridged either by one oxygen and one ethoxy-oxygen, or alternatively by two oxo-oxygens, and are additionally bridged by the thienyl carboxylate ion in a didentate bridging manner. All complexes were further characterised by means of chemical analysis, IR spectroscopy, TG and in some cases by the one and two-dimensional NMR method. [ABSTRACT FROM AUTHOR]

Abstract: New molybdenum complexes were prepared by the reaction of [MoVIO2(acac)2] or (NH4)2[MoVOCl5] with different N-substituted pyridoxal thiosemicarbazone ligands (H2L1 =pyridoxal 4-phenylthiosemicarbazone; H2L2 =pyridoxal 4-methylthiosemicarbazone, H2L3 =pyridoxal thiosemicarbazone). The investigation of monomeric [MoO2L1(CH3OH)] or polymeric [MoO2L1–3] molybdenum(VI) complexes revealed that molybdenum is coordinated with a tridentate doubly-deprotonated ligand. In the oxomolybdenum(V) complexes [MoOCl2(HL1–3)] the pyridoxal thiosemicarbazonato ligands are tridentate mono-deprotonated. Crystal and molecular structures of molybdenum(VI) [MoO2L1(CH3OH)]·CH3OH, and molybdenum(V) complexes [MoOCl2(HL1)]·C2H5OH, as well as of the pyridoxal thiosemicarbazone ligand methanol solvate H2L3 ·MeOH, were determined by the single crystal X-ray diffraction method. [Copyright &y& Elsevier]

Abstract: Eight new molybdenum(VI) complexes with 4-(diethylamino)salicylaldehyde and 2-hydroxy-3-methoxybenzaldehyde thiosemicarbazones have been prepared. They were characterized as mononuclear [MoO2LD] or dinuclear [{MoO2L}2D] complexes. In all the compounds the MoO2 2+ core is coordinated by a tridentate ONS thiosemicarbazonato ligand and by the N-donor molecule (imidazole, pyridine or γ-picoline). All the complexes were characterized by chemical analysis, IR spectroscopy and thermogravimetry. Three of the mononuclear complexes, dioxo[(2-hydroxy-3-methoxybenzaldehyde thiosemicarbazonato)(pyridine)]molybdenum(VI), dioxo[(2-hydroxy-3-methoxybenzaldehyde thiosemicarbazonato)(γ-picoline)]molybdenum(VI) and dioxo[(2-hydroxy-3-methoxybenzaldehyde thiosemicarbazonato)(imidazole)]molybdenum(VI) were also characterized by single-crystal X-ray structural analysis. A spectrophotometric method for the determination of molybdenum based on extraction of ion-pairs formed by the cationic surfactant and the [MoO(SCN)4]− anion is described. [Copyright &y& Elsevier]

Abstract: Mononuclear oxomolybdenum(V) complexes with thiosemicarbazonato ligands as condensation products of aldehydes (salicylaldehyde, 2-hydroxynaphthaldehyde) with thiosemicarbazides (H2NNHC:SNHR; R=H, CH3, C6H5) were prepared. The [MoOCl2HL] complexes (HL=thiosemicarbazonato ligand) were characterized by chemical analysis, IR spectroscopy, thermogravimetry and two of them, [MoOCl2{C6H4(O)CH:NNHC:SNHC6H5}] and [MoOCl2{C10H6(O)CH:NNHC:SNHC6H5}]·CH3CN, by single-crystal X-ray structural analysis. In both complexes the MoO3+ core is coordinated by a monobasic tridentate ONS thiosemicarbazonato ligand and two chloro ligands. The coordination around the molybdenum atom is a distorted octahedron. NH4[MoOCl4(CH3CN)] and unstable (C5H5NH)2[MoOCl5]·CH2Cl2 were isolated from the acetonitrile solution of (NH4)2[MoOCl5] and from the acetonitrile and dichloromethane (1:1) solution of (C5H5NH)2[MoOCl5], respectively. Isolation and structural characterization of NH4[MoOCl4(CH3CN)] from the acetonitrile solution suggests the [MoOCl4(CH3CN)]− anion to be the reaction intermediate in the synthesis of molybdenum(V) thiosemicarbazonato complexes. (C5H5NH)2[MoOCl5]·CH2Cl2 is a rare example of a structurally characterized simple oxohalomolybdate(V) with a six-coordinate octahedral [MoOCl5]2− anion. [Copyright &y& Elsevier]

Mononuclear molybdenum(VI) [MoO2L2] (1a, 1b, 2a, 2b) and dinuclear molybdenum(V) [Mo2O4(L1b)2(CH3OH)2] (3b) complexes have been prepared by the reaction of [MoO2(acac)2] or [Mo2O3(acac)4] (acac=acetylacetonate ion), respectively, with the appropriate β′-hydroxy-β-enaminones (HL). Also, two isomeric enaminones (HL1a and HL1b) have been prepared by the reaction of ethyl 2-hydroxy-4-(4-hydroxy-6-methyl-2H-pyran-2-on-3-yl)-4-oxo-2-butenoate (ehmpb) and o-anisidine. All the prepared molybdenum(VI) complexes are built up of mononuclear molecules with cis-MoO22+ cores, while the dinuclear molybdenum(V) complex contains a Mo2O42+ core. In all complexes ligand L is coordinated in a didentate fashion to molybdenum through two oxygen atoms and not through the nitrogen atom. One neutral solvent molecule CH3OH in the molybdenum(V) complex, acting as a monodentate ligand, completes the octahedral coordination of each Mo atom. All compounds have been characterized by means of chemical analyses, IR and one- and two-dimensional NMR spectroscopy. The molecular and crystal structures of the molybdenum(VI) (1a), molybdenum(V) (3b) complexes and of ligand HL1b have been determined by a single crystal X-ray diffraction method. [Copyright &y& Elsevier]

The oxalato complex of a polyoxomolybdovanadate, K 6 [Mo 6 V 2 O 24 (C 2 O 4 ) 2 ]·6H 2 O has been obtained by reaction of potassium molybdate, ammonium vanadate and tartaric or ascorbic acid. Such conversion of dicarboxylate into oxalate ions indicates the catalytic role of molybdenum. Complexes of analogous composition also were obtained in the reactions of MoO 3 , V 2 O 5 and potassium oxalate, or M 2 CO 3 ( M = Rb, Cs) and oxalic acid. The centrosymmetrical molybdovanadate anion [Mo 6 V 2 O 24 (C 2 O 4 ) 2 ] 6- consists of six MoO 6 and two VO 6 edge-sharing octahedra to give the γ-[Mo 6 O 26 ] 4- structure. All complexes were characterized by powder and single crystal X-ray analyses, ESR and IR spectra and TG and DSC measurements. [ABSTRACT FROM AUTHOR]

The reaction of [Co III (4,4′dmsalen)(CH 2 Cl)(L)], where 4,4′dmsalen = 4,4′-dimethylsalen and L = solvent, with pyridine led to the isolation of [Co III (4,4′dmsalen)(CH 2 py)(Cl)], in a two-step process involving a metallacyclized intermediate, cis β [Co III (4,4′dmsalenCH 2 )(py)(L)] + , whereas a parallel direct conversion through the displacement of a Cl atom from the axial CH 2 Cl group of [Co III (4,4′dmsalen)(CH 2 Cl)(L)] may be ruled out. Natural bond orbital analysis of the structures show that the ylide carbon atom has lower orbital occupancies in the cyclized complex, thus making it more susceptible to a nucleophilic attack of pyridine. The calculated potential energy surfaces indicate that the most energy feasible reaction path would be for the complex [Co III (4,4′dmsalenCH 2 )(py) ax (H 2 O)] + , with an entering pyridine molecule and a leaving equatorial water molecule. Experimental kinetic studies of the formation of the ylide complex starting from [Co III (4,4′dmsalenCH 2 )(py) eq (H 2 O)] + strongly suggest that it is possible to obtain the ylide complex through an alternative, less energetically favourable path. [ABSTRACT FROM AUTHOR]

The Schiff base pdxen ligands (H 2 py 2 en = N , N ′-ethylenebis(pyridoxylideneimine) and H 2 py 2 pren = N , N ′-prophylenebis(pyridoxylideneimine)) were found to form readily by the mechanochemical synthesis from their corresponding diamine and pyridoxal. Reduction of the Schiff bases with NaBH 4 yielded reduced pdxan ligands (H 2 Rpy 2 en = N , N ′-ethylenebis(pyridoxylamine) and H 2 Rpy 2 pren = N , N ′-prophylenebis(pyridoxylamine)). A dinuclear molybdenum(VI) complex with the bridging pdxen ligand [{MoO 2 } 2 ( μ -py 2 en)(OMe) 2 (MeOH) 2 ] ⋅ 3MeOH ( 1⋅3MeOH ), and mononuclear complexes with the pdxen ligand [MoO 2 (py 2 pren)] ( 3 ), as well as with the pdxan ligands: [MoO 2 (Rpy 2 en)] ( 2 ) and [MoO 2 (Rpy 2 pren)] ( 4 ) were prepared and characterized. Significant differences in the coordination of the Schiff base ligands were found as a consequence of chain length and ligand flexibility. Complexes 1 – 4 were obtained either by the reaction of [MoO 2 (acac) 2 ] or [Mo(CO) 6 ] with the corresponding ligands. Crystal and molecular structures of complexes 1⋅3MeOH , 2 and 3 were determined by the single crystal X-ray diffraction method. All complexes were characterized by microanalysis, FT-IR, NMR, UV, thermogravimetric analysis and powder X-ray diffraction method. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of [MoO2(acac)2] with hydrochloric salts of pyridoxal thiosemicarbazone ligands, H2L1–3·HCl, in dry methanol or acetonitrile resulted in the formation of the mononuclear complex [MoO2(HL1)(CH3OH)]Cl·1.5CH3OH (1a) or polynuclear complexes [{MoO2(HL1–3)}Cl] n (1–3) containing a different substituent on the nitrogen atom of the N-thioureide fragment: Ph (1 and 1a), Me (2) or H (3). New dinuclear molybdenum(V) complexes [Mo2O3(HL1–3)2]Cl2 (4–6) were obtained by oxygen atom abstraction from 1–3 with triphenylphosphine. All compounds were characterized by chemical analysis, IR spectroscopy, one- and two-dimensional NMR methods, TGA and in selected cases by DSC measurements. In addition, the crystal and molecular structure of 1a was determined by single crystal X-ray diffraction. All molybdenum(VI) species were used as (pre)catalysts for olefin epoxidation under solvent-free conditions with a 0.05% Mo loading versus olefin. [Copyright &y& Elsevier]

Describes the synthesis and the characterization of several organocobalt derivatives with a salen-type ligand. Oxidative addition of CH[sub 2]CII; Intramolecular reaction of the axial chloromethy; Formation of the monocationic complex; Comparison of the geometry of the planar salicylaldiminate moiety with cyclized methoxy-iminate one.