Elektrochemische Synthese von Kupfernitrilkomplexen

Electrochemical Synthesis of Copper Nitrile Complexes Electrochemical syntheses of copper nitrile complexes by anodic dissolution of copper and cathodic reduction of malonodinitrile in a one‐step reaction are reported. In the presence of different donors the following compounds are obtained and characterized analytically: {[Cu₂(μ‐CN) · (CH₃CN)₃]CH(CN)₂}_n ( 1 ), {[Cu₂(μ‐CN)(PPh₃)₄]CH(CN)₂}_n ( 2 ) and [Cu₂(μ‐CN)(phen)₂(PPh₃)₂]CH(CN)₂ ( 3 ). As a result of an X‐ray analysis, 3 proved to be an ionic binuclear complex in which the cyano‐bridged Cu^I atoms have distorted tetrahedral coordination sphere. Both the CN group and the dicyanomethanid anion are disordered about centres of inversion.     

Reactions of cationic rhodium(I) carbonyl compounds with nucleophiles to form alkoxo,carboalkoxy and carboxylato complexes. Part II

Summary The rhodium(I) carbonyl compounds [Rh(CO)L₂2] [BF₄]. 1/2CH₂Cl_nn2 (L = PPh₂ or AsPh₃) react with the nucleophiles OMe⁻, RCOO⁻ (R = Me, Et) under nitrogen to form [Rh(OR)(CO)L₂] (1)–(2) and [Rh(OOCR)(CO)L₂] (7)–(₁₀), respectively. Addition of [Rh(CO)₂(PPh₃)₂]-[BF ₄] to OMe⁻ under nitrogen produces [Rh(COOMe)-(CO) (PPh₃)₂]-MeOH (3), whilst reactions of [Rh(CO)-(PPh₃)₂] [BF₄]·1/2CH₂Cl₂ and [Rh(CO)₂(PPh₃)₂] [BF₄] with OR_- (R = Me, Et or n-Pr) in the presence of CO produce [Rh(COOR)(CO)₂(PPh₃)₂] (4)–(6). The products have been characterised by i.r., ¹H, ³¹P, ¹³Cn.m.r. spectroscopy and elemental analysis.     

Syntheses,structures, and magnetic properties of dinuclear/1-D copper(II) acetato and formato derivatives with methylpyrazine and dimethylpyrazine

In this study, {[Cu₂(µ-HCO₂)₄](µ-Mepyrz)} _n (1), [Cu₂(µ-HCO₂)₄(Mepyrz)₂] (2), {[Cu₂(µ-AcO)₄](µ-Mepyrz)} _n (3), [Cu₂(µ-AcO)₄(Mepyrz)₂] (4), [Cu₂(µ-AcO)₄(2,3-Me₂pyrz)₂] (5), [Cu₂(µ-AcO)₄(2,6-Me₂pyrz)₂] (6), and {[Cu₂(µ-AcO)₄](µ-2,5-Me₂pyrz)} _n (7) have been synthesized and characterized by chemical analysis and electronic spectroscopy. Compounds 2, 4, 5, and 6, characterized by single-crystal X-ray diffraction, are composed of molecular dimers based on a paddle-wheel motif with two coppers, four syn–syn carboxylates, and two ligands coordinated to copper in the axial positions. In 7, chains of [Cu₂(µ-AcO)₄] dimers with 2,5-Me₂pyrz as bridging ligands are formed. Magnetic properties and electron paramagnetic resonance results of the compounds are also described.     

Synthesis,spectroscopic investigation,structural characterization,and DFT calculations of [ReX2(N2COPh)(CH3PhCN)(PPh3)2] (X=Cl,Br)

Reactions of [ReX₂(η ²-N₂COPh-N′,O)(PPh₃)₂] with 3-methylbenzonitrile give two iso-structural complexes, [ReX₂(N₂COPh)(CH₃PhCN)(PPh₃)₂] (X?=?Cl, Br). The crystal and molecular structures of [ReCl₂(N₂COPh)(CH₃PhCN)(PPh₃)₂] (1) and [ReBr₂(N₂COPh)(CH₃PhCN)(PPh₃)₂]?·?CH₂Cl₂ (2) were determined. The electronic structures were examined with density functional theory (DFT). The spin-allowed electronic transitions were calculated with the time-dependent DFT method, and the UV-Vis spectrum has been discussed.     

Syntheses,structures and fluorescent properties of three copper cyanide coordination polymers based on N-heterocyclic ligands

Hydrothermal reactions of CuCN, K₃[Fe(CN)₆] with 2,2′-bipyridine, 1,10-phenanthroline or 2,6-bis(1,2,4-triazolyl)pyridine (btp) afford three coordination polymers, [Cu₇(CN)₇(bipy)₂] _n (1), [Cu₂(CN)₂(phen)] _n (2) and [Cu₃(CN)₃(btp)] _n (3). Complex 1 displays 1D polymeric ribbons which are assembled through Cu ··· Cu and π–π stacking interactions into a 3D framework. Complex 2 shows a 1D zigzag chain structure in which phen is a side ligand. In 3, the copper cyanide 2D polymeric networks are connected by tridentate btp to form a 3D metal-organic framework. These coordination polymers exhibit strong fluorescent emissions in the solid state.     

Electrochemical Synthesis of Tricyanomethyl Copper Complexes

The synthesis of tricyanomethyl copper complexes has been achieved by anodic dissolution of a sacrificial copper metal and cathodic reduction of 1, 1, 3, 3‐tetracyanopropane in acetonitrile, in the presence of triphenylphosphane used as coligand. The electrogenerated tetracyanopropyl radical anion is not stable and undergoes a cleavage leading to the tricyanomethyl anion and acrylonitrile which is electropolymerized at the cathode. The reaction solution gives a neutral dimeric binuclear copper(I) complex, bis{(μ‐ tricyanomethanido)bis(triphenylphosphane)copper(I)} [Cu(μ‐C(CN)₃)(PPh₃)₂]₂ ( 1 ). A second product of the synthesis reacts with 1, 10‐phenanthroline to give bis{cis‐(μ‐cyano)bis(triphenylphos‐phane)bis(phenanthroline)dicopper(I)}‐tricyanomethanide‐tetrafluoroborate‐diacetonitrile [cis‐{Cu₂(μ‐CN)(Phen)₂(PPh₃)₂}]₂[C(CN)₃] · BF₄ · 2CH₃CN ( 2 ). The crystal structures of 1 and 2 were determined by X‐ray analysis.     

Spectroscopic Study of the Interaction of the Pd(acac)(C3-acac)PPh3Complex with BF3OEt2 in the Presence of PPh3

The interaction between the components of a catalytic system Pd(acac)(C³-acac)PPh₃+nPPh₃+ mBF₃OEt₂(where n= 1–4, m= 0.25–4, and acac is the acetylacetonate ligand) in benzene is examined by UV and IR spectroscopy. With a relative excess of PPh₃(n> m), acacH and [Pd(acac)(PPh₃)₂]⁺BF^– ₄were the main products, whereas BF₂acac and a polynuclear complex of PdF₂with PPh₃also containing Pd²⁺(BF^– ₄)₂units were formed with a relative excess of BF₃OEt₂(n< m).     

Further investigations on the methylation chemistry of [Pt2(µ-S)2(PPh3)4]

The methylation product of the reaction between [Pt₂(µ-S)₂(PPh₃)₄] and MeI in diethyl ether has been reinvestigated using positive-ion electrospray mass spectrometry and found to be contaminated with the dimethylated iodide-containing complex [Pt₂(µ-SMe)₂(PPh₃)₃I]⁺, which is believed to be formed early in the reaction. New, facile routes to the monomethylated complex [Pt₂(µ-S)(µ-SMe)(PPh₃)₄]⁺ have been developed using mild methylating agents. Heating [Pt₂(µ-S)₂(PPh₃)₄] in neat dimethyl methylphosphonate results in rapid and selective conversion to [Pt₂(µ-S)(µ-SMe)(PPh₃)₄]⁺; methylation with Me₃S⁺OH^? in refluxing methanol also affords pure [Pt₂(µ-S)(µ-SMe)(PPh₃)₄]⁺, isolated as its hexafluorophosphate salt. The X-ray structure of the previously reported complex [Pt₂(µ-SMe)₂(PPh₃)₂I₂] has also been undertaken.     

Structural characterization,DFT studied,luminescent properties of cationic/neutral three-coordinated copper (I) complexes and application in warm-white light-emitting diode

A series of cationic/neutral copper (I) complexes, [Cu₂(Hbmb)(PPh₃)₄] (BF₄)₂ ( 1a ), [Cu₂(Hbmb)(DPEPhos)₂](BF₄)₂ ( 2a ), [Cu₂(Hbmb)(Xantphos)₂](BF₄)₂ ( 3a ), [Cu₂(bmb)(PPh₃)₄] ( 1b ), [Cu₂(bmb)(DPEPhos)₂] ( 2b ), [Cu₂(bmb)(Xantphos)₂] ( 3b ) (Hbmb = 1,4-bis (1H-benzimidazol −2-yl)benzene, PPh₃ = triphenylphosphine, DPEPhos = bis[2-(diphenylphosphino)-phenyl]ether, Xantphos =4,5-bis (diphenylphosphino)-9,9′-dimethyl-xanthene), have been synthesized and characterized by IR, TGA, XRD and X-ray crystal structure analysis. The structural analysis reveals that each Cu⁺ in all complexes adopts an almost ideal trigonal planar geometry, with three coordinate NP₂, and the C-H···π and π···π interactions are observed in the packing structures. DFT studied indicate the ingredients of the HOMOs and LUMOs for neutral copper (I) complexes 1b , 2b and 3b are different from cationic copper (I) complexes 1a , 2a and 3a , in accordance with the distribution of Mülliken atomic charges. Meanwhile, neutral copper (I) complexes 1b , 2b and 3b have fascinating broad blue-green emission bands at room temperature, while cationic copper (I) complexes 1a , 2a and 3a exhibit the existence of multiple emission peaks. Furthermore, the maximum phosphorescent lifetime and quantum yield at room temperature, for all copper (I) complexes, are 1143 μs and 8.82%, respectively. In addition, in order to measure the practical application of these complexes, the selection of complex 1b is used to fabricate the LED, which emits a bright warm-white light.     

Studies of η5-cyclichydrocarbon ruthenium(II) complexes containing para-amino-N-(pyrid-2-ylmethylene)phenylamine ligand: molecular structure of [(η5-C5H5)Ru(PPh3)(C5H4NCH=N-C6H4-p-NH2)]BF4

Reaction of [(η⁵-Cp)Ru(PPh₃)₂Cl] (1) with excess para-amino-N-(pyrid-2-ylmethylene)-phenylamine ligand (app) in methanol in the presence of NH₄BF₄ leads to the formation of [η⁵-CpRu(PPh₃)(aap)]BF₄ (6BF₄). Similarly, [(η⁵-ind)Ru(PPh₃)₂(CH₃CN)]BF₄ (4BF₄) and [(η⁵-Cp*)Ru(PPh₃)₂(CH₃CN)]BF₄ (5BF₄) react with app to yield the cationic complexes [(η⁵-ind)Ru(PPh₃)(app)]BF₄ (7BF₄) and [(η⁵-Cp*)Ru(PPh₃)(app)]BF₄ (8BF₄), respectively. The complexes were characterized by analysis and spectroscopic data. The structure of a representative complex (6BF₄) was established by single-crystal X-ray methods.     

Ligand-directed copper(І) azide coordination polymers bridged by N-donor ligands with different lengths: azide exhibits a rare μ−1, 1, 3, 3 bridging mode

A Ligand-Directed strategy has been adopted to synthesize three novel Copper(І) coordination polymers, [Cu₂(bpe)(N₃)₂] _n (1), [Cu₂(bpy)(N₃)₂] _n (2), and [Cu₄(py)(N₃)₄] _n (3), by the reactions of NaN₃ with bpe, bpy and py (bpe = 1,2-trans-(4-pyridyl)ethene, bpy = 4,4′-bipyridine, py = pyrazine) in the presence of H₃PO₃ under hydrothermal conditions, which proved that the length of ligands had subtle effects on overall network and the coordination mode of azide.     

Chalkogenoniobate als Ausgangsverbindungen zur Darstellung neuer heterobimetallischer Niobium‐Münzmetall‐Chalkogenido‐Cluster

Chalcogenoniobates as Reagents for the Synthesis of New Heterobimetallic Niobium Coinage Metal Chalcogenide Clusters In the presence of phosphine chalcogenoniobates such as Li₃[NbS₄] · 4 CH₃CN ( I ), (NEt₄)₄[Nb₆S₁₇] · 3 CH₃CN ( II ) and (NEt₄)₂[NbE′₃(E^tBu)] ( III a : E′ = E = S; III b : E = Se, E′ = S; III c : E = E′ = Se) respectively react with copper and gold salts to give a number of new heterobimetallic niobium copper(gold) chalcogenide clusters. These clusters show metal chalcogenide units already known from the complex chemistry of the tetrachalcogenometalates [ME₄]^n– (M = V, n = 3, E = S; M = Mo, W, n = 2, E = S, Se). The compounds 1 – 8 owe a central tetrahedral [NbE₄] structural unit, which coordinates η² from two to five coinage metal atoms, employing the chalcogenide atoms of the [NbE₄] edges. The compounds 9 – 11 have a [M′₂Nb₂E₄] (M′ = Cu, Au) heterocubane unit in common, involving a metal metal bond between the niobium atoms, while the compounds 12 and 13 show a complete and 14 an incomplete [M′₃NbE₃X] heterocubane structure (X = Cl, Br). 15 consists of a Cu₆Nb₂ cube with the six planes capped by μ₄ bridging selenide ligands forming an octahedra. The compounds 1 – 15 are listed below: (NEt₄) [Cu₂NbSe₂S₂(dppe)₂] · 2 DMF ( 1 ), [Cu₃NbS₄(PPh₃)₄] ( 2 ), [Au₃NbSe₄(PPh₃)₄] · Et₂O ( 3 ), [Cu₄NbS₄Cl(PCy₃)₄] ( 4 ), [Cu₄NbS₄Cl(P^tBu₃)₄] · 0,5 DMF ( 5 ), [Cu₄NbSe₄(NCS)(P^tBu₃)₄] · DMF ( 6 ), [Cu₄NbS₄(NCS)(dppm)₄] · Et₂O ( 7 ), [Cu₅NbSe₄Cl₂‐ (dppm)₄] · 3 DMF ( 8 ), [Cu₂Nb₂S₄Cl₂(PMe₃)₆] · DMF ( 9 ), [Au₂Nb₂Se₄Cl₂(PMe₃)₆] · DMF ( 10 ), (NEt₄)₂[Cu₃Nb₂S₄(NCS)₅(dppm)₂(dmf)] · 4 DMF ( 11 ), [Cu₃NbS₃Br(PPh₃)₃(dmf)₃]Br · [CuBr(PPh₃)₃] · PPh₃ · OPPh₃ · 3 DMF ( 12 ), [Cu₃NbS₃Cl₂(PPh₃)₃(dmf)₂] · 1.5 DMF ( 13 ), (NEt₄)[Cu₃NbSe₃Cl₃(dmf)₃] ( 14 ), [Cu₆Nb₂Se₆O₂(PMe₃)₆] ( 15 ). The structures of these compounds were obtained by X‐ray single crystal structure analysis.     

Syntheses and structures of three new coordination polymers with the flexible 1,4- bis (imidazol-1-yl)butane ligand

Three new coordination polymers [Co(bimb)₂(NCS)₂] _n (1), {[Co(bimb)₂(dca)₂]?·?CH₃CN} _n (2) and [Cu(bimb)₂(NO₃)₂] _n (3) (bimb?=?1,4-bis(imidazol-1-yl)butane, dca?=?dicyanamide) were synthesized and characterized. In 1, each Co(II) links two Co(II)'s by double bimb ligands and extends to form a one-dimensional chain containing the Co₂(bimb)₂ 22-membered metallocycle. 2 and 3 are two-dimensional (4, 4) networks linked by bimb bridges. The conformations of the bimb ligands in 1, 2 and 3 are analyzed.     

Hydrothermal synthesis and characterization of LaIII and CuII coordination polymers with 5-nitroisophthalic acid (H2Nip), [La2(μ-Nip)(μ-SO4)2(H2O)5] n and {[Cu3(μ-OH)2(μ-Nip)2(μ-H2O)2] · 2H2O} n

3D La^III and 2D Cu^II coordination polymers with 5-nitroisophthalate anions, [La₂(μ-Nip)(μ-SO₄)₂(H₂O)₅] _n (1) and {[Cu₃(μ-OH)₂(μ-Nip)₂(μ-H₂O)₂] ·?2H₂O} _n (2), have been synthesized, characterized and studied by X-ray crystallography. The La atoms have eight–coordinate geometries in distorted square antiprism environments and the Cu atoms have five- and six–coordinate geometries with distorted square pyramidal and octahedral environments. Self-assembly of these compounds in the solid state occurs through coordination and hydrogen bonding.     

3,5-二烷基-1,2,4-三唑衍生物构筑的两个Cu4I4簇配合物的合成、结构和荧光性质

以3,5-二甲(丙)基-4-氨基-1,2,4-三唑为配体,与CuI在H₂O/MeCN混合溶剂热合成了2个构型不同的Cu₄I₄超分子化合物{[Cu₂(aadmtrz) I₂]·CH₃CN}_n(1)和[Cu₂(dptrz) I]_n(2)(aadmtrz=4-((1-氨乙基)-氨基)-3,5-二甲基-1,2,4-三唑,dptrz=3,5-二丙基-1,2,4-三唑),并进行了元素分析,红外,X射线粉末衍射及单晶衍射等表征。2个配合物中Cu₄I₄构型不同,配合物1中,Cu₄I₄簇连结成一个8环椅式-椅式结构,通过配体连接成(4,4)二维菱形格子结构;而配合物2中,Cu₄I₄簇呈畸变的立方烷结构,构成了含有19.5%孔隙率三维孔洞聚合物,其结构可简化为(3,4)-连接的拓朴结构。同时,在常温下研究了2个配合物的固体荧光性质。     

Altering the Activity of Catechol Oxidase Model Compounds by Electronic Influence on the Copper Core

The catecholase activity of the dicopper(II) complexes [Cu₂(L¹)(μ‐OCH₃)(NCCH₃)₂](PF₆)₂·H₂O·CH₃CN ( 1 ), [Cu₂(L²)(μ‐OH)(MeOH)(NCCH₃)](BF₄)₂ ( 2 ), [Cu₂(L³)(μ‐OMe)(NCCH₃)₂](BF₄)₂·2CH₃CN·H₂O ( 3 ), [Cu₂(L²)(μ‐OAc)₂]BF₄·H₂O ( 4 ), [Cu₂(L⁴)(μ‐OAc)₂]ClO₄ ( 5 ) and [Cu₂(L⁵)(μ‐OMe)(NCCH₃)₃(OH₂)](ClO₄)₂·2CH₃OH·CH₃CN ( 6 ) consisting of varying para‐substituted phenol ligands HL¹ = 4‐trifluoromethyl‐2,6‐bis((4‐methylpiperazin‐1‐yl)methyl)phenol, HL² = 4‐bromo‐2,6‐bis((4‐methyl‐1,4‐diazepan‐1‐yl)methyl)phenol, HL³ = 4‐bromo‐2‐((4‐methyl‐1,4‐diazepan‐1‐yl)methyl)‐6‐((4‐methylpiperazin‐1‐yl)methyl)phenol, HL⁴ = 2,6‐bis((4‐methylpiperazin‐1‐yl)methyl)‐4‐nitrophenol and HL⁵ = 4‐tert‐butyl‐2,6‐bis((4‐methylpiperazin‐1‐yl)methyl)phenol was studied. The main difference within the six complexes lies in the individual copper–copper separation that is enforced by the chelating side arms of the phenolate ligand entity and more importantly in the exogenous bridging solvent, hydroxide, methanolate or acetate ions. The distance between the copper cores varies from 2.94Å in 1 to 3.29Å in 5 . The catalytic activity of the complexes 1 – 6 towards the oxidation of 3,5‐di‐tert‐butylcatechol was determined spectrophotometrically by monitoring the increase of the 3,5–di‐tert‐butylquinone characteristic absorption band at about 400 nm over time saturated with O₂. The complexes are able to oxidize the substrate 3,5‐di‐tert‐butylcatechol to the corresponding o‐quinone with distinct catalytic activity (k_cat between 92 h^?1 and 189 h^?1), with an order of decreasing activity 6 > 5 > 1 , 2 , 4 ≥ 3 . A kinetic treatment of the data based on the Michaelis‐Menten approach was applied. A correlation of the catecholase activities with the variation of the para‐ substituents as well as other effects resulting from the copper core distances is discussed. [Cu₂(L⁵)(μ‐OMe)(NCCH₃)₃(OH)₂](ClO₄)₂·2CH₃OH·CH₃CN ( 6 ) exhibited the highest activity of the six complexes as a result of its high turnover rate.     

Synthesis and structural characterization of ruthenium complexes with 1-aryl-imidazole-2-thione

Treatment of [RuCl₂(PPh₃)₃] with 2 equiv. Himt^MPh (Himt^MPh?=?1-(4-methyl-phenyl)-imidazole-2-thione) in the presence of MeONa afforded cis-[Ru(κ ²-S,N-imt^MPh)₂(PPh₃)₂] (1), while interaction of [RuCl₂(PPh₃)₃] and 2 equiv. Himt^MPh in tetrahydrofuran (THF) without base gave [RuCl₂(κ ¹-S-Himt^MPh)₂(PPh₃)₂] (2). Treatment of [RuHCl(CO)(PPh₃)₃] with 1 equiv. Himt^MPh in THF gave [RuHCl(κ ¹-S-Himt^MPh)(CO)(PPh₃)₂] (3), whereas reaction of [RuHCl(CO)(PPh₃)₃] with 1 equiv. of the deprotonated [imt^MPh]^? or [imt^NPh]^? (imt^NPh?=?1-(4-nitro-phenyl)-2-mercaptoimidazolyl) gave [RuH(κ ²-S,N-imt^RPh)(CO)(PPh₃)₂] (R?=?M 4a, R?=?N 4b). The ruthenium hydride complexes 4a and 4b easily convert to their corresponding ruthenium chloride complexes [RuCl(κ ²-S,N-imt^MPh)(CO)(PPh₃)₂] (5a) and [RuCl(κ ²-S,N-imt^NPh)(CO)(PPh₃)₂] (5b), respectively, in refluxing CHCl₃ by chloride substitution of the RuH. Photolysis of 5a in CHCl₃ at room temperature afforded an oxidized product [RuCl₂(κ ²-S,N-imt^MPh)(PPh₃)₂] (6). Reaction of 6 with excess [imt^MPh]^? afforded 1. The molecular structures of 1·EtOH, 3·C₆H₁₄, 4b·0.25CH₃COCH₃, and 6·2CH₂Cl₂ have been determined by single-crystal X-ray crystallography.     

Copper coordination polymers from cavitand ligands: hierarchical spaces from cage and capsule motifs,and other topologies

The cyclotriveratrylene-type ligands (±)-tris(iso-nicotinoyl)cyclotriguaiacylene L1 (±)-tris(4-pyridylmethyl)cyclotriguaiacylene L2 and (±)-tris{4-(4-pyridyl)benzyl}cyclotriguaiacylene L3 all feature 4-pyridyl donor groups and all form coordination polymers with Cu^I and/or Cu^II cations that show a remarkable range of framework topologies and structures. Complex [Cu^I ₄Cu^II _1.5(L1)₃(CN)₆]·CN·n(DMF) 1 features a novel 3,4-connected framework of cyano-linked hexagonal metallo-cages. In complexes [Cu₃(L2)₄(H₂O)₃]·6(OTf)·n(DMSO) 2 and [Cu₂(L3)₂Br₂(H₂O)(DMSO)]·2Br·n(DMSO) 3 capsule-like metallo-cryptophane motifs are formed which linked through their metal vertices into a hexagonal 2D network of (4³.12³)(4².12²) topology or a coordination chain. Complex [Cu₂(L1)₂(OTf)₂(NMP)₂(H₂O)₂]·2(OTf)·2NMP 4 has an interpenetrating 2D 3,4-connected framework of (4.6².8)(6².8)(4.6².8²) topology with tubular channels. Complex [Cu(L1)(NCMe)]·BF₄·2(CH₃CN)·H₂O 5 features a 2D network of 6³ topology while the Cu^II analogue [Cu₂(L1)₂(NMP)(H₂O)]·4BF₄·12NMP·1.5H₂O 6 has an interpenetrating (10,3)-b type structure and complex [Cu₂(L2)₂Br₃(DMSO)]·Br·n(DMSO) 7 has a 2D network of 4.8² topology. Strategies for formation of coordination polymers with hierarchical spaces emerge in this work and complex 2 is shown to absorb fullerene-C₆₀ through soaking the crystals in a toluene solution.     

Reactivity of cationic methyl rhodium(III) complexes cis-[Rh(β-diket)(PPh3)2(CH3)(CH3CN)][BPh4] toward ligands of different character: pyridine, carbon monoxide, and triphenylphosphine

Cationic methyl complex of rhodium(III), cis-[Rh(Acac)(PPh₃)₂(CH₃)(Py)][BPh₄] (1) as a single isomer with Py in the trans to PPh₃ position, is formed upon the reaction of cis-[Rh(Acac)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] with pyridine in methylene chloride solution.Complex 1 was characterized by elemental analysis and by ³¹P{¹H} and ¹H NMR spectra.Cationic pentacoordinate acetyl complexes, trans-[Rh(Acac)(PPh₃)₂(COCH₃)][BPh₄] (2) and trans-[Rh(BA)(PPh₃)₂(COCH₃)][BPh₄] (3), are prepared by action of carbon monoxide on cis-[Rh(Acac)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] and cis-[Rh(BA)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄], respectively, in methylene chloride solutions.Complexes 2 and 3 were characterized by elemental analysis and by IR, ³¹P{¹H}, ¹³C{¹H} and ¹H NMR. According to NMR data, 2 and 3 in solution are non-fluxional trigonal bipyramids with β-diketonate and acetyl ligands in the equatorial plane and axial phosphines.In solutions, 2 and 3 gradually isomerize into octahedral methyl carbonyl complexes trans-[Rh(Acac)(PPh₃)₂(CO)(CH₃)][BPh₄] (4) and trans-[Rh(BA)(PPh₃)₂(CO)(CH₃)][BPh₄] (5), respectively.Complexes 4 and 5 were characterized by IR, ³¹P{¹H}, ¹³C{¹H} and ¹H NMR, without isolation.Upon the action of PPh₃ on cis-[Rh(Acac)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] and cis-[Rh(BA)(PPh₃)₂(CH₃)(CH₃CN)] [BPh₄], reductive elimination of the methyl ligand as a phosphonium salt, [CH₃PPh₃][BPh₄], occurs to give square planar rhodium(I) complexes [Rh(Acac)(PPh₃)₂] and[Rh(BA)(PPh₃)₂], respectively. The reaction products were identified in the reaction mixtures by ³¹P{¹H} and ¹H NMR.     

One-dimensional cyanide-bridged Fe(III)–Mn(II) magnetic complexes with different configurations derived from a new pentacyanoiron(III) building block

Two cyanide-bridged heterometallic Fe^III–Mn^II complexes with formula {[Mn(bipy)(H₂O)]₂[Fe(2-CH₃im)(CN)₅]₂}_n·nCH₃OH·4nH₂O (2) (bipy?=?2,2′-bipyridine) and {[Mn(MAC)][Fe(2-CH₃im)(CN)₅]}_n·nDMF·3nH₂O (3) (MAC?=?2,13-dimethyl-3,6,9,12,18-pentaazabicyclo-[12.3.1]octadeca-1(18),2,12,14,16-pentaene) have been successfully synthesized by assembling a newly designed pentacyanoiron(III) precursor [PPh₄]₂[Fe(CN)₅(2-CH₃im)]·2CH₃OH (1) and two Mn(II) compounds containing bulky ancillary organic ligands as segments, and characterized by elemental analysis, infrared (IR) spectroscopy, and X-ray structure determination. X-ray diffraction analysis revealed one-dimensional (1D) ladder-like double or linear single infinite-chain structures for complex 2 and 3, respectively, indicating the obvious steric influence of the auxiliary ligand(s) on the structural type. Experimental and theoretical investigations on the magnetic properties of the complexes showed the antiferromagnetic coupling between the cyanide-bridged low-spin Fe(III) ion and high-spin Mn(II) ion.