Crystal Structure of Bis -(2,2′-bipyridine-N,N′)-(dicyanamide-N)-copper(II) Tricyanomethanide. Electronic and Structural Parameters Describing the Shape of Coordination Polyhedra in Five-Coordinated Copper(II) Compounds

 The structure of the new compound [Cu(bpy)₂N(CN)₂]C(CN)₃ (6) is compared with thestructures of six copper(II) coordination compounds with phenanthroline or bipyridine ligands and N-donor pseudohalide anions: [Cu(phen)₂NCS]C(CN)₃ (1), [Cu(bpy)₂NCS]C(CN)₃ (2), [Cu(phen)₂NCS]ONC(CN)₂ (3), [Cu(phen)₂N(CN)₂]C(CN)₃ (4), [Cu(bpy)₂C(CN)₃]C(CN)₃ (5), and [Cu(bpy)₂NCO]C(CN)₃ (7). The Cu(II) atoms in all above compounds are five-coordinated with an N-donor atom of the pseudohalide anion located in the equatorial plane of a deformed trigonal bipyramid. The shape of the coordination polyhedra and the degree of trigonal bipyramidal distortion towards a tetragonal pyramid are discussed and described using one electronic and several structural criteria which are discussed and compared.     

Crystal Structure of Bis-(2,2′-bipyridine-N,N′)-(dicyanamide-N)-copper(II) Tricyanomethanide. Electronic and Structural Parameters Describing the Shape of Coordination Polyhedra in Five-Coordinated Copper(II) Compounds

Summary.  The structure of the new compound [Cu(bpy)₂N(CN)₂]C(CN)₃ (6) is compared with thestructures of six copper(II) coordination compounds with phenanthroline or bipyridine ligands and N-donor pseudohalide anions: [Cu(phen)₂NCS]C(CN)₃ (1), [Cu(bpy)₂NCS]C(CN)₃ (2), [Cu(phen)₂NCS]ONC(CN)₂ (3), [Cu(phen)₂N(CN)₂]C(CN)₃ (4), [Cu(bpy)₂C(CN)₃]C(CN)₃ (5), and [Cu(bpy)₂NCO]C(CN)₃ (7). The Cu(II) atoms in all above compounds are five-coordinated with an N-donor atom of the pseudohalide anion located in the equatorial plane of a deformed trigonal bipyramid. The shape of the coordination polyhedra and the degree of trigonal bipyramidal distortion towards a tetragonal pyramid are discussed and described using one electronic and several structural criteria which are discussed and compared. Received July 24, 2000. Accepted October 18,2000     

Two diamond-type octacyanometallate(IV)–nickel(II) assemblies chelated by macrocyclic ligands

Two octacyanometallate-based Ni^II–M^IV [M?=?Mo(1), W(2)] bimetallic assemblies chelated with tetradentate macrocyclic ligands have been synthesized by slow diffusion and characterized structurally. In both complexes, M and Ni centers acting as linker and connector, respectively, are connected by M–CN–Ni–NC–M linkages to form a 3-D diamond-type topological network. Magnetic behaviors of both complexes show a very weak antiferromagnetic interaction between Ni^II ions mediated by the diamagnetic [M(CN)₈]^4? bridges.     

Azacrownlactams Derived from Biphenyl. Study of Their Conformations, Complexation Ability and Electrochemical Behavior

Several macrolactams containing in their structure biphenyl and pyridine moieties have been synthesized. The complexation ability of these compounds has been evaluated and the results have been explained considering the existence of intramolecular hydrogen bonds. Conformational studies have been developed in some cases. Single-crystal X-ray diffraction studies have been carried out with one of the ligands. The electrochemical response of ligands 1 and 3 has been studied using cyclic and square wave voltammetry. The interaction of these ligands with Cu²⁺ ions in CH₃CN has been investigated by electrochemical techniques.     

OXIDATIVE ADDITION OF SOME HALOGENS,INTERHALOGENS AND PSEUDOHALOGENS TO [(n-C4H9)4N]2[Pt(CN)4]

Abstract

The results of the treatment of [(n–C₄H₉)₄N]₂ [Pt(CN)₄] with seventeen oxidizing agents, including halogens, inter halogens, and molecules such as N₂O₄, ICN, (SCN)₂, S(CN)₂ and C₆ H₅SCl, are reported. In cases where the reagents were not symmetrical molecules, two different ligands were added to platinum. The competition between parts of the oxidizing agent and other potential ligands in solution is also examined.     

A novel rhenium-aqua structure: the synthesis and structural characterization of (PPh4)4[ReN(H2O)(CN)3-μ-CN-ReN(CN)4]?·?5H2O

A novel cyano bridged rhenium nitrido complex, [ReN(H₂O)(CN)₄-μ-CN-ReN(CN)₄]⁴⁻ (I) was isolated during a kinetic study of the reaction of ReN(H₂O)(CN)₄]²⁻ with pyridine-2,3-dicarboxylic acid. Yellow crystals of (I), suitable for X-ray structure determination were isolated and the structural data showed an unsymmetrical binuclear rhenium complex with a cyano ligand acting as a bridge between two metal atoms, Re(1) and Re(2). The nitrogen of the bridged cyano ligand coordinates trans to the nitrido ligand of Re(1). The rhenium-nitrido bond distances are 1.657(4) and 1.656(5) ? for Re(1)–N(9) and Re(2)–N(10) respectively. Re(1) and Re(2) are displaced from the planes formed by the four carbon atoms of the cyano ligands towards the nitrido ligands by 0.348(2) and 0.3403(2) ?, respectively.     

Syntheses,crystal structures,and properties of two Cd–Fe heterobimetallic compounds with bridging en and dien ligands

From the system Cd(II)–L–[Fe(CN)₆]^4?, complexes [{Cd(en)}₂{Fe(CN)₆}] (1) and [{Cd(H₂O)(dien)}₂{Fe(CN)₆}] ? 4H₂O (2) were prepared and characterized. The same products were also isolated from mother liquors containing [Fe(CN)₆]^3? in which Fe(III) was reduced to Fe(II) upon irradiation. By the combination of IR and Mössbauer spectroscopy, the presence of the low-spin state (S = 0) for Fe(II) was corroborated in both 1 and 2. The Cd(II) and Fe(II) in both complexes are linked by bridging cyano ligands forming a 3-D crystal structure of 1 and a 1-D ribbon-like structural motif in 2. The bidentate en in 1 links two pentacoordinated Cd(II), while in 2 the dien ligand exhibits a rare chelating-bridging bonding mode completing the hexacoordination of Cd(II) and enhancing the dimensionality of the formed structure to 2-D. Fe(II) in both structures exhibits octahedral coordination by cyano bridging in 1 whereas in 2 two cyano ligands are terminal. Water of crystallization and the coordinated water in 2 are involved in hydrogen bonds. Dehydration in 2 is a one-step process with a minimum on the DTA curve at 92°C.     

Chemical conversions of rhodium selenochloride Rh<Subscript>2</Subscript>Se<Subscript>9</Subscript>Cl<Subscript>6</Subscript>

Rhodium selenochloride Rh₂Se₉Cl₆ (1) reacts with aqueous solutions of KCN and CsCl and 4-cyanopyridine (4-CNPy) to give complexes KCs₂Rh(CN)₆ (2) and RhCl₃(4-CNPy)₃ (3). According to X-ray diffraction data, 2 and 3 have mononuclear structures in which the rhodium atoms are in the oxidation state III and six-coordinate environment. Reactions 1 with CN-containing ligands lead to complete displacement of selenium-containing ligands from the rhodium coordination sphere.     

New heterometallic coordination polymers based on zinc(II) complexes with Schiff-base ligands and dicyanometallates: synthesis,crystal structures,and luminescent properties

Four new d¹⁰ heterometallic coordination polymers have been obtained using three Schiff-base ligands, zinc(II) nitrate, and dicyanometallates: ₁^∞[{Zn₃(Salen)₂}{μ-Au(CN)₂}₂] (1); ₁^∞[Zn(Saldmen){μ-Ag(CN)₂}]·2H₂O (2); ₁^∞[Zn(Salampy){μ-Ag(CN)₂}] (3); ₁^∞[Zn(Salampy){μ-Au(CN)₂}] (4). The Schiff bases are obtained from condensation of salicylaldehyde with ethylenediamine (H₂Salen); N,N-dimethyl-ethylenediamine (HSaldmen) and, respectively, 2-aminomethyl-pyridine (HSalampy). The dicyanometallates are K[Ag(CN)₂] and K[Au(CN)₂]. The compounds were characterized by X-ray single-crystal diffraction, infrared spectroscopy, UV–vis spectroscopy, and elemental analysis. In compound 1, the homotrimetallic units, {Zn₃(salen)₂}²⁺, are connected by two [Au(CN)₂]^? bridges, forming a 1-D double chain. In compounds 2–4, the crystal structures show polymeric zigzag chains generated by the mononuclear zinc(II) nodes and [M(CN)₂]^? spacers. The luminescence properties of the new heterometallic polymers have also been investigated.     

Metal Organic Precursors for Yttria

Abstract

Several carboxylic acid derivatives of yttrium that have potential as metal organic deposition (MOD) precursors for yttria were prepared and characterized. These included a traditional MOD precursor bearing 2-ethylhexanoate ligands and a new class of precursors bearing poly-ether carboxylic acid ligands. Notably, the latter complexes are viscous liquids.     

Facile Access to Mono-Cinchona Alkaloid-Derived Ligands

Two facile accesses to mono-cinchona alkaloid-derived ligands, by conventional heating conditions and solvent-free microwave irradiation, are described. 1,4-Dichlorophthalazine (PHAL) or 3,6-dichloropyridazine (PYDZ) reacted with quinine (QN), cinchonine (CN), or cinchonidine (CND) by using CaH₂ as acid-bonding reagent in DMF at 90–100°C to provide mono-cinchona alkaloid-derived ligands 2a–f (87–95%) in 1.5 h. However, the coupling reactions were performed under solvent-free microwave conditions to yield 2a–f (64–89%) within 15 min.     

Formation of Cu<Superscript>I</Superscript>(CH<Subscript>3</Subscript>CN)<Subscript>4</Subscript>ClO<Subscript>4</Subscript> in the reactions of copper(II) perchlorate with acetonitrile in the presence of sulfur-containing organic compounds

Cu(ClO₄)₂·6H₂O was shown to react with 2,2′-[propane-1,3-diylbis(thio-2-phenylnemethylidene]-bis(3-pyridylamine) (I) or (5Z)-2-ethoxycarbonylmethyl-(2-pyridylmethylidene)-3,5-dihydro-4H-imidazol-4-one (II) in the presence of CH₃CN with the reduction of copper(II) to copper(I) and the formation of the tetrahedral complex Cu^I(CH₃CN)₄ClO₄ (III). In the course of the reaction the organic ligands I and II were oxidized to the corresponding sulfoxides.     

Crystal structures of [Hg(<Emphasis Type="Italic">N</Emphasis>-ethylthiourea)<Subscript>2</Subscript>(CN)<Subscript>2</Subscript>] and [Hg(<Emphasis Type="Italic">N</Emphasis>-propylthiourea)<Subscript>2</Subscript>(CN)<Subscript>2</Subscript>]

Two mercury(II) cyanide complexes of N-ethylthiourea (Ettu) and N-propylthiourea (Prtu) ligands, [Hg(Ettu)₂(CN)₂] (1) and [Hg(Prtu)₂(CN)₂] (2), were prepared and their crystal structures were determined by X-ray crystallography. In both structures, the mercury atom is coordinated to two sulfur atoms of thioureas and two cyanide carbon atoms in a pseudo-tetrahedral mode with the bond angles in the range of 90.52(11)–162.2(3)°. The structures are stabilized by N-H—S, N-H—N, and C-H—N intramolecular and intermolecular hydrogen bonds.     

Organotin(IV) azepane dithiocarbamates: Synthesis and characterization of the first organotin(IV) complexes with seven-membered cyclic dithiocarbamates

Abstract

We report the synthesis and spectroscopic characterization of the first organotin(IV) complexes with cyclic seven-membered dithiocarbamate ligands: the azepane-1-carbodithioate and the homopiperazine-1,4-bis-carbodithioate with two different organotin entities, di-n-butyltin and tri-cyclohexyltin: [(C₄H₉)₂Sn{S₂CN(CH₂)₆}₂] (3), [(C₆H₁₁)₃Sn{S₂CN(CH₂)₆}] (4), and [(C₆H₁₁)₃Sn}₂ (μ-S₂CN(C₅H₁₀)NCS₂)] (5). Compounds (3–5) are air-stable both in solid-state and in solution, and were characterized by elemental analyses, IR, FAB⁺–MS, and multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn) spectroscopy. Their molecular structures were unambiguously established by single-crystal X-ray diffraction studies. The geometrical arrangement around the tin atom can be described as distorted octahedral for (3) and distorted trigonal bipyramid for (4) and (5). The coordination mode for both ligands is considered as asymmetric bidentate, as happens in other organotin(IV) dithiocarbamates. Furthermore, (4) and (5) do not exhibit intermolecular secondary interactions, while (3) presents intermolecular interactions between the tin and a sulfur atom with the reciprocally neighboring molecule, giving rise to a zig-zag polymeric structure.     

Dimolybdenum Complex Containing N–H···Mo Interactions. Synthesis and Structure of cis-[Mo2(HDpyF)2(CH3CN)4](BF4)4 and its Transformation to [Mo2(DpyF)2(py)4](BF4)2 [HDpyF?=?Bis(2-pyridyl)formamidine; py?=?pyridine]

The complex cis-[Mo₂(HDpyF)₂(CH₃CN)₄](BF₄)₄, 1, was prepared by the reaction of Mo₂(DpyF)₄ with HBF₄ in CH₃CN, in which new bonding mode of the HDpyF ligand and axial N–H···Mo interactions are observed. Reaction of 1 with pyridine afforded the complex trans-[Mo₂(DpyF)₂(py)₄](BF₄)₂, 2. In complex 1, the neutral bidentate HDpyF ligands bridge the metal centers through one of the amine nitrogen atoms and the adjacent pyridyl nitrogen atom, resulting in the s-trans-anti-s-trans conformation. The anionic DpyF⁻ ligands of 2 adopt the s-trans,s-trans conformation and are coordinated to the Mo centers in bidentate fashions through the two central nitrogen atoms and the two terminal nitrogen atoms are not coordinated. Dedicated to the memory of Professor F. A. Cotton, a great mentor and friend.     

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.

     

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.     

Influence of axial ligands and anions on the Ni–Ni distances in trinickel string complexes: synthesis,structure, and properties of [Ni3(dpa)4(CH3CN)2] · (ClO4)2 · (CH3CN) · H2O

A cation–anion metal string complex with neutral axial ligands, [Ni₃(dpa)₄(CH₃CN)₂] · (ClO₄)₂ · (CH₃CN) · H₂O (1) where dpa^? is 2,2′-dipyridylamine anion, was synthesized and characterized by elemental analysis, IR, fluorescence, UV, and CV spectroscopic methods, and single crystal X-ray analysis. The Ni–Ni distances in 1 are longer than those in [Ni₃(dpa)₄(CH₃CN)₂] · (PF₆)₂ · 3.14CH₃CN (2) and [Ni₃(dpa)₄F₂] · [Ni₃(dpa)₄(H₂O)₂] · (BF₄)₂ · 2CH₃OH, indicating that the counter anions affect the Ni–Ni distances of trinickel string complexes. Compared with Ni₃(dpa)₄Cl₂ and Ni₃(dpa)₄(ClO₄)₂, 1 also has different fluorescence, UV, and CV properties. Therefore, this study clearly indicates that ligands and counter anions largely influence the structures and properties of trinickel string complexes.     

Bis(2-pyridylimino)isoindole (BPI) Ligands with Novel Linker Units: Synthesis and Characterization of Their Palladium and Platinum Complexes

Summary. With the aim of immobilizing bis(2-pyridylimino)isoindolate (BPI) ligands their backbone structure has been functionalized with several linker units. Their fixation was carried out at the stage of the phthalodinitrile precursor by nucleophilic ipso-substitution of 4-nitrophthalodinitrile. Subsequent synthesis of the functionalized phthalodinitriles with two molar equivalents of the 2-aminopyridine derivatives gave the corresponding BPI ligands. Reaction of the ethyleneglycol functionalized BPI derivative with the zeroth generation carbosilane dendrimer [G-0]_4-exo-Cl yielded the functionalized dendrimer [G-0]_4-exo-[O(CH₂)₂O]-10-MeBPI (7). The synthesis of the palladium complexes was carried out by reaction of the protioligands with [(PhCN)₂PdCl₂] in benzene using triethylamine as auxiliary base whereas the first examples of BPI-platinum complexes were prepared using [(COD)PtCl₂] as starting material.     

Structures and fluorescence of two new hetero-dinuclear lanthanide(III) complexes derived from a Schiff-base ligand

Two isostructural dinuclear lanthanide(III)/Schiff-base complexes [{Ce_1.5Eu_0.5(clapi)}₂]·2CH₃CN (1) and [{La_1.5Eu_0.5(clapi)}₂]·2CH₃CN (2) {H₃clapi = 2-(5-chloride-2-hydroxyphenyl)-1,3-bis[4-(5-chloride-2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine} have been prepared by template procedure and characterized by elemental analyses, ICP, IR, and single-crystal X-ray diffraction analyses. Lanthanide ions Ce(III) and Eu(III) in 1, and La(III) and Eu(III) in 2 are disordered with occupancies 0.75 for Ce and 0.25 for Eu in 1; 0.75 for La and 0.25 for Eu in 2. In the compounds, each lanthanide is coordinated to four N and four O atoms from two clapi^3? ligands, forming a distorted square antiprism. Two phenol oxygen atoms from the middle arms of the two heptadentate μ₂-bridging ligands connect the two Ce(Eu) atoms in 1, and La(Eu) in 2. The solution of the two complexes in CH₂Cl₂ exhibits red fluorescence from Eu³⁺ ions at 77 K, very weak at room temperature.