Bis(2,2′‐bipyridyl‐N,N′)­tris­(nitrato‐O,O′)­neodymium

The title compound, [Nd(bipy‐N,N′)₂(NO₃–O,O′)₃], is found to be isomorphous with the La and Lu analogues having three bidentate nitrate and two bipyridyl ligands giving a ten co‐ordinate environment.     

(2,2′‐Bipyridyl‐κ2N,N′)­bis­(salicyl­ato‐κ2O,O′)­zinc(II)

The asymmetric unit of the title compound, [Zn(C₇H₅O₃)₂(C₁₀H₈N₂)], contains one monomeric zinc complex. The Zn atom is coordinated to one 2,2′‐bipyridyl ligand via both N atoms and to two salicyl­ate anions (Hsal⁻) in a bidentate chelating manner involving carboxyl­ate O‐atom coordination. The complex exhibits a distorted octahedral geometry about the Zn^II atom, with the `apical' positions occupied by one of the two N atoms of the bipyridyl ligand and an O atom from one Hsal<sup>−</sup> ligand; the Zn atom is 0.168 (1) Å out of the `basal' plane. Two intramolecular six‐membered hydrogen‐bonded rings are present, generated from interactions between the carboxyl and hydroxyl groups of the salicyl­ate ligands. The crystal packing is governed by weak C—H⋯O and C—H⋯π interactions.     

Aqua­(5,6‐di­methyl‐1,10‐phenanthroline‐N,N′)­(glycolato‐O,O′)­copper(II) nitrate

The title compound, [Cu(C₂H₃O₃)(C₁₄H₁₂N₂)(H₂O)]NO₃, is the first example of a mixed copper glycolate compound with a di­imine ligand. The copper(II) compound lies in a slightly distorted square‐pyramidal coordination environment with one water mol­ecule coordinated in the apical position. The glycolate ligand binds to the Cu atom as a chelate through a carboxyl­ate and the α‐OH O atom which, together with the N atoms of the substituted phenanthroline, constitute the base of the pyramid.     

Neutral Pentacoordinate Silicon(IV) Complexes with a Tridentate Dianionic O,N,O or N,N,O Ligand,an Anionic PhX Ligand (X = O,S, Se), and a Phenyl Group: Synthesis and Structural Characterization in the Solid State and in Solution

A series of neutral pentacoordinate silicon(IV) complexes with a SiO₃NC, SiO₂SNC, SiO₂SeNC, SiO₂N₂C, SiOSN₂C, or SiOSeN₂C skeleton was synthesized and structurally characterized by multinuclear NMR spectroscopy in the solid state and in solution and by single‐crystal X‐ray diffraction. The compounds studied contain a tridentate dianionic O,N,O or N,N,O ligand, an anionic PhX ligand (X = O, S, Se), and a phenyl group. The structures, NMR spectroscopic parameters, and chemical properties of these silicon(IV) complexes were compared with those of related compounds that contain a tridentate dianionic S,N,O ligand instead of the O,N,O or N,N,O ligand.     

N‐(4‐Methoxy­benzyl­idene)‐N′‐(2‐pyridyl)­hydrazine

Molecules of the title compound (alternative name p‐methoxybenzaldehyde 2‐pyridyl­hydrazone), C₁₃H₁₃N₃O, adopt an E configuration about the azomethine C=N double bond. Molecules are almost planar, the dihedral angle between the pyridine and methoxy­phenyl rings being only 6.19 (12)°. Pairwise N—H⃛N hydrogen bonds [R(8) in graph‐set notation] link centrosymmetrically related mol­ecules into discrete pairs.     

{2‐[(3‐Amino­propyl)­amino­propyl­imino­methyl]­imidazol­ato‐N,N′,N′′,N′′′}­(methanol‐O)­copper(II) per­chlorate

In the title compound, [Cu(C₁₀H₁₈N₅)(CH₄O)]ClO₄, four N atoms from the deprotonated ligand derived from bis(3‐amino­propyl)­amine and 2‐imidazole­carbox­aldehyde are coordinated to the Cu atom. The four N atoms occupy equatorial positions with Cu—N bond distances ranging from 1.998 (2) to 2.046 (3) Å. The methanol O atom occupies one axial position with a Cu—O bond distance of 2.295 (2) Å.     

Syntheses and Structures of Nitridorhenium(V) and Nitridotechnetium(V) Complexes with N,N‐[(Dialkylamino)(thiocarbonyl)]‐N′‐(2‐hydroxyphenyl)benzamidines

[MNCl₂(PPh₃)₂] complexes (M = Re, Tc) react with N‐[(dialkylamino)(thiocarbonyl)]‐N′‐(2‐hydroxyphenyl)benzamidines (H₂L¹) with formation of neutral, five‐coordinate nitrido complexes of the composition [MN(L¹)(PPh₃)]. The products have distorted square‐pyramidal coordination spheres with each a tridentate, double‐deprotonated benzamidine and a PPh₃ ligand in their basal planes.     

Tris(2,2′‐bipyridyl‐N,N′)­iron(II) diperchlorate

The title compound, [Fe(C₁₀H₈N₂)₃](ClO₄)₂, is isomorphous with the Zn^II and Ru^II analogues. A twofold axis passes through the metal atom and the midpoint of the C—C bond joining the two pyridine rings of one of the bi­pyridyl ligands.     

Polymer Complexes: supramolecular assemblies and structures of poly[N‐(2′‐pyridyl)propenamide] complexes

A number of new polymer complexes of palladium(II), platinum(II) and copper(II) containing homopolymer (N‐(2′‐pyridyl)propenamide; APH) and various anions (Cl^?, Br^?, I^? or NO₃^?) have been synthesized and characterized by elemental analyses, magnetic susceptibility, electron paramagnetic resonance, IR and reflectance spectral measurements. The homopolymer shows three types of coordination behavior. In the mononuclear polymer complexes 1–6 and 9 it acts as a neutral bidentate ligand chelated through the pyridine‐nitrogen and amide‐oxygen atoms, whereas in the square‐planar [Pd(APH)₂X₂] (X = Cl, Br) unidentate APH is coordinated through the pyridine‐nitrogen atom alone. Under alkaline conditions APH is deprotonated in the presence of palladium(II) to form [Pd(AP)₂] ( 10 ), AP being an anionic bidentate ligand and chelating through the pyridine‐nitrogen and amide‐oxygen atoms. The poly‐chelates are of 1:1 and 1:3 (metal:homopolymer) stoichiometry and exhibit six‐coordination. The polymer complexes of stoichiometric [(APH)₂CuX₂] contain square planar (APH)₂ Cu²⁺ units and the anions X^? are in the axial positions, giving distorted octahedral configurations. From the electron paramagnetic resonance and spectral data, the orbital reduction factors were calculated. Copyright © 2004 John Wiley & Sons, Ltd.     

Tris(2,2′‐bioxazoline‐κ2N,N′)copper(II) diperchlorate and tris(2,2′‐bioxazoline‐κ2N,N′)­nickel(II) diperchlorate

In the two isomorphous title compounds, viz. tris­[2,2′‐bi(4,5‐di­hydro‐1,3‐oxazole)‐κ²N,N′]copper(II) diperchlorate, [Cu(C₆H₈N₂O₂)₃](ClO₄)₂, (I), and tris­[2,2′‐bi(4,5‐di­hydro‐1,3‐oxazole)‐κ²N,N′]­nickel(II) diperchlorate, [Ni(C₆H₈N₂O₂)₃](ClO₄)₂, (II), the M^II ions each have a distorted octahedral coordination geometry formed via six N atoms from three 2,2′‐bioxazoline ligands. For each ligand, the two five‐membered rings are nearly coplanar. It is noteworthy that the Jahn–Teller effect is stronger in (I) than in (II). The three‐dimensional supramolecular structures of (I) and (II) are formed via weak hydrogen‐bonding interactions between O atoms from per­chlorate anions and H atoms from 2,2′‐bioxazoline ligands.     

catena‐Poly­[[[bis­(perchlorato‐O)­(1,10‐phenanthroline‐N,N′)­copper(II)]‐μ‐4,4′‐bi­pyridine‐N:N′] monohydrate]

The Cu atom in the title complex {[Cu(C₁₀H₈N₂)(C₁₂H₈N₂)(ClO₄)₂]·H₂O}_n, has an N₄O₂ octahedral coordination geometry, the Cu atoms being bridged by the bi­pyridine and chelated by the phenanthroline heterocycles. Adjacent mol­ecules are linked into a zigzag chain running along the c axis of the monoclinic unit cell. The chains are connected through lattice water mol­ecules to produce a layer structure.     

Tris(2,2′‐bipyridyl‐N,N′)­nickel(II) thio­sulfate heptahydrate

The structure of the title compound, [Ni(C₁₀H₈­N₂)₃](S₂O₃)·7H₂O, consists of monomeric Ni(bipy)₃²⁺ cations embedded in an anionic network made up of S₂O₃^2? ions and hydration water mol­ecules. The structure presents the unusual feature of two neighbouring thio­sulfates approaching linearly head‐to‐head with an unusually short S?S contact distance of 3.25 Å.     

Semisynthesis of 3′(2′)‐O‐(Aminoacyl)‐tRNA Derivatives as Ribosomal Substrate

An efficient synthesis of (3′‐terminally) 3′(2′)‐O‐aminoacylated pCpA derivatives is described, which could lead to the production of (aminoacyl)‐tRNAs following T4 RNA ligase mediated ligation. The tetrahydrofuranyl (thf) group was used as a permanent protective group for the 2′‐OH of the cytidine moiety which can be removed during the purification of the 3′(2′)‐O‐aminoacylated‐pCpA. This approach allowed for a general synthesis of (3′‐terminally) 3′(2′)‐O‐aminoacylated oligonucleotides. The fully protected pCpA 14 was synthesized by phosphoramidite chemistry and treated with NH₃ solution to remove the 2‐cyanoethyl and benzoyl groups (→ 15 ; Schemes 1 and 2). The 2′‐O‐thf‐protected‐pCpA 15 was coupled with α‐amino acid cyanomethyl esters, and the products 20a – c were deprotected and purified with AcOH buffer to afford 3′(2′)‐O‐aminoacylated pCpA 21a – c in high yields. The 3′(2′)‐O‐aminoacylated pCpA were efficiently ligated with tRNA(? CA) to yield (aminoacyl)‐tRNA which was an active substrate for the ribosome.     

Copper(II) and Cadmium(II) Complexes Based on N,N‐Bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine Ligand: Syntheses,Structures, Magnetic,and Luminescent Properties

The reaction of the aryl‐oxide ligand H₂L [H₂L = N,N‐bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine] with CuSO₄ · 5H₂O, CuCl₂ · 2H₂O, CuBr₂, CdCl₂ · 2.5H₂O, and Cd(OAc)₂ · 2H₂O, respectively, under hydrothermal conditions gave the complexes [Cu(H₂L¹)₂] · SO₄ · 3CH₃OH ( 1 ), [Cu₂(H₂L²)₂Cl₄] ( 2 ), [Cu₂(H₂L²)₂Br₄] ( 3 ), [Cd₂(HL)₂Cl₂] ( 4 ), and [Cd₂(L)₂(CH₃COOH)₂] · H₂L ( 5 ), where H₂L¹ [H₂L¹ = 2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenol] and H₂L² [H₂L² = 2‐(2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenoxy)‐4, 6‐dimethylphenol] were derived from the solvothermal in situ metal/ligand reactions. These complexes were characterized by IR spectroscopy, elementary analysis, and X‐ray diffraction. A low‐temperature magnetic susceptibility measurement for the solid sample of 2 revealed antiferromagnetic interactions between two central copper(II) atoms. The emission property studies for complexes 4 and 5 indicated strong luminescence emission.     

Di­bromo(N,N′‐di‐2‐pyridyl­amine‐κ2N,N′)­palladium(II)

The palladium center of the title compound, [PdBr₂(C₁₀H₉N₃)], has a slightly distorted square‐planar conformation, with the Pd atom bonded to the two pyridine N atoms of the di‐2‐pyridyl­amine moiety and to two Br atoms. The Pd—Br and Pd—N bond lengths are 2.4168 (6)/2.4201 (5) and 2.036 (3)/2.042 (3) Å, respectively.     

Synthesis and Structural Characterization of Cationic Complexes with Hexacoordinate Silicon(IV) and Three Bidentate 1‐Oxopyridine‐2‐olato(1–) Ligands

The cationic complexes with hexacoordinate silicon(IV), tris[1‐oxopyridine‐2‐olato(1–)]silicon(IV) trifluoromethanesulfonate ( 4 ), 4 · ¹/₂ C₅H₅NO₂, tris[1‐oxopyridine‐2‐olato(1–)]silicon(IV) ethyl sulfate–ethanol ( 5 · EtOH), and tris[1‐oxopyridine‐2‐olato(1–)]silicon(IV) isopropyl sulfate ( 6 ), were synthesized. The identities of 4 , 4 · ¹/₂ C₅H₅NO₂, 5 · EtOH, and 6 were established by elemental analyses (C, H, N, S), mass‐spectrometric studies (FAB MS) as well as solid‐state (²⁹Si) and solution (¹H, ¹³C, ¹⁹F, ²⁹Si) NMR experiments. In addition, 4 · ¹/₂ C₅H₅NO₂ was structurally characterized by single‐crystal X‐ray diffraction.     

N,N′‐Bis­[1‐(pyrazin‐2‐yl)­ethyl­idene]­hydrazine

Molecules of the title compound, C₁₂H₁₂N₆, contain both a di­imine linkage and an N—N bond, and assume a planar structure. The compound lies about an inversion centre and there are three intramolecular C—H⋯N hydrogen bonds.     

Synthesis and Reactivity of Phenylimidorhenium(V) Complexes with N‐[(N′,N′‐Dialkylamino)(thiocarbonyl)]benzamidines. Observation of a pH‐Dependent Isomerisation of Related Oxorhenium(V) Compounds

Reactions of [Re(NPh)Cl₃(PPh₃)₂] with N‐[(N′,N′‐dialkylamino)(thiocarbonyl)]benzamidines (H₂R₂tcb) (R₂ = Et₂, (CH₂)₂O(CH₂)₂) in methanol give mono‐chelates of the composition [Re(NPh)Cl₂(PPh₃)(HR₂tcb)] as the sole products independent of the amount of the added H₂R₂tcb. Addition of a supporting base such as NEt₃ results in hydrolysis of the Re=NPh bonds and partial hydrolysis of the thiocarbamoylbenzamidines. Orange‐brown, cationic oxorhenium(V) compounds of the formula [ReO(HR₂tcb)₂]Cl were isolated from such reaction mixtures in good yields, and the formation of small amount of the unusual sulfido/persulfido‐bridged Re^V dimer [{ReO(HEt₂tcb)}₂(μ‐S)(μ‐S₂)] give evidence for a considerable degree of ligand decomposition under such conditions. The products have been characterized by spectroscopic methods and X‐ray crystallography. Acidification of orange‐brown solutions of the five‐coordinate Re^V oxo complex [ReO(HEt₂tcb)₂]Cl causes an immediate change of the color and deep blue crystals of the neutral, six‐coordinate [ReOCl(HEt₂tcb)₂] can be isolated from the resulting mixture. Alternatively, the product can be prepared by a ligand‐exchange protocol starting from (NBu₄)[ReOCl₄] and H₂Et₂tcb. The pH‐dependent isomerization between [ReO(HEt₂tcb)₂]Cl and [ReOCl(HEt₂tcb)₂] is reversible.     

μ‐{N,N′‐Bis[2‐(dimethyl­amino)ethyl]oxamidato(2–)}‐1κ2O,O′:2κ4N,N′,N′′,N′′′‐bis­(4,4′‐dimethyl‐2,2′‐bipyridine‐1κ2N,N′)dinickel(II) bis­(perchlorate)

In the crystal structure of the title complex, [Ni₂(C₁₀H₂₀N₄O₂)(C₁₂H₁₂N₂)₂](ClO₄)₂ or [Ni(dmaeoxd)Ni(dmbp)₂](ClO₄)₂ {H₂dmaeoxd is N,N′‐bis­[2‐(dimethyl­amino)ethyl]oxamide and dmbp is 4,4′‐dimethyl‐2,2′‐bipyridine}, the deprotonated dmaeoxd²⁻ ligand is in a cis conformation and bridges two Ni^II atoms, one of which is located in a slightly distorted square‐planar environment, while the other is in an irregular octa­hedral environment. The cation is located on a twofold symmetry axis running through both Ni atoms. The dmaeoxd²⁻ ligands inter­act with each other via C—H⋯O hydrogen bonds and π–π inter­actions, which results in an extended chain along the c axis.     

Di­aqua­bis(1,10‐phenanthroline‐κ2N,N′)­manganese(II) thiodiglycolate bis(1,10‐phenanthroline‐κ2N,N′)(thiodiglycolato‐κ2O,O′)­manganese(II) tridecahydrate

The title compound, [Mn(C₁₂H₈N₂)₂(H₂O)₂](C₄H₄O₄S)·[Mn(C₄H₄O₄S)(C₁₂H₈N₂)₂]·13H₂O, contains one dianion of thio­diglycolic acid (tdga²⁻) and two independent man­ganese(II) moieties, viz. [Mn(phen)₂(H₂O)₂]²⁺ and [Mn(tdga)(phen)₂], where phen is 1,10‐phenanthroline. The Mn^II atoms are octahedrally coordinated by four N atoms of two bidentate phen ligands [Mn—N = 2.240 (2)–2.3222 (19) Å] and either two water O atoms or two tdga carboxyl O atoms [Mn—O = 2.1214 (17)–2.1512 (17) Å]. The tdga ligand chelates as an O,O′‐bidentate ligand, forming an eight‐membered ring with one Mn atom. The free tdga²⁻ dianion is hydrogen bonded to an [Mn(phen)₂(H₂O)₂]²⁺ ion, with O⋯O distances of 2.606 (2) and 2.649 (2) Å. The crystal structure is further stabilized by an extensive network of hydrogen bonds involving 13 water mol­ecules.