N,N′,N′′,N′′′‐Tetraethylterephthalamidinium bis(tetrazolate)

The crystal structure of the title 2:1 salt of tetrazole and a substituted terephthal­amidine, C₁₆H₂₈N₄²⁺·2CHN₄^?, contains an infinite network of hydrogen bonds, with short N?N distances of 2.820 (2) and 2.8585 (19) Å between the tetrazolate anion and the amidinium cation. Involvement of the lateral N atoms of the tetrazole in the hydrogen bonding appears to be a typical binding pattern for the tetrazolate anion.     

Two new thiophosphoramide structures: N,N′,N′′‐tricyclohexylphosphorothioic triamide and O,O′‐diethyl (2‐phenylhydrazin‐1‐yl)thiophosphonate

The compound N,N′,N′′‐tricyclohexylphosphorothioic triamide, C₁₈H₃₆N₃PS or P(S)[NHC₆H₁₁]₃, (I), crystallizes in the space group Pnma with the molecule lying across a mirror plane; one N atom lies on the mirror plane, whereas the bond‐angle sum at the other N atom has a deviation of some 8° from the ideal value of 360° for a planar configuration. The orientation of the atoms attached to this nonplanar N atom corresponds to an anti orientation of the corresponding lone electron pair (LEP) with respect to the P=S group. The P=S bond length of 1.9785 (6) Å is within the expected range for compounds with a P(S)[N]₃ skeleton; however, it is in the region of the longest bond lengths found for analogous structures. This may be due to the involvement of the P=S group in N—H...S=P hydrogen bonds. In O,O′‐diethyl (2‐phenylhydrazin‐1‐yl)thiophosphonate, C₁₀H₁₇N₂O₂PS or P(S)[OC₂H₅]₂[NHNHC₆H₅], (II), the bond‐angle sum at the N atom attached to the phenyl ring is 345.1°, whereas, for the N atom bonded to the P atom, a practically planar environment is observed, with a bond‐angle sum of 359.1°. A Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B 58 , 380–388] analysis shows a shift of the maximum population of P=S bond lengths in compounds with a P(S)[O]₂[N] skeleton to the shorter bond lengths relative to compounds with a P(S)[N]₃ skeleton. The influence of this difference on the collective tendencies of N...S distances in N—H...S hydrogen bonds for structures with P(S)[N]₃ and P(S)[O]₂[N] segments were studied through a CSD analysis.     

Synthesis,spectroscopic characterization (IR, 1H, 13C and 119Sn NMR,electrospray mass spectrometry) and toxicity of new organotin(IV) complexes with N,N′,O‐ and N,N′,S‐scorpionate ligands

New organotin(IV) derivatives containing the anionic ligands bis(3,5‐dimethylpyrazol‐1‐yl)dithioacetate [LCS₂]⁻ and bis(3,5‐dimethylpyrazol‐1‐yl)acetate [LCO₂]⁻ have been synthesized from reaction between (CH₃)₂SnCl₂ and lithium salts of the ligands. Mononuclear complexes of the type {[LCX₂](CH₃)₂SnCl} (X = S or O) have been obtained and fully characterized by elemental analyses and FT‐IR in the solid state and by NMR (¹H, ¹³C and ¹¹⁹Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry in solution. The acute toxicity of new organotin(IV) derivatives on rat was studied, comparing their effect with those of dimethyltin chloride (CH₃)₂SnCl₂. The comparison of LD₅₀ of organotin(IV) complexes and (CH₃)₂SnCl₂ administered intraperitoneally, as a single dose, evaluated in vivo on rats, showed that toxicity decreases as follows: (CH₃)₂SnCl₂ > LCO₂ > LCS₂. The effect of these organotin(IV) complexes on DNA was evaluated in vitro and in vivo on rats treated with different doses of these compounds (1/20 LD₅₀ and 1/100 LD₅₀). The lymphocyte DNA status was assessed by the comet assay, a rapid and sensitive single‐cell electrophoresis technique, used to detect primary DNA damage in individual cells. After 36 h from the start of treatment the two new organotin(IV) derivatives induced a significant rise in comet assay parameters, indicating an increasing presence of damaged DNA. Copyright © 2005 John Wiley & Sons, Ltd.     

(12‐Hydro­xy­methyl‐5,5,7,12,14‐penta­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane‐N‐acetato‐N,N′,N′′,N′′′,O,O′)cobalt(III) chloride perchlorate monohydrate

In the title compound, [Co(C₁₈H₃₇N₄O₃)](ClO₄)Cl·H₂O, the Co^III ion has a distorted octahedral geometry, with four N atoms and two O atoms constituting the coordination sphere. The crystal structure is stabilized by a three‐dimensional network of hydrogen bonds.     

Bis[(dihydrogen pyrophosphato‐κ2O,O′)(2,2′:6′,2′′‐terpyridine‐κ3N,N′,N′′)copper(II)] 4.5‐hydrate

The title copper complex, [Cu(H₂P₂O₇)(C₁₅H₁₁N₃)]₂·4.5H₂O, consists of two very similar independent Cu(Tpy)H₂P₂O₇ monomeric units (Tpy is 2,2′:6′,2′′‐terpyridine) plus four and a half water molecules of hydration, some of which are disordered. Tpy units bind through the usual triple bite via their N atoms, and the H₂P₂O₇²⁻ anions coordinate through two O atoms from two different phosphate units. Each independent CuN₃O₂ chromophore can be described as a slightly deformed square pyramid, with one of them having a sixth, semicoordinated, O atom from a centrosymmetrically related CuN₃O₂ unit in a weakly bound second apical position suggesting an octahedral environment for the cation and weak dimerization of the molecule. The two independent complex molecules are connected via two strong O—H...O interactions between the phosphate groups to form hydrogen‐bonded dinuclear units, further linked into [111] columns, resulting in a very complex three‐dimensional supramolecular structure through a variety of classical and nonclassical hydrogen bonds, as well as π–π interactions.     

Phenol Based‐Ligands with Two Adjacent N,N′,O‐Binding Pockets

The synthesis of three new ligands and their coordination behavior towards zinc ions with strongly coordinating anions and cobalt ions with weakly coordinating anions are reported. The ligands have two adjacent imidazolyl‐pyridinyl and pyrazolyl‐pyridinyl binding pockets, respectively, which are linked by a phenol unit. We also investigated the dynamic behavior of the ligand having the imidazolyl‐pyridiyl sidearm in solution. The reaction of the ligands and ZnCl₂ yielded complexes of the type [ L Zn₂Cl₃]. When we used Co^II salts with weakly coordinating anions, complexes of the general formula [ L ₂Co₂]²⁺ were formed.     

A new synthesis of 2′,3′-dideoxycytidine

A new synthesis of 2′,3′-dideoxycytidine is described and the utility of this synthesis to prepare larger quantities of said nucleoside is shown.     

{μ‐N,N′‐Bis[2‐(dimethylamino)ethyl]oxamidato(2–)‐κ6N,N′,O′:N′′,N′′′,O}bis[(2,2′‐bipyridine‐κ2N,N′)copper(II)] bis(perchlorate)

In the crystal structure of the title complex, [Cu₂(C₁₀H₂₀N₄O₂)(C₁₀H₈N₂)₂](ClO₄)₂, the deprotonated dmaeoxd²⁻ ligand {H₂dmaeoxd is N,N′‐bis[2‐(dimethylamino)ethyl]oxamide} occupies an inversion centre at the mid‐point of the central C—C bond and is thus in a trans conformation. The two Cu^II atoms are located in slightly distorted square‐based pyramidal environments. The binuclear units interact with each other viaπ–π interactions to form a one‐dimensional chain extending in the c direction.     

Synthese,Struktur und einige Reaktionen [N-(N′,N′,N″,N″-tetramethyl)-guanidinyl]-substituierter Phosphorylverbindungen

Synthesis, Structure, and some Reactions of N-(N′,N′,N″,N″-tetramethyl)guanidinyl-substituted Phosphoryl Compounds The tetramethylguanidinyl-substituted phosphoryl compounds 1 – 10 were prepared in the reaction of the appropriate chlorophosphoryl compounds with either N′,N′,N″,N″-tetramethylguanidine (HTMG) or N-trimethylsilyl-(N′,N′,N″,N″-tetramethyl)guanidine (TMSTMG). With methyl iodide 1 reacted with N-alkylation to give the ammonium salt 11. 1 reacted with BF₃ · Et₂O at both imino nitrogen atoms with formation of the bis-BF₃-adduct 12 . The X-ray structure determination of phenylphosphonic acid-bis(N′,N′,N″,N″-tetramethylguanidinide) 3 shows shortened PN-bonds and widened PNC-angles, consistent with the partial double bond character of the PN-bond.     

A new polymorph of poly[bis(μ2‐perchlorato‐κ2O:O′)(2,2′:6′,2′′‐terpyridine‐κ3N,N′,N′′)lead(II)] with a greatly extended chain repeat distance

In the title compound, [Pb(ClO₄)₂(C₁₅H₁₁N₃)]_n, two molecules occupy general positions while the third lies on a crystallographic twofold axis, giving a total of two and a half molecules per asymmetric unit. Each metal centre is coordinated equatorially by three 2,2′:6′,2′′‐terpyridine (terpy) N‐donor atoms and axially by two perchlorate O‐donor atoms. The distorted pentagonal bipyramidal geometry is completed by two equatorial O‐donor atoms from two perchlorate anions which bridge to two different adjacent metal centres. The coordination about each metal centre is very similar to that seen at the unique Pb^II centre in the previously published polymorph [Engelhardt, Harrowfield, Miyamae, Patrick, Skelton, Soudi & White (1996). Aust. J. Chem. 49 , 1135–1146], but the new polymorph differs from it by the insertion on each side of an existing [bis(perchlorato)(terpy)lead(II)] molecule of two additional such units. Pairs of asymmetrically bridging perchlorate anions link irregularly spaced Pb^II centres into undulating chains parallel to [201] which exhibit a repeat distance of 26.280 (4) Å. The significance of this new polymorph lies in the fact that, while it is chemically identical to the known polymorph, it is structurally distinct from it.     

Unusual mass spectrometric fragmentation of N,N′-diethyl-N,N′-diphenylurea

The electron impact mass spectrum of N,N′-diethyl-N,N′-diphenylurea contains the ion m/z 164 which is of low abundance at normal energy of ionizing electrons but prominent at 15-20eV. The mechanism of its formation has been revealed by means of labelled compounds. It is rationalized in terms of an unusual formation of styrene lost as a neutral molecule.     

Hexaamminecobalt(III) aquabis(nitrilotriacetato‐κ4N,O,O′,O′′)gadolinate(III) octahydrate

Crystals of the title compound, [Co(NH₃)₆][Gd(C₆H₆NO₆)₂(H₂O)]·8H₂O, were synthesized in and collected from aqueous solution. The hexaamminecobalt(III) cation has the expected octahedral geometry, while the Gd coordination sphere has the geometry of a tricapped trigonal prism, with the two nitrilo­tri­acetate N atoms and one water mol­ecule occupying the capping positions.     

N,N,N′,N′‐Tetraalkylaminoazoxybenzene Derivatives; Convenient Synthesis and Mechanistic Study

N,N,N′,N′‐tetraalkyaminoazoxybenzene derivatives were conveniently prepared by the coupling of N,N‐dialkylnitrosoaniline in the presence of acetone and KOH. The reaction mechanism was proposed and investigated, and the structure of compound 3b was also confirmed by single crystal X‐ray diffractometry.     

Poly[(N,N‐dimethylformamide‐κO)(μ3‐4,4′‐ethylenedibenzoato‐κ5O,O′:O′:O′′,O′′′)(pyrazino[2,3‐f][1,10]phenanthroline‐κ2N8,N9)lead(II)]

In the title Pb^II coordination polymer, [Pb(C₁₆H₁₀O₄)(C₁₄H₈N₄)(C₃H₇NO)]_n, each Pb^II atom is eight‐coordinated by two chelating N atoms from one pyrazino[2,3‐f][1,10]phenanthroline (L) ligand, one dimethylformamide (DMF) O atom and five carboxylate O atoms from three different 4,4′‐ethylenedibenzoate (eedb) ligands. The eedb dianions bridge neighbouring Pb^II centres through four typical Pb—O bonds and one longer Pb—O interaction to form a two‐dimensional structure. The C atoms from the L and eedb ligands form C—H...O hydrogen bonds with the O atoms of eedb and DMF ligands, which further stabilize the structure. The title compound is the first Pb^II coordination polymer incorporating the L ligand.