Volume 55, Issue 7

N-Trimethylsilyl-1 -methylphospholane imine has been prepared by the Staudinger reaction of 1-methylphospholane with trimethylsilyl azide. Transsilylation reactions of the phosphine imine with dichloro or dibromodimethylsilane lead to dimeric N-(halogenodimethylsilyl)-l-methylphospholane imines with an ionic type of structure, containing a dicationic four-membered Si-N ring system. Upon heating, the chloro compound undergoes a reversible isomerization to give the corresponding covalent monomer.

[Cu 2 (L)(O 2 CMe)] · H 2 O (L = 1,3-Bis(2-Hydroxy-1-napthylideneamino)propan-2-ol) was synthesized and its crystal structure determined. (C 27 H 23 N 2 O 5 Cu 2 ).H 2 O , monoclinic, space group P2 1 /c, a = 11.795(3), b = 17.988(5), c = 12.005(6) Å, β = 109.99(3)°, V = 2393(2) Å 3 , Z = 4. Two copper(II) ions in a square-planar coordination are bridged by alkoxide and acetate oxygen atoms to form a dinuclear unit. The metal coordination sphere is four-coordinate, planar with an NO 3 donor set. The dihedral angle between the two coordination planes is 6.34(9)°. The copper(II) centers are separated by 3.492(2) Å and weakly antiferromagnetically coupled (-2J = 163.6 cm -1 ), which follows from temperature-dependent magnetic susceptibility measurements in the temperature range 4.6 to 310 K. The Cu-O-Cu angle is 133.5(1)° in the super-exchange pathway. The weak antiferromagnetic coupling of the complex is interpreted in terms of countercomplementary effects of the different bridging ligands which participate in the super-exchange interaction. The magnetic moment at 310 K is ca. 2.7 B. M., but 0.2 B. M. at 4.6 K. The magnetic susceptibility is at a maximum near 140 K and decreases rapidly as the temperature is lowered to liquid helium temperature.

The syntheses of different nitroxide radicals are reported. The thermal behaviour of the ni­ troxide radicals was examined by polarizing microscopy, differential scanning calorimetry as well as X-ray diffraction experiments. Temperature dependent magnetic susceptibility mea­surements were carried out in order to determine the magnetic properties of these nitroxide radicals. The majority of the radicals presented here show weak antiferromagnetic exchange interactions.

The coordination compounds of the general formula Ln(HL) 2 (NO 3 ) 3 , (where Ln = La - Eu (without Pm), HL = C 6 H 5 C(O)NHP(O)[N(CH 3 ) 2 ] 2 , N,Nʹ-tetramethyl-Nʺ-benzovlphosphoryl-triamide) have been synthesized and characterized by means of IR, UV-VIS, 1 H, 31 P NMR spectroscopy, and X-ray analysis. The complexes are isostructural according to X-ray powder diffraction studies. The crystal structure of the cerium(lll) complex has been determined. Crystal data: monoclinic, P2 1 /c, with a = 10.503(9), b = 15.62(2), c = 21.91(2) Å, β = 99.56(8)°, Z = 4, V = 3546(6) Å 3 , R1= 0.0550, wR2 = 0.1383 for 6970 unique reflections used. The complex has a molecular structure. Neutral phosphoryltriamide ligands are coordinated to the metal ion in a bidentate manner via phosphoryl and carbonyl oxygen atoms with formation of six membered chelate rings. The coordination polyhedron of the Ce atom is a sphenocorona; C.N. = 10 (4 O[HL] + 6 O [NO 3 - ]).

The Grignard reagent obtained from 2-(6-bromohexyloxy)-tetrahydropyrane, by treatment with anhydrous manganese(II) chloride was transformed to the corresponding organomanganese reagent, which was coupled with E-1-bromo-3-hexeneby treatment with anhydrous manganese chloride. Further deprotection and acetylation furnished E-9-dodecen-1-yl acetate. A second procedure involved the coupling of E-3-hexenylmanganese bromide and 6-bromohexyl acetate. Coupling reactions were carried out at 0 °C, using tetrahydrofurane and N-methylpyrrolidone as co-solvent.

The coordination chemistry of 2,2′-dipyridyldiselenide (PySeSePy) towards mangane­se, copper and zinc centres has been studied. The complexes [MnBr 2 -N,N′-(PySeSePy)] (1), [CuBr 2 -N,N′-(PySeSePy)] (2), [Cu-(μ-Br)-N,N′-(PySeSePy)] 2 (3), [Cu-(μ-Br)-{μ-N,N′-(PySeSePy)}] n (4), [Cu-(μ-Cl)-N,N′-(PySeSePy)] 2 (5), [Zn(OOCC 6 F 5 ) 2 -N,N′-(PySeSePy)] (6) and [Zn (OSO 2 CF 3 ) 2 -N,N′-(PySeSePy)] (7) have been synthesised and the crystal structures of 1, 3, 4 and 6 determined. 1, 3 and 6 display seven-membered metallacycles with tetrahedral coordination of the metal centres. In these cases 2,2′-dipyridyldiselenide acts as a chelating ligand. In the polymeric complex 4, 2,2′-dipyridyldiselenide acts as a bridging ligand. All com­ plexes display selenium-selenium single bonds with an average length of 232 pm. In contrast to the analogous chloro and nitrato complexes, the zinc complexes 6 and 7 are not dissociated in solution, as evidenced by 77 Se NMR experiments. The corresponding resonances are shifted downfield in comparison with the ligand.

The dark red tetrahydrotetrathiafulvalenium radical cation has been generated 20 years ago by iodine oxidation of hexathia-dispiro[4.0.4.4]decane and characterized in solution by its temperature-dependent ESR spectrum. Here we report the single crystal growth of its tetrachloroaluminate salt as well as its low temperature structure determination, which proves the C=C double bond to be elongated to 140 pm length and one molecular half to be twisted by 7°. The assumed slight cyanine type distortion is supported by structural comparison with tetrakis(dimethylamino)ethene dication salts and with the 1:3 complex of tetrahydrotetrathiafulvalene mercury dichloride. Unrestricted Density Functional Theory calculations predict both the spin as well as the positive charge to be distributed predominantly within the π molecular center {S 2 C=CS 2 }.

The phase relations in the quaternary system Bi/Se/O/Cl have been studied and the existence of several new compounds in the pseudotemary area Bi 2 O 3 /Bi 2 Se 3 /BiCl 3 has been established by solid state and chemical vapour transport reactions. The phase diagram is derived from X-ray powder diffraction and thermal analysisdata, and from measurements of the decomposition pressure behaviour. Three new quaternary phases with different compositions exist in the system: Bi 4 O 4 SeCl 2 , Bi 10 O 12 SeCl 4 and Bi 22 O 28 SeCl 8 . By estimation of the thermodynamic data of the quaternary phases it is possible to calculate complex heterogeneous chemical equilibria between all the binary, ternary and quaternary compounds of the phase diagram. As a result, we can describe thermodynamically the observed phase relations and the direction of thermal decomposition of the respective compounds.

Five phases exist in the system Fe-Si: Fe 3 Si, Fe 2 Si, Fe 5 Si 3 , FeSi, α-and β-FeSi 2 . All phases could be prepared by chemical transport with iodine as transport agent in the temperature range between T 1 (700 °C) and T 2 (1030 °C). In a attempted systematic clarification of the chemical transport reactions of all phases in the system, the effective transport equilibria were determined. Thermodynamic calculations show satisfactory agreement between calcula­tion and experiment.

Pseudoternary System Bi 2 O 3 /Bi 2 Se 3 /Bi 2 Te 3 , Phase Diagram, Thermodynamic Data The phase diagram of the pseudoternary system Bi 2 O 3 /Bi 2 Se 3 /Bi 2 Te 3 is found to include a quaternary solid solution Bi 2 O 2 (Te x Se 1-x ) and ternary, intermetallic mixed crystals Bi 2 (Te x Se 1-x ) 3 . Using thermodynamic modeling of the solid solutions it is possible to calcu­ late complex heterogeneous equilibria between all phases of this phase diagram. As a result we can thermodynamically describe the observed phase relations: Bi 2 (Te x Se 1-x ) 3 ⊿H° m (298) = 0; ⊿S° m (298) = R[xlnx + (1-x)ln(1-x)] Bi 2 O 2 (Te x Se 1-x ) ⊿H° m (298) = Ω · x(1-x); O⊿S° m (298) = R/4 [xlnx + (1-x)ln(1-x)] Ω = 0,6 kcal/mol

The triphos ligand CH 3 C(CH 2 PPh 2 ) 3 reacts with Co(BF 4 ) 2 (aq) or Fe(BF 4 ) 2 (aq) in the presence of nitriles RCN to produce the pentacoordinate [triphosCo(NCR) 2 ](BF 4 ) 2 (1) or the hexacoordinate [triphosFe(NCR) 3 ](BF 4 ) 2 (2). With α,ω-dinitriles NC-X-CN dinuclear compounds [triphosFe(NC-X-CN) 3 Fetriphos](BF 4 ) 4 (X = (CH 2 ) 3 (3a) X = o-C 6 H 4 (3b) are formed. The compound [triphosFe((CH 3 ) 2 C=C(CN) 2 ) 3 Fetriphos](PF 6 ) 4 (3c) is obtained from FeCl 2 by addition of the triphos ligand, the dinitrile and NaPF 6 . All compounds are characterised by the usual analytical techniques including X-ray analy­ses. It is observed that the quadruply positively charged compounds 3 tend to associate the respective anions in pockets formed by the three segments of the Fe(NC-X-CN) 3 Fe bridg ing units.

HR-MAS NMR spectroscopy was utilized for the characterization of three cosmetic emul­sions. The emulsions had the same chemical composition and were prepared in the same way except the homogenization step. Magic angle spinning (M A S) of the emulsions was applied to improve signal resolution by eliminating susceptibility changes as well as residual dipolar interactions within the sample. Spin-lattice relaxation times (T 1 ) were determined according to the inversion recovery technique in the temperature range of -10 °C to 40 °C to find out phase changes of the sample ingredients. 1 H and 13 C NMR signals of the individual components were assigned by use of different 1D and 2D NMR experiments. The HR-MAS NMR technique offers many possibilities to further investigate samples between the liquid and the solid state.

A new strategy for the asymmetric syntheses of polysubstituted pyrano-furanoids using allylic sulfates derived from carbohydrate precursors and the dianion of diethoxycarbonyl acetone, catalyzed by Pd(0), is described.

A new class of 4-deoxy-4-([4-substituted-1-piperazinyl], [4-morpholinyl] and [4-(perhydrol, 4-thiazin-4-yl)])-2,3-anhydrolyxopyranosides (3a-g and 6a-g) were synthesized from epoxy triflate moities 2 and 5 and 4-substituted piperazines, morpholines and perhydro-1,4- thiazines, respectively, to test their antibacterial activity. The characterized series of new compounds was tested in vitro against E. coli ATCC11229, S. aureus ATCC6538 and C. albicans SATCC10231.

A new pigment was isolated from an osmotically-stressed culture of the lichen mycobiont of Opegrapha sp. and the structure was determined to be 5, 7-dihydroxy-6-hydroxymethyl-2-methoxy-1, 4-naphthoquinone by spectroscopic analyses.