Volume 35, Issue 3

The structure of TlHg 5 Cl 11 , an example of the monoclinic phases MHg 5 X 11 (M _ TI, K, Rb, Cs, NH 4 ; X = Cl, Br), which are found in the system alkalihalide-mercury(II)halide, was determined by X-ray structure analysis. These compounds are double salts MX · 5 HgX 3 , because the structure is mainly formed from X - Hg - X units.

The structure of Tl 10 Hg 3 Cl 16 (tetragonal; space group I4/m; a - 849,0(2) pm, c = 2372,9(6) pm) was determined by X-ray structure analysis. This compound consists of HgCl 4 tetrahedra and linear Cl-Hg-Cl units, which are completed by four additional chlorides to distorted (2 + 4) HgCl 6 octahedra. A close relationship to the Tl 4 HgX 6 structure (X = Br, I) is discussed.

The tetranuclear complex Mo 4 O 8 ((CH 3 ) 2 POS) 4 has been synthetized by reacting MOCl 5 with Na((CH 3 ) 2 POS) in CHCl 3 /CCl 4 solutions. The structures of two crystalline modifications (I and II), containing different amounts of solvent, have been determined by X-ray crystallography. In both, four molybdenum and four oxygen atoms are situated at the corners of a highly distorted cube. Each Mo atom has a terminal oxo group. The Mo atoms form two MO 2 pairs through Mo-Mo bonds. The bidentate (CH 3 )POS- ligands coordinate to two Mo atoms of different pairs. The sulfur atoms of the ligands are partially replaced by oxygen atoms.

The crystal structure of the two spirocyclic diazadiphosphetidines (Me 2 C 2 O 2 )(Me 2 N) 2 P 2 N 2 (SiMe 3 ) 2 (1) and (Me 2 C 2 O 2 ) 2 (Me 2 N) 2 P 2 N 2 (SiMe 3 ) 2 (2) were determined. In both compounds the dimethylamino groups are arranged in a cis position with respect to the plane of the four-membered ring. There are no unusually long PN distances in the four-membered ring of 2, although 2 monomerizes easily and quantitatively at room temperature to give 3.

N-Organylamino-N′,N′-bis(trimethyl)amino-fluoroorganylsilanes react with butyl-lithium to give the corresponding lithium salts. Further reaction of these lithium salts with fluorosilanes leads to the formation of the expected substituted compounds. Diaza-disilacyclobutanes are formed by thermal LiF elimination in THF. The simultaneous 1,3-migration of a trimethylsilyl group from one nitrogen atom to another is demonstrated by the crystal structure determination of the products of two such reactions, with different substituent groups.

, The structure of the straight silanes Si n H 2n+2 (1 ≤ n ≤ 7) and of the branched isomers isotetrasilane, iso- and neopentasilane, 2-silyl- and 3-silylpentasilane, 2,3-disilyltetrasilane as well as 2-silyl- and 3-silylhexasilane could be unambiguously elucidated by 29 Si NMR spectroscopy. Systematic trends in the chemical shift and coupling parameters were observed and an empirical relationship between δ( 29 Si) of a 29 Si nucleus and the number of the neighbouring silicon atoms in αβ or γ position is given. In 1 H decoupled spectra the nuclear Overhauser effect on the 29 Si resonance was found to increase with increasing distance of the 29 Si nucleus from the end of the chain. A complete analysis of the multi spin systems of disilane, trisilane and isotetrasilane was performed and the signs of the 29 Si,H- and H,H-long range coupling constants were determined with regard to the negative sign of 1 J( 29 SiH).

The new compound BaNi 2 Si 2 crystallizes in the orthorhombic system, space group Cmcm-D 2h 17 with a = 650 ± 1 pm, b = 535 ± 1 pm, c = 1133 ± 2 pm. The structure can be interpreted as a distorted variant of the ThCr 2 Si 2 -type.

The salt (NH 4 ) 3 Ta 2 NBr 10 can be prepared from NH 4 Br und TaBr 5 at 400 °C in a sealed glas ampoule. The greenish yellow substance, which is sensitive to moist air, crystallizes in the tetragonal space group P4/mnc with Z = 2. The crystal structure is closely related to that of K 4 M 2 OCl 10 · H 2 O (M = Ru, Re). It is built up by NH 4 + cations and Ta 2 NBr 10 3- - anions. The anions possess the point symmetry D 4h and therefore show a symmetrical Ta = N = Ta bridge. The Ta-N distances of 185 pm can be interpreted by double bonds.

R 2 PNHPR 2 (1) (R = C 6 H 5 ) reacts with [(μ-Cl)Ir(C 8 H 12 )] 2 in a molar ratio of 4:1, to give the square planar, ionic complex [Ir(R 2 PNHPR 2 ) 2 ]Cl (2a). By reaction of 2a with NaBR 4 , [Ir(R 2 PNHPR 2 ) 2 ]BR 4 (2b) is obtained. Treatment of 2 a with CO gives [Ir(CO)(R 2 PNHPR 2 ) 2 ]Cl (3a). The complex 3a is also formed by the reaction of 1 with Ir(CO)(PR 3 ) 2 Cl (R = C 6 H 5 ) and Ir(CO) 2 (p-H 2 N-C 6 H 4 -CH 3 )Cl. 3a undergoes metathesis with NH 4 PF 6 to yield [Ir(CO)(R 2 PNHPR 2 ) 2 ]PF 6 (3b). The N-deuterated derivative [Ir(CO)(R 2 PNDPR 2 ) 2 ]Cl (4) is made by H/D exchange from 3a with CH 3 OD. Oxidative additions of O 2 , CS 2 , I 2 and (SCN) 2 to 2a yield [Ir(O 2 )(R 2 PNHPR 2 ) 2 ]Cl (5), [Ir(μ 2 -CS 2 )(R 2 PNHPR 2 ) 2 ]Cl (6), [Ir(I) 2 (R 2 PNHPR 2 ) 2 ]Cl (7) and [Ir(SCN) 2 (R 2 PNHPR 2 ) 2 ]Cl (8). Additionally K 2 [PtCl 4 ] and 1 reacts to [Pt(R 2 PNHPR 2 ) 2 ]Cl 2 (9). The new compounds are characterised, as far as possible, by their IR, FIR, Raman and 31 P NMR spectra.

Differing fragmentation of boron chelates of aromatic azo compounds confirms the structural formulae 1a-7c, presented in [2]. More significant differences are caused by the substituent of the boron R (F instead of C 6 H 5 ). Although certain rules can be deduced by the substitution of F for CeHs with regard to the change in intensity of the ions M + , M + -R (and others), in some cases the stable aromatic azo system causes a significant change in the fragmentation as compared with that of azomethine chelates. The chelates 7 eliminate “RH” and show no molecular ion. Apparently a second chelate ring is closed before further fragmentation can start. Fragmentation of 7 a and b is analogous to 5.

Bidentate chelate reagents incorporating a suitable group (e.g. OH, NH 2 ) in ortho position to the azo-group react with diphenylboronic acid anhydride or boron trihalides (BF 3 , BCl 3 ) resulting in the BR 2 -six membered ring-chelates of types 1 and 2. The products of the reaction of tridentate chelate reagents with phenylboronic acid or boron trifluoride at elevated temperature are BR-chelates with two six membered rings (types 3 and 4). The conditions of the formation of the bicyclic chelates 5 and 6 depend on the position of the substituents of the chelate reagents. The incorporation of only one BR 2 group is possible if the order of the substituents in 2,2′-dihydroxyazobenzenes is not symmetrical (chelates of the type 7). Structural isomers of boron chelates of the types 5, 6 or 7 with N α /N β isomerism have not yet been observed. The identification of the structures of the above-mentioned complexes was achieved by means of 1 H, 11 B and 19 F NMR and IR spectroscopy. For mass spectrometric analysis see ref. [2].

(AsPh 4 ) 2 [Re 2 FN 2 Cl 7 ] is prepared by the reaction of ReNCL 4 with AsPh 4 F in acetonitrile solution. The IR spectrum indicates a bridging Re-F-Re complex anion with terminal Re ≡ N ligands. The magnetic susceptibility was measured in the temperature range of 4.8-280 K. The effective magnetic moment is 1.66 B.M. per Re atom (θ = -0.5 K) and corresponds well with Re(VI). The magnetic moment of the well known PPh 4 [ReNCl 4 ] has also been studied {μ eff = 1.67 B.M.; θ = -1.2 K).

Pure S 4 N 4 is prepared by a new method from reduction of S 3 N 3 Cl 3 by various metals (Hg, Cu, Sn). Realized either in an inert solvent or directly in gaseous phase the reaction is complete. The stability range of NSCl has been determined by Raman spectrometry.

The hitherto unknown compound BaTi 8 O 16 was prepared by heating a mixture of BaO:TiO 2 = 1:4 in a vacuum furnace to 1400 °C (Ti crucible). Single crystal X-ray investigations show monoclinic symmetry (a = 1420,9, b = 297,1, c = 998,1 pm, β = 133,50°; space group C 2 3 -C 2 ). The crystal structure was found to be isotypic to α-MnO 2 .

Tl 2 PbGeS 4 was synthetized by fusion of a stoichiometric mixture of Tl 2 S, PbS, and GeS 2 , and prolonged heating of the reaction product. A single crystal could be isolated for intensity measurements on an automated four-circle single crystal diffractometer. Tl 2 PbGeS 4 is monoclinic, space group P2 1 /a with a = 8.907(2), b= 9.114(2), c = 10.502(3) Å, β = 94.08(2)°, and Z = 4. The crystal structure was determined by means of standard methods and refined to R = 0.065. The structure is composed of tetrahedral [GeS 4 ] 4- anions which are held together by Tl 1+ and Pb 2+ cations. The GeS 4 tetrahedra are only slightly deformed (mean distance Ge-S: 2.220 Å). The Tl atoms are surrounded by eight S atoms at distances ranging from 3.085 to 4.055 Å forming irregular coordination polyhedra. The Pb atom is coordinated by six S atoms in a strongly distorted octahedral arrangement at distances varying from 2.803 to 3.256 A. The Pb atoms and the Tl(2) atoms are alternately situated between slabs of GeS 4 tetrahedra parallel to the ab plane. The Tl(l) atoms are found within these slabs located between the GeS 4 tetrahedra.

[(COD)RhCl] 2 (COD = 1,5-cyclooctadiene) reacts with i-C 3 H 7 MgBr in the presence of 4-vinylcyclohexene and 1-methyl-1,4-cyclohexadiene to give the neutral, diamagnetic π-complexes [(COD)Rh(subst.-cyclohexenyl)] in which the central metal achieves a 16-electron valence shell. The catalytic activity of these complexes is described.

A series of ab initio molecular orbital calculations have been carried out on phosphacumulene ylides of the type H 3 P = C = C = X where X = S, O, CNH, and (OH) 2 . The variation in the P-C-C bond angle was examined and compared to the experimentally determined structures of analogs. The dominant factor in setting the P-C-C angle was found to be the relative π-acceptor capability of the C = X fragment in the plane of the bending motion. Quantitative PMO-arguments were constructed for the X = S, O and (OH) 2 cases along this line. It is also shown, that P-C σ* character mixes into the highest occupied molecular orbital. The magnitude of this effect is dictated by the amount of bending and this strongly influences the 1 J P-C nuclear spin coupling constants. Finally, the bending in H 3 P = C = PH 3 was also investigated in a similar manner.

The title compound (1) was crystallized as free ligand and as its (1 · KSCN) 2 · H 2 O complex. Crystallographic data are, for the former: space group C 2/c, a = 31.110(9), b = 4.608(4), c = 17.188(6) Å, β = 105.27(8)°, Z = 2, D m = 1.25 gem -3 ; for the latter: space group P2 1 , a = 11.044(3), b = 18.310(4), c = 14.485(4) Å, β = 97.49(2)°, Z = 4, Dm = 1.27 gem -3 . Crystal structures were solved by direct methods using X-ray diffraktometer data and least squares refinements converged at 10.8% for 1 and at 7.6% for (1 · KSCN)2 · H2O. The free ligand (1) is S-shaped and, upon K + -complexation, changes signs of some gauche O-C-C-O torsion angles while C-C-O-C angles remain trans. In (1 · KSCN) 2 · H 2 O, there are two complex molecules 1 A · KSCN · H 2 O (I) and 1 B · KSCN (II). The ligands are wrapped circularly around K + and coordinated with only four of the five polyether oxygens. K + interacts further with H 2 O in (I) and with N of SCN - in II and, in both complexes, with acetylamino oxygen of adjacent 1. The latter interaction leads to polymeric structures not observed previously for similar complexes.

Extended photolysis of pentacarbonyliron in neat 2,3-dimethylbutadiene results in dimerization of the diene and formation of tricarbonyl(η 4 -1,5-dimethylene-2,6-dimethylcyclooctane) iron (1). The structure of complex 1 is characterized by a trigonal-bipyramidal geometry whereby the exocyclic double bonds of the diene ligand and one of the carbonyl groups lie exactly in the equatorial coordination plane.

The D- and L-enantiomers of the wild oat herbicide diclofop-methyl (title compound) were prepared utilizing resolution operations and by synthetic routes with optically active compounds as starting material. The dextro-rotatory product which the D(R)-configuration can be attributed to, was found to be the herbicidally active species.

The thermal dimerization of monothiobenzil (1c) to a 1,3-dithietane (2c) and the photochemical cycloreversion of this heterocycle to 1 c is described.

21,24-Dimithylaetiobiliverdin-IV-γ was prepared via excessive methylation of aetiobili. verdin-IV-γ. Its configuration could be established using 1 H NMR methods. Photoisomerisation yields the (E,Z,Z) and (E,Z,E) diastereomers which means that the selectivity observed in photoisomerisation of bilatrienes-abc can be removed by making the ligands of the lactame moiety adjacent to exocyclic double bonds nearly equal. The torsional angles at the methine single bonds are approximatly equal in the three diastereomers resulting in much the same UV-VIS spectra. The obviously strong distortion of the conjugated chromophor allows for the deceleration of certain radiationless deexcitation paths thereby allowing for photoisomerisations in homogenous solution.

A number of new hydroxyphenothiazines (2) are synthesised by the reduction of corresponding 3H-phenothiazin-3-ones with sodium dithionite and zinc dust-acetic acid. The oxidation of acetoxyphenothiazines (3) with H 2 O 2 in acetone-ethanol provided directly substituted 2-methoxyphenothiazin-3-ol-5-oxides (5). Two series of acetylated derivatives viz. O- and O,N-acetylated of 2 were prepared.

Di-(2-hydroxy-1-phenazinyl)methane, Phenazines, Bacterial Constituents, Pseudomonas aureofaciens The structure elucidation of di-(2- hydroxy-l-phenazinyl)methane from Pseudomonas aureofaciens is described. In addition to the phenazine derivatives isolated earlier from this bacterium 2,3,4-trihydroxyphenazine.

Single crystals of Nd 2 NiO 4 were prepared by plasma and CO 2 -LASER technique and analysed by X-ray single crystal methods. Nd 2 NiO 4 is the first compound of the orthorhombically dis-torted La 2 CuO 4 -type.

Investigations of the systems Ca(Sr)-Ni-As resulted in the discovery of three ternary phases. CaNi 2 As 2 and SrNi 2 As 2 are isotypic and crys-tallize in the ThCr 2 Si 2 -structure (space group I 4/mmm) with the following constants: CaNi 2 As 2 a = 406.5(1) pm, c= 994.9(2) pm, SrNi 2 As 2 a = 415.4(1) pm, c = 1029.0(2) pm. Ca 2.3 Ni 11.7 As 7 (a= 940.4(1) pm, c= 381.6(1)pm) crystallizes in a hexagonal lattice; a Zr 2 Fe 12 P 7 -structure is supposed.

Some iodo elpasolites Cs 2 LiM III I 6 (M III = Sc, Lu, Tm, Ho) and Cs 2 NaM III I 6 (M III = Sc, Lu, Tm, Er) have been prepared for the first time. According to Guinier-Simon X-ray powder photographs they belong to the elpasolite type structure (cubic K 2 NaAlF 6 -type and its tetragonal distorted variety: Cs 2 NaMI 6 ) or to the Cs 2 LiGaF 6 -type structure (trigonal: Cs 2 LiMI 6 ). The compounds Cs 2 LiTmX 6 (X = CI, Br, I) are further characterized by Raman spectra and magnetic susceptibilities.

A single crystal investigation of the high pressure - high temperature phase of BaGe 2 (α-ThSi 2 type of structure) has been performed. Space group I4 1 /amd has been derived from rotation, Weissenberg and precession photographs. On a four-circle-diffractometer 1082 reflections with 0 ≤ h ≤ 8, 0 ≤ fc ≤ 8, 2̅4̅ ≤ l ≤ 24 have been measured with filtered Mo-radiation. This results in 296 independent reflections. Data of the complete structural analysis are summarized in Tabs. I and II. The final R-values are R = 6.09%, R w = 4.19%, R g = 4.95%.

The reaction of p-benzoquinone with an excess of SbCl 5 gives 2,3,5,6 - tetrachloro-p-benzoquinone (“Chloranil”) in high purity and almost quantitative yield. 2,6- and 2,5-dichlorop- benzoquinone could be identified as intermediate products.

Irradiation of (η 5 -C 5 H 5 ) 2 Fe 2 (CO) 4 in the presence of 2,3-diazanorbornene affords (η 1 -2,3- diazanorbornene)-Fe 2 (η 5 -C 5 H 5 ) 2 (CO) 3 (1) and small amounts of (η 2 -2,3-diazanorbornene)Fe 2 -(η 5 -C 5 H 5 ) 2 (CO) 2 (2). 1 is converted into 2 upon heating but not upon photolysis.

The crystal structure of (H 3 O)[Al 3 (H 2 PO 4 ) 6 (HPO 4 ) 2 ] · 4 H 2 O contains layers consisting of AIO 6 octahedra which share vertices with O 2 P(OH) 2 and O 3 P(OH) tetrahedra. Within these layers there are vacancies (hollows) which are occupied by H 3 O + species. Water molecules are fixed between neighbouring layers by hydrogen bonds. The identity of some other related phosphates is discussed with respect to the crystal structure described in this paper.

The “novel 10π-system" reported earlier is a 2,1-benzisothiazole, a well-known heterocyclic system.