Volume 50, Issue 5

Single crystals of AgCdVO 4 have been prepared in closed silver tubes using V 2 O 5 as a flux. The light-orange crystals show orthorhombic symmetry, space group D 16 2h -Pnma, a = 9.786(2), b = 6.994(1), c = 5.439(1) Å, Z = 4. The hitherto unknown AgCdVO 4 is related to the Olivine structure but isotypic to Ag 2 CrO 4 and NaCd 4 (VO 4 ) 3 respectively. The differences in crystal chemistry between the Olivine type, NaCd 4 (VO 4 ) 3 and AgCdVO 4 are discussed.

Single crystals of (Cu,Co) 3,75 Mo 3 O 12 have been prepared by recrystallization from melts and investigated by X-ray diffractometer techniques. The compound crystallizes with orthorhombic symmetry, space group D 16 2h -Pnma, a = 5.092(1), b = 10.624(3), c = 17.804(4) Å, Z = 4 and is isotypic to NaCo 2.31 Mo3O 12 . The crystal structure is discussed and it is shown, that the trigonal prismatically coordinated copper positions are occupied in a different manner. One of the alternate sites is beside the centre of the prisms, and the other one is shifted towards one of the faces of the rectangular prism. This detail may be interpreted by assigning the valance states Cu I and Cu II . The MO 6 octahedra are occupied statistically by copper and cobalt.

Black single crystals of Cr 0.761 Ta 2.095 O 6 have been prepared by CO 2 -LASER techniques. This phase crystallizes with monoclinic symmetry, space group C 5 2h -P2 1 /c, a = 4.748(1). b = 4.750(2), c = 10.405(3) Å, β = 117.152(13)°, Z = 2. The crystal structure is closely related to the trirutile type, although the metal positions are partly statistically occupied by Cr 2+ and Ta 5+ or underoccupied by Ta 5+ , respectively. FeTa 2 O 6 , prepared by the same m ethod does neither show any statistic occupation nor deviations from the trirutile structure, space group D 14 4h -P4 2 /mnm, a = 4.7595(5) Å, c = 9.201(2)A, Z = 2 .

Single crystals of the hitherto unknown compound CuSbMo 2 O 8 were prepared by recrystallization from melts in closed copper tubes and investigated by X-ray diffractometer technique. CuSbMo 2 O 8 crystallizes in a new structure type with monoclinic symmetry, space group C 6 2h - I12/a1, a = 5.554(2), b = 4.916(1), c = 21.519(4) Å, β = 93.42(3)°, Z = 4. The crystal structure shows Sb III in a one-sided coordination by four oxygen. Molybdenum shows the rare octahedral coordination by oxygen. MoO 6 and CuO 6 octahedra form triple layers stacked and connected by Sb ions along [001].

[Cs 4 (dibenzo-18-crown-6) 3 ](S 6 ) 2 ·2CH 3 CN has been prepared from dibenzo-18-crown-6, Cs 2 CO 3 and suifur in acetonitrile saturated with H 2 S. The title compound crystallizes in space group P 1̄ (lattice dimensions: a = 10,507(7) Å, b = 11,504(6) Å, c = 17,792(9) Å, α = 97,86(4)°, β = 105,86(4)°, γ = 101,48(5)°) with one formula unit. The crystallographic units are built of stacks of three crown ether molecules and two hexasulfide chains with the cations located between them. The conformation of the hexasulfide chains is all-cis.

The mixed valence compound Ga 1.93 V 0.97 S 4 has been prepared and characterized by X-ray powder methods. The compound crystallizes in an α-FeGa 2 S 4 structure. The lattice parameters of the hexagonal cell are a = 363.6 and c = 1207.1 pm. The structure has been refined by Rietveld methods.

The resolution of the racemate (BzlOCH 2 )(Me)C (COOH)(COOEt) (±)1 is the entry point for the enantioselective synthesis of the key compound 7 (MeC(CH 2 Cl)(CH 2 Br)(CH 2 OTfl)). Successive phosphination of 7 furnishes the triphosphine 10 (MeC(CH 2 PPh 2 )(CH 2 DBP)(CH 2 P(3,5-Me 2 C 6 H 3 ) 2 ) in both enantiomeric forms (DBP = dibenzophospholyl). The structures of the precursors (+)8S(MeC(CH 2 PPh 2 )(CH 2 DBP)(CH 2 Cl)) and (±)9 (MeC(CH 2 Br)(CH 2 Cl)(CH 2 DBP)) have been confirmed by X-ray analysis.

Reduction of Mes 2 BiBr with Na in liquid NH 3 or with Cp 2 Co in THF or C 6 D 6 gives Mes 4 Bi 2 (1) as a red solid that reversibly becomes pink on cooling with liquid nitrogen. Oxidation of 1 in air, or reaction of Mes 2 BiBr with NaOH, gives (Mes 2 Bi) 2 O (2). (Mes 2 Bi) 2 S (3) and (Mes 2 Bi) 2 Se (4) are formed by reaction of Mes 2 BiBr with Na 2 S in water or with Na 2 Se in liquid NH 3 , respectively. (Mes 2 Bi) 2 Te (5) is obtained by reaction of 1 with Te or by reaction of Mes 2 BiBr with Na 2 Te. Reactions of Me 4 Bi 2 with Se or Te produce (Me 2 Bi) 2 Se (6) and (Me 2 Bi) 2 Te (7). With equimolar amounts of p-benzoquinone tetramethyldibismuthane yields 1,4-C 6 H 4 (OBiMe 2 ) 2 (8). 1 H NMR data and mass spectra of 1-8, UV-VIS data of 1-4, and the crystal structures of 2·0,5C 2 H 5 OH, 3 and 4 are reported.

Di-n-butyltin dimethylphosphinate has been synthesized by the reaction of (n-Bu) 2 Sn(OCOCH 3 ) 2 with HO 2 PMe 2 in benzene. The ractions of (n-Bu) 2 Sn(OCOCH 3 ) 2 with MePhPOCl and Ph 2 POCl in toluene have been used to prepare (n-Bu) 2 Sn(O 2 PMePh) 2 and (n-Bu) 2 Sn(O 2 PPh 2 ) 2 respectively. On the basis of vibrational spectra and physical properties it is conclu ded that the title compounds are polymerized and the ligands function as O-P-O bridges between the tin atoms. The n-butyl groups are in trans position in the resulting octahedral environment around tin. Loss of n-butyl radicals and of the diorganophosphinate group from tin represent the main fragmentation processes in the El mass spectra of (n-Bu) 2 Sn(O 2 PRR′) 2 (RR′=Me 2 , MePh, Ph 2 ). The mass spectra show Sn(O 2 PRR′) + as the base peak.

Cyclopentadienyl nickel complexes [(C 5 H 2 tBu 3 -1,2,4)Ni(M-CO)] 2 (1) and [(C 5 HiPr 4 )Ni(μ-CO)] 2 (2) have been synthesized from nickel tetracarbonyl and the corresponding lithium cyclopentadienide, and [(C 5 iPr 5 )Ni(μ-CO)] 2 (3) has been obtained in high yield from nickel tetracarbonyl and the free pentaisopropylcyclopentadienyl radical. The crystal structure of 1 shows a complex on a crystallographic mirror plane with a bent Ni-C-Ni-C core whereas the crystal structure of 2 exhibits two independent planar molecules possessing crystallographic inversion symmetry.

Pale bluish-green single crystals of the new compound CuTb 2 [B 8 O 16 ] have been obtained by a B 2 O 3 flux technique. They crystallize in an unknown structure type. X-ray investigations on single crystals led to the space group C 5 2h -P2 1 /c (Nr. 14) with lattice parameters a = 1024.6(1); b = 834.93(6); c = 622.87(6) pm , β = 90.45(2)°; Z = 2. The structure contains 1 ∞ [B 8 O 16 ] 8- chains isolated from each other, which include tri- and tetracoordinated boron. The chains consist of alternating twelve- and eight-membered rings of boron and oxygen connected by BO 4 units. Tb 3+ is octacoordinated and Cu 2+ is hexacoordinated in elongated octahedra by oxygen. The relation to the crystal structures of Tb[B 3 O 6 ] and CuTb[B 5 O 10 ] is pointed out.

Single crystals of the compounds CuM[B 5 O 10 ] (M = Tm 3+ (I), Lu 3+ (II) have been obtained by a B 2 O 3 flux technique. Their structures are isotypic with CuTb[B 5 O 10 ]. X-ray investigations on single crystals led to the space group C 21 2v -Iba2 (Nr. 45); I: a = 622,0(2) pm; b = 844,7(1) pm; c = 1266,3(4) pm; Z = 4 and II: a = 618.4(1) pm; b = 845,9(2) pm; c = 1260,9(4) pm; Z = 4. The structure contains 1 ∞ [B 5 O 10 ] 5- chains that include twelve membered rings of boron and oxygen. Each ring consists of two tetrahedral BO 4 and two planar B 2 O 5 groups and is connected with neighboring rings via the BO 4 units. M 3+ (M = Tm 3+ , Lu3 + ) is eight-coordinated, while Cu 2+ is hexa-coordinated by oxygen.

By reduction of [B 6 H 3 (NO)B 6 H 5 ] 3- with Fe 2+ in aqueous alkaline solution [B 6 H 3 (NH 2 )B 6 H 3 ] 3- is formed. It reacts as a Brönsted base and becomes protonated in neutral medium to give the mono anion [B 6 H 6 (NH 2 )B 6 H 6 ] - . The crystal structure of the salt [As(C 6 H 3 ) 4 ][B 6 H 6 (NH 2 )B 6 H 6 ] has been determined by single crystal X-ray diffraction analysis; triclinic space group P1̄ with a = 8.284(2), b = 12.619(2), c = 15.5 4 3 (3 )Å and α = 69.193(13)°; β = 88.59(2)°, γ = 87.24(2)°. The 11 B NMR spectrum is consistent with mono hetero substituted octahedral B 6 cages with local C 4v symmetry. The IR and Raman spectra exhibit characteristic N-H , B-H and B 6 vibrations.

By treatment of protonated monoalkyl-closo-hexaborates [B 6 H 6 R] - . R = CH 3 , C 2 H 5 , n-C 3 H 7 , i-C 3 H 7 in aqueous alkaline solution with [As(C 6 H 5 ) 4 ]Cl the yellow orange deprotonated tetraphenylarsonium salts are precipitated, which react with methyl iodide or ethyl iodide to give dialkylated and protonated B 6 -compounds. The cisltrans isomers formed in a 1:1 ratio have been separated by ion exchange chromatography on diethylam inoethyl cellulose. Repeated deprotonation and reaction with methyl iodide affords mer-[B 6 H 4 (CH 3 ) 3 ] - . The crystal structures of cis-[P(C 6 H 5 ) 4 ][B 6 H 5 (CH 3 ) 2 ] (I), trans-[P(C 6 H 5 ) 4 ][B 6 H 5 (CH 3 ) 2 ] (II) and mer-[P(C 6 H 5 ) 4 ][B 6 H 4 (CH 3 ) 3 ](III) have been determined by single crystal X-ray diffraction analyses; I and II are monoclinic, space group P2/n, I with a = 11.8690(5), b = 7.2575(7), c = 15.8689(3) Å , β = 111.454(17)°; II with a = 13.2853(7), b = 7.4608(8), c = 13.3549(11), β = 93.5(11); III is tetragonal, space group P4/n with a = 13.363(2), c = 7.5051(13). The three methyl substituents are statistically distributed over four equatorial positions of the B 6 cage. The 11 B NMR spectra of the di- and trialkylated com pounds exhibit shifts of ipso-B atoms to lower, of antipodal-B atoms to higher field compared with [B 6 H 7 ] - . The IR and Raman spectra of the di- and trimethyl derivatives are similar to those of monom ethylhexaborate.

By reduction of [B 6 H 5 (NO 2 )] 2- with aluminium powder in aqueous alkaline solution the orange μ-dinitrogen-bis(pentahydro-closo-hexaborate)(2-), [B 6 H 5 (NN)B 6 H 5 ] 2- , is formed, which can be precipitated with tetraphenylarsonium ions. The crystal structure of [As(C 6 H 5 ) 4 ] 2 [B 6 H 5 (NN)B 6 H 5 ] has been determined by single crystal X-ray diffraction analy­sis; tetragonal, space group P4/n with a = 12.6610(12), c = 14.6790(11) Å. The B 6 cages are slightly compressed (2%) in the direction of the connecting linear N 2 bridge with bond lengths N-N of 1.129 and B-N of 1.421 Å. The 11 B NMR spectrum exhibits signals at -27.0 (ipso-B), +1.26 (equatorial-B), +3.54 ppm (antipodal-B atoms). The NN stretching vibration is observed in the Raman spectra as a very strong line at 2065 cm -1 .

Lithium tetrahydrogen cyclopentaphosphide. LiH 4 P 5 (I). has been obtained by metalation of P 2 H 4 at -78 °C with either n-BuLi or LiPH 2 in polar solvents. Upon suitable performance of the reaction, compound I can be isolated at low temperature as a lemon-yellow solvent adduct. The structure as the monolithium salt of (PH) 5 was confirmed by a complete analysis of the 31 P{ 1 H}-NMR spectrum. On warming above -35 °C, disproportionation occurs yield­ing Li 2 HP 7 . P 2 H 4 . and PH 3 . The reaction with n-BuLi produces the open-chain phosphides LiH 4 P 3 . LiH 3 P 2 , and LiPH 2 . The NMR parameters of LiH 3 P 2 and LiH 4 P 3 are reported. Reac­tion of 1 with P 2 H 4 gives rise to the bicyclic and polycyclic phosphides LiH 4 P 7 , LiH 5 P 8 and Li 2 H 2 P 14 , respectively.

In a single pot synthesis consecutive reaction of the tetradentate amine-thiole H 2 - ' S 2 N 2 H 2 ' 2 ('S 2 N 2 H 2 ' 2- = 1,2-ethanediamino-N,N'-bis(2-benzenethiolato)(2-)). with [LiN(SiMe 3 ) 2 ] and benzyl chloride (BzCl) yields the amine-thioether 'Bz 2 S 2 N 2 H 2 ' which gives the tertiary amine-thioether 'Bz 2 S 2 N 2 Me 2 ' when reacted with further [LiN(SiMe 3 ) 2 ] and CH 3 I Removal of the benzyl groups with an excess of sodium and acidification with hydrochloric acid finally yield H 2 - ' S 2 N 2 Me 2 ' I ('S 2 N 2 Me 2 ' 2- = 1,2-ethanediamino-N,N'-di- methyl-N,N'-bis(2-benzenethiolato)(2-)). 1 and 2 have been characterized by X-ray structure analysis. With [Ni(CH 3 COO) 2 ] · 4H 2 O,1 yields racemic [Ni('S 2 N 2 Me 2 ')] 3 in a diastereospecific reaction. Crystallization of 3 leads to spontaneous resolution of the racemate. By X-ray structure analysis of 3 the absolute configuration in the single crystal examined was determi­ned using Roger's μ-refinement (μ = 1.00(4)). Upon reaction with [RuCl 3 ·3H 2 O]. LiOMe and CO. I yields [Ru(CO) 2 ('S 2 N 2 Me 2 ')] 5. Spectroscopic data indicate that 5 and the parent complex [Ru(CO) 2 ('S 2 N 2 H 2 ')] differ with respect to their core structures. Influence of the amine methylation on structure and reactivity of complexes with [M('S 2 N 2 R 2 ')] cores, R = H. Me, is discussed.

K 19 Pb8O 4 (OH) 3 crystallizes in the cubic system with space group Fm3m (a = 1622.7(4) pm: Z = 4). KPb crystallizes with the NaPb structure type (tetragonal, space group 14 1 /acd, a = 1153.2(6) pm. c = 1886.8(9) pm. Z = 32). The crystal structures of both com­pounds contain Zintl-anions [Pb 4 ] 4- as characteristic building units, which in the Zintl phase are separated by potassium cations only. The oxide-hydroxide contains additional anions O 2- and OH - enclosed by potassium ions in an octahedral coordination. The oxygen centered octahedra form a three-dimensional network of clusters [(O/OH) 6 K 19 ] (consisting of six octahedra [(O/OH)K 6 ] sharing edges) and single octahedra [OK 6 ] connected by com­mon corners. Tlie [Pb 4 ] 4- tetrahedra occupy the voids within this framework.

The adduct formation between 2-trimethylstannyl-pyridine (1) and triethylborane, leading to 2a, and 9-borabicyclo[3.3.1]nonane, leading to 2b, was studied by 1 H, 11 B, 13 C, 15 N and 119 Sn NMR in solution. Changes in the magnitude of the coupling constants J( 119 Sn, 13 C), with respect to the data for I, were analysed. The absolute signs have been determined [all coupling constants n J( 119 SnZ 3 C) to methyl and pyridine carbon atoms in 1 to 3 possess a negative sign and the same is true for n J( 119 Sn, 1 H) of the pyridine hydrogen atoms] by various two-dimensional NMR experiments, and attributed to the influence of the lone pair of electrons at the nitrogen atom in 1. The NMR spectroscopic results for the 1,4-dihydro- 4a,1,4-azastannabora-naphthalene derivative 3, in which structural fragments are present analogous to those in the borane adducts 2, correspond to those for 1 and 2a,b. The molecu­lar structure of 3 has been determined by X-ray analysis [orthorhombic; P2 1 2 1 2 1 , a = 713.9(2), b - 1566.0(2), c = 1578.4(2) pm]. Solid-state 13 C and 119 Sn CP/MAS NMR spectra prove that the molecular structures of 3 in the solid state and in solution are very similar.

The complex [(TMEDA)Ni(μ-H,μ-CO)Ni (TMEDA)]X 1a (TMEDA: N,N,N',N'-Tetramethylethylenediamine, X: Monoanions of cis-cyclohex-4-ene- or cyclohexane-dicarboxylic acid) could be isolated as the product of a stepwise reaction in THF solution of Ni(COD) 2 , TMEDA and cis-cyclohex-4-ene-dicarboxylic-anhydride in the presence of a small amount of water. Similar results are obtained with cyclohexane-dicarboxylic-anhydride. NMR- and IR-spectroscopic measurements and the single crystal X-Ray diffraction analysis of 1a have established the structure: Both a hydride- and a carbonyl bridge are linking two (TMEDA)Ni fragments in the cationic part. The Ni(I) centers are connected by a Ni-Ni-bond . The compounds are the first (TMEDA)Ni(I) complexes and the first binuclear hydrido-carbonylcomplexes which are stable without further bridging and π-acceptor ligands. They contain hydrido and protic hydrogen in the same compound.

The reaction of the series of methyl/phenylchlorosilanes Me 2 PhSiCl, MePh 2 SiCl and Ph 3 SiCl with CHBr 3 /n-BuLi to give the corresponding bromo-di(silyl)methanes has been investigated. The selectivity of the reaction proved to be strongly influenced by the number of phenyl groups bound to silicon. As already established for Me 3 SiCl, Si-C coupling readily occurs with Me 2 PhSiCl to give (Me 2 PhSi) 2 CHBr (1) in good yields, whereas MePh 2 SiCl affords (MePh 2 Si) 2 CHBr (2) in lower yields. The molecular structures of 2 and the by-product (MePh 2 Si) 2 CBr 2 have been determ ined by single crystal X-ray diffraction. In the case of the fully arylated species, Ph 3 SiCl, only the monosilylated compound (Ph-Si)CH 2 Br (3) is generated. (HMe 2 Si) 2 CHBr (5) can be obtained starting from 1 by treatment with triflic acid to give (CF 3 SO 3 Me 2 Si) 2 CHBr (4), followed by reduction of 4 with LiAlH 4 in diethyl ether. In situ metalation of 5 with n-BuLi affords (HMe 2 ) 2 CHLi, which reacts instantaneously with a second equivalent of 5 to give the halogen-free dimer [(HMe 2 Si) 2 CH]SiMe 2 CH 2 SiMe 2 H (6).

Crystals of both complexes were obtained by evaporation of the ethanol solvent. The crystals of [{CuCl(C 10 N 4 H 24 )} 2 ][CdCl 4 ] are tetragonal, space group I4̄2d, Z = 4, a = b = 1784.1(11), c = 1101.1(8) pm. Each copper atom is bonded to one cyclam ligand and two chlorine atoms which are acting as bridging ligands and connect the copper atoms to chains of distorted octahedra. Distorted tetrahedra of CdCl 4 are situated in cavities between these chains. The crystals of [Cu(C 10 N 4 H 24 )][CdCl 3 (H 2 O) 2 ]Cl are monoclinic (b), space group C2/c, Z = 4, a = 1581.9(8), b = 1323.3(7), c = 924.0(5) pm, β = 94.31(5)°. Cadmium is coordinated to four chlorine atoms and two water molecules, while all of the chlorine atoms act as bridging ligands connecting every cadmium atom to two adjacent cadmium atoms and to two copper atoms which lie in plane with the N atoms.

Reactions of 1,4-diazabicyclo[2.2.2]octane (“dabco”) with K 2 [HgI 4 ] or Hg(SCN) 2 yield crystals of [Hg(dabco)I 2 ] (1) and [Hg(dabco)(SCN) 2 ] (2). 1 crystallizes monoclinically, space group P2 1 /a. Z = 4, a = 1211.6(5), b = 682.3(6), c = 1430.4(3) pm, β = 98.90(5)°; 2 is orthorhombic, space group Pmmn, Z = 2, a - 740.5(3), b = 609.1(4), c = 1220.0(8) pm. In 1 HgI 2 groups are connected by bridging dabco molecules to give a chain structure. The Hg atoms are tetrahedrally coordinated. In 2 the Hg atoms are bridged by two SCN ligands and the chains thus formed are again interconnected by bridging dabco molecules, whereby layers are formed. The coordination polyhedron for the Hg atoms is a distorted octahedron.

2-Methyl-1 H-benzimidazole 1 reacts in the presence of two equivalents of sodium hydride in dry DMSO with carbon disulfide to methyl 2-methylbenzimidazole-1-dithiocarboxylate 3 using methyl iodide as alkylating agent, whereas using 1,2-dibromoethane 1,1′-carbonothioyl bis(2-methyl-1 H-benzimidazole) 5 is formed. Compound 1 reacts with phenyl isothiocyanate in the presence of one equivalent of sodium hydride in dry DMF after alkylation to 2-methyl-1-( alkylthio-phenylimino)-1 H-benzimidazoles 6a, 6b. Reaction products 5 and 6b have been identified and structurally characterized by X-ray analysis.

Me 3 CSiHal 3 react with LiOCMe 3 to give Me 3 CO(Me 3 C)SiHal 2 (HaI = F (1), Cl (3)). The aminofluorosilane, Me 3 CO(Me 3 C)SiFNH 2 (2), is formed in the reaction of 1 with LiNH 2 . The diaminosilane Me 3 CO(Me 3 C)Si(NH 2 ) 2 (4) is obtained from the reaction of 2 with ammonia. 4 reacts with LiC 4 H 9 to give the lithium derivative Me 3 CO(Me 3 C)Si(NHLi)NH 2 (5). In a molar ratio 1:1 the reaction of 5 and 1 leads to the formation of the 1-amino-3-fluoro-disilazane Me 3 CO(Me 3 C)SiF- NH - SiNH 2 (CMe 3 )OCMe 3 (6) and in a molar ratio 2:1 to the four-membered silicon nitrogen ring [Me 3 CO(M e 3 C)Si-NH] 2 (7). The crystal structure of 7 was determined.

[SnCl 4 (Ph 2 PCH 2 -CH 2 PPh 2 )] CH 2 Cl 2 has been characterized by a crystal structure determ ination. Space group P2 1 /c, Z = 4, 5565 observed unique reflections with I > 2 σ(I), R = 0.043. Lattice dimensions at -70 °C: a = 1141.4(6), b = 2178.3(11), c = 1399.1(7) pm, β = 108.96(3)°. The complex forms monomeric molecules with the 1.2-bis(diphenylphosphino)ethane as chelating ligand. Bond lengths (average): Sn - P 266.7 pm, Sn - Cl 241.8 pm.

Four new ternary VO 2+ complexes, [VO HADP-dipy]. 6H 2 O , [VO HADP-ophen], 6H 2 O , [VO AMP-dipy], 6H 2 O and [VO AMP-ophen]. 6H 2 O (diny: α.α'dipyridyl; ophen: o-phenanthroline) were prepared and characterized by chemical analyses, electronic and vibrational spectra. Their bonding peculiarities are briefly discussed.