Volume 51, Issue 11

The following mixed-stack donor/acceptor complexes {D · · · A } ∞ have been crystallized and their structures determined: { 1 ,2,4,5-tetramethylbenzene · · · tetrabromo-p -benzoquinone} ∞ , {hexamethylbenzene · · · tetrabromo-p-benzoquinone} ∞ , { ( 1 ,2 ,4,5-tetramethyl-benzene) 2 · · · tetrachloro -p -benzoquinone} ∞ , {pyrene · · · tetrafluoro-p-benzoquinone} ∞ , {pyrene · · · tetrabromo-p-benzoquinone} ∞ and {perylene · · · tetrabromo-p-benzoquinone} ∞ . They exhibit an interesting lattice packing, especially the 2:1 tripeldecker sandwich of tetrachloro-p-benzoquinone, which crystallizes in a herringbone pattern. Their interplanar distances are around 340 pm, i. e. two van der Waals π radii. None of them , however, exhibits in neither the donor nor the acceptor components significant structural changes due to complex formation. Their colours range from orange-red to black in the crystal and to green in H 2 CCl 2 solution. Their long-wavelengths charge transfer absorption maxim a correspond to a lowering in excitation energy of up to 2 eV relative to that of the components. The different charge transfer in the ground and excited states of the donor/acceptor complexes investigated is further discussed referring to data such as cyclovoltammetric reduction potentials as w ell as to results from semiempirical calculations based on the crystal structure data determined and including configuration interaction.

The following mixed-stack donor/acceptor complexes {D···A} ∞ have been crystallized and their structures determined: {hexamethylbenzene···3,5-dicyano-1-nitrobenzene hexamethylbenzene···3,5-dinitro-1-cyanobenzene} ∞ , {pyrene···3,5-dinitro-1-cyanobenzene} ∞ , {anthracene···(3,5-dinitro-1-cyanobenzene) 2 } ∞ , {N,N-dimethylanilin···3,5-dinitro- 1-cyanobenzene} ∞ and { 1-3-phenylenediamine···3,5-dinitro-1-cyanobenzene} ∞ . Their lattice packing consists of parallel layers, which contain either donors and acceptors as for hexamethylbenzene and pyrene or composite ones as in the 1:2 complex of anthracene with each one of the acceptors above and below its peripheral rings. The isostructural hexamethylbenzene complexes exhibit almost identical packing coefficients as well as a hexagonal coplanar arrangement of the C 6 (CH 3 ) 6 donors. Weak intermolecular van der Waals interactions are also observed between antiparallel cyano substituents. The interplanar n distances range between 334 and 353 pm, i. e. around 340 pm of two van der Waals n radii. In none of the complexes, however, significant structural changes in either the donor or the acceptor components due to the complex formation are observed. In both the crystals as well as in solution, the donor/acceptor complexes exhibit colours between yellow and red; their long-wavelength charge transfer absorption maxima, therefore, correspond to a lowering in excitation energy of only up to 1 eV relative to that of the components. The different charge transfer in the ground and the CT excited states is also discussed referring to other data such as vertical first ionization energies or interplanar distances {D···A}, as well as to results from semiempirical calculations based on the crystal structure data determined and including approximate configuration interaction.

Refluxing a slightly acidic n-BuOH solution of RhCl(PPh 3 ) 3 and 2-chloro-, 2,4-dichloro-, or 2,4,6-trichloroazobenzene affords cyclometalated complexes (1) via loss of one phosphine ligand and oxidative addition of the ortho -C-Cl bond. X-ray structural analysis indicates a trans-position of the two triphenylphosphine ligands. The reaction proceeds only in polar solvents like alcohols or dimethyl sulfoxide but not in toluene. In the presence of air or oxygen a hydrido complex was formed as a by-product.

By reaction of [N(C 4 H 9 ) 4 ] 2 [B 10 H 10 ] with 2, 2′-(C 5 H 5 N) 2 NH at 160 °C the 2-[2-(2-pyridylamino)- pyrid-5-yl]-closo-decaborate anion [2-{2-(2-(C 5 H 4 N)-NH)-(C 5 H 3 N)-5 }B 10 H 9 ] 2− is obtained which can be separated from excess [B 10 H 10 ] 2− by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose. The crystal structure of [P(C 6 H 5 ) 4 ] 2 [2-{2-(2-(C 5 H 4 N)- NH)-(C 5 H 3 N)-5 }B 10 H 9 ] has been determinated by single crystal X-ray diffraction analysis: monoclinic, space group P2 1 /n with a = 11.435(3), b = 22.923(2), c = 20.094(4) Å, β = 95,27(2)°, Z = 4. By influence of the substituent the B 10 cage is strongly distorted with B-B distances ranging from 1.522 to 2.188 Å. The 11 B NMR spectrum reveals the feature (2:1:7) of a B 10 cage with the substituent in the 2 position with a downfield shift of the ipso B atom at −20.2 ppm. The IR and Raman spectra exhibit characteristic BH stretching vibrations between 2416 and 2499 cm −1 and the (C-C) and (C-N) stretching vibrations in the range of 1306 to 1584 cm −1 .

By stereoselective ligand exchange reactions of [PtF 5 Cl] 2− and cis-[PtF 4 Cl 2 ] 2− with Br − mixtures containing seven different fluoro-chloro-bromo- and two fluoro-bromo-platinates(IV) are formed, from which trans-Cs 2 [PtF 4 ClBr] 4 t 11 and mer-Cs 2 [PtF 3 Cl c 2 Br] 3 m 2 c 1 have been isolated by ion exchange chromatography on DEAE cellulose. All threefold mixed complexes could be detected by in situ 19 F and 195 Pt NMR measurements. Due to the stronger trans influence of Cl in comparison with F on asymmetric F′-Pt-Cl′ axes the F atoms are deshielded and their signals δ( 19 F) are shifted on the average by 106 ppm to lower field as compared with δ( 19 F) of symmetric F-Pt-F axes. For the same reason the mean coupling constant 1 J(FPt) of 1857 Hz is 44 % higher than 1 J( FPt) of 1288 Hz. The substitution of a cis positioned Cl against Br causes shifts of -7,6 ppm for δ( 19 F) and of -8,4 ppm for δ( 19 F ). The cis influence on the coupling constants 1 J(F P t) and 1 J( FPt), on the average 4 Hz, is more than two orders of magnitude smaller than the trans influence. The coupling constants between inequivalent F atoms 2 J(FF) amounts to 44 Hz. The mean highfield shift of the l95Pt signals on exchange of one F for Cl is 1177, of one Cl for Br 210 ppm. Due to the increasing trans influence F < Cl < Br on the stretching vibrations of asymmetrically coordinated axes characteristic frequency shifts of up to 15 % are observed. The normal coordinate analyses performed on 4 t 11 and 3 m 2 c 1 reveal that the force constant f d (PtF) is by 15 % higher than f d (PtF), and that f d (PtCl′) is by 31 % higher than f d (PtCl). Very intense Raman bands at 277 and 267 cm −1 are explained by strong vibrational coupling of the π-deformation with a symmetric valence mode of the Cl -Pt-Br′axis.

We report on the first successful intercalation of organic cations in large crystals of 2H-TaS 2 by electrochemical methods. The following species have been intercalated: Tetramethylammonium, methylviologen and methylene blue. Whereas the first species can be intercalated in chemical equilibrium like the hydrated metal ions, the intercalation of the other two more complex cations is accompanied by side reactions. The most complex system is methylene blue/TaS 2 where we observe three different phases depending on the preparation conditions. The electrical resistivity as a function of temperature has been measured by a 4-point ac method on single crystals immediately after intercalation. All samples are superconductors, some of them having a transition temperature to the superconducting state T c of 4.9 K, which is quite high for organic molecule intercalation compounds of 2H-TaS 2 . The anomaly of the resistivity at 77 K in the empty host lattice is suppressed in all of the intercalated samples even at the very low charge transfer of n = 0.06.

The crystal structure of CsNaTe has been determined by X-ray diffraction of single crystals. The hygroscopic CsNaTe crystallizes in the tetragonal space group P4/nmm (Z = 2) with the cell parameters a = 527.6(1) and c = 847.8(2) pm. The structure was determined from 237 independent reflections by Patterson and Fourier methods (R 1 = 0.065; wR 2 = 0.080).

The donor-acceptor complexes [X-I-C 6 H 5 ] − with X − = Cl − and Br − have been prepared as tetraphenylphosphonium salts from iodobenzene and PPh 4 X in acetonitrile solutions. They form colourless single crystals, which were characterized by crystal structure determinations. PPh 4 [Cl-I-C 6 H 5 ]: Space group P2 1 /c, Z = 4. Lattice dimensions at -70°C: a = 1301.1(5), b= 1457.0(5), c = 1478.8(5) pm, β = 114.17(3)°. PPh 4 [Br-I-C 6 H 5 ]: Space group P2 1 /n, Z = 4. Lattice dimensions at 20°C: a = 1354.9(1), b= 1480.1(2), c = 1375.5(1) pm, β = 106.13(2)°. The halide ions are coordinate at the iodine atom of the iodobenzene molecule in a linear arrangement [X-I-C 6 H 5 ] − with bond lengths Cl-I of 327.9 and Br-I of 347.2 pm.

Colourless single crystals of the title compound are obtained from a saturated solution of NaOSiPh 3 in toluene in a humid atmosphere. We have characterized [Na 4 (OSiPh 3 )H 2 O) 3 ] by IR spectroscopy and by a crystal structure determination. Space group R3, Z = 6 , R = 0.056. Lattice dimensions at -70°C: a = b = 1540.3 pm, c = 2639.6 pm. The compound has the structure of a Na 4 O 4 heterocubane which is only slighty distorted and in which one of the sodium atoms is not hydrated and shows coordination number three.

PbCu 3 TeO 7 has been prepared from the element oxides by solid state reaction in air. Single crystal X-ray work led too orthorhombic symmetry, space group D 2h 16 -Pnma, a = 10.488(1), b = 6.353(2), c = 8.813(2) Å, Z = 4. Cu(1)O 5 square pyramids and TeO 6 octahedra are members of the anionic part of the crystal structure, Cu(2) atoms show tetrahedral coordination by oxygen. The Cu(2) 2+ and the Pb 2+ cations are incorporated into a [Cu(1) 2 TeO 7 ] network. PbCu,TeO 7 can thus be viewed as a lead copper oxocuprate(II) tellurate. Calculations of the Coulomb terms of lattice energy reveal two possible positions for the lone pair of electrons at Pb 2+ .

Ag 8 Ge 3 O 10 was obtained from a mixture of the binary oxides by solid state reaction in the presence of a small amount of water which is acting as an accelerator. Conditions applied were T = 500 °C and p(O 2 ) = 1,2 kbar. According to an X-ray crystal structure analysis the title compound contains four crystallographically independent trigermanate [Ge 3 O 10 ] 8− ions per unit cell (Pc, a = 12.1549(11), b = 10.7375(14), c = 18.5169(20) Å, β = 92.326(10)°, 13448 independent reflections, R1 = 6 ,1 %, wR2 = 13,0%, Z = 8). Thermal decomposition, as recorded by DTA and temperature dependent Guinier photographs, occurs at 520 °C. Ag 8 Ge 3 O 10 is diamagnetic with a molar susceptibility of -330 ·10 −6 cm 3 mol −1 .

The ylide Ph 3 P=C=PPh 3 reacts with Fe(CO) 5 in toluene to give the metallacumulene (CO) 4 Fe=C=C=PPh 3 (1) and O=PPh 3 . A mixture of the ylide with its hydrolysis product Ph 2 P(O)-CH=PPh 3 produces the trinuclear cluster Fe 3 (CO) 9 (μ 3 -η 2 -C≡CPPh 3 ) (2) in low yields which can also be obtained from 1 and Fe 2 (CO) 9 . Both compounds contain the same ligand bonded in a terminal (1) and in a bridging (2) manner. 1 and 2 crystallize in the monoclinic space groups P2(1)/n and P2(1)/c, respectively, with the unit cell parameters a = 1008.35(10), b = 1167.89(10), c = 1875.10(10) pm, β = 99.824(10)° for 1 and a = 853.6(2), b = 1966.6(4), c = 1770.2(4) pm; β = 99.05(3)° for 2. The compounds are further characterized by IR and NMR ( 13 C , 31 P) spectroscopy and elemental analyses.

A new trirutile MTa 2 O 6 was synthesized by thermal decomposition of a freeze dried Cu- Ta-oxalate precursor. Its formation takes place preferentially starting from Cu-rich precursor compositions. Above 1000°C decomposition leads to the already known perovskite like structure with a composition Cu 1.05 Ta 1.98 O 6 . The degree of the orthorhombic distortion of the perovskite unit cell depends on the conditions during the cooling process after perovskite formation.

The titanocene complex 1b reacts with triethyl and trimethyl phosphite to yield the phosphonoesters 3a,b, which exist in solution as a mixture of two interconvertable conformers. The titanocene complex la is alkylated by trimethyloxonium tetrafluoroborate to form the 1,3-dithiolium tetrafluoroborate 10. The latter interacts with 9 (the lithium salt of 3a) merely by proton transfer restoring 3a. 9 condenses with aldehydes and ketones in a Horner- Wadsworth-Emmons reaction to give the titanocene complexes 16 as main products and the 4.5-bis(ethylthio)-1,3-dithiole-2-ylidene compounds 17 as byproducts.

Bis(η 5 -cyclopentadienyl)tungstendihydride reacts with iPr 2 BCl, BCl 3 or BF 3 to give the saltlike compounds [Cp 2 WH 3 ]iPr 2 BCl 2 (1a), [Cp 2 WH 3 ]BCl 4 (b), and [Cp 2 WH 3 ]BF 4 (c) with a bis(η 5 -cyclopentadienyl)trihydridotungsten cation and a borate anion. Compound 1a crystallizes in the space group P2 1 /n.

The sulfimide complex Fe 2 (CO) 6 (μ-SNH) (1) reacts with Co 2 (CO) 8 to form a 1:1 mixture of the known clusters FeCo 2 (CO) 9 (μ 3 -S) (2) and FeCo 2 (CO) 9 (μ 3 -NH) (3). The azatetrahedrane 3 may be used as a precursor for the synthesis of the new aza-trimetalla tetrahedranes Fe 2 Co(CO) 9 (μ-H)(μ 3 -NH) (5), CpMoFeCo(CO) 8 (μ 3 -NH) (6), CpNiFeCo(CO) 6 (μ 3 -NH) (7) and (CpNi) 2 Fe(CO) 3 (μ 3 -NH) (8) which were obtained from exchange reactions of 3 with Na 2 [Fe(CO) 4 ], Na[CpMo(CO) 3 ] and [CpNi(CO)] 2 . However, the reactions of 3 with Na 2 [Fe(CO) 4 ] and Fe 3 (CO) 12 gave Fe 3 (CO) 9 (μ-H) 2 (μ 3 -NH) (9) only as a minor product in addition to large amounts of Fe 3 (CO) 9 (μ-H) 2 (μ 3 -S) (10). The 1 H NMR spectra of 3 and 5 - 9 show a broadened triplet for the NH proton between δ( 1 H) 8.21 and 9.53. Chemical shifts δ( 14 N) were determined most efficiently by heteronuclear 1 H { 14 N} double resonance experiments. The δ( 14 N) values for aza-trimetalla tetrahedranes (-180 to -202) indicate delocalized bonding between the μ 3 -bridging nitrogen atom and the metal triangle.

The reaction of N-methylisatoic anhydride with 2-morpholinoethylamine or 1-aminoadamantane furnished N-methyl-N′-(2-morpholinoethyl)anthranilamide 1 and N-methyl-N′- ( l-adamantyl)anthranilamide 2, respectively. 1 and 2 are intermediates in the synthesis of the 2-chloro-3-methyl-1,3,2 λ 3 -diazaphosphorinones 3 and 4 by reaction of 1 and 2 with PCI 3 . The reaction of 3 with bis(2-chloroethyl)amine hydrochloride/triethylamine or (2-chloroethyl)amine hydrochloride/triethylamine formed the 2-substituted diazaphosphorinones 5 and 6. Hydrolysis of 3 led to the 2-oxo-λ 4 P-compound 7. The reaction of 6 with hexafluoroacetone furnished the (λ 5 ) phosphorane 8. 5 reacted with C 7 H 8 Cr(CO) 4 to form complex 9 whereas oxidation of 5 with the H 2 O 2 : urea 1:1 adduct yielded the phosphoryl compound 10. The crystal structure of 1 displays two independent molecules that show different chain conformations. Both molecules form chains parallel to the y-axis by intermolecular N (amide)-H···O(amide) bonds. The crystal structure of 6 shows a half-boat conformation for the phosphorinone ring; the P atom lies out of the plane. Again the molecules are linked by H-bonds into chains parallel to the y-axis.

Triphenylphosphine gold(I) complexes (Ph 3 P)Au(4,4′-dichloroindigo-H + ) and [(Ph 3 P)Au] 2 - (4,4′-dichloroindigo-2H + ) and (Ph 3 P)Au-L (LH = isatin, 5-bromoisatin, 2-indolinone) were prepared and characterized. The structure of the gold(I) complex of the monoanion of 4,4′- dichloroindigo (1) which was determined by X-ray diffraction, shows a slight deviation from the linear P-Au-N [ 169,5(4)°] arrangement with a short Au-N [206(1) pm] and a long Au-O(C) [267(2) pm] distance. In the crystal the complexes 1 and [(nBu 3 P)(Cl)Pd][indigo-H + ) form centrosymmetric pairs with parallel arrangement of the two indigo ligands.

Vilsmeier formylation of the oporphyrin-I tetraethyl ester Ni-complex (III) followed by reduction of the intermediary imine salt (IV) with NaBH 4 gave the o-dimethylaminomethyl-coproporphyrin-I Ni-complex (V). Heating the latter in methyl iodide gave 65% of the ethane- bis-porphyrin (I), which has been characterized by NMR-spectroscopy and a molecular and crystal structure investigation. The crystal structure shows an extended structure of the bisporphyrin with a parallel arrangement of the porphyrin subunits. Crystal data: I - C 90 H 106 N 8 Ni 2 O 16 . Triclinic, a = 12.319(3) Å. b = 13.297(3) Å, c = 14.444(3) Å, α = 105.56(2)°, β = 100.82(2)°, γ = 112.98(2)°, V = 1981.0(7) Å 3 , Cu Kα radiation, λ = 1.54178 Å, space group P1̄, Z = 1, R = 0.07.

5-(1-H ydroxycyclohexyl)-trans -3-pentenoic acid (2a) and 5 -(2 -hydroxy-2 -indanyl)-trans-3-pentenoic acid (2b) both exhibit associated structures in the solid state that contain strictly alternating repetitive -OH / HO 2 C- hydrogen bonded arrays. The (2a)„ structure is helical, whereas the association of 2b leads to a three dimensional assembly of tube-like (2b)„ structures. In contrast, the related sterically shielded 6,6-diphenyl-6-hydroxy-trans -3-hexenoic acid (2c) exhibits only a conventional carboxylic acid dimer structure in the solid state.

Derivatives of 3-oxo-camphorsulfonimide (1) with two phenylethynyl groups in the endo positions at the carbons C-2 and C-3 were prepared, and their reactivity towards halogenes and titanium chloride was studied. In every case, the two ethynyl groups led to the annulation of a five-membered ring to the bicyclo[2 .2 .1] system in an orientation which depends on the bulkiness of the additional substituent in position 3. NMR studies show that cationic species like 6 and 8 are the first detectable intermediates. They not only contain the fused five-membered ring but also a bond between its exocyclic methylene carbon and an oxygen atom of the sulfonyl group, thus transferring the positive charge mainly to sulfur. Semiempirical calculations (PM3) suggest two intermediates in the formation of such cations.

The structures of t-butylaminotriphenylphosphonium iodine dibromide and iodine dichloride were determined by Raman spectroscopy and Xray crystallographic structure analysis. The iodine dibromide [IBr 2 ] − species was assigned a centrosymmetric nature, whereas the iodine dichloride [ICl 2 ] − possesses a non-centrosymmetric structure.

Treating (MeSO 2 ) 3 N with 4-dimethylaminopyridine in MeCN afforded the ionic title compound (monoclinic, space group P2 1 /c). The bond lengths of the 4-dimethylaminopyridinium moiety suggest a semiquinoid resonance form with a double bond to the exocyclic nitrogen and two localized carbon-carbon double bonds in the ring. The ring and the exocyclic N and S atoms of the cation are essentially coplanar. The S -N bond distances in the cation (173.4 pm) and the anion (159.1 and 159.6 pm) correlate with Pauling bond orders of 1.0 and 1.7, respectively. The anion displays a staggered conformation with approximate C 2 symmetry ( S - N -S 120.4°).