Volume 54, Issue 7

Treatment of (chloro)gold(I) complexes of di- and tetra-tertiary phosphines with equivalent quantities of sodium quinoline-2-thiolate in methanol / dichloromethane affords the corresponding (phosphine)gold(I) quinoline-2-thiolates in high yields. The di- and tetranuclear complexes, respectively, of α, ω-bis(diphenylphosphino)-propane (1), -butane (2) and -pentane (3) and of tris(2-diphenylphosphino-ethyl)phosphine (4) have been obtained as crystalline solids, and the structures of 2 and 4 have been determined by single crystal X-ray diffraction studies. Unexpectedly, the molecules of 2 are loosely aggregated into strings via weak intermolecular gold-sulfur, not via Au ∙∙∙ Au interactions. Compound 4 is a monomeric tetranuclear cluster in the solid state with two intramolecular gold-gold bonds. Bis(2-diphenylphosphino-ethyl)- phenylphosphine (PPP) forms trinuclear complexes with gold(I) chloride, bromide and iodide (5a - c). The iodide complex features a chain structure through intermolecular Au ∙∙∙ Au contacts between the two terminal P-Au-I units. The closest contacts between the chains are determined by Au ∙∙∙ I and I ∙∙∙ I interactions of the central P-Au-I unit.

Single-crystal EPR investigations on the paramagnetic Cu II impurity present in the binuclear antiferromagnetically coupled complex (n-Bu 4 N) 2 [(dmit)Cu II (tto)Cu II ,(dmit)] (dmit = dimercaptoisotrithion, tto = tetrathiooxalate) identify the mononuclear S =½ complex [Cu II (dmit) 2 ] 2− as being responsible for the observed EPR spectra. The 63 Cu hyperfine structure data as well as the data obtained from density functional theory (DFT) and extended Hückel theory molecular orbital (EHT-MO) calculations were used to characterize the spin-density distribution of the copper complex.

Reactions of [Cp 2 WH 2 ] with B(C 6 F 5 ) 3 and Me 2 NB(CF 3 ) 2 , respectively, leads to the formation of the zwitterions [CpWH 3 {η 5 -C 5 H 4 B(C 6 F 5 ) 3 }] (1) and [CpWH 2 {η 5 -C 5 H 4 B(NHMe 2 )(CF 3 ) 2 }] (2). [Cp * 2 WH 2 ] reacts with B(C 6 F 5 ) 3 and tBuBCl 2 to give the saltlike compounds [Cp * 2 WH 3 ][B(C 6 F 5 ) 4 ] (3) and [Cp * 2 WH 3 ][tBuBCl 3 ] (4).

The crystal structure of [Ni(NH 3 ) 6 ]SO 4 has been determined by single-crystal X-ray diffraction (P2 1 /c; Z = 4; a = 705.0(1), b = 1195.2(2), c = 1180.0(2) pm, β = 96.14(3)°; 2271 reflections; R 1 = 3.94%). In the hitherto unknown structure type, both the [Ni(NH 3 ) 6 ] 2+ and the SO 4 2- ions form chains along [100], The six crystallographically different ammine ligands of the distorted [Ni(NH 3 ) 6 ] 2+ octahedra are involved in hydrogen bonds to six crystallographically equivalent SO 4 2- ions (site symmetry C 1 ). The strength of the hydrogen bonds differs strongly (ν OD of matrix isolated NH 2 D molecules: 2378 - 2494 cm -1 , N ∙∙∙ O distances: 272 - 340 pm). The temperature evolution of the IR bands reveals the decrease of the dynamic orientational disorder of the NH 3 molecules with decreasing temperature.

Starting from ethyl 2,4-dioxo-4-ferrocenyl-butanoate (1) a series of new ferrocene derivatives has been prepared. While the reaction with o-phenylene diamine leads to two ferrocene-containing heterocyclic compounds, 4-ferrocenyl-3H-1,5-benzodiazepine-2-carbonic acid ethyl ester (3) and 3-(2-ferrocenyl-2-oxo-ethylidene)-3,4-dihydro-1H-quinoxalin-2-one · H 2 0 (4), reactions with m- and p-phenylene diamine give both the mono- and disubstituted products 5 - 8, respectively. The conversion of 4 by Lawesson’s reagent results in 2-ferrocenvl-thieno[2,3- b]quinoxaline (9). The new compounds have been characterized by their 1 H, 13 C NMR, and mass spectra. The molecular structures of 4-ferrocenyl-4-oxo-2-phenylamino-but-2-enoic acid ethyl ester 2, and of 4 and 9 have been determined by X-ray crystal structure analysis.

The synthesis, IR and 31 P NMR spectra of the complexes of various N-aryltriphenylphosphinimines with some mercury dihalides as well as the corresponding phosphonium salts are reported. It is shown by an X-ray crystal structure analysis of the complex of the unsubstituted phosphinimine with HgCl 2 that in the solid state these complexes form dimers via two Hg ∙∙∙ μ 2 - Cl ∙∙∙ Hg bridges.

The stannides LnRu 4 Sn 6 (Ln = La, Pr, Nd, Sm, Gd) were prepared by reaction of the elements in an arc-melting furnace and subsequent annealing at 1120 K. The praseodymium, the neodymium, and the samarium stannide were obtained for the first time. The LnRu 4 Sn 6 stannides were investigated by X-ray diffraction both on powders and single crystals. They adopt the YRu 4 Sn 6 type structure which was refined from single crystal X-ray data for the samarium and the gadolinium compound: I4̄2m, a = 686.1 (1), c = 977.7(2) pm, wR2 = 0.0649, 483 F 2 values for SmRu 4 Sn 6 , and a = 685.2(1), c = 977.6(3) pm, wR2 = 0.0629, 554 F 2 values for GdRu 4 Sn 6 with 19 variables for each refinement. The striking structural motif of these stannides are distorted RuSn 6 octahedra with Ru-Sn distances ranging from 257 to 278 pm. Four of such octahedra are condensed via common edges and faces forming [Ru 4 Sn 6 ] units which are packed in a tetragonal body-centered arrangement. The rare-earth atoms fill the voids between the [Ru 4 Sn 6 ] units. Based on an extended Hückel calculation, strong bonding interactions were found for the Ru-Sn and the various Sn-Sn contacts.

The results of a Rietveld refinement of CsMnCr(CN) 6 · D 2 O neutron powder data (a = 1084.3(1) pm, F4̄3m, Z = 4) and of a neutron single crystal structure refinement of tetragonal NMe 4 Mn II (Cr 0,06 Mn 0,94 ) III (CN) 6 · 8 H 2 O (a = 1065.8(21), c = 1064.6(26) pm, P4/n, Z = 2) at ambient temperature are reported. Single crystal X-ray analyses of the isostructural octahydrate NMe 4 MnCo(CN) 6 · 8 H 2 0 (a = 1062.1 (1), c = 1046.2( 1) pm) and of gel-grown crystals of cubic Mn 3 II [Mn III (CN) 6 ] 2 - 15 H 2 O (a = 1062.6(3) pm, Fm3̄m, Z = 4/3) and Cd 3 [Fe(CN) 6 ] 2 · 15 H 2 O (a = 1067.7(3) pm) were performed as well. The latter “Prussian Blues” are highly disordered and intermediate with respect to cyano-bridging between the above three-dimensional cesium and one-dimensional tetramethylammonium compounds.

The black, air and moisture sensitive octastannanediide R * 6 Sn 8 [Na(THF) 2 ] 2 (4) (R* = SitBu 3 ) is prepared by reaction of Sn[N(SiMe 3 ) 2 ] 2 with R*Na in tBuOMe at -78°C. Red brown octastannane R* 6 Sn 8 (5) is formed by thermolysis of the tristannacyclopropene R* 4 Sn 3 in benzene at 100 °C. According to the result of the X-ray structural analysis, 4 contains a Sn 8 cubane with six Sn atoms each connected with R* and two at the end of a space diagonal connected with Na(THF) 2 . A preliminary X-ray structure analysis shows 5 to adopt the same Sn 8 cubane structure as 4 with two bare Sn atoms at the end of a space diagonal.

Ligand exchange reactions of NiCl 2 (PPh 3 ) 2 with O (S )⌒N⌒S ligands were studied. Oxidation products of O⌒N⌒S ligands have been characterized and their structures determined: 3-methyl-4H-benzo[b] [ 1,4]thiazin-2-yl-phenylmethanone / 2-methyl-benzo[d] [ 1,3]thiazole (mixed crystal); [2-iminoisopropyl-thiophenolato(2-)](triphenyl-phosphane)-nickel(II); 1 -phenyl-3-methyl-4-(benzoyl-thiobenzoylhydrazono)-pyrazol-5-thione; [ 1 -phenyl-3-methyl- 4-(benzoyl-thiobenzoylhydrazono)-pyrazol-5-thionato](triphenyl-phosphane)-nickel(II).

K[B 6 PO 10 (OH) 4 ] was prepared under mild hydrothermal conditions (T = 170 °C) from a concentrated solution of K 2 B 4 O 7 ∙ 4H 2 O , KH 2 PO 4 , and HCl (18%). The crystal structure of the tetragonal compound was solved by X-ray single crystal methods (space group P 4/ncc, No 130): a = 1209.66(13), c = 759.05(7) pm; Z = 4. The anionic partial structure consists of infinite rods of ∞ 1 [B 6 PO 10 (OH)4] − which are built of vierer-rings of alternating BO 4 and PO 4 tetrahedra with additional open-loop branchings via planar B 2 O 3 (OH ) 2 groups at the BO 4 units by sharing common oxygen functions. Potassium (K + ) is located within structural channels running along [001]; the eightfold coordination by oxygen (OH-groups) results in a (slightly) distorted tetragonal antiprism.

The diamagnetic halfsandwich complexes [V(η 7 -C 7 H 7 )(CO) 3 ] and [V(η 5 -L 5 )(CO) 4 ] have been used as intermediates in the conversion of hexcarbonylvanadium, V(CO) 6 , to the paramagnetic trovacene derivatives, [V(η 5 -L 5 )(η 7 -C 7 H 7 )] [L 5 = cyclopentadienyl ligand, C 5 H 4 -R (R = H (1), Me (1a), t Bu (1b)) and C 5 Me 5 (1c); indenyl (2) and 2-methylindenyl (2a)]. The molecular structure of 2a has been determined: the distances between vanadium and the center Z of the (nearly parallel) ring ligands are 193.0 pm (V-Z 5 ) and 146.2 pm (V-Z 7 ).

Silver(I) cyanoximate complexes Ag{ONC(CN)-R} (R = COPh, {L 1 }; COC(CH 3 ) 3 , {L 2 }; benzothiazol-2-yl, {L 3 }) with triphenylphosphine and -stibine of compositions Ag(PPh 3 ) n {L} (n = 2, 4) and Ag(SbPh 3 ) n {L} (n = 3 for {L 1 } and {L 2 }, n = 2 for {L 3 }) were synthesized by the reaction of the components in acetonitrile solution and characterized by elemental analyses and IR spectroscopy. The crystal structures of Ag(SbPh 3 ) 3 {L} (L = {L 1 } (1), {L 2 } (2), Ag(SbPh 3 ) 2 {L 3 } ∙ CH 3 CN (3) and Ag(PPh 3 ) 2 {L 1 } ∙ CH 3 CN (4), have been determined by X-ray diffraction. For all the compounds examined the coordination environment of the silver atom has the geometry of a distorted terahedron ([AgP 2 NO] (4); [AgSb 3 N] (1), (2); [AgSb 2 N 2 ] (3)). The bis adducts Ag(EPh 3 ) n {L} adopt molecular structures, in which the organic anions are coordinated in bidentate chelate fashion via the nitroso nitrogen atom and the oxygen (nitrogen for {L 3 }) atom of the substituent R. In the tris-stibino complexes (Ag-Sb 2.670(4) - 2.7748(8) Å; Sb-Ag-Sb 108.87(4) - 115.00(2)°) the cyanoximates are unidentate ligands and coordinated via the nitroso nitrogen atoms (Ag-N ca. 2.35(1) Å). The different behaviour of N ,O and N,N chelating cyanoximes under the same conditions suggests, that the Sb donor triphenylstibine is able to substitute the oxygen atoms in the silver(I) coordination sphere, but not the nitrogen ones. This causes the formation of 1:3 adducts of Ag{L} with SbPh 3 for N ,O donors {L 1 } and {L 2 }, and only 1:2 for N,N donor anionic {L 3 }.

2-Methylpapaverinium iodide (1) reacted with hydroxylamine to papaverine-N-oxide (2), but without a detectable intermediate and only in moderate yield, caused by the steric hindrance of the 1-substituent. The ring opened product of 2-dinitrophenylisoquinolinium salt with hydroxylamine, the enamine-oxime 3b gave rise to a 3-substituted cyclic nitrone (6), when heated with triethylamine. This alkali-stable compound was transformed with acid quantitatively to isoquinoline-N-oxide (4). The enaminonitrile 9c, treated with triethylamine showed cyclization to the iminoisoquinoline 10, which by loss of nitrous acid produced the tetracyclic azaindole 11. The 2-methoxyisoquinolinium salt 16 was cleaved with O-methylhydroxylamine to the resistant di(O-methyloximes) (20a/b), unable to form the amine oxide 4. From these and former results, a mechanism for the ring opening of cycliminium salts and the recyclization to amine oxides was proposed.

Oxazolone (1) couples with aromatic diazonium salts to yield the arylhydrazones (3a-c). Compound 3 reacts with aniline to give aryl hydrazone (5). Compound 5 was also obtained via converting 1 into the imidazolone (4) and subsequent treatment of 4 with aromatic diazonium salts. Compounds 1 and 12 reacted with arylidenemalononitrile (6) to yield compounds 8 and 14 respectively. Also compounds 1, 12 condensed with an aromatic aldehydes to yield 11 and 17. Compounds 11, 17 reacted further with one molecule of malononitrile to give compounds 8 and 14, respectively. Compound 20 which was generated in situ by heating phenacylthiocyanate (19) in acetic anhydride on treatment with hydrazine hydrate or phenyl hydrazine gives 21 and 22 respectively. A lso 20 reacted with malononitrile or with ethyl cyanoacetate to give 23 and 24, respectively.

The electronic and molecular structure of 2,6-bis{N-(2-hydroxyphenyl)iminomethyl}-4- methylphenol (hpimp) is clarified from the measurements of electronic absorption and 1 H NMR spectra in various solvents and an X-ray diffraction analysis, together with MO calculations. Electronic absorption bands of hpimp are at 422, 397.9, 359, 341, 294.3, 265.8, and 224 nm in the non-polar solvent cyclohexane. In polar solvents, such as methanol, an additional band which is assigned to a partly formed keto-amine hpimp, is observed at 499 nm. From the 1 H NMR spectra it is seen that hpimp exists in the enol-imine form in non-polar solvents, and as an equilibrium mixture of enol-imine and keto-amine forms in polar solvents. Each electronic absorption band of solid hpimp in a KBr disk is broadened compared with the solution state, and an additional band, again assigned to the keto-amine form, appears around 499 nm. An X-ray diffraction analysis shows that hpimp assumes a keto-amine structure in the solid state, and forms a column structure along the c-axis. MO calculations suggest that the enol-imine hpimp has a twist structure around the two C−C single bonds, the twist angle being 100° to 120°.

The methanolic extract of Stocksia brahuica yielded two new aromatic constituents: diphenylacetic acid and brahene (2',4'-dihydroxy-7-methoxy-4,5-methylenedioxyisoflavene). Their structures were characterized with the help of modern spectroscopic techniques including 2D-NMR.

A comparative crystallographic analysis of the conformation of porphyrin diacids with various substituent types reveals considerable differences in the degree of nonplanarity and distortion modes. Diacids of 5,10,15,20-tetraarylporphyrins generally exhibit typical saddledistorted macrocycles with displacements of the C b positions in the range of 0.7-1.0 Å. Adding peripheral substituents, i.e., using dodecasubstituted porphyrins for the diacid formation yields similar distortion types albeit with larger out-of-plane displacements. As a result of the combined effect of both peripheral (interaction between the C b and C m substituents) and core (interaction between the four inner hydrogen atoms) steric strain the maximum C b displacements reach 1.3-1.5 Å. Quite a different situation is observed for the diacids of 2,3,7,8,12,13,17,18-octaalkylporphyrins. Here, macrocycles with pair-wise displacement of neighboring pyrrole rings and significant NH pyramidalization and those with classic saddle distortion are found. Generally, octa- β-substituted porphyrin diacids show smaller degrees of nonplanarity; C b displacements ranged from 0.06 to 0.72 Å. On the basis of the overall degree of conformational distortion (⊿24 = average deviation of the 24 macrocycles atoms from the mean plane), the three different types of porphyrin macrocycles studied differ considerably in their degree of conformational flexibility. For several porphyrin crystal structures with different counterions and/or solvate molecules were obtained. Taking into account results from the literature 2,3,7,8,12,13,17,18-octaethyl-22,24-dihydro-5,10,15.,20-tetraphenylporphyrin (13) shows the smallest degree of flexibility (⊿24 = 0.61-0.63 Å; four different X-ray structures), while 22,24-dihydro-5,10,15,20-tetraphenylporphyrin (1) is more flexible (Z⊿24 = 0.42-0.52 Å; four structures). The largest flexibility is observed for 2,3,7,8,12,13,18-octaethyl- 22,24-dihydroporphyrin (7) (⊿24 = 0.02-0.33 Å; four structures).

The preparation and characterization of three homologous actinidocenes of the composition An[η 8 -C 8 H 5 (SiMe 3 ) 3 -1,3,5] 2 (An = Th (1), U (2), Np (3)) is reported. Due to the presence of six trimethylsilyl groups these sandwich complexes are quite volatile and soluble in non-polar organic solvents.