Volume 57, Issue 7

Four donor/acceptor complexes between halide anion donors and the tetraiodoethene acceptor molecule with tetra(n-butyl)ammoniumcountercations, {(H 9 C 4 ) 4 N ⊕ X ⊖ ···I 2 C=CI 2 )} (X ⊖ = Cl ⊖ , Br ⊖ , I ⊖ , SCN ⊖ ) could be crystallized from acetone solutions of the components R 4 N ⊕ X ⊖ and I 2 C=CI 2 by using low gradient techniques, and their structures determined at low temperature. Their molecule packing motif are layers of halide anion/tetraiodoethene patterns, which are penetrated by one of the four R 4 N ⊕ n-butyl chains. The structure comparison, including analogous ones from an extensive Cambridge Structural Database search, discusses the geminal or vicinal addition to dimer subunits {X ⊖ ···I 2 C=CI 2 } 2 as well as their ribbon formation via additional contacts X ⊖ ···I, and the effects of the voluminous R 4 N ⊕ countercations. Altogether some light is shedded on essential facets of the fascinating self-assembly comprising an electron-rich halide anion and a polyiodo acceptor molecule.

Syntheses of the homoleptic trimethylsilanolato complexes V(OSiMe 3 ) 3 and V(OSiMe 3 ) 4 are described. The thiovanadium(V)compound VS(OSiPh 3 ) 3 (11) is formed from [V(OSiPh 3 ) 3 - (THF) 2 ] upon oxidation with elemental sulfur; 11 has been characterized by 51 V NMR spectroscopy.

1,1,2,2-Tetraphenyldisilane-1,2-diol (3) was prepared in a two-step synthesis, starting from 1,2-bis(diethylamino)-1,1,2,2-tetraphenyldisilane (1). Treatment of 1 with acetyl chloride yielded 1,2-dichloro-1,1,2,2-tetraphenyldisilane (2), which upon hydrolysis gave 3 (total yield 83%). Compounds 2 and 3 were characterized by elemental analyses (C,H) and solution NMR experiments ( 1 H, 13 C, 29 Si; CDCl 3 ). In addition, compound 1 and its condensation product, 1,5-dihydroxy-1,1,2,2,4,4,5,5-octaphenyl-3-oxa-1,2,4,5-tetrasilapentane (4; studied as the hemibenzene solvate 4ּ1/2C 6 H 6 ), were structurally characterized by single-crystal X-ray diffraction.

A new cyano-bridged 1D polymeric linear chain complex {[Y(phen) 2 (H 2 O) 2 Fe(CN) 6 ]ּ 8H 2 O} n (where phen = 1,10-phenanthroline) has been synthesised and its crystal structure determined. The yttrium(III) and iron(III) centres achieve distorted square antiprismatic and slightly distorted octahedral geometry, respectively. Presence of an extensive network of hydrogen bonds present in the complex impart the overall stability to the system. The presence of ten water molecules per molecular unit has been confirmed by thermogravimetric analysis.

Diethynyl(dimethyl)silane, Me 2 Si(C≡C-H) 2 2, reacts with triethylborane, Et 3 B 1, by 1,1- ethylboration to give a silole, 3-diethylboryl-4-ethyl-1,1-dimethyl-sila-2,4-cyclopentadiene 3, as a short-lived intermediate which reacts further with 2 or dimerises via [4+2]cycloadditions to the 7-silanorbornadiene 4 or the 7-silanorbornene derivatives 5, respectively. Since the silole 3 was not detected by NMR, the analogous reactions were studied using 1-alkynyl(ethynyl)- dimethylsilanes, Me 2 Si(C≡C-H)C≡C-R 6 [R = Bu (a), i Pent (b), t Bu (c)]. In these cases, 1,1-ethylboration gave the siloles 7a,b,c and 7'a,b, now detected in the reaction solutions, and also 7-silanorbornadienes as [4+2]cycloaddition products. Major products were identified, and the progress of the reactions was monitored by NMR spectroscopy ( 1 H, 11 B, 13 C and 29 Si NMR).

Iron(III) coordination compounds of the general formula FeL 3 (where L 1 = {CCl 3 C(O)NP(O)-[N(C 2 H 5 ) 2 ] 2 - }-N,N'-tetraethyl-N''-trichloroacetylphosphorictriamide anion, and L 2 = {CCl 3 - C(O)NP(O)[N(CH 2 CH 2 ) 2 O] 2 } - -dimorpholido-N-trichloroacetylphosphoricamide anion) have been synthesized and characterized by means of IR, UV-VIS, ESR spectroscopy, and X-ray analysis. The complexes have a molecular structure with the phosphoryl ligands coordinated to the metal ioninabidentatemanner via phosphoryl and carbonyl oxygen atomswith formation of six membered chelate rings. The coordination around the Fe(III) atoms is distorted octahedral, to give fac-isomers in both structures.

Platinum-containing groups and porphyrins in the same molecule not only show additivity of the dark toxicity of the platinum moiety and the phototoxicity of the porphyrin system but also a selective enrichment of porphyrin platinum conjugates in tumor tissues compared to platinum-only drugs. Porphyrin platinum conjugates containing amino-porphyrin non-leaving groups and porphyrin-carboxylate leaving groups were synthesized and tested with the mammary carcinoma cell line MDA-MB-231.

A novel route to reactive In(I)-complexes [{(CO) 5 M}InXּTHF] (M = Cr, X = Cl, Br; M = Mo, X = Cl; M = Mo, X = Cl) is described. With an excess of tetraphenylphosphonium halides [Ph 4 P]X (X = Cl, Br) these compounds react to give trihaloindate-complexes [Ph 4 P] 2 ּ [{(CO) 5 M}InX 3 ] (M = Cr, X = Cl: 1a, X = Br: 1b; M = Mo, X = Cl: 2; M = W, X = Cl: 3), which contain indium in a formal oxidation state of +I. The reaction of equimolar ammounts of [{(CO) 5 Cr}InBrּTHF] and bromide ions gives the bridged, dinuclear compound [{(CO) 5 Cr}InBr(μ 2 -Br)] 2 2- (4). 4 is an intermediate in the reaction of [{(CO) 5 Cr}InBrּTHF] to [{(CO) 5 Cr}InBr 3 ] 2- , 1b. Reaction of sodium-8-hydoxychinolate and [{(CO) 5 Cr}InClּTHF] produces the anion [{(CO) 5 Cr}In(oxinat) 2 ] - (5) which contains In(+I) in a square pyramidal coordination geometry. [{(CO) 5 Cr}GeI 3 ] - , which is isoelectronic to 1-3, reacts with 8-hydroxyquinoline to produce [{(CO) 5 Cr}Ge(oxinat) 2 ] (6) which is isoelectronic to 5. All new compounds have been characterized by X-ray analysis and by the usual analytic and spectroscopic techniques. 115 In NMR spectra of M(CO) 5 substituted indium species (M = Cr, Mo, W) are reported for the first time.

Two new tetrakisη 2 -pyrazolato) zirconium complexes are prepared from the reaction of Zr(CH 2 Ph) 4 with bulky pyrazolate ligands bearing indenylmethyl (HL 1 ) or fluorenylmethyl (HL 2 ) substituents, respectively. Zr(L 2 ) 4 has been analyzed by X-ray crystallography, which represents the first structural characterisation of a homoleptic η 2 -pyrazolato zirconium compound.

As a sequel to prior reports on strong and weak hydrogen bonding in onium di(methanesulfonyl) amide crystals, low-temperature X-ray structures are described for three salts of general formula BH + (MeSO 2 ) 2 N - , where BH + is 2,2΄-bipyridinium (1; monoclinic, space group P2 1 /n, Z΄ = 1), 1,10-phenanthrolinium (2; monoclinic, P2 1 /c, Z΄ = 2), or 1,8-bis(dimethylamino) naphthalinium (3; orthorhombic, P2 1 2 1 2 1 , Z΄ = 1). Monoprotonation of the organic bases by (MeSO 2 ) 2 NH results in the formation of an intra-cation N-H···N hydrogen bond, which is asymmetric in 1 and 2, but approximately symmetric in the proton-sponge cation of 3. Moreover, the acidic H atom is engaged in a cation-anion contact N-H···N - in 1 and 2 or H + ···O δ- in 3, thus conferring three-centre character upon the strong hydrogen bonding. Each structure displays a multitude of close interionic C-H···O/N contacts that are geometrically consistent with weak hydrogen bonding. A salient feature is provided by short S-CH 2- H···O-S inter-anion contacts, which lead to layers in 1 and to catemers in 2, but are non-existent in structure 3. The cations of both 1 and 2 form π-stacks that are intercalated between the anion layers or surrounded by six anion catemers, whereas in structure 3 each cation is octahedrally coordinated by six anions and vice-versa. The heteroionic connectivity comprises the aforementioned branches of the strong three-centre hydrogen bonds (in 1-3), numerous Car-H···A bonds (1, 2: A = O; 3: A = O, N), S-CH 2 -H···N ring interactions (1, 2), and close N-CH 2 -H···O=S contacts (3; possibly destabilizing).

Single crystals of the ternary indide CeNiIn 2 were synthesized from an indium flux. An arc-melted button of the starting composition CeNiIn 2 was annealed in a zirconia crucible with a slight excess of indium at 1200 K followed by slow cooling (5 K/h) to 870 K. The new indide has been investigated by X-ray diffraction on powders and single crystals: PrNiIn 2 type, Cmcm, a = 440.78(4), b = 1834.3(1), c = 2178.8(2) pm, wR2= 0.0753 for 1471 F 2 values and 66 variable parameters. The structure contains three crystallographically independent nickel positions which have a distorted trigonal prismatic coordination. The CeNiIn 2 structure is related to the MgCuAl 2 structure by chemical twinning. The shortest interatomic distances occur for Ni-In and In-In contacts. The nickel and indium atoms form a complex three-dimensional [NiIn 2 ] network in which the cerium atoms fill distorted pentagonal channels. Magnetic susceptibility measurements indicate Curie-Weiss behavior with an experimental magnetic moment of 2.44(3) μ B /Ce atom. At 3.4(3) K CeNiIn 2 orders ferro- or ferrimagnetically. The experimental saturation magnetization at 2K and 5.5 T is 0.95(2) μ B /Ce.

The ternary indides LnRhIn 2 (Ln = La, Ce, Pr, Nd, Sm) were synthesized by arc-melting of the elements under an argon atmosphere and subsequent annealing at 870 K. The samples have been investigated by X-ray diffraction on powders and single crystals: MgCuAl 2 type, Cmcm, a = 448.2(1), b = 1025.7(1), c = 795.1(1) pm, wR2 = 0.0372, 228 F 2 values, 16 variables for LaRhIn 2 , a = 446.0(1), b = 1017.3(2), c = 792.7(1) pm for CeRhIn 2 , a = 444.03(6), b = 1013.1(1), c = 792.5(1) pm for PrRhIn 2 , a = 442.49(5), b = 1012.7(1), c = 789.3(1) pm for NdRhIn 2 , and a = 438.1(1), b = 1009.3(1), c = 788.3(1) pm, wR2= 0.0414, 304 F 2 values, 16 variables for SmRhIn 2 . Geometrical motifs of these structures are tricapped trigonal prisms around the rhodium atoms. The shortest interatomic distances were observed for the Rh-In contacts: 280-282 pm for LaRhIn 2 and 276-279 pm for SmRhIn 2 . Together, the rhodium and indium atoms build a three-dimensional [RhIn 2 ] polyanion in which the lanthanoid atoms fill distorted pentagonal channels. According to one short La-Rh (282 pm) and Sm-Rh (284 pm) distance one can assume strong bonding of the lanthanoid atoms to the polyanion.

Palladium complexes of two different P,N ligands (a phosphane-pyridine and a phosphane-imine ligand) were synthesized and characterized. Single crystal X-ray structure analyses of the palladium diiodide compounds revealed a square-planar coordination geometry at the metal center with a longer Pd-I bond in trans-position to the phosphorus atom. The chloro-methyl palladium species of the phosphane-pyridine ligand was applied for the oligomerization of ethene using a borate salt as cocatalyst.

The reactions of [(η 3 -C 3 H 5 ) 2 Rh-μ-Cl] 2 with the anions of α-amino acids (glycine, L-alanine, L-valine, L-isoleucine, L-proline, L-phenylalanine, L-phenylglycine, L-thyrosine) afford the N,O-chelates (η 3 -C 3 H 5 ) 2 Rh(α-amino carboxylate). For complex (η 3 -C 3 H 5 ) 2 Rh(glycinate) dynamic behaviour in solution could be observed by 1 H NMR. The structure of (η 3 -C 3 H 5 ) 2 Rh(L-prolinate) was determined by X-ray diffraction.

Mummification salts and mummified bones were assayed for borate. In two samples of mummification salt one from Deir el-Bahari (26 th Dynasty, 700-600 BC) and salt from the embalming material of Tutankhamen (18 th Dynasty, 1370-1335 BC) 3.9 and 2.1 μMol borate/ gram were found, respectively. Six mummified bone fragments from the Old Kingdom contained up to 1.2 μMol/gram. It is suggested that borate containing salt was used during mummification. The reactivity of borate on bone alkaline phosphatase, which is known to survive mummification for more than 4000 years, was examined. Borate forms high relative molecular mass adducts of this enzyme being temperature resistant and functionally distinct.

The marine Streptomycete isolates B5342 and B5525 forms, beside large amounts of the antitumor antibiotic chartreusin (1a), two chartreusin monoacetates as trace components. Whereas the chemical shift of the acetate methyl in 1c is in the normal range, the methyl group of the 2"-acetate residue in 1b and also in the tetra- and pentaacetates shows an extreme upfield shift. The structures of the monoacetates were confirmed by extensive NMR experiments, the anisotropic shift is explained by semi-empirical calculations.

Substitution of the Cl atoms of CH 2 (AlCl 2 ) 2 by 2,2,6,6-tetramethylpiperidino or bis(trimethylsilyl)- amino groups leads to monomeric methylene bis(diaminoalanes). These show a wide Al-C-Al bond angle as determined by X-ray crystallography and asymmetrically bonded amino groups in the piperidino derivative.