Ernst Horn

Dibutyltin perfluoroalkanecarboxylates: synthesis, NMR characterization and in vitro antitumour activity

Three dibutyltin perfluoroalkanecarboxylates have been synthesized, characterized by H-1-, C-13-, F-19- and Sn-117-NMR, Mossbauer, IR and mass spectroscopy. The structure of tetra-n-butylbis(trifluoroacetato)distannoxane has been elucidated by X-ray crystallography. The in vitro antitumour activity of the three compounds against seven human tumour cell lines was found to be as high as or even higher than that for reference compounds used clinically

SELF-ASSEMBLY OF A RADIALLY FUNCTIONALIZED HEXAGONAL MOLECULE : HEXAKIS(4-HYDROXYPHENYL)BENZENE

Two different porous hydrogen-bonded networks are formed by self-assembly of the radially substituted host 1. In the network of type A, formed by 1 small middle dot4 Et(2)O, all OH groups of 1 are involved in hydrogen bonding, and the molecular sheets are stacked without translation to generate extended channels that accommodate the Et(2)O molecules. Four OH groups of 1 are involved in the type B network of 1 small middle dot4 DMF, and lateral translation of the sheets in an ABAB sequence generates large chambers, each of which contains four DMF molecules.

Two-dimensional hexagonal hydrogen-bonded network with triangle-like large cavities: hexakis(4-carboxyphenyl)benzene

Hexakis(4-carboxyphenyl)benzene (1) as a radially functionalized hexagonal host was synthesized by the Co-catalyzed cyclotrimerization of diarylacetylene. When recrystallized from MeOH, host 1 self-assembles into a two-dimensional hexagonal hydrogen-bonded network having triangle-like large cavities (one side of ca. 15.2 A), each of which is filled with guest molecules without interpenetration of the crystal lattice.

Synthesis and spectroscopic studies of diorganotin derivatives with tolfenamic acid. Crystal and molecular structure of the first complex of tolfenamic acid, 1,2:3,4-di-μ2-2-[(3-chloro-2-methylphenyl)amino]-benzoato-O,O-1,3-bis-2-[(3-chloro-2-methylphenyl)amino]benzoato-O-1,2,4:2,3,4-di-μ3-oxo-tetrakis[di-n-butyltin(IV)]

Abstract The complexes [Me2LSnOSnLMe2]2 (1) [Bu2LSnOSnLBu2]2 (2) and Bu2SnL2.H2O (3), where HL is 2-[bis(3-chloro-2-methylphenyl)amino]benzoic acid (tolfenamic acid), have been prepared and characterized structurally by means of 19Sn Mossbauer, vibrational and 1H- and 13C-NMR spectroscopies. The crystal structure of complex 2 has been determined by X-ray crystallography. Three distannoxane rings are present to the dimeric tetraorganodistannoxanes of planar ladder arrangement with distorted trigonal-bipyramidal geometry about the five-coordinated tin centers. The structure, which has twofold symmetry, features a central Sn2O2 unit with two additional tin atoms linked at O. Pairs of tin atoms are bridged by bidentate carboxylate ligands and the external tin atoms have their coordination geometry completed by a monodentate carboxylate ligand. The tin atom geometries are similar and are based on a trigonal bipyramidal arrangement. Significant π→π stacking, C–H–π interactions and intrarmolecular hydrogen bonds stabilize this structure. The polar imino hydrogen atom on N(1) and N(2) participate in a bifurcate intramolecular hydrogen bond. In this case complex 2 is self-assembled via C–H–π and π→π stacking interactions. Tin-119 Mossbauer, vibrational and NMR data are discussed in terms of the crystal structure and the proposed structures for 1 and 3. From the variable-temperature Mossbauer effect, the Debye temperatures for 1–3 were determined.

Cluster chemistry. LI: Reactions of some substituted ruthenium and osmium cluster carbonyls with dihydrogen. X-ray crystal structures of Ru3(μ-H)2(μ3-PPh)(CO)8(PMePh2), Ru4(μ-H)4(μ-dppm)(CO)10, Ru4(μ-H)3(μ3-PPhCH2PPh2(CO)10 and Os3(μ-H)2(μ-dppm)(CO)8

Summary The reactions of dihydrogen (80°C, 20 bar, 2 h) with a series of tertiary phosphine and phosphite complexes Ru 3 (CO) 12- n (L) n (L) = PMe 3 , PPh 3 , PPh (OMe) 2 or P(OMe) 3 ; n = 1–3), and with complexes containing dppm, dppe, dpam and PPh 2 (C 6 H 4 CH=CH 2 -2) have been studied. Complexes containing monodentate ligands gave tetranuclear complexes Ru 4 (μ-H) 4 (CO) 12- n (L) n ( n = 0–3, but not 4), whereas complexes with bidentate ligands showed varying behaviour. Thus Ru 3 (μ-dppm)(CO) 10 gave Ru 3 (μ-H) 2 (μ 3 -PPhCH 2 PPh 2 )(CO) 9 , further hydrogenation of which afforded Ru 3 (μ-H) 2 (μ 3 -PPh)(CO) 8 (PMePh 2 ). Ru 3 (μ-dppe)(CO) 10 gave a mixture of Ru 3 (μ-H)(μ 3 -PPhCH 2 CH 2 PPh 2 )(CO) 9 and Ru 4 (μ-H) 4 (μ-dppe)(CO) 10 as the major products, and Ru 3 (μ-η 2 , P -CH 2 =CHC 6 H 4 PPh 2 )(CO) 10 gave a mixture of Ru 4 (μ-H) 4 (CO) 12 - n PPh 2 (C 6 H 4 Et-2) n ( n = 0 and 1). Pyrolysis of Ru 4 (μ-H) 4 (μ-dppm)(CO) 10 afforded Ru 4 (μ-H) 3 (μ 3 -PPhCH 2 PPh 2 )(μ-CO) 2 (CO) 8 . The molecular structures of Ru 3 (μ-H) 2 (μ 3 -PPh)(CO) 8 (PMePh 2 ), Ru 4 (μ-H) 4 )(μ-dppm)(CO) 10 and Ru 4 (μ-H) 3 (μ 3 -PPhCH 2 PPh 2 )(μ-CO) 2 (CO) 8 have been determined: 2286, 4930 and 6393 data ( I ≽ 2.5σ( I )) were refined to R and R w values of 0.032 and 0.037, 0.026 and 0.035, and 0.043 and 0.053, respectively. Hydrogenation of Os 3 (μ-dppm)(CO) 10 gave Os 3 (μ-H) 2 (μ-dppm)(CO) 8 , whose structure was also determined: 3367 data with I ≽ 2.5 σ( I ) were refined to R w 0.052.

Cluster chemistry: LXXXII. Reactions between Ru3(μ-dppm)(CO)10 and 1-alkynes and related chemistry. Crystal structures of Ru3(μ-H)(μ3-C2C6F5)(μ-dppm)(CO)7, Ru3{μ3-PPhCH2PPh(C6H4))}(μ-C4H2Ph2)(CO)6, AuRu3(μ3-C2Ph)(μ-dppm)(CO)7{P(C6H4Me-p)3} and Ru2(μ-I)(μ-dppm)(μ-C2Ph)(CO)4

Abstract Reactions between Ru3(μ-dppm)(CO)10 (1) and 1-alkynes, HC2R (R = Ph, tBu, SiMe3, C6F5), have given 75–90% yields of Ru3(μ-H)(μ3-C2R)(μ-dppm)(CO)7 (3–6); the related complexes Ru3(μ-H)(μ3C2Ph)(μ-dppm)(CO)6(PPh3) and Ru3(μ-H)(μ3-C2Ph)(μ-dpam)(CO)7 have also been obtained, while addition of Au(C2Ph)(PR3) to 1 gave AuRu3(μ3-C2Ph)(μ-dppm)(CO)7(PR3) (R = Ph, 10; C6H4Me-p, 11). A reaction between Ru3(μ3-PPhCH2PPh(C6H4)(CO)9 and HC2Ph afforded Ru3{μ3-PPhCH2PPh(C6H4)}(μ-C4H2Ph2)(CO)6 (9), containing a metallacyclopentadiene unit. The complex Ru2(μ-I)(μ-dppm)(μ-C2Ph)(CO)4 (12) was obtained by treating 3 with I2. The molecular structures of 6, 9, 11 and 12 were determined by single-crystal X-ray studies.

Preparation and conformational analysis of 6,10-disubstituted [1,2,3]trithiolo[h]benzopentathiepin monooxides

6,10-Diethyl[1,2,3]trithiolo[ h ]benzopentathiepin was oxidized with m CPBA (1 eq.) to produce four monooxides, 6,10-diethyl[1,2,3]trithiolo[ h ]benzopentathiepin 8-oxides and 6,10-diethyl[1,2,3]trithiolo[ h ]benzopentathiepin 7-oxides. The structure of the four monooxides obtained was determined by X-ray crystallography. The activation parameters, ΔG ≠ , ΔH ≠ , and ΔS ≠ of these compounds with respect to the inversion of their pentathiepin rings were determined by the results of 1 H-NMR spectroscopy.

Nucleophilic Addition of Telluroxides to a Cationic Ditelluroxane: Oligotelluroxanes

Tellurane oligomers with oxo bridges, namely, the oligotelluroxanes 3, were prepared from the cationic ditelluroxane 1 and the telluroxide 2. The reactivity of 3 depends on the cationic character of the terminal telluronium group, and decreases with increasing chain length. Hence the degree of oligomerization can be selectively controlled by means of the ratio of the starting materials 1 and 2.

Cluster chemistry: XXXIII. Reactions of [{Au(PPh3)}3O]+ with [Ru3(μ3-C2But)(CO)9]−: X-ray structure of [Ru3Au2(μ3-CCHBut)(CO)9(PPh3)2], containing a t-butylvinylidene ligand attached to a trigonal-bipyramidal Ru3Au2 core

Abstract Deprotonation (K[HBBu 3 s ]) of HRu 3 (μ 3 -C 2 Bu t )(CO) 9 , followed by reaction of the anion with [O{Au(PPh 3 )} 3 ][BF 4 ], afforded the known complex Ru 3 Au(μ 3 -C 2 Bu t )(CO) 9 (9%), the vinylidene cluster Ru 3 Au 2 (μ 3 -CCHBu t )(CO) 9 (PPh 3 ) 2 (16%) and the hexanuclear Ru 3 Au 3 (C 2 Bu t )(CO) 8 (PPh 3 ) 3 (3%). The X-ray structure of the pentanuclear complex shows an asymmetric trigonal-bipyramidal Ru 3 Au 2 core (Ru, Au at the apices) with the Ru 3 face bridged by a t-butylvinylidene ligand, being σ-bonded to Ru(1) and Ru(3), and η 2 -coordinated to Ru(2). Crystals are monoclinic, space group P 2 1 / n with a 19.121(3), b 13.109(3), c 23.649(4) A, β 106.76(2)° and Z = 4. The structure was solved using 4405 observed diffractometer data, and refined to R 0.044, R w 0.047.

Insertion of an Oxygen Atom between Tellurium Atoms upon Oxidation of a Diaryl Telluride with NOBF4 or (CF3SO2)2O/O2: Dicationic Bis[diaryltellurium(IV)] Oxide

NO and O2 molecules are the source of the oxygen atom for dicationic µ-oxo(diaryltellurium) dimers 2 (X=BF4- , CF3 SO3- ), which form upon chemical oxidation of 1 with NOBF4 (method A) or (CF3 SO2 )2 O/O2 [method B, Eq. (a)]. The fate of the nitrogen atom of the oxidizing agent NOBF4 remains uncertain at this stage.