bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of Mononuclear Titanium Complexes Containing a Bis(phenoxy) Ligand Derived from 2,2′‐Methylene‐bis(6‐tert‐butyl‐4‐methylphenol)
Authors: Okuda Jun , Fokken Stefan , Kang Hak‐Chul , Massa Werner
Published: July 2007

A series of new titanium complexes of the general type Ti(mbmp)X2 (X = Br, I; OMe, OiPr, OtBu), containing a bidentate bis(phenoxy) ligand derived from 2,2′‐methylenebis(6‐tert‐butyl‐4‐methylphenol) (mbmpH2), was prepared. The 1H‐chemical shifts for the protons of the methylene link were found to vary considerably as a function of the ligand X. Reaction of Ti(OiPr)4 with two equivalents of mbmpH2 gave the C2‐symmetric spiro‐titanate complex Ti(mbmp)2. The crystalline labile solvent adducts of the dichloro complex Ti(mbmp)Cl2 with THF and DME were isolated and characterized. A single‐crystal X‐ray structural analysis revealed the THF adduct to be a mono(THF) adduct with a trigonal‐bipyramidal configuration, the bidentate mbmp ligand spanning an apical and equatorial site and the THF ligand occupying the remaining apical position.
Transition‐Metal Complexes with the Novel Poly (1,2,4‐triazolyl)borate Ligands [HnB(C2H2N3)4 − n]− (n = 1 and 2): Synthesis and Characterization of Metal Complexes of Dihydrobis(1,2,4‐triazolyl)borate as One‐ or Two‐Dimensional Coordination Polymers with Six‐Membered Ring Water Substructures and the Structure of Two‐Dimensional Liquid and Solid Water As Organized in the Intercalate [Ni{HB(C2H2N3)3}2] · 6 H2O (X‐ray Studies at 293 and 160 K)
Authors: Janiak Christoph , Scharmann Tobias G. , Hemling Holger , Lentz Dieter , Pickardt Joachim
Published: July 2007

The 1:2 manganese (5), nickel (6), and copper complex (7) with the novel dihydrobis(1,2,4‐triazolyl)borate ligand (2) were synthesized and structurally characterized. Single‐crystal X‐ray studies reveal the formation of highly solvated coordination polymers of the formula {[M(H2O)2{μ‐H2B(C2H2N3)2}2] · n H2O}∞ for M = Mn and Cu. In 5 (M = Mn; n = 4) a two‐dimensional metal‐ligand framework is built by means of the bridging action of 2. These metal‐ligand grid sheets sandwich water layers which comprise individual six‐membered rings. Compound 7 (M = Cu; n = 6) can be described as a linear metal‐ligand chain with two borate ligands bridging two copper centers. These one‐dimensional coordination polymers are separated by one‐dimensional arrays of water molecules in the form of edge‐sharing six‐membered rings. In both structures the water of crystallization is held in place both by hydrogen bonding from the aqua ligands and by hydrogen bonding to the nitrogen atoms of the borate ligand. Bis[hydrotris(1,2,4‐triazolyl)borato]nickel, [Ni{HB(C2H2N3)3}2] (8), was obtained from NiCl2 and the potassium salt of [HB(C2H2N3)3]− (1). Single‐crystal X‐ray structures of the solvate 8 · 6 H2O were determined at 293 and 160 K. The water molecules are arranged in two‐dimensional layers with only weak (hydrogen bonding) interactions to the adjacent layers of the complex molecules. The room temperature structure (orthorhombic, space group Cmca) shows a highly disordered water structure being indicative of a dynamic equilibrium between small conglomerates and free molecules. Upon cooling an ordering occurs in the water layer leading to a phase transition in the crystal, and in the low‐temperature structure at 160 K (orthorhombic, space group Pmnb) the hydrogen atoms and bonding network of the water structure could be determined. This structure is best described as being composed of individual rings or chain segments. The material surface morphology after loss of the water of crystallization was studied by scanning electron microscopy and the structural pattern correlated with the crystal packing.
Steric Control of Oxidative Trimerization of Alkynyl Ligands in Trimethylphosphane Palladium Complexes
Authors: Klein Hans‐Friedrich , Zettel Bernd D.
Published: July 2007

Alkynylpalladium compounds trans‐PdX(CCR)(PMe3)2 [R = CMe3, X = Cl (1), I (19); R = CMe2OH, X = Cl (2), Br (10), I (11); R = c‐Hex, X = Cl (3), Br (12), I (13); R = CHMe2, X = Br (4); R = CH2SiMe3, X = Cl (5), Br (14), I (15); R = COOEt, X = Br (6), I (7); R = Ph, X = Cl (8), I (17); R = n‐Pr, X = N3 (16), I (20); R = n‐Hex, X = I (21); R = SiPh3, X = Br (22)] and trans‐PdX(CCR)(PBu3)2 [R = SiMe3, X = Cl (9), I (18)] as well as trans‐PdX(CCR)(PPh3)2 [R = CMe3, X = Br (23); R = CH2SiMe3, X = Br (24), I (25)] are prepared by known methods. Thermal decomposition between 120 and 160°C results in a selective transformation only with trimethylphosphane complexes 1, 2, 10–, and 19. Oxidative trimerization of the alkynyl groups CCCMe2R′ and CC(c‐Hex) affording the enediynyl compounds trans‐PdX[C(CCCMe2R′) = C(CCCMe2R′)CMe2R′] (PMe3)2 [R′ = Me, X = Cl (26), I (27); R′ = OH, X = Cl (28), Br (29), I (30)] and trans‐PdX{C[CC(c‐Hex)]C[CC(c‐Hex)] (c‐Hex)}(PMe3)2 [X = Br (31), I (32)] appears to be controlled by balanced steric demands of phosphorus and alkynyl substituents. The steric control is investigated by melting) transformable monoalkynyl complex trans‐PdI(CCCMe2OH)(PMe3)2 (11) with non‐transformable[*] complex trans‐PdI[CC(n‐Pr)](PMe3)2 (20) to give a mixture (A) of transformed complexes with mixed substituents R. Similar results are obtained in other mixtures, when transformable PdBr(CCSiMe3)(PMe3)[1] is heated with the non‐transformable complexes PdBr[CC(n‐Pr)](PMe3)2[1] and 20 (mixture B) or transformable PdBr[CC(c‐Hex)](PMe3)2 (12) with non‐transformable PdBr[CC(n‐Pr)](PMe3)2[1] (mixture C).
Synthesis and Application of Ring‐Substituted Analogues of the [4‐(η‐Cyclopentadienylidene)‐4,7,7‐trimethyl‐4,5,6,7‐tetrahydro‐η5‐indenyl]‐ZrCl2 Ansa‐Metallocene System
Authors: Psiorz Christian , Erker Gerhard , Fröhlich Roland , Grehl Matthias
Published: July 2007

Reaction of the 2,5‐hexanedione‐derived bisfulvene 1 with RLi reagents (R = phenyl or n‐butyl) yields the ring‐closed [4‐(cyclopentadienylidene)‐7‐R‐4,7‐dimethyl‐4,5,6,7‐tetrahydroindenyl]dilithium reagents 3. Their reaction with MCl4 (M = Ti, Zr, Hf) gives the corresponding ansa‐group‐4‐metallocene dichloride complexes 4, 6, or 7. In a similar way the [7‐allyl‐4‐(η‐cyclopentadienylidene)‐4,7‐dimethyl‐4,5,6,7‐tetrahydro‐η5‐indenyl]metal dihalides (M = Ti, Zr) (6d, 4d) are prepared. Two diastereomers are formed in most cases, some of which could be separated. The five representative examples cis‐ and trans‐4c, trans‐4d, cis‐6c, and trans‐7c of these complexes were characterized by X‐ray diffraction. All these six‐membered ring‐annulated C1‐bridged ansa‐metallocene dichlorides exhibit extremely small D1ZrD2 angles (D1 and D2 denote the centroids of the cyclopentadienyl rings) of 116.5°, i.e., they are characterized by a very open bite of the bent metallocene wedge. The homogeneous Ziegler‐type catalysts derived from these ansa‐zirconocenes by activation with methylalumoxane have high activities and all produce low‐molecular mass atactic polypropylenes or propene oligomers.
Metallorganische Verbindungen der Lanthanoide, 89. Cyclooctatetraenyl‐Komplexe der frühen Übergangsmetalle und Lanthanoide, 6. (Cyclooctatetraenyl)[N,N′‐bis(trimethylsilyl)benzamidinato]‐und ‐[diphenylbis(trimethylsilylimido)phosphinato]‐Komplexe der Seltenen Erden; Röntgenstrukturanalyse von (C8H8)Tm[PhC(NSiMe3)2](THF), (C8H8)Lu[4‐MeOC6H4C(NSiMe3)2](THF) und (C8H8)Nd[Ph2P(NSiMe3)2](THF)
Authors: Schumann Herbert , Winterfeld Jörn , Hemling Holger , Hahn F. Ekkehardt , Reich Peter , Brzezinka Klaus‐Werner , Edelmann Frank T. , Kilimann Ulrike , Schäfer Martina , Herbst‐Irmer Regine
Published: July 2007

Organometallic Compounds of the Lanthanoids, 89. – Cyclooctatetraenyl Complexes of the Early Transition Metals and Lanthanoids, 6. – (Cyclooctatetraenyl)[N,N′‐bis(trimethylsilyl)benzamidinato]‐ and ‐[diphenylbis(trimethylsilylimido)‐phosphinato] Complexes of the Rare Earths; X‐Ray Structural Analyses of (C8H8)Tm[PhC(NSiMe3)2](THF), (C8H8)Lu[4‐MeOC6H4C(NSiMe3)2](THF), and (C8H8)Nd[Ph2P(NSiMe3)2](THF)

[(C8H8)Ln(μ‐Cl)(THF)2]2 or [(C8H8)Ln(μ‐O3SCF3)(THF)2]2 (Ln = Y, Ce, Pr, Nd, Sm, Tm, Lu) react with Na[4‐RC6H4C(NSiMe3)2] (R = H, OMe, CF3) or Li[PhC(NSiMe3)2] to give the monomeric (cyclooctatetraenyl)lanthanide benzamidinates (C8H8)Ln[4‐RC6H4C(NSiMe3)2](THF) [R = H, Ln = Y (1), Ce (4), Pr (6), Nd (8), Sm (10), Tm (12), Lu (15); R = OMe, Ln = Y (2), Ce (5), Pr (7), Nd (9), Sm (11), Tm (13), Lu (16); R = CF3, Ln = Y (3), Tm (14), Lu (17)]. The reaction of [(C8H8)Ln(μ‐Cl)(THF)2]2 (Ln = Ce, Pr, Nd, Sm) with Li[Ph2P(NSiMe3)2] in THF leads directly to the monomeric compounds (C8H8)Ln[Ph2P(NSiMe3)2](THF) [Ln = Ce (18), Pr (19), Nd (20), Sm (21)] in good yields. The 1H‐, 13C‐, 31P‐ and 29Si‐NMR and mass spectra of the new compounds as well as the molecular structures of 12, 16, and 20 are discussed. The Raman spectra of the complexes 1–3, 12, and 14–17 have been studied in detail.
Molecular Modeling, a Tool for Predicting Structural Effects on the Macrocyclization Reaction between Bis(vinyl or allyl) Dialdehydes and Thiophosphonic Bis(hydrazides)
Authors: Galliot Christophe , Caminade Anne‐Marie , Majoral Jean Pierre , Kuznikowski Maciej , Zablocka Maria , Pietrusiewicz K. Michal
Published: July 2007

The reaction of new phosphorus dialdehydes PhP(O)‐[(CH2)nCHCHC6H4CHO]2 (4a–c, 5a) (n = 0:4, n = 1:5; a:para, b:meta, c:ortho), with thiophosphonic bis(hydrazide) PhP(S)[NMeNH2]2 (6) yields macrocyclic compounds 9b′, c′, 10a′, 9a″, b″, c″, 10a″ and 9c′″, arising from the cyclocondensation of one, two, or three equivalents of each reagent, respectively. Molecular modeling of 4a‐c, 5a, 6 and of the intermediate monocondensation products 7a‐c, 8a was carried out and points out the importance of the geometry of the starting reagents in the competition between inter‐ and intramolecular cyclocodensation.
Syntheses and Structures of Intramolecularly Stabilized Organoaluminium Compounds
Authors: Müller Jens , Englert Ulli
Published: July 2007

The reaction of LiAr (Ar = 2‐[(dimethylamino)methyl]phenyl) with AlCl3, MeAlCl2, and Me2AlCl in a 1:1 ratio yields the corresponding organoaluminium compounds ArAlCl2, ArAl(Cl)Me, and ArAlMe2 (1–3). The alanes Ar2AlCl and Ar2AlMe (4 and 5) were synthesized from AlCl3 and MeAlCl2 with two equivalents of LiAr. The products ArAl(Cl)R [R = tBu, C(SiMe3)3] 6 and 7 are formed by the reaction of LiR with 1. The Lewis acid 1 adds the bases iPrNH2 and THF to yield the adducts 1 · iPrNH2 and 1 · THF. The structures of the products were deduced from the 1H‐, 13C‐, and 27Al‐NMR spectra and were confirmed by X‐ray structural determinations of 5 and 1 · iPrNH2.
Neuartige (η2‐Alkin)kupfer(I)‐carboxylat‐Komplexe
Authors: Lang Heinrich , Köhler Katrin , Zsolnai Laszlo
Published: July 2007

Novel (η2‐Alkyne)copper(I) Carboxylate Complexes

The reaction of Me3SiCCSiMe3 (1) with copper(I) carboxylates [Cu(μ‐O2CR)] (2a: R = Me; 2b: R = Ph) yields the tetranuclear compounds [(η2‐Me3SiCCSiMe3)[Cu(μ‐O2CR)]2)2 (3a: R = Me; 3b: R = Ph) and dimeric {(η2‐Me3SiCCSiMe3)[Cu(μ‐O2CR)]}2 (6a: R = Me; 6b: R = Ph). Compounds 6a and 6b could only be characterized by using IR and NMR techniques, since in solution these compounds eliminate 1 to afford 3a or 3b, respectively. Complexes 3a and 3b can additionally be synthesized by the reaction of [(η2‐Me3SiCCSiMe3)CuBr]2 (4) with [Ag(μ‐O2CR)] (5a: R = Me; 5b: R = Ph). In 6 two carboxylate moieties are μ‐bridging two (η2‐Me3SiCCSiMe3)Cu building blocks, and the Me3SiCCSiMe3 fragments are each η2‐coordinated to one copper atom. In 3 the Me3SiCCSiMe3 units are each η2‐coordinated to two copper atoms and are perpendicularly orientated to the copper(I) core; the four copper atoms form a square‐planar arrangement. Compounds 3a and 3b have been characterized by analytical and spectroscopic data (IR, 1H‐, 13C‐NMR, MS) and 3a by X‐ray analysis.
Monomere (Acetylacetonato)kupfer(I)‐Komplexe von Alkinen und 1,4‐Diinen
Authors: Lang Heinrich , Köhler Katrin , Büchner Michael
Published: July 2007

Monomeric (Acetylacetonato)copper(I) Complexes of Alkynes and 1,4‐Diynes

Monomeric (η2‐Me3SiCCSiMe3)Cu(acac) (3) is formed by the reaction of dimeric [(η2‐Me3SiCCSiMe3)CuBr]2 (1) with two equivalents of Na(acac) (2). In a similar manner Me2‐Si(CCSiMe3)2 (4) reacts with CuCl (5) and 2 to afford Me2Si[(η2‐CCSiMe3)Cu(acac)]2 (6). In compounds 3 and 6 an alkyne unit is η2‐coordinated to a monomeric Cu(acac) moiety with a copper atom in a planar environment. With the organometallic 1,4‐diyne (η5‐C5H4SiMe3)2Ti(CCSiMe3)2 (7), compound [(η5‐C5H4SiMe3)2Ti(CCSiMe3)2]Cu(acac) (8) is formed. In 8 both Me3SiCC ligands of the 3‐titanapenta‐1,4‐diyne fragment are η2‐coordinated to a monomeric Cu‐(acac) building block. The copper atom in 8 possesses a pseudo‐tetrahedral environment (shown by X‐ray analysis), built by the two Me3SiCC ligands of the (η5‐C5H4SiMe3)2‐Ti(CCSiMe3)2 moiety and the two oxygen atoms of the acetylacetonato ligand. 8 is additionally formed by the reaction of 3 or 6 with 7, or by treatment of [(η5‐C5H4SiMe3)2Ti(CC‐SiMe3)2]CuCl (9) with Na(acac) (2). The application of 3, 6, and 8 as precursors for the preparation of copper films in the CVD process of copper(I) is discussed.
Synthesis and Characterization of Copper, Nickel and Cobalt Complexes of N,N′‐Dimethyl‐2,11‐diaza[3,3](2,6)pyridinophane
Authors: Krüger Hans‐Jörg
Published: July 2007

The properties of the tetraazamacrocyclic compound N,N′‐dimethyl‐2,11‐diaza[3,3](2,6)pyridinophane (L‐N4Me2) as a ligand for some selected metal chlorides have been examined. The crystal structure of the uncoordinated ligand reveals a syn chair‐chair conformation. In solution, the ligand displays fluctional behavior. Reaction of L‐N4Me2 with the chlorides of copper(II), nickel(II), and cobalt(II) affords the complexes [Cu(L‐N4Me2)Cl2] · H2O (3), [Ni(L‐N4Me2)(H2O)Cl]Cl · H2O (4), and [Co(L‐N4Me2)Cl2] · 2 H2O (5) in which the ligand adopts a syn boat‐boat conformation. The crystal structures of 4 and 5 are presented. Due to the small cavity of the 12‐membered ring of the ligand, exclusively distorted cis‐octahedral coordination geometries are found at the metal sites. A comparison of structural data of several complexes with this ligand shows that the extent of the distortions from ideal octahedral geometry is mainly determined by the M‐Npy bond strength. The electronic as well as the solution properties of the described complexes have been investigated by electronic absorption spectroscopy. ESR spectroscopy, and electrochemical methods.
Zinc Complexes of Histidine‐Containing Di‐ and Tripeptides
Authors: Förster Martin , Vahrenkamp Heinrich
Published: July 2007

Nine dipeptides and one tripeptide containing histidine were converted into analytically pure zinc complexes. Four different compositions were observed. The peptides used as or converted into the monoacids LH (HisGly, GlyHis, HisPhe, HisHis) form the compounds ZnL2 (11a, 12–14) and alternatively (HisGly, HisGlyGly) the compounds ZnL(BF4) (11b, 20). The peptides used as amides (HisGlyNH2, HisMetNH2) act as neutral ligands in the compounds ZnL2(ClO4)2 (15, 16). The three remaining peptides (HisAsp, AlaHis, β‐AlaHis) behave like diprotonic acids LH2 forming the compounds ZnL (17–19). Spectra and solubilities indicate that complexes 11a, 13, 15, and 16 are mononuclear containing two chelating peptides bound by their amino and imidazole nitrogen atoms. All other complexes seem to be coordination polymers in some of which the amide N and O atoms are involved in the coordination. This was proven by a structure determination for Zn(GlyHis)2 (12) in which the zinc ions are coordinated octahedrally by two histidine N, two amino N, and two amide O atoms of four peptide residues.
Synthesis, Structure, and Electrical Properties of Ta4FeTe4
Authors: Neuhausen Jörg , Finckh Ernst Wolfgang , Tremel Wolfgang
Published: July 2007

Ta4FeTe4 has been synthesized and its structure determined by single‐crystal X‐ray methods. It crystallizes in the ortho‐rhombic space group Pbam with Z = 4 and a = 10.514(5), b = 18.275(7), and c = 4.815(1) Å. Ta4FeTe4 has a chain structure built up by Fe‐centered Ta8‐square antiprisms sharing common square faces. The resistivity of Ta4FeTe4 has been measured by a two‐point method. Ta4FeTe4 shows metallic behavior. The structure of Ta4FeTe4 is discussed in relation to other early transition metal cluster compounds. A rational approach to the synthesis of related compounds is proposed.
1,4,2‐Diazaphospholothiazoles and ‐pyridines by a Hantzsch‐Type Condensation Using Chloromethyldichlorophosphane
Authors: Karaghiosoff Konstantin , Cleve Cornelia , Schmidpeter Alfred , Mahnot Ruchi , Gandhi Neelam , Bansal Raj K.
Published: July 2007

The [3 + 2] cyclocondensation of 2‐amino‐1,3‐thiazoline, 2‐aminopyridines, 2‐ and 4‐aminopyrimidines, 2‐aminopyrazine, and 2‐aminoquinoline with chloromethyldichlorophosphane in the presence of triethylamine yields regiospecifically 5,6‐dihydrothiazolo[2,3‐e][1,4,2]diazaphosphole (3), 1,4,2‐diazaphospholo[4,5‐α]pyridines (12), 1,4,2‐diazaphospholo[4,5‐α]pyrimidines (15), 1,4,2‐diazaphospholo[4,5‐e]pyrimidine (17), 1,4,2‐diazaphospholo[4,5‐α]pyrazine (19), and [1,4,2]diazaphospholo[4,5‐α]quinoline (22), respectively. Using 2‐amino‐1,3‐thiazole (4) and 2‐aminobenzothiazoles 8, we obtained mixtures of the 1,5‐ and 4,5‐anellated 1,4,2‐diazaphospholes 5/6, 9a/10a and 9b/10b, while in the case of the methyl derivative 8c only the [1,4,2]diazaphospholo[5,4‐b][1,3]benzothiazole 10c was formed. In the reaction of 2‐aminothiazole and 2‐aminopyrazine with Chloromethyldichlorophosphane the bis(diazaphospholo)‐substituted chloromethylphosphanes 7 and 20 could be detected. The new anellated 1,4,2‐diazaphospholes are colorless to pale yellow crystalline moisture‐sensitive solids.
Reactions of Complex Ligands, LXIV. Synthesis of 5,5′‐Diphenyl‐2,2′‐bifuran, a Biaryl Compound with Remarkable Fluorescence Properties
Authors: Christoffers Jens , Dötz Karl Heinz
Published: July 2007

The 2‐oxacyclic α,β‐unsaturated carbene complex 1 reacts with an excess of dimethylamine to give the diphenylbifuran 2. The structure of 2 was established by independent synthesis from 2‐phenylfuran (4) via regioselective lithiation and transmetalation to zinc and tin organometallics 6a‐c and final oxidative copper coupling reactions.
Chirotopic and Stereogenic Metal Centers in [M(L)(L')(‘RS4’)] Complexes with Chiral Thioether‐Thiolate Ligands ‘RS4’‐H2 [‘MeS4’2− = 1,2‐bis(2‐mercaptophenylthio)propanato(2‐), ‘CH3(CH2)2S4’2− = 1,2‐bis(2‐mercaptophenylthio)pentanato(2‐), ‘HO(CH2)9S4’2−10
Authors: Sellmann Dieter , Bail Petra , Knoch Falk , Moll Matthias
Published: July 2007

In order to investigate the stereochemistry of substitution reactions of chiral pseudo‐octahedral complexes the chiral thioether‐thiolate ligands ‘RS4’‐H2 (= HSC6H4SCHRCH2‐SC6H4SH) with R = CH3‐ (5), CH3(CH2)2‐ (6), HO(CH2)9‐ (7), and PhCH2‐ (8) were synthesized by template alkylation of Na2[Ni(‘S2’)2] [‘S2’2− = 1,2‐benzenedithiolate(2‐)] with 1,2‐dibromoalkanes BrCHRCH2Br (R = CH3‐, 1; R = CH3(CH2)2‐, 2; R = HO(CH2)9‐, 3; R = PhCH2‐, 4) and isolated after hydrolyses. Reactions of ‘RS4’‐H2 with [RuCl2(PPh3)3] or [Mo(O)2(acac)2] yielded [Ru(PPh3)2(‘RS4’)] (R = CH3‐, 9; R = HO(CH2)9‐, 10; R = PhCH2‐, 11) and [Mo(O)2(‘MeS4’)] (12). [Ru(PPh3)2(‘MeS4’)] · 2 CH2Cl2 (9 · 2 CH2Cl2) and [Mo(O)2(‘MeS4’)] (12) were characterized by X‐ray structure determination. In both complexes, the metal centers are surrounded pseudo‐octahedrally by four sulfur donors of the ‘MeS4’ ligand and two cis coligands. The methyl substituent at the stereogenic C* atom of the C2 bridge of the ‘MeS4’ ligands assumes an equatorial position. In addition, the metal centers of these complexes are chirotopic and prostereogenic. Crystal data of 9 · 2 CH2Cl2 in comparison with [Ru(PBu3)2(‘S4’) 11‐bis(2‐mercaptophenylthio)‐1‐undecanolato(2‐), ‘PhCH2S4’2−1,2‐bis(2‐mercaptophenylthio)‐3‐phenylpropanato(2‐)] ] and those of 12 in comparison with [Mo(O)2(‘S4’)] show that distances and angles of the coordination cores are not influenced by the substituents on the C2 bridge. Reactions of the [Ru(PPh3)2(‘RS4’)] complexes (9–11) with the achiral substrates CO and PMe3, however, yielded diastereomers of [Ru(PPh3)(L)(‘RS4’)] (L = CO, R = CH3‐, 13; L = CO, R = HO(CH2)9‐, 14; L = CO, R = PhCH2‐, 15; L = PMe3, R = CH3‐, 16; L = PM R = HO(CH2)9‐, 17; L = PMe3, R = PhCH2‐, 18) in diastereomeric excesses between 60 and 82%. The diastereomer of [Ru(PPh3)CO)(‘MeS4’)] (13) which could be characterized by X‐ray structure determination exhibits the CO ligand in trans position to the thioether donor which is bound to the stereogenic C* atom of the C2 bridge. Reaction of 9 · 2 CH2Cl2 with the optically pure bidentate diphosphine (+)‐(S,S)‐DIOP [= (+)‐2,3‐O‐isopropylidene‐2,3‐dihydroxy‐1,4‐bis(diphenylphosphino)butane] yielded 1:1 mixtures of two diastereomers of [Ru(DIOP)(‘MeS4’)] (19) one of which was separated in pure form by HPLC.
Chiral Organometallic Reagents, XIV. Theoretical Investigations into the Mechanism of Inversion of Configuration at the Carbon Center of α‐Sulfur‐Substituted Carbanions
Authors: Dress Ruprecht K. , Rölle Thomas , Hoffmann Reinhard W.
Published: July 2007

Ab initio calculations showed that the two elementary steps in the racemization of the α‐methylthioethyl anion (7), inversion of the pyramidal anionic center, and rotation around the C−S bond, occur in sequence and are not concerted. The former process passes over a barrier of 1.1 kcal/mol, the latter over one of 10.9 kcal/mol. MNDO calculations on the α‐phenylthioethyl anion (8) revealed a preferred conformation of the S‐aryl bond, allowing maximum delocalization of the sulfur lone pairs into the π* orbital of the aryl group. This orientation is maintained during rotation around the C−S bond and is the origin of steric hindrance in the racemization of certain α‐arylthio‐, α‐arylseleno‐, and α‐aryltelluroalkyllithium compounds 1 to 6.
A T‐Shaped Selenenyl Halide: Synthesis and Characterisation of a Proposed Reaction Intermediate
Authors: Jones Peter G. , Ramírez Arellano M. C. De
Published: July 2007

The T‐shaped selenenyl halide (1), which may be regarded as a model substance for the transition state in nucleophilic displacement at divalent chalcogen atoms, has been isolated and subjected to X‐ray structure determination.
N,N′ ‐Disilylated 1,4‐Dihydropyrazines: Organosilyl Substitution Reactions, Structural Effects of Steric Hindrance, and Electron Exchange with C60
Authors: Lichtblau Alexander , Ehlend Anja , Hausen H.‐D. , Kaim Wolfgang
Published: July 2007

Organosilyl exchange reactions of the extremely electronrich and formally “antiaromatic” 1,4‐bis(trimethylsilyl)‐substituted 1,4‐dihydropyrazine 1 with Ph3SiCl or Me5Si2Cl yielded the new compounds 2 and 3 with triarylsilyl and disilanyl substituents. At δ = 4.53 in CDCl3 compound 3 shows a particularly high‐field shifted 1H‐NMR resonance for the 1,4‐dihydropyrazine protons. In contrast to the planar ring arrangement of 1,4‐bis(triisopropylsilyl)‐1,4‐dihydropyrazine 4, the crystal structure determination of the 2,5‐dimethylated analogue 5 as obtained by reductive silylation exhibits a pronounced boat conformation of the heterocycle due to steric repulsion between the substituents, the closest H…H (CH3/ CH) contact being 211 pm. Despite the sizeable structural differences between 4 and 5 both compounds are reversibly oxidized at very negative potentials, at ‐0.90 and ‐0.85 V vs. Fc+/0, respectively, It appears that the electrochemical behavior of this class of compounds is determined ***primarly by the configuration at the nitrogen centers and less by the ring conformation. Compound 4 reacts with C60 under EPR‐detectable electron exchange to afford 4+* and C. The radical cation 4+* generated separately via oxidation with iodine was characterized by low‐temperature UV/Vis and ENDOR spectroscopy. An ENDOR spectrum revealing silylalkyl coupling was also obtained for the related radical cation of reversibly oxidizable 1,1′ ‐bis(tert‐butyldimethylsilyl)‐1,1′,4,4′ ‐bipyridylidene (8).
Zinc Complexes of S,N Ligands Derived from Thiazolines
Authors: Brand Udo , Vahrenkamp Heinrich
Published: July 2007

Three different thiazoline derivatives or their tautomeric mercaptoethylamine derivatives were used for the preparation of zinc complexes containing S,N ligands. 2‐(2‐pyridyl)‐3‐(2‐pyridylmethyl)‐1,3‐thiazolidine (PPMT) could not be opened reductively but acted as a tridentate nitrogen ligand in (PPMT)ZnX2 (1a, b, X = Br, NO3). The thiazolidine tautomer N‐(2‐mercaptoethyl)salicylideneimine (MESIH2) yielded polymeric (MESI)Zn (2) and, after oxidation, monomeric (MESI)2Zn (3) containing a disulfide unit. The 2‐aryl‐benzo‐1,3‐thiazoline tautomers N‐(2‐mercaptophenyl)‐p‐fluoroben‐zylideneimine (MPFBH) and N‐(2‐mercaptophenyl)‐p‐meth‐oxybenzylideneimine (MPMBH) underwent reaction with diethyl zinc resulting in the unstable L . Zn‐Et complexes 4a and b, which are probably dimeric and the stable 2:1 complex (MPFB)2Zn (5). The structures of 3 and 5 were determined and were found to exhibit distorted tetrahedral ZnN2O2 and ZnN2S2 coordinations, respectively.
Transition‐Metal‐Substituted Gallanes: Synthesis and Spectroscopic Studies of Highly Polar σ(M—Ga) Bonds, Structures of trans‐(Ph3P)(CO)3Co—Ga[(CH2)3N(C 2H5)2]R (R = Cl, CH3) and (n5‐C5H5)(CO)2Fe—GaCl2 [N(CH3)3]
Authors: Fischer Roland A. , Miehr Alexander , Priermeier Thomas
Published: July 2007

The salt elimination reaction of the transition carbonyl metal‐lates [L(CO)nM](Na/K) (M = Cr, Mo, W, Mn, Re, Fe, Co, Ni; L= CO, n5‐C5R5, PR3; n= 1‐4; R= alkyl, aryl) with the base‐stabilized galliumhalides ClaGaR3 ‐a(Do) (R = H, alkyl, halide; Do = THF, N(CH3)3, NC7H13) or ClaGa[(CH2)3N‐R2](R)2 ‐ a yielded almost quantitatively the transition metal‐substituted, gallanes [L(CO)nM]aGaR3 ‐ a(Do) and [L(CO)n‐M]aGa[(CH2)3NR2](R)2 ‐ a, respectively. Residual halide functionalities in these complexes were selectively replaced by various other groups. The new compounds were characterized by means of elemental analysis, 1H‐, 13C‐, 31P‐NMR, MS, and lR v(CO) data. The single‐crystal X‐ray structure analysis of trans‐(Ph3P)(CO)3Co‐Ga[(CH2) 3N(C2H5)2](R)( 6s: R = Cl, 6t: R= CH3) showed s̀(Co‐Ga) lengths of 237.78(4) and 249.5(1) pm, respectively. A short s̀(Fe‐Ga) contact of 236.18(3) pm was found for (n5‐C5H5)(CO)2Fe‐Ga‐Cl2[N(CH 3)3] (5a). Low‐pressure MOCVD experiments were performed to give thin films of analytically pure CoGa alloy.
Synthesis of 7‐Alkyl/aryl‐1,3,5‐triaza‐7‐phosphonia‐adamantane Cations and Their Reductive Cleavage to Novel N‐Methyl‐P‐alkyl/aryl[3.3.1]bicyclononane Ligands
Authors: Assmann Bernd , Angermaier Klaus , Paul Martin , Riede Jürgen , Schmidbaur Hubert
Published: July 2007

Two reaction pathways for the synthesis of 1,3,5‐triaza‐7‐phosphoniaadamantane salts, RP[(CH2)6N3]+X‐ (1), were followed. Route 1 starts with commercial tetrakis(hydroxymethyl)phosphonium chloride, which is converted into P(CH2OH)3 by treatment with a base. Subsequent quaternization with alkyl halides RX and cyclization with formaldehyde and ammonia afford [R‐TPA]+X‐. This process is only applicable for R = Me (1a) and Et (1b), however. Route 2 is more general and starts with primary phosphanes RPH2, which are converted into organotris(hydroxymethyl)phosphonium salts with formaldehyde and hydrochloric acid followed by ring closure with CH2O/NH3 to give compounds 1c–1f (R = t‐Bu, c‐Hex, Bz, and Ph, respectively, and X = Cl, I, PF6, or BPh4). Reductive cleavage of compounds 1 by sodium in liquid ammonia proceeds with either external (P‐R) or internal (P‐CH2) bond rupture. P‐R cleavage affords the 1,3,5–triaza‐7‐phosphaadamantane (TPA), while cage cleavage leads to new bowl‐ or helmet‐shaped ligand systems with peripheral amine and phosphane functions (2). Yields of the cage‐opening reaction are highest for R = Ph (2f), moderate for R = Me and Et (2a, 2b), and poor with the remaining R groups (2c–2e). A radical mechanism is proposed for this reaction, the leaving group properties of R determining the direction of the cleavage. The crystal and molecular structures of compounds 2a and 2f were determined by X‐ray diffraction studies. Exo positions were found for the N‐Me and P‐R groups. The isomers with the R group in the endo position are also present in solution in small amounts, as detected by NMR spectroscopy. Isomer interconversion by P inversion is slow on the NMR time scale. Compounds 2a, 2b and 2f were oxidized with elemental sulfur and selenium to give the monosulfides and selenides, respectively (2aS, 2aSe, 2bS, 2bSe, 2fS, 2fSe). Oxidation with H2O2 led to degradation. Compound 2a was quaternized at the P atom by treatment with Mel to give the corresponding phosphonium salt. Treatment with equimolar quantities of (Me2S)AuCl led to the 1:1 complexes 2aAucl, 2bAuCl and 2fAuCl, with the AuCl units solely P‐bonded, as determined by X‐ray diffraction of 2aAuCl and 2fAuCl. Compound 2a forms an ionic 2:1 complex with AuCl, composed of the ions [(2a)2Au]+ Cl‐ (with unidentate ligands), while its reaction with [Me2AuCl]2 leads to [Me2Au(2a)]+ [Me2AuCl2]‐ (with a chelating 2a ligand), as again confirmed by crystal structure analysis in both cases. Ligands 2a, 2b and 2f also act as chelating ligands in their tetracarbonylmolybdenum complexes obtained in the reactions with (C7H8)Mo(CO)4.
Catalytic, Diastereoselective Aldol Reactions Using Titanium(IV) Halides
Authors: Mahrwald Rainer
Published: July 2007

The aldol reaction in the presence of titanium halides is described. Good yields of aldols 10–17 were obtained even with only catalytic amounts of titanium tetrafluoride. The reactions were carried out in the absence of a base.
1,1‐Hydroborierung von Alkinen mit 6‐Aza‐nido‐decaboranen
Authors: Meyer Franc , Schmidt Martin U. , Paetzold Peter
Published: July 2007

1,1‐Hydroboration of Alkynes with 6‐Aza‐nido‐decaboranes[1]

Alkynes ACCR′ (R′ = Me, Bu, tBu, SiMe3), that contain a mobile group A, like H or SiMe3, undergo hydroboration by 6‐aza‐nido‐decaboranes RNB9H11 (1a‐c, R = H, Ph, PhCH2) and 1,2‐migration of the group A, to give the corresponding 9‐(1‐alkenyl)‐6‐aza‐nido‐decaboranes RNB9H10(CH=CR′A) (2a‐h). Ethenes AHC=CH2 (A = SiMe3, SnBu3) are hydroborated by 1a, b as well to form products of the type RNB9H10(CH2CH2A) (3a‐c). The alkyne Me3SiCCH undergoes a hydroboration with 1b twice; the formation of (PhNB9H10)2CHCH2SiMe3 (4) proceeds by a 1,1‐ and a 1,2‐hydroboration step, apparently. The crystal structure analysis of (PhCH2)NB9H10[CH=CMe(SiMe3)] (2e; space group Pl) reveals a (Z configuration of the ethene moiety.
Laboratory Scale Direct Synthesis of Pure AuF3
Authors: Tornieporth‐Oetting Inis C. , Klapötke Thomas M.
Published: July 2007

Pure AuF3 has been prepared in high yield from the elements in a convenient and safe one‐pot laboratory scale reaction. The identity and purity was clearly established by vibrational spectroscopy, mass spectrometry and microanalytical data.
Synthesis and Reactivity of Silicon‐Transition Metal Complexes, 3l. Metallosilanols and Metallosiloxanes, 6. Die ersten Hydroxysilandiyl‐verbrückten Zweikernkomplexe: Selektive Oxygenierung der Silicium‐Brücke in Silandiyleisen‐Komplexen mit Dimethyldioxiran
Authors: Malisch Wolfgang , Hindahl Kathrin , Käb Harald , Reising Joachim , Adam Waldemar , Prechtl Frank
Published: July 2007

Synthesis and Reactivity of Silicon‐Transition Metal Complexes, 31 — Metallosilanols and Metallosiloxanes, 6. — The First Hydroxysilanediyl‐Bridged Binuclear Complexes: Selective Oxofunctionalization of the Silicon Bridge in Silanediyliron Complexes with Dimethyldioxirane

Oxygenation of [μ‐(R)(H)Si][Fe(CO)2Cp]2 [R = Me (1a), pTol (1b)] with dimethyldioxirane (2) yields the μ‐(hydroxysilanediyl)bisiron complexes [μ‐(R)(HO)Si][Fe(CO)2Cp]2 [R = Me (3a), pTol (3b)]. In an analogous manner the cyclic complex (μ‐OC)[μ‐(Mes)(H)Si][Fe(CO)Cp]2(Fe‐Fe) (6) obtained by photochemical reaction of Cp(OC)2Fe‐Me (4) with MesSiH3, (5) is converted into (μ‐OC)[μ‐(Mes)(HO)Si][Fe(CO)Cp]2‐(Fe‐Fe) (7). 6 and 7 are obtained as a mixture of cis(Mes), cis(H or OH), and trans isomers.
Tri‐tert‐butylazadiboriridin: Ringerweiterung mit Isonitrilen, α‐Bromlithioalkanen und Aziden
Authors: Luckert Stefan , Eversheim Ellen , Müller Matthias , Redenz‐Stormanns Burkhard , Englert Ulli , Paetzold Peter
Published: July 2007

Tri‐tert‐butylazadiboriridine: Ring Prolongation by the Action of Isonitriles, α‐Bromolithioalkanes, and Azides

Isonitriles ArNC are 1,1‐boroborated by the B‐B bond of the azadiboriridine (‐BR‐BR‐NR‐) (1; R = tBu) to form the four‐membered ring [‐BR‐C(NAr)‐BR‐NR‐] (2b; Ar = 2,6‐C6H3Me2). Corresponding rings undergo [3 + 3] cyclodimerization of the B‐C=N chain to give the tricyclic products 6a, b when isonitriles RNC with the small ligands R = Me, Et are boroborated by 1. Two molecules of tBuNC open the B‐B bond of 1; the resulting five‐membered ring 7a may add excess tBuNC to yield 7a · 2 CNtBu (8). The results strongly support a mechanistic hypothesis set up for the multistep reaction of 1 and CO. The carbene units, which are present in the α‐bromolithioalkanes [‐C(Br)Li‐CMe2‐CH2‐], LiC(Br)H2, and LiC(Br)Me2, are also 1,1‐boroborated by 1 to give the corresponding four‐membered ring 2c, or by a 2:1 reaction to afford the five‐membered ring 7b, or by a 1:1 reaction and subsequent rearrangement to yield the five‐membered ring 7c. The nitrene units, which are present in the azides PhN3 and PhCH2N3, are also boroborated by 1; the diazadiboretidines 5b, c are formed with evolution of N2. The bis(diazadiboretidinyl)borane RB(N2B2R3)2 (5d) is the corresponding product from the reaction of RB(N3)2 with 1 in the ratio 1:2. The azide Me3SiN3 reacts differently yielding the N‐boryl diazadiboretidine 5e and the iminoborane RB≡N̊. The B‐B bond length of 187.6 pm in 5e indicates a transannular bonding interaction. The products 5d, 5e, and 6a were characterized by a crystal structure analysis.
Highly Substituted Tris(pyrazolyl)methane Ligands and Some Zinc Complexes Thereof
Authors: Titze Christoph , Hermann Jörg , Vahrenkamp Heinrich
Published: July 2007

Tris(pyrazolyl)methane ligands in which two or three of the pyrazole carbon atoms bear organic substituents (L1‐L7) were synthesized from chloroform and the corresponding pyrazole under phase transfer conditions. Their behavior towards zinc salts was found to span the range from no reaction at all to hydrolytic destruction. One hydrolysis product isolated and structurally characterized was the perchlorate complex [(HPz5)3Zn‐OClO3]ClO4 (1), other ones were the 2:1 complexes (HPz3)2ZnBr2 (2) and (HPz6)2Zn(NO3)2 (3, HPzn = substituted pyrazole). Zinc perchlorate and tris(trimethylpy‐razolyl)methane (L2) formed the octahedral binary complex [L22Zn](ClO4)2 (4) as evidenced by a structure determination. Zinc halides produced the 1:1 complexes L1 · ZnBr2 (5), L4 · ZnCl2 (6), and L4 · ZnBr2 (7), which according to the structure determinations of 6 and 7 contain tetrahedral ZnN2Hal2 units with only bidentate tris(pyrazolyl)methane ligands. In contrast, the zinc nitrate complex L4 · Zn(NO3)2 (8) was found to have an octahedral structure with mono‐ and bidentate nitrate and tridentate L4. The bromide complex 7 was converted by silver perchlorate hydrate into the labile compound [L4 · ZnBr]ClO4 (9) and then into the unstable product [L4 · Zn‐OH2](ClO4)2 (10), both presumed to contain zinc in a tetrahedral ZnN3Br or ZnN3O environment, respectively. The ease of hydrolytic self‐destruction prevented the exploitation of the reactivity of 9 and 10 in analogy to that of the corresponding tris(pyrazolyl)borate zinc complexes.
Metal Complexes with Tetrapyrrole Ligands, LXIX. Facile Synthesis and 13C‐NMR Spectrum of Dichloro(octaethylporphyrinato)zirconium(IV)
Authors: Buchler Johann W. , Eberle Mike
Published: July 2007

The synthesis of dichloro(2,3,7,8,12,13,17,18‐octaethylpor‐phyrinato)zirconium(IV), Zr(oep)Cl2, from zirconium tetrachloride and octaethylporphyrin, H2(oep), is described. The reported synthesis is a new and simple route to this precursor of organometallic compounds. Zr(oep)Cl2 was characterized by elemental analyses, 1H‐ and 13C‐NMR, UV/Vis, and mass spectra. Hydrolysis yielded a mixture of mono‐ and binuclear hydroxy zirconium(IV) porphyrins.
Octacarbonylbis {μ‐(tris(trimethylsilyl)methyl]indany l} dimanganese with Two Monoalkyl Indium Groups Bridging the Mn–Mn Bond
Authors: Uhl Werner , Keimliling Sven Uwe , Hiller Wolfgang , Neumayer Markus
Published: July 2007

Tetrahedra‐tetrakis[tris(trimethylsilyl)methyl]tetraindane(4) (1) reacts with decacarbonyldimanganese(0) to yield the bright red crystalline title compound 2, in which two carbonyl ligands are replaced by two InR fragments. The crystal structure determination of 2 shows two Mn(CO)4 groups (Mn‐Mn 313.7 pm) bridged by two monoalkylindium units and a planar Mn2In2 molecular center.
Tethered 2,2′‐Bipyridine Ligands — Synthesis and Coordination Properties
Authors: König Burkhard
Published: July 2007

Bis‐2,2′‐bipyridine ligands tethered by phthalic‐ and tere‐phthalic esters were synthesized. The coordination with copper(I) and silver(I) ions gave mononuclear complexes. With terepthalic acid as a spacer between 2,2′‐bipyridines 2 + 2 assemblies were identified in traces. The coordination compounds were investigated by electrospray mass spectroscopy.
[Cp4Fe4(E2)2] Clusters with Triangulated Dodecahedral Fe4E4 Skeletons (E = P, As)
Authors: Scherer Otto J. , Kemény Gunther , Wolmershäuser Gotthelf
Published: July 2007

The thermolysis of [CpFe(CO)2]2 (1) and P4 or As4 affords the iron clusters [Cp4Fe4(E2)2], E = As (2a), P (2b), the Fe4E4 skeleton of which consists of a triangulated dodecahedron. S8 and gray Se oxidize the P2 ligands of 2b with formation of [Cp4Fe4(P2X2)2], X = S (3a), Se (3b), complexes with the hitherto unknown P2X2 ligands, 2a, b and 3a, b have been characterized by X‐ray crystallography.
Öffnung des Aza‐closo‐dodecaboran‐Gerüsts durch Basen
Authors: Lomme Petra , Meyer Franc , Englert Ulli , Paetzold Peter
Published: July 2007

Opening of the Aza‐clso‐dodecaborane Skeleton by Bases

The aza‐closo‐borane PhNB11H11 (1a) is opened by the amines NR3 (R = Me, Et) to give the novel aza‐nido‐dodecaboranes PhNB11H11(NR3) (2a, b). The non‐planar open pentagonal face of 2a, b accomodates the N atom, a BHB bridge, and the base‐bound B atom, according to NMR spectra and the crystal structure analysis of monoclinic 2b. A similar but more symmetric structure is found when closo‐RNB11H11 (1a‐c, R = Ph, Me, H) is attacked by anionic bases X− to give nido‐RNB11H11X− (3a‐j; R/X = Me/H, Me/F, Me/Cl, Ph/OH, H/OMe, Me/OMe, Me/OtBu, Me/NEt2, Me/Me, Me/Bu). The anions are precipitated with cations [K([18]crown‐6)], [S(NMe2)3], [N(PPh3)2], [Et2NH2], or [Li(tmeda)2]. The nido‐structures of type 2 and 3 are derived from the hypothetical closo‐NB12H13.
The Chemistry of 1,3,5‐Triazacyclohexane Complexes, 3. High Yield Synthesis of [Cr{N(SiMe3)2}3] and Accurate Structure Determination by Cocrystallization with Me6Si2
Authors: Köhn Randolf D. , Kociok‐Köhn Gabriele , Haufe Matthias
Published: July 2007

The reaction of N,N′,N′′‐trimethyl‐1,3,5‐triazacyclohexane chromium trichloride ((Me3TAC)CrCl3, 1) with LiN(SiMe3)2 or NaN(SiMe3)2 in petroleum ether yields nearly quantitatively [Cr{N(SiMe3)2}3] (2) with loss of the Me3TAC ligand. Compound 2 could be crystallized from hexamethyldisilane as [Cr{N(SiMe3)2}3] · (Me6Si2)0,5 which allowed the refinement of the X‐ray crystal structure in the trigonal space group P‐31c (no. 163) (a = 16.012(3) Å, c = 8.4796(12) Å, V = 1882.8(6) Å3, Z = 2) without severe disorder.
The First Selective Cage Redistribution Reaction of P4O6
Authors: Strojek Stephan , Jansen Martin
Published: July 2007

Reaction of tetraphosphorus hexaoxide with organic azides leads selectively to the cage redistribution products1P4O6NPh,2P4O6NC2H4Ph,3P4O6NSO2CH3,4P4O6NC6H13, and5P4O6NCO2C2H5by nitrene insertion. The molecular structure consists of an adamantane‐like P4O5N cage with a terminally bound oxygen atom. The P4O5N cagelike structure is confirmed by31P NMR spectroscopy and X‐ray structure analysis. The P4O5N cages of the P4O6NR molecules possess a significant geometrical distortion.
Metal Complexes with Tetrapyrrole Ligands, LXX. Synthesis, Characterization, and Variable‐Temperature 1H‐NMR Investigations of Cerium(IV) and Zirconium(IV) Double‐Deckers Derived from 2,3,7,8,12,13,17,18‐Octaethyl‐5‐methylporphyrin
Authors: Buchler Johann W. , Heinz Georg
Published: July 2007

The synthesis of bis(2,3,7,8,12,13,17,18‐octaethyl‐5‐methyl‐porphyrinato)cerium(IV) and ‐zirconium(IV) [M(oemep)2; M = Ce, Zr, respectively] is described. The complexes were characterized by UV/Vis and IR spectroscopy and cyclic volt‐ammetry. 1H‐NMR spectra of the new cerium and zirconium sandwich complexes show that they exist as a mixture of vicinal and transversal isomers due to the rigid square‐antipri‐smatic coordination geometry found in metal(IV) bis(porphy‐rinates). From the temperature dependence of the 1H‐NMR spectra the rotational rigidity of the double‐decker system was deduced. In toluene, free rotation of the two porphyrin macrocycles with respect to each other does not occur up to 373 K.
Hybrid Diborolyl/Dicarbaboranyl Triple‐Deckers: [(μ5‐Cyclopentadienyl)cobalt][μ,η5‐1,3‐diborolyl)cobalt[dicarba‐heptacarboranyl and ‐nonacarboranyl Complexes
Authors: Weinmann Wolfgang , Metzner Frank , Pritzkow Hans , Siebert Walter , Sneddon Larry
Published: July 2007

The three‐component reactions of the sandwich anion [(η5‐C5H5)Co(η5‐Et4MeC3B2)]− (4‐H)− and various dicarbaborane anions with metal halides are described. Thus, (4‐H)−, nido‐4,5‐C2B6H9− (5), and CoCl2 form the 30VE triple‐decker [η5‐C5H5)Co(μ,η5‐Et4MeC3B2)Co(η5‐2,3‐C2B5H7)] (6). An analogous three‐component reaction of (4‐H)−, arachno‐4,5‐C2B7H−2 (7), and CoCl2 yields [(η5‐C5H5)Co(μ,η5‐Et4‐MeC3B2)Co(η5‐6,9‐C2B7H9)] (8), which rearranges on heating (57°C) to give the 1,6‐isomer [(η5‐C5H5)Co(μ,η5‐Et4‐MeC3B2)Co(η5‐1,6‐C2B7H9)] (9) with an activation energy of 127 · 10 kJ/mol. The thermodynamically most stable 1,10‐isomer [(η5‐C5H5)Co(μ,η5‐Et4MeC3B2)Co(η5‐1,10‐C2B7H9)] (10) is formed by heating of 9 at 180°C. An alternative route to 9 is provided by the reaction of arachno‐6,8‐C2B7H12− (11) with (4‐H)− and CoCl2. The analogous reaction with RhCl3 leads to [(η5‐C5H5)Co(μ,η5‐Et4MeC3B2)Rh(1,6‐C2B7H9)] (15) and unexpectedly to closo‐2‐(η5‐C5H5)Co(1,6‐C2B7H9) (12). The constitutions of the described compounds are derived from their 1H‐, 11B‐, 13C‐NMR data as well as mass spectral data. The X‐ray structure analyses of 10 and 12 show the expected metal complexes with a CoC2B7H9 framework. In 10 the carbon atoms occupy the capping positions of a bicapped square antiprism. The short Co‐Co distance of 3.20 Å is in agreement with the 30VE configuration of 10. In both 10 and 12, the distance from the cobalt to the four‐coordinate C4 is the shortest Co‐to‐cage atom distance.
Tripod‐Cobalt‐Formiat‐Komplexe in den Oxidationsstufen +II und +I
Authors: Sernau Volker , Huttner Gottfried , Scherer Johannes , Walter Olaf
Published: July 2007

Tripod‐Cobalt Formate Complexes of Oxidation States +II and +I

The syntheses of the (tripod)cobalt formate complexes [(tri‐pod)Co(O2CH)]n+ (1/1+; n = 0, 1; tripod = CH3C(CH2PPh2)3) are presented. The structures are established by X‐ray analyses as well as the usual analytical techniques.
Thermally Stable Self‐assembling Open‐Frameworks: Isostructural Cs+ and (CH3)4N+ Iron Germanium Sulfides
Authors: Bowes Carol L. , Lough Alan J. , Malek Andrzej , Ozin Geoffrey A. , Petrov Srebri , Young David
Published: July 2007

Here we report on investigations that have revealed for the first time that the Cs+ ion templates the same metal germanium sulfide open‐framework as (CH3)4N+ (TMA+), and that metal complexing agents enhance crystal size by at least two orders of magnitude. The synthesis, structures and thermal properties of Cs2FeGe4S10 ·× H2O and TMA2FeGe4S10 are also described. Both have 3D zinc blende‐type open‐framework structures. These materials have the same connectivity as TMA2MnGe4S10. The tetrahedral sites in the lattice are alternately substituted by pseudo‐tetrahedral Fe2+ and adamantanoid Ge4S104‐ building blocks, covalently linked together by Fe(μ‐S)Ge bridge bonds, to give a tetragonal unit cell. The charge‐balance of the anionic framework [Fe‐Ge4S10]2‐ is maintained by either Cs+ or TMA+ ions in the cavity spaces. Synthesis of these materials demonstrates an interesting example of a self‐assembly process in which a 3D framework is built from molecular precursors. Water adsorption‐desorption cycling from room temperature to 200 °C reveals framework flexibility between larger and smaller tetragonal unit cell 14 isotypes. The compound TMA2FeGe4S10 is stable in nitrogen at 350 °C and under vacuum at 450 °C. The corresponding temperatures for Cs2FeGe4S10 are 530 °C and 630°C; it is stable on cooling to room temperature under vacuum, and after subsequent exposure to air. Six hundred thirty degrees celsius is the highest recorded temperature at which the integrity of a non‐oxide framework has been maintained. The framework stability and flexibility of “all‐inorganic” Cs2FeGe4S10 provides an encouraging example for researchers interested in developing sulfide‐based framework materials with practical applications.
Cäsium‐Fluor‐Vierringe als Strukturmotiv in Cäsium‐Triorganofluorometallaten der Gruppe 13
Authors: Werner Bert , Neumüller Bernhard
Published: July 2007

Cesium‐Fluorine Four‐Membered Rings as Structural Motive in Cesium Triorganofluoro Metalates of Group 13

The reactions of AlMe3, GaMe3, and InMe3 with CsF in acetonitrile furnish the corresponding trimethylfluoro metalates Cs[Me3MF] (1: M = Al, 2: M = Ga, 3: M = In). The salt‐like compounds 1 – 3 were characterized by NMR, IR, and MS techniques as well as by X‐ray structure analysis. Cs2F2 four‐membered rings are the structure‐dominating units in all three compounds. Compound 1 consists of puckered layers of weakly associated Cs2F2 rings parallel to (100), while the four‐membered rings in 2 form infinite ladder‐type chains. The Cs–F rings in 3 build up a heterocubane with a Cs4F4 core by ring stacking.
The Chemistry of ArsenicCarbon Multiple Bonds: Arsaalkenes and Arsaalkynes
Authors: Weber Lothar
Published: July 2007

The present article gives an account of the synthesis and structure as well as the spectroscopic and chemical properties of arsaalkenes R1AsCR2R3 and arsaalkynes RCAs. Arsaalkenes are significantly less stable and more reactive than the corresponding phosphaalkenes. Only one kinetically stabilized arsaalkyne has been described so far.
(tert‐Butoxy)aluminium and ‐gallium Hydrides
Authors: Veith Michael , Faber Stefan , Wolfanger Holger , Huch Volker
Published: July 2007

The crystal structures obtained by X‐ray methods of (tert‐ butoxy)alane and ‐gallane (tBuOMH2) are isotypic and are composed of discrete centrosymmetric dimers. The dimers arise from almost symmetrical AlOAl [1.810(3), 1.815(3) Å] and GaOGa [1.902(9), 1.908(9) Å] bridges forming a central rhombohedral four membered M2O2 cycle [OAlO 81.0(2)°, OGaO 78.6(5)°] with the metallic atoms in a distorted tetrahedral environment. When one of the hydride ligands on the metals is further substituted by tert‐butoxy, the formation of (tBuO)2AlH and (tBuO)2 GaH is observed. These two compounds crystallize in different lattices and space groups, but they are nevertheless very similar in their structure: the centrosymmetric M2O2 cycle is maintained [AlO 1.817(3), 1.817(3) Å; GaO 1.904(4), 1.907(4) Å] As expected, the terminal Al–O [1.675(3) Å] and GaO [1.783(4) Å] distances are considerably shorter than the bridging ones.