bluuebunny/crossref_metadata_2025_split huggingface dataset:
Triferriothioxophosphoranes: First Structural Characterization of a μ3‐P=S Complex
Authors: Lorenz Ingo‐Peter , Pohl Wolfgang , Polborn Kurt 
Published: July 2007

AbstractThe P‐H‐functional triferriophosphonium salts [{CpFe‐(CO)2}3PH]2FeCl4 (1) and [{μ‐CO(CpFeCO)2}{CpFe‐(CO)2}PH]2FeCl4 (4) are easily deprotonated by DBU to the corresponding unstable triferriophosphanes 2, 5, which subsequently are oxidized by sulfur to the triferriophosphane sulfides {CpFe(CO)2}3P=S (3) and {μ‐CO(CpFeCO)2}{CpFe‐(CO)2}P=S (6), respectively. The photolysis of 3 results only in its decomposition by elimination of [CpFe(CO)2]2, whereas the photolysis of 6 cleaves off one CO ligand to give the new spiro compound (CpFeCO)(μ‐η2‐PS){μ‐CO(CpFeCO)2} (7), where the P=S unit is η2‐bonded to the 15‐electron CpFeCO fragment, and the phosphorus atom bridges two 17‐electron fragments. Compound 7 shows a new coordination mode of the PS unit where sulfur is also bound to one of the metal atoms. Compounds 6 and 7 can be regarded as first examples of a new class of PS complexes of transition metals. All compounds were characterized by IR, 31P{1H}‐ and 13C{1H}‐NMR spectroscopy as well as mass spectrometry; for 6 the X‐ray analytical data are given.
2‐(2,4‐Di‐tert‐butylphenyl)‐1,1‐bis(trimethylsilyl)silene and 2‐(2,4,6‐Tri‐tert‐butylphenyl)‐1,1‐bis(trimethylsilyl)silene – Two New Sterically Protected but Still Unstable Silaethenes
Authors: Luderer Frank , Reinke Helmut , Oehme Hartmut 
Published: July 2007

Abstract(2,4‐Di‐tert‐butylphenyl)tris(trimethylsilyl)silylmethanol (1a), prepared by the reaction of tris(trimethylsilyl)silylmagnesium bromide with 2,4‐di‐tert‐butylbenzaldehyde, was deproto‐nated by treatment with methyllithium in ether at –78°C to give the transient 2‐(2,4‐di‐tert‐butylphenyl)‐1,1‐bis(trimeth‐ylsilyl)silene (3a), which dimerizes in a head‐to‐head fashion with the formation of (E)‐/(Z)‐3,4‐bis(2,4‐di‐tert‐butylphenyl)‐1,1,2,2‐tetrakis(trimethylsilyl)‐1,2‐disilacyclobutane (5). Besides 5 an unstable compound 4 was obtained, which was preliminarly assigned as 5,7‐di‐tert‐butyl‐1‐(2,4‐di‐tert‐bu‐tylphenyl) ‐1,2,3,8a‐tetrahydro‐2,2,3,3‐tetrakis(trimeth‐ylsilyl)‐1,2‐disilanaphthalene (4), the formal [2 + 4] cyclodimer of 3a. Compound 4 gradually decomposes to give (E)‐/(Z)‐5, and is considered to be the kinetically preferred dimer of 3a, which is converted into the thermodynamically stable 5. 2,4,6‐Tri‐tert‐butylbenzaldehyde reacts with tris(tri‐methylsilyl)silyllithium resulting in the formation of 6,8‐di‐tert‐butyl‐1,2,3,4‐tetrahydro‐4,4‐dimethyl‐2,2‐ bis(trimethylsilyl)‐2‐silanaphthalene (6). Compound 6 is the product of the insertion of the Si=C bond into the C–H bond of an o‐tert‐butyl group of the intermediate 2‐(2,4,6‐tri‐tert‐butylphenyl)‐1,1‐bis(trimethylsilyl)silene (3b), which despite extreme steric shielding proved to be still unstable. For compounds (Z)‐5 and 6 the results of the X‐ray analyses are given.
Syntheses and Structures of 13‐Substituted 1,5,9‐Triazatricyclo[7.3.1.05,13]‐tridecanes and Their Copper(II) Chloride Complexes
Authors: Köhn Randolf D. , Seifert Guido , Kociok‐Köhn Gabriele 
Published: July 2007

AbstractThe orthoamides2a, b(R = Ph and PhCH2) have been prepared by alkylation of the guanidinium salt4+BPh4−with PhNa and PhCH2Na, respectively. The crystal structures of the two orthoamides have been determined by X‐ray crystallography. Their reaction with CuCl2gives 1:1 complexes. The crystal structure of the complex with2ashows a square planar geometry around the copper atom with η2‐2aand two chlorides and weak interactions two the third nitrogen atom and a C–H bond of2ain the axial positions.
Charge‐Transfer Complexes of Metal Dithiolenes, XXII. Bis(maleonitriledithiolato)oxomolybdate(IV) – Bipyridinium Ion Pairs
Authors: Götz Brigitte , Knoch Falk , Kisch Horst 
Published: July 2007

AbstractThe oxomolybdenum complex (NBu4)2[MoO(mnt)2] (mnt2− = maleonitriledithiolate) 2 was characterized by X‐ray structural analysis. By metathetic reaction with bipyridinium salts AX2 ion pair charge‐transfer complexes of composition {A2+[MoO(mnt)2]2−} were isolated. Although a plot of the energy of the ion pair charge‐transfer band vs. the driving force of electron transfer from the dianion to the dication afforded a straight line, the slope of 0.45 suggests significant deviations from the Hush‐Marcus model. When bis(2‐hy‐droxyethyl)viologen is the acceptor, in addition to the supra‐molecular charge‐transfer interaction, hydrogen bridges are introduced between the two components as indicated by IR and X‐ray diffraction analysis.
Coordination Chemistry of Dimethylgold Halides with Bidentate Phosphorus and Arsenic Ligands – Revisited
Authors: Paul Martin , Schmidbaur Hubert 
Published: July 2007

AbstractDimethylgold(III) chloride and bromide, (Me2AuX)2, react with bis(diphenylphosphanyl)methane (dppm, molar ratio 1:2) to give the P‐monohapto complexes cis‐Me2AuX(dppm) (1a, b) in quantitative yields. The products are readily oxidized by air to yield the P‐hapto P′‐monoxides 2a, b. Treatment of 1a, b with AgNO3 affords an ionic nitrate [Me2Au(dppm)]2 [NO3−]2 (1c), which contains a dinuclear cation. A mixed bromide/nitrate (from 1b and half the equivalent amount of AgNO3) is thermally unstable and undergoes elimination of ethane to give an ionic tetranuclear gold(I) complex [(dppm)4Au4Br2]2+ [NO3−]2 (3b). – Treatment of (Me2AuCl)2 with CH2(AsPh2)2 (dpam, molar ratio 1:2) gives cis‐Me2‐AuCl(dpam) (1d), the arsenic analog of 1a, which is not sensitive to oxygen. – The reaction of bis(diphenylphosphanyl)‐amine (dppa) yields 1:1 P‐monohapto adducts Me2. AuX(dppa), which are in equilibrium with ionic chelated systems Me2Au(dppa)+ X− (1e, f). Complex 1e is readily oxidized by air to the P‐hapto P′‐monoxide cis complex 2e. Treatment of 1e with AgNO3 gives the ionic nitrate Me2. Au(dppa)+ NO3− (1g). – All compounds were identified by standard analytical and spectroscopic techniques. The crystal structures of 2a, 3b, 1d, and 2e were determined by single‐crystal X‐ray diffraction studies.
Kinetic Investigations of the Hydrogenation of Diolefin Ligands in Catalyst Precursors for the Asymmetric Reduction of Prochiral Olefins, II[1]
Authors: Heller Detlef , Borns Susanne , Baumann Wolfgang , Selke Rüdiger 
Published: July 2007

AbstractAsymmetric hydrogenations of prochiral olefines by means of chiral rhodium(I) complexes of the type [Rh(L)(PP*)]A (L = COD, [(Z,Z)‐cycloocta‐1,5‐diene], or NBD (norborna‐2;5‐diene), PP* = chiral bisphosphane forming seven‐membered chelate rings, A = anion like BF4−) are often associated with induction periods caused by partial blocking of the catalyst. NBD complexes are hydrogenated faster than the corresponding COD complexes. Catalytic hydrogenation of COD/NBD mixtures and the determination of the ratio of the Michaelis constants showed that the steady‐state concentration of the COD complex under hydrogen is higher than that of the NBD complex. However, under argon the NBD complex predominates owing to its higher thermodynamic stability compared with that of the COD complex as determined by 31P‐NMR spectoscopy. This complete reversion of the ther‐modynamically determined ratios of COD to NBD complex concentration under hydrogenation conditions was proven by means of UV/Vis spectroscopy.
Alkali Metal Polyphosphides in Low Dimensions: Synthesis and Structure of [(CH3)4N]2RbP7(NH3) and [(C2H5)4N]Cs2P11
Authors: Korber Nikolaus , von Schnering Hans Georg 
Published: July 2007

AbstractPartial exchange of the alkali metal ions for tetraalkylammonium cations of Rb3P7 and Cs3P11 in liquid ammonia results in the formation of [(CH3)4N]2RbP7(NH3) (1) and [(C2H5)4N]Cs2P11 (2). The crystal structures reveal the existence of one‐dimensional [RbP7]2− chains in the former and two‐dimensional [Cs2P11]− layers in the latter compound. The nortricyclane cage in 1 is distorted by one‐sided coordination to the Rb ions in a manner that can be related to the valence tautomerism of the free P73− anion.
On the Synthesis of Sulfoxonium Ylides: New Aspects of the Chemistry of 1,3‐Dithietane 1,1,3,3‐Tetraoxide and 1,3,5‐Trithiane 1,1,3,3,5,5‐Hexaoxide
Authors: Sundermeyer Wolfgang , Walch Andreas 
Published: July 2007

AbstractSulfoxonium ylides 3a‐h were synthesized by silylation of the cyclic methylene disulfones 1,3‐dithietane 1,1,3,3‐tetraoxide (1) and 1,3,5‐trithiane 1,1,3,3,5,5‐hexaoxide (4) with the silylating agents silyl nonafluorobutanesulfonates. The structure and constitution of the ylides were established with 1H‐NMR, 13C‐NMR, 29Si‐NMR spectroscopy, mass spectrometry, and elemental analysis. On the route to the sulfoxonium ylides a new class of unsaturated disulfenes 7, 8, 12, 13 of 1 and 4 were synthesized via Knoevenagel and substitution reactions. Dianions of newly formed alkyl disulfenes 16a, b, e, f, and the trianion 17 were prepared and characterized by 1H‐NMR and 13C‐NMR spectroscopy and compared with the results of the ylides.
Transition Metal‐Substituted Arsaalkenes, II. Synthesis, Structure and Reactivity of the Arsaalkenes RAs=C(NMe2)2 [R = Me3Si, (η5‐C5Me5)(CO)2Fe] and the 1,2‐Dihydroarsete (η5‐C5Me5)(CO)2‐Fe
Authors: Weber Lothar , Kaminski Olaf , Stammler Hans‐Georg , Neumann Beate 
Published: July 2007

AbstractReaction of equimolar amounts of thiuronium salt [(Me2N)2C‐SMe]I (1, with LiAs(SiMe3)2 · 2 THF (2) afforded arsaalkene Me3SiAs=C(NMe2)2 (3). Combination of 3 with (η5‐C5Me5)(CO)2 FeBr led to the formation of (η5‐C5Me5)(CO)2‐FeAs=C(NMe2)2 (4). Reaction of the latter with dimethyl fumarate gave the 1,2‐dihydroarsete (η5‐C5Me5)(CO)2‐Fe (6). Compounds 3, 4, and 6 were characterized by means of spectroscopy (IR, 1H, 13C{1H}, 29Si{1H} NMR and mass spectrometry). The molecular structures of 4 and 6 were determined by X‐ray diffraction analysis.
1‐Bromo‐3,5‐bis(trifluoromethyl)benzene: A Versatile Starting Material for Organometallic Synthesis
Authors: Porwisiak Jacek , Schlosser Manfred 
Published: July 2007

Abstract1‐Bromo‐3,5‐bis(trifluoromethyl)benzene (1) can be selectively prepared by treatment of 1,3‐bis(fluoromethyl)benzene with N,N'‐dibromo‐5,5‐dimethylhydantoin in strongly acidic media. A number of synthetically useful reactions via 3,5‐bis(trifluoromethyl)phenylmagnesium, ‐lithium, and ‐copper intermediates were accomplished.
Lithiierte Phosphanimine. Synthese und Kristallstrukturen von [LiCH2PMe2NSiMe3]4 und [LiCMe2P(iPr)2NSiMe3]2
Authors: Müller Anita , Neumüller Bernhard , Dehnicke Kurt 
Published: July 2007

Lithiated Phosphane Imines. Synthesis and Crystal Structures of [LiCH2PMe2NSiMe3]4 and [LiCMe2P(iPr)2NSiMe3]2The title compounds were prepared by the reaction of Me3‐SiNPMe3 and Me3SiNP(iPr)3, respectively, with n‐Butylli‐thium at 20°C in n‐hexane solution. They form white, moisture‐ and oxygen‐sensitive crystals, which were characterized by IR spectroscopy and by crystal structure determinations. – [LiCH2PMe2NSiMe3]4 (1) forms a Li4 tetrahedron, the faces of which are capped with CH2 groups with average Li‐C distances of 233 and 251 pm, while the nitrogen atoms occupy the corners of the Li4 tetrahedron. – [LiCMe2P(iPr)2N‐SiMe3]2 (2) forms molecules of symmetry C2 in which the lithium atoms have coordination number three by two carbon atoms and one nitrogen atom with Li‐C distances of 215.2 and 237.9 pm and Li‐N of 192.8 pm.
Phosphorus Analogs of Bipyridines: Their Synthesis and Coordination Chemistry
Authors: Mathey François , Le Floch Pascal 
Published: July 2007

AbstractThe synthesis and coordination chemistry of 2‐(2‐pyridyl)‐phosphinines and 2,2′‐biphosphinines are reviewed. A noteworthy series of homoleptic complexes of 4,4′,5,5′‐tetramethyl‐2,2′‐biphosphinine (tmbp) with Cr(0), Mo(0), Wo(0) and Ni(0) are described. A [Cu(bpy)(tmbp)]+ cationic polymer has been characterized by X‐ray analysis. Ruthenium, manganese and rhenium chelates were also obtained. With Mn2(CO)10, a (tmbp)‐Mn2(CO)6 complex is formed where tmbp acts as an eight electron donor.
Synthesis and Characterization of Titanium Complexes Containing Potentially Tridentate Amido‐cyclopentadienyl Ligands
Authors: Okuda Jun , Du Plooy Karen E. , Massa Werner , Kang Hak‐chul , Rose Ulrich 
Published: July 2007

AbstractTwo new titanium complexes of the general type Ti(η5:η1‐C5H4SiMe2NCH2CH2X)Cl2 (X = NMe2 OMe), containing a tridentate ligand, were prepared by reaction of Ti(η5‐C5H4SiMe2Cl)Cl3 with the lithium amide Li(NHCH2CH2X) (X = NMe2, OMe). The 1HNMR chemical shifts for the protons of the ethylene link were found to vary considerably as a function of the temperature, indicating the presence of an equilibrium between the tri‐ and bidentate bonding mode of the ligand. A single‐crystal X‐ray structural analysis of Ti(η5:η1C5H4SiMe2NCH2CH2OMe)Cl2 revealed that the methoxy function is not intramolecularly coordinated in the solid state.
A Study on Electronic Interaction Between two [2.2]Metacyclophane Systems Connected with a CC Bond: Preparation, Structure and Complexation of (E)‐ and (Z)‐8,8′‐(Ethene‐1,2‐diyl)bis(5‐tert‐butyl[2.2]metacyclophane)
Authors: Ishi‐I Tsutomu , Sawada Tsuyoshi , Mataka Shuntaro , Tashiro Masashi , Thiemann Thies 
Published: July 2007

Abstract(E)‐8,8′‐(Ethene‐1,2‐diyl)bis(5‐tert‐butyl[2.2]metacyclo‐phane) (2) was obtained from a McMurry reaction of 5‐tert‐butyl‐8‐formyl[2.2]metacyclophane (1). Irradiation of 2 with a high‐pressure mercury lamp gave the corresponding (Z) isomer 3. X‐ray crystallographic analyses of 2 and 3 show a certain degree of twisting of the bond connecting the meta‐cyclophane unit and the central π system due to steric crowding. UV spectra of 2 and 3 and of the charge‐transfer complexes [2/TCNE] and [3/TCNE] allow for a discussion of π‐π interaction between the central stilbene subunit and the outer benzene rings of the metacyclophane units. Bis[2.2]meta‐cyclophanes 2 and 3 reacted regioselectively with hexacar‐bonylchromium on the outer benzene rings giving 1:1 and 1:2 complexes 9–14 with tricarbonylchromium. No 1:3 and 1:4 complexes formed due to steric restrictions. Analysis of UV spectral data of the complexed [2.2]metacyclophanes was performed for an indication of π‐π interactions in the complexes.
Preparation, Characterisation and Reactivity of Neutral Mono‐η4‐oxadiene Complexes of Molybdenum and Tungsten Containing Bidentate Donor Ligands
Authors: Schmidt Thomas , Bienewald Frank , Goddard Richard 
Published: July 2007

AbstractNeutral molybdenum and tungsten complexes containing only one η4‐coordinated 1‐oxa‐1,3‐diene ligand are obtained diastereospecifically from the reaction of the corresponding dicarbonylbis(oxadiene) complexes with bidentate donor ligands capable of forming five‐membered ring chelates. Thus, dicarbonylbis[η4‐(R)‐(+)‐pinocarvone]metal complexes react with 1,2‐bis(dimethylphosphanyl)ethane (dmpe) or N,N,N′,N′‐tetramethylethylenediamine (tmeda) to give the mono(oxadiene) compounds 1 – 4 in 45–95% yield. The molecular structure of the dmpe‐tungsten complex 3 was determined by X‐ray structural analysis Spectroscopic data indicate that an effective transfer of electron density from the donor atoms occurs. This is also reflected in a decreased reactivity of the carbonyl ligands in the mono(oxadiene) complexes towards nucleophilic alkylation. As a result, the selectivity in the alkylation (a formal “Umpolung” reaction) of anionic intermediates generated from 2 and methyllithium with carbon electrophiles is greatly improved, allowing access to alkylation products, e.g. 5, that are otherwise difficult to obtain.
Complexes with S‐Donor Ligands, 4. Mono‐ and Di‐Homo‐ and ‐Hetero‐Nuclear Gold(I), Silver(I), and Palladium(II) Complexes with 2‐(Methylthio)pyridine, Pyridine‐2(1H)‐thione, and Benzoxazole‐2(3H)‐thione. Some Examples of the Use of Complexes as Ligands
Authors: Vicente José , Chicote María‐teresa , Rubio Concepción 
Published: July 2007

AbstractAgClO4 reacts with bidentate ligands 2‐(methylthio)pyridine (SMepy) or complexes PPN[Au(Spy)2] [PPN = N(PPh3)2, HSpy = pyridine‐2(1H)‐thione) or PPN[Au(Sbz)2] (HSbz = benzoxazole‐2(3H)‐thione), themselves acting as ligands, to give dinuclear complexes [Ag2(μ‐SMepy)2](ClO4)2 (1), [AgAu(μ‐Spy)2] (2), or [AgAu(μ‐Sbz)2] (3), respectively. By treating 1 with [AuCl(tht)] (tht = tetrahydrothiophene), [Au(SMepy)(tht)]ClO4 (4) is obtained which, in turn, reacts with SMepy to give [Au(SMepy)2]ClO4 (5). Similarly, [PdCl2(NCPh)2] reacts with SMepy in 1:1 molar ratio to give [Pd2Cl2(μ‐Cl)2(SMepy)2] (6) which reacts with SMepy in 1:2 molar ratio to give [PdCl2(SMepy)2] (7). On the other hand, HSpy reacts with Ag2CO3 to give [Ag2(μ‐Spy)2] (8), and (SMepyH)ClO4 reacts with [Au(acac)PPh3] (acacH = acetyl‐acetone) to give [Au(SMepy)PPh3]ClO4 (9).
Zinc Complexes of Amino Acids and Peptides, 6. Zinc Complexes of Oligopeptides Containing Histidine at Both Termini
Authors: Förster Martin , Brasack Ingo , Duhme Anne‐Kathrin , Nolting Hans‐Friedrich , Vahrenkamp Heinrich 
Published: July 2007

AbstractOne tripeptide, five tetrapeptides, and one pentapeptide, all containing His–Xn–His sequences and being blocked at the N and C termini with acyl and amide functions, respectively, were synthesized by solid‐phase methods. With one exception their reaction with various zinc salts led to the precipitation of 1:1 (zinc/peptide) complexes. Analytically pure compounds were obtained from zinc tetrafluoroborate and His–Gly–His (1), from zinc chloride (resp. bromide) and His–Gly –Gly–His (2), His–Ala–Gly–His (3), His–Leu–Gly–His (4), His–Pro–Gly–His (5), and His–Pro–Asn–His (6) as well as from zinc sulfate and His–Leu–Gly–His (4) and His–Ala–Pro–Gly–His (7).1H‐NMR data, when available, indicate the coordination of both histidine units to zinc in all cases. The low solubility of the complexes points to their polymeric nature. The only 1:2 (zinc/peptide) complex in this series was obtained from zinc perchlorate and His–Gly–Gly–His (2). An EXAFS study revealed that it contains zinc symmetrically coordinated by four histidine imidazole ligands. Based on the available information it is proposed that all complexes are one‐dimensional polymers containg [–Zn–His–Xn–His–Zn–]xbackbones.
Novel trialkylstibane iridium(I) and iridium(III) complexes including the x‐ray crystal structure of five‐Coordinate [IrCl(C2H4)2(SbiPr3)2]
Authors: Werner Helmut , Ortmann Dagmara A. , Gevert Olaf 
Published: July 2007

AbstractThe reaction of [IrCl(C8H14)2]2 (2) with SbiPr3 in the presence of H2 yields the dihydridoiridium(III) complex cis,mer‐[IrH2Cl(SbiPr3)3] (3) which on treatment with CO and with HCCR (R = Ph, CO2Me) affords the octahedral derivatives [IrH2Cl(CO)(SbiPr3)2] (4) and [IrHCl(CCR)(SbiPr3)3] (5, 6), respectively. The stibane ligand trans to hydride in 5 and 6 is rather labile and, therefore, 5 and 6 react with pyridine to give [IrHCl(CCR)(py)(SbiPr3)2] (7, 8). Five‐coordinate bis‐(stibane)iridium(I) complexes [IrCl(C2H4)2(SbR3)2] (10–12) were prepared from [IrCl(C2H4)2]2 (9) and four equiv. of SbR3 (R = iPr, Me, Ph). The X‐ray crystal structural analysis of 10 reveals a distorted trigonal‐bipyramidal geometry around the metal center with one stibane ligand and the two olefinic ligands in the equatorial plane. Compound 10 reacts with NaC5H5 to yield [C5H5Ir(C2H4)(SbiPr3)] (13) and with different alkynes by partial or complete displacement of the ethene ligands to give trans‐[IrCl(PhCCPh)(SbiPr3)2] (14), [IrHCl(CCTol)(C2H4)(SbiPr3)2] (15), and trans‐[IrCl‐{CC(SiMe3)R}(SbiPr3)2] (16, 17), respectively.
The chemistry of metallacyclic alkenylcarbene complexes, 3. CC bond formation with carbon nucleophiles. stereoselective dienylation of lithium enolates and cuprates and a novel cascade synthesis of highly substituted cyclopentenones from lithium acetylides
Authors: Böhmer Jutta , Förtsch Walter , Hampel Frank , Schobert Rainer 
Published: July 2007

AbstractThe cationic ferracyclic carbene complexes 1 react with carbon nucleophiles like lithium enolates and organocuprates to give the corresponding 4‐substituted 1, (3E)‐diene tricarbonyl‐iron complexes 6 and 9. The reaction is thought to proceed by initial attack on the allyl terminus and subsequent ferra Claisen‐Ireland rearrangement of the intermediate (η2 alkene)carbene complex 4. This rationale is supported by the isolation and characterisation of analogous aminooxocarbene derivatives 8. With sterically demanding enolates products 6 are formed in diastereomeric ratios of up to 90:10, thus demonstrating the inductive power of the chiral metallacycle in 1. Lithium acetylides as carbon nucleophiles react with 1 according to a novel cascade to give regio‐ and stereospecifically 2,5,5‐trisubstituted‐cyclopentenones 10 suggesting a concerted formation of four CC bonds together with a CO insertion and a formal carbene transfer step.
A New Reagent for Nucleophilic Aminomethylation: Doubly Lithiated Bis(dimethylamino)methane and Its Use for the Synthesis of Si,N‐Heterocycles
Authors: Karsch Hans H. 
Published: July 2007

AbstractThe aminal Me2NCH2NMe2 is doubly metalated by LitBu to give LiCH2N(Me)CH2N(Me)CH2Li, which reacts with chlorosilanes to afford the respective silylated species, including the six‐membered heterocycle Me2SiCH2N(Me)CH2N(Me)‐CH2 and the spiroheterocycle Si[CH2N(Me)CH2N(Me)CH2]2.
On the Chemistry of Gallium, 8. Synthesis and Structure of [Tris(trimethylsilyl)silyl]‐Substituted Gallanes and Gallates
Authors: Linti Gerald , Frey Ronald , Köstler Wolfgang , Urban Horst 
Published: July 2007

AbstractReaction of lithium tris(trimethylsilyl)silanide · 3 THF with R2GaCl (R = 2,2,6,6‐tetramethylpiperidino, Me, Cl) yields tmp2GaSi(SiMe3)3 (3) and R2Ga(THF)Si(SiMe3)3 (R = Me, Cl) (7, 9). Both gallium nitrogen bonds in 3 are cleaved by protic reagents. Depending on the acidity of these agents, either oligomeric gallanes [(RO)2GaSi(SiMe3)3]n (R = Et, H, n = 2, 3) (11, 12) or tetramethylpiperidinium gallates [X3GaSi‐(SiMe3)3]– (X = OPh, Cl) (13, 14) are formed. Hydroxide 11 adds lithium hydroxide to afford the mixed lithium gallium hydroxide 15. Single‐crystal X‐ray diffraction studies confirm the suggested constitutions. The gallium‐silicon bond can adopt values between 236 and 247 pm. Here electronic influences of the substituents on the gallium center are of great importance as well as their steric demand. This is underlined by quantum chemical calculations on the ab initio (SCF) level.
cis‐ and trans‐Dimolybdenum(II) Complexes with Asymmetrically 2,7‐Disubstituted Naphthyridines as Bridging Ligands
Authors: Mintert Markus , Sheldrick William S. 
Published: July 2007

AbstractTreatment of [Mo(CO)6] with Hmamnp (2‐acetamido‐7‐methyl‐1,8‐naphthyridine) in diglyme at 100°C affords the mononuclear complex [Mo(CO)4(Hmamnp)] 1, an intermediate product on the reaction pathway to tetrasubstituted species of the type [Mo2L4]. A disubstituted intermediate product cis‐[Mo2(mphamnp)2(OAc)2] 2 (Hmphamnp) (2‐acetamido‐5‐methyl‐7‐phenyl‐1,8‐naphthyridine) may be isolated from the reaction of [Mo2(OAc)4] with mphamnp– in THF. The relative stabilisation of such products is a result of the steric demands of the coplanar 2‐acetamido substituents. 2 and the tetrasubstituted complexes trans‐[Mo2(mbznnp)4] 3 (Hmbznnp = 2‐benzylamino‐7‐methyl‐1,8‐naphthyridine), cis‐[Mo2(mphonp)4] 4, and trans‐[Mo2(mphonp)4] 5 (Hmphonp = 5‐methyl‐7‐phenyl‐1,8‐naphthyridin‐2‐one) all exhibit the electronically prefered μ‐N1,X2 bridging mode. Steric effects are responsible for the isolation of the unusual cis isomer 4.