Volume 69, Issue 11-12

5,11,17,23-Tetrakis(trimethylsilylethynyl)-25,26,27,28-tetra-n-propoxycalix[4]arene (1) was synthesised in two steps starting from 25,26,27,28-tetra-n-propoxycalix[4]arene, and the structure of 1 was determined by X-ray diffraction. Compound 1 was desilylated (K 2 CO 3 ) to give 5,11,17,23- tetrakis(ethynyl)-25,26,27,28-tetra-n-propoxycalix[4]arene (2), which was tetra-aurated under basic conditions (NaOEt, THF) with a series of phosphane-gold chlorides (o-Tol 3 PAuCl, Ph 3 PAuCl, Ph 2 MePAuCl, PhMe 2 PAuCl, Me 3 PAuCl, Cy 3 PAuCl, t-Bu 3 PAuCl) to afford in good to excellent yields the tetra-aurated tetraethynylcalix[4]arene species 3-9 in one step [with phosphane ligands o-Tol 3 P (3), Ph 3 P (4), Ph 2 MeP (5), PhMe 2 P (6), Me 3 P (7), Cy 3 P (8), t-Bu 3 P (9)]. All compounds were characterised by 1 H NMR and infrared spectroscopy, mass spectrometry and by elemental analyses, additionally 3, 4, 5, 8 and 9 by 13 C{ 1 H}, and 3-6, 8 and 9 by 31 P{ 1 H} NMR spectroscopy. The molecular structures of complexes 3 and 9 were determined by X-ray diffraction and show pinched-cone conformations, but neither intra- nor intermolecular attractive aurophilic Au···Au contacts. The acceptor ability of complexes 3 and 9 was investigated by complexation attempts with various phosphane-gold chlorides and xenon gas under pressure, but interactions could not be determined experimentally. The formation of a complex between xenon and gilded calix[4]arene could, however, be predicted for fluorine-substituted species and with very small phosphane ligands (PH 3 ) on the basis of quantum-chemical calculations; the energy of formation is 9:6 kJ mol -1 . The crystal structure of Ph 2 MePAuCl was also determined and shows Au···Au-bonded dimers.

When Au(I) is provided with endocyclic soft thioether or endocyclic hard amine, endocyclic borderline imine and exocyclic hard amine coordination sites, the softer borderline endocyclic imine coordination site is favored. This is demonstrated by the synthesis and structural characterization (IR, MS, 1 H, 13 C and 31 P NMR experiments and single-crystal X-ray diffraction analysis) of 2-aminoazole (2-amino-4-methylthiazole, 2-aminobenzothiazole and 2- aminobenzimidazole) complexes of [AuPPh 3 ] + (1-3). An unusual ring opening is observed for the reaction of 2-aminothiazoline with [Au(NO 3 )PPh 3 ] yielding μ 2 -(2-mercapto-ethyl-cyanamide- k,S)bis(triphenylphosphine)gold(I) nitrate (4). Reactions of 2-aminoazoles with Au(C 6 F 5 )THT (THT=tetrahydrothiophene) yield [Au(C 6 F 5 ) 2 ] - stabilized by various cations. The formation of Au(2-aminothiazoline)C 6 F 5 is again the exception

The first enantioselective synthesis of a photoreactive (R)-β-phenylalanine is described. In the key step, m-diazirinyl-substituted benzaldehyde is converted to a chiral sulfinimine in a Ti(OEt) 4 - mediated reaction, followed by diastereoselective enolate addition. The absolute configuration of photo (R)-β-phenylalanine was confirmed by Mosher analysis. The photo amino acid proved to be thermally stable under standard laboratory conditions. Irradiation in toluene afforded cycloheptatriene=norcaradiene valence tautomers, together with carbene benzylation. Quantumchemical calculations indicate a small triplet-singlet gap.

The lanthanum-rich antimonide La 2 NiSb was synthesized by annealing a cold-pressed pellet of the elements in a sealed silica glas tube at 1120 K. La 2 NiSb was characterized by powder and single-crystal X-ray diffraction: ordered Bi 3 Ni type, Pnma, Z =4, a=825.6(3), b=452.2(2), c=1195.5(4) pm, wR=0.0695, 856 F 2 values, 26 variables. The nickel atoms form infinite zigzag chains (259 pm Ni-Ni) with trigonal-prismatic lanthanum coordination for each nickel atom. The antimony atoms cap the rectangular faces of the lanthanum prisms (336 pm La-Sb) and thereby coordinate also the nickel atoms (271 pm Ni-Sb). These rods run parallel to the b axis and form a herringbone pattern, similar to the FeB-type structure of GdNi. Although metallic conductivity is expected for La 2 NiSb from DFT-based band structure calculations, the real-space bonding analysis shows prominent localization of electrons on antimonide anions and positively charged lanthanum cations. The chain substructure is strongly bonded by polar covalent Ni-Sb and multicenter Ni-Ni interactions. The nickel atoms, which are involved in multicenter bonding with adjacent nickel and lanthanum atoms, provide a conductivity pathway along the prismatic strands. 121 Sb Mössbauer spectroscopic data at 78 K show a single signal at an isomer shift of -7.62(3)mms -1 , supporting the antimonide character. La 2 NiSb shows weak paramagnetism with a susceptibility of 2.5 x 10 -3 emu mol -1 at room temperature.

The gallium-rich intermetallic phases REPdGa 3 (RE=La, Ce, Pr, Nd, Sm, Eu) were obtained by arc-melting of the elements and subsequent annealing for crystal growth. The samples were studied by X-ray diffraction on powders and single crystals. The structures of three crystals were refined from X-ray diffractometer data: SrPdGa 3 type, Cmcm, a=634.3(1), b=1027.2(1), c=593.5(1) pm, wR=0.0621, 380 F 2 values, 20 variables for CePd 0:80(4) Ga 3:20(4) , a=635.9(1), b=1027.5(1), c=592.0(1) pm, wR=0.1035, 457 F 2 values, 19 variables for CePdGa 3 , and a=640.7(1), b=1038.2(1), c=593.7(1) pm, wR=0.0854, 489 F 2 values, 19 variables for EuPdGa 3 . The REPdGa 3 gallides are orthorhombic superstructure variants of the aristotype ThCr 2 Si 2 . The palladium and gallium atoms build up polyanionic [PdGa 3 ] δ- networks with Pd-Ga and Ga-Ga distances of 248 - 254 and 266 - 297 pm, respectively, in EuPdGa 3 . The rare earth atoms fill cavities within the polyanionic networks. They are coordinated by five palladium and twelve gallium atoms. Taking CePdGa 3 as an illustrative representative, the band structure calculations show largely dispersive itinerant s, p bands and little dispersive d (Pd) and f (Ce) bands, the latter crossing the Fermi level at large magnitude leading to magnetic instability in a spin-degenerate state and a subsequent antiferromagnetic ground state with a small moment of ±0.36 μ B on Ce. The bonding characteristics indicate a prevailing Ce-Ga bonding versus Pd-Ga and Ce-Pd. Temperature-dependent magnetic susceptibility and 151 Eu Mössbauer spectroscopic measurements point to stable trivalent lanthanum, cerium, praseodymium, and neodymium, but divalent europium. SmPdGa 3 shows intermediate valence. Antiferromagnetic ordering occurs at T N =5.1(5), 7.0(5), 6.3(5), 11.9(5), and 23.0(5) for RE=Ce, Pr, Nd, Sm, and Eu, respectively.

From an anhydrous pyridine extract of the binary Zintl phase K 12 Si 17 in the presence of the cation sequestering agent [2.2.2]crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) crystals of the compound [K([2.2.2]crypt)][C 10 H 8 N 2 ] have been isolated which contains the 4,4′- bipyridine radical monoanion. This compound was fully characterized by X-ray diffraction, 1 H, 13 C NMR, EPR, IR and UV=Vis spectroscopy

Single crystals of tetrazirconium copper heptaantimonide were obtained by arc-melting and annealing from the elements in ideal ratios including a 10% excess of Sb. The excess of Sb is needed to compensate for the evaporation loss during arc-melting synthesis. Zr 4 CuSb 7 crystallizes tetragonally, space group P4bm (no. 100) as a racemic twin. It adopts a unique structure that can be regarded as a composite of a PbClF unit and a layered, partially copper-substituted polyantimonide substructure. Zr 4 CuSb 7 represents a filling and substitution variant of the Hf 5 Sb 9 structure type. The copper atoms fill voids and partially replace antimony atoms in the 4.82 Sb net of the Hf 5 Sb 9 polyantimonide substructure to form a distorted 4 4 net in Zr 4 CuSb 7 . Structure relations to known zirconium-transition metal polyantimonides are given, and new structures are predicted based on these relations.

A copolymer composed of 2-acrylamido-2-methyl propane sulfonic acid (AMPS ® ) and N,Ndimethylacrylamide (NNDMA) as well as a forpolymer based on AMPS ® , NNDMA, 1-allyloxy- 2-hydroxy propane sulfonic acid (AHPS) and acrylic acid (AA) were synthesized and tested for their temperature stability. Both polymers were dissolved and aged in cement pore solution at temperatures between 100 and 220°C and 35 bar pressure, simulating conditions in actual well cementing. The influence of this high-temperature treatment on the fluid loss performance was assessed via highpressure filtration tests. Water retention capacity and adsorption of AMPS ® -co-NNDMA was found to decrease as a result of temperature-induced shrinkage of the stiff, linear polymer chain, as evidenced by dynamic light scattering (DLS) measurement of its hydrodynamic radius. Oppositely, the AHPS-based fluid loss additive did not exhibit coiling under high-temperature conditions. Therefore, its adsorption remained unaffected, and a stable fluid loss performance was observed

We report on the synthesis and crystal structure of the octaammine calcium(II) halides [Ca(NH 3 ) 8 ]Br 2 , and [Ca(NH 3 ) 8 ]I 2 , which were synthesized by the reaction of the respective calcium( II) halides with dry liquid ammonia. The compounds form colorless crystals which crystallize isotypically at 123 K with Z = 4 in the orthorhombic space group Pnma with a = 12:0478(3), b = 7:4406(2), c = 15:7216(4) Å, V = 1409:33(6) Å 3 for the bromide, and a = 12:1113(4), b = 7:7706(3), c = 16:7145(6) Å, V = 1573:0(1) Å 3 for the iodide. Instead of the expected tetragonal antiprism for the eightfold-coordinated Ca 2+ ions, we observed a coordination polyhedron best described as a twofold capped trigonal prism. After evaporation of the liquid ammonia and warming of [Ca(NH 3 ) 8 ]I 2 to room temperature, [Cu(NH 3 ) 6 ]I 2 was obtained as a colorless powder. The hexaammine calcium(II) iodide crystallizes isotypically to [Mn(NH 3 ) 6 ]I 2 (CaF 2 type) in the cubic space group Fm3̅m with a = 11:18580(6) Å, V = 1399:59(1) Å 3 , Z = 4 at 293 K

A series of salts containing the weakly coordinating cations (WCC) 1-butyl-3-methylimidazolium ([Bmim] + ), 1-butyl-2,3-dimethylimidazolium ([Bdmim] + ), 1-dodecyl-3-methylimidazolium ([C 12 mim] + ), tetrabutylphosphonium ([PBu 4 ] + ), tributyltetradecylphosphonium ([P 4;4;4;14 ] + ), tetrabutylammonium ([NBu 4 ] + ), and 1,1,3,3-tetramethylguanidium ([TMG] + ) and fluorinated tetraarylborate anions of the type [B(Ar F ) 4 ] (Ar F =C 6 F 5 , C 6 H 3 -3,5-(CF 3 ) 2 ) were synthesized and characterized. The influence of cations and anions on the physical properties of the obtained compounds was examined. In case of the compound [TMG][B(C 6 F 5 ) 4 ] hydrogen-fluorine contacts between cation and anion are present in the solid state. Owing to H···F contacts between hydrogen peroxide and the fluorine substituents of the anion and the resulting activation of H 2 O 2 in solution, the compound [P 4;4;4;14 ][B(C 6 H 3 -3,5-(CF 3 ) 2 ) 4 ] is applicable as an efficient mediator for the oxidation of sulfides to sulfoxides

The formation of self-assembled monolayers (SAMs) on Au(111) from solution has been investigated for two ionic iron(II) complexes of the type [Fe(L)](BF 4 ) 2 , where L is tripodal hexadentate and contains three thiocyanate anchor groups. The ligands (L1, L2; donor set: N 6 ) are obtained by Schiff base condensation of a tripodal triamine (L1: tris-(2-aminoethyl)amine, ‘tren’; L2: 1,1′,1″- trimethyl(thiophosphoryl)trihydrazide) with 5-(4-thiocyanatobutoxy) pyridine-2-carbaldehyde. Layers of the complexes adsorbed on Au(111) from methanol solution have been characterised using scanning tunnelling microscopy (STM), infrared reflectance absorbance (IRRAS), X-ray photoelectron (XPS) and UV=Vis reflectance spectroscopies, as well as ellipsometry. Complex [Fe(L1)](BF 4 ) 2 deposits intact on a gold surface and retains its optical addressability. Elaboration of this result may provide access to a new class of self-assembled layers, employing salt-like tripodal coordination compounds with thiocyanate anchors. The second complex, [Fe(L2)](BF 4 ) 2 , which contains a sulphur atom in the ligand backbone, is not sufficiently stable under the same conditions.

Treatment of tetraphenyldistibine (1) with terminal arylacetylenes, XC 6 H 5 C≡CH (2a-c, X=H, F, OMe), gave the corresponding anti-addition products (E)-aryl-1,2-bis(diphenylstibyl)ethenes 3a-c in 11 - 17% yields. A similar reaction of 1 with 1,4-diphenylbutadiyne provided (E)-1,4-diphenyl- 1,2-bis(diphenylstibyl)but-1-en-3-yne (3d) in 28% yield. X-Ray diffraction studies on crystals of 3a, 3b and 3d revealed a congested configuration around the ethylene core. The optical properties of the adducts 3a-d were examined by measuring UV absorption and photoluminescence spectra. Interestingly, 3d showed phosphorescence in the solid state, which was enhanced at low temperature.

The cyclohexyl-substituted imidazo[1,5-a]pyridin-2-ium hexafluorophosphate, 2a, has been prepared as precursor for the respective pyrido-annelated N-heterocyclic carbene. [(NHC) 2 Ag]PF 6 , 3, has been synthesized by the reaction of 2a with AgCl=KOH in dichloromethane (DCM). Unexpectedly, the reaction of 3 with (tht)AuBr yielded both (NHC)AuBr and [(NHC)Au(tht)]PF 6 which formed a 1 : 1 cocrystal (4a,b). The complexes are aggregated to infinite chains, which are governed by both π-π stacking and weak aurophilic interactions. Subsequent oxidation of the co-crystalline material with CsBr 3 gave (NHC)AuBr 3 , 5. All compounds were characterized by NMR spectroscopy, mass spectrometry and elemental analysis. Additionally, compounds 2a and 5 were investigated by electronic spectroscopy: 2a behaves like a typical aromatic compound exhibiting absorption and fluorescence bands attributable to π-π* transitions. The Au(III) complex 5 exhibits ligand-centered fluorescence at room temperature and both ligand-centered fluorescence and a weak phosphorescence at 77 K.

Our ongoing interest in the chemistry of polyfunctional Lewis acids has led us to investigate the reaction of the stibonium-borane [o-(Ph 2 MeSb)(Mes 2 B)C 6 H 4 ] + (1 + ) with cyanide and azide, two toxic anions. Both anions react with 1 + to afford the corresponding neutral complexes 1-CN and 1-N 3 . Structural and computational studies show that the coordinated anion interacts with both the boron and antimony atoms of the bidentate Lewis acid. While the azide complex features a typical κ 2 N 1 : N 1 bridging azide ligand, the cyanide complex possesses a cyanoborate moiety whose cyanide interacts side-on with the stibonium center. The Lewis acid-anion interactions observed in these complexes have also been studied computationally using the Natural Bond Orbital method

We report on the synthesis and structural characterisation of the bis(chelate) bis(pyrazolyl) pyridinylmethane iron(II) complexes [Fe{HC(Pz) 2 (Py)} 2 ][CF 3 CO 2 ] 2 , [Fe{HC(3-iPrPz)(5- iPrPz)(Py)} 2 ][CF 3 SO 3 ] 2 and [Fe{HC(3-iPrPz)(5-iPrPz)(Py)} 2 ][FeBr 4 ]Br·2C 4 H 8 O. During the synthesis of the latter ones, an isomerisation of the ligand is observed: the pyrazolyl substituent formally moves from the 3 to the 5 position. Since the donor competition between pyrazolyl and pyridinyl moieties is important for the coordination properties, we also studied the donor properties by density functional theory and natural bond orbital analysis (NBO). As a result, the pyridinyl donor is generally weaker than the pyrazolyl donor, but the pyrazolyl donor is heavily influenced by the alkyl substitution pattern. To confirm the low-spin state of the complexes, magnetic susceptibility measurements have been performed

By use of Re(CO) 5 FBF 3 the complexes with a single unsupported halide or pseudohalide bridge [Cp(OC) 2 Fe-X-Re(CO) 5 ] + BF 4 - (X=Cl, I, PPh 2 ), (OC) 5 M-X-Re(CO) 5 (M=Cr, W; X=Br, I, CN, NCS, SH), (OC)5W-N≡C-C[-C≡N-Re(CO) 5 ] 2 + BF 4 - , Cp(OC)(NC)Fe-C≡N-Re(CO) 5 , and [(OC) 5 Re-N 3 -Re(CO) 5 ] + BF 4 - have been synthesized.

When cymantrenyl-chlorosilanes [C 5 X 5-n (SiMe 2 Cl) n ]Mn(CO) 3 (X=H: n=4; X=Br: n= 3 - 5; 1a-d) come in contact with moist solvents, hydrolysis of two vicinal SiMe 2 Cl groups occurs with condensation to give 1,2,5-oxadisiloles. With n=3, only one oxadisilole ring is formed, while with n=4 or 5 the formation of one and=or two oxadisiloles is observed. Similar reactions occur, when 1a-d are treated with MeMgCl or MeOH. The molecular structures of two products, [C 5 Br 2 (SiMe 2 Cl)(Si 2 Me 4 O)]Mn(CO) 3 and [C 5 (SiMe 2 OMe)(Si 2 Me 4 O) 2 ]Mn(CO) 3 , are reported.

Cesium hydroxide, CsOH, was for the first time characterised on the basis of single-crystal data. The structure is isotypic to the one of the room-temperature modification of NaOH and can be derived from the NaCl structure type thus allowing the comparison of all alkali metal hydroxide structures. Raman spectroscopic investigations show the hydroxide anion to behave almost as a free ion as in the gas phase. The X-ray investigations indicate possible H atom positions.

The reaction of [{Ir(μ-Cl)(coe) 2 } 2 ] (coe=cis-cyclooctene) with triphenylphosphane (molar ratio of Ir to P=1 : 3) in dichloromethane at room temperature afforded after a short reaction time the cyclometallated complex [IrCl(H)(C 6 H 4 PPh 2 )(PPh 3 ) 2 ] (1) in almost quantitative yield. The molecular structure of the title compound 1 was determined by an X-ray diffraction study.

B-Nitrosooxypentamethylborazine, B-nitrooxypentamethylborazine and B-trinitrooxy-N-trimethylborazine have been synthesized and characterized by 1 H, 13 C, 11 B, and 14 N NMR spectroscopy, mass spectrometry, vibrational spectroscopy and elemental analysis. The 11 B NMR shifts were calculated and compared to the experimental results. The decomposition temperatures and the impact and friction sensitivities of these compounds have been determined as well.

The 5,5′-bibenzimidazolium dibromide salts 2 and 3 have been prepared by fourfold N-alkylation of 5,5′-bibenzimidazole (2: R=Pr; 3: R=Bu). The diazolium salts were treated with silver oxide, and the in situ-formed silver complexes were subsequently reacted with [AuCl(SMe 2 )] to give the dinuclear gold complexes 4 and 5. The molecular structure of complex 5 has been determined by X-ray diffraction showing linearly coordinated gold(I) centers and, most likely due to steric crowding around the metal centers, no aurophilic interactions.

Reaction of Ti(OBu) 4 or Zr(OBu) 4 with tbutyl-calix[4]arene, calix tBu (OH) 4 , led to the formation of Ti 2 (OBu) 2 [calix tBu O 3 (OH)] 2 and Zr 3 (OBu) 8 (calix tBu O 4 ), respectively. Upon in situ generation of water in the reaction with Zr(OBu) 4 , the partially hydrolyzed compound Zr 4 O(OBu) 6 (calix tBu O 4 ) 2 (BuOH) 2 was isolated.

The thallium triborate HP-TlB 3 O 5 (HP=high-pressure) was synthesized in a Walker-type multianvil apparatus under high-pressure=high-temperature conditions of 6 GPa and 1400°C. A mixture of thallium carbonate Tl 2 CO 3 and boric acid H 3 BO 3 initially heated at 850°C under ambient-pressure conditions was used as a precursor for the high-pressure experiment. Single-crystal X-ray diffraction data revealed that HP-TlB 3 O 5 is isotypic to HP-M′B 3 O 5 (M′ =K, Rb). Furthermore the B-O network is identical to the substitutional variants HP-M″B 3 O 5 [M″ =Cs 1-x (H 3 O)x (x=0.5 - 0.7), NH 4 ]. HP-TlB 3 O 5 crystallizes with eight formula units (Z =8) in the monoclinic space group C2=c (no. 15). The lattice parameters are a=996.3(2), b=884.0(2), c=913.1(2) pm, β =103:3(1)°, and V =782.5(3) Å 3 . Trigonal-planar BO 3 groups, corner-sharing BO 4 tetrahedra, and B 2 O 6 groups consisting of two edge-sharing BO 4 tetrahedra are present in the structure, forming a three-dimensional network. The thallium ions are located in channels of the boron-oxygen network being tenfold coordinated by oxygen atoms and do not show any lone pair effect at all. IR and Raman spectroscopic investigations were performed on single crystals of the compound.

Alkynyl(ferrocenyl)vinylsilanes containing up to three alkynyl units were prepared and treated with 9-borabicyclo[3.3.1]nonane (9-BBN). All reactions proceeded in the beginning by regioselective 1,2-hydroboration of the vinyl group, with boron attached to the terminal carbon. This was followed by intra-molecular 1,1-carboboration, leading to fused silacarbacycles, depending on the number of C≡C bonds. Thus, new siloles and even fused siloles became available. The solution-state structures were revealed by multinuclear NMR techniques ( 1 H, 11 B, 13 C, 29 Si NMR), complemented by calculated single-molecule structures and calculated NMR parameters at the B3LYP/6-311+G(d,p) level of theory. In one case, the solid-state structure of a bicyclic derivative was determined.

The synthesis of 2-(1-(prop-2-yn-1-yl)-1H-pyrazol-3-yl)pyridine is presented. This ligand contains both, an alkynyl function being suitable for metal-carbon bond formation with electron-rich late transition metal sites, and a pyrazolylpyridine unit, which is well-known to undergo chelation reactions similar to 2,2′-bipyridine. This strategy allows building up polynuclear complexes with broad combinations of different metal sites. Two platinum alkynyl complexes were structurally characterized, and a trinuclear Ru2Pt complex was indentified by means of NMR spectroscopy and ESI mass spectrometry.

The addition reactions of N,N′-bis(diphenylphosphanylmethyl)-2,3-dihydro-1H-perimidine (1) with [(cod) 2 Ni] and [(Ph 3 P)AuCl] yield yellow [(1)Ni(η 4 -cod)] (2) and colorless [(1)(Ph 3 P)AuCl]·3MeOH (3), respectively. In these transition metal complexes of nickel(0) and gold(I) 1 acts as a bidentate chelating ligand. Crystal structures of [(1)Ni(η 4 -cod)]·3THF (2a) and of cosolvent-free [(1)Ni(η 4 -cod)] (2) reveal a distorted tetrahedral environment of the nickel atom. The gold(I) atom in 3 exhibits a very long Au-Cl bond of 296.2(1) pm. In contrast to the nickel complexes, compound 3 shows strong agostic interactions between gold(I) and a methylene fragment.

The compound {[Cu(C 5 H 14 N 2 ) 2 ] 3 [V 15 As 6 O 42 (H 2 O)]} was synthesized under solvothermal conditions. During the reaction the V V species of NH 4 VO 3 are reduced to V IV providing the 15 reduced V IV centers in the anionic cluster. The compound crystallizes in the non-centrosymmetric orthorhombic space group P2 1 2 1 2 1 with four formula units in the cell, V =9464:8(4) Å 3 . The structure features [V 15 As 6 O 42 (H 2 O)] 6- anions which are joinded by Cu 2+ -centered complexes to form linear chains. If a long Cu-O bond is considered as weak intermolecular interaction a three-dimensional network is generated. The compound is partially soluble in water as evidenced by UV/Vis spectroscopy and mass spectra. The magnetic susceptibility of the compound is dominated by strong intra-cluster antiferromagnetic exchange interactions.

The reaction between (tht)AuCl (tht = tetrahydrothiophene) and KSCN leads to a mixture possibly consisting of gold(I) thiocyanate and [Au(tht) 2 ] + [Au(SCN) 2 ] - . This can be treated with pyridine to give the ionic derivative [Au(py) 2 ] + [Au(SCN) 2 ] - (1), for which the structures of two polymorphs were determined. Orthorhombic polymorph 1a (space group Pbcn, Z = 4) consists of infinite chains of alternating cations and anions with all gold atoms lying on a twofold axis, whereas triclinic polymorph 1b (space group P1̅, Z = 2) contains isolated tetranuclear units cation···anion···anion···cation with inversion symmetry. In both patterns the gold atoms are linked by short aurophilic contacts. Attempts to recrystallize 1b from dichloromethane-diethyl ether led to small quantities of tetrapyridinium bis(dithiocyanatogold(I)) sulfate (2), (pyH) 4 [Au(SCN) 2 ] 2 (SO 4 ), which was identified by crystal structure analysis. The cations are associated with the sulfate ions by classical hydrogen bonds; aurophilic interactions between the anions lead to dimers, which further associate to chains by Au···S contacts.

The structures of the molecules C(SiXMe 2 ) 4 (X=H, F, Cl, Br) have been determined by gas electron diffraction (GED). Ab initio calculations revealed nine potential minima for each species, with significant ranges of energies. For the H, F, Cl, and Br derivatives nine, seven, two, and two conformers were modelled, respectively, as they were quantum-chemically predicted to be present in measurable quantities. Variable-temperature 1H and 29Si solution-phase NMR studies and, where applicable, 13 C NMR, 1 H/ 29 Si NMR shift-correlation, and 1 H NMR saturation-transfer experiments are reported for C(SiXMe 2 ) 4 (X=H, Cl, Br, and also I). At low temperature in solution two conformers (one C 1 -symmetric and one C 2 -symmetric) are observed for each of C(SiXMe 2 ) 4 (X=Cl, Br, I), in agreement with the isolated molecule ab initio calculations carried out as part of this work for X=Cl, Br. C(SiHMe 2 ) 4 is present as a single C 1 -symmetric conformer in solution at the temperatures at which the NMR experiments were performed.

Treatment of a variety of alkyl- and arylsilanes, R 4-n Si(C≡C-R′)n, and -germanes, R 4-n Ge(C≡C-R′)n (1-7), with equimolar quantities of the dialkylmetal hydrides HMR″ 2 (M = Al, Ga; R″ = CMe 3 , CH 2 CHMe 2 ) yielded by reduction of a single alkynyl group a series of mixed alkenyl-alkynyl compounds R 4-n Si(C≡C-R′) n-1 {C(MR″ 2 ) =CHR′} (n = 2, 3) and R 2 Ge(C≡C-R′){C[M(CMe 3 ) 2 ]=CHR′} (8-13). Reactions with two equivalents of the hydrides afforded the dialkenyl compounds R 2 E{C[(M(CMe 3 ) 2 ]=CHR′} 2 (E = Si, Ge, 14-17), Ge(C≡C- CMe 3 ) 2 {C[Ga(CMe 3 ) 2 ]=CH-CMe 3 } 2 (18) and MeSi(C≡C-p-Tol){C[Ga(CMe 3 ) 2 ]=CH-p-Tol} 2 (19) [R = Ph, Mes, Me, C 6 F 5 ; R′ = CMe 3 , Ph). Most of the products were characterised by Xray crystallography which for the alkenyl-alkynyl derivatives revealed short intramolecular contacts between the coordinatively unsaturated metal atoms and the a-C atoms of unreacted ethynyl groups C α ≡C-R′.

A systematic investigation of the coordination behavior of P n complexes towards the main group Lewis acids Tl + and In + is presented. While the reaction of the tetrahedral P 2 complex [{CpMo(CO) 2 } 2 (μ,η 2 :η 2 -P 2 )] (A1) with Tl[TEF] ([TEF] = [Al{OC(CF 3 ) 3 } 4 ] - ) leads to the formation of the dicationic complex [Tl 2 (A1) 6 ] 2+ (1) with a central six-membered Tl 2 P 4 ring, the analogous reaction with In[TEF] leads instead to a tetranuclear [In 4 (A1) 8 ] 4+ complex (3) exhibiting a weak In I -In I interaction in the solid state. When the Cp*-analogous P 2 complex [{Cp*Mo(CO) 2 } 2 (μ,η 2 :η 2 -P 2 )] (A2) is reacted with Tl[TEF] the dinuclear complex [Tl 2 (A2) 4 ] 2+ (2) is formed, containing only four P 2 ligands but also featuring a six-membered Tl 2 P 4 ring motif. From the reactions of the cyclo-P 3 complexes [CpM'(CO) 2 (η 3 -P 3 )] (M' = Cr (B1), Mo (B2)) with In[TEF] and Tl[TEF], a series of four isostructural one-dimensional coordination polymers (4a-d) are obtained which exhibit a novel bridging coordination mode of the cyclo-P3 ligands in the solid state. Additionally, the mixed P m S n ligand complex [(Cp*Mo) 2 (μ,η 3 :η 3 -P 3 )(μ,η 2 :η 2 -PS)] (C) was reacted with Tl[TEF] to afford a novel one-dimensional coordination polymer (5), which shows an unprecedented bridging s-1,3-coordination mode of ligand C towards Tl + . The compounds were analyzed by single-crystal X-ray structure determination, elemental analysis, and mass spectrometry, as well as by multinuclear NMR and IR spectroscopy. All products are readily soluble in CH 2 Cl 2 , despite in many cases being polymeric in the solid state. Multinuclear NMR spectroscopy suggests a highly dynamic coordination behavior in solution, including fast equilibria between different monomeric species, which is also supported by DFT calculations. The one-dimensional polymers 4c and 4d reveal a triplet in the 31 P{ 1 H} MAS NMR spectrum at room temperature, which could be explained by fast rotation of the P 3 rings in the solid state.

The RSCH 2 CH 2 B(C 6 F 5 ) 2 boranes 3a (R=Ph) and 3b (R=Et) were in situ generated by HB(C 6 F 5 ) 2 hydroboration of the respective vinylthioethers. Their treatment with R 1 -C≡C- SiMe 3 acetylenes resulted in clean 1,1-carboboration to give the respective RSCH 2 CH 2 -substituted alkenylboranes 4 (3 examples). Likewise, the reagents 3 underwent 1,1-carboboration with the acetylenes Ar 2 P-C≡C-SiMe 3 to give the tetrasubstituted alkenylboranes 6, featuring a geminal pair of RSCH 2 CH 2 =B(C 6 F 5 ) 2 substituents at one carbon atom and the Me 3 Si=PAr 2 pair at the other (3 examples). The compounds 6 feature an internal B···P interaction. The conceptually related Mes 2 PCH 2 CH 2 B(C 6 F 5 ) 2 borane (2) does not undergo 1,1-carboboration with ArS-C≡C-SiMe 3 but forms the 1,2-P=B-FLP addition product 7 to the acetylene instead. Compounds 4a, 4c, 6a, and 7 were characterized by X-ray diffraction.

Three dinuclear zinc carboxylate complexes [L 1-3 Zn(μ,η 2 -O 2 CPh)] 2 (1, 2, 4) containing either the bidentate N,N′-chelating β-diketiminate ligand RNC(Me)C(H)C(Me)NR (R = 2,6-iPr 2 -C 6 H 3 , L 1 , complex 1), the tridentate O,N,N-chelating ligand OC(Me)C(H)C(Me)NCH 2 CH 2 NMe 2 (L 2 , complex 2) or the bis-N,N′-chelating bis-β-diketiminate ligand RNC(Me)C(H)C(Me)NNC(Me)- C(H)C(Me)NR (R = 2,6-iPr 2 -C 6 H 3 , L 3 , complex 4) were synthesized and characterized including single-crystal X-ray diffraction. Reaction of the neutral bis-β-diketimine (L 3 (H) 2 ) with two equivalents of ZnMe 2 leads to the expected heteroleptic dinuclear zinc complex L 3 (ZnMe) 2 3 in 93% yield. Further reaction with benzoic acid PhCO 2 H leads to complex 4. Complex 2 forms a rather strong carboxylate-bridged dimer, whereas the carboxylate groups in complexes 1 and 4 act as asymmetrical bridges between both Zn atoms, pointing to the formation of a weakly bonded dimer. The zinc atoms in 1 and 4 are tetrahedrally coordinated, whereas in 2 the coordination number is increased to five due to the coordination of the pendant donor arm. The ring opening polymerization (ROP) of rac-lactide was investigated with the zinc complexes 1-4 and diazabicycloundec-7-ene (DBU) as a co-catalyst. Complexes 2 and 3 are active polymerization catalysts, which in the presence of DBU converted 200 equiv. of rac-lactide into polylactide within 10 min at ambient temperature. The analysis of the crude polymer showed that the lactide polymerization with catalyst 2 occurs via a slightly modified activated-monomer mechanism.

Heteroleptic ate complexes of the type K[M{N(SiMe 3 ) 2 } 2 {OSi(O t Bu) 3 }] (M = Cr, Mn, Co) were synthesized by adding one equivalent of the potassium salt KOSi(O t Bu) 3 to the bis(trimethylsilyl)amide precursors [Cr{N(SiMe 3 ) 2 } 2 (thf) 2 ], [Mn{N(SiMe 3 ) 2 } 2 (thf)] and [Co{N(SiMe 3 ) 2 } 2 (thf)], respectively. Surprisingly, the reaction of CrCl 3 (thf) 3 with only two equivalents of KOSi(O t Bu) 3 yielded the homoleptic ate complex K[Cr{OSi(O t Bu) 3 } 4 ]. The compounds were characterized by elemental analysis and DRIFT spectroscopy as well as X-ray crystallography.

1,3,4,5-Tetraisopropyl-2-thioimidazoline (6b) was prepared by condensation of N,N′-diisopropylthiourea and isobutyroin. 1,3,4,5-Tetraisopropyl-2-oxoimidazoline (6a), 1,3,4,5-tetraisopropyl-2- selenoimidazoline (6c) and 1,3,4,5-tetraisopropyl-2-telluroimidazoline (6d) were obtained from 2,3- dihydro-1,3,4,5-tetraisopropylimidazol-2-ylidene and dinitrogen oxide or selenium and tellurium, respectively. The crystal structure analyses revealed the presence of the A-type rotamer for 6a while for 6c a paddlewheel-like orientation of the isopropyl substituents was found (I type). In crystals of 6b, both A- and E-type molecules are present while in solution at room temperature the I-type rotamer is detected. A dynamic 1 H and 13 C{ 1 H} NMR study of 6b in the range of 185.5 to 423.3K revealed a temperature-dependent rotation of the isopropyl substituents (ΔH‡ = 15:7(9) kcal mol -1 , ΔS‡ = -5(3) calK -1 mol -1 , ΔG‡ = 17:2(9) kcal mol -1 ) with I as the rotamer of lowest energy. This result is confirmed by MO calculations which indicate A and C being the next stable rotamers. The barrier of rotation of the isopropyl substituents about the C-N bond from I to C (B3LYP ΔH‡ =13:7 kcal mol -1 ,ΔG‡ =15:4 kcal mol -1 ) is slightly lower than that about the C-C bond from I to G.

Diamines such as (R,R)-TMCDA (1) form anellated dications with dihalomethanes, which were obtained in the presence of copper(I)halides as salts containing halocuprate anions. Using the chiral diamine (R,R)-TMCDA (1) and its meso-form cis-TMCDA (2) trichloro- and tribromocuprates with trigonal-planar geometry, and with TMEDA (3) a continuous chain of copper(I)iodid were formed. The crystal structures were discussed and compared in terms of the influence of the dication on the structural behavior of the corresponding anion. Overall we revealed an easy access to chiral or achiral dications which are based on the readily available (R,R)-TMCDA (1) and its isomer cis-TMCDA (2).

The transsilylation reaction between allyltrichlorosilane and 8-trimethylsiloxyquinoline in the molar ratio 1 : 3 yields the hexacoordinated silicon tris-chelate (oxinate) 2 Si(adho) (“oxinate” = 8- oxyquinolinate, “adho” = di-anion of 2-allyl-1,2-dihydro-8-oxyquinoline) comprising an SiO 3 N 3 skeleton. The identity of this complex was established by single-crystal X-ray diffraction analysis and 29 Si CP=MAS NMR spectroscopy of its chloroform solvate. Benzyltrichlorosilane and dibenzyldichlorosilane, comprising benzyl (Bn) as an “aromatically stabilized allyl moiety” did not undergo such rearrangement. Instead, the complexes (oxinate) 2 SiBnCl and (oxinate) 2 SiBn 2 were obtained even upon using three molar equivalents of 8-trimethylsiloxyquinoline. We determined the crystal structure of a non-disordered bis-chelate (oxinate) 2 SiBnCl with Sibound hydrocarbyl and halogen substituents (the previously published (oxinate) 2 SiMeCl was disordered with alternative Me=Cl site occupancies). (Oxinate) 2 SiBnCl exhibits surprisingly poor response of the N-Si bonds to the different trans-disposed Si-X (X=Bn, Cl) bonds. For comparison and deeper insights into the coordination chemistry of oxinato silicon complexes with halide substituents, we determined the crystal structures of (oxinate) 2 SiPhCl·CHCl 3 , (oxinate) 2 SiCl 2 , (oxinate) 2 SiF 2 ·1.5(CHCl 3 ), and (8-oxyquinaldinate) 2 SiF 2 . Furthermore, the crystal structures of BnSiCl 3 and Bn 2 SiCl 2 (and its dibromo analog) are reported. The influence of the Si-C-C-C torsion angles of the benzyl group on the 29 Si NMR shift of benzylsilanes (which is noticeably upfield with respect to analogous methyl silanes) was analyzed by quantum-chemical calculations.

The reaction of transition metal thiocyanates with 3-acetylpyridine (3-Acpy) leads to the formation of compounds of compositions M(NCS) 2 (3-Acpy) 4 (M1; M = Mn, Fe, Ni) and M(NCS) 2 (3- Acpy) 2 (H 2 O) 2 (M2; M = Mn, Fe, Ni). Thermogravimetric investigations show that in the first step some of these compounds transform into the new coordination polymers M(NCS) 2 (3-Acpy) 2 (M3 with M = Mn, Fe and Ni), that decompose into the new compounds M(NCS) 2 (3-Acpy) (M4 with M = Mn and Ni) in the second step. Unfortunately, the powder patterns of compounds M3 and M4 cannot be indexed, and there are strong indications that these compounds are contaminated with a small amount of the precursor or unknown crystalline phases. IR spectroscopic investigations indicate that in compounds M3 the metal cations are linked by μ-1,3-bridging thiocyanato anions into 1D or 2D coordination polymers that are further linked by the 3-Acpy ligands in compounds M4.

Bis-2-thienyldiethylaminophosphane (C 4 H 3 S) 2 PNEt2 (1) is introduced as a ligand for late transition metal complexes ([(H 3 C 4 S) 2 PNEt 2 ]nMXmLp), with M = Ni(II), Au(I), Cu(I), Pd(II), Ir(I), X = Cl, Br and L = NCMe, COD, (2-7). Reactions of 1 with the late transition metal salts NiCl 2 ·dme, (Me 2 S)AuCl, CuCl, PdCl 2 (PhCN) 2 , and [Ir(COD)Cl] 2 yield the complexes [{(H 3 C 4 S) 2 PNEt 2 }2 · NiCl 2 ] (2), [(H 3 C 4 S) 2 PNEt 2 · AuCl] (3) [(H 3 C 4 S) 2 PNEt2·CuCl(CH 3 CN)] 2 (4), [{(H 3 C 4 S) 2 PNEt 2 }2 · PdCl 2 ] (5), [{(H 3 C 4 S) 2 PNEt 2 }2·PdCl 2 ] 2 (6), and [(H 3 C 4 S) 2 PNEt 2· IrCl(COD)] (7). In addition, the transformation of 1 to the valuable chlorine-substituted starting material (H 3 C 4 S) 2 PCl (8) and the related conversion of 8 to the secondary phosphane (H 3 C 4 S) 2 PH (9) is reported. The complexes 2-7 are stable under inert gas conditions and were characterized by single-crystal X-ray studies, NMR spectroscopy, and elemental analysis.