Home About us Contact
|
Home About us Contact | ||
|
|
||
Title Complex (title + complex)
Selected AbstractsCarboxy Ester Hydrolysis Promoted by a Dicopper(II) Macrocyclic Polyamine Complex with Hydroxypropyl Pendant GroupsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2004Jin Huang Abstract A dinuclear CuII complex containing a hexaaza macrocyclic ligand bearing two 2-hydroxypropyl pendants, 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxypropyl)tricyclo[22.2.2.211,14]triaconta-1,11,13,24,27,29-hexaene (L), was synthesized. The title complex [Cu2(H,2L)Cl2]·6.5H2O was isolated as a blue crystal, orthorhombic, space group Fddd, with a = 16.4581(12), b = 32.248(2), c = 35.830(2) Å, V = 19017(2) Å3, Z = 16, R1 = 0.0690, and wR2 = 0.1546 [I > 2,(I)]. The protonation constants of Cu2L were determined by potentiometric titration, and it was found that the alcoholic hydroxypropyl group of the complex Cu2L exhibits low pKa values of pKa1 = 7.31, pKa2 = 7.83 at 25 °C. The hydrolysis kinetics of 4-nitrophenyl acetate (NA) promoted by the title complex have also been studied. The pH-rate profile for Cu2L gave a sigmoidal curve and showed a second-order rate constant of 0.39 ± 0.02 M,1 s,1 in 10% CH3CN/H2O(v/v), which is greater than that of the dinuclear CuII complex formed by a hexaaza macrocycle without pendants. The reason for the higher catalytic activity of the title complex is discussed. We found that the volume of nucleophile RO, can effect the hydrolysis of the carboxy ester, the nucleophilicity of RO, and the Lewis acidity of the metal macrocycle also affect the carboxy ester hydrolysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Poly[bis(,-4-benzoyl-1-isonicotinoylthiosemicarbazide-,2N:S)dichloridocadmium(II)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2010Yu-Bo Wang The asymmetric unit of the title complex, [CdCl2(C14H12N4O2S)2]n, consists of one CdII ion located on the crystallographic inversion centre, one 4-benzoyl-1-isonicotinoylthiosemicarbazide ligand and one chloride ligand. The central CdII ion adopts a distorted octahedral coordination geometry formed by two pyridyl N atoms of two ligands, two S atoms of two other ligands and two chloride ligands. The thiosemicarbazide ligands act as bridges, linking the metal ions into a two-dimensional layered structure parallel to the bc plane. Intermolecular N,H...O hydrogen bonds and C,H..., interactions exist between adjacent layers. [source] Trans influence in a mer -octahedral triiodidolanthanide: triiodidotris(tetrahydrofuran-,O)ytterbium(III)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009Thomas J. Emge The structure of the six-coordinate title complex, [YbI3(C4H8O)3], is the first mer -octahedral form of an LnI3L3 lanthanide (Ln) compound with neutral L ligands, and is closely related to that of several of the seven-coordinate LnX3L4 series of compounds, where X = Cl, Br or I and L = tetrahydrofuran (THF), isopropanol, pyridine or water. A structural trans effect can be assigned to YbI3(THF)3, in contrast to the LnX3L4 compounds, where steric and crystal packing effects are significant. The Yb,I bond lengths are 2.9543,(4) and 2.9151,(6),Å for I trans and cis to I, respectively, and the Yb,O bond lengths are 2.299,(5) and 2.251,(3),Å for O trans and cis to I, respectively. The crystal packing allows for six contact distances as weak C,H...I interactions in the range 3.10,3.24,Å. The title molecule has a crystallographic twofold axis passing through a THF O atom, the trans I atom and the Yb atom. [source] Poly[[diaqua(,3 -2,2-dimethylmalonato)cadmium(II)] tetrahydrate]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009Ming-Lin Guo In the title complex, {[Cd(C5H6O4)(H2O)2]·4H2O}n, the dimethylmalonate,cadmium metal,organic framework co-exists with an extended structure of water molecules, which resembles a sodalite-type framework. In the asymmetric unit, there are five independent solvent water molecules, two of which are in special positions. The Cd atoms are eight-coordinated in a distorted square-antiprismatic geometry by six O atoms of three different dimethylmalonate groups and by two water molecules, and form a two-dimensional honeycomb layer parallel to the bc plane. Two such layers sandwich the hydrogen-bonded water layer, which has a sodalite-type structure with truncated sodalite units composed of coordinated and solvent water molecules. This work is the first example of a dimethylmalonate cadmium complex containing truncated sodalite-type water clusters. [source] Trinitratobis{N,-[1-(2-pyridyl)ethylidene]isonicotinohydrazide}cerium(III): a three-dimensional cerium,organic supramolecular structureACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009Ying-Ying Zhang The CeIII ion in the title complex, [Ce(NO3)3(C13H12N4O)2], is 12-coordinated by six chelating nitrate O atoms and six donors (2 O and 4 N atoms) of two N,-[1-(2-pyridyl)ethylidene]isonicotinohydrazide ligands, exhibiting a bicapped pentagonal-antiprism-type coordination geometry. The title complex possesses C2 point symmetry and is located on a twofold crystallographic axis. Each molecule is linked with four surrounding molecules by four N,H...N hydrogen bonds, resulting in an extended two-dimensional layer parallel to the ab plane, while ,,, interactions between pyridine rings from neighboring complex molecules connect the two-dimensional layers into a three-dimensional cerium,organic supramolecular structure. [source] Poly[[tetraaquatris(,3 -2,2-dimethylmalonato)dilanthanum(III)] monohydrate]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Ming-Lin Guo In the title complex, {[La2(C5H6O4)3(H2O)4]·H2O}n, the La atoms are connected by bridging O atoms from carboxylate groups to build, through centres of inversion, two-dimensional layers parallel to the ac plane containing decanuclear 20-membered rings. The coordinated water molecules are involved in intralayer hydrogen-bond interactions. Adjacent layers are linked via hydrogen bonding to the solvent water molecules. This work represents the first example of a new substituted malonate,lanthanide complex. [source] Dimeric (isoquinoline)(N -salicylidene- d,l -glutamato)copper(II) ethanol solvateACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Vratislav Langer The title racemic complex, bis[,- N -(2-oxidobenzylidene)- d,l -glutamato(2,)]bis[(isoquinoline)copper(II)] ethanol disolvate, [Cu2(C12H11NO5)2(C9H7N)2]·2C2H6O, adopts a square-pyramidal CuII coordination mode with a tridentate N -salicylideneglutamato Schiff base dianion and an isoquinoline ligand bound in the basal plane. The apex of the pyramid is occupied by a phenolic O atom from the adjacent chelate molecule at an apical distance of 2.487,(3),Å, building a dimer located on the crystallographic inversion center. The Cu...Cu spacing within the dimers is 3.3264,(12),Å. The ethanol solvent molecules are hydrogen bonded to the dimeric complex molecules, forming infinite chains in the a direction. The biological activity of the title complex has been studied. [source] catena -Poly[[[aqua[3-(2-pyridylsulfanyl)propionato N -oxide-,O1]copper(II)]-,-[3-(2-pyridylsulfanyl)propionato N -oxide-,3O3:O1,O1,] dihydrate]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2008Murugan Indrani In the title complex, {[Cu(C8H8NO3S)2(H2O)]·2H2O}n, the CuII cation has a distorted square-pyramidal coordination environment consisting of five O atoms, one from a water molecule, one from an N,O group and the other three from the carboxylate groups of two 3-(2-pyridylsulfanyl)propionate N -oxide anions. The aqua[3-(2-pyridylsulfanyl)propionato N -oxide]copper(II) moieties are bridged by 3-(2-pyridylsulfanyl)propionate N -oxide anions to form an infinite three-dimensional coordination polymer with a zigzag chain structure. The crystal structure is stabilized by hydrogen bonds. [source] Tetraaquabis(2-methoxybenzaldehyde isonicotinoylhydrazone)cadmium(II) dinitrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2007Zhongwu Fu The CdII centre in the title complex, [Cd(C14H13N3O2)2(H2O)4](NO3)2, occupies a crystallographic inversion centre and is coordinated by two donor N atoms from two 2-methoxybenzldehyde isonicotinoylhydrazone ligands and by four O atoms from four coordinated water molecules, giving a slightly distorted octahedral geometry. There is an extended three-dimensional network structure resulting from O,H...O hydrogen bonds between coordinated water and nitrate anions, and between coordinated water and carbonyl O atoms, and from N,H...O hydrogen bonds between NH groups and nitrate O atoms. [source] Tetraaquabis(5-carboxy-2-nitrobenzoato-,O)manganese(II) dihydrate: a metal,water chain complex containing cyclic water tetramersACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2007Li-Qin Xiong In the title complex, [Mn(C8H4NO6)2(H2O)4]·2H2O, cyclic water tetramers forming one-dimensional metal,water chains have been observed. The water clusters are trapped by the co-operative association of coordination interactions and hydrogen bonds. The MnII ion resides on a center of symmetry and is in an octahedral coordination environment comprising two O atoms from two 5-carboxy-2-nitrobenzoate ligands and four O atoms from water molecules. [source] A novel dimeric zinc(II) complex: bis[,-1,2-bis(1H -1,2,4-triazol-1-yl)ethane-,2N4:N4,]bis[diisothiocyanatozinc(II)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2007Yu-Mei Zhang The coordination geometry of the ZnII atom in the title complex, [Zn2(NCS)4(C6H8N6)2], is that of a distorted tetrahedron, in which the ZnII atom is coordinated by four N atoms from the triazole rings of two symmetry-related 1,2-bis(1,2,4-triazol-1-yl)ethane ligands and two thiocyanate ligands. Two ZnII atoms are bridged by two organic ligands to form a dimer. The dimer lies about an inversion center. [source] Poly[[di-,3 -acetato-di-,2 -aqua-diaqua-di-,3 -hydroxo-tricopper(II)] naphthalene-1,5-disulfonate]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2006Li-Li Kong The crystal structure of the title complex, {[Cu3(C2H3O2)2(OH)2(H2O)4](C10H6O6S2)}n, is built of infinite polymeric cationic {[Cu3(C2H3O2)2(H2O)4(OH)2]2+}n chains stretching along the a axis, with naphthalene-1,5-disulfonate (1,5-nds) anions in between. One independent CuII cation and the 1,5-nds anion occupy special positions on crystallographic inversion centres. Each CuII cation has an octahedral coordination environment formed by two carboxyl O atoms, two hydroxo O atoms and two water molecules. The carboxylate and hydroxo groups perform a bridging function, linking adjacent Cu atoms in the chain, with a shortest Cu,Cu distance of 2.990,(3),Å. The chains are further linked into a three-dimensional supramolecular framework via hydrogen-bonding interactions involving the sulfonate groups of the 1,5-nds dianions. [source] Crystallographic report: A synthetic precursor for hetero-binuclear metal complexes, [Ru(bpy)(dppy)2(CO)2](PF6)2 (bpy = 2,2,-bipyridine, dppy = 2-(diphenylphosphino)pyridine)APPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2004Dai Ooyama Abstract In the title complex, [Ru(bpy)(dppy)2(CO)2](PF6)2 (bpy = 2,2,-bipyridine, dppy = 2-(diphenylphosphino)pyridine), the ruthenium atom exhibits a slightly distorted octahedral coordination with the carbonyl ligands in cis positions. In addition, two dppy ligands coordinate to the ruthenium center through the phosphorus atoms in mutually trans positions and two pyridyl nitrogen atoms of the dppy direct toward two carbonyl ligands. Copyright © 2004 John Wiley & Sons, Ltd. [source] ,-Biphenyl-2,2,-dithiolato-,2S:S,-bis[(triphenylphosphine-,P)gold(I)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2004Scott A. Larkin The reaction of ClAuPPh3 and 1,1,-biphenyl-2,2,-dithiol in the presence of trimethylbenzylammonium chloride and K2CO3 in a tetrahydrofuran/methanol solution gives the title complex, [Au2(C12H8S2)(C18H15P)2]. The molecule contains P,Au,S units which `cross' with torsion angles of ,90° [P,Au,Au,P = 86.23,(5)° and S,Au,Au,S = 95.62,(5)°]. The intra- and intermolecular Au,Au distances [3.9064,(3) and 6.3797,(5),Å, respectively] are outside the range for typical Au,Au interactions. However, the Au atoms appear to be drawn together, leading to a significant bending of the P,Au,S angles [170.24,(5) and 169.52,(5)°]. [source] catena -Poly[bis[(2,2-bipyridine-,2N,N,)copper(II)]-,4 -1,2,4,5-benzenetetracarboxylato-,4O1:O2:O3:O4]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2004Hong-Ping Xiao In the title complex, [Cu2(C10H2O8)(C10H8N2)2]n, the CuII cation has a four-coordinated environment, completed by two carboxyl O atoms belonging to two 1,2,4,5-benzenetetracarboxylate anions (TCB4,) and two N atoms from one 2,2,-bipyridine (2,2,-bipy) ligand, forming a distorted square-planar geometry. The [Cu(2,2,-bipy)]2+ moieties are bridged by TCB4, anions, which lie about inversion centres, forming an infinite one-dimensional coordination polymer with a double-chain structure along the a axis. A two-dimensional network structure is formed via a face-to-face ,,, interaction between the 2,2,-bipy rings belonging to two adjacent double chains, at a distance of approximately 3.56,Å. [source] Arene,perfluoroarene interactions in crystal engineering.ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2001In the title complex, C6F6·C14H12, nearly parallel molecules of trans -stilbene and librationally disordered hexafluorobenzene form a mixed stack, with each molecule lying on an independent inversion centre. Adjacent stacks pack together in a herring-bone manner. [source] catena -Poly[[trans -dichlorocopper(II)]-,-1,4,7,10,13,16-hexathiacyclooctadecane- S1:S10]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2001Alexander J. Blake In the title complex, [CuCl2(C12H24S6)]n, the CuCl2 unit and the ligand lie on and about inversion centres, respectively. The coordination geometry at CuII is a tetragonally elongated octahedron with the equatorial positions occupied by two chlorides, Cu,Cl 2.2786,(12),Å, and two S donors, Cu,S 2.3710,(13),Å. The apical positions of the octahedron are defined by two S donors at distances of 2.8261,(14),Å from the metal. The macrocyclic ligand adopts a very puckered and distorted conformation. Eight of the 18 torsion angles are less than 90° and all S-donors are oriented exo to the ring. [source] Tetraaqua(5-fluorouracil-1-acetato- O)copper(II) tetrahydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2000Jian Huang In the title complex, [Cu(C6H4FN2O4)2(H2O)4]·4H2O, the Cu atom is located in the centre of a distorted octahedral geometry. The coordination atoms are six O atoms provided by two carboxylate groups [coordinated in a monodentate mode, with Cu,O = 1.9551,(10),Å] and four water molecules [Cu,O = 1.9241,(13) and 2.5771,(14),Å]. In addition, one intramolecular hydrogen bond and ten intermolecular hydrogen bonds make up a three-dimensional network. [source] cis,cis,cis -(Acetato- O,O,)bis[1,2-bis(diphenylphosphino)ethane- P,P,]ruthenium(II) hexafluorophosphate dimethanol solvateACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2000Nigel T. Lucas In the cation of the title complex, cis,cis,cis -[Ru(,2 -O2CMe)(dppe)2]PF6·2MeOH [dppe is 1,2-bis(diphenylphosphino)ethane, C26H24P2], the Ru atom is in a pseudo-octahedral coordination environment with two chelating dppe ligands and one chelating acetate ligand. Intra-phosphine and intra-acetate bond lengths and angles are unexceptional. Deviations from idealized octahedral coordination angles at ruthenium [O,Ru,O 59.43,(8)° and P,Ru,P 103.19,(2)°] presumably derive from constraints imposed by the chelate rings. The Ru,P distances for the mutually trans P-donor atoms [2.3785,(6),Å] are significantly longer than those for the Ru,P linkages trans to the acetate ligand [2.3074,(6),Å]. The Ru1, C1 and C2 atoms lie on a twofold axis, and atom P3 of the anion lies on an inversion centre. [source] Manganese mercury thiocyanate (MMTC) glycol monomethyl etherACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2000Dong Xu In the title complex, [MnHg(NCS)4(C3H8O2)]n, each Hg atom is tetrahedrally coordinated with four S atoms of the SCN, ions, and each Mn atom is octahedrally coordinated with four N atoms of the SCN, ions, one hydroxyl O atom and one ethereal O atom of the glycol monomethyl ether molecule. Each pair of Hg and Mn atoms is bridged by one SCN, ion. A 24-membered Mn3Hg3(SCN)6 ring is formed as the strucrural unit, with the six metal atoms in a chair-form hexagonal arrangement. The units are condensed and linked three-dimensionally in the crystal resulting in a diamond-like structure. [source] The cyclic vanadylacetate (C24H20P)[V4O8(C2H3O2)4(NO3)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2000Dirk Wulff-Molder In the title complex, tetraphenylphosphonium ,4 -nitrato-,4O - cyclo -tetrakis(,-acetato- O:O,)tetra-,-oxo-tetrakis[oxovana-dium(V)], the anion lies about a twofold axis and consists of the cyclic [V4O8] unit coordinated by four acetato ligands with interatomic V,V distances of 3.269,(1) and 3.273,(1),Å. The double-bonded O atom [N=O 1.102,(6) and N,O 1.268,(4),Å] of the nitrato ligand links the four V atoms with V,O bond distances of 2.613,(2) and 2.813,(2),Å. The negative charge of the complex is balanced by tetraphenylphosphonium cations occupying the Na positions in the NaCl-type ionic packing of the structure. [source] Thermochemical Properties and Decomposition Kinetics of Ammonium Magnesium Phosphate MonohydrateCHINESE JOURNAL OF CHEMISTRY, Issue 1 2007Jian Wu Abstract Ammonium magnesium phosphate monohydrate NH4MgPO4·H2O was prepared via solid state reaction at room temperature and characterized by XRD, FT-IR and SEM. Thermochemical study was performed by an isoperibol solution calorimeter, non-isothermal measurement was used in a multivariate non-linear regression analysis to determine the kinetic reaction parameters. The results show that the molar enthalpy of reaction above is (28.795±0.182) kJ/mol (298.15 K), and the standard molar enthalpy of formation of the title complex is (,2185.43±13.80) kJ/mol (298.15 K). Kinetics analysis shows that the second decomposition of NH4MgPO4·H2O acts as a double-step reaction:an nth-order reaction (Fn) with n=4.28, E1=147.35 kJ/mol, A1=3.63×1013 s,1 is followed by a second-order reaction (F2) with E2=212.71 kJ/mol, A2=1.82×1018 s,1. [source] Crystal structure, thermal analysis and theoretical calculation of a one-dimensional chain complex [zn(dafo)2(H2O)2](NO3)2CHINESE JOURNAL OF CHEMISTRY, Issue 8 2004Rong-Lan Zhang Abstract A novel one-dimensional chain complex [Zn(dafo)2(H2O)2](NO3)2 was obtained when we tried synthesizing a mixed ligand supramolecular compound of Zinc(II) with dafo and o -phthalic acid. Its structure was determined by single-crystal X-ray diffraction analysis. The crystal belongs to triclinic system, P -1 space group. The crystallographic data: a=0.6989(4) nm, b=0.8281(5) nm, c=1.0231(5) nm, ,=94.934(5)°, ,=91.366(7)°, ,=99.820(7)°, V=0.5809(5) nm3, Z= 1, F(000)=300, Mr=589.78, Dc=1.686 g/cm3, ,(Mo K,)=1.130 mm,1, R1=0.0521, wR2=0.1096. The analysis of the crystal structure indicates that the compound has a one-dimensional chain structure which is formed by hydrogen bonds. The constitutes of the title complex were proved by elemental analysis, IR spectra and thermal analysis. On the basis of the experimentation, the complex was calculated by DFT-B3LW/LANL2DZ in Gaussian-98w also. [source] Synthesis, Crystal Structure of Cis -dioxo-catecholatotungsten(VI) Complex and Its NMR Studies on the Interaction with ATPCHINESE JOURNAL OF CHEMISTRY, Issue 6 2003Lu Xiao-Ming Abstract Cis -dioxo-catecholatotungsten(VI) complex anion [W(VI)O2 -(OC6H2O)]2- was obtained with discrete protonated ethylene-diamine (NH2CH2CH2NH3)+ cations by the reaction of tetra-butyl ammonium decatungstate with catechol in the mixed solvent of CH3OH, CH3CN and ethylenediamine, and compared with its molybdenum analogue [Mo(v)O2(OC6H4O)2]3- by crystal structure, UV, EPR. The results of the UV and EPR spectra show that tungsten is less redox active than molybdenum since the molybdenum is reduced from Mo(VI) to Mo(V) but tungsten stays in the original highest oxidized state Mo (VI) when they are crystallized from the solution above. It is worthy to note that [W(VI)O2(OC6H4O2)]2- shows the same coordination structure as its molybdenum analogue in which the metal center exhibits distorted octahedral coordination geometry with two cis -dioxocatecholate ligands and might have the related coordination structure feature with the cofactor of flavoenzyme because [Mo(v)O2(OC6H4O)2]3- presented essentially the same EPR spectra as flavoenzyme. The NMR studies on the interaction of the title complex with ATP reveal that the reduction of W(VI) to W(V) occurs when the title complex is dissolved in D2O and the W (V) is oxidized again when ATP solution is mixed with original solution and the hydrolysis of the catechola-to ligand take places at mean time being monitored by 1H NMR and 13C NMR spectra. [source] Transition-Metal (MnII and CoII) Complexes with the Heteropolymolybdate Fragment [AsVMo9O33]7,: Crystal Structures, Electrochemical and Magnetic PropertiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2007Yanyan Yang Abstract Two novel heteropolymolybdates, [(CH3)4N]8n[M(H2O)5]2n(H3O)2n[{M(H2O)5}2(MAsVMo9O33)2]n[M(H2O)4(MAsVMo9O33)2]n·20nH2O (M = Mn2+, 1; M = Co2+, 2), constructed from the new fragment (AsVMo9O33)7, and a transition metal have been synthesized in aqueous solution and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, and single-crystal X-ray diffraction. Structurally the title complexes resemble a sandwich-type complex because they involve the coordination of two transition metals to two [AsVMo9O33]7, fragments, which derive from the well-known B -, - Keggin structure. Compounds 1 and 2 exhibit a one-dimensional chain-like framework [M(H2O)4(MAsVMo9O33)2]8n, with isolated {[M(H2O)5]2(MAsVMo9O33)2}6, units residing among the chains. The magnetic properties of the two complexes were investigated to indicate typical antiferromagnetic interactions through the MnII,O,MnII bridge unit for complex 1 and the CoII,O,CoII bridge unit for complex 2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Structural correlations for 1H, 13C and 15N NMR coordination shifts in Au(III), Pd(II) and Pt(II) chloride complexes with lutidines and collidineMAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2010Leszek Pazderski Abstract 1H, 13C and 15N NMR studies of gold(III), palladium(II) and platinum(II) chloride complexes with dimethylpyridines (lutidines: 2,3-lutidine, 2,3lut; 2,4-lutidine, 2,4lut; 3,5-lutidine, 3,5lut; 2,6-lutidine, 2,6lut) and 2,4,6-trimethylpyridine (2,4,6-collidine, 2,4,6col) having general formulae [AuLCl3], trans -[PdL2Cl2] and trans -/cis- [PtL2Cl2] were performed and the respective chemical shifts (,1H, ,13C, ,15N) reported. The deshielding of protons and carbons, as well as the shielding of nitrogens was observed. The 1H, 13C and 15N NMR coordination shifts (,1Hcoord, ,13Ccoord, ,15Ncoord; ,coord = ,complex , ,ligand) were discussed in relation to some structural features of the title complexes, such as the type of the central atom [Au(III), Pd(II), Pt(II)], geometry (trans - or cis -), metal-nitrogen bond lengths and the position of both methyl groups in the pyridine ring system. Copyright © 2010 John Wiley & Sons, Ltd. [source] Bond catastrophes in rhodium complexes: experimental charge-density studies of [Rh(C7H8)(PtBu3)Cl] and [Rh(C7H8)(PCy3)Cl]ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2010Hazel A. Sparkes Rhodium complexes have potential uses in both catalysis and promoting the cleavage of C,C bonds. In order to further our understanding of these species and their potential applications, it is vital to obtain insight into the bonding within the species, particularly the Rh,C interactions, and to this end experimental charge-density studies have been undertaken on the title complexes. High-resolution single-crystal datasets to sin,,/, = 1.06,Å,1 were obtained at 100,K and analysed using Bader's `Atoms in Molecules' (AIM) approach. The results of the studies have provided unique insights into the bonding involving rhodium and highlight the importance of undertaking such investigations for transition metal compounds. [source] Two novel silver(I) coordination polymers: poly[(,2 -2-aminopyrimidine-,2N1:N3)bis(,3 -thiocyanato-,3S:S:S)disilver(I)] and poly[(2-amino-4,6-dimethylpyrimidine-,N)(,3 -thiocyanato-,3N:S:S)silver(I)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2009Geng-Geng Luo 2-Aminopyrimidine (L1) and 2-amino-4,6-dimethylpyrimidine (L2) have been used to create the two novel title complexes, [Ag2(NCS)2(C4H5N3)]n, (I), and [Ag(NCS)(C6H9N3)]n, (II). The structures of complexes (I) and (II) are mainly directed by the steric properties of the ligands. In (I), the L1 ligand is bisected by a twofold rotation axis running through the amine N atom and opposite C atoms of the pyrimidine ring. The thiocyanate anion adopts the rare ,3 -,3S coordination mode to link three tetrahedrally coordinated AgI ions into a two-dimensional honeycomb-like 63 net. The L1 ligands further extend the two-dimensional sheet to form a three-dimensional framework by bridging AgI ions in adjacent layers. In (II), with three formula units in the asymmetric unit, the L2 ligand bonds to a single AgI ion in a monodentate fashion, while the thiocyanate anions adopt a ,3 -,1N,,2S coordination mode to link the AgL2 subunits to form two-dimensional sheets. These layers are linked by N,H...N hydrogen bonds between the noncoordinated amino H atoms and both thiocyanate and pyrimidine N atoms. [source] Synthesis, characterization and application of benzyl-substituted cyclopentadienyl lanthanide complexes as catalyst precursors for the syndiotactic polymerization of methyl methacrylateCHINESE JOURNAL OF CHEMISTRY, Issue 6 2004Yan-Long Qian Abstract Benzyl-substituted cyclopentadienyl lanthanide complexes were synthesized and characterized by elemental analysis, MS and IR spectroscopy. The analytical data point out the formation of monomeric. unsolvated complexes. In conjunction with AI(Et)3 as co-catalyst. the title complexes are efficient catalysts for the syndiotactic polymerization of methyl methacrylate. For the complex (C6H5CH2C5H4)2YCl, under the optimum polymerization conditions (60 °C, n(MMA) : n(catalyst) : n(co-catalyst)=1000 : 1 : 10), a predominantly syndiotactic (rr=66%) polymer of high molecular weight (Mn= 105000) was obtained. [source] | ||||||||||