Crystal structure of bis-(N-tert-butyl-benzamidinium) hexa-chlorido-zirconate(IV) di-chloro-methane disolvate.

In the Zr(IV) complex anion of the title complex salt, [(C4H9)HNC(C6H5)NH2]2[ZrCl6]·2CH2Cl2, the Zr(IV) cation, located on an inversion centre, is coordinated by six Cl(-) anions in a distorted octa-hedral geometry with Zr-Cl distances in the range 2.433 (2)-2.4687 (19) Å; in the amidinium cation, the dihedral angle between the aromatic ring and [NCN] plane is 43.3 (4)°. In the crystal, the amidinium cations and [ZrCl6](2-) anions are linked by N-H⋯Cl hydrogen bonds, forming a two-dimensional network extending along the b axis; two di-chloro-methane solvent mol-ecules are linked by a pair of weak C-H⋯Cl hydrogen bonds, forming a centrosymmetric [CHCl]2 six-membered ring.

Coordination reactions of 2-pyridinecarboxaldehyde-phenylhydrazonatolithium with selected transition metal (Zn, Sn, Fe, Co, Ni and Zr) chlorides and its coupling reaction with dichloromethane.

The reactions of 2-pyridinecarboxaldehyde-phenylhydrazonatolithium C5H4Npy-CH[double bond, length as m-dash]Ni-NaLi(Ph) (abbreviated as Li) with a 1/2 equivalent of anhydrous metal (Zn, Sn, Fe and Co) chlorides or NiCl2(DME) (DME = 1, 2-dimethoxyethane) produced the corresponding mononuclear metal(ii) complexes ( and ), in which each ligand acts as a bidentate ligand and the coordination geometries around the metals are shown to be tetrahedral within the complexes , , and , respectively, and a tetragonal pyramid in the complex . The reaction of Li successively with sodium tert-butoxide and anhydrous ZrCl4 afforded the unanticipated bizirconium complex , in which each monoanionic ligand behaves as a tridentate bridge. Whereas treatment of Li with NiCl2 and then CH2Cl2 led to an interesting methylene-bridged bis(2-pyridyl-phenylhydrazone) compound in moderate yield; a comparative experiment showed that when the Li reacted with CH2Cl2, the coupling compound was also obtained but in very low yield. A plausible mechanism of compound formation was also proposed and supported by the density functional theory (DFT) calculations. All the synthesized compounds were characterized by single-crystal X-ray diffraction.

Crystal structure of N'-(2,6-di-methyl-phen-yl)benzene-carboximidamide tetra-hydro-furan monosolvate.

The asymmetric unit of the title compound, C15H16N2·C4H8O, contains two amidine mol-ecules (A and B) with slightly different conformations and two tetra-hydro-furan (THF) solvent mol-ecules. In the amidine mol-ecules, the di-methyl-phenyl ring and the NH2 group lie to the same side of the N=C bond and the dihedral angles between the aromatic rings are 54.25 (7) (mol-ecule A) and 58.88 (6) ° (mol-ecule B). In the crystal, N-H⋯N hydrogen bonds link the amidine mol-ecules into [100] C(4) chains of alternating A and B mol-ecules. Both amidine mol-ecules form an N-H⋯O hydrogen bond to an adjacent THF solvent mol-ecule.

N-Cyclo-hexyl-3-methyl-benzamidine.

The title amidine compound, C14H20N2, prepared by a one-pot reaction, is asymmetric as only one N atom has an alkyl substituent. The terminal cyclo-hexyl group connected to the amino N atom is located on the other side of the N-C-N skeleton to the 4-methylbenzene ring and has a chair conformation. The dihedral angle between the phenyl ring and the NCN plane is 47.87 (12)°. In the crystal, mol-ecules are linked via N-H⋯N hydrogen bonds, forming chains propagating along the a-axis direction.

Tetra-chlorido-[N (2),N (2')-(di-methyl-silanedi-yl)bis-(N-tert-butyl-3-methyl-benzimid-amid-ato)-κ(2) N (2),N (2')]hafnium(IV).

The symmetric title mol-ecule, [Hf(C26H40N4Si)Cl4], lies about a twofold rotation axis. The Hf(IV) and Si atoms lie on the rotation axis with all other atoms being in general positions. The Hf(IV) atom is six-coordinated by two N atoms from the N (2),N (2')-(di-methyl-silanedi-yl)bis-(N-tert-butyl-3-methyl-benz-imid-amidate) ligand and four Cl(-) ions in a slightly distorted octa-hedral geometry. The two amidinate moieties are connected through the central Si atom with Si-N bond length of 1.762 (3) Å, generating the characteristic N-C-N-Si-N-C-N skeleton of a silyl-linked ansa-bis-(amidine) species.

Metal (Mg, Fe, Co, Zr and Ti) complexes derived from aminosilyl substituted aminopyridinato ligand: synthesis, structures and ethylene polymerization behaviors of the group 4 complexes.

Lithium N-[(N,N-dimethylamino)dimethylsilyl]-2-pyridylamidate (2) was prepared from the reaction of new compound N-[(N,N-dimethylamino)dimethylsilyl]-2-pyridylamine (1) and LiBu(n). Treatment of the lithium salt (2) with an equal equivalent of MgBr(2)(THF)(2), FeCl(2) and CoCl(2) afforded the corresponding dinuclear complexes , , and , in which metal atoms possess similar trigonal bipyramidal geometries and each ligand functions as a bimetallic bridging binding aminopyridinato moiety with N-donation from the dimethylamino group. While the stoichiometric reaction of with ZrCl(4) gave the mononuclear zirconium complex (6); the seven coordinated zirconium atom adopts a distorted pentagonal bipyramid geometry and the ligand acts as monoanionic η(2)-aminopyridinato moiety with the pendant arm coordinated via N(CH(3))(2). The reaction of with one equivalent of TiCl(4)(THF)(2) produced the interesting dinuclear titanium complex (7) owing to the elimination of a (N,N-dimethylamino)dimethylsilyl group from the original ligand, and the two titanium centers present different coordination geometries. The molecular structures of the crystalline metal complexes have been confirmed by X-ray single crystal diffraction analysis. Upon activation with methylaluminoxane (MAO), both complexes and exhibited moderate catalytic activities toward ethylene polymerization and produced high molecular weight polyethylenes with broad molecular weight distributions.

meso-Bis{η(5)-1-[1-(dimethylamino)ethenyl]-3-(trimethylsilyl)cyclopentadienyl}iron(II) and the cobalt(II) analogue.

The two title crystalline compounds, viz. meso-bis{η(5)-1-[1-(dimethylamino)ethenyl]-3-(trimethylsilyl)cyclopentadienyl}iron(II), [Fe(C(12)H(20)NSi)(2)], (II), and meso-bis{η(5)-1-[1-(dimethylamino)ethenyl]-3-(trimethylsilyl)cyclopentadienyl}cobalt(II), [Co(C(12)H(20)NSi)(2)], (III), were obtained by the reaction of lithium 1-[1-(dimethylamino)ethenyl]-3-(trimethylsilyl)cyclopentadienide with FeCl(2) and CoCl(2), respectively. For (II), the trimethylsilyl- and dimethylaminoethenyl-substituted cyclopentadienyl (Cp) rings present a nearly eclipsed conformation, and the two pairs of trimethylsilyl and dimethylaminoethenyl substituents on the Cp rings are arranged in an interlocked fashion. In the case of (III), the same substituted Cp rings are perfectly staggered leading to a crystallographically centrosymmetric molecular structure, and the two trimethylsilyl and two dimethylaminoethenyl substituents are oriented in opposite directions, respectively, with the trimethylsilyl group of one Cp ring and the dimethylaminoethenyl group of the other Cp ring arranged more closely than in (II).

Chlorido{N-[(diethyl-amino)-dimethyl-sil-yl]anilido-κN}(N,N,N',N'-tetra-methyl-ethane-1,2-diamine-κN,N')cobalt(II).

In the title cobalt(II) compound, [Co(C(12)H(21)N(2)Si)Cl(C(6)H(16)N(2))], the ethane-1,2-diamine donor mol-ecule coordin-ates the metal atom in an N,N'-chelating mode, with Co-N distances of 2.136 (2) and 2.140 (3) Å. An anilide ligand connects to the Co(II) atom with a σ-bond, the Co-N(anilide) distance being 1.931 (2) Å. The four-coordinate Co(II) atom demonstrates a slightly distorted tetra-hedral geometry.

Mononuclear titanium compounds based on the silyl-linked bis(amidinate) ligand: synthesis, characterization and ethylene polymerization.

The mononuclear silyl-linked bis(amidinate) titanium compound 2 was prepared by salt metathesis of 1 and TiCl(4)(thf)(2). Alkylation of 2 with methyllithium gave analogue 3. Both 2 and 3 exhibited a configuration similar to ansa-metallocene and showed good activity towards ethylene polymerization after activation with MAO.

A bulky silyl shift-directed synthesis of a silyl-linked amidinate-amidine and its Zr(IV) complex.

A novel silyl-linked amidinate-amidine monoanionic ligand 3 was synthesized by double additions of PhCN starting from silyl-linked bis(amino) monoanion 2, which underwent an intramolecular Li/H metathesis and double silyl shift. The related Zr(IV) complex 4 was prepared and confirmed by X-ray diffraction revealing a structural rearrangement from its precursor. The mechanisms for the reaction processes have been proposed. Each of compounds 2, 3 and 4 was characterized by NMR spectroscopy, elemental analysis and X-ray diffraction. Complex 4 exhibited moderate activity for ethylene polymerization in the presence of methylalumoxane (MAO).

Ammonium benzene-phospho-nate.

In the crystal structure of the title salt, NH(4) (+).[(C(6)H(5))P(O)(2)(OH)](-) or NH(4) (+)·C(6)H(6)O(3)P(-), the N and O atoms inter-act via hydrogen bonds to generate a layer motif. The phenyl rings are stacked above and below this layer, sandwiching the hydrogen-bonded layer.

A convenient route to silyl linked bis(amidinate) ligands and synthesis of group(I) metal derivatives.

A novel type of linked bis(amidinate) ligands (D) were developed successfully. Their lithium derivatives 1-4 were synthesized by treating the silyl-bridged diamines I-IV with two equivalents of LiBu(n) and PhCN in sequence, which underwent a silyl-bridge migration process. In addition, the linked bis(amidinate) configuration proved to be the thermodynamically stable form rather than the mono(amidinate) type by contrasting reaction of I with one equivalent of LiBu(n) and PhCN in sequence.

Intramolecular NMe2H Elimination and Fulvene Coupling Leading to Novel Allyl-Bridged Zirconocene and Hafnocene Complexes.

Deprotonation of the aminofulvene 1 with LiCH(SiMe3)2 provides 2, which reacts with MCl4 (M=Zr or Hf) by intramolecular NMe2H elimination and coupling of the fulvene moieties to form complex 3 or 4. This reaction is a useful synthetic pathway to allyl-bridged ansa-metallocenes, especially those with a conjugated 14 π electron system. R'=dimethylamino.