Trichlorido(1,3-dimethyl-2,3-di-hydro-1H-imidazol-2-yl-idene-κC (2))aluminium(III).

The title compound, [Al(C5H8N2)Cl3], was prepared by a thermolytic decomposition under high-vacuum conditions and presents a formal adduct of an Arduengo carbene, 1,3-dimethyl-1H-imidazol-2-yl-idene, and aluminium trichloride. The Al atom adopts a pseudo-tetra-hedral CCl3 coordination environment. All N and C atoms, the Al atom, one of the Cl atoms, and all aromatic H atoms of the mol-ecule lie on a mirror plane. As a result of the mirror symmetry of the mol-ecule, the H atoms of all methyl groups are disordered between symmetry-equivalent positions.

Bis(1,3-dimethyl-1H-imidazolium) hexa-fluoro-silicate methanol 0.33-solvate.

The title compound, 6C5H9N2 (+)·3SiF6 (2-)·CH3OH, (I), was prepared by recrystallization of the crude salt from methanol along with solvent-free 2C5H9N2 (+)·SiF6 (2-) (II). Crystals of these solvatomorphs can be separated manually. The solvate (I) crystallizes in a rare hexa-gonal space group P6/mcc. Its asymmetric unit comprises one half of an imidazolium cation bis-ected by the crystallographic m-plane, one-sixth and one-twelfth of two crystallographically independent SiF6 (2-) dianions (Si atoms are located on the 3.2 and 6/m inversion centres), and one-twelfth of a methanol mol-ecule (C atoms are situated on the 622 inversion centres, other atoms are disordered between general positions). In (I), all F atoms of 3.2-located SiF6 (2-) dianions participate in the formation of symmetry-equivalent contacts to the H atoms of imidazolium fragments, thus forming rod-type ensembles positioned on the -6 axes. These 'pillar' rods are, in turn, F⋯H inter-linked through SiF6 (2-) dianions disordered around the 6/m centres. The twelvefold disordered methanol mol-ecules are appended to this array by O-H⋯F hydrogen bonds to the 6/m located SiF6 (2-) dianions. In terms of graph-set notation, the first and second level networks in (I) are N 1 = C 2 (2)(7)[3R 4 (4)(14)]D 2 (2)(4) and N 2 = D 2 (2)(5) (C-H⋯O hydrogen bonds are not considered). After locating all symmetrically independent atoms in the cation and anions, there remained a strong (> 3 e Å(-3)) residual electron density peak located at the 622 inversion centre. Treatment of this pre-refined model with the SQUEEZE procedure in PLATON [Spek (2009). Acta Cryst. D65, 148-155] revealed two voids per unit cell, indicative of the presence of the solvent methanol mol-ecule disordered about the 622 inversion centre.

Bis(1,3-dimethyl-1H-imidazolium) hexa-fluoro-silicate: the second monoclinic polymorph.

The title compound, 2C5H9N2 (+)·SiF6 (2-), (I), crystallized as a new polymorph, different from the previously reported one (Ia) [Light et al. (2007 ▶) private communication (refcode: NIQFAV). CCDC, Cambridge, England]. The symmetry [space groups P21/n for (I) and C2/c for(Ia)] and crystal packing patterns are markedly different for this pair of polymorphs. In (I), all imidazolium cations in the lattice are nearly parallel to each other, whereas a herringbone arrangement can be found in (Ia). In (I), each SiF6 (2-) dianion forms four short C-H⋯F contacts with adjacent C5H9N2 (+) cations, resulting in the formation of layers parallel to the ac plane. In (Ia), the C-H⋯F contacts are generally longer and result in the formation of layers along the bc plane.

Trichlorido(tetra-hydro-furan){(1,2,3,3a,7a-η)-1-[2-(1-trimethyl-silyl-1H-imidazol-2-yl-κN)-1-methyl-prop-yl]inden-yl}zirconium(IV).

The title compound, [ZrCl(3)(C(19)H(25)N(2)Si)(C(4)H(8)O)], was prepared from bis-(N,N-dimethyl-amido-κN)(2-{2-[(1,2,3,3a,7a-η)-inden-yl]-2-methyl-prop-yl}-1H-imidazolido-κN(1))zirconium(IV) [(C(16)H(16)N(2))Zr(NMe(2))] by reaction with excess Me(3)SiCl in tetra-hydro-furan (THF) at elevated temperature. The crystal studied contained a minor non-merohedral twin contaminant [6.3 (4)%] which was taken into account during the refinement. The coordination polyhedron of the Zr(IV) atom is a distorted octa-hedron [assuming that the five-membered ring of the indenyl group (Cp) occupies one coordination site], with the Cp group and a THF O atom at the apical positions and the three Cl and ligating N atoms at the equatorial positions. The Zr, Si and the methyl-ene C atoms deviate noticeably from the imidazole ring plane [by -0.197 (5), -0.207 (5) and 0.119 (6) Å, respectively]. The THF ligand adopts an envelope conformation.

{2-[(η-Cyclo-penta-dien-yl)diphenyl-meth-yl]-1H-imidazolido-κN}bis-(N,N-diethyl-amido)-titanium(IV).

The chemically achiral title mol-ecule, [Ti(C(4)H(10)N)(2)(C(21)H(16)N(2))], crystallizes in the chiral space group P2(1). All three N atoms coordinating to the Ti(IV) atom adopt planar environments [sums of valence angles = 359.5 (6), 360.0 (7) and 360.0 (6)°], which is indicative of pπ-dπ donation from all of these N atoms to the metal and, thus, of the formal 18 e(-) nature of the complex. The overall coordination about the Ti(IV) atom is distorted tetra-hedral, assuming the cyclo-penta-dienyl ring occupies one coordination site. The Ti-N(imidazole) amide-type bond is longer by approximately 0.16 Šthan the other two Ti-N(amide) bonds.

rac-(OC-6-33)-bis-[2-(N-Benzyl-methyl-imino-meth-yl-κN)-1H-imidazol-1-ido-κN]bis(ethyl-amido)-titanium(IV).

The title compound, [[Ti(C(2)H(10)N)(2)(C(11)H(10)N(3))(2)] or Ti(C(11)H(10)N(3))(2)(NEt(2))(2)], was prepared by direct reaction of 2-(N-phenyl-methyl-imino-meth-yl)-1H-imidazole and [Ti(NEt(2))(4)]. The Ti(IV) atom is in a pseudo-octa-hedral coordination environ-ment with the imidazolido-group N-atoms occupying apical positions and amido- and imino-N-atoms cis-located in the equatorial plane. The presence of two bidentate chelating ligands determines the chirality of the Ti(IV) atom. The crystallographically independent unit, except for its phenyl rings, adopts nearly pseudo-C(2) symmetry (rotation around a twofold axis passing through the Ti atom and the centre of the imino-N⋯imino-N segment). The Ti-N(amido), Ti-N(imidazolido), and Ti-N(imino) bond lengths essentially differ, increasing by approximately 0.2 Šin the series. All ligating N atoms are in a nearly planar environment, which is indicative of additional pπ-dπ donations towards the metal atom. The two diaza-metallacyclic units are planar within 0.03 and 0.05 Å.

2-{(E)-N-[2-(1H-Inden-3-yl)eth-yl]imino-meth-yl}-1H-imidazole.

The asymmetric unit of the title compound, C(15)H(15)N(3), contains two crystallographically independent mol-ecules with very similar geometries. The imidazole and indenyl planes are approximately orthogonal, making dihedral angles of 88.21 (9) and 83.08 (9)%deg; in the two independent molecules. In the crystal, the imidazole units are linked by N-H⋯N hydrogen bonds into chains parallel to the 101) plane stretched in the diagonal direction [translation vector ([Formula: see text],1,0); C(4) motif]. Within a chain, there are two types of symmetrically non-equivalent alternating H-bonds which slightly differ in their parameters.

Scandium terminal imido complex induced C-H bond selenation and formation of an Sc-Se bond.

The reaction between scandium terminal imido complexes and elemental selenium showed an unprecedented C-H bond selenation and the formation of an Sc-Se bond.

Neodymium(III) phosphinidene complexes supported by pentamethylcyclopentadienyl and hydrotris(pyrazolyl)borate ligands.

Synthesis of new neodymium(III) phosphinidene complexes from a neodymium(III) phosphinidene iodide [(mu-PC(6)H(3)-2,6-(i)Pr(2))Nd(I)(THF)(3)](2) (1) was studied. The metathesis reaction of 1 with KC(5)Me(5) (KCp*) gave a neodymium(III) pentamethylcyclopentadienyl phosphinidene complex [(mu-PC(6)H(3)-2,6-(i)Pr(2))(C(5)Me(5))Nd(THF)](2) (2), and that with potassium hydrotris(pyrazolyl)borate KHB(3-phenylpz)(3) (KTp(Ph)) generated a neodymium(III) hydrotris(pyrazolyl)borate phosphinidene complex [(mu-PC(6)H(3)-2,6-(i)Pr(2))(Tp(Ph*))Nd(THF)](2) (3) and a C-H bond activation byproduct [kappa(4)(N,N',N'',C(Ph))-Tp(Ph)]Tp(Ph)Nd (4). Complexes 2-4 have been characterized by single-crystal X-ray diffraction analysis.

Trichlorido{2-[2-(η-cyclo-penta-dien-yl)-2-methyl-prop-yl]-1-trimethyl-silyl-1H-imidazole-κN}titanium(IV) tetra-hydro-furan hemisolvate.

The title compound, [Ti(C(15)H(23)N(2)Si)Cl(3)]·0.5C(4)H(8)O, has been prepared from {2-[2-(η(5)-cyclo-penta-dien-yl)-2-methyl-prop-yl]-1H-imidazolyl-κN(1)}bis-(N,N-diethyl-amido-κN)titanium(IV), (C(12)H(14)N(2))Ti(NEt(2))(2), by reaction with excess of Me(3)SiCl in tetra-hydro-furan (THF) at 353 K. The crystal structure contains THF as adduct solvent, disordered around a center of inversion. The presence of THF and the adduct ratio has been independently supported by (1)H NMR spectroscopy. The coordination polyhedron of the Ti atom is distorted square-pyramidal, assuming the cyclo-penta-dienyl (Cp) ring occupies one coordination site. The Ti, Si and CH(2) group C atoms only deviate slightly from the imidazole ring plane [by 0.021 (4), 0.133 (4) and 0.094 (4) Å, respectively]. Comparison of the principal geometric parameters with those of the few known structurally characterized analogues reveal small differences in bond lengths and angles at the Ti atom. The title complex is only stable in THF-d(8) in the presence of excess Me(3)SiCl, otherwise it exists in an equilibrium with equimolar amounts of dichlorido{2-[2-(η(5)-cyclo-penta-dien-yl)-2-methyl-prop-yl]-1H-imidazolyl-κN(3)}titanium(IV) and chloro-trimethyl-silane.

2-[(Cyclo-penta-1,3-dien-2-yl)diphenyl-meth-yl]-1-methyl-1H-imidazole.

The title compound, C(22)H(20)N(2), (Ib), forms along with 2-[(cyclo-penta-1,3-dien-1-yl)diphenyl-meth-yl]-1-methyl-1H-imid-azole, (Ia), which differs with respect to the position of the double-bonds in the C(5)H(5) ring, in an approximately 3:7 ratio (Ia:Ib; NMR spectroscopy data). However, in a single crystal, only compound (Ib) is present. H atoms of the CH(2) group (C(5)H(5) ring) were found from the difference Fourier synthesis and refined isotropically using the riding model. Hypothesis on possible presence of the (Ia) isomer in crystal lattice (model with a C(5)H(5) ring disordered between two positions) was especially checked and rejected due to its inconsistency. In the crystal structure, no significant hydrogen-bonding inter-actions between the CH(2) groups of the C(5)H(5) rings and nonsubstituted N-atoms of the imidazole rings were observed. Despite the fact that the chemically achiral compound (I) crystallizes in a chiral space group P2(1)2(1)2(1), neither the absolute structure determination nor assignment of the inversion twinning was possible in the absence of a heavy atom.

4-[(E)-({4-[Bis-(2-hy-droxy-eth-yl)amino]-phen-yl}imino)-meth-yl]phenol.

In the title compound, C(17)H(20)N(2)O(3), the amino N atom is in a planar environment (sum of angles = 360.0°). All hy-droxy H atoms are involved in hydrogen bonding. In the crystal structure, two O-H⋯O and an O-H⋯N(imino) hydrogen bond result in the formation of a three-dimensional network. The latter hydrogen bonding causes distortion of the planarity of the 4-HO-C(6)H(4)-CH=N-C(6)H(4)- fragment by rotation around the =N-C(Ph) bond. The crystal studied was a non-merohedral twin [refined BASF parameter for the major component = 0.5293 (7)].

2,2'-(4-{[(E)-4-Meth-oxy-benzyl-idene]amino}-phenyl-imino)-diethanol.

In the title compound, C(18)H(22)N(2)O(3), the dihedral angle between the aromatic rings is 3.9 (2)°. Both H atoms of the hy-droxy groups are involved in inter-molecular O-H⋯O hydrogen bonding. In the crystal structure, this hydrogen bonding assembles mol-ecules into chains of 2(1) symmetry extending parallel to the b axis. The almost planar (within 0.09 and 0.06 Å) 4-CH(3)O-C(6)H(4)-CH=N-C(6)H(4)- groups are oriented outwards the twofold screw axis.

Two 18e Ti(IV) eta5-Cp-tris(sec-amido)-type complexes derived from 1H-imidazol-2-yl side-chain functionalized cyclopentadienes.

Achiral {2-[2-(eta(5)-cyclopentadienyl)-2-methylpropyl]-1H-imidazolyl-kappaN(1)}bis(N,N-diethylamido-kappaN)titanium(IV), [Ti(C(4)H(10)N)(2)(C(12)H(14)N(2))], (I), and closely related racemic (SR)-{2-[(eta(5)-cyclopentadienyl)(phenyl)methyl]-1H-imidazolyl-kappaN(1)}bis(N,N-diethylamido-kappaN)titanium(IV), [Ti(C(4)H(10)N)(2)(C(15)H(12)N(2))], (II), have been prepared by direct reactions of Ti(NEt(2))(4) and the corresponding 1H-imidazol-2-yl side-chain functionalized cyclopentadienes. In compound (II), there are two crystallographically independent molecules of very similar geometries connected by a noncrystallographic pseudosymmetry operation akin to a 2(1) screw axis. All Ti-ligating N atoms in both (I) and (II) are in planar environments, which is indicative of an additional N-->Ti ppi-dpi donation. This fact and the 18e nature of both (I) and (II) are additionally supported by quantum chemical single-point density functional theory (DFT) computations.

(Diethyl ether){1-[2-(1-methyl-1H-imidazol-2-yl-κN)-1,1-diphenyl-ethyl]-(1,2,3,3a,7a-η)-inden-yl}lithium(I).

In the title compound, [Li(C(27)H(23)N(2))(C(4)H(10)O)], the Li atom possesses a nearly planar trigonal coordination environment (assuming the cyclo-penta-dienyl ring of the indenyl group occupies one coordination place). The diethyl ether ligand adopts a nearly planar W-type conformation.