A highly functionalized ferrocenyl­pyrazolo­[2,3‐a]­pyridine

The crystal structure of [2‐(4‐bromo­phenyl)‐4‐cyano‐5‐ferrocenyl­pyrazolo­[2,3‐a]­pyridin‐7‐yl]­aceto­nitrile, C₂₆H₁₇N₄FeBr or [Fe(C₅H₅)(C₂₁H₁₂BrN₄)], shows that the pyrazolo­pyridine ring system (PP), the bromo­phenyl ring (BP) and the cyclo­penta­diene ring (Cp) are nearly planar. The PP ring system is twisted out of the plane of the BP and Cp rings by about 20°.     

A five‐coordinate ruthenium(II)–porphyrin–carbene complex: [bis(3‐trifluoromethylphenyl)methylene‐κC](5,10,15,20‐tetra‐p‐tolylporphyrinato‐κ4N)ruthenium(II)

The stable title tri­fluoro­methyl‐substituted carbenyl metalloporphyrin, [Ru(C₁₅H₈F₆)(C₄₈H₃₆N₄)], has a five‐coordinate Ru atom which is displaced from the porphyrin N₄ plane towards the axial carbene ligand by 0.230 (3) Å. The Ru—C(carbene) bond coincides with a crystallographic twofold axis and its length of 1.841 (6) Å is notably shorter than the value of 1.868 (3) Å in the pyridine adduct.     

Azido­[1,1′‐bis­(di­phenyl­phosphino)­ferrocene](penta­methyl­cyclo­penta­dienyl)­rhodium(III) hexa­fluoro­phosphate

In the title compound, azido‐2κN‐bis­[μ‐(1η⁵:2κP)‐di­phenyl­phosphino­cyclo­penta­dienyl][2(η⁵)‐penta­methyl­cyclo­penta­di­enyl]­iron(III)­rhodium(III) hexa­fluoro­phosphate, [{Rh(C₁₀H₁₅)(N₃)}{Fe(μ‐C₁₇H₁₄P)₂}]PF₆ or [FeRh(C₁₀H₁₅)(μ‐C₁₇H₁₄P)₂(N₃)]PF₆, the coordination sphere of Rh^III can be described as pseudo‐tetrahedral, composed of two P atoms from a 1,1′‐bis­(di­phenyl­phosphino)­ferrocene (dppf) ligand, an azido N atom and the centroid of the ring of a C₅Me₅ (Cp*) ligand. The two cyclo­penta­dienyl rings in the dppf moiety adopt an eclipsed conformation. The Rh⋯Fe distance is 4.340 (2) Å.     

The dimeric mixed‐ligand titana­carborane sandwich [1‐(Cp)‐1‐Ti‐2‐(Me)‐3‐(SiMe3)‐2,3‐C2B4H4]2

The title dimer, bis­[1‐cyclo­penta­dienyl‐2‐methyl‐1‐titana‐3‐tri­methylsilyl‐2,3‐dicarba‐closo‐hexaborane(6)], [Ti(C₅H₅)(C₆­H₁₆­B₄Si)]₂, reveals that the centrosymmetric mol­ecule consists of two bent‐sandwich titanacarboranes bridged by the B—H—Ti bonds. The average bond distances are Ti—B 2.445 (3), Ti—C(cage) 2.334 (2) and Ti—C(Cp) 2.376 (3) Å, and the corresponding bond angles are Cp—Ti—Cp 163.2 (1) and Cp—Ti—Cb (Cb = C₂B₃ face) 139.9 (1)°; the Ti—H separations are 2.10 (2) and 2.19 (2) Å.     

The new polynuclear titanium(IV) complex [(Cp*TiCl)(μ‐O)2(Cp*Ti)2(μ‐O)(μ‐O)2]2Ti (Cp* is η5‐C5Me5)

A new polynuclear titanium(IV) complex, dichloro­deca‐μ₂‐oxo‐hexa­kis­(penta­methyl­cyclo­penta­dien­yl)hexa­titanium(IV), [Ti₆(C₁₀H₁₅)₆Cl₂O₁₀], has been synthesized by hydro­lysis of a titanium complex bearing an N‐(2‐hydr­oxy‐3,5‐dimethyl­benz­yl)diethano­lamine Mannich ligand. The mol­ecule has two O‐bridged Ti₃O₃ rings linked to two similar rings through a tetra­hedrally O‐coordinated Ti atom. All Ti atoms except the central one are coordinated to penta­methyl­cyclo­penta­dien­yl (Cp*) ligands. The Cp* ligands are arranged with approximate symmetry with respect to the Ti/O/Cl core.     

[(η5‐C5R5)TiCl2(η5‐C5H4SiMe2)]2O·nCH2Cl2

The first title metallocene, 1,3‐bis(dichlorotitanocene)‐1,1,3,3‐tetramethyldisiloxane dichloromethane solvate, [(η⁵‐C₅H₅)­TiCl₂­(η⁵‐C₅H₄­Si­Me₂)]₂O·­CH₂Cl₂, (I), crystallizes in space group P2₁/c. Compound (I) represents the first crystal structure of a bimetallic siloxy‐bridged titanocene. The geometric parameters of (I) are similar to those of the parent titanocene; however, the disiloxane substituents adopt an unexpected eclipsed conformation. The second title metallocene, 1,3‐bis­[(penta­methyl­cyclo­penta­dienyl)­(cyclo­penta­dien­yl)­titanium dichloride]‐1,1,3,3‐tetra­methyl­disiloxane, [(η⁵‐C₅‐Me₅)­TiCl₂­(η⁵‐C₅H₄­Si­Me₂)]₂O, (II), represents the second crystal structure of a bimetallic siloxy‐bridged titanocene and crystallizes in the space group P2₁/n. Compound (I) possesses non‐crystallographic twofold molecular symmetry and both metal centers adopt pseudo‐tetrahedral geometries. The geometric parameters of (II) are similar to those of the mixed titanocene Cp*CpTiCl₂ (Cp* = C₅Me₅) and the disiloxane substituents adopt a staggered conformation.     

(Nitro‐κN)[2‐(phenyldiazenyl‐κN2)pyridine‐κN](2,2′:6′,2′′‐terpyridine‐κ3N)ruthenium(II) tetrafluoroborate

The Ru—N bond distances in the title complex, [Ru(NO₂)(C₁₁H₉N₃)(C₁₅H₁₁N₃)]BF₄ or [Ru(NO₂)(tpy)(azpy)]BF₄, [tpy is 2,2′:6′,2′′‐ter­pyridine and azpy is 2‐(phenyl­azo)­pyridine], are Ru—N_py 2.063 (4), Ru—N_azo 2.036 (4), Ru—N_nitro 2.066 (3) Å, and Ru—N_tpy 2.082 (4), 1.982 (3) and 2.074 (4) Å. The azo N atom is trans to the nitro group. The azo N=N bond length is 1.265 (5) Å, which is the shortest found in such complexes to date. This indicates a multiple bond between Ru and the N atom of the nitro group, and π‐­backbonding [dπ(Ru) π*(azo)] is decreased.     

(E)‐2‐(2‐Adamantylidene)‐3‐(1‐ferrocenylethylidene)succinic anhydride

The title compound, [Fe(C₅H₅)(C₂₁H₂₁O₃)], was obtained from successive Stobbe condensations between ketones and di­methyl succinate. The succinic anhydride five‐membered ring is distorted significantly from planarity, with the buta­diene moiety being twisted by 49.3 (2)° from planarity and the C atoms at the succinic anhydride end of the alkene bonds showing significant pyramidalization. The cyclo­penta­diene rings of the ferrocenyl moiety adopt an almost eclipsed conformation.     

(η6‐Hexamethylbenzene)(mesidine)­ditriflatoruthenium(II)

The crystal structure of the title complex, (η⁶‐hexamethylbenzene)bis(trifluoromethanesulfonato‐O)(2,4,6‐trimethylanil­ine‐N)ruthenium(II), [Ru(CF₃O₃S)₂(C₁₂H₁₈)(C₉H₁₃N)], is described. The complex has the classic three‐legged piano‐stool structure with a planar arene 1.667 Å from the metal, two monodentate O‐bound tri­fluoro­methane­sulfonate ligands [Ru—O 2.169 (2) and 2.174 (2) Å] and one N‐bound mesidine ligand [Ru—N 2.198 (2) Å]. The Ru—N distance is relatively long and the average Ru—O distance is relatively short when compared with previously characterized Ru^II complexes.     

(η5‐Cyclo­penta­dienyl)(p‐fluoro­phenoxo)(nitro­syl)(tri­methyl­silyl­methyl)­molybdenum(II)

The title complex, [Mo(C₅H₅)(C₆H₄FO)(C₄H₁₁Si)(NO)], is formed by reacting CpMo(NO)(CH₂SiMe₃)₂, where Cp is cyclo­penta­dienyl, with one equivalent of p‐FC₆H₄OH. The complex exhibits the expected piano‐stool molecular structure, with a linear nitro­syl ligand [Mo—N—O 168.2 (2)°] having Mo—N and N—O distances of 1.764 (2) and 1.207 (3) Å, respectively. The phenoxo Mo—O distance of 1.945 (2) Å is suggestive of some multiple‐bond character.     

Pentamethylcyclopentadienyl(η6‐cyclooctatrienyl)ruthenium Tetrachlorozincate, [RuCp*(η6‐C8H10)]2ZnCl4

The crystal and molecular structures of the title compound, the first for a complex of the type [RuCp*(η⁶‐C₈‐ring)]⁺, is presented, the material being obtained serendipitously from a reaction between RuCl(cod)Cp* and 1‐ferrocenylbuta‐1,3‐diyne in the presence of ZnCl₂. <Ru‐C(Cp*)> (2.21 Å) is appreciably longer than in RuCp*₂ (2.18 Å) and similar to the value for the Ru‐η⁶ component (2.22 Å).     

Di‐μ‐methoxy‐bis[(η5‐cyclopentadienyl)(nitrosyl‐κN)(trimethylsilylmethyl)molybdenum(II)]

The title complex, [Mo₂(C₅H₅)₂(CH₃O)₂(C₄H₁₁Si)₂(NO)₂], is formed in high yield by treating [CpMo(NO)(CH₂SiMe₃)₂] (Cp is cyclo­penta­dienyl) with methanol. The nitro­syl ligands are nearly linear [O—N—Mo 170.1 (4) and 170.1 (5)°], with short Mo—N bonds [1.769 (4) and 1.776 (4) Å] and long N—O bonds [1.216 (5) and 1.201 (4) Å]. The central four‐membered Mo₂O₂ ring exhibits an average Mo—O bond length of 2.15 Å.     

Disordered syn–anti hydrogen‐bonded chains in 3‐(ferrocenyl­carbonyl)­propionic acid

The title compound, [Fe(C₅H₅)(C₉H₉O₃)], has Fe–centroid distances of 1.6551 (11) and 1.6445 (11) Å to the cyclo­penta­dienyl rings. The carboxyl group forms hydrogen bonds in the extremely rare syn–anti chain motif, with O⋯O distances of 2.667 (3) and 2.655 (3) Å. The carboxyl group and the hydrogen‐bonded chains are disordered.     

Tri­benzyl{η5‐[2‐(p‐tolyl)­prop‐2‐yl]­cyclo­penta­dienyl}­zirconium

The title compound, [Zr(C₇H₇)₃(C₁₅H₁₇)], (I), crystallizes from light petroleum with two independent mol­ecules in the asymmetric unit. Whereas in the parent mol­ecule, Zr(η⁵‐C₅H₅)(CH₂Ph)₃, all three Zr—CH₂Ph angles are equal, in (I), they differ significantly. In spite of their different environments, both independent mol­ecules in (I) exhibit a small, an expected, and a large Zr—CH₂Ph angle. The angles are similar to those of the closely related tri­benzyl­[η⁵‐(benzyl­di­methyl­silyl)­cyclo­penta­dienyl]­zirconium complex. The smallest Zr—CH₂Ph angle and the consequently relatively short Zr?C_ipso distance are indicative of η²‐bonding of the benzyl group.     

A chloro(2‐pyridinecarboxaldehyde)(2,2′:6′,2′′‐ter­pyridine)­ruthenium(II) complex

The aldehyde moiety in the title complex, chloro(2‐pyridinecarboxaldehyde‐N,O)(2,2′:6′,2′′‐terpyridine‐κ³N)ruthenium(II)–chloro­(2‐pyridine­carboxyl­ic acid‐N,O)(2,2′:6′,2′′‐ter­pyridine‐κ³N)­ruthenium(II)–perchlorate–chloro­form–water (1.8/0.2/2/1/1), [RuCl­(C₆H₅NO)­(C₁₅H₁₁N₃)]_1.8[RuCl­(C₆H₅­NO₂)(C₁₅H₁₁N₃)]_0.2­(ClO₄)₂·­CHCl₃·­H₂O, is a structural model of substrate coordination to a transfer hydrogenation catalyst. The title complex features two independent Ru^II complex cations that display very similar distorted octahedral coordination provided by the three N atoms of the 2,2′:6′,2′′‐ter­pyridine ligand, the N and O atoms of the 2‐pyridine­carbox­aldehyde (pyCHO) ligand and a chloride ligand. One of the cation sites is disordered such that the aldehyde group is replaced by a 20 (1)% contribution from a carboxyl­ic acid group (aldehyde H replaced by carboxyl O—H). Notable dimensions in the non‐disordered complex cation are Ru—N 2.034 (2) Å and Ru—O 2.079 (2) Å to the pyCHO ligand and O—C 1.239 (4) Å for the pyCHO carbonyl group.     

[η5,σ‐3,3‐Di­methyl‐1‐(2,3,4,5‐tetra­methyl­cyclo­penta­dienyl)­but‐1‐en‐2‐amino](η5‐penta­methyl­cyclo­penta­dienyl)titanium

The titanocene complex [Ti(C₁₀H₁₅)(C₁₅H₂₃N)] features a penta­methyl­cyclo­penta­dienyl ligand and a substituted cyclo­penta­dienyl ligand Me₄C₅R, where R is an amino functional group which is subsequently attached to the titanium metal centre. The structure has been determined to ascertain the conformational properties of the side chain with regard to extended conjugation between the π systems and the nature of the amino interaction with the metal centre.     

[μ‐1κ2O,O′:2(η5)‐Cyclopentadienylcarboxylato][2(η5)‐diphenylphosphinocyclopentadienyl]bis[1,1(η5)‐tetramethylcyclopentadienyl]iron(II)titanium(III)

Reacting stoichiometric amounts of 1‐(diphenylphosphino)ferrocene­carboxylic acid and [Ti(η⁵‐C₅HMe₄)₂(η²‐Me₃SiC[triple‐bond]CSiMe₃)] produced the title carboxyl­atotitanocene complex, [{μ‐1κ²O,O′:2(η⁵)‐C₅H₄CO₂}{2(η⁵)‐C₅H₄P(C₆H₅)₂}{1(η⁵)‐C₅H(CH₃)₄}₂Fe^IITi^III] or [FeTi(C₉H₁₃)₂(C₆H₄O₂)(C₁₇H₁₄P)]. The angle subtended by the Ti/O/O′ plane, where O and O′ are the donor atoms of the κ²‐carboxy­late group, and the plane of the carboxyl‐substituted ferrocene cyclo­penta­dienyl is 24.93 (6)°.     

The trans influence of the pyridine ligand on ruthenium(II)–porphyrin–carbene complexes

In the two ruthenium(II)–porphyrin–carbene complexes ­(di­benzoyl­carbenyl‐κC)(pyridine‐κN)(5,10,15,20‐tetra‐p‐tolyl­porphyrinato‐κ⁴N)­ruthenium(II), [Ru(C₁₅H₁₀O₂)(C₅H₅N)(C₄₈H₃₆N₄)], (I), and (pyridine‐κN)(5,10,15,20‐tetra‐p‐tolyl­porphyrinato‐κ⁴N)[bis(3‐tri­fluoro­methyl­phenyl)­carbenyl‐κC]­ruthenium(II), [Ru(C₁₅H₈F₆)(C₅H₅N)(C₄₈H₃₆N₄)], (II), the pyridine ligand coordinates to the octahedral Ru atom trans with respect to the carbene ligand. The C(carbene)—Ru—N(pyridine) bonds in (I) coincide with a crystallographic twofold axis. The Ru—C bond lengths of 1.877 (8) and 1.868 (3) Å in (I) and (II), respectively, are slightly longer than those of other ruthenium(II)–porphyrin–carbene complexes, owing to the trans influence of the pyridine ligands.     

Dichloro{N‐[3‐(η5‐cyclopentadienyl)propyl]‐4‐toluenesulfonamido‐κ2N,O}titanium(IV)

The title compound, [Ti(C₁₅H₁₇NO₂S)Cl₂], has a Ti atom bound to the N and O atoms of a p‐toluene­sulfon­amide ligand, which is tethered by a three‐carbon chain to a η⁵‐cyclo­penta­dienyl group. The distorted square‐pyramidal geometry is completed by two Cl atoms. The Ti—N bond length of 2.0375 (13) Å is longer than that in related compounds, the N atom having asymmetric trigonal–planar geometry. Conformational strain relief is noted when compared with ethyl‐tethered compounds.     

[(8a,9,9a‐η)‐9‐(η5‐Cyclopentadienyl)‐9‐nickelafluorenyl](η5‐pentamethylcyclopentadienyl)nickel(II)

The title compound, [Ni₂(C₅H₅)(C₁₀H₁₅)(C₁₂H₈)] or [Ni(C₁₀H₁₅){Ni(C₅H₅)(C₁₂H₈)}], is a rare example (and the first obtained from nickelafluorenyllithium) of an analogue of nickelocene in which the central Ni atom is coordinated to one pentamethylcyclopentadienyl ring and one nickelafluorenyl ring. Both rings lie almost parallel to one another: the dihedral angle between the planes which include these rings is 4.4 (1)°. Slip parameter analysis indicates that the bonding mode of the central Ni atom to the nickelacyclic ring is between η³ and η⁵. Two‐dimensional layers of molecules are formed by C—H...π interactions.