Intermolecular O—H⃛O and C—H⃛π(C5H5), and intramolecular C—H⃛O interactions in 2-(ferrocenyl)thiophene-3-carboxylic acid

The title compound, [Fe(C₅H₅)(C₁₀H₇O₂S)], an important precursor en route to organometallic donor–π–acceptor systems, forms dimers in the solid state through cyclic intermolecular carboxyl­ic acid O—H⃛O hydrogen bonds, graph set R(8) [O⃛O 2.661 (2) Å and O—H⃛O 175°]. Intermolecular C_Cp—H⃛π_Cp interactions between the unsubstituted cyclo­penta­dienyl (Cp) rings and C_thiazole—H⃛π_Cp interactions link neighbouring mol­ecules into a three-dimensional network [C⃛Cg 3.753 (7) Å and C—H⃛Cg 156°, and C⃛Cg 3.687 (3) Å and C—H⃛Cg 129°; Cg is the ring centroid]. Intramolecular C—H⃛O inter­actions are present, graph set S(7) [C⃛O 2.925 (3) Å and C—H⃛O 120°, and the closest C—H⃛S_thienyl contact has a C⃛S distance of 3.058 (2) Å].     

Ferrocene compounds. XXXVIII. Di­methyl ferrocene‐1,1′‐di­carboxyl­ate

In the title compound, [Fe(C₇H₇O₂)₂], the cyclo­penta­dienyl rings and the two attached methoxy­carbonyl groups, in an anti arrangement, form an extended π‐conjugated system. The Fe—C distances range from 2.035 (3) to 2.061 (3) Å and the average value of the C—C bond lengths in the two cyclo­penta­dienyl rings is 1.419 (5) Å. The rings are almost parallel to one another [1.0 (2)°] and are mutually twisted from an eclipsed conformation by only 1.8 (3)° (average value). The methoxy­carbonyl groups are twisted out of the plane of the cyclo­penta­dienyl rings by 6.5 (4) and 15.7 (4)°, respectively. The mol­ecules are joined into dimers by intermolecular C—H⃛O hydrogen bonds that form ten‐membered rings. The same types of hydrogen bonds form eight‐membered rings and infinite chains along the b axis.     

N‐(o‐Chloro­phenyl)‐2,5‐di­methyl­pyrrole‐3‐carb­aldehyde

Crystal structure analysis of the title compound, C₁₃H₁₂ClNO, reveals three crystallographically independent mol­ecules in the asymmetric unit. The main conformational difference between these mol­ecules is the orientation of the phenyl rings with respect to the pyrrole rings. The coplanar arrangement of the aldehyde groups attached to the pyrrole rings influences the pyrrole‐ring geometry. The C2—C3 and N1—C5 bonds are noticeably longer than the C4—C5 and N1—C2 bonds. Two independent mol­ecules of the title compound form dimers via intermolecular C—H⃛O hydrogen bonds [D⃛A = 3.400 (3) Å and D—H⃛A = 157°]. The perpendicular orientation of the phenyl and pyrrole rings of one independent mol­ecule and its symmetry‐related mol­ecule allows C—H⃛π interactions, with an H⃛centroid distance of 2.85 Å and a C—H⃛π angle of 155°. The distances between the H atom and the pyrrole‐ring atoms indicate that the C—H bond points towards one of the bonds in the pyrrole ring.     

Three ruthenocene derivatives: (η5‐4,7‐dimethylindenyl)(η5‐pentamethylcyclopentadienyl)ruthenium(II), [η5‐[2](4,7)indeno[2]paracyclophanyl](η5‐pentamethylcyclopentadienyl)ruthenium(II) and bis[η5‐[2](4,7)indeno[2]paracyclophanyl]­ruthenium(II)

In the title compounds, [Ru(C₁₀H₁₅)(C₁₁H₁₁)], (III), [Ru(C₁₀H₁₅)(C₁₉H₁₇)], (IV), and [Ru(C₁₉H₁₇)₂], (V), respectively, the coordinating ring systems are planar and parallel, with the Ru atoms lying at perpendicular distances of Ru–Cp* 1.790 (1) Å and Ru–indenyl 1.836 (1) Å in (III), Ru–Cp* 1.791 (1) Å and Ru–indenyl 1.837 (1) Å in (IV), and Ru–indenyl 1.812 (1) Å and 1.809 (1) Å in (V) (Cp* is penta­methyl­cyclo­penta­dienyl). The ring conformations are eclipsed for (III), staggered for (IV) and intermediate for (V). All three compounds show short intermolecular contacts from C—H groups to some ring centroids; these could be regarded as C—H?π hydrogen bonds. The mol­ecules of each compound are thus connected via the 2₁ screw axis to form layers parallel to the xy plane.     

Charge‐assisted N—H·I and C—H·I hydrogen bonding in (1R,2S)‐1‐(ferrocenylmethyl)‐2‐(methoxymethyl)pyrrolidinium iodide

In the title compound, [Fe(C₅H₅)(C₁₂H₁₉NO)]I, the ferrocene moiety has an eclipsed conformation, with mean Fe—C bond lengths of 2.031 (4) and 2.020 (6) Å for the substituted and unsubstituted cyclo­penta­dienyl rings. The pyrrolidinium heterocycle adopts an envelope conformation and has its 1‐ and 2‐substituents in a relative trans disposition. Strong (+/−)‐charge‐assisted N—H·I and C—H·I hydrogen bonds are present. The crystal structure is also stabilized by weak C—H·O interactions.     

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.     

[{Me4C2(C5H4)2}Zr(BH4)2], a bis(tetra­hydro­borate) complex of a bridged zirconocene

Bis(tetra­hydro­borato)­[1,1,2,2‐tetra­methyl‐1,2‐ethyl­enebis­(η⁵‐cyclo­penta­dienyl)]­zirconium, (I), was synthesized by the reaction of the zirconocene dichloride with lithium tetra­hydro­borate. Crystals suitable for X‐ray structure analysis were obtained by recrystallization from toluene. The mol­ecule adopts an appproximate C_2v symmetry. Both tetra­hydro­borate ligands are η²‐coordinated and tilted by 18–19° out of the equatorial plane; the angle B1—Zr1—B2 is 104.7°. The cyclo­penta­dienyl rings show a normal η⁵‐coordinaton, with a centroid–Zr–centroid angle of 124.3°.     

1‐Acetyl‐3‐ferrocenyl‐5‐methyl‐1H‐pyrazole and 1‐acetyl‐5‐ferrocenyl‐3‐(2‐pyrid­yl)‐1H‐pyrazole

Mol­ecules of 1‐acetyl‐3‐ferrocenyl‐5‐methyl‐1H‐pyrazole, [Fe(C₅H₅)(C₁₁H₁₁N₂O)], form a centrosymmetric dimer generated by a combination of one C—H⋯π(pyrazole) and one C—H⋯π(cyclo­penta­dienyl) inter­action. The dimers are linked by C—H⋯π inter­actions, involving the pyrazole rings as acceptors, into layers parallel to (10). Mol­ecules of 1‐acetyl‐5‐ferrocenyl‐3‐(2‐pyrid­yl)‐1H‐pyrazole, [Fe(C₅H₅)(C₁₅H₁₂N₃O)], are linked by C—H⋯O inter­actions into a chain running in the [010] direction. Two chains of this type passing through each unit cell are connected by O⋯π(pyridyl) inter­actions into an [010] double chain.     

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.     

(2S,4S,SFc)-2-[2-(Diphenyl­thio­phosphinoyl)­ferrocenyl]-4-methoxy­methyl-1,3-dioxane

The title compound, [Fe(C₅H₅)(C₂₃H₂₄O₃PS)], is a very useful inter­mediate for the synthesis of enanti­omerically pure (S)-2-[(diphenyl­thio­phosphinoyl)ferrocenyl]methanol or (S)-2-(diphenyl­thio­phosphinoyl)ferrocene­carboxaldehyde. The dioxane ring has a chair conformation and is twisted with respect to the cyclo­penta­dienyl ring to which it is attached. There is an inter­molecular C—H⋯O hydrogen-bonding inter­action which links the mol­ecules into C(8) chains developing parallel to the a axis. Owing to this weak inter­action, the two cyclo­penta­dienyl rings are twisted with respect to each other by 16.0 (3)°, and so have a conformation which might be regarded as inter­mediate between eclipsed and staggered. The absolute configuration deduced from the X-ray analysis fully confirms the sterochemistry expected from the chemical pathway.     

N‐{4‐Bromo‐2‐[(3‐bromo‐1‐phenylsulfonyl‐1H‐indol‐2‐yl)methyl]‐5‐methoxyphenyl}acetamide

In the title compound, C₂₄H₂₀Br₂N₂O₄S, the indole ring system is planar and the S atom has a distorted tetrahedral configuration. The sulfonyl‐bound phenyl ring is orthogonal to the indole ring system and the conformation of the phenyl­sulfonyl substituent with respect to the indole moiety is influenced by intramolecular C—H⃛O hydrogen bonds involving the two sulfonyl O atoms. The mean plane through the acetyl­amido group makes a dihedral angle of 57.0 (1)° with the phenyl ring of the benzyl moiety. In the crystal, glide‐related mol­ecules are linked together by N—H⃛O hydrogen bonds and C—H⃛π interactions to form molecular chains, which extend through the crystal. Inversion‐related chains are interlinked by C—H⃛π interactions to form molecular layers parallel to the bc plane. These layers are interconnected through π–π interactions involving the five‐ and six‐membered rings of the indole moiety.     

ansa‐[(tert‐Butylamino)(isodicyclo­pentadienyl)dimethylsilane]Zr(NMe2)2 prepared by an amine‐elimination reaction

An amine‐elimination reaction was used to obtain the title compound, i.e. (N‐tert‐butyl‐N‐{[(1,2,3,3a,7a‐η)‐4,5,6,7‐tetra­hydro‐4,7‐methano‐1H‐inden‐2‐yl]­di­methyl­silyl}amido‐κN)bis(N‐methyl­methanaminato‐κN)­zirconium(IV) or [isodiCpSiMe₂N‐tert‐butyl]Zr(NMe₂)₂ (Cp is cyclo­penta­dienyl), [Zr(C₁₆H₂₅NSi)(C₂H₆N)₂], in very good yield. Treatment of isodiCpHSiMe₂NH‐tert‐butyl with Zr(NMe₂)₄ leads to the formation of a yellow solid that can be purified by sublimation. The single‐crystal structure of the product shows the exo complexation of the isodi­cyclo­penta­dienyl ligand to the Zr atom. The Cp portion of this ligand is bonded to the Zr atom in a η⁵ manner, with a Zr—Cg (Cg is the ring centroid) distance of 2.2352 (10) Å. The isodiCpSiMe₂N‐tert‐butyl ligand has a constrained geometry, which is exhibited by the small angle of 95.55 (10)° for N—Si—C_Cp.     

9,9‐Dimethoxy‐7,11‐diphenyl‐2,4‐diazaspiro[5.5]undecane‐1,3,5‐trione monohydrate

Due to steric repulsions, the cyclo­hexane ring in the title compound, C₂₃H₂₄N₂O₅·H₂O, shows some bond‐length abnormalities and adopts a chair conformation. The pyrimidine and cyclo­hexane rings are approximately perpendicular to each other, and the phenyl rings are equatorial. C—H?π and N—H?O intermolecular interactions, as well as C—H?O inter‐ and intramolecular interactions, occur between the mol­ecules. In addition to van der Waals interactions, the water mol­ecule interacts with the pyrimidine­trione ring to stabilize the structure.     

Two bis­(ammonium) 1,5‐naphthalene­disulfonate salts

The title compounds, bis­(ammonium) naphthalene‐1,5‐di­sul­fon­ate, 2NH₄⁺·C₁₀H₆O₆S₂²⁻, and bis­[1‐(hydroxy­methyl)‐3,5,7‐tri­aza‐1‐azoniatri­cyclo­[3.3.1.1^3,7]­decane] 1,5‐naphthalene­di­sul­fon­ate, 2C₇H₁₅N₄O⁺·C₁₀H₆O₆S₂²⁻, were prepared from the acid‐promoted reaction of hexa­methyl­enetetr­amine. In both structures, the di­sulfonate anion is positioned on an inversion center, with each sulfonate group contributing to the supramolecular assemblies via hydrogen bonds. The ammonium cations are linked to sulfonate groups by four distinct N⁺—H⃛⁻O—S contacts [N⃛O = 2.846 (2)–2.898 (2) Å and N—H⃛O = 160 (2)–175 (2)°], whereas the 1‐(hydroxy­methyl)‐3,5,7‐tri­aza‐1‐azoniatri­cyclo­[3.3.1.1^3,7]­decane cations form one O—H⃛⁻O—S [O⃛O = 2.628 (2) Å and O—H⃛O = 176°] and three C—H⃛⁻O—S [C⃛O = 3.359 (2)–3.380 (2) Å and C—H⃛O = 148–155°] interactions to neighboring sulfonate groups.     

4‐Iodo‐N‐(2‐nitro­phenyl­sulfanyl)­aniline: π‐stacked sheets generated by a combination of N—H⃛O and C—H⃛O hydrogen bonds

Molecules of the title compound, C₁₂H₉IN₂O₂S, are linked by one N—H⃛O hydrogen bond [H⃛O = 2.16 Å, N⃛O = 2.935 (4) Å and N—H⃛O 147°] and two C—H⃛O hydrogen bonds [H⃛O both 2.49 Å, C⃛O = 3.231 (5) and 3.220 (5) Å, and C—H⃛O = 135 and 134°] into sheets which themselves are weakly linked by an aromatic π–π‐stacking interaction between iodinated rings in centrosymmetrically related mole­cules. There are no iodo–nitro interactions.     

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.     

1,3‐Bis(4‐nitro­phenyl)­triazene

The structure of the title compound, C₁₂H₉N₅O₄, reveals an almost planar mol­ecule (r.m.s. deviation = 0.061 Å), in which the interplanar angle between the phenyl rings is 5.7 (1)° and the largest interplanar angle is that between the phenyl ring and the nitro group of one of the 4‐nitro­phenyl substituents [8.8 (3)°]. The observed mol­ecular conformation suggests a delocalization of π‐electrons extended over the diazo­amine group and the terminal aryl substituents. Intermolecular N—H⃛O interactions between the twofold screw‐related mol­ecules give rise to helical chains along the [010] direction. Intermolecular C—H⃛O interactions then generate sheets of mol­ecules in the (10) plane, and these sheets are held together by N⃛C and O⃛O π–π interactions.     

The epimeric 9‐oxobicyclo[3.3.1]nonane‐3‐carboxylic acids: hydrogen‐bonding patterns of the endo acid and the lactol of the exo acid

The two δ‐keto carboxylic acids of the title, both C₁₀H₁₄O₃, are epimeric at the site of carboxyl attachment. The endo (3α) epimer, (I), has its keto‐acid ring in a boat conformation, with the tilt of the carboxyl group creating conformational chirality. The mol­ecules form hydrogen bonds by centrosymmetric pairing of carboxyl groups across the corners of the chosen cell [O⃛O = 2.671 (2) Å and O—H⃛O = 179 (2)°]. Two close intermolecular C—H⃛O contacts exist for the ketone. The exo (3β) epimer exists in the closed ring–chain tautomeric form as the lactol, 8‐hydroxy‐9‐oxatri­cyclo­[5.3.1.0^3,8]­undecan‐10‐one, (II). The mol­ecules have conformational chirality, and the hydrogen‐bonding scheme involves intermolecular hydroxyl‐to‐carbonyl chains of mol­ecules screw‐related in b [O⃛O = 2.741 (2) Å and O—H⃛O = 177 (2)°].     

(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.