Hydrosilylation reactions catalysed by decacarbonyldimanganese(O)

Decacarbonyldimanganese(O) complex, Mn₂(CO)₁₀, has been evaluated as a catalyst for hydrosilylation reactions of 1-hexene with tertiary silanes, Et₃SiH and (EtO)₃SiH. The reaction of Et₃SiH appears to be first order with respect to the catalyst, to the hexene and to the silane, although catalyst deactivation occurs when relatively high silane concentrations are used. The reaction rate is slightly affected by varying the type of the silane used. The rate of disappearance of the tertiary silane is consistent with that of the 1-hexene, which means that the catalyst is selective to hydrosilylation reactions. This was confirmed by following the rates of disappearance of Si-H and CC IR bands at 2210, 2100 and 1650 cm⁻¹ for (EtO)₃SiH, Et₃SiH and 1-hexene respectively. A comparison of the behaviour of Mn₂(CO)₁₀ with that of Co₂(CO)₈ is reported here, together with a suggested mechanism for the manganese catalyst.     

Chemical transformations of 1,3,3,5-tetrachlorononane initiated by Fe(CO)5, Me(CO)6 and Mn2(CO)10 systems

Conclusions A study was carried out on the competitive reactions of CICH₂CH₂ClCH₂CHClC₄H₉ (A) generated from 1,3,3,5-tetrachlorononane by the action of Fe(CO)₅, Mo(CO)₆, and Mn₂(CO)₁₀ systems. The Mn₂(CO)₁₀ systems were most efficient for obtaining the reaction of (A) radicals with hydrogen donors, while the Fe(CO)₅ systems were most efficient for obtaining rearrangements of (A) radicals with 1,5- and 1,6-hydrogen migration and subsequent reaction with a chlorine donor and Mo(CO)₆ and Mn₂(CO)₁₀ systems were most efficient in effecting disproportionation of (A) radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2623–2626, November, 1984.     

Darstellung von M2Mn4(CO)18(M=In,Ga) und M2Mn4(CO)18 · 2 D (M  In,D  Pyridin,Aceton; M  Ga,D  Pyridin)

Clusters of the type M₂Mn₄(CO)₁₈ with main Group III metals (M  In, Ga) have been synthesized for the first time by allowing the metals to react in a bomb tube with Mn₂(CO)₁₀, Hg[Mn(CO)₅]₂, or Hg and Mn₂(CO)₁₀; In₂Mn₄(CO)₁₈ also was formed by thermolysis of In[Mn(CO)₅]₃ in the presence of xylene. All M₂Mn₄(CO)₁₈ compounds were shown by X-ray analysis to be isomorphous (space group I4₁/a). They contain a planar bridged ring of 2M and 2 Mn atoms, in which 2 Mn(CO)₄ groups form the MnMn bond, each being connected with 2 [μ-MMn(CO)₅] units; the Mn(CO)₅ ligands at M have trans-positions with respect to the planar metal ring. The new clusters coordinate donor molecules such as pyridine or acetone at M (coordination number 3) to form complexes M₂Mn₄(CO)₁₈ · 2 D (M  In, D  pyridine, acetone; M  Ga, D  pyridine), with M having a coordination number of 4. In pyridine dissociation of Mn(CO)₅^? anions takes place without decomposition of the metal ring.Hg[Mn(CO)₅]₂ was prepared using a new method by reaction of Hg with Mn₂(CO)₁₀ in a bomb tube.     

Complexes in polymers II: FT-IR spectra,iodine oxidation,and photochemistry of [(η5-C5H)Fe(CO)2]2, [(η5-C5H5)Mo(CO)3]2 and Mn2(CO)10 in polystyrene,poly(methyl methacrylate) and polystyrene–polyacrylonitrile copolymer

The infrared spectra of [CpFe(CO)₂]₂, [CpMo(CO)₃]₂ and Mn₂(CO)₁₀ (Cp=η-C₅H₅) embedded in films of polystyrene (PS), poly(methyl methacrylate) (PMMA), and polystyrene-polyacrylonitrile (PS? AN), are comparable with those of the dimers in toluene, ethyl acetate and acetonitrile, respectively. Irradiation of the embedded dimers with UV light led to decomposition in PS and PMMA, while in PS? AN the complexes Cp₂Fe₂(CO)₃PS? AN and Mn₂(CO)₉PS? AN were formed, wherein a pendant nitrile group is coordinated to one of the metal atoms. Exposure of the embedded dimers to iodine vapour gave CpFe(CO)₂I, CpMo(CO)₃I and Mn(CO)₅I with the reaction being much slower in PMMA than in PS.     

Zinn(IV)-Mangancarbonyl-Cluster mit offener und geschlossener Metall–Metall-Verknüpfung aus Umsetzungen von SnX2 (X = Halogen) mit Mn2(CO)10

The Formation of Tin(IV)-Manganesecarbonyl Clusters with Open and Closed Metal?Metal Skeleton by Reaction of SnX₂ (X = Halogen) with Mn₂(CO)₁₀ The oxidative addition of SnX₂ (X = Br, I) and Mn₂(CO)₁₀ results in the product X₂Sn[Mn(CO)₅]₂, the clusters of this type are final reaction products in a bomb tube. The starting materials SnX₂ (X = Cl, Br, I) and Mn₂(CO)₁₀ lead in a manifold CO overpressure discharged Schlenk tube mainly to the formation of th new clusters of the type Mn₂(CO)₈[μ-Sn(X)Mn(CO)₅]₂ (X = Cl, Br, I). It was possible to prepare Mn₂(CO)₈[μ-Sn(Br)Mn(CO)₅]₂ by an application of the Schlenk tube technique with the reaction systems: Br_4?nSn[Mn(CO)₅]_n (n = 1, 2)/Mn₂(CO)₁₀ (or BrMn(CO)₅)/Xylol and BrSn[Mn(CO)₅]₃/Xylol. FSn[Mn(CO)₅]₃ could be prepared with SnF₂ and Mn₂(CO)₁₀ in a bomb tube.     

Mechanism of the photochemistry of Mn2(CO)10 in the presence of para- and ortho-quinones

The photochemical reaction of Mn₂(CO)₁₀ with para- and ortho-quinones has been studied by ESR spectroscopy in tetrahydrofuran, CH₃CN, and in 10⁻¹ M pyridine in toluene. The p-quinone (2,6-di-t-butyl-1,4-benzoquinone) has been found to undergo an electron transfer with photogenerated [Mn(CO)_{6 − n} (S)_n]^. radicals, n = 1–3, 19 e⁻ spcies producing [Mn^I(CO)_{6 − n}(S)⁺_n] · [p-semiquinone anion-radical] ion-pairs, which undergo further photolysis leading to the [Mn^I(CO)_{5 − m}(S)_m(p-semiquinone)] radical-adducts; m = 0–2. These reactions take place alongside the photodisproportionation of Mn₂(CO)₁₀. It has been confirmed that o-quinones, on the other hand, act as good radical-traps, adding oxidatively to the photogenerated Mn(CO)5₅ radicals directly. The overall pattern of photochemical reactions of Mn₂(CO)₁₀ in the presence of coordinating reducible substrates is briefly discussed.     

Neue Phosphor-verbrückte Übergangsmetallcarbonyl-Komplexe Die Kristallstrukturen von [Re2(CO)7(PtBu)3], [Co4(CO)10(PtBu)2], [Ir4(CO)6(PtBu)6] und [Ni4(CO)10(PiPr)6]

New Phosphorus-bridged Transition Metal Carbonyl Complexes. The Crystal Structures of [Re₂(CO)₇(P^tBu)₃], [Co₄(CO)₁₀(P^tBu)₂], [Ir₄(CO)₆(P^tBu)₆], and [Ni₄(CO)₁₀(PⁱPr)₆], (P^tBu)₃ reacts with [Mn₂(CO)₁₀], [Re₂(CO)₁₀], [Co₂(CO)₈] and [Ir₄(CO)₁₂] to form the multinuclear complexes [M₂(CO)₇(P^tBu)₃] (M = Re ( 1 ), Mn ( 5 )), [Co₄(CO)₁₀(P^tBu)₂] ( 2 ) and [Ir₄(CO)₆(P^tBu)₆] ( 3 ). The reaction of (PⁱPr)₃ with [Ni(CO)₄] leads to the tetranuclear cluster [Ni₄(CO)₁₀(PⁱPr)₆] ( 4 ). The complex structures were obtained by X-ray single crystal structure analysis: ( 1 : space group P1 (Nr. 2), Z = 2, a = 917.8(3) pm, b = 926.4(3) pm, c = 1 705.6(7) pm, α = 79.75(3)°, β = 85.21(3)°, γ = 66.33(2)°; 2 : space group C2/c (Nr. 15), Z = 4, a = 1 347.7(6) pm, b = 1 032.0(3) pm, c = 1 935.6(8) pm, β = 105.67(2)°; 3 : space group P1 (Nr. 2), Z = 4, a = 1 096.7(4)pm, b = 1 889.8(10)pm, c = 2 485.1(12) pm, α = 75.79(3)°, β = 84.29(3)°, γ = 74.96(3)°; 4 : space group P2₁/c (Nr. 14), Z = 4, a = 2 002.8(5) pm, b = 1 137.2(8) pm, c = 1 872.5(5) pm, β = 95.52(2)°).     

Photochemistry of Mn2(CO)10

Flash photolysis studies on Mn₂(CO)₁₀ in cyclohexane and THF show that the dominant photochemistry involves photolytic formation of 2 Mn(CO)₅ followed by recombination at rates near the diffusion-controlled limit. A second, relatively, long-lived intermediate is also observed and earlier observations of photodecomposition and photodisproportionation can be accounted for in terms of secondary photolysis of this intermediate. For the equilibrium: Mn₂(CO)₁₀ ? 2 Mn(CO)₅ △H ～ 36 kcal/mol, △S ～ 32 e.u., and K(25°C) ～ 10^?20 where the thermodynamic values have been estimated from kinetic measurements.     

Photoinitiated reactions of (η-C5H5)2MH3 (M  Nb,Ta) with Mn2(CO)10: structure of (η-C5H5)2(CO)Ta(μ-H)Mn2(CO)9

The photoreaction of (η-C₅H₅)₂TaH₃ with Mn₂(CO)₁₀ gives, inter alia, (η-C₅H₅)₂(CO)Ta(μ-H)Mn₂(CO)₉, whose crystal structure reveals an open, bent trimetallic framework. Preliminary mechanistic studies show that this and the analogous niobium reaction proceed via a complex sequence of thermal steps following photoinitiation.     

The effect of pressure on electronic excitations in Mn2(CO)10 and Re2(CO)10

The shift with pressure has been measured for the σ → σ* excitations for crystalline Mn₂(CO)₁₀ and Re₂(CO)₁₀ to 120 kbar. The results are interpreted in terms of the relative importance of the effect of compression on stabilization of the bonding vis-a-vis the antibonding orbitals, and the importance of the van der Waals interaction with the surroundings. The π → σ* excitation in Mn₂(CO)₁₀ and the σ → π* excitation in Re₂(CO)₁₀ are briefly discussed.     

Binuclear metal carbonyl dab complexes : II. The syntheses and coordination properties of Mn(CO)5M′(CO)3DAB (M′ = Mn,Re; DAB = 1,4-diazabutadiene)

Mn(CO)₅M′(CO)₃DAB complexes (M′ = Mn, Re; DAB = R₁N=C(R₂)-C(R′₂)=NR₁) can be easily obtained from the reaction between Mn(CO)₅^? and M′(CO)₃X(DAB) (M′ = Mn, Re; X = Cl, Br, I). The complexes are formed by a nucleophilic mechanism, while a redistribution is responsible for the formation of a small amount of Mn₂(CO)₁₀.A diastereotopic effect can be observed in the ¹H and ¹³C NMR spectra of complexes having isopropyl groups attached to the DAB ligand skeleton. A comparison is made with mononuclear complexes of the same symmetry, and the chemical shift differences for the methyl groups strongly depend on the substituent on the central metal responsible for the asymmetry.The low temperature enhancement of the σ → σ^★ transition localised on the metal—metal bond, which is normally observed for this type of compounds, was not observed for the Mn(CO)₅M′(CO)₃(DAB) complexes. The metal—metal bond can be activated by irradiating at the wave lengths associated with the CT transitions between the metal and the DAB ligand. Metal—metal bond cleavage occurs and Mn₂(CO)₁₀ is formed.     

Metal dimers as catalysts : III. The reaction between Fe(CO)5, and group V donor ligands in the presence of [(η5-C5H4R)Fe(CO)222]2 (R  H,Me) and [(η5-C5Me5)Fe(CO)2]2 as catalyst

The reaction between Fe(CO)₅, and group V donor ligands L, (L  PPh₃, AsPh₃, SbPh₃, PMePh₂, PMe₂Ph, Asme₂Ph, P(C₆H₁₁)₃, P(n-Bu)₃, P(i-Bu)₃, P(OPh)₃, P(OEt)₃, P(OMe)₃) in the presence of [(η⁵-C₅Me₅Fe(CO)₂]₂ (R  H, Me) or [(η⁵-C₅Me₅)Fe(CO)₂]₂ as catalyst in refluxing toluene, rapidly gives the complexes Fe(CO)₄L in yields > 85%. The reaction rate is essentially independent of the nature of L for [(η₅-C₅Me₅)Fe(CO)₂]₂ as catalyst. For the other catalysts, the rate is influenced predominantly by the steric properties of L. These results are interpreted in terms of the interaction between the catalyst and the ligand L to give derivatives of the type (η⁵-C₅H₄R)₂Fe₂,(CO)₃,(L). These derivatives were also found to catalyse the reaction between Fe(CO)₅, and L. The complexes [(η-C₅H₄R)Fe(CO)₂]₂ (R  H, Me) and [(η⁵-C₅Me₅)Fe(CO)₂]₂ also catalyse the reaction between Mn₂(CO)₁₀ and PPh₃ to give Mn₂(CO)₈- PPh₃)₂ in > 80% yield.     

Formation of the Salt‐like Complexes [Co{S2CC(PPh3)2}3][Co(CO)4]3 and [(CO)4Mn{S2CC(PPh3)2}][Mn(CO)5] from the Reaction of the Related Carbonyl Compounds with S2CC(PPh3)2

The betain‐like compound S₂CC(PPh₃)₂ ( 1 ), which is obtained from CS₂ and the double ylide C(PPh₃)₂, reacts with [Co₂(CO)₈] and [Mn₂(CO)₁₀] in THF to afford the salt‐like complexes [Co{S₂CC(PPh₃)₂}₃][Co(CO)₄]₃ ( 2 ) and [(CO)₄Mn{S₂CC(PPh₃)₂}][Mn(CO)₅] ( 3 ), respectively, in good yields. At both d⁶ cations 1 acts as a chelating ligand. Disproportionation reactions from formal Co⁰ into Co^III and Co^?I and from Mn⁰ into Mn^I and Mn^?I occurred with the removal of four or one carbonyl groups, respectively. The crystal structures of 2· 5.5THF and 3· 2THF are reported, which show a shortening of the C–C bond in the ligand upon complex formation. The compounds are further characterized by ³¹P NMR and IR spectroscopy.     

Zweikernkomplexe des Typs Mn2(CO)8E(CF3)2E′R (E = P,As; E′ = S,Se, Te): Darstellung und Struktur

Perfluoromethyl Element Ligands. XLII Binuclear Complexes of the Type Mn₂(CO)₈E(CF₃)₂E′R (E = P, As; E′ = S, Se, Te): Synthesis and Structure Complexes of the type Mn₂(CO)₈E(CF₃)₂E′R, in which the groups E(CF₃)₂ and E′R act as bridging ligands, are prepared either by direct reactions of Mn₂(CO)₁₀ with (F₃C)₂EE′R (E = P, As; E′ = S, Se, Te) or by substitution of the iodine bridge in the representatives Mn₂(CO)₈ E(CF₃)₂I (E = P, As) with mercury compounds Hg(E′R)₂. As a rule the binuclear systems contain four‐membered heterocycles (Mn₂EE′). However, the reactions of Mn₂(CO)₁₀ with (F₃C)₂PE′P(CF₃)₂ (E′ = S, Se) yield five‐membered rings [Mn₂P(E′P)]. The compounds have been characterized by spectroscopic (NMR, IR, MS), analytic (C, H) and X‐ray diffraction investigations. The pyramidal Mn₂E′R fragment shows dynamic behaviour in solution via inversion between two identical structures.     

Deprotonierung von Mn2(μ-H)(μ-PR2)(CO)8 (R=Ph,Cy) zur Synthese von Heteronuklearen Mangan—Gold Clustern mit Mn2Aun-Kernen (n = 1 – 3)

Deprotonation of Mn₂(μ-H)(μ-PR₂)(CO)₈ (R = Ph Cy) for Synthesis of Heteronuclear Manganese-Gold Clusters with Mn₂Au_n Cores (n = 1–3) The dimanganese complexes Mn₂(μ-H)(μ-PR₂)(CO)₈ (R = Ph, Cy) have been deprotonated with 1,8-diazabicyclo[5.4.0]undec-7-en (DBU) in tetrahydrofuran solution at 20^°C to give the anions [Mn₂(μ-PR₂)(CO)₈]^?, which were isolated as tetraethylammonium salts. Both dimanganese complexes and the related anions were measured by cyclic voltammetry. The treatment of the aforementioned dimanganese complexes in thf solution with Lir' (R =Me, Ph) and subsequently with PPh₃AuCl gave at 20^°C three types of products: Mn₂(μ-PR₂(CO)₈(AuPPh₃),Mn₂(μ-PR₂)(μ-C(R′)O)(CO)₆-(AuPPh₃)₂ and Mn₂(μ-PR₂)(CO)₆(AuPPh₃)₃. The newly prepared substances were characterized by means of IR-, UV/VIS, ³¹P NMR data. The results of single X-ray analyses showed for the three-membered metal ring compound Mn₂(μ-PPh₂)(CO)₈(AuPPh₃) an uni-fold bridged σ(Mn? Mn) bond length of 306.7(3) pm, the metallatetrahedron complex Mn₂(μ-PPh₃)(μ-C(Ph)O(CO)₆(AuPPh₃)₂ a twofold bridged σ(Mn? Mn) bond length of 300.6(4) pm and the trigonal-bipyramidal cluster Mn₂(μ-Pph₂)(CO)₆(AuPPh₃)₃ an uni-fold bridged π(Mn? Mn) bond length of 274.7(3) pm. The Mn? Au bonds of these substances are accompanyied by semi-bridging CO ligands which are signified through short Au…C contact lengths in the range of 251 to 270 pm. In the substance with the Mn₂Au₂ metallatetrahedron core exists, additionally, such a contact with the acylic C atom of C(Ph)O bridging group of 263.4(18) pm. Such contact lengths were compared for corresponding dimanganese and dirhenium complexes.     

Einkristall-Röntgenstrukturanalysen an Verbindungen mit kovalenter Metall–Metall-Bindung. IV. Die Molekül- und KristallStruktur von Mn2(CO)8[μ-Sn(Br)Mn(CO)5]2

Single Crystal X-Ray Analysis of Compounds with Covalent Metal—Metal Bonds. IV. Molecular and Crystal Structure of Mn₂(CO)₈[μ-Sn(Br) Mn(CO)₅]₂ Mn₂(CO)₈[μ-Sn(Br)Mn(CO)₅]₂ crystallizes in the monoclinic crystal system (a = 881.7 pm; b = 1237.6 pm; c = 1551.1 pm und β = 63.54°) in the space group P2₁/n with two formula units in the cell. The structure was solved by means of 2601 symmetrically independent reflections using the heavy atom method. The central molecule fragment of Mn₂(CO)₈ · [μ-Sn(Br)Mn(CO)₅]₂ consists of a planar Mn₂Sn₂ rhombus with a Mn? Mn-bond (Mn? Mn = 308.6(1) pm) across the metal ring. Besides the bonds to both Mn ring atoms each Sn(IV) atom has a terminal bond to a Br and Mn(CO)₅ ligand, building up a distorted tetrahedron around the Sn(IV) atom. The terminal ligands in Mn₂(CO)₈[μ-Sn(Br)Mn(CO)₅]₂ are in transposition with respect to the ring. The mean values for the remaining bond distances are: Sn? Mn = 263.0(1) pm; Sn? Br = 255.4(1) pm; Mn? C = 184.4(6) pm; C? O = 113.3(7) pm. A comparison of the Sn₂Mn₂ ring with similar metal rings has been given.     

Structure of Mn2(CO)10 and Mn2(CO)9: Insights from ab initio calculations

Optimization of the Mn–Mn distance in Mn₂(CO)₁₀ with various basis sets of at least doublezeta quality results in Mn–Mn bond lengths in the range of 3.07–3.15 Å, 0.2–0.25 Å longer than the experimental value of 2.895 Å. Incrementing the basis set with diffuse p functions (exponent 0.0332) on the carbon atoms improves the calculated bond length to a value of 2.876 Å at the CI level, as a consequence of a charge transfer between each Mn atom and the equatorial carbonyls of the other Mn atom. For Mn₂(CO)₉ four structures have been studied at the SCF and CI levels with assumed geometries. The structure with a symmetric bridging carbonyl turns to be much higher in energy at the SCF level. The two structures which are purely metal–metal bonded [corresponding to the departure of an axial or equatorial carbonyl from Mn₂(CO)₁₀] are nearly degenerate in energy and more stable than the structure with a semibridging carbonyl by 5 kcal/mol at the SCF level and 10–11 kcal/mol at the CI level (seemingly at variance with the conclusions of matrix experiments that favor the semibridging structure).     

Photoinduced synthesis of the mixed metal “manganese rhenium cubane” [Mn3Re(CO)12(SC6H5)4]

The photoinduced synthesis and spectroscopic properties of the new mixed metal compound [Mn₃Re(CO)₁₂(SC₆H₅)₄] by UV irradiation of a mixture of Mn₂(CO)₁₀, Re₂(CO)₁₀ with S₂(C₆H₅)₂ is described. No mixed sulphur/selenium compounds [M₄(CO)₁₂S_nSe_4?n(C₆H₅)₄] (M = Mn or Re, n = 1–3) could be obtained by analogous photoreactions.     

Synthese und Struktur der Phosphor-verbrückten Übergangsmetallkomplexe [Fe2(CO)6(PR)6] (R = tBu,iPr), [Fe2(CO)4(PiPr)6], [Fe2(CO)3Cl2(PtBu)5], [Co4(CO)10(PiPr)3], [Ni5(CO)10(PiPr)6] und [Ir4(C8H12)4Cl2(PPh)4]

Synthesis and Structure of the Phosphorus-bridged Transition Metal Complexes [Fe₂(CO)₆(PR)₆] (R = ^tBu, ⁱPr), [Fe₂(CO)₄(PⁱPr)₆], [Fe₂(CO)₃Cl₂(P^tBu)₅], [Co₄(CO)₁₀(PⁱPr)₃], [Ni₅(CO)₁₀(PⁱPr)₆], and [Ir₄(C₈H₁₂)₄Cl₂(PPh)₄] (P^tBu)₃ and (PⁱPr)₃ react with [Fe₂(CO)₉] to form the dinuclear complexes [Fe₂(CO)₆(PR)₆] (R = ^tBu: 1 ; ⁱPr: 2 ). 2 is also formed besides [Fe₂(CO)₄(PⁱPr)₆] ( 3 ) in the reaction of [Fe(CO)₅] with (PⁱPr)₃. When PⁱPr(P^tBu)₂ and PⁱPrCl₂ are allowed to react with [Fe₂(CO)₉] it is possible to isolate [Fe₂(CO)₃Cl₂(P^tBu)₅] ( 4 ). The reactions of (PⁱPr)₃ with [Co₂(CO)₈] and [Ni(CO)₄] lead to the tetra- and pentanuclear clusters [Co₄(CO)₁₀(PⁱPr)₃] ( 5 ), [Ni₄(CO)₁₀(PⁱPr)₆] [2] and [Ni₅(CO)₁₀(PⁱPr)₆] ( 6 ). Finally the reaction of [Ir(C₈H₁₂)Cl]₂ with K₂(PPh)₄ leads to the complex [Ir₄(C₈H₁₂)₄Cl₂(PPh)₄] ( 7 ). The structures of 1–7 were obtained by X-ray single crystal structure analysis (1: space group P2₁/c (Nr. 14), Z = 8, a = 1 758.8(16) pm, b = 3 625.6(18) pm, c = 1 202.7(7) pm, β = 90.07(3)°; 2 : space group P1 (Nr. 2), Z = 1, a = 880.0(2) pm, b = 932.3(3) pm, c = 1 073.7(2) pm, α = 79.07(2)°, β = 86.93(2)°, γ = 72.23(2)°; 3 : space group Pbca (Nr. 61), Z = 8, a = 952.6(8) pm, b = 1 787.6(12) pm, c = 3 697.2(30) pm; 4 : space group P2₁/n (Nr. 14), Z = 4, a = 968.0(4) pm, b = 3 362.5(15) pm, c = 1 051.6(3) pm, β = 109.71(2)°; 5 : space group P2₁/n (Nr. 14), Z = 4, a = 1 040.7(5) pm, b = 1 686.0(5) pm, c = 1 567.7(9) pm, β = 93.88(4)°; 6 : space group Pbca (Nr. 61), Z = 8, a = 1 904.1(8) pm, b = 1 959.9(8) pm, c = 2 309.7(9) pm. 7 : space group P1 (Nr. 2), Z = 2, a = 1 374.4(7) pm, b = 1 476.0(8) pm, c = 1 653.2(9) pm, α = 83.87(4)°, β = 88.76(4)°, γ = 88.28(4)°).