Eberhard Matern

A new synthetic entry to phosphinophosphinidene complexes. Synthesis and structural characterisation of the first side-on bonded and the first terminally bonded phosphinophosphinidene zirconium complexes [μ-(1,2∶2-η-tBu2PP){Zr(Cl)Cp2}2] and [{Zr(PPhMe2)Cp2}(η1-P–PtBu2)]

The reactions of lithiated diphosphanes with transition metal chlorides constitute a new general entry to phosphinophosphinidene complexes: the reaction of Cp2ZrCl2(Cp = C5H5) with tBu2P-P(SiMe3)Li (molar ratio approximately 1:1) yields [mu-(1,2:2-eta-tBu2P=P)[Zr(Cl)Cp2]2]; the reaction of Cp2ZrCl2 with tBu2P-P(SiMe3)Li (molar ratio approximately 1:2) and an excess of PPhMe2 in DME yields the first terminally bonded phosphinophosphinidene complex, [[Zr(PPhMe2)Cp2](eta1-P-PtBu2)].

A Conformational Study on Silacyclohexane. Comparison ofab initio (HF, MP2), DFT, and Molecular Mechanics Calculations. Conformational Energy Surface of Silacyclohexane

The structures and relative energies for the basic conformations of silacyclohexane 1 have been calculated using HF, RI-MP2, RI-DFT and MM3 methods. All methods predict the chair form to be the dominant conformation and all of them predict structures which are in good agreement with experimental data. The conformational energy surface of 1 has been calculated using MM3. It is found that there are two symmetric lowest energy pathways for the chair-to-chair inversion. Each of them consists of two sofa-like transition states, two twist forms with C1 symmetry (twist-C1), two boat forms with Si in a gunnel position (C1 symmetry), and one twist form with C2 symmetry (twist-C2). All methods calculate the relative energy to increase in the order chair < twist-C2 < twist-C1 < boat. At the MP2 level of theory and using TZVP and TZVPP (Si atoms) basis sets the relative energies are calculated to be 3.76, 4.80, and 5.47 kcal mol–1 for the twist-C2, twist-C1, and boat conformations, respectively. The energy barrier from the chair to the twisted conformations of 1 is found to be 6.6 and 5.7 kcal mol–1 from MM3 and RI-DFT calculations, respectively. The boat form with Si at the prow (Cs symmetry) does not correspond to a local minimum nor a saddle point on the MM3 energy surface, whereas a RI-DFT optimization under Cs symmetry constraint resulted in a local minimum. In both cases its energy is above that of the chair-to-twist-C1 transition state, however, and it is clearly not a part of the chair-to-chair inversion. Konformationen siliciumhaltiger Ringe. II Eine Konformationsuntersuchung des Silacyclohexans durch Vergleich von ab initio (HF, MP2), DFT- und Molekulmechanik-Rechnungen. Die Konformationshyperflache von Silacyclohexan. Strukturen und relative Energien der Grundkonformationen des Silacyclohexans 1 wurden nach HF-, RI-MP2-, RI-DFT- und MM3-Verfahren berechnet. Alle Verfahren fuhren zur Sesselform als vorherrschender Konformation, und alle berechneten Strukturen stimmen gut mit der experimentell gefundenen uberein. Die Konformationshyperflache von 1 wurde mit MM3 berechnet. Dabei wurden zwei symmetrische Wege niedrigster Energie fur die Inversion Sessel-Sessel gefunden. Beide enthalten zwei Sofa-artige Ubergangszustande, zwei Twistformen mit C1-Symmetrie (Twist-C1), zwei Bootformen mit Si an der Seite (C1-Symmetrie) und eine Twistform mit C2-Symmetrie (Twist-C2). Alle Methoden berechnen die relativen Energien der Konformationen in der Reihenfolge: Sessel < Twist-C2 < Twist-C1 < Boot. Berechnungen auf dem RI-MP2 Level der Theorie unter Verwendung der Basissatze TZVP und TZVPP (Si Atome) fuhren zu relativen Energiewerten von 3.76, 4.80 bzw. 5.47 kcal mol–1 fur die Twist-C2, Twist-C bzw. Boot-Konformationen. Die Energiebarriere vom Sessel zu den Twist-Konformationen von 1 betragt 6.6 bzw. 5.7 kcal mol–1 nach MM3- bzw. RI-DFT-Rechnungen. Auf der MM3-Energie-Hyperflache entspricht das Boot mit Si am Bug (Cs-Symmetrie) weder einem lokalen Minimum noch einem Sattelpunkt; jedoch fuhrt eine RI-DFT-Optimierung mit auf Cs festgelegter Symmetrie zu einem lokalen Minimum. Allerdings liegt die Energie in beiden Fallen uber der fur den Ubergangszustand der Umwandlung des Sessels zu Twist-C1. Deshalb ist das Cs-Boot offensichtlich auch nicht an der Inversion Sessel-Sessel beteiligt.

Syntheses and structures of the first terminal phosphanylphosphido complex of hafnium [Cp2Hf(Cl){η1-(Me3Si)P–P(NEt2)2}] and the first zirconocene-phosphanylphosphinidene dimer [Cp2Zr{μ2-P–P(NEt2)2}2ZrCp2]

Reactions of (Et(2)N)(2)P-P(SiMe(3))Li with [Cp(2)MCl(2)] (M = Zr, Hf) in toluene or pentane yield the related terminal phosphanylphosphido complexes [Cp(2)M(Cl){η(1)-(Me(3)Si)P-P(NEt(2))(2)}]. The solid state structure of [Cp(2)Hf(Cl){η(1)-(Me(3)Si)P-P(NEt(2))(2)}] was established by single crystal X-ray diffraction. The reaction of (Et(2)N)(2)P-P(SiMe(3))Li with [Cp(2)ZrCl(2)] in THF or DME solutions leads to the formation of deep red crystals of the first neutral diamagnetic zirconocene-phosphanylphosphinidene dimer [Cp(2)Zr{μ(2)-P-P(NEt(2))(2)}(2)ZrCp(2)]. The molecular structure of this compound was confirmed by X-ray diffraction. The reactions of (R(2)N)(2)P-P(SiMe(3))Li with [CpZrCl(3)] yield the related tetraphosphetanes R(2)NP(μ(2)-PSiMe(3))(2)PNR(2), which apparently are formed as a result of a transfer of NR(2) groups from a P atom to the Zr atom.

Zum Einfluß der PR3-Liganden auf Bildung und Eigenschaften der Phosphinophosphiniden-Komplexe [{η2-tBu2P–P}Pt(PR3)2] und [{η2-tBu2P1–P2}Pt(P3R3)(P4R′3)]

Die aus (R3P)2PtCl2 und C2H4 gebildeten Verbindungen [{η2-C2H4}Pt(PR3)2] (PR3 = PMe3, PEt3, PPhEt2, PPh2Et, PPh2Me, PPh2iPr, PPh2tBu und P(p-Tol)3) reagieren mit tBu2P–P=PMetBu2 zu den Phosphinophosphiniden-Komplexen [{η2-tBu2P–P}Pt(PMe3)2], [{η2-tBu2P–P}Pt(PEt3)2], [{η2-tBu2P–P}Pt(PPhEt2)2], [{η2-tBu2P–P}Pt(PPh2Et)2], [{η2-tBu2P–P}Pt(PPh2Me)2], [{η2-tBu2P–P}Pt(PPh2iPr], [{η2-tBu2P–P}Pt(PPh2tBu)2] und [{η2-tBu2P–P}Pt(P(p-Tol)3)2]. [{η2-tBu2P–P}Pt(PPh3)2] reagiert mit PMe3 und PEt3 sowie mit tBu2PMe, PiPr3 und P(c-Hex)3 unter Substitution eines PPh3-Liganden zu den Verbindungen [{η2-tBu2P1–P2}Pt(P3Me3)(P4Ph3)], [{η2-tBu2P1–P2}Pt(P3Ph3)(P4Me3)], [{η2-tBu2P1–P2}Pt(P3Et3)(P4Ph3)], [{η2-tBu2P1–P2}Pt(P3MetBu2)(P4Ph3)], [{η2-tBu2P1–P2}Pt(P3iPr3)(P4Ph3)] und [{η2-tBu2P1–P2}Pt(P3(c-Hex)3)(P4Ph3)]. [{η2-tBu2P–P}Pt(P(p-Tol)3)2] bildet mit tBu2PMe das [{η2-tBu2P1–P2}Pt(P3MetBu2)(P4(p-Tol)3)]. Es werden die NMR-Daten der Verbindungen angegeben und im Hinblick auf den Einflus der PR3-Liganden diskutiert.

Syntheses, structures, and comprehensive NMR spectroscopic investigations of hetero-chalcogenidometallates: the right mix toward multinary complexes.

Aqueous solutions of ternary ortho-chalcogenidostannate anions [SnE(1)(4-x)E(2)(x)](4-) (E(1), E(2) = S, Se, Te) have been generated following different routes that all lead to equilibria of all possible permutations of binary and ternary anions. This has been rationalized by means of NMR studies that can be explained by calculations using density functional theory (DFT) methods. Thus, if one reacts such solutions with transition-metal ions, quaternary M/Sn/E(1)/E(2) anions are obtained, which exhibit coordination by different ternary chalcogenidostannate ligands. The electronic excitation energies of the corresponding alkali metal salts lie between the E(g) values of compounds containing either M/Sn/E(1) or M/Sn/E(2) anions. In this way, we provide a simple approach toward a library of semiconductor compounds with finely-tuned optoelectronic properties.

Conformations of silicon-containing rings. Part 3. Relative conformational energies of alkylated 1,3,5-trisilacyclohexanes as calculated from quantum chemical and molecular mechanics methods☆

Abstract The relative energies of the basic conformations for five series of Si-alkylated derivatives of 1,3,5-trisilacyclohexane 1 with methyl, ethyl, i -propyl and t -butyl alkyl groups have been calculated using quantum chemical (QC) methods (HF and RI-DFT) and the MM3 force field. The results were compared to those from previous NMR investigations. It was found that the QC methods predict for all 1-mono-, cis -1,3-di and cis–cis -1,3,5-tri-alkylated 1 the chair(eq) to be the lowest energy conformation. The QC methods also predict a preference for twisted conformation in the cases of trans -1,3-di- and cis–trans -1,3,5-tri- t -butylated 1 . The QC results confirm earlier predictions from the NMR data. In contrast, MM3 fails to calculate relative conformational energies properly. The reason for its failure is discussed.

Bildung und Strukturen von [{η2‐tBu2P–P=P–PtBu2}Pt(PR3)2]

tBu2P–P=P(Me)tBu2 reagiert sowohl mit [{η2-C2H4}Pt(PR3)2] als auch mit [{η2-tBu2P–P}Pt(PR3)2] unter Bildung von [{η2-tBu2P–P=P–PtBu2}Pt(PR3)2]; PR3 = PMe33 a, PEtPh23 b, 1/2 dppe 3 c, PPh33 d, P(p-Tol)33 e. Die Verbindungen sind uber 1H- und 31P-NMR-Untersuchungen belegt. Von 3 b und 3 d liegen Einkristallstrukturanalysen vor. 3 b kristallisiert triklin, P1 (Nr. 2) mit a = 1212,58(7), b = 1430,74(8), c = 1629,34(11) pm, α = 77,321(6), β = 70,469(5), γ = 87,312(6)°. 3 d kristallisiert triklin, P1 (Nr. 2) mit a = 1122,60(9), b = 1355,88(11), c = 2025,11(14) pm, α = 83,824(9), β = 82,498(9), γ = 67,214(8)°. Coordination Chemistry of P-rich Phosphanes and Silylphosphanes. XVIII. Syntheses and Structures of [{η2-tBu2P–P=P–PtBu2}Pt(PR3)2] tBu2P–P=P(Me)tBu2 reacts with [{η2-C2H4} · Pt(PR3)2] as well as with [{η2-tBu2P–P}Pt(PR3)2] yielding [{η2-tBu2P–P=P–PtBu2}Pt(PR3)2]; PR3 = PMe33 a, PEtPh23 b, 1/2 dppe 3 c, PPh33 d, P(p-Tol)33 e. All compounds are characterized by 1H and 31P NMR spectra, for 3 b and 3 d also crystal structure determinations were performed. 3 b crystallizes in the triclinic space group P1 (No. 2) with a = 1212.58(7), b = 1430.74(8), c = 1629.34(11) pm, α = 77.321(6), β = 70.469(5), γ = 87.312(6)°. 3 d crystallizes in the triclinic space group P1 (No. 2) with a = 1122.60(9), b = 1355.88(11), c = 2025.11(14) pm, α = 83.824(9), β = 82.498(9), γ = 67.214(8)°.

[Co4P2(PtBu2)2(CO)8] und [{Co(CO)3}2P4tBu4] aus Co2(CO)8 undtBu2P-P=P(Me)tBu2

Co2(CO)8 bildet mit tBu2P–P=P(Me)tBu2 die Verbindungen [Co4P2(PtBu2)2(CO)8] (1) und [{η2-tBu2P=P–P=PtBu2}{Co(CO)3}2] (2 a) cis, (2 b) trans. In Verbindung 1 bilden vier Co- und zwei P-Atome eine tetragonale Bipyramide, in der je zwei benachbarte Co-Atome uber eine tBu2P-Gruppe μ2-verbruckt sind. An jedes Co-Atom sind noch zwei CO-Gruppen gebunden. In den Verbindungen 2 a und 2 b sind die Co(CO)3-Gruppen an die endstandigen P2-Einheiten jeweils η2-koordiniert, wobei sich die cis- und trans-Anordnungen 2 a und 2 b ausbilden. 1 kristallisiert orthorhombisch in Pnnm (Nr. 58) mit a = 879,41(5), b = 1199,11(8), c = 1773,65(11) pm. 2 a kristallisiert monoklin in P21/n (Nr. 14) mit a = 875,97(5), b = 1625,36(11), c = 2117,86(12) pm, β = 91,714(7)°. 2 b kristallisiert triklin in P 1 (Nr. 2) mit a = 812,00(10), b = 843,40(10), c = 1179,3(2) pm, α = 100,92(2)°, β = 102,31(2)°, γ = 102,25(2)°. Coordination Chemistry of P-rich Phosphanes and Silylphosphanes. XIX. [Co4P2(PtBu2)2(CO)8] and [{Co(CO)3}2P4tBu4] from Co2(CO)8 and tBu2P–P=P(Me)tBu2 Co2(CO)8 reacts with tBu2P–P=P(Me)tBu2 yielding the compounds [Co4P2(PtBu2)2(CO)8] (1) and [{η2tBu2P=P–P=PtBu2}{Co(CO)3}2] (2 a) cis, (2 b) trans. In 1, four Co and two P atoms form a tetragonal bipyramid, in which two adjacent Co atoms are μ2-bridged by tBu2P groups. Additionally, two CO groups are linked to each Co atom. In 2 a and 2 b, each of the Co(CO)3 units is η2-coordinated to the terminal P2 units resulting in the cis- and trans-configurations 2 a and 2 b. 1 crystallizes in the orthorhombic space group Pnnm (No. 58) with a = 879,41(5), b = 1199,11(8), c = 1773,65(11) pm. 2 a crystallizes in the monoclinic space group P21/n (No. 14) with a = 875,97(5), b = 1625,36(11), c = 2117,86(12) pm, β = 91,714(7)°. 2 b crystallizes in the triclinic space group P 1 (No. 2) with a = 812,00(10), b = 843,40(10), c = 1179,3(2) pm, α = 100,92(2)°, β = 102,31(2)°, γ = 102,25(2)°.

(Di-tert-butyl­phosphan­yl)bis­(diphenyl­phosphan­yl)phosphane

The title phosphane, C32H38P4 or (Ph2P)2P(PtBu2), has a P atom that is linked to another three P atoms in a pyramidal configuration; the P—P distances in the range 2.2231 (7)–2.2446 (7) Å indicate that the P—P bonds are single bonds.

Die Reaktion vontBu2P-P=P(Me)tBu2 mit [Fe2(CO)9] und [(η2-C8H14)2Fe(CO)3]

tBu2PP:P(Me)tBu2 reacts with [Fe2(CO)9] to give [m-(1,2,3:4-h-tBu2PPPPtBu2){Fe(CO)3}{Fe(CO)4}] (I) and [trans-(tBu2MeP)2Fe(CO)3] (II). With [(h2-C8H14)2Fe(CO)3] in addn. to [m(1,2,3:4-h-tBu2PPPPtBu2){Fe(CO)2PMetBu2}{Fe(CO)4}] and II also [(m-PtBu2){m-P-Fe(CO)3PMetBu2}{Fe(CO)3}2(Fe-Fe)] (III) is formed. Compd. I crystallizes in the monoclinic space group P21/c with a = 875.0(2), b = 1073.2(2), c = 3162.6(6) pm, b = 94.64(3) Deg. Compd. II crystallizes in the monoclinic space group P21/c with a = 1643.4(7), b = 1240.29(6), c = 2667.0(5) pm, b = 97.42(2) Deg. Compd. III crystallizes in the monoclinic space group P21/n with a = 1407.5(5), b = 1649.7(5), c = 1557.9(16) pm, b = 112.87(2) Deg. [on SciFinder (R)]