The crystal structure of the title compound, [ t Bu 2 P(S)N i Pr] 2 Ni or [Ni(C 11 H 25 NPS) 2 ], shows a dihedral angle of 82.27 (6)° between the two Ni/S/N planes and thus a distorted tetrahedral arrangement of the NiN 2 S 2 chromophore. The structure is in accordance with the observed paramagnetism and is contrasted with the oxo analogue, which is planar but also paramagnetic.

After a brief review of previous work the results of the metathesis reaction between Ni(dme)Br-2 and R(2)P(O)NR'Li [R = tBu, iPr, Ph; R' = Et, Pr, iPr, (+/-)-sBu, tBu, tPen, Cy, Ph, (-)-alpha-methylbenzyl = Mb, 1-adamantyl = Ad] are reported. Complex formation occurred only with lithiated amides of tertbutylphosphinic acid, and bischelates [tBu(2)P(O)NR']Ni-2 were obtained when R' = sBu, Mb, tPen, Ad (Id-g). With R' = Et, Pr bischelation was incomplete. Vis spectroscopy showed the paramagnetic compounds 1d-f to be planar in the solid state but tetrahedral in solution. Ig is tetrahedral in both phases. The planar structure of If was confirmed by X-ray single crystal analysis (monoclinic, space group P2(1)/n). The magnetic moments mu(eff) of 1d, e, g are ca. 3.2-3.5 mu(B) in both phases and the Curie-Weiss law is obeyed in the range 293-183 K. The same is valid for dissolved If. The mu(eff) values of solid If are, however, strongly temperature-dependent, varying from 1.38 to 0.55 mu(B) (300-90 K). NMR data (P-31, H-1, C-13) are reported. Obviously, a favorable combination of electronic and steric factors of substituents R and R' produces with ligands [R(2)P(O)NR'](-) the donor quality necessary for bischelation as well as the singular field strength required for the formation of planar paramagnetic species. As the combination of paramagnetism and planarity is bound to the solid state, lattice energy effects may be finally decisive for this unique constellation of tetracoordinated Ni-II complexes.

The structure of the gaseous long-lived radical cation generated upon electron ionization of trimethylphosphine oxide, (CH3)3PO, has been investigated by using ion-molecule reactions in a Fourier transform ion cyclotron resonance mass spectrometer. A radical cation with the connectivity of trimethylphosphine oxide is expected to react by facile electron transfer with triethylamine, pyridine and dimethyl disulfide since all these reactions are highly exothermic. However, no electron transfer reactions were observed. Instead, the radical cation transfers a proton to triethylamine and to pyridine, i.e., acts as a Brønsted acid. Further, the radical cation abstracts CH3S from dimethyl disulfide and hence demonstrates behavior characteristic of a distonic ion with a carbon radical center. This reactivity is unprecedented for a radical cation such as (CH3)3P+-O with the odd spin located at an oxygen atom. These experimental results indicate that the initially generated radical cation (CH3)3P+-O undergoes unimolecular isomerization to (CH3)2P+(OH)CH2 within a millisecond time frame. Ab initio molecular orbital calculations carried out at the unrestricted second-order Møller-Plesset (UMP2/6-31G** + ZPVE) level of theory support this conclusion by predicting that (CH3)2P+(OH)CH2 lies 23 kcal mol−1 lower in energy than (CH3)3P+-O. The energy barrier for unimolecular [1,3]-hydrogen atom migration in (CH3)3P+-O is estimated to be 24 kcal mol−1. This study demonstrates that the PO moiety provides a very strong driving force for hydrogen shifts in phosphorus containing radical cations.

Crystal structure analysis of (CO)(5)CrPH2COOH (a = 1338.2, b = 622.6, c = 1161.5 pm, beta = 96,77 degrees, P2(1)/c, Z = 4, R = 0.0330) has shown the complex to be dimerized via hydrogen-bonds of the COOH group. Geometrical parameters of the hypothetical free ligand [H2PCOOH](2) were calculated using the HF/3-21 G*, HF/6-31 G** and MP2-FU/6-31 G** basis sets. Bond lengths and bond angles of the calculated free ligand are similar to those derived from the crystal structure analysis of the coordinated ligand and are not significantly influenced by coordination and/or intermolecular interactions.

Crystal structure analysis of (CO)5CrPH2COOH (a = 1338.2, b = 622.6, c = 1161.5 pm, β = 96,77°, P21/c, Z = 4, R = 0.0330) has shown the complex to be dimerized via hydrogen-bonds of the COOH group. Geometrical parameters of the hypothetical free ligand [H2PCOOH]2 were calculated using the HF/3-21 G*, HF/6-31G** and MP2-FU/6-31 G** basis sets. Bond lengths and bond angles of the calculated free ligand are similar to those derived from the crystal structure analysis of the coordinated ligand and are not significantly influenced by coordination and/or intermolecular interactions.

The diamagnetic tetranuclear cluster complexes Mo3CuS4I(R2PS2)4•C5H5N 2 (a: R=Et, b: R=Pr) are obtained by reaction of Mo3S4L4 (L = R2PS2-) 1 with CuI and pyridine. Each Mo atom of the cubane-type Mo3CuS4 core is chelated by L. Two of the Mo atoms are bridged by the fourth L, while a pyridine ligand completes the coordination sphere of the third Mo atom, and iodine is bonded to the Cu atom. Magnetic, NMR- and MS-spectroscopic data are given. 2b crystallizes in the monoclinic space group P21/n with Z = 4 and lattice parameters a = 21,164(7), b = 10,653(3), c = 25,455(8)Å, and β = 106,25(3)°.

The diamagnetic tetranuclear cluster complexes Mo 3 CuS 4 I(R 2 PS 2 ) 4 .C 5 H 5 N 2 (a:R=Et, b:R=Pr) are obtained by reaction of Mo 3 S 4 L 4 (L=R 2 PS 2 - ) 1 with CuI and pyridine. Each Mo atom of the cubane-type Mo 3 CuS 4 core is chelated by L. Two of the Mo atoms are bridged by the fourth L, while a pyridine ligand completes the coordination sphere of the third Mo atom, and iodine is bonded to the Cu atom.

The syntheses of tetranuclear complexes Mo,W2S4L6 3 and Mo2Co2S4L2(CO)2(CH3CN)2 4 (L = R2PS2⁻; a: R = Et, b: R = Pr) containing the cubane-type Mo2M2S4 core are reported. While in 4 both Mo atoms are chelated by L, the dithiophosphinato group acts as a chelating and bridging ligand in 3. It is shown that there exist four isomers of 3 which differ not only in the function of L but also in the kind of metals which are chelated and bridged. Magnetic and NMR spectroscopic data are given. The structure of a mixed crystal of the two β-isomers of 3a containing three bridging and three chelating ligands L is reported: orthorhombic space group Pbca, Z = 8, and lattice parameters a = 2186.6(7), b = 2264.0(7), and c = 2386.7(6) pm.

Entgegen bisheriger Erfahrung in der NiII‐Komplexchemie ist Planaritat nicht unbedingt mit Diamagnetismus verbunden. Nach einer Röntgenstrukturanalyse ist das NiII‐Zentrum im Titelkomplex 1 exakt planar koordiniert. Dennoch zeigt 1 im festen und im gelösten Zustand Curie‐Weiss‐Verhalten und hat ein magnetisches Moment, wie man es bei tetraedrischen NiII‐Komplexen findet. magnified image

Durch Neutralisations‐Reionisations‐Massenspektrometrie (NRMS)äß sich die Stammverbindung der Phosphor‐Ylide, Methylenphosphoran CH2PH3, erzeugen und eindeutig charakterisieren. Diese Substanz läß sich zwar nicht „auf Flaschen ziehen”︁, ist aber unter den Bedingungen des NRMS‐Experiments stabil. Ihre Eigenschaften stimmen mit den theoretisch vorhergesagten überein.

Ph 2 PCOONa 2, hergestellt dutch Reaktion von Ph2PNa mit CO2, wird in protischen Medien rasch unter Bildung von Ph2PH and CO2 hydrolysiert. Die Hydrolyse verlauft in Natronlauge sehr viel langsamer and es bilden sich zusätzlich geringe Mengen Ph2P(O)O− und HCOO−, Aus 2 and stöchiometrischen Mengen RI bilden sich tertiäre Phosphine Ph2PR (R[dbnd]Me, Et) während mit überschüssigem MeI das Phosphoniumsalz [Ph2PMe2]I erhalten wird. Ph2PCOOMe, Ph2PCOOSiMe3 bzw. Ph2PCSSNa wurden durch Umsetzung von 2 mit (MeO)2SO2, Me3SiCl bzw. CS2 synthetisiert. Ph2P(O)ONa and Ph2P(S)SNa entstanden bei der Reaktion von 2 mit O2 oder S8 in Benzol. Concerning Sodiumdiphenylphosphinoformiate Ph2PCOONa1. Ph2PCOONa 2, prepared from Ph2PNa and CO2, is readily hydrolyzed in protic media with formation of Ph 2 PH and CO2. Hydrolysis is much slower in NaOH and small quantities of Ph2P(O)O− and HCOO− are additionally formed. Reactions of 2 with RI in stoichiometrical amounts gave tertiary phosphines Ph2PR (R[dbnd]Me, Et) while the phosphonium compound [Ph2PMe2]I resulted from 2 and MeI in excess. Ph2PCOOMe, Ph2PCOOSiMe3 or Ph2PCSSNa were obtained from 2 and (MeO)2SO2, Me3SiCl or CS2. Ph2P(O)ONa and Ph2P(S)SNa were isolated when 2 was reacted with O2 or S8 in benzene. Key Words: Ph2PCOONaHydrolysisEsters Ph2PCOORPh2PCSSNa 31P{1H}-NMR/13C-NMR.

Diamagnetic clusters [Mo3X-μ-(S2)3-μ3(S)(R2PS2)3] 2-4 (2: X = Cl; 3: X = Br; 4: X = I; 2-4: a: R = Et; b: R = Pr; c: R = Bu) are conveniently obtained by reaction of [Mo3S7(R2PS2)3]+(R2PS2)- 1 either with alkyl halides RX or with tetraalkylammonium halides R4NX. Between halogen X and one of the S atoms of each disulfido bridge there exist bonds which seem to be mainly of covalent character. Thus X is incorporated into the cluster core leading to a cubane type structure. [Mo3ClS7(Et2PS2)3] forms orthorhombic crystals with space group Pnma, Z = 4, a = 1931.9(7), b = 1551.2(6), c = 1286.5(4) pm. Isostructural substructures of 3b, 4a and 4b (space group P21) were also studied. All these cluster molecules reveal similar core geometries with distances S—Cl 239.4(4), S—Br 305(1) and S—I 322.5(3) pm much less than the sum of the van der Waals radii. The results of structural and spectroscopic investigations are discussed.

Ein zweifach koordiniertes, dreiwertiges Phosphoratom liegt in den Titelverbindungen 1 (R = CH 3 , C 6 H 5 ) vor, die durch Elektronenstoßionisation der entsprechenden Dithiadiphosphetandisulfide 2 entstehen. Stoßaktivierungs‐ und Neutralisations‐Reionisations‐Massenspektroskopie zeigen, daß dabei die isomeren Dithioxophosphorane 3 zu 1 umlagern. magnified image

Collisional activation (CA) mass spectra and thermochemical data show that the alkene elimination from the dialkyldithiophosphinic acids (I) leads to a mixture of the tautomeric radical cations (II) and (III) containing tri‐ or dicoordinated phosphorus, whereas tetracoordinated phosphorus corresponding to the ionized dithiophosphinic acid H 2 P(S)SH is not observed.

New Results Concerning the “Phosphorus Monosulfide” (PS)xThe orange‐yellow solid of approximate composition (PS)x obtained by dehalogenation of P(S)Br3 with Mg proved to be a mixture of phosphorus sulfides e.g. P4S3, P4S4, P4S5, P4S7, and insoluble polymeric material. It is suggested that the latter contains a network of triply connected P atoms, many of which are substituted by groups. The conclusions are based on the results of analytical, mass‐spectrometric and 31P‐NMR‐spectroscopic findings.