- 1,3,2-Dithiaphospholanes with an annelated 1,2-dicarba-closo- dodecaborane(12) unit: Formation and reactivity
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1,3,2-Dithiaphospholanes were prepared, containing an annelated 1,2-dicarba-closo-dodecaborane(12) unit, bearing halogens (F, Cl, Br, and I), H, NEt2, OEt groups, or organo substituents (R = i-Pr, t-Bu, Cy, 3,5-Me2-C6H3-CH2, Ph) at phosphorus. The t-Bu derivative was structurally characterised as its sulfide. The organo-substituted derivatives escape the ring strain by irreversible (R = t-Bu; X-ray analysis) or reversible dimerisation, by which 10-membered rings are formed. Using 1,1-bis(dichlorophosphino)methane, another dimer containing a 14-membered ring could be isolated and structurally characterised. The preferred conformation of the 1,3,2-dithiaphospholanes depends on the nature of the substituent at phosphorus. For instance, the substituents R = t-Bu, NEt 2 prefer the equatorial position, as indicated by diagnostic NMR data, supported by DFT calculations [B3LYP/6-311+G(d,p) level of theory]. The calculations also predict the tendency for dimerisation, and calculated NMR parameters are in good agreement, in most cases, with experimental data.
- Wrackmeyer, Bernd,Klimkina, Elena V.,Milius, Wolfgang
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p. 5021 - 5043
(2014/04/03)
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- Design and synthesis of phosphonate inhibitors of glutamine synthetase
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Inhibitors 1-4 have been shown previously to undergo enzymatic phosphorylation by glutamine synthetase (GS). Phosphonates 6-9 were designed as chemically stable analogues of these phosphorylated inhibitors, incorporating either a tetrahedral sulfur group
- Farrington,Kumar,Wedler
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p. 2062 - 2067
(2007/10/02)
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- Synthesis and Properties of Open-Chain and Cyclic 1λ3,3λ3-Diphosphaalkanes RR'P-CH2-PR'R
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Disecondary methylenediphosphanes R(X)PCH2P(X)R with their adjustable positive or negative polarity (X = H, Cl), which are useful building blocks for organophosphorus synthesis, were prepared by multi-step substitution of chlorine atoms in methylenebis(di
- Schmidbaur, Hubert,Schnatterer, Stefan
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p. 2832 - 2842
(2007/10/02)
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- LINEARE OLIGOPHOSPHAALKANE XIII.TRIPHOSPHAALKANE MIT DEM P-C-P-C-P-DONORSKELETT; LIGANDEN FUER DEN AUFBAU VON MEHRKERNKOMPLEXEN
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The triphosphaalkane Cl2PCH2PClCH2PCl2 (III) is formed as a by-product in the synthesis of Cl2PCH2PCl2 (II).On treating III with MeMgCl or EtOH (in the presence of a base), the methyl or ethoxy derivative (V or VI) may be obtained in satisfactory yields.With Ni(CO)4 or Fe2(CO)9 V forms trinuclear complexes nM>PMe2CH2PMen>CH2PMe2n> (X, XIII; M = Fe, Ni; n = 4, 3) or binuclear stable six-membered chelate ring systems n>PMe(CH2PMe2)2m> (IX, XIV; M = Fe, Ni; n = 4, 3; m = 3, 2).An excess of Fe2(CO)9 (molar ratio V/Fe2(CO)9 1/5) yields XI with an Fe-Fe bond or the cluster XII, respectively.In both cases V bridges the Fe-Fe bond with a P-C-P donor set.X-ray structural analysis of X (triclinic, space group P1) exhibits a staggered arrangement of the three metal carbonyl fragments bound to the "stretched" P-C-P-C-P skeleton of V (Fe(1)-P(1) 2.236(1), Fe(2)-P(2) 2.226(1), Fe(3)-P(3) 2.231(1) Angstroem, P(1)-C(13)-P(2) 126.7(1), P(2)-C(14)-P(3) 127.6(1) deg).In XI (monoclinic, space group P21/n) one P-C-P donor set together with the two iron atoms Fe(2) and Fe(3) form a stable five-membered Fe2P2C ring (Fe(2)-Fe(3) 2.705(1), Fe(2)-P(2) 2.251(1), Fe(3)-P(3) 2.239(1) Angstroem).The third phosphorus atom P(1) binds an Fe(CO)4 group (Fe(1)-P(1) 2.245(1) Angstroem).The structure of cluster compound XII (monoclinic, space group P21/n) is derived from that of Os3(CO)12.One P-C-P donor set of V replaces two CO groups in equatorial positions, forming a stable Fe2P2C five-membered ring.The remaining donor position of V coordinates with an Fe(CO)4 group.
- Brauer, David J.,Hietkamp, Sibbele,Sommer, Herbert,Stelzer, Othmar,Mueller, Gerhard,et al.
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p. 411 - 434
(2007/10/02)
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- Oligophosphaalkanes, VI. Syntheses and NMR Spectroscopic Characterization of PH-functional Methylene Bridged Diphosphanes R2P-CH2-PRH and HRP-CH2-PRH
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1,3-Diphosphapropane, H2P-CH2-PH2 (1) was synthesized in about 40 percent yield by reduction of Cl2P-CH2-PCl2 with LiAlH4.The mono-, di-, and tri-substituted derivatives RHP-CH2-PH2 (R = iPr, CH2Ph, 3a, b) RHP-CH2-PHR (R = iPr, CH2Ph, tBu, 5a - c), R2P-CH2-PRH (R = Me, iPr, CH2Ph, 10b, 7a, b) are accessible using Cl2P-CH2-PCl2 as a starting material.A multiple stage synthesis based on MePCl2 affords the disecondary phosphane MeHP-CH2-PMeH (10d), which in contrast to reports given in the literature is thermally stable to at least 100 deg C.The 31P and 1H NMR spectra of 1 have been analyzed and simulated by use of computer programs.The structure of the phosphanes is discussed on the basis of their 1H, 31P, 31P, and 13C NMR spectra.
- Hietkamp, Sibbele,Sommer, Herbert,Stelzer, Othmar
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p. 3400 - 3413
(2007/10/02)
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