The first rings to contain the structural unit PCP have been obtained by reaction of Ph2PCH2PPH2 with Br(CH2)nBr (n = 2, 3, 4). The chemical properties and the bond lengths and angles in carbodiphosphorane with n = 2 are best described by the following formulation:
The first systematic investigation of Mn-thiolate complexes is described. Anaerobic reaction of MnCl2 with 2.5 equiv of NaSPh in methanol affords [Mn4(SPh)10]1 2". The compound (Me4N)2[Mn4(SPh)10] crystallizes in triclinic space group PI with a = 13.184 (3) A, b = 23.743 (4) A, c = 12.930 (3) A, a = 91.63 (2)°, ß = 113.76 (1)°, y = 79.53 (2)°, and Z = 2. The structure was refined to R (Pw) = 4.5% (4.8%) with use of 5787 unique data (I > 3 (/)). The anion contains an adamantane-like 4(µ-8)6 cage composed of a nearly regular Mn4 tetrahedron and an irregularly distorted S6 octahedron and exhibits terminal and bridging Mn-S mean distances of 2.376 (7) and 2.46 (2) Á, respectively. Selected structural features are compared with those of five other 4(µ-8)6 cages. Anaerobic reaction of MnCl2 with 2 equiv of Na2(l,2-S2C2H4) in methanol forms extremely oxygen-sensitive [Mn(S2C2H4)2]2~. The compound (Me4N)2[Mn(S2C2H4)2]-MeCN crystallizes in monoclinic space group P2\/n with a = 9.833 (5) A, b = 17.325 (7) A, c = 13.819 (6) A, ß = 93.43 (2)°, and Z = 4. The structure was refined to R (Pw) = 4.4% (4.5%) with use of 1893 unique data (I > 3 (/)). The anion is tetrahedral with mean dimensions Mn-S = 2.432 (7) Á, chelate ring zS-Mn-S = 91.5°, and a 92.3°dihedral angle between MnS2 planes. Exposure of a solution of [Mn(S2C2H4)2]2~t o air results in the immediate formation of a dark green color and thereafter isolation of salts of [Mn2(S2C2H4)4]2'. (Et4N)2[Mn2(S2C2H4)4] crystallizes in monoclinic space group P2Jn with a = 12.039 (4) A, b = 10.699 (2) A, c = 15.012 (3) X, ß = 110.89 (2)°, and Z = 2. The structure was refined to R (R") = 4.4% (4.9%) with use of 2175 unique data (/ > 3 (/)). The centrosymmetric anion exhibits the lateral dimer structure in which bis chelate monomers are joined by two Mn-S bonds of length 2.632 (2) Á. The two Mn-Ss coordination units approach a trigonal-bipyramidal arrangement and are separated by a Mn-Mn distance of 3.596 (3) Á. [Mn2(S2C2H4)4]2™ is the first characterized Mn(III) thiolate. A compilation of the limited set of all known Mn-S bond distances is provided.[Mn(S2C2H4)2]2-and [Mn4(SPh)10]2" contain tetrahedral Mn(II) sites; [Mn(S2C2H4)2]2" remains tetrahedral and high spin in acetonitrile and DMF solutions. Magnetic and spectral properties of solutions prepared from [Mn2(S2C2H4)4]2ĩ ndicate that the dimer partially (acetonitrile) or completely (Me2SO, DMF) dissociates in solution to form monomeric [Mn(S2C2H4)2(solv)2]_. Cyclic voltammetry of these species are in accord with an E¡C¡ mechanism, in which the initial reduction product, [Mn(S2C2H4)2(solv)2]2~, rapidly and irreversibly converts to [Mn(S2C2H4)2]2~. This species is irreversibly oxidized to [Mn(S2C2H4)2(solv)2]~a t less cathodic potentials. The large £ values (0.52 V (acetonitrile), 0.76 V (DMF)) are consistent with different electroactive orbitals of [Mn(S2C2H4)2]2~a nd [Mn(S2C2H4)2(solv)2]~required by tetrahedral and six-coordinate structures, respectively. Spectral evidence is presented for Mn(III) species of the type [Mn(S2C2H...
Die Titelverbindung 1 wird aus 1,8-Dilithionaphthalin und Chlordimethylphosphan dargestellt. Sie ergibt bei der Methylierung mit Methyliodid nur ein Monoquartarsalz 2, dessen NMR-Daten wegen der sterischen Uberfiillung des Kations through-space-Wechselwirkungen andeuten. Mit CH,X, (X = C1, Br) entsteht nur ein Gemisch nicht identifizierter Phosphoniumsalze. -Die Reaktion von 1 mit T H F . BH, ergibt eine Gleichgewichtsmischung (1 : 3) des Bisphosphan-diborans 5 und des cyclischen Boranats 6 . 1,8-Naphthalenediylhis(dimethylphosphane): Steric Influence on Methylation and BorylationThe title compound 1 is synthesized from 1,8-dilithionaphthalene and chlorodimethylphosphane. 1 yields only a monoquaternary salt 2 in the reaction with methyl iodide. The NMR data of 2 suggest strong through space couplings due to steric crowding. With CH,X, (X = CI, Br) only a complex mixture of unidentified phosphonium salts is obtained. -The reaction of 1 with T H F .BH, gives an equilibrium mixture (1 : 3) of the bisphosphane-diborane 5 and the cyclic boranate 6.Im Rahmen einer Studie iiber cyclische Doppel-Ylide des Phosphors (Carbodiphosphorane, A) I) wurden auch Synthese und Untersuchung von Molekulen mit Phenalen-artigem Grundgeriist erwogen (B). Zu deren Darstellung sollten sich Phosphan-und Phosphoniumsalz-Vorstufen eignen, iiber die hier berichtet wird. Das eigentliche Ziel konnte wegen der Schwierigkeiten bei der cyclisierenden Quartarisierung bisher nicht erreicht werden.A peri-Substituierte Naphthaline sind durch starke sterische Wechselwirkungen zwischen den Substituenten gekennzeichnet, die teilweise zu dramatischen Verzerrungen des aromatischen Bicyclus fiihrenz). Bei den Bis(trimethylelement(1V))-Verbindungen C betragt nach Strukturdaten iiberdies die Auslenkung der Substituenten aus der Naphthalin-Ebene bis zu 43" (M = Sn)2b). Die Siliciumverbindung (M = Si) hat sich bis heute wegen der dort offenbar besonders groRen sterischen Spannungen der Synthese iiberhaupt entzogen3). Das Bis(dimethy1amino)-Derivat ist weit weniger gespannt (Auslenkungswinkel 4°)4). Die entsprechende Phosphorverbindung war aber bisher nicht bekannt. Ihre Quartarisierung sollte die sterischen Wechselwirkungen schrittweise (1 + 2 + 3) steigern.
durch die Nitrene (4) und (6) rnit Triplett-Grundzustand zu erwarten sind. Die besten Ausbeuten an Aminen wurden durch Zersetzung von (1) und (3)
Aus Bis(dipheny1phosphino)methan (1) und 1,3-Dibrompropan wird iiber ein Diphosphoniumsalz 6 und ein Semiquartarsalz 7 durch Urnylidierung mit salzfreiem Trimethylmethylenphosphoran das cyclische Carbodiphosphoran 8 dargestellt. Der Strukturbeweis gelingt iiber 'H-, ',C-, "P-NMR-und Massenspektrum sowie durch eine Rontgenbeugungsanalyse. Durch wasserfreien Chlorwasserstoff wird das Diphosphoniumsalz 6 zuriickgebildet. Mit Tetrahydrofuran-Boran wird ein 1 : 1 -Komplex 9 erhalten, der den BH,-Akzeptor am Doppelylid-Briickenkohlenstoffatom gebunden hat. In gleicher Position erfolgt die Methylierung mit Methyliodid (10). Mit Dimethylzink und -cadmium entstehen 1 : I-Komplexe (11, 12) vermutlich dimerer Struktur, die in Losung raschen CH,-Austausch zeigen. -Das schon bekannte offenkettige Analogon CH,(C,H,),P = C = P(C&),CH, (4) gleicht in vielen Eigenschaften, einschlieBlich seiner Molekiilstruktur, dem Heterocyclus 8. Bei der Komplexbildung mit Metallen erfolgt hier jedoch bevorzugt Eintritt in die CH,-Gruppen. Der Nickelkomplex 5 ist dafiir ein charakteristisches Beispiel. A Cyclic Carbodiphosphorane and an Open-chain Reference CompoundThe cyclic carbodiphosphorane 8 is prepared from bis(dipheny1phosphino)methane (1) and 1,3-dibromopropane, via a diphosphonium salt 6 and a semiquaternary salt 7, through transylidation with salt-free trimethyl methylene phosphorane. The structure is established by 'H-, I3C-, ,'P-NMR and mass spectrometry, as well as by x-rax diffraction. Reprotonation with anhydrous HCI regenerates the diphosphonium salt 6. With tetrahydrofuran-borane, 8 is converted into a 1 : 1-borane complex 9, with the BH, acceptor attached to the double-ylide carbon bridge. Methylation with CH,I occurs in the same position (10). 1 : 1-complexes (11, 12) are also formed with dimethylzink and -cadmium. The products are probably dimeric and show a rapid CH,-exchange in solution. -The already known open-chain analogue CH,(C,H,),P = C = P(C6H,),CH, (4) resembles 8 in many respects, including the molecular structure. In the coordination interaction with metals a metalation in the CH3-groups is strongly favoured, however, as it is again shown in the nickel complex 5.
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