Carbonyl ylides (I; Scheme 1) can be obtained by reactions of carbenes and carbenoids with aldehydes and ketones['.21 or by electrocyclic ring opening of ~xiranes.[~] As 1,3-dipole~[~~ they are mechanistically and preparatively of interest for heterocycle syntheses, and can be detected by intra-and intermolecular trapping reactions.['] In reactions of carbonyl compounds with organophosphorus carbene analogues, such as phosphanediyls, electrophilic, terminal phosphanediyl metal complexes,[5] iminophosphanes,C6' or metallodiph~sphenes,[~~ the formation of phosphorus analogues (XI-V) of carbonyl ylides has not yet I II PR 111 I V V Scheme 1. Carbonyl ylides (I) and organophosphorus analogues (11-V) (R = alkyl, aryl; [MI = metal complex fragment).
COMMUNICATIONS[31] This is evident from the fact that the energy increases from 43 to 4.9 kJmol-' for configuration B by inclusion of the BSSE and even results in an endothermic binding energy for the dider. The binding energies for configuration A and C(D) are -4.8 and -1.0 (MP2), -4.0 and 1.8 (B3LYP) and -4.4 and -0.6 kJmol-' for CCSD(T). [39] Crystal system: monoclinic, space group P2,/c, Z = 4, at -188"C, a = 6378(1), b = 4.247(1), c = 6.425(1)& fl =104.55(3)", V=168.5(1)A3, pEalid = 2.141 gcm-3, ,u = 1.73 mm-'. Diffractometer Nicolet-Siemens R3m/ V, Mo,, radiation, graphite monochromator, 1 = 0.7107 A. A total number of 3747 reflections in the 20 interval 2-90" were measured by using the Wyckoff scan technique (a half sphere of the reciprocal space in the interval 20 = 2-60", and two independent octants in the interval 20 = 60-90"). During data collec-D = 103.46(2)", V = 3.0268(9) nm3; Z = 4, pCvrcd =
Triisopropylphosphan (1) ergibt mit Iod i‐Pr3PI+I– (2), dessen Iod‐Iod Wechselwirkung aufweisende Ionenpaare als Dichlormethan‐Solvat kristallisieren. Mit weiterem Iod entsteht i‐Pr3PI+I3– (3), aus 2 und AgSbF6 erhält man i‐Pr3PI+SbF6– (6). In Gegenwart von Luftfeuchtigkeit entstehen rasch Triisopropylhydroxyphosphoniumsalze, von denen i‐Pr3POH+I– (4) P–O–H…I‐Wasserstoffbrücken aufweist und (i‐Pr3PO)2H+I3– (5) P=O…H…O=P‐verbrückte Kationen enthält. Die Unterscheidung zwischen Iodphosphoniumionen und Hydroxyphosphoniumionen in Lösung wird dadurch erschwert, daß beide Arten von Kationen ähnliche 31P‐NMR‐Verschiebungen aufweisen und daß beide Kationen Wechselwirkungen mit ihren Anionen und rasche Austauschgleichgewichte eingehen: I+‐Transferreaktionen an 1 und H+‐Transferreaktionen an i‐Pr3P=O (7).
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