Structures of two cyclopropylcarbinyl cations

Experimental evaluation of the electron donor ability of a gold phosphine fragment in a gold carbene complex

“…Rather, DFT calculations suggest that a tertiary allylic carbocation is stabilized to a similar extent by a (Me 3 P)Au group and a methoxy group. 6 Toward an experimental evaluation of Au -C1 electron donation in a gold carbene complex, we were drawn to the large body of experimental [12][13][14][15][16] and theoretical 17,18 work regarding the geometric perturbations of a cyclopropyl ring bound to a p-acceptor group. In the preferred bisected conformation, 19 overlap of the occupied Walsh 3e 0 orbital with the empty p or p* orbital of the acceptor leads to shortening of the C1-C2 and distal C3-C4 bonds with concomitant lengthening of the vicinal C2-C3/4 bonds that is commensurate with the extent of delocalization (Fig.…”

Syntheses, Structures and Electronic Properties of Cationic Hydroxy‐ and Methoxy‐Substituted Tricarbonyl(tetracyclopropylcyclopentadienyl)iron Complexes

“…[15] The lack of delocalization of the positive charge into the cyclopropyl groups in the cationic complexes 11 and 12 as well as in 9 and 10 is also evident in the 1 H-and 13 C-NMR spectroscopic data. The signals of the protons on the cyclopropyl groups as well as the carbon atoms in them are not shifted to lower fields on going from the neutral 3 to the cationic complexes (Table 1).…”

“…In the latter, the bond order of this C,O bond apparently is between that of a single and a double bond, indicating that a considerable fraction of the positive charge remains on the oxygen atom, like in protonated dicyclopropyl ketone 13, in which the C,O bond length is 129.0 pm indicating an even higher double bond character than in 11 and 12. [15] The five-membered ring in 3 is not planar with the ring carbonyl group being bent away from the Fe(CO) 3 tively, and the distance between the iron and the carbonyl carbon atom to shorten from 238.8 to 219.7 and 219.4 pm, respectively. With the other four iron to carbon distances remaining virtually the same, the coordination hapticity of the iron atom changes from η 4 to almost η 5 .…”

Origin of the Stabilization of Vinyldiazonium Ions by β‐Substitution; First Crystal Structure of an Aliphatic Diazonium Ion: β,β‐Diethoxyethene‐diazonium Hexachloroantimonate

“…ci c 2 -n 1.378 (15) 1.371 (16) 1.102 ( 15) 1.268 (12) 1.257(13) 1.477 (12) 1.468 (13) 1.500 (16) 1.561 (17) --118.8(10) 89.6(14) 118.0(10) 13 7.4(8) 12 1.9 (8) 122.1 (9) 107.4(8) 107.3 (9) 1.374 ( 14) 1.325 (15) 1.104 ( 15) 1.324(13) 1.296( 13) 1.493(11) 1.469(13) 1.479 (14) 1.488 (16) -116.6(9) 89.3(12) 119.0(10) 125.6(10) 11 7.9(7) 117.8 (8) fragments. Moreover, the 13C NMR chemical shifts of 1 are indicative of electron depletion at C, which is also in agreement with the additions of nucleophiles to the j carbon atom in the chemistry of P,P-disubstituted ethenediazonium ions.…”