The structure of CsB9H14: X-ray and proton and boron-11 nuclear magnetic resonance studies

Abstract

Szmmary The X-ray crystal structure of CsB,HI4 shows the presence of three BH, groups and two B-H-B groups in the open face of the B, cluster: in solution, the llB(28.87 MHz) and lH(220 MHz) n.m.r. spectra indicate pseudo-threefold symmetry with nine terminal B-H bonds and five more labile hydrogen atoms.THE structure of the BgH14-anion has been predicted1 on the basis of the known structure of the isoelectronic adduct MeCNB,H13, but no definitive evidence has been presented for its structure, although n.m.r. data have been reported., This paper gives the results of a single-crystal X-ray structure determination of CsB,H14 and relates this to the UB and 1H n.m.r. spectra of the B9H14-anion in various solvents over a range of temperature.

Triphenylmethylphosphonium trichloro(caffeine)platinum(II) [P(C6H5)3(CH3)][PtCl3(caffeine)], structure and anticancer activity

“…[23][24][25] Several workers have stated that the P-CH3 bond is expected to be longer than the P-C6H5 bond because of the differing hybridization of the carbon atoms. 22,23,27,28 The P-CH3 bond has been observed to be longer in several structures, 22,23,25 including the compound reported here, where the P-CH3 bond (1.786 (6) Á) is insignificantly longer than the average of the P-C6H5 bonds (1.780 (10) A). However, in all cases the differences in the P-CH3 and P-C6H5 bond lengths are small enough to be accounted for by experimental error.…”

“…We have averaged the P-CH3 and P-C6H5 lengths found in all reported structures of the [P(C6H5)3CH3]+ cation for which the standard deviations are less than 0.01 A. [22][23][24]28 Acknowledgment. This investigation was supported by National Institutes of Health National Research Service Award No.…”

Dynamical processes in boranes, borane complexes, carboranes, and related compounds

“…BgH14-An X-ray crystal study of CsBgH14 gives the structure in 43 for the anion BgH14-. '02 The most highly resolved h W 43 (see ref 102) ''6 nmr spectrum ( Figure 23) consists of three doublets of equal weight of which two overlap.10z This spectrum would be consistent with a structure having a threefold rotation axis and only one terminal hydrogen atom bonded to each boron atom. A system which is equilibrating rapidly on the nmr time scale could have a static structure as shown in 43 with rapid exchange between the two bridge protons and the upward pointing terminal protons.…”

Boranes. XXXIV. Preparation of some nido-dicarbanonaborane(11)'s and nido-dicarbadecaborane(12)'s

“…This nine-particle icosahedral fragment and the placement of bridge and -BH2 protons are based on crystallographic data for B9H13 C3HCN23 and CsBgHn. 28 The placement of vicinal carbon atoms at positions 4 and 5 is suggested from the products obtained by pyrolyzing B7H2Cn21 and from a mechanism for the B8H12-acetylene reaction (see below). We hasten to point out that nothing in our spectroscopic data precludes the possibility of a nonicosahedral geometry, and a X-ray crystal study is needed.…”