Microwave Spectrum of Bromostannane, SnH3Br

Abstract

Pure rotational measurements have been made on nine isotopic species of the unstable symmetric-top molecule bromostannane, SnH3Br, using a microwave spectrometer. The Sn–Br bondlength is 2.4691 ± 0.0003 Å. Quadrupole hyperfine structure due to the bromine nuclei gives values of eQq (79Br) = 350 ± 6 MHz and eQq (81Br) = 291 ± 6 MHz. A centrifugal-distortion constant, DJK = 0.0069 ± 0.0004 MHz affords a best fit to the complex K structure of observed transitions.

The ground-state rotational spectrum and molecular geometry of ethynylstannane

“…It appears that the only members of the first series for which there is an independent determination of these two quantities in gas-phase molecules without assumption are SnH 4 24 and H 3 SnBr. 25 It seems likely that the distance r 0 (Sn-H) will change little when an atom H in stannane is replaced by either an ethynyl group or an I atom. In the case of SnH 4 , the angle +HSnH has necessarily the tetrahedral value 109.471 and the distance is determined to be 1.70825(2) A ˚.24 Thus, there is effectively no change in the bond distance and only a small decrease in the angle when H is replaced by CCH.…”

Experimental Gas-phase Halogen Nuclear Quadrupole Coupling Constants; A Review

“…At the halogen centres, the germanes behave more closely to the silanes than methanes; thus a factor of 1.5-2.0 occurs in the alky 1/germyl compounds. The SnH 3 X series with X=C1, Br, I show NQCC at the major halogen isotope centres of -41.62 (30), +350(6) and-1273 (8) MHz, respectively [59,60,62]. These are again more reminiscent of silanes and germanes than methanes [61,62], The overall sequence of positions for the halogen NQCC in the alkanes, silanes, germanes and stannanes is: C>Ge>Sn>Si; this has been attributed to p/s-hybridisation differences, Cl>Br>I, together with electronegativity differences C>Ge>Sn>Si.…”