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Structure and bonding of bisaquamercury(II) and trisaquathallium(III) trifluoromethanesulfonate

Molla-Abbassi, A.

Eriksson, L.

Mink, János

2002

QD Chemistry / kémia

QD03 Inorganic chemistry / szervetlen kémia

TK Electrical engineering. Electronics Nuclear engineering / elektrotechnika, elektronika, atomtechnika

The structure and bonding in bisaquamercury(II)
trifluoromethanesulfonate, [Hg(OH2)(2)(CF3SO3)(2)](infinity),
and
trisaquathallium(III) trifluoromethanesulfonate,
[Tl(OH2)(3)(CF3SO3)(3)], have been studied by means of single-
crystal
X-ray diffraction, EXAFS and vibrational spectroscopy. The
crystal
structure of bisaquamercury(II) trifluoromethane sulfonate shows
an
unusual connectivity pattern. The mercury(II) ion strongly binds
two
water molecules axially with the Hg-O bond distance 2.11
Angstrom, and
four oxygen atoms from four trifluoromethanesulfonate ions
complete a
tetragonally compressed octahedral coordination geometry, at the
mean
Hg-O distance 2.53 Angstrom. Two trifluoromethanesulfonate ions
form
double bridges between the bisaquamercury(II) entities giving
rise to
infinite >Hg(OH2)(2) <(CF3SO3)(2) >Hg(OH2)(2)< chains. The
parallel
chains are held together in layers by relatively strong hydrogen
bonds
with O(-H) &BULL;&BULL;&BULL; O distances in the range
2.688(9)-2.735(9) &ANGS;. The O-D stretching vibrational
frequencies of
the hydrogen bonds in the partly denterated compound occur in a
broad
band at about 2400 cm(-1), bandwidth ca. 170 cm(-1). The layers
are
connected only via van der Waals interactions between the
protruding
CF3 groups, consistent with the fragile sheet-like structure of
the
crystalline compound. Trisaquathallium(III)
trifluoromethanesulfonate
crystallises as molecular complexes where each thallium(m) ion
binds
three water molecules and three oxygen atoms from
trifluoromethanesulfonate ions, with T1-O bond distances in the
range
2.18-2.24 &ANGS;. A hydrogen bond network between the water
molecules
and trifluoromethanesulfonate ions with O(-H) &BULL;&BULL;&BULL;
O
distances in the range 2.65(1)-2.80(1) &ANGS; holds the
structure
together. Raman and infrared spectra have been recorded and
analysed.
The changes in force constants and vibrational frequencies have
been
correlated with bond lengths for the S-O bond in the coordinated
trifluoromethanesulfonate ion and for the Hg-O and T1-O bonds,
also
including the hexaaquaions in the comparisons.

Article

PeerReviewed

text

http://real.mtak.hu/7000/1/1197234.pdf

Molla-Abbassi, A. and Eriksson, L. and Mink, János (2002) Structure and bonding of bisaquamercury(II) and trisaquathallium(III) trifluoromethanesulfonate. JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS. pp. 4357-4364. ISSN 0300-9246

http://pubs.rsc.org/en/Content/ArticleLanding/2002/DT/b2060...

http://real.mtak.hu/7000/