10680
J. Am. Chem. Soc. 2000, 122, 10680-10688
Reactions of Group IV Metal Atoms with Water Molecules. Matrix
Isolation FTIR and Theoretical Studies
Mingfei Zhou,* Luning Zhang, Jian Dong, and Qizong Qin
Contribution from the Laser Chemistry Institute, Department of Chemistry, Fudan UniVersity,
Shanghai, People’s Republic of China
ReceiVed June 9, 2000
Abstract: Laser-ablated group IV metal atoms have been co-deposited at 11 K with water molecules in excess
argon. The metal atoms reacted with water to form the insertion product HMOH and H2M(OH)2 (M ) Ti, Zr,
Hf) molecules spontaneously. Photolysis of the HTiOH species produced the H2TiO molecule as well as the
TiO monoxide. In the cases of Zr and Hf, however, the H2ZrO and H2HfO molecules were produced on
annealing, and the H2 elimination process was not observed on photolysis. In addition, the HMO species were
also observed and identified. The aforementioned species were identified via isotopic substitutions as well as
theoretical frequency calculations. Qualitative analysis of the possible reaction paths leading to the observed
products is proposed.
Introduction
reactivity depending on the spin, electron configuration, and
spin-orbital level has been discussed. These results showed
that earlier transition metal cations (Sc+, Ti+, and V+) are more
reactive than their oxides, and the formation of the low-lying
state MO+ + H2 is the only exothermic process.7-9,17,18 It is of
great interest to compare the chemistry of transition metal
cations and neutral atoms.
Recently, we have performed a matrix isolation FTIR and
theoretical study of reactions of laser-ablated Sc with water.20
The difference between laser-ablated and thermal evaporated
Sc atom reactions is the observation of HScO and ScOH
molecules with laser ablation. In this paper, we present a
combined matrix isolation FTIR spectroscopic and theoretical
investigation on the reactions of laser-ablated group IV metal
atoms with water molecules.
The interactions of transition metals with small molecules
are of chemical interest as such reactions may play important
roles in catalytic and chemisorption processes. Recent studies
of transition metal atoms with small molecules have provided
insight into the activation of bonds such as H-H,1 C-O,2 and
N-O.3 There are several reports on the reactions of transition
metal atoms with water molecules. Liu and Parson reported that
atomic Sc reacted with water to give ScO in the gas phase.4
Using the matrix isolation infrared absorption method, Kauffman
et al. showed that thermal Sc, Ti, and V atoms could react with
water to form the insertion products spontaneously, while the
metal monoxides were formed on photolysis, but later transition
metal atoms formed adducts with water, which were rearranged
to the insertion molecules on photolysis.5,6 To our knowledge,
there is no report on the reactions of the second- and third-row
transition metals with water.
Experimental and Theoretical Methods
The reactions of transition metal cations and water have
The experimental setup for pulsed laser ablation and matrix infra-
red spectroscopic investigation has been described previously21 and
is similar to the technique employed by the Andrews group.22 The
1064-nm Nd:YAG laser fundamental (Spectra Physics, DCR 150, 20
Hz repetition rate and 8 ns pulse width) was focused onto the rotating
metal target through a hole in a CsI window, and the ablated metal
atoms were co-deposited with H2O in excess argon onto a 11 K CsI
window, which was mounted on a cold tip of a closed-cycle helium
refrigerator (Air Products, Model CSW202), for 1 h at a rate of
received much attention recently. The M+ + H2O f MO+
+
H2 and its reverse reactions have been studied both experi-
mentally7-11 and theoretically.12-19 The different gas-phase
* Corresponding author. E-mail: mfzhou@srcap.stc.sh.cn. Fax: 0086-
21-65102777.
(1) See, for example: Chertihin, G. V.; Andrews, L. J. Am. Chem. Soc.
1994, 116, 8322; 1995, 117, 6402.
(2) See, for example: Zhou, M. F.; Andrews, L. J. Am. Chem. Soc. 1998,
120, 13230; 2000, 122, 1531.
(3) See, for example: Kushto, G. P.; Zhou, M. F.; Andrews, L.;
Bauschlicher, C. W., Jr. J. Phys. Chem. A 1999, 103, 1115. Zhou, M. F.;
Andrews, L. J. Phys. Chem. A 1998, 102, 7452.
(4) Liu, K.; Parson, J. M. J. Chem. Phys. 1978, 68, 1794.
(5) Kauffman, J. W.; Hauge, R. H.; Margrave, J. L. J. Phys. Chem. 1985,
89, 3541.
(6) Kauffman, J. W.; Hauge, R. H.; Margrave, J. L. J. Phys. Chem. 1985,
89, 3547.
(7) Clemmer, D. E.; Aristov, N.; Armentrout, P. B. J. Phys. Chem. 1993,
97, 544.
(8) Chen, Y. M.; Clemmer, D. E.; Armentrout, P. B. J. Phys. Chem.
1994, 98, 11490.
(9) Guo, B. C.; Kerns, K. P.; Castleman, A. W. J. Phys. Chem. 1992,
96, 4879.
(10) Ryan, M. F.; Fiedler, A.; Schroder, D.; Schwarz, H. J. Am. Chem.
Soc. 1995, 117, 2033.
(11) Schroder, D.; Fiedler, A.; Ryan, M. F.; Schwarz, H. J. Phys. Chem.
1994, 98, 68.
(12) Clemmer, D. E.; Chen, Y. M.; Khan, F. A.; Armentrout, P. B. J.
Phys. Chem. 1994, 98, 6522.
(13) Tilson, J. L.; Harrison, J. F. J. Phys. Chem. 1991, 95, 5097.
(14) Fiedler, A.; Schroder, D.; Shaik, S.; Schwarz, H. J. Am. Chem. Soc.
1994, 116, 10734.
(15) Danovich, D.; Shaik, S. J. Am. Chem. Soc. 1997, 119, 1773.
(16) Ye, S. THEOCHEM 1997, 417, 157.
(17) Irigoras, A.; Fowler, J. E.; Ugalde, J. M. J. Phys. Chem. A 1998,
102, 293.
(18) Irigoras, A.; Fowler, J. E.; Ugalde, J. M. J. Am. Chem. Soc. 1999,
121, 574.
(19) Irigoras, A.; Fowler, J. E.; Ugalde, J. M. J. Am. Chem. Soc. 1999,
121, 8549.
(20) Zhang, L. N.; Dong, J.; Zhou, M. F. J. Phys. Chem. A, to be
published.
(21) Chen, M. H.; Wang, X. F.; Zhang, L. N.; Yu, M.; Qin, Q. Z. Chem.
Phys. 1999, 242, 81.
(22) Burkholder, T. R.; Andrews, L. J. Chem. Phys. 1991, 95, 8697.
10.1021/ja0020658 CCC: $19.00 © 2000 American Chemical Society
Published on Web 10/14/2000