Lanthanide and Actinide Chemistry and Spectroscopy

463 Pages·1980·5.9 MB·English

by  Norman M. Edelstein (Eds.)

Lanthanide and Actinide Chemistry
and Spectroscopy
Norman M. Edelstein, EDITOR
Lawrence Berkeley Laboratory
1
0
0
w
1.f
3
1
0
0-
8
9
1
k- Based on a symposium
b
1/
2
0
0.1 sponsored by the Division
1
oi:
d
0 | of Inorganic Chemistry at
8
9
1
23, the 178th Meeting of the
er
b
m
pte American Chemical Society,
e
S
e:
at Washington, D.C.,
D
n
o
cati September 10-13, 1979.
bli
u
P

131
ACS SYMPOSIUM SERIES
AMERICAN CHEMICAL SOCIETY
WASHINGTON, D.C. 1980
1
0
0
w
1.f
3
1
0
0-
8
9
1 Library of Congress CIP Data
k-
1/b Lanthanide and actinide chemistry and spectroscopy.
2 (ACS symposium series; 131 ISSN 0097-6156)
0
1
0. Includes bibliographies and index.
1
oi: 1. Rare earth metals—Congresses. 2. Actinide ele­
d ments—Congresses. 3. Spectrum analysis—Congresses.
0 | I. Edelstein, Norman M., 1936- . II. American
8
9 Chemical Society. Division of Inorganic Chemistry. III.
1
3, Series: American Chemical Society. ACS symposium
2 series; 131.
er
b QD172.R2L27 546'.41 80-17468
m
e ISBN 0-8412-0568-X ACSMC8 131 1-472 1980
pt
e
S
e:
at
D
n
o Copyright © 1980
ati
blic American Chemical Society
u
P All Rights Reserved. The appearance of the code at the bottom of the first page of each

article in this volume indicates the copyright owner's consent that reprographic copies of
the article may be made for personal or internal use or for the personal or internal use of
specific clients. This consent is given on the condition, however, that the copier pay the
stated per copy fee through the Copyright Clearance Center, Inc. for copying beyond that
permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend
to copying or transmission by any means—graphic or electronic—for any other purpose,
such as for general distribution, for advertising or promotional purposes, for creating new
collective works, for resale, or for information storage and retrieval systems.
The citation of trade names and/or names of manufacturers in this publication is not to be
construed as an endorsement or as approval by ACS of the commercial products or services
referenced herein; nor should the mere reference herein to any drawing, specification,
chemical process, or other data be regarded as a license or as a conveyance of any right or
permission, to the holder, reader, or any other person or corporation, to manufacture, repro­
duce, use, or sell any patented invention or copyrighted work that may in any way be
related thereto.
PRINTED IN THE UNITED STATES OF AMERICA
ACS Symposium Series
1
0
0
w M. Joan Comstock, Series Editor
1.f
3
1
0
0-
8
9
1
k-
b
1/ Advisory Board
2
0
1
0.
1 David L. Allara W. Jeffrey Howe
oi:
d
0 | Kenneth B. Bischoff James D. Idol, Jr.
8
9
1
3, Donald G. Crosby James P. Lodge
2
er
b
m Donald D. Dollberg Leon Petrakis
e
pt
e
S
e: Robert E. Feeney F. Sherwood Rowland
at
D
on Jack Halpern Alan C. Sartorelli
ati
c
bli Brian M. Harney Raymond B. Seymour
u
P

Robert A. Hofstader Gunter Zweig
FOREWORD
1
00 The ACS SYMPOSIUM SERIES was founded in 1974 to provide
w
1.f a medium for publishing symposia quickly in book form. The
3
01 format of the Series parallels that of the continuing ADVANCES
80- IN CHEMISTRY SERIES except that in order to save time the
9
k-1 papers are not typeset but are reproduced as they are sub
b
1/ mitted by the authors in camera-ready form. Papers are re
2
10 viewed under the supervision of the Editors with the assistance
0.
1 of the Series Advisory Board and are selected to maintain the
doi: integrity of the symposia; however, verbatim reproductions of
0 | previously published papers are not accepted. Both reviews
8
9
1 and reports of research are acceptable since symposia may
3,
2 embrace both types of presentation.
er
b
m
e
pt
e
S
e:
at
D
n
o
ati
c
bli
u
P
PREFACE
The last published symposium on lanthanide and actinide chemistry,
sponsored by the Division of Inorganic Chemistry and the Divi
sion of Nuclear Chemistry and Technology of the American Chemical
Society, was held in 1966. The purpose of this earlier symposium was
"to summarize the significant areas of current chemical research. . .
1 The same statement may be made about the present symposium; how
0
0
pr ever, the topics covered differ considerably. For example, there was not
31. one chapter on organolanthanide or organoactinide chemistry in the
1
0
0- earlier symposium, while in the present volume a goodly fraction of the
8
9 chapters are on this topic. Further, the availability of significant amounts
1
bk- of the transcurium elements have led to the elucidation of the properties
1/
2 of the elements and their compounds with atomic numbers greater than
0
1
0. 96. Also, as in other areas of science, new, sophisticated instrumentation
1
oi: is in the process of revolutionizing the quality and type of data obtained
d
0 | on the /-block elements and compounds.
8
9 This volume is intended to introduce the nonspecialist chemist to
1
3, recent trends in lanthanide and actinide chemistry and spectroscopy, to
2
er summarize this work, and to identify directions for future studies. Inevi
b
m
e tably, the chapters in this collection reflect (to some extent) the tastes
pt
e of the organizer.
S
e: I would like to thank the participants in the symposium for their
at
D
n contributions, Dr. William T. Carnall for his help in organizing the spec
o
ati troscopy part of the symposium, and Drs. John Fackler, Gary Long, and
c
bli Leonard Interrante of the Division of Inorganic Chemistry for their
u
P efforts on behalf of the symposium and the publication of the proceed

ings. Acknowledgment is made to the Donors of the Petroleum Research
Fund, administered by the American Chemical Society, for partial sup
port of this symposium.
Lawrence Berkeley Laboratory NORMAN M. EDELSTEIN
Berkeley, CA 94720
December 21, 1979.
vii
1
Nonclassical Activation of Carbon Monoxide by
Organoactinides
TOBIN J. MARKS, JUAN M. MANRIQUEZ, and PAUL J. FAGAN
Department of Chemistry, Northwestern University, Evanston, IL 60201
VICTOR W. DAY, CYNTHIA S. DAY, and SARAH H. VOLLMER
Department of Chemistry, University of Nebraska, Lincoln, NE 68588
1
0
0
h Abstract
c
1.
3
1
0-0 This article reviews recent results on the carbonylation
8 chemistry of bis(pentamethylcyclopentadienyl) thorium and uranium
9
k-1 hydrocarbyl and dialkylamide complexes. Facile migratory inser
1/b tion of carbon monoxide into metal-carbon and metal-nitrogen bonds
02 is observed. In several cases bihaptoacyl and bihaptocarbamoyl
1
0. complexes were isolated and characterized by single crystal X-ray
1
oi: diffraction. The great strength of the metal-oxygen bonding in
d these species is evident in metrical and spectral data, as well
80 | as in the reaction chemistry, which is decidedly alkoxycarbene­
9
1 -like. In the case of the bis(pentamethylcyclopentadienyl) actin
23, ide dialkyls, the final carbonylation products are C-C coupled
er cis-1,2-enediolate complexes, while for the corresponding bis(di-
b
m alkylamides), the products are bis(carbamoyl) species. Both
e
pt types of compound have been characterized by X-ray diffraction.
e
e: S The carbon monoxide chemistry observed here may be of relevance
at to mechanistic discussions of catalytic CO reduction, especially
D
n that involving actinide oxide or actinide oxide supported cata
o
ati lysts.
c
bli
Pu Introduction

Our recent research in actinide organometallic chemistry
Q-5) has sought to exploit those features of f-element ions
which differ from transition metal ions. The goal of our effort
has been to discover and to understand to what degree the large
ionic radii and f valence orbitals might foster a unique new
organometallic chemistry. Exploration has been at both the chem
ical and physicochemical levels with the central issues concerning
the properties of actinide-to-carbon sigma bonds and related
functionalities. We have learned that the thermal stability and
chemical reactivity of these linkages can be modulated to a con
siderable degree (and often in opposite directions) by changes in
the supporting ligands within the actinide ion coordination sphere.
0-8412-0568-X/80/47-131-003$06.25/0
© 1980 American Chemical Society
4 LANTHANIDE AND ACTINIDE CHEMISTRY AND SPECTROSCOPY
Thus, while the coordinative saturation of the triscyclopentadienyl
alkyls, alkenyls, alkynyls, and aryls (hydrocarbyls) of thorium
and uranium, M(7]5-CH)R (^J_S_9), affords considerably enhanced
5 5 3 9 9 9
thermal stability over that of the simple homoleptic derivatives
(10,11,12), it is at the expense of chemical reactivity.
In an effort to more finely tune the coordinative saturation
of actinide hydrocarbyls and to provide greater than one metal-
carbon bond for reaction, we have initiated an investigation of
biscyclopentadienyl thorium and uranium chemistry (6,13,14). Sys
tems based upon the pentamethylcyclopentadienyl ligand have proved
to be some of the most interesting and form the basis of this
article. The advantages of the 775-(CH)C5 ligand are that it
3 5
makes far greater steric demands than 7)5-CH (thus reducing the
5 5
number of large, bulky ligands which can be accommodated at the
1 metal center) while imparting far greater solubility and crystal-
0
0 lizability. It also appears that the methyl C(sp3)-H bonds of
h
1.c this ligand are more inert with respect to scission than cyclo-
13 pentadienyl C(sp2)—H bonds; this has the effect of hindering a
0
0- common thermal decomposition process, intramolecular hydrogen
8
9 atom abstraction (7_,8,15., 16,17), hence of preserving the metal-
1
k- to-carbon sigma bond for other chemical transformations. The net
b
1/ result is that pentamethylcyclopentadienyl actinide hydrocarbyls
2
10 form the basis for an elaborate and extremely reactive new class
10. of organometallic compounds.
oi: The purpose of this article is to review the chemical,
d
0 | physicochemical, and structural properties of bis(pentamethyl
8
9 cyclopentadienyl) actinide compounds with respect to one reagent:
1
3, carbon monoxide. The interaction of organometallic complexes with
2
er carbon monoxide is a subject of enormous technological importance.
mb Vast quantities of acetic acid, alcohols, esters, and other im
pte portant chemicals are presently produced using organic feedstocks,
e
S carbon monoxide, and homogeneous catalysts of the Group VIII
ate: transition metals (18,19,20). Much of this chemistry is now well-
D understood from model studies and is based upon the ,fclassicalM
n
o migratory insertion reaction of carbon monoxide into a metal-to-
cati carbon sigma bond to form an acyl derivative (A) (equation (l))
ubli (21,22,23). An industrially important example of this type of
P
chemistry is the rhodium catalyzed hydroformylation cycle illus*
trated in Figure 1 (18). It is not clear, however, that the
CHj GHg CH3
I I I
M + CO^dMf-CO f=^M-C=0 (l)
A
classic picture of CO activation established for low-valent,
"soft11, mononuclear, Group VIII metal complexes is complete or
accurate in describing the mechanisms of Fischer-Tropsch (24-28),
methanation (24-28), ethylene glycol synthesis (29), and other
1. MARKS ET AL. Nonclassical Activation of Carbon Monoxide 5
reactions in which drastic changes in the CO molecule such as
facile deoxygenation and homologation are occurring. Clearly
there is a necessity to develop new carbon monoxide chemistry and
to elucidate new reaction patterns. Such research is essential to
understanding the fundamental aspects of processes which will be
of ever-increasing importance in an economy shifting to coal-based
feedstocks. It will be seen that the carbonylation reactions of
bis(pentamethylcyclopentadienyl) actinide hydrocarbyls and related
compounds differ dramatically from the "classical" pattern and af
ford a better insight into the reactivity of carbon monoxide at
metal centers which exhibit both high oxygen affinity and high
coordinative unsaturation. In the sections which follow we con
sider first the chemical and then the structural aspects of this
problem.
1
0
0
h Synthesis and Chemistry
c
1.
3
01 The sequence shown in equations (2) and (3) offers an effec
80- tive route to monomeric, highly crystalline, thermally stable
9
1 thorium and uranium organometallies with either one or two metal-
k-
b
1/
2 2(CH)C- + MC1 t0^gg>M[(CH)C1Cl + 2Cl" (2)
10 3 5 5 4 3 5 5 2 2
0.
1
oi: M = Th,U
d
0 |
8
19 M[(CH)C]C1 + 2RLi etggj °r> M[(CH)C1R 4- 2L1C1 (3)
3, 3 5 5 2 2 3 5 5 2 2
2
er M « Th, R * CH, CHSi(CH), CHC(CH), CHCH, CH
b 3 2 3 3 2 3 3 2 6 5 6 5
m M « U, R * CH, CHSi(CH), CHCH
pte 3 2 3 3 2 6 5
e
e: S carbon sigma bonds (6,30,31.) . All compounds shown in these and
at subsequent reactions were thoroughly characterized by elemental
D
n analysis, cryoscopic molecular weight in benzene (solubility per
o
ati mitting), infrared and NMR spectroscopy, and, in several cases, by
blic single crystal X-ray diffraction. Structures B and C are proposed
u for these new compounds in solution.
P

B C
M = U M = Th,U
6 LANTHANIDE AND ACTINIDE CHEMISTRY AND SPECTROSCOPY
The reaction of Th[(CH)C](CH) and U[(CH)C](CH)
3 5 5 2 3 2 3 5 5 2 3 2
with carbon monoxide is quite rapid (6,32,33.) • At -80°C in tolu
ene solution, these compounds absorb 2.0 equivalents of carbon
monoxide fet less than one atmosphere pressure) within 1 hour.
Upon warming to room temperature, the dimeric products (l) are
isolated in essentially quantitative yield (equation (4);. The
infrared spectra (Vg-Q - 1655 cm"1; i/_ = 1252, 1220 cm"1) as
c0
well as the single methyl resonance in the1 H NMR spectrum strong
ly suggests that C-C coupling of the inserted carbon monoxide
2M[(CH)C](CH) + 4C0 t0lU^6 >fM[ (CH)C] (0C(CH)= C(CH^O^
3 5 5 2 3 2 3 5 5 2 3
-80
(4)
la M = Th (colorless crystals)
1 lb M = U (brown crystals)
0
0
h
c
1. molecules has occurred to form enediolate moieties (D). Confirm
3
01 ation of this hypothesis was achieved by single crystal X-ray dif-
0-
8
9
1 CH CH
k- 3 3
1/b Nc=c
02 -o' vo-
1
0.
oi: 1 D
d
0 | fraction studies on ^a. (6,32,33). As can be seen in Figure 2,
8
9 four carbon monoxide molecules have been coupled to form four
1
3, thorium-oxygen bonds and, stereospecifically, two cis-substituted
2
ber carbon-carbon double bonds. Two Th[(CH3)5C5]2 units in the com
m mon "bent sandwich" configuration (34) are components of a ten-
e
pt atom metallocycle. The enediolate ligands are essentially planar
e
S with genuine C-C double bonds (Ci-C = C,-C' = 1.33(2)A). Fur
ate: ther structural remarks are reserved2 for 1the2 following section.
D
n As a prelude to discussing additional f-element chemistry, it
atio is at this point worth noting the results of carbonylation ex
c periments with the biscyclopentadienyls of early transtion metals.
ubli As is the case for the actinides, these elements in the higher
P
oxidation states exhibit a great affinity for oxygen-donating lig
ands (35,36), and their chemistry will place further actinide re
sults in a more meaningful perspective. Floriani and coworkers
have carried out an extensive investigation of the reaction of
biscyclopentadienyl titanium, zirconium, and hafnium bishydro-
carbyls and halohydrocarbyls with carbon monoxide (equations(5)
and (6)) (37.>38^39_). Only monocarbonylation is observed. Similar
M(CH)R + CO ^=± M(CH)(C0R)R (5)
5 5 2 2 5 5 2
M = Zr, Hf
R = CH, CHCH, (CH not reversible)
3 2 6 5 6 5
MARKS ET AL. Nonclassical Activation of Carbon Monoxide
HRh(CO)L
3
/
L=<£P
I- 3
CHCH0 ^H R^C0 ) L^
3 7
HRh(CO)L ,
2
CHC-Rh(C0)L HC — CHCH
3 7 II *\ 2 2 3
0 J
5
CHRh(C0)l-2 CHRh(CO)L
3 7 2 3 7 2
1 4
0
0
h
c
1.
3
01 Journal of Molecular Catalysis
0-
8 Figure 1. A proposed mechanism for the rhodium-catalyzed hydr of or my lotion
9
1 of propylene (IS)
k-
b
1/
2
0
1
0.
1
oi:
d
0 |
8
9
1
3,
2
er
b
m
e
pt
e
S
e:
at
D
n
o
ati
c
bli
u
P

Journal of the American Chemical Society
Figure 2. ORTEP drawing of the nonhydrogen atoms for the [Th(7f-(CH)-
35
C)2(p-02C(CHs)2)]2 molecule, la. All atoms are represented by thermal vibra
5 2
tional ellipsoids drawn to encompass 50% of the electron density. Atoms of a
given type labelled with a prime (') are related to those labelled without by the
crystallographic inversion center midway between the two thorium atoms. The
crystallographically independent pentamethylcyclopentadienyl ligands are la
belled A and B, respectively (32).