Aqueous Organometallic Chemistry. 2. <sup>1</sup>H NMR
Spectroscopic, Synthetic, and Structural Study of the
Chemo- and Diastereoselective Reactions of [Cp*Rh(H<sub>2</sub>O)<sub>3</sub>]<sup>2+</sup> with Nitrogen Ligands as a Function of pH
Seiji Ogo
Hong Chen
Marilyn M. Olmstead
Richard H. Fish
10.1021/om950681k.s001
https://acs.figshare.com/articles/journal_contribution/Aqueous_Organometallic_Chemistry_2_sup_1_sup_H_NMR_Spectroscopic_Synthetic_and_Structural_Study_of_the_Chemo-_and_Diastereoselective_Reactions_of_Cp_Rh_H_sub_2_sub_O_sub_3_sub_sup_2_sup_with_Nitrogen_Ligands_as_a_Function_of_pH/3776391
The reactions of a new Cp*Rh aqua synthon,
[Cp*Rh(H<sub>2</sub>O)<sub>3</sub>]<sup>2+</sup>
(<b>1</b>), at acidic pH values
(2−6) with aniline (<b>2</b>), pyridine (<b>3</b>), and
l-phenylalanine (<b>4</b>) have provided interesting
chemo-
and diastereoselectivities as studied by <sup>1</sup>H NMR, FAB/MS,
and single-crystal X-ray
crystallography. The reaction of <b>2</b> and aqua complex
<b>1</b>, at pH values from 4 to 6,
quantitatively provided
[Cp*Rh(η<sup>6</sup>-aniline)]<sup>2+</sup>
(<b>5</b>); the structure of <b>5</b> was
unequivocally
determined by a single-crystal X-ray analysis, which also showed an
approximate 25% η<sup>5</sup>
component. Compound <b>3</b> reacted with <b>1</b>, at pH
2−6, to selectively provide
[Cp*Rh(η<sup>1</sup>-pyridine)<i><sub>n</sub></i>(H<sub>2</sub>O)<sub>3</sub><sub>-</sub><i><sub>n</sub></i>]<sup>2+</sup>
(<i>n</i> = 1−3) complexes <b>6a</b><b>−</b><b>c
</b>as a function of pH. Surprisingly, complex
<b>1</b> reacted with <b>4</b>, from pH 4 to 6, to provide only
one diastereomer of the known cyclic trimer
[(Cp*Rh)(μ-η<sup>1</sup>-(<i>OCO</i>):η<sup>2</sup>-(<i>N</i>,<i>OCO</i>)-l-
phenylalanine)]<sub>3</sub><sup>3+</sup> (<b>7</b>;
<i>S</i><sub>C</sub>,<i>S</i><sub>C</sub>,<i>S</i><sub>C</sub>,<i>S</i><sub>Rh</sub>,<i>S</i><sub>Rh</sub>,<i>S</i><sub>Rh</sub>),
an example
of a <i>one</i>-<i>step</i>, highly diastereoselective reaction
in H<sub>2</sub>O.
1996-04-16 00:00:00
2. 1 H NMR Spectroscopic
FAB
OCO
Aqueous Organometallic Chemistry
1 H NMR
pH
Cp
H 2 O
S Rh
S C