
TY  - JOUR
A1  - Kepert, Cameron J. 
A1  - Wei-Min, Lu 
A1  - Junk, Peter C. 
A1  - Skelton, Brian W. 
A1  - White, Allan H. 
T1  - Structural Systematics of Rare Earth Complexes. XI (&#x2018;Maximally&#x2019;) Hydrated Rare Earth(<emph type="6">III</emph>) Trifluoro- and Trichloro-acetates
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1999
VL  - 52
IS  - 6
SP  - 459
EP  - 480
KW  - 
UR  - https://doi.org/10.1071/CH98042 
N2  - Room-temperature single-crystal X-ray structure determinations carried out on &#8216;maximally&#8217; hydrated rare earth(III) trifluoroacetates, Ln(tfa)3.x H2O, crystallized at room temperature, show the Ln = La, Ce adducts to be isomorphous and monoclinic, P 21/c, a &#x2248; 11&#183;9, b &#x2248; 12&#183;8, c &#x2248; 9&#183;8 8 &#197;, &#946; &#x2248; 103&#183;7&#176;, Z = 4; they are trihydrates. The Ln = Pr, Lu (and, implicitly, intermediate Ln) adducts are also monoclinic, P 21/c, Z = 4, and trihydrates, but of a different polymorph, with a &#x2248; 9&#183;2, b 18&#183;8, c &#x2248; 9&#183;8 &#197;, &#946; &#x2248; 114&#176;. For the four determinations, conventional R values on &#124;F&#124; were 0&#183;038, 0&#183;032, 0&#183;036, and 0&#183;034 for No 2952, 4821, 4544, and 4092 independent &#8216;observed&#8217; (I &#62; 3&#963;(I)) diffractometer reflections respectively. The Ln = La, Ce adducts are two-dimensional polymers, the sheets parallel to the bc plane; the other systems are binuclear, the two metal atoms being linked by four bridging carboxylate O-tfa-O&#8242; ligands. In both structural types, the metal atoms are eight-coordinate, but differ in the number of water molecules (2 cf. 3) in the O8 array. Extension of previous studies by single-crystal X-ray methods on the structural characterization of trivalent rare earth trichloroacetates, &#8216;maximally&#8217; hydrated at local ambience, Ln(tca)3.x H2O, suggests the following arrays to be prevalent. The Ln = La adduct is a pentahydrate, monoclinic, P21/c, a 5&#183;636(7), b 22&#183;454(4), c 16&#183;58(1) &#197;, &#946; 90&#183;52(8)&#176;, Z = 4 f.u., R 0&#183;035 for No 4154. The compound is a linear polymer along a, successive nine-coordinate La (separated by a) being linked by three O-tca-O&#8242; bridging ligands at the opposite faces of a tricapped trigonal prismatic array, the equatorial sites being filled by water molecules. The Ln = Ce adduct is a trihydrate, monoclinic, P 21/c, a 10&#183;071(2), b 22&#183;973(2), c 20&#183;222(5) &#197;, b 119&#183;48(2)&#176;, Z= 8 f.u., R 0&#183;050 for No 5019. The array is also linear polymeric, but with successive Ce being linked alternately now by sets of two and then four O-tca-O&#8242; bridging carboxylates along b, the Ln = Ce coordination number being diminished (relative to La) to eight with the coordination of two water molecules to each metal. Ln = Pr, Lu (and, presumptively, intermediate Ln) are dihydrates, triclinic, P 1, a &#x2248; 11&#183;70, b &#x2248; 12&#183;8, c &#x2248; 15&#183;3 &#197;, &#945; &#x2248; 71, &#946; &#x2248; 77&#183;85, &#947; &#x2248; 65&#183;5&#176;, Z = 4 f.u., R 0&#183;056, 0&#183;059 for No 5650, 5398. The array is a linear polymer, similar to that of the Ln = Ce adduct but alongside the bridging acetate pair one of the water molecules now bridges, resulting in a stepped Ln 1 array (along c) rather than a quasi-straight one as is found for the Ln = Ce (and La) adduct. Structure determinations are also recorded for rare earth(III) trichloroacetate ethanol trisolvates, Ln(tca)3.3EtOH. Adducts of Ln = La, Yb (and, implicitly, intermediate Ln) are isomorphous, triclinic, P 1, a &#x2248; 12, b &#x2248; 11&#183;8, c &#x2248; 11&#183;4 &#197;, &#945; &#x2248; 114, &#946; &#x2248; 100, &#947; &#x2248; 104&#176;, Z = 2 f.u., R 0&#183;056, 0&#183;050 for No 3843, 4171. The complexes are centrosymmetric dimers &#91;(EtOH)3(tca-O)Ln(O-tca-O&#8242;)4Ln(O-tca)(HOEt)3&#93;, the two metal atoms being linked by four O-tca-O&#8242; bridging carboxylate groups; the metal atoms are eight-coordinate, the other four sites being occupied by four oxygen atoms from unidentate ethanol and carboxylate moieties. Bis(bis(2-pyridyl)aminium) bis(diaquatetrakis(trichloroacetato)lanthanate(III)), 2(dpaH+) &#91;(H2O)2-(tca-O)(tca-O,O&#8242;)2La(O-tca-O&#8242;)2La(O,O&#8242;-tca)2(O-tca)(OH2)2&#93;2-, is triclinic, P 1, a, 13&#183;901(2), b 13&#183;764(3), c 10&#183;073(2) &#197;, &#945; 104&#183;04(2), &#946; 108&#183;93(2), &#947; 101&#183;50(2)&#176;, Z = 1 binuclear f.u., R 0&#183;045 for No 4999. The anion is binuclear, the two nine-coordinate lanthanum atoms being linked by a pair of bridging O-carboxylate-O&#8242; groups. The other seven sites of the LaO9 array are occupied by a pair of O,O&#8242; -chelating and one O-unidentate carboxylate groups and a pair of water molecules. 
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