167 Mn8 malonate IC

167 Mn8 malonate IC - Inorg. Chem. 1996, 35, 6437-6449 6437...

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Tetranuclear and Octanuclear Manganese Carboxylate Clusters: Preparation and Reactivity of (NBu n 4 )[Mn 4 O 2 (O 2 CPh) 9 (H 2 O)] and Synthesis of (NBu n 4 ) 2 [Mn 8 O 4 (O 2 CPh) 12 (Et 2 mal) 2 (H 2 O) 2 ] with a “Linked-Butterfly” Structure Michael W. Wemple, 1a Hui-Lien Tsai, 1b Sheyi Wang, 1a Juan Pablo Claude, 1a William E. Streib, 1a John C. Huffman, 1a David N. Hendrickson,* ,1b and George Christou* ,1a Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405-4001, and Department of Chemistry-0358, University of California at San Diego, La Jolla, California 92093-0358 Recei V ed March 20, 1996 X The reaction of Mn(O 2 CPh) 2 2H 2 O and PhCO 2 H in EtOH/MeCN with NBu n 4 MnO 4 gives (NBu n 4 )[Mn 4 O 2 (O 2 CPh) 9 - (H 2 O)] ( 4 ) in high yield (85 - 95%). Complex 4 crystallizes in monoclinic space group P 2 1 / c with the following unit cell parameters at - 129 ° C: a ) 17.394(3) Å, b ) 19.040(3) Å, c ) 25.660(5) Å, ± ) 103.51(1) ° , V ) 8262.7 Å 3 , Z ) 4; the structure was refined on F to R ( R w ) ) 9.11% (9.26%) using 4590 unique reflections with F > 2.33 σ ( F ). The anion of 4 consists of a [Mn 4 ( μ 3 -O) 2 ] 8 + core with a “butterfly” disposition of four Mn III atoms. In addition to seven bridging PhCO 2 - groups, there is a chelating PhCO 2 - group at one “wingtip” Mn atom and terminal PhCO 2 - and H 2 O groups at the other. Complex 4 is an excellent steppingstone to other [Mn 4 O 2 ]-containing species. Treatment of 4 with 2,2-diethylmalonate (2 equiv) leads to isolation of (NBu n 4 ) 2 [Mn 8 O 4 (O 2 CPh) 12 (Et 2 mal) 2 (H 2 O) 2 ]( 5 ) in 45% yield after recrystallization. Complex 5 is mixed-valent (2Mn II ,6Mn III ) and contains an [Mn 8 O 4 ] 14 + core that consists of two [Mn 4 O 2 ] 7 + (Mn II ,3Mn III ) butterfly units linked together by one of the μ 3 -O 2 - ions in each unit bridging to one of the body Mn atoms in the other unit, and thus converting to μ 4 -O 2 - modes. The Mn II ions are in wingtip positions. The Et 2 mal 2 - groups each bridge two wingtip Mn atoms from different butterfly units, providing additional linkage between the halves of the molecule. Complex 5 4CH 2 Cl 2 crystallizes in monoclinic space group P 2 1 / c with the following unit cell parameters at - 165 ° C: a ) 16.247(5) Å, b ) 27.190(8) Å, c ) 17.715(5) Å, ± ) 113.95(1) ° , V ) 7152.0 Å 3 , Z ) 4; the structure was refined on F to R ( R w ) ) 8.36 (8.61%) using 4133 unique reflections with F > 3 σ ( F ). The reaction of 4 with 2 equiv of bpy or picolinic acid (picH) yields the known complex Mn 4 O 2 (O 2 CPh) 7 (bpy) 2 ( 2 ), containing Mn II ,3Mn III , or (NBu n 4 )[Mn 4 O 2 (O 2 CPh) 7 (pic) 2 6 ), containing 4Mn III . Treatment of 4 with dibenzoylmethane (dbmH, 2 equiv) gives the mono-chelate product (NBu n 4 )[Mn 4 O 2 (O 2 CPh) 8 (dbm)] ( 7 ); ligation of a second chelate group requires treatment of 7 with Na(dbm), which yields (NBu n 4 )[Mn 4 O 2 (O 2 CPh) 7 (dbm) 2 8 ). Complexes 7 and 8 both contain a [Mn 4 O 2 ] 8 + (4Mn III ) butterfly unit. Complex 7 contains chelating dbm - and chelating PhCO 2 - at the two wingtip positions, whereas 8 contains two chelating dbm - groups at these positions, as in 2 and 6 . Complex 7 2CH 2 Cl 2 crystallizes in monoclinic space group P 2 1 with the following unit cell parameters at - 170 ° C: a ) 18.169(3) Å, b ) 19.678(4) Å,
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This note was uploaded on 01/15/2012 for the course CHM 4411 taught by Professor Ohrn during the Spring '08 term at University of Florida.

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167 Mn8 malonate IC - Inorg. Chem. 1996, 35, 6437-6449 6437...

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