Premium
Hydrothermal Synthesis, Structure Characterization, Catalytic Property of Four Inorganic‐Organic Hybrid Phosphomolybdates
Author(s) -
Chen Qi,
Cui Yan,
Sun Qi,
Pan Wenjun,
Chen Qiang,
Xu Yan
Publication year - 2009
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200801336
Subject(s) - triethylenetetramine , piperazine , protonation , chemistry , dimer , crystal structure , crystallography , medicinal chemistry , polyoxometalate , hydrothermal synthesis , diethanolamine , catalysis , amine gas treating , stereochemistry , inorganic chemistry , ion , hydrothermal circulation , organic chemistry , seismology , geology
Abstract Four new inorganic‐organic hybrid polyoxometalate compounds based on the {Mo 6 P 4 } unit have been hydrothermally synthesized from the reaction of MoO 3 , Co(CH 3 COO) 2 · 4H 2 O, triethylenetetramine (TETA) and 50 % phosphorus acid, and characterized by IR, TG, ICP and single‐crystal X‐ray diffraction. Compound 1 (H 4 TETA) 2 [(Co II TREN) 2 Co II Mo V 12 P 8 O 52 (OH) 10 ] · 4H 2 O [TREN = tris(2‐aminoethyl)amine], which is obtained at pH = 8.9, represents a {Mo 6 P 4 } unit supported transition metal complex, in which the Co II atom is pentacoordinate by four nitrogen atoms from TREN and one oxygen atom from PO 4 tetrahedron, and the other Co II atom joins two {Mo 6 P 4 } units together to form a dimer by sharing six μ 3 ‐O atoms. Compound 2 (H 4 TETA) 2 (C 6 H 18 N 3 ) 2 [Co II Mo V 12 P 8 O 54 (OH) 8 ] · 5H 2 O [C 6 H 15 N 3 = N ‐(2‐aminoethyl)piperazine] obtained at pH = 6.4 shows a dimer anion [Co II Mo V 12 P 8 O 54 (OH) 8 ] 14– , two fully protonated TETA and two protonated N ‐(2‐ A minoethyl)piperazine. Compounds 3 [H 4 TREN] 4 [Co II Mo V 12 P 8 O 56 (OH) 6 ] · 4H 2 O and 4 [H 4 TETA] 2 [Co II Mo V 12 P 8 O 48 (OH) 14 ] · 4H 2 O obtained from lower pH conditions (4.5 for 3 and 3.1 for 4 ) exhibit the same dimer anion as compound 2 only different cations. As the secondary building unit, the discrete dimer anions in compound 1 – 4 and the TETA (or its derivatives) construct 3D structures by hydrogen bonding interaction. The guest water molecules are filled in the channels, and also involved in the hydrogen bonding with oxygen atoms from inorganic‐organic hybrid framework, which makes the structures more stable. The catalytic properties of the four compounds are also tested in the styrene oxidation with H 2 O 2 .