Crystal structure of tri(2-methylimidazolium) phosphatopolyoxododecamolybdate, [C4H7N2]3 · PMo12O40

Abstract

C12H21Mo12N6O40P, monoclinic, P121/n1 (no. 14), a = 12.0565(5) A, b = 15.8669(7) A, c = 22.996(1) A, 0 = 98.037(1)°, V = 4355.8 A, Z = 4, Rgt(F) = 0.029, wRref(F ) = 0.070, T = 293 K. Source of material To a 20ml acetonitrile solution ofH3PMo12O40 · 24H2O (1 g)was added 0.1 g methylimidazole in 20 ml acetonitrile with stirring at room temperature. A large quantity of orange yellow precipitate was formed immediately and was filtered off. After the filtrate was kept standing for 3 days, the orange yellow crystals were collected. Discussion The title compound consists of a PMo12O40 anion and three protonated 2-methylimidazole cations. The Keggin PMo12O40 anion is based on a central PO4 tetrahedron surrounded by twelve MoO6 octahedra arranged in four groups of three edge-shared octahedra Mo3O13. These Mo3O13 triplets are linked by the shared corners to each other and the central PO4 tetrahedron. Each of all the Mo atoms in the distorted octahedral environment connects with one terminal oxygen atom (Ot), four doubly bridging oxygen atoms (Ob), one triply bridging oxygen atom (Oc), forming a distortedMoO6 octahedron. TheMo-Modistances are in the range 3.395(1) 3.716(1) A, mean 3.558 A, and the bond angles of O−Mo−O range from 71.6(1) A to 171.8(1) A. The Mo—Ot distances are in the range of 1.662(3) A to 1.680(3) A, average 1.669 A. The Mo—Ob distances range from 1.846(3) A to 1.980(3) A, average 1.914 A. The Mo—Oc distances are in the range 2.419(2) 2.453(3) A, average 2.434 A. The alternating short and longMo—Ob—Mobonds,which result from small displacements of Mo atoms from the mirror planes of the Mo3 triangle in the Keggin anions [1]. The 2-methylimidazolium cations exhibit normal C—CandC—Nbond distances [2,3], which form intermolecular N−H···Ohydrogen bonding to oxygen atoms of the polyanions (d(N···O) = 2.967 3.110A). By virtue of these hydrogen bonds, the adjacent units are connected, stabilizing the whole structure. 432 Z. Kristallogr. NCS 223 (2008) 432-434 / DOI 10.1524/ncrs.2008.0189 © by Oldenbourg Wissenschaftsverlag, Munchen Crystal: orange yellow column, size 0.134 × 0.187 × 0.288 mm Wavelength: Mo K2 radiation (0.71073 A) ': 34.88 cm−1 Diffractometer, scan mode: Bruker SMART APEXII CCD, +/3 2#max: 53.8° N(hkl)measured, N(hkl)unique: 25171, 9449 Criterion for Iobs, N(hkl)gt: Iobs > 2 (Iobs), 7114 N(param)refined: 641 Programs: SHELX-90 [4], SHELXS-97 [5], SHELXL-97 [6], SHELXTL [7] Table 1. Data collection and handling. H(1A) 4e 0.9850 1.0102 0.0521 0.087 H(1B) 4e 0.9333 1.0906 0.0774 0.087 H(1C) 4e 0.8554 1.0255 0.0402 0.087 H(3A) 4e 0.9571 0.8467 0.2168 0.058 H(4A) 4e 0.7962 0.9347 0.2306 0.048 H(5A) 4e 0.7676 0.6219 0.0717 0.094 H(5B) 4e 0.8958 0.6231 0.0663 0.094 H(5C) 4e 0.8554 0.6425 0.1268 0.094 H(7A) 4e 0.7694 0.3349 0.1119 0.087 H(8A) 4e 0.9601 0.3552 0.1578 0.090 H(9A) 4e 0.2983 0.8388 0.4254 0.119 H(9B) 4e 0.3426 0.7563 0.3991 0.119 H(9C) 4e 0.2902 0.7524 0.4577 0.119 H(11A) 4e −0.0574 0.8067 0.3209 0.071 H(12A) 4e −0.0194 0.6589 0.3255 0.094 H(1D) 4e 0.7794 1.0346 0.1464 0.044 H(2A) 4e 1.0238 0.9002 0.1295 0.050 H(3B) 4e 0.7045 0.4730 0.0778 0.081 H(4B) 4e 0.9984 0.5022 0.1505 0.084 H(5D) 4e 0.1705 0.6435 0.3814 0.094 H(6A) 4e 0.1121 0.8747 0.3733 0.062 Table 2. Atomic coordinates and displacement parameters (in A). Atom Site x y z Uiso