Hybrid Organic-Inorganic Polyoxometalates Functionalized by Diorganotin Groups by Firasat Hussain A thesis submitted in partial ful¯llment of the requirements for the degree of Doctor of Philosophy Approved, Thesis Committee: Prof. Ulrich Kortz (Mentor), IUB Prof. Ryan M Richards, IUB Dr. Michael H Dickman, IUB Prof. Michael T Pope Georgetown University, U.S.A. Prof. Emmanuel Cadot Universit¶ede Versailles, France Date of defense: 19 May 2006 School of Engineering and Science To my beloved parents Abstract Polyoxometalates (POMs) are a well-known class of inorganic metal-oxygen clusters with an unmatched structural variety combined with a multitude of properties. The search for novel POMs is predominantly driven by exciting catalytic, medicinal, material science and bioscience applications. However, the mechanism of action of most polyoxoanions is not selective towards a speci¯c target. In order to improve selectivity it appears highly desirable to attach organic functionalities covalently to the surface of polyoxoanions. The hydrolytic stability of the Sn-C bond enables the synthesis of a novel class of polyoxoanions via attachment of organometallic functionalities based on Sn(IV) to the surface of lacunary polyoxoanion precursors. III III By reacting (CH3)2SnCl2 with Na9(®-XW9O33) (X = As , Sb ) in aqueous acidic medium leads to the formation of 2-D solid-state structures with inorganic and organic surface, which are rare examples of discrete polyoxoanions. (CsNa4f(Sn(CH3)2)3O(H2O)4 (¯-AsW9O33)g¢5H2O)1 (CsNa-1) and the isostructural (CsNa4[(Sn(CH3)2)3O(H2O)4( ¯-SbW9O33)]¢5H2O)1 (CsNa-2)It has been synthesized and characterized by multinu- clear NMR spectroscopy, FTIR spectroscopy and elemental analysis. They crystallizes in the orthorhombic system, space group P na21, with identical unit cell parameters a = 26.118(2) A,º b = 16.064(1) A,º c = 13.776(1) A,º and Z = 1. Multinuclear NMR (183W, 119Sn, 13C, 1H) showed that CsNa-1 and CsNa-2 decomposes in solution leading to the 3¡ III III monomeric species [fSn(CH3)2(H2O)2g3(¯-XW9O33)] (X = As (1), Sb (2). Polyan- ions 1 and 2 consist of a (¯-XW9O33) fragment which is stabilized by three dimethyltin fragments. The three dimethyltin groups of 1 and 2 are grafted onto the polyanion via two Sn-O(W) bonds involving the terminal O atoms on the side of the hetero atom lone pair. This polyanion has a nominal Cs symmetry. i 22¡ Reacting (CH3)2SnCl2 with the superlacunary polyanion [H2P4W24O94] resulted in 36¡ a dimeric hybrid organic-inorganic polyanion, [fSn(CH3)2g4(H2P4W24O94)2] (3).It has been characterized by multinuclear NMR spectroscopy, FTIR spectroscopy and elemen- tal analysis. Single-crystal X-ray analysis of K17Li19[fSn(CH3)2g4(H2P4W24O94)2]¢51H2O showed that it crystallizes in the tetragonal system, space group P 42/nmc, a = b = 21.5112(17) A,º c = 27.171(3) A,º Z = 2. Polyanion 3 is composed of two (H2P4W24O94) fragments that are linked by four equivalent diorganotin groups. The unprecedented as- sembly 3 has D2d symmetry and contains a hydrophobic pocket at its center. The trimeric, hybrid organic-inorganic tungstophophate(V) 18¡ [fSn(CH3)2(OH)g3(Sn(CH3)2)3fA-PW9O34g3] (4) has been synthesized in acidic medium. It has been characterized by FTIR spectroscopy, elemental analysis and cyclic voltametry. Single-crystal X-ray analysis of the compound showed that it crystallizes in rhombohedral system, space group R 3m, a = b = 29.7445(7) A,º c = 15.5915(7) A,º Z = 3. The polyanion is composed of three (A-®-PW9O34) fragments that are linked by six dimethyltin groups, where the outer three ones are connected by ¹2 ¡ OH bridges leading to a cyclic core which act as a cap leading to a bowl type structure. This arrangement results in a cyclic, trimeric, unprecedented polyanion assembly with C3v symmetry. The tetrameric, hybrid organic-inorganic tungstoarsenate(III) [fSn(CH3)2(H2O)g2 12¡ fSn(CH3)2gAs3(®-AsW9O33)4] (5) has been characterized by multinuclear NMR spec- troscopy, FTIR spectroscopy and elemental analysis. Single-crystal X-ray analysis of the compound showed that it crystallizes in the monoclinic system, space group P 21/c, with a = 22.612(2) A,º b = 19.954(2) A,º c = 41.099(4) A,º Z = 4. Polyanion 5 is composed of four (B-®-AsW9O33) fragments that are linked by three dimethyltin groups and three As(III) atoms resulting in an unprecedented, chiral polyoxoanion assembly with C1 symmetry. V V Interaction of (CH3)2SnCl2 with Na9[A-XW9O34] (X = P , As ) in aqueous acidic medium resulted in the dodecameric, ball-shaped anions [fSn(CH3)2(H2O)g24fSn(CH3)2g12 36¡ V V (A-XW9O34)12] (X = P , As )(6-7). They has been characterized by multinuclear NMR spectroscopy, FTIR spectroscopy, scanning tunneling microscopy and elemental analysis. Both compounds crystallize as mixed cesium-sodium salts and are isomorphous. Single crystal Single-crystal X-ray analysis of the compound showed that it crystallizes in ii the cubic system (space group I m3¹ with a = b = c = 32.7441(4) A,º Z = 2 . The spherical structure of the polyanion is spectacular in terms of geometry and size (diameter of 30 A)º and is unprecedented in polyoxotungstate chemistry. This supermolecular assembly 9¡ V V is composed of 12 trilacunary [A-XW9O34] (X= As ,P ) Keggin fragments which are 2+ 2+ linked by 36 dimethyltin groups [12 inner (CH3)2Sn and 24 outer (CH3)2(H2O)Sn groups] resulting in a polyanion with Th symmetry. The polyanion contains 1000 atoms with a molar mass of around 33000 gmol¡1. The bis-phenyltin substituted lone pair containing tungstoarsenate [(C6H5Sn)2As2W19O67 8¡ (H2O)] (8) has been synthesized and characterized by multinuclear NMR, FTIR spec- troscopy and elemental analysis. Single-crystal X-ray analysis of (NH4)7Na[(C6H5Sn)2As2W19O67(H2O)]¢17.5H2O showed that it crystallizes in the mon- oclinic system, space group P 21/c, with, a = 18.3127(17) A,º b = 24.403(2) A,º c = ± III 22.965(2) A,º ¯= 106.223(2) , and Z = 4. Polyanion 8 consists of two B-®-(As W9O33) 3+ Keggin moieties linked via WO(H2O) fragment and two (SnC6H5) groups leading to a sandwich-type structure with nominal C2v symmetry. The titanium(IV), disubstituted lone pair containing tungstoarsenate 8¡ [(TiOH)2WO(H2O)As2W19O67] (9) has been synthesized and characterized by FTIR spectroscopy and elemental analysis. Single-crystal X-ray analysis was carried out on Cs8[(TiOH)2WO(H2O)As2W19O67]¢10.5H2O which crystallizes in the monoclinic system, space group P 21/m , with a = 12.7764(19)A,º b = 19.425(3) A,º c = 18.149(3) A,º ± III ¯=110.23(3) , and Z = 2. Polyanion (9) consists of two B-®-(As W9O33) Keggin moi- 4+ 4+ eties linked via one [WO(H2O)] fragment and two Ti ions leading to a sandwich-type structure with nominal C2v symmetry. Interaction of solid TiO(SO4) with K14[P2W19O69(OH2)] in an aqueous acidic medium resulted in a novel, trimeric polyoxometalate . The compound has been characterized by FTIR spectroscopy and elemental analysis. Single-crystal X-ray analysis of the com- pound showed that it crystallizes in rhombohedral system, space group R 3m, a = b = 29.7444(7) A,º c = 13.6254(9) A,º Z = 3. The polyanion (10) is composed of three ®- Ti3PW9O34 Keggin fragments that are linked via Ti-O-Ti bridges leading to a trimeric assembly. Interestingly, one of the titanium from each fragment is connected to the phos- iii phate leading to a trimeric-capped type structure with nominal C3v symmetry. 8¡ Interaction of solid TiO(SO4) with [γ-SiW10O36] in an aqueous acidic medium re- 24¡ sulted in a novel, tetrameric polyoxometalate [¯-Ti2SiW10O39]4] (11).It has been char- acterized by multinuclear NMR spectroscopy, FTIR spectroscopy and elemental analysis. Single-crystal X-ray analysis of the compound showed that it crystallizes in monoclinic system, space group P 21/n, a = 12.5188(13) A,º b = 18.864(2) A,º c = 41.075(4) A,º ¯ ± = 97.450(2) Z = 2. The polyanion is composed of four ¯-Ti2SiW10O39 Keggin frag- ments that are linked via Ti-O-Ti bridges leading to a cyclic assembly. The solid-state structure of K24[(¯-Ti2SiW10O39)4]¢50H2O shows face-by-face self assembled polyanions (K-11) along the crystallographic `a' axis, which leads to a nanotube-like arrangement. 12¡ The cadmium(II)-substituted tungstoarsenate [Cd4Cl2(B-®-AsW9O34)2] (12) has been synthesized and characterized in the solid state by XRD, FTIR spectroscopy, ele- mental analysis and 183W and 111Cd NMR spectroscopy. Single crystal X-ray analysis of Cs4K3Na5[Cd4Cl2(B-®-AsW9O34)2]¢20H2O (CsKNa-12), shows that it crystallizes in the monoclinic system, space group P 21/n, with a = 13.1402(12) A,º b = 19.0642(17) A,º c = 17.5666(15) A,º ¯ = 90.274(2)± and Z = 2. Polyanion (9) consists of two lacunary 10¡ [B-®-AsW9O34] Keggin moieties linked via a rhomb like (Cd4O14Cl2) cluster leading to a sandwich-type structure. Interestingly, the two external Cd atoms each have a terminal 10¡ Cl ligand, but the derivative have terminal water ligands, [Cd4(H2O)2(B-®-AsW9O34)2] (13), which has been proved by 183W and 111Cd NMR spectroscopy. 11¡ The indium(III)-substituted polyanions [In3Cl2(B-®-PW9O34)2] (14), [In3Cl2(P2W15 17¡ 4¡ 6¡ O56)2] (15), [In4(H2O)10( ¯-AsW9O32OH)2] (16) and [In4(H2O)10(¯-SbW9O33)2] (17) have been synthesized and characterized in the solid state by FTIR spectroscopy and elemental analysis and 183W-NMR. Single-crystal X-ray analysis showed that D,L- (NH4)11[In3Cl2(B-®-PW9O34)2]¢16H2O (NH4-14) showed that it crystallizes in the mon- oclinic system, space group P 21/n, with a = 17.5090(10) A,º b = 12.7361(7) A,º c = 18.7955(11) A,º ¯ = 107.3030(10)±, and Z = 2; D,L- (NH4)9Na8[In3Cl2(P2W15O56)2]¢39H2O (NH4Na-15) crystallizes in the triclinic sys- tem, space group P 1,¹ with a = 13.0643(5) A,º b = 14.8901(6) A,º c = 19.8603(8) A,º ® ± ± ± = 92.2920(10) , ¯ = 90.8680(10) , γ = 100.5630(10) , and Z = 1; RbNa3[In4(H2O)10(¯- iv AsW9O32OH)2]¢36H2O(RbNa-16) crystallizes in the triclinic system, space group P 1,¹ with a = 12.8142(5) A,º b = 12.8672(5) A,º c = 16.1794(7) A,º ® = 91.1370(10) ±, ¯ = ± ± 105.9450(10) , γ = 104.0980(10) and Z = 1; K4Na2[In4(H2O)10(¯-SbW9O33)2]¢30H2O (KNa-17) crystallizes also in the triclinic system, space group P 1,¹ with a = 12.2306(9) A,º b = 12.7622(10) A,º c = 16.1639(12) A,º ® = 73.9890(10)±, ¯ = 76.5550(10)±, γ = 86.2130(10)± and Z = 1.