Chem. Mater. 1993,5, 1595-1597
A Square-Pyramidal Tetrahedral Vanadium Phosphate Framework Solid Incorporating Propanediammonium Dications. The Structural Characterization of
(HsNCH2CH2CH2NHs)K[(VO)s(P04)31 Victoria So homonian,+ &in Chen,+ Robert C. l! aushalter,*J and Jon Zubieta'vt
Department of Chemistry, Syracuse University Syracuse, New York 13244 NEC Research Institute, 4 Independence Way Princeton, New Jersey 08540 Received April 7,1993 Revised Manuscript Received August 16, 1993 The self-assembly of molecular precursors into one-, two-, or three-dimensional solids is an area of supramolecular chemistry which has generated significant contemporary interest.lJ While organic materials capable of predictable self-organizationinto ordered arrays a t low temperature have been described? the corresponding inorganic chemistry remains largely undeveloped due to the lack of suitable sdluble precursors. Despite the general lack of soluble molecular inorganic compounds which provide rational synthetic pathwaysto crystallineinorganic solids, it has been abundantly demonstrated that the techniques of "chimie douce? may be exploited in the lowtemperature preparation of open-framework, metastable materials using simple inorganicstarting materials! Most specifically, hydrothermal synthesis5 has provided a convenient route to microporous tetrahedral framework solids,such as zeolites and aluminophosphates,6and more recently has been employed in the preparation of microporous, octahedral-tetrahedral molybdenum phosphate network^.^ Since these molybdophosphate phases represent a first step toward solid materials combining the shape selective absorptivity of a zeolite with the thermal stability and reactivity of a catalytically active metal oxide, we have sought to extend this approach to the vanadium oxide phosphate (V-P-O)system which is notable for ita catalytic importance819and for the unusual structural variability associated with networks of connected vanadium and phosphorus p01yhedra.l~'~The objective of synthesizing Syracuse University. NEC Reseclrch Institute. (1)See, for example: (a) Copp, S.B.; Subramanian, S.;Zaworotko, M. J. J. Am. Chem. Sot. 1992,114,8719.(b) Garcia-Tellado, F.; Geib, S.J.; Goewami, S.; Hamilton, A. D. J. Am. Chem. SOC.1991,113,9265. (c) Zhao, X.;Chang, Y.-L.; Fowler, F. W.; Lauher, J. W. J. Am. Chem. SOC. 1990,112,6627.(d) Etter, M. C. Acc. Chem. Res. 1990,23,120. (2)Mallouk, T. E.; Lee, H. J. Chem. Educ. 1990,67,829. (3)Lindsey, J. S.New. J. Chem. 1991,15,153. (4) (a) Figlarz, M. Chim. Scr. 1988,28,3. (b) Rouxel, J. Chim. Scr. 1988,28,33. (c) Livage, J. Chim. Scr. 1988,28,9. (5)Rabenau, A. Angew. Chem., Znt. Ed. Engl. 1985,24,1026. (6) (a) Barrer, R. M. Hydrothermal Chemistry of Zeolites; Academic Press: New York, 1982. (b) Breck, D. W. Zeolite Molecular Sieues; Krieger: Malabar, FL, 1974. (c) Szostak,R. Molecular Sieves: Principles of Synthesis and Identification; Van Noetrand Reinhold New York, 1989. (d) Occelli, M. L.; Robson, H. E. Zeolite Synthesis; American Chemical Society Washington, DG 1989. (7)Haushalter, R. C.; Mundi, L. A. Chem. Mater. 1992,4,31. (8)Centi, G.; Trifiro, F.; Ebner, J. R.; Franchetti, V. M. Chem. Rev. 1988,88,55. (9)Hodnett, B. Catal. Reu. Sci. Eng. 1985,27,373. (10) Huan, G.; Jo son,J. W.; Jacobson, A. J.; Corcoran, Jr., E. W.; Goehom, D. P. J.Solid. State Chem. l991,93,514andreferences therein. t
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0897-4156/93/2805-1595$04.00l0
1595
V-P-O framework solids which encapsulate organic guest molecules so as to provide large cavities has been realized by the recent synthesis of the chiral solid [(CH&NH& K~[V~~0~~(H~0)~(OH)~(PO~)~l~4H~0,18 The importance of hydrophobic/hydrophilic interactions in the synthesis of this material is evident in the segrqation of more polar and less polar cavitieswithin the framework. By exploiting such hydrophobic/hydrophilic partitioning and by introducing low-valentvanadium sites into the V-P-O networks to reduce framework polarity, a material of significant cavity diameter, (H~NCHZCHZNH~)~(H~NCH~CH~NHZ)[V(H~0)~(VO)~(OH)~(HPO~)~(PO~)~l~2H~O, was subsequently prepared.lg Since the nature of the organic template is crucial in the fashioning of the V-P-0 framework geometry, we have sought to design additional examples of V-P-0 network structures by introducing more complex organic cations. Since the interior of the V-P-0 framework structure must be highly polar, attention was focused on small, highly charged organic cations such as propanediammonium (2+), which has been successfully incorporated into the framework of (HsNCH2CH2CH2NH3)K[(V0)3(P04)al(1). The preparation and properties of 1 are described in this work. The hydrothermal reaction of KVO3,V metal, Hapod, l,&diaminopropane, HC1, and HzO in the optimized mole ratio 3.71:1:10.85.4:12.47:1252 for 40 h at 200 "C and autogenous pressure yields bright green needles of (H3NCH~CHZCHZNH~)K[(VO)~(PO~)J (1) in 65 9% yieldam The infrared spectrum of 1 exhibits bands in the 9 W 960-cm-I range attributed to v(V=Ot) and features between 1000 and 1150 cm-' associated with v(P-0). Thermogravimetricanalysis of 1under N2 eshibita a weight loss of 11.7 9% ,corresponding to the loss the organic cation, at 470 "C. In contrast, when heating is carried out in air, the cation decomposesat 250 "C, suggestingthat the cation cavities are accessible to 02. However, X-ray powderpatterns of 1 heated in air a t 250 "C to constant weight (11)Lii, K. H.; Mao, L. F. J. Solid State Chem. 1992,W,436 and references therein. (12) (a) Patter, A.; Saple, A. R.; Kelken, R. Y. J. Chem. SOC., Chem. Commun. 1991,366and references therein. (b) Montes, C.; Davis, M. E.; Murray, B.; Narayana, M. J. Phys. Chem. 1990,94,6425. (13) ZII~VO(PO~)~: Lii,K. H . ; T d , H. J. J. Solid Chem. 1991,90,291. Cs2VSp4017: Lii, K. H.; Wang, Y. P.; Wang, 5. L. J. Solid State Chem. 1989,80,127.b-KzVgP401,: Lii, K. H.; T d , H. J.; Wang, 5.L. J. Solid State Chem. 1990,87,396.AnVOP207 (A = Cs, Rb): Lii, K. H.; Wang, S. L. J. Solid State Chem. 1989,82,239.AVPzO, (A = Li-Cs): Lii, K. H.; Wang, Y. P.; Chen, Y. B.; Wang, S . L. J. Solid State Chem. 1990,86, 143 and references therein. NaVOPO4: Lii, K. H.; Li, C. H.; Chen, T. M.; Wang, S . L. 2 . Kristallogr. 1991,197,67.RbV&Ol,+r: Lii, K. H.; Lee, C. S.Znorg. Chem. 1990,29,3298. (14)&.~VOPO.-xHzO (A = Na, z = 2.0;A = K, z = L5): Wang, S.L.; Kang, H. Y.; Cheng, C. Y.; Lii, K. H. Znorg. Chem. 1991,30, 3496. K2(VO)zP~Op(OH)~~l.125H~0 Lii, K. H.; Tmi, H. J. Znorg. Chem. 1991, 30,446. K2(VO)a(HPO& Lii, K. H.; Tsai, H. J. J. Solid State Chem. 1991,91,331. (15)LiVOPO4: Lavrov, A. V.; Nikolaev, V. P.; Sadikov, G. G.; PoraiKoshita, M. A. Sou. Phys. Dokl. (Engl. Tram.)1982,27,880. (16)NH,(VO)(HP04): Amoroe, P.; LeBail, A. J. Solid Chem. 1992, 97. - . , -283. - -. (17) CBZV(PO~)(HPO~)~.HZO and CazV(P04)(PzO,): Lii, K. H.; Wen, N. S.; Su, C. C.; Chen, B. R. Znorg. Chem. 1992,31,439. CssV&sOa: Lavrov, A. V.; Nikolaev, V. P.; Sadikov, G. G.; Ya, M. Sou. Phys. Dokl. (Engl. Tram.)1981,26,631. CsV2PlO16: Klinert, B.; Janaen, M. 2.2. Anorg. Allg. Chem. 1988,567,87.Na,9V$aO12: Delmar, C.; Olazcuaga, R.; Cherkaoui, F.; Brochu, R.; LeFlem, G. C.R. Seances Acad. Sci., Ser. C 1978,287,169. (18)Soghomonian, V.; Chen, Q.; Haushalter, R. C.; Zubieta, J.; O'Connor, C. J. Science 1993,259,1596. (19)Soghomonian,V.; Chen,Q.; Haushalter,R. C.; Zubieta, J. Angew. Chem., Znt. Ed. Engl., in press.
0 1993 American Chemical Society
1596 Chem. Mater., Vol. 5, No.11. I993
Figure 1. Polyhedral representation of the vanadium quarepyramid phosphate tetrahedra framework of I viewed down the [1111 cell diagonal. The ( H ~ N C H Z C H Z C H ~ N cations H ~ ) ~are ~ illustrated as conventional hall and stick models within the framework cavities.
Figure 2. Stacked view of two of the 24-membered [V-O-P0 1 s rings of 12 linked polyhedra which serve an the structural motifof 1. WithinoneringthreevanadylV-Ovectorsaredirected in an endocyclic fashion and three are directed in an exocyclic fashion. Successive layers exhibit staggered V-O vectors, prw ducing a projection onto a plane perpendicular to the tunnel direction with six V-0 vectors directed into the cavity.
details of the structural connectivity patterns adopted by the V-P-0 phases. The fundamental binuclear building blocks aggregate indicated that the framework had collapsed. in such a fashion as to produce rings containing 12 X-ray structural analysisof lZ1revealed a complex three polyhedra: six vanadium square pyramids and six phosdimensional structure with a large cavity occupied by the phorus tetrahedra in the alternating arrangement illusorganic cations as shown in Figure 1. The structure is trated in Figure 2. The vanadyl oxo groups of a given ring constructed from corner-sharing VTvsquare pyramidsand are oriented in an alternating endocycliclexocyclicpattern. phosphate tetrahedra and employs a binuclear {(VO)r As this pattern is reversed in the next ring of the stack, (pz-PO4)2}structural motif. While binuclear structural a projection onto a plane perpendicular to the tunnel axis units constructed fromvanadium ockhedraandphosphate gives the illusion of six vanadyl oxo groups directed toward tetrahedra are a recurrent theme of the structural chemtheinteriorofthecavity. However, thethreeV=Ovectors istry of V-P-0 phasesF2units fashioned exclusively from of the top ring are displaced by 5 A from the staggered vanadium square pyramids and phosphorus tetrahedra V=O vectors of the subsequent ring. This ring motif is are limited to 1 and to a second example of a V-P-0 reminiscent of the rings of eight linked polyhedra enframework incorporating an organic cation, (H3NCH2countered in the structure of (H3NCH2CH2NH3)z(H3C H Z N H ~ ) Z ( H ~ N C H Z C H Z[V(HzO)z(VO)a(OH)rNHZ) NCHzCHzNHz)[V(HzO)z(VO)g(OH)~(HPO~),(HPO~)~(PO~)~~.ZH This Z Oobservation .*~ reinforces the (PO4)4].2H20 and illustrates the role of the larger organic crucial role of the organic template in fine-tuning the template of 1 in dictating ring expansion. Adjacent rings are fused through bridging phosphate groups to produce (20) S y n t h e a i a o f C I I H , z N ~ , ~ ~ V ~AmixtureofKVG,vanadium (l): metal (-325 mesh), HsPO, (85%). 1.3-diaminapropane 1 HCI. and HIO a network of parallel tunnels in which a given ring shares in the male ratio 3.21:1:10.8:5.412.47:1252 was heated in a Parr sad structural elements with six adjacent rings as shown in digestion bomb (23-mL capacity, 30% fill volume) for 40 h a t 200 'C and Figure 1. eutogenauepreaaure. Greenneedlesofi~reisolstedin65% yieldalong with dark blue crystals of B material identified as [HsNCH&H2CHr The connectivity of the covalently bonded vanadium (2) which is currently under investigation. NHaI LV~Os(H~O)~(OH)~(PO,)II phosphate framework generates distinct channels which Anal. Caled for CsH12N,0,aKPsVs(I): C. 5.99; H. 2.W. Found C, 5.87; contain the (H3NCH2CH2CH2NH3)2+ and K+cations. The H, 2.13. The reaction conditions were optimized over a range of reachnt ~~ atoiehiometriea. In contmt to the syntheses of I ( C H S ) ~ N H ~ I K [ V ~ ~ O larger tunnels run parallel to [ l l l ] and contain the large ( H , O ) ~ ( O H ) , ( P O J I I . ~and H ~ ~(H~NCH&H$NH~)~(HSNCH~CH,NH~)(H3NCH2CH2CH2NH3)2+cations. It is noteworthy that ~ V ~ H ~ O ~ ~ ~ V O ~ ~ ~ O H ~ ~ ~ H P the O , preparation ~ , ~ P O , ~of, l1~does 2 Hnot ~O, require the presence of an organophosphonate reagent. While the role the less polar organic cations occupy cavities bordered by of such reagente in the preparations of such aolids remains obscure. the vanadyl groups, while the K+ cations lie in more polar emeqing chemistry ofthe molecular dustem of the VIOIRPOP swtem"" regions of the structure in two distinct tunnel types, as does suggest. however, that oligomeric intermediates are forged which serve 8 8 repositories of V(IV). illustrated in Figure 3. We have noted previously that for (21) CSHI~N~OIIKPSVS (I): triclinic space group Pi,a = 9.047(2) A, both Mo-P-07 and V-P-018 phases the nonpolar organic b = 9.747(2) A, e = 10.288(2) A. 01 = 109.68(3)', B = 101.78(3)", 7 = cations were associated with the less polar molybdenyl 98.11(3)'. V=814.3(4) A3.Z=2.D-=2.451gcmJ. Structuresolution and refinement based on 2826 reflectionsmth Io 2 3 d b ) (3738 collected; ( M d )and vanadyl (V=O)groups, respectively, while Mo Ka, h = 0.110 13 A) converged at a conventional discrepancy factor the inorganic cations are in proximity to the hydrophilic " mm (22) (a) Villeneuve. G.; Siah, K. S.; Amoroa, P.; Casan-Paator, N.; phosphate regions of the framework. Such segregation of Beltran-Porter. D. Chem. Mater. 1992, 4, 108. (h) Betran-Porter, D.; polar and nonpolar enclosures in M-P-0 framework Amoroa,P.; Ibana,R.;Martinez,E.;Beltran-Porte~,A.; LeBai1.A.: Ferey, reflects hydrophobic/hydrophilic interactions which proG.: Villeneuve. G.Solid State Ionic8 1989. 3W33.57. (23) Hum. G. H.; Jacobson. A. J.; Day, V. W. Ansew. Chem..Int, Ed. vide an important dynamic in the crystallization of mixed Engf. 1991,30. 422. organicinorganic solid frameworks. (24) Hum, G. H.; Day, V. W.; Jacobson,A. J.; &horn, D.P. J. Am. Chsm. Soe. 1991, 113, 3188. The preparation of 1 expands the number of examples (25) Chen, Q;Zubieta. J. Angew. Chem., Int.Ed.Ewl. 1993,32,261. (26) Sslta, J.; Chang, Y.;Chen, 8.; Zubista, J., unpublished tesesults. of vanadium phosphate phases incorporating organic Y.
Communications
Chem. Mater., Vol. 5, No. 11, 1993 1597 and the presence of reactive transition-metal centers embedded in the cavity walls in an appropriate geometric juxtaposition for molecular recognition. In this respect, the presence of the coordinatively unsaturated pyramidal vanadium(1V) centers provides a primitive realization of this goal. While the broad objective of preparing 3-D framework solids with incipient microporosity to provide sites for shape-selective catalytic reactions at internal d-block centers has been achieved, the problem of organic cation removal has yet to be solved. The windows that the cavities employ to communicate with the outside environment are too small to allow facile passage to useful organic substrates. Although the synthetic conditions required to overcome this difficulty remain obscure, it may be that the interior surfaces of VIP10 solids are too polar to incorporate organic cations of significant size; thus far only relatively small, highly charged ammonium cations have been successfully introduced. One strategy which we are currently pursuing is the preparation of mixed phosphatelorganophosphonatevanadium oxide frameworks which if successful should decrease the polarity of the framework and allow incorporation of a variety of organic cations.
Figure 3. (a, top) View of the structure of 1 down the crystallographicc axis,showingonetype of K+cavity. (b,bottom) A view down the a axial direction showingthe second type of K+ environment). templates and suggests that judicious choice of organic guests may afford an entry to the design of solid microporous phases combining size selectivity of substrates
Acknowledgment. The work at Syracuse University was supported by NSF Grant CHE 9119910. Supplementary Material Available: Tables of experimental details of structure solution, atomic positional parameters and isotropictemperature factors, bond lengths and bond angles, anisotropic temperature factors, and calculated hydrogen atom positions (7 pages); table of structure factor values (9 pages). Ordering information is given on any current masthead page.
