Characterization of organically pillared zirconium phosphates

Wan, Ben‐Zu; Anthony, R.G.; Peng, Guang Zhi; Clearfield, Abraham

doi:10.1016/0021-9517(86)90224-1

Cited by 59 publications

(5 citation statements)

References 4 publications

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“…The narrow galleries of α-ZrP may protect the bound proteins from microbial degradation. α-ZrP provides a large surface area upon exfoliation of the lamellae, and α-ZrP can present anionic surfaces (up to one negative charge per phosphate) for binding. α-ZrP binds metal ions, alkylammonium salts, metal complexes, organic cations, and proteins in the interlayer regions .…”

Section: Introductionmentioning

confidence: 99%

Proteins Immobilized at the Galleries of Layered α-Zirconium Phosphate: Structure and Activity Studies

2000

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Facile immobilization of myoglobin (Mb), lysozyme (Lys), hemoglobin (Hb), chymotrypsin (CT), and glucose oxidase (GO) at the interlayer regions of layered α-zirconium phosphate (α-ZrP) under ambient conditions (pH 7.2, room temperature) is described. The proteins retain their structure and activity after immobilization. The interlayer spacings of α-ZrP (observed in powder XRD experiments) increased from 7.6 Å (for α-ZrP) to 53, 47, 66, 62, and 108 Å when Mb, Lys, Hb, CT, and GO are bound to the matrix, respectively. These XRD data strongly suggest intercalation of the proteins in the galleries. The binding constants of the above proteins with α-ZrP, estimated from the centrifugation method, are in the range of 104−106 M-1. The α, β, and the soret absorption bands of Mb/Hb immobilized on α-ZrP were essentially superimposable with those of the native proteins in solution. The FTIR spectra of the enzyme−α-ZrP composites, measured with an attenuated total reflectance accessory, show that the amide I and amide II bands of the immobilized proteins correlate well with those of the free proteins. The circular dichroism (CD) spectra of immobilized proteins, similarly, are quite similar to those of the corresponding native proteins. These various spectral investigations are consistent with high affinity binding of the proteins to α-ZrP with considerable retention of protein structure. Activities of the immobilized proteins are investigated for comparison with those of the proteins in solution. The hydrolytic activity of immobilized lysozyme is essentially the same as that of the free protein. CT and GO showed small but reproducible increases in their activities upon immobilization. The enzymatic activity parameters, K m and Vmax, observed for the immobilized Mb, lysozyme, and GO are comparable to those of the native proteins. The peroxidase activity of Mb/Hb depended on the substrate structure. Activities are higher for the immobilized Mb when p-methoxyphenol, phenol, and m-aminophenol are used as the substrates. The activities have been lower, on the other hand, when aniline, o-cresol, and o-aminophenol are used as the substrates. In general, the ratio of the specific activities of immobilized Mb to those of free Mb roughly increases with increased substrate oxidation potential. The interlayer spacings observed for the protein−α-ZrP composites show a strong correlation with the average size of the protein, and this method may be useful for the determination of protein size. The binding affinities of the proteins correlate with their respective pI values, with the exception of Hb, suggesting the role of electrostatic interactions in the binding process. The average area occupied per protein molecule is larger than the average area of cross section of the proteins, and the area occupied correlates with the reciprocal of the corresponding binding constants. These studies indicate that the hydrophilic character of the matrix and its surface charge are important attributes that influence the bound protein behavior. Enhanced ac...

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Section: Introductionmentioning

confidence: 99%

Proteins Immobilized at the Galleries of Layered α-Zirconium Phosphate: Structure and Activity Studies

2000

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“…The increased activity in the field of metal phosphonate chemistry is primarily due to their potential application in the areas of sorption and ion exchange, catalysis, , sensors, , and nonlinear optics. ,, Originally work in this area was directed toward the study of the layered compounds of four-valent compounds largely due to their high stability. , Subsequent studies revealed that the quadrivalent metal ions are also capable of forming new structural types apart from the conventional layered structures . Recent studies have shown that a variety of other metal ions including divalent and trivalent metals, alkaline earth metals, uranyl ions, etc.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and X-ray Powder Structures of Two Lamellar Copper Arylenebis(phosphonates)

et al. 1996

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Reaction of copper salts with 1,4-phenylenebis(phosphonic acid) yielded a conventional layered compound, Cu(2)[(O(3)PC(6)H(4)PO(3))(H(2)O)(2)], while a similar reaction with 4,4'-biphenylenebis(phosphonic acid) resulted in a new lamellar structure with composition Cu[HO(3)P(C(6)H(4))(2)PO(3)H]. The structures of these compounds were solved ab initio by using X-ray powder diffraction data. The crystals of the phenylenebis(phosphonate) compound are monoclinic, space group C2/c, with a = 18.8892(4) Å, b = 7.6222(2) Å, c = 7.4641(2) Å, beta = 90.402(2) degrees, and Z = 4. The layer structure in this case is similar to that in copper phenylphosphonate, Cu[O(3)PC(6)H(5)]. The metal atoms display a distorted square pyramidal geometry where four of the coordination sites are occupied by the phosphonate oxygens. The remaining site is filled by an oxygen atom of the water molecule. Adjacent metal-O(3)PC layers are covalently pillared by the phenyl group of the phosphonates to create a 3-dimensional structure. Cu[HO(3)P(C(6)H(4))(2)PO(3)H] is triclinic, space group P&onemacr;, with a = 4.856(2) Å, b = 14.225(5) Å, c = 4.788(2) Å, alpha = 97.85(1) degrees, beta = 110.14(1) degrees, gamma = 89.38(1) degrees, and Z = 1. The structure in this case, ideally consists of linear chains of copper atoms. The copper atoms are bridged by centrosymmetrically related phosphonate groups utilizing two of their oxygen atoms. This binding mode leads to square planar geometry for the copper atoms. The third oxygen atom of the phosphonate is protonated and is involved in linking adjacent linear chains through hydrogen bonds. At the same time, these hydroxyl oxygens interact weakly (Cu-O = 3.14 Å) with the copper atoms of the adjacent chain. Considering these long Cu-O interactions, the geometry of the copper atom may be described as distorted square bipyramidal. As in the phenylphosphonate structure, the biphenyl groups covalently link the Cu-O(3)PC networks in the perpendicular direction.

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“…Early work on metal phosphonate chemistry was centered on the layered compounds of group 4 and 14 elements largely because of their similarity to the inorganic phosphates of these metals and their great stability. , Tetravalent metal phosphonates M(O 3 PR) 2 , have octahedrally coordinated metal atoms, where all the coordination sites are occupied by the phosphonate oxygens. The metal phosphate networks, which constitute the layers, are separated by the organic portion of the phosphonate group. − Studies from this and other groups have now shown that a variety of other metal ions can form similar layered compounds. − In addition, some of these compounds have been shown to form a variety of new structural types, − including porous structures. − The metal phosphonate compounds have attracted substantial research interest primarily because of their potential application in the areas of sorption and ion exchange, catalysis, , sensors, , and nonlinear optics. ,, …”

Section: Introductionmentioning

confidence: 99%

Synthesis and X-ray Powder Structures of Covalently Pillared Lamellar Zinc Bis(phosphonates)

et al. 1996

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Two new lamellar metal phosphonates, zinc phenylenebis(phosphonate), Zn2[(O3PC6H4PO3)(H2O)2] (1), and zinc biphenylylenebis(phosphonate), Zn[HO3P(C6H4)2PO3H] (2), have been synthesized. The structures of these compounds were solved ab initio from X-ray powder diffraction data and refined by Rietveld methods. Compound 1 is orthorhombic: space group Pnnm, a = 19.2991(6) Å, b = 4.8232(2) Å, c = 5.6545(2) Å, and Z = 2. The structure is layered, and its layer arrangement is similar to that in zinc phenylphosphonate. The zinc atoms are octahedrally coordinated. Two of the oxygens of the phosphonate group are involved in chelation and bridging the metal atoms. The third oxygen binds to only one metal atom. The sixth coordination site is occupied by a water molecule. The adjacent layers are bridged by the phenylene group of the bis(phosphonate). Compound 2 is triclinic: space group P1̄, a = 9.5097(3) Å, b = 5.0074(2) Å, c = 14.2109(4) Å, α = 92.797(3)°, β = 99.725(3)°, γ = 92.003(3)°, and Z = 2. In this case the metal atoms are tetrahedrally coordinated by four oxygens, two from each of the phosphonate groups of the bis(phosphonate). The third oxygen of the phosphonate group is protonated and is not involved in metal binding. The structure consists of double chains with alternating Zn and P atoms connected to each other by phosphonate bridges. These double chains run along the b axis and are linked to similar chains along the a direction through hydrogen bonds involving P−OH groups. This arrangement leads to loosely bound metal−CPO3 networks in the ab plane which are bridged by the biphenylylene groups along the c axis. Thus in a broad sense this compound may also be considered as layered.

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Characterization of organically pillared zirconium phosphates

Cited by 59 publications

References 4 publications

Proteins Immobilized at the Galleries of Layered α-Zirconium Phosphate: Structure and Activity Studies

Proteins Immobilized at the Galleries of Layered α-Zirconium Phosphate: Structure and Activity Studies

Synthesis and X-ray Powder Structures of Two Lamellar Copper Arylenebis(phosphonates)

Synthesis and X-ray Powder Structures of Covalently Pillared Lamellar Zinc Bis(phosphonates)

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