Pamela J. Hagrman

Organic-inorganic hybrid materials: From 'simple' coordination polymers to organodiamine-templated molybdenum oxides

A blueprint for the design of oxide materials is provided by nature. By borrowing from natures ability to influence inorganic microstructures in biomineralization processes and in the hydrothermal synthesis of complex minerals, a new class of materials in which organic components exert a role in controlling inorganic microstructure is evolving. By employing members of the ever-expanding class of polymeric coordination complex cations, novel molybdenum oxide substructures, such as the one shown, may be prepared.

Solid-State Coordination Chemistry: The Self-Assembly of Microporous Organic–Inorganic Hybrid Frameworks Constructed from Tetrapyridylporphyrin and Bimetallic Oxide Chains or Oxide Clusters

The hydrothermal reactions of MoO(3), tetrapyridylporphyrin (tpypor), water, and the appropriate M(II) precursor yield the first examples of three-dimensional framework materials constructed from metal oxide and porphyrin subunits. The picture shows a section of [{Fe(tpypor)}(3)Fe(Mo(6)O(19))(2)] small middle dotx H(2)O with the [Fe(8)(tpypor)(6)](8+) building block of the cationic framework and the entrained {Mo(6)O(19)}(2-) cluster.

Organisch-anorganische Hybridmaterialien: von „einfachen” Koordinationspolymeren zu Molybdänoxiden mit Organodiamin-Templaten

Eine Blaupause fur das Design von Oxidmaterialien kann uns die Natur liefern, da sie bei Biomineralisationsprozessen und bei der Hydrothermalsynthese komplexer Mineralien anorganische Mikrostrukturen beeinflussen kann. Eine Anleihe bei dieser Fahigkeit fuhrt zu einer ganz neuen Klasse von Materialien, bei denen organische Komponenten eine Rolle bei der Kontrolle uber die anorganischen Mikrostrukturen spielen. Der Einsatz von Verbindungen aus der bestandig wachsenden Klasse polymerer Komplexkationen ermoglicht die Herstellung von Molybdanoxiden mit neuartigen Substrukturen (siehe das im Bild gezeigte Beispiel).

Molecular manipulation of solid state structure: Influences of organic components on vanadium oxide architectures

Abstract Among the inorganic materials enjoying widespread contemporary interest, the metal oxide based solid phases occupy a prominent position by virtue of their applications to catalysis, sorption, molecular electronics, energy storage, optical materials and ceramics. The diversity of properties associated with these materials reflects the chemical composition, which allows variations in covalency, geometry and oxidation states, and the crystalline architecture, which may provide different pore structures, coordination sites, or juxtapositions of functional groups. Despite such fundamental and practical significance, the design of the structure of such materials remains a challenge in solid state chemistry. While organic materials have been synthesized which self-assemble into ordered arrays at low temperature and which exhibit molecular recognition and biomimetic activity, the ability to synthesize inorganic materials by rational design remains elusive. Small, soluble molecular building blocks with well-defined reaction chemistries which allow their low-temperature assembly into crystalline solid state inorganic materials are not well known. However, the existence of naturally occurring, structurally complex minerals establishes that hydrothermal synthesis can provide a low temperature pathway to produce open-framework and layered metastable structures utilizing inorganic starting materials. Thus, hydrothermal conditions have been used to prepare microporous tetrahedral framework solids that are capable of shape-selective absorption, like zeolites and aluminophosphates, and more recently in the preparation of complex solid arrays of the M/O/PO3−4 and M/O/RPO2−3 systems (M=V and Mo). The hydrothermal technique may be combined with the introduction of organic components which may act as charge compensating groups, space-filling units, structure directing agents, templates, tethers between functional groups, or conventional ligands in the preparation of inorganic/organic composites. In the past decade, this general strategy has been exploited in the evolution of a family of vanadium oxides incorporating structure-directing organic or secondary-metal organic subunits, which are the topic of this review. The synthetic approach to novel vanadium oxide solids occupies the interface between materials science and coordination chemistry. The emerging theme focuses on the association of an organic component, acting as a ligand, tether, or structure directing moiety, with the inorganic framework of the solid to provide unique composites. While some organic components may limit the size of inorganic cluster subunits of a solid by passivating the surface of an aggregate through capping, such ligands may also serve to link inorganic subunits into complex networks. In other cases, the organic subunit, rather than participating as a covalently bound unit of the framework, acts in a structure directing role, producing amphiphilic materials whose structures are determined by hydrophobic–hydrophilic interactions. This latter feature is reminiscent of the factors influencing biomineralization, a field which may prove relevant to the development of new strategies for the controlled synthesis of organized inorganic and organic/inorganic composite materials. These various approaches to the “design” of inorganic solids are discussed and assessed in terms of the new structural types recently observed in the vanadium oxide chemistry.

Polyoxomolybdate clusters and copper–organonitrogen complexes as building blocks for the construction of composite solids

Abstract The influences of ligand coordination modes on the oxide microstructures in the copper molybdate system were investigated. Rigid bridging ligands such as 4,4′-bypyridine (4,4′-bpy) and 2,4,6-tripyridyltriazine (tptz) afford polymeric cationic substructures with Cu(I) which provide scaffoldings for the entrainment and modification of the molybdenum oxide microstructure. These structural influences are manifested in [{Cu(4,4′-bpy)} 2 Mo 2 O 7 ] ( MOXI-45 ) and [{Cu(tptz)} 2 Mo 6 O 19 ] ( MOXI-46 ). In contrast, ligands such as pyridine (py) which do not effect the construction of polymeric substructures provide molecular building blocks which combine with the molybdenum oxide motifs in a less predictable fashion. Thus, [{Cu(py)} 4 Mo 8 O 26 ] ( MOXI-47 ) is constructed from octamolybdate clusters linked by {Cu(py)} +1 fragments into a virtual two-dimensional network. The interplay of ligand geometry and bonding mode and of metal coordination preferences plays an important role in the structure of [{Cu 2 (tpypz)(H 2 O) 2 }Mo 8 O 26 ] ( MOXI-44 ), the unique example of a Cu(II)-containing material, with the binucleating tetrapyridylpyrazine ligand (tpypz) providing the organic building unit. The overall structure reflects the binucleating role of the ligand and the distorted octahedral geometry of the Cu(II) centers. The importance of hydrothermal techniques in effecting the syntheses of such composite materials is also discussed.

The Structural Role of Metal-Organonitrogen Subunits in the Molecular Manipulation of Molybdenum Oxides

Abstract Although solid state metal oxides are of both fundamental and practical interest, the designed synthesis of such materials remains an elusive goal. However, valuable synthetic guidelines may be derived from a consideration of the plethora of Natures remarkable materials which contain composites of molecules or microstructures in which inorganic components coexist with organic components. The presence of organic subunits can profoundly influence the crystallization of the inorganic microstructure, offering a powerful tool for the design of novel materials. In the specific case of molybdenum oxide phases, metal-organoamine molecules, fragments, an even polymeric coordination complex cations may be exploited in the self-assembly of complex hierarchical materials.

Effect of hemoglobin concentration variation on the accuracy and precision of glucose analysis using tissue modulated, noninvasive, in vivo Raman spectroscopy of human blood: a small clinical study

Tissue modulated Raman spectroscopy was used noninvasively to measure blood glucose concentration in people with type I and type II diabetes with HemoCue fingerstick measurements being used as reference. Including all of the 49 measurements, a Clarke error grid analysis of the noninvasive measurements showed that 72% were A range, i.e., clinically accurate, 20% were B range, i.e., clinically benign, with the remaining 8% of measurements being essentially erroneous, i.e., C, D, or E range. Rejection of 11 outliers gave a correlation coefficient of 0.80, a standard deviation of 22 mg/dL with p<0.0001 for N=38 and places all but one of the measurements in the A and B ranges. The distribution of deviations of the noninvasive glucose measurements from the fingerstick glucose measurements is consistent with the suggestion that there are at least two systematic components in addition to the random noise associated with shot noise, charge coupled device spiking, and human factors. One component is consistent with the known variation of fingerstick glucose concentration measurements from laboratory reference measurements made using plasma or whole blood. A weak but significant correlation between the deviations of noninvasive measurements from fingerstick glucose measurements and the test subjects hemoglobin concentration was also observed.

Ligand influences on the structures of copper molybdate chains: hydrothermal synthesis and structural characterizations of [Cu(2,2′-bipyridine)Mo4O13] and [Cu(2,3-bis(2-pyridyl)pyrazine)Mo2O7]

Abstract Through exploitation of hydrothermal synthesis, two new one-dimensional copper(II) molybdate chains containing a bidentate chelating and space filling ligand have been prepared. [Cu(bpy)Mo4O13] (bpy = 2,2′-bipyridine) (1), and [Cu(pyrpyrz)Mo2O7] (pyrpyrz = 2,3-bis(2-pyridyl)pyrazine) (2). The structure of 1 exhibits a one-dimensional chain of edge-and-corner-sharing {MoO6} octahedra, decorated with {Cu(2,2′-bpy)}2+ groups attached through bridging oxo-groups. The structure of 2 consists of an infinite {Mo2O7}2n−n ribbon of edge sharing molybdenum square pyramids and octahedra. The octahedral molybdenum centers are edge sharing to the copper octahedra which in turn corner share to the square pyramidal molybdenum centers. The nitrogen donors of the ligand occupy one axial and one equatorial site of the copper centers.

Synthesis and structure of a high-nuclearity oxomolybdenum(V) complex, [Mo12O28(OC2H5)4(C6H7N)8]

Abstract (PyH)[MoOBr4(H2O)]·2/3PyHBr (PyH+=pyridinium cation, C5H5NH+) yielded upon the solvothermal reaction with ethanol and 4-methylpyridine (4-MePy, C6H7N) a novel oxoethoxomolybdenum(V) cluster, [Mo12O28(OC2H5)4(4-MePy)8] 1. Molybdenum atoms are grouped into six MoV2 pairs linked by single metal–metal bonds. Three crystallographically independent Mo–Mo distances are 2.5578(14), 2.5981(14) and 2.6489(16) A.

A three-dimensional organic–inorganic composite material constructed from copper–triazolate networks linked through vanadium oxide chains: [{Cu3(trz)2}V4O12]

The hydrothermal reaction of a mixture of V2O5, 1,2,4-triazole (trz), Cu(NO3)2·2.5H2O and H2O yields [{Cu3(trz)2}V4O12], a material constructed from one-dimensional {V4O12}n4n– chains linked to undulating {Cu3(trz)2}n4n+ networks.