Stain Removal from a Pigmented Silicone Maxillofacial Elastomer

The removal of environmental stains from a pigmented maxillofacial elastomer was carried out by solvent extraction under network swelling. Silastic 44210 was pigmented with 11 maxillofacial pigments prior to staining. Samples were stained with lipstick, methylene blue, and disclosing solution. These stains were then removed by solvent extraction with 1,1,1-trichloroethane. Color parameter measurements both before and after staining and after solvent extraction demonstrated the effectiveness of removing these stains by solvent extraction while causing little or no change in the color of the pigmented samples.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68071/2/10.1177_00220345820610081601.pd

Cigarette Staining and Cleaning of a Maxillofacial Silicone

In this study, a maxillofacial silicone elastomer was stained with cigarette smoke. The stain was then removed by solvent extraction using 1,1, 1-trichloroethane. The cigarette smoke produced large color changes in the elastomer as measured from spectrophotometric reflectance curves. The solvent was totally effective in removing the cigarette stain without changing the color of the silicone base.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67997/2/10.1177_00220345830620072101.pd

Tri-, deca- and dodecanuclear Co(III)-pyrazolate metallacycles

Reactions of a Co(III) salt with pyrazoles in the presence of a base have yielded metallacyclic {Co(3)}, {Co(10)} and {Co(12)} species whose structural characterization points to a parallel between analogous carboxylate and pyrazolate motifs

Stain Removal from a Silicone Maxillofacial Elastomer

In this study, environmental stains were removed from maxillofacial elastomers by solvent extraction. Silastic 44210, an RTV silicone with proven color and physical property stability, was stained with lipstick, disclosing solution, and methylene blue. These stains were then removed by solvent extraction with each of four chemically dissimilar solvents, namely: toluene, benzene, 1,1,1-trichloroethane, and n-hexane. An additional series of samples was prepared with 11 maxillofacial pigments, not for staining, but for evaluation of pigment stability. Results obtained from spectrophotometric measurements before and after solvent extraction demonstrated the effectiveness of solvent extraction in removing stains, while there was little or no change in the color of the pigments or the base elastomer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66797/2/10.1177_00220345810600100501.pd

A novel series of vanadium-sulfite polyoxometalates: synthesis, structural, and physical studies

Reaction of NH4VO3 with sulfur dioxide affords the hexanuclear cluster (NH4)(2)(Et4N)((VO)-O-IV)(6)(mu(4)-O)(2)(mu(3)-OH)(2)(mu(3)-SO3)(4)(H 2O)(2)]Cl center dot H2O (1), and the decapentanuclear host-guest compound (Et4N)(5){Cl subset of(VO)(15)(mu(3)-O)(18)(mu-O)(3)]}center dot 3H(2)O (2). Sequential addition of magnesium oxide to an acidic aqueous solution of NH4VO3 (pH approximate to 0) followed by (NH4)(2)SO3 resulted in the formation of either the non-oxo polymeric vanadium(IV) compound trans-(NH4)(2)V-IV(OH)(2)(mu-SO3)(2)] (3) or the polymeric oxovanadium(IV) sulfite (NH4)(VO)-O-IV-(SO3)(1.5)(H2O)]center dot 2.5 H2O (4) at pH values of 6 and 4, respectively. The decameric vanadium(v) compound {Na-4(mu-H2O)(8)(H2O)(6)} Mg(H2O)(6)]V-10(V)(O)(8)(mu(6)-O)(2)(mu(3)-O)(14)]center dot 3H(2)O (5) was synthesised by treating an acidic aqueous solution of NH4VO3 with MgO and addition of NaOH to pH approximate to 6. All the compounds were characterised by single-crystal Xray structure analysis. The crystal structure of compound I revealed an unprecedented structural motif of a cubane unit M-4(mu(4)-O)(2)(mu 3-OH)(2)] connected to two other metal atoms. Compound 3 comprises a rare example of a non-oxo vanadium(IV) species isolated from aqueous solution and in the presence of the reducing agent SO32-, while compound 4 represents a rare example of an open-framework species isolated at room temperature (20 degrees C). In addition to the synthesis and crystallographic studies, we report the IR and magnetic properties (for 1, 2 and 3) of these vanadium clusters as well as theoretical studies on compound 3

Solution identification and solid state characterisation of a heterometallic polyoxometalate {Mo(11)V(7)}: Mo(11)(VI)V(5)(V) V(2)(IV)O(52)(mu(9)-SO(3))](7-)

A polyoxomolybdenum/vanadium-sulfite {M(18)} cluster-based compound, Mo(11)(VI)V(5)(V)V(2)(IV)O(52)(mu(9)-SO(3))](7-), is reported that exhibits a unique structural motif, arising from the incorporation of five V(V) and two V(IV) ions into a {M(18)} cluster framework templated by SO(3)(2-); this cluster compostion was first identified using cryospray mass spectrometry