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Fischer's landmark discovery of transition-metal alkylidyne complexes two decades ago' initiated an extensive research effort that has resulted in the development of a large, diverse class of molecules that exhibit fascinating reaction chemistry.2 Much of the descriptive chemistry of these species hinges on the attribution of a formal bond order of 3 to the linkage between the alkylidyne ligand (CR) and the metal. This bonding description was initially based on the required valency of the ligated carbon atom1 and on X-ray crystallographic studies, the latter of which yielded the expected findings of a short M-C bond and a nearly linear M-C-R linkage.3 Direct evidence for the high multiplicity of the M-C bond order was ultimately provided by the sizable M-C force constant (k(W=C) = 7.00-7.40, k ( C e C ) = 5.18 mdyn A-l), which was determined, together with the M=C stretching frequency (v(M=C) = 1300-1400 cm-I), from an elegant series of vibrational spectroscopic experiments undertaken by Dao, Fischer, and co-workers on thearchetypal M(=CR)(C0)4X (M = Cr, Mo, W; R = Me, Ph; X = anionic ligand) complexes.4 Although v(M=CR) bands with similar frequencies have subsequently been observed for other alkylidyne compounds,2e~5 an acknowledged complication with the determination of v(M=C) and k(M=C) for M(CR)(CO)dX complexes arises from the vibrational complexity of their R groups; the M=C stretching coordinate is strongly coupled with other symmetry coordinates, especially the MC-C stretch and deformations of the R group, f University of Pittsburgh. t Wabash College. (1) Fischer, E. 0.; Kreis,G.; Kreiter, C. G.; Muller, J.; Huttner,G.; Lorenz, H. Dao,N. Q.; Fevrier, H.; Jouan, M.; Huy, N. H. T.; Fischer, E. 0.; Neugebauer, D. J. Organomet. Chem. 1982,241, C53-C56. (f) Dao, N. Q.; Fevrier, H.; Jouan, M.; Fischer, E. 0. Noun J. Chim. 1983,7,719-724. (9) Fischer, E. 0.; Friedrich, P.; Lindner, T. L.; Neugebauer, D.; Kreissl, F. R.; Uedelhoven, W.; Dao, N. Q.; Huttner, G. J . Organomet. Chem. 1983,247,239-246. (h) Dao, N. Q.; Fevrier, H.; Jouan, M.; Fischer, E. 0.; Rbll, W. J. Orgunomer. Chem. 1984,275,191-207. (i) Dao, N. Q.; Jouan, M.; Fonseca, G. P.; Huy, N. H. T.; Fischer, E. O.;J. Organomet. Chem. 1985,287,215-219. 6 ) Dao, N. Q.; Foulet-Fonseca, G. P.; Jouan, M.; Fischer, E. 0.; Fischer, H.; Schmid, J. C. R. Acad. Sci. Ser. 2 1988, 307, 245-250. (k) Foulet-Fonseca, G. P.; Jouan, M.; Dao, N. Q.; Fischer, H.; Schmid, J.; Fischer, E. 0. Spectrochim. Acta 1990,46A, 339-354. (1) Foulet-Fonseca, G. P.; Jouan, M.; Dao, N. Q.; Huy, N. H. T.; Fischer, E. 0.

A user-friendly set of computer-aided design (CAD) models and stereolithography (STL) files is reported for the production of simple and inexpensive 3D printed colorimeters. The designs shared here allow educators to provide active learners with tools for constructing instruments in activities aimed at exploring the technology and fundamental principles related to quantitative analysis. While previous efforts focused on fabricating inexpensive instruments from building blocks and other household items, 3D printing transcends the limitations of conventional tooling. The digital models described here are flexible in design, printed quickly, and each requires less than a dollar's worth of plastic filament. These designs are compatible with simple CAD software, such as Inventor Professional and Tinkercad, commonly available to educators and students. With the use of programs of this type, CAD files are easily modified in order to produce customized models for exploring a variety of concepts inaccessible to more conventional instruments. Developed with novice 3D printer users in mind, comprehensive slicer settings are provided to assist educators in obtaining reliable results. Once printed, the resulting colorimeter instruments perform very well when compared to commercially available spectrophotometers.

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The new zinc porphyrin/tungsten alkylidyne dyad Zn(TPP)-C[triple bond]CC(6)H(4)C[triple bond]W(dppe)(2)Cl (1) possesses novel photophysical properties that arise from a tunable excited-state triplet-triplet equilibrium between the porphyrin and tungsten alkylidyne units. Dyad 1 exhibits (3)(d(xy) <-- pi*(WCR)) phosphorescence with a lifetime that is 20 times longer than that of the parent chromophore W(CC(6)H(4)CCPh)(dppe)(2)Cl (2). The triplet-triplet equilibrium can be tuned by the addition of ligands to the Zn center, resulting in phosphorescence lifetimes for 1(L) that are up to 1300 times longer than that of 2. The "lifetime reservoir" effect exhibited by 1(L) is approximately 1 order of magnitude larger than previously reported examples of the phenomenon.