Alkynyl structure properties studies

Viewed as a whole, it appears that the results of the structural, spectroscopic, theoretical, and other physical studies on metal-alkynyl complexes cannot be interpreted within a single, simple picture of the nature of metal-alkynyl bonding. In view of the fact that understanding the electronic-structural basis of the reactions of metal-alkynyl complexes and the physical properties of the advanced materials developed from them requires a clear picture of this bond, further work in this area would be highly desirable. Of particular value would be studies that applied a combination of the experimental techniques described above and theoretical calculations to a series of archetypal metal-alkynyl complexes from across the transition series, so as both to gauge the effect of the metal on the nature of the M-CCR bond and to clarify the benchmark parameters for each technique within different metal-alkynyl bonding regimes. 

The NLO properties of organometallic and coordination complexes are also rich (21, 184, 279-296). Metal-alkyne complexes were first reported 1960 (297) and have recently attracted significant interest because of their potential in materials applications (2, 298). Studies of these types (299) have resulted in the development of structure-NLO response relationships for quadratic optical nonlinearities (p-value), which increase with valence electron count and ease of oxidation of metal. The amplitude is also tunable by ancillary ligand modification and substitution. Select small alkynyl complexes have been shown to exhibit p values at 1064 nm > 2600 x 10 ° esu (299). 

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