666837-84-9Relevant academic research and scientific papers
Cationic borabenzene complexes as electron accepting groups for molecular material with nonlinear optical properties
Behrens,Meyer-Friedrichsen,Heck
, p. 1421 - 1430 (2003)
The dinuclear dipolar borabenzene complexes [(η5-C 5H5)Fe{μ-(η5-C5H 4)C2(η6-BC5H5)}ML]X [ML = Ru(η6-C6H6), X = Cl (4aCl), PF 6 (4aPF6), B(C6H5)4 (4aBPh4); ML = Rh(η5-C5Me5), X = Cl (4bCl), PF6 (4bPF6); ML = Ir(η5-C 5Me5), X = Cl (4cC1), PF6 (4cPF6)] were synthesized by a nucleophilic substitution reaction of the trimethylphosphane adduct of borabenzene (1) with lithium ferrocenylacetylide, subsequent lithium-thallium exchange and coordination of the appropriate ML unit obtained from [Ru(η6-C6H6)Cl(μ -Cl)]2, [M(η5-C5Me5)Cl(μ -Cl)]2 (M = Rh, Ir); the formed chloride salts, which are soluble in water, were transformed to the PF6 salts by adding [NH 4][PF6] to the corresponding water solution. BPh 4 salts can be produced, when a methanolic solution of Na[BPh 4] were added to CH2Cl2-solutions of the appropriate PF6 salt. X-ray structure analyses of single crystals of 4aBPh4 and 4bPF6 were successful, illustrating the cation 4a+ in an ideal cis-conformation, whereas 4b+ displays a cis- and trans-conformation. Spectroscopic and cyclic voltammetry studies reveal a small but distinct donor-acceptor interaction between the ferrocenyl donor and the cationic borabenzene complex acceptor which increases in the order 4aPF6 6 6. The nonlinear optical properties of these donor-acceptor complexes were studied by means of hyper-Rayleigh scattering (HRS), resulting in the determination of small values for the first hyperpolarisability β, which increase in the same order as the donor-acceptor interaction.
