The titanocene imido complex 2 with a m-terphenyl moiety is synthesized by reacting Cp 2 Ti(η 2 -Me 3 SiC 2 SiMe 3 ) (1) with m-terphenyl azide. Subsequent reactivity studies with tetrahydrofuran, pyridine, and nitriles verify that these substrates act as two-electron donors, thus binding end-on to the titanium center to give the donor-stabilized titanocene imides 3a,b and 4a− c. Given the potential of the titanium center to act as an electron acceptor, 2 was reacted with phosphine oxides (OPEt 3 /OPPh 3 ) according to the Gutmann−Beckett method to get information about the Lewis acidity of 2 and to yield 5a,b. Complex 5a is one of the rare examples of structurally characterized titanium complexes with an η 1 -bound cyclopentadienyl ligand. Further insights into the Lewis acidity of 2 were obtained from the nitrile adducts 4a−c through IR spectroscopy and NMR spectroscopy (δ( 19 F) and 1 J C,F employing 4-fluorobenzontrile). In reactions of 2 with terminal alkynes, the respective titanium amido acetylides 6a,b were obtained, whereas reactions with internal alkynes demonstrate that 2 is not very prone to undergoing [2 + 2] cycloaddition reactions.

Parallel alignment of dipolar electron-donor-π-bridge-electron-acceptor entities can strongly enhance their nonlinear optical properties. This favorable arrangement can be in principle achieved by linking these units covalently or through metal coordination. Four dipolar single-strand chromophores decorated with a 5-electron-donor-5'-electron-acceptor-modified 2,2'-bipyridine functionality were synthesized. For two of these chromophores triple-stranded dendritic structures were successfully formed. All of the compounds were characterized with respect to their linear and nonlinear optical properties. For the aldehyde derivatives an enhancement of the first hyperpolarizability of 4.5 rather than 3 was obtained when going from single to triple strands. Theoretical calculations with density functional theory suggest that interstrand transitions contribute to the optical properties of the dendritic structures.

Two hexadentate bipyridine ligands and their RuII and NiII complexes were prepared. The helical alignment of the three electron‐donor–π‐bridge–electron‐acceptor (d‐π‐A) single‐strands with bundle architecture in cooperation with the metal center can strongly enhance the nonlinear optical (NLO) properties. The complexation of the novel cage‐type hexadentate ligands with a paramagnetic NiII‐core almost doubles the βHRS values compared with the corresponding diamagnetic RuII complexes. The hyper‐Rayleigh scattering (HRS) was performed with a highly sensitive setup for simultaneous discrimination between multi‐photon fluorescence and the molecular first hyperpolarizability.