TY  - JOUR
A1  - Venkatraman, S.
A1  - Kumar, R.
A1  - Sankar, J.
A1  - Chandrashekar, T. K.
A1  - Sendhil, K.
A1  - Vijayan, C.
A1  - Kelling, Alexandra
A1  - Senge, Mathias O.
T1  - Oxasmaragdyrin-ferrocene and oxacorrole-ferrocene conjugates : Synthesis, structure, and nonlinear optical properties
N2  - Ferrocenyl macrocyclic conjugates involving 22pi oxasmaragdyrins and 18pi oxacorroles have been synthesized and characterized. The direct covalent linkage of the ferrocenyl moiety to the meso position of the macrocycle is achieved by simple oxidative coupling of appropriate precursors with trifluoroacetic acid as catalyst. The electronic coupling between the ferrocenyl moiety and the macrocyclic pi system is apparent from: a) the red shifts (293-718 cm(-1)) of the Soret and Q-bands in the electronic absorption spectra of ferrocenyl conjugates; b) the shift of oxidation potentials (50 130 mV) of both the ferrocene and the corrole rings to the positive potentials; and c) considerable shortening of the C-C bond which connects the ferrocene and the meso-carbon atom of the macrocycle. The single-crystal X-ray structure of oxasmaragdyrin-ferrocene conjugate 9 reveals the planarity of the 22pi skeleton with very small deviations of the meso-carbon atoms. The meso-ferrocenyl substituent has a small dihedral angle of 38degrees, making way for mixing of the molecular orbitals of the ferrocene and the macrocycle. However, the other two meso substituents are almost perpendicular to the mean plane, defined by the three meso carbon atoms. Classical C-(HO)-O-... and nonclassical C- H(...)pi interactions lead to a two-dimensional supramolecular network. Ferrocene-smaragdyrin conjugate 9 bonds to a chloride ion in the protonated form and a rhodium(i) ion in the free base form. Nonlinear optical measurements reveal a larger nonlinear refractive index (-5.83 x 10(-8) cm(2) W-1) and figure of merit (2.28 x 10(-8) cm(3)W(-1)) for the rhodium smaragdyrin-ferrocene conjugate 19 than for the others, suggesting its possible application in optical devices
Y1  - 2004
SN  - 0947-6539
ER  - 
TY  - JOUR
A1  - Rath, Harapriya
A1  - Anand, V. G.
A1  - Sankar, J.
A1  - Venkatraman, S.
A1  - Chandrashekar, T. K.
A1  - Joshi, Bhawani S.
A1  - Khetrapal, C. L.
A1  - Schilde, Uwe
A1  - Senge, Mathias O.
T1  - Core-Modified Hexaphyrins; Characterization of Two- and Four-Ring Inverted 26 ô Aromatic Macrocycles
Y1  - 2003
UR  - http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/ol035408q
ER  -