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Syntheses, Crystal Structures and Photophysical Measurements of Phosphite‐Substituted Schiff Base and Azobenzene Ligands
Author(s) -
MurphyJolly Makeba B.,
Owens Samuel B.,
Freeman Jason L.,
Gray Gary M.,
Lawson Christopher M.,
Shelton David P.
Publication year - 2010
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201000557
Subject(s) - chromophore , chemistry , azobenzene , schiff base , ligand (biochemistry) , crystal structure , intramolecular force , metal , crystallography , photochemistry , stereochemistry , molecule , organic chemistry , biochemistry , receptor
Abstract Organic chromophores with charge asymmetry may exhibit significant second‐order nonlinear optical (NLO) properties. Metal complexes have been used as the donor, the acceptor, or as the bridge in some of these chromophores. Metal complexes may also be useful in dipolar chromophore orientation and in the building of large molecular structures, but this approach remains largely unexplored. We herein report the syntheses and characterization of a novel class of phosphite‐containing chromophores, O 2 N‐1‐C 6 H 4 ‐4‐CH=N‐1‐C 6 H 4 ‐4‐OP(OC 6 H 4 ) 2 ( 2 ) and O 2 N‐1‐C 6 H 4 ‐4‐X=N‐1‐C 6 H 4 ‐4‐OP(OC 10 H 6 ) 2 [X = CH ( 3 ), N ( 4 )], and their transition‐metal complexes, cis ‐Mo(CO) 4 ( 2 ) 2 ( 5 ), PdCl 2 ( 2 ) 2 ( 6 ), and cis ‐Mo(CO) 4 ( 3 ) 2 ( 7 ). The X‐ray crystal structures of 2 and 5 show that coordination of the phosphite ligand to the metal atom does not alter the conformation of the chromophore. Hyper‐Rayleigh scattering (HRS) measurements of the compounds in 1,4‐dioxane at 1064 nm indicate that phosphite functionalization causes a small decrease in the β values of the Schiff‐base chromophores { β [esu]: 47 × 10 –30 ( 1 ), 25 × 10 –30 ( 2 ), 30 × 10 –30 ( 3 } and no change in the β value of the azo chromophore { β [esu]: 62 × 10 –30 ( 4 )}. The larger β values of the cis ‐Mo(CO) 4 L 2 complexes { β [esu]: 38 × 10 –30 ( 5 ), 41 × 10 –30 ( 7 )} as compared to those of the ligands ( 2 and 3 ) are consistent with the 90° orientation of two chromophores in the complexes.