title: An insight into the communication between β-olefin/phenyl olefin-mediated acceptors and porphyrin π-system: a way to establish porphyrin based chemodosimeters and chemosensors.
abstract: The synthesis of three new classes of mixed β-pyrrole substituted tetraphenylporphyrins, MTPP(R), MTPP(Br)2(R) (where R = -CH[double bond, length as m-dash]C(CN)2, -CH[double bond, length as m-dash]C(CN)(COOC2H5), -CH[double bond, length as m-dash](CN)(COOH) and M = 2H, Ni(ii), Cu(ii)) and MTPP(NO2)(Ph-p-R')2(R' = -CHO and -CH[double bond, length as m-dash]C(CN)2and M = 2H, Ni(ii), Cu(ii)) have been reported. The crystal structures of CuTPP(Br)2-ECA (7a), NiTPP(NO2)(Ph-p-CHO)2(9) and NiTPP(NO2)(Ph-p-CH[double bond, length as m-dash](CN)2)2(10) are highly nonplanar among β-trisubstituted porphyrins reported to date as evidenced from the mean displacement of β-pyrrole carbon (ΔCβ) in the range ±(0.39-0.674) Å. The olefin mediated ethyl cyanoacetate is in plane with the porphyrin core in CuTPP(Br)2-ECA (the dihedral angle relative to the pyrrole NC4-mean plane is 39.81°) while dicyanovinyl stays aside for NiTPP(NO2)(Ph-p-CH[double bond, length as m-dash](CN)2)2(dihedral angles relative to the pyrrole NC4-mean plane are 75.03° and 67.47°). NiTPP-MN (2), NiTPP-ECA (3), NiTPP(Br)2-MN (6) and NiTPP(Br)2-ECA (7) act as chemodosimeters for toxic CN-ions whereas NiTPP-CAA (4) and NiTPP(Br)2-CAA (8) act as chemosensors to detect toxic ions such as CN-, F-and OAc-depending on the acceptor strength and an obstacle in the conjugation pathway. The dicyanovinyl group in the phenyl olefinic-mediated porphyrin NiTPP(NO2)(Ph-p-CH[double bond, length as m-dash](CN)2)2(10) also acts as chemodosimeter for CN-ions but no vivid changes are observed via different spectroscopic methods.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee - 247667, India. sankafcy@iitr.ac.in.
authors.forename: Mandeep K
authors.initials: MK
authors.lastname: Chahal
authors.affiliation: Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee - 247667, India. sankafcy@iitr.ac.in.
authors.forename: Muniappan
authors.identifier: http://orcid.org/0000-0001-6667-3759
authors.initials: M
authors.lastname: Sankar
authors.affiliation: Department of Chemistry, Howard University, Washington, DC 20059, USA.
authors.forename: Ray J
authors.initials: RJ
authors.lastname: Butcher