Interaction of electron acceptors with bases. Part 10.—Complexes of polycyanobenzenes with electron donors

Abstract

The apparent association constants of N,N,N',N'-tetramethyl-p-phenylenediamine complexes with polycyanobenzenes in chlorofom have been determined spectrophotometricaly. The stabilities of similar polynitrobenzene complexes have also been measured for comparison. The polycyanobenzene complexes have lower stabilities, higher excitation energies and lower extinction coefficients than those of the corresponding nitrobenzenes.

Interplay of Halogen and π–π Charge-Transfer Bondings in Intermolecular Associates of Bromo- or Iododinitrobenzene with Tetramethyl-p-phenylenediamine

“…Mulliken correlation between the absorption band of the complexes of TMPD with XDNB molecules (black rhombuses) and halogen-free nitro- and cyanosubstituted benzenes (open rhombuses) and the LUMOs’ energies of the electron acceptors: (1) BDNB, (2) IDNB, (3) 1,2,4,5-tetracyanobenzene, (4) 1,3,5-trinitrobenzene, (5) p -dinitrobenzene, (6) m -dinitrobenzene, (7) 1,3,5-tricyanobenzene, and (8) p -dicyanobenzene. (The spectral data for TMPD complexes with 3–8 are taken from ref , and LUMO energies resulted from the DFT computations in dichloromethane. )…”

“…In fact, since the middle 1950s, electron-rich aromatic TMPD molecules have been among the most common components of π-bonded donor–acceptor complexes similar to Structure I. − During the last 15 years, several halogen-bonded associates between TMPD and aliphatic and aromatic iodo-and bromocarbons showing very short intermolecular N···Br or N···I contacts were described as well. − As for the XDNB molecules, the structural characterization of IDNB complexes with 1,4-diazabicyclo[2.2.2]­octane and 4,4-bipyridine pointed out the ability of halodinitrobenzenes to form halogen-bonded associates. Besides, the numerous studies of molecular complexes of nitrobenzenes − suggested that BDNB and IDNB molecules may participate in the π–π charge-transfer bonding.…”

“…In fact, since the middle 1950s, electron-rich aromatic TMPD molecules have been among the most common components of π-bonded donor–acceptor complexes similar to Structure I. − During the last 15 years, several halogen-bonded associates between TMPD and aliphatic and aromatic iodo-and bromocarbons showing very short intermolecular N···Br or N···I contacts were described as well. − As for the XDNB molecules, the structural characterization of IDNB complexes with 1,4-diazabicyclo[2.2.2]­octane and 4,4-bipyridine pointed out the ability of halodinitrobenzenes to form halogen-bonded associates. Besides, the numerous studies of molecular complexes of nitrobenzenes − suggested that BDNB and IDNB molecules may participate in the π–π charge-transfer bonding. Thus, in order to elucidate the competition and interplay of halogen and π–π charge-transfer bonding involving nucleophilic and electrophilic aromatic molecules as well as to clarify the factors determining halogen-bond strength, we intend to carry out experimental studies of intermolecular associations of BDNB or IDNB with TMPD in solutions and in the solid-state together with the computational analysis of their interactions.…”

PAH/PAH(CF3)n Donor/Acceptor Charge‐Transfer Complexes in Solution and in Solid‐State Co‐Crystals

“…0.4 eV discrepancy is essentially the same: E ( λ max ) for ANTH/ANTH‐5‐1 is not lower than E ( λ max ) for ANTH/TCNB by 0.2 eV, it is higher than E ( λ max ) for ANTH/TCNB by 0.2 eV. Another example is a comparison of PYRN/TCNB ( λ max =497 or 500 nm in CHCl 3 (2.49±0.1 eV)) versus PYRN/ANTH‐6‐1 ( λ max =510 nm in 1,2‐C 2 H 4 Cl 2 (2.43 eV)). The λ max values, even after adjusting for CHCl 3 versus 1,2‐C 2 H 4 Cl 2 , indicate that ANTH‐6‐1 is the stronger acceptor in solution by ca.…”

n–π Electron donor–acceptor complexes. II. Aliphatic amines with dinitrobenzenes

“…The explanation that has been given for these facts (32) does not seem to be satisfactory for the n-T complexes studied, since, for a given amine, the K , follows the order of 1.2-DNB > 1.3-DNB > 1.4-DNB. The fact that both the donor and acceptor are unsymmetrical compounds suggests that there could be a preferred orientation of one molecule with respect to the other in the complex (33).…”