Bis[2,6-bis(1-methyl-1H-benzimidazol-2-yl-κN³)pyridine-κN]zinc dipicrate methanol disolvate

Abstract

Key indicators: single-crystal X-ray study; T = 153 K; mean (C-C) = 0.003 Å; R factor = 0.039; wR factor = 0.111; data-to-parameter ratio = 12.5.In the title compound, [Zn(C 21 H 17 N 5 ) 2 ](C 6 H 2 N 3 O 7 ) 2 Á2CH 3 OH, the Zn II atom is coordinated by six N atoms from two tridentate 2,6-bis(1-methyl-1H-benzimidazol-2-yl)pyridine ligands in a distorted octahedral environment. In the crystal, the picrate anions and methanol solvent molecules are connected by O-HÁ Á ÁO hydrogen bonds. Weak intermolecular C-HÁ Á ÁO hydrogen bonds are also observed. Related literature ExperimentalCrystal data [Zn(C 21

Key Strategy for the Rational Incorporation of Long-Lived NIR Emissive Cr(III) Chromophores into Polymetallic Architectures

“…Interestingly, the alkyne bridges impose approximate coplanarity between the phen and bbzpy moieties, which is compatible with πdelocalization and prospective efficient intermetallic electron and/or energy transfers in related CrLMLCr units. 47 The average Zn−N bond distance of 2.1 Å is in fair agreement with 2.15 Å observed for similar monometallic complexes, 100 , where r Cr−H is the Cr•••H distance. 101,102 With this in mind, the nuclear relaxation times collected in Table 1 for protons can be considered as direct estimations of their separation from the Cr III atoms in solution, which allows direct comparisons between solid state and solution structures.…”

“…units 47. The average Zn-N bond distance of 2.1 Å is in fair agreement with 2.15 Å observed for similar monometallic complexes,100 which demonstrates the very weak effect (if any) of the appended chromium chromophores on the central pseudo-octahedral [Zn(bbzpy)2] 2+unit. The large separation between the two stereogenic centers (intramolecular CrZn distances of 13.91 Å and 13.98 Å, and intramolecular CrCr distance of 27.53 Å) in CrLZnLCr is consistent with the absence of different sets of NMR signals observed for the diastereomeric mixture in solution.…”

“…Interestingly, the alkyne bridges impose approximate coplanarity between the phen and bbzpy moieties, which is compatible with π-delocalization and prospective efficient intermetallic electron and/or energy transfers in related Cr L M L Cr units . The average Zn–N bond distance of 2.1 Å is in fair agreement with 2.15 Å observed for similar monometallic complexes, which demonstrates the very weak effect (if any) of the appended chromium chromophores on the central pseudo-octahedral [Zn­(bbzpy) 2 ] 2+ unit. The large separation between the two stereogenic centers (intramolecular Cr···Zn distances of 13.91 and 13.98 Å, and intramolecular Cr···Cr distance of 27.53 Å) in Cr L Zn L Cr is consistent with the absence of different sets of NMR signals observed for the diastereomeric mixture in solution.…”