Transition metal complex directed lead bromides with tunable structures and visible light driven photocatalytic properties

Abstract

With similar transition metal (TM) complex cations as structural directing agents (SDAs), six new hybrid lead bromides were synthesized and structurally characterized as [Co(2,2-bipy)]{[Co(2,2-bipy)]PbBr} (1), [Co(2,2-bipy)Br]PbBr (2), [TM(phen)]PbBr (TM = Co (3) and Ni (4)), [Co(2,2-bipy)]PbBr (5) and [Co(2,2-bipy)]PbBr·CHCN (6) with distinct structural types from zero-dimensional (0D) unit, one-dimensional (1D) chain to two-dimensional (2D) layer. Compound 1 contains the 0D {[Co(bipy)]PbBr} units built from the [PbBr] ring attached by three unsaturated [Co(2,2-bipy)] complexes via Co-Br bonds. Under the direction actions of different SDAs, compounds 2 and 3-4 contain two different types of [PbBr] chains based on the same octahedral [PbBr] units but with distinct connecting manners, respectively. Using the same [Co(2,2-bipy)] as SDA, compound 5 reveals a 1D [PbBr] double chain, whereas compound 6 features a 2D complex [PbBr] layer. The UV/vis diffuse-reflectance measurements reveal that the title compounds feature tunable band gaps of 1.70-2.29 eV. Under the visible light irradiation, sample 6 exhibits efficient and stable photocatalytic degradation activities over organic pollutants, which mainly originates from the multi-electronic effects of the TM complex cations. A possible photocatalytic mechanism is also proposed based on the radical trapping experiments and electronic band structural calculations.

A 3D Iodoplumbate Semiconducting Open Framework with Visible‐light‐induced Photocatalytic Performance

“…Herein, Ammonium oxalate (AO), tert ‐butyl alcohol (TBA) and Benzoquinone (BQ) were chosen as hole (h + ), hydroxyl radical ( . OH) and the superoxide (O 2 .− ) scavengers, respectively . The AO and BQ have more obvious influence on the photocatalytic activity, which indicating that h + and O 2 .− are the main active species in the photodegradation process (Figure c).…”

“…Herein, Ammonium oxalate (AO), tert-butyl alcohol( TBA) and Benzoquinone (BQ) were chosen as hole (h + ), hydroxyl radical( COH) and the superoxide (O 2 C À )s cavengers, respectively. [16,43,[52][53][54][55][56][57] The AO and BQ have more obviousi nfluence on the photocatalytic activity,w hich indicating that h + and O 2 C À are the main active speciesint he photodegradation process (Figure 3c).Compound 1,a sw ell as the reportedh ybrid halometallates containing conjugatedo rganic cations, such as [N-ethyl-4-cyanopyridinium][Ag 2 I 3 ], [9] [N-benzylpyridinium] 2 [Cu 6 I 8 ], [58] [(Me) 2 -2,2'-bipy][Cu 8 I 10 ], [55] [Ni(2,2'-bipy)(THF) 2 (H 2 O) 2 ](Ag 10 I 12 )·2DMF (THF = tetrahydrofuran, DMF = N,N'-dimethylformamide, 2,2'bipy = 2,2'-bipyridine), [59] and [Pb 5 Cu 2 I 16 ][(Me) 2 (4-TPT)] 2 (4-TPT = 2,4,6-tris(4-pyridyl)-1,3,5-triazine), [45] possess narrow band gaps of 1.35-2.74 eV.R eportedly, on the basis of electronic band structuralc alculation, the conductionb ands of most conjugated organic cations directed halometallates are primarily occupied by the conjugatedo rganic moieties, while the valence bandsa re mainly made up by anionic inorganic networks. [46,55] The contribution of conjugated organic moieties to conduction bands decreasing the energy position and leading to the small band gaps.…”

Tripyridine‐Derivative‐Derived Semiconducting Iodo‐Argentate/Cuprate Hybrids with Excellent Visible‐Light‐Induced Photocatalytic Performance

“…Ammonium oxalate (AO), Benzoquinone (BQ) and tert ‐butyl alcohol (TBA) were selected as scavengers for hole (h + ), the superoxide (O 2 .− ) and hydroxyl radical ( . OH), respectively . Obviously, for the MO solutions, the respective inhibition rates of AO, BQ, and TBA as scavengers are 95.5 %, 97.1 % and 95.4 %, indicating that h + , O 2 .− and .…”

“…To get an in-depth understanding the catalytic property and study the possible mechanism, the radical trappinge xperimentsw ere carried out to identify the main reactive species responsible for the degradation.A mmonium oxalate (AO), Benzoquinone (BQ) and tertbutyl alcohol (TBA) weres elected as scavengers for hole (h + ), the superoxide (O 2 C À )a nd hydroxyl radical (COH), respectively. [51,52,68,69] Obviously,f or the MO solutions, the respective inhibition rates of AO, BQ, and TBAa ss cavengers are 95.5 %, 97.1 %a nd 95.4 %, indicating that h + ,O 2 C À and COH all play very important roles for the degradation of MO. For the MV solutions, the inhibition rates of AO, BQ, and TBA as scavengers are 90.0 %, 60.6 %a nd 80.0 %, suggesting that O 2 C À was more activet han h + and COH in decomposition of MV.T of urther study the relationship between the structure and optical property,e lectronic structure calculations were performed based on density functional theory.…”

“…Lei and Yue et al. systematically investigated halogenides in the presence of transition metal‐complexes, which display efficient photocatalytic properties . Zhang, Fu, and co‐workers.…”