Synthesis, structures and luminescence of several coordination complexes based on β-octamolybdate and Ag/Cu phosphine units

• Published in: CrystEngComm 2024-08, Vol.26 (32), p.4329-4338
• Main Authors: Yu, Yi-Qi, Sun, Shang-Bin, Deng, Wen-Hao, Li, Jian, Lu, Zhi-Yi, He, Jia-Hui, Wang, Long-Sheng, Meng, Xiang-Gao
• Format: Article
• Language: English
• Subjects: Anions; Atomic properties; Atomic structure; Coordination compounds; Copper; Electrons; Metal clusters; Oxygen atoms; Phosphines; Self-assembly; Silver; Single crystals; Solid state; Trimers; Weight loss
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/d4ce00496e

Four new POM-based coordination complexes [Cu(TPP) 2 (CH 3 CN) 2 ] 2 {[Cu(TPP) 2 ] 2 (β-Mo 8 O 26 )}·2CH 3 CN ( 1 ) (TPP = triphenylphosphine), {[Ag(TPP)] 2 ·[Ag(TPP) 2 ] 2 ·(β-Mo 8 O 26 )}·6DMF ( 2 ), {[Cu 2 (DPPM) 2 (CH 3 CN)] 2 (β-Mo 8 O 26 )}·2CH 3 CN·2DCM ( 3 ) (DPPM = bis(diphenylphosphino)methane), and {[Ag 2 (DPPM) 2 ·(CH 3 CN)] 2 (β-Mo 8 O 26 )}·2CH 3 CN·2DCM ( 4 ) were prepared through the self-assembly of α-octamolybdates and the corresponding Cu/Ag phosphine building blocks. Single crystal X-ray diffraction reveals that compound 1 consists of two cations of [Cu(TPP) 2 (CH 3 CN) 2 ] + and one anion of {[Cu(TPP) 2 ] 2 (β-Mo 8 O 26 )} 2− ; the anion of {[Cu(TPP) 2 ] 2 (β-Mo 8 O 26 )} 2− can be viewed in such a way that the central cluster of β-Mo 8 O 26 are coordinated with two Cu(TPP) 2 units via terminal oxygen atoms to form a linear trimer; compound 2 is a neutral cross-like pentamer which is made up of the central β-Mo 8 O 26 coordinated with two equatorial Ag(TPP) 2 units and two Ag(TPP) units above and below the β-Mo 8 O 26 cluster via the terminal oxygen atoms; compounds 3 and 4 can be viewed as a trimer consisting of two binuclear metal clusters of {[Cu 2 (DPPM) 2 (CH 3 CN)] 2 } 2+ or {[Ag 2 (DPPM) 2 (CH 3 CN)] 2 } 2+ bridged by one β-Mo 8 O 26 cluster via terminal oxygen atoms. Their structures are further evidenced by FT-IR and PXRD. TGA study indicates that the skeleton of compounds 1-4 is stable up to 250-290 °C and then a rapid weight loss followed. Their band gaps can be calculated ( E g value: 2.27 eV for 1 , 3.14 eV for 2 , 2.66 eV for 3 , and 3.16 eV for 4 ) using the Tauc's method according to their solid state UV diffuse reflection spectra. Upon irradiation at 211 nm, compounds 1-4 exhibit a series of successive emissions around 360 nm, 380 nm and 400 nm, which demonstrate a similar solid state emission compared to their corresponding Cu/Ag phosphine building blocks. Four POM-based coordination compounds were obtained by the self-assembly of α-octamolybdates and luminescent Cu/Ag phosphine units, which maintain the luminescence feature of their precursors of Cu/Ag phosphine units.