Contribution of Diffuse Reflectance Spectroscopy to Monitoring the Synthesis Improvement of Encapsulated Complexes

Abstract

Diffuse reflectance spectroscopy (DRS) can be regarded as a solid state technique contribution to monitoring the process of encapsulation of transition metal complexes into cavities of zeolites. By employing DRS, it was revealed that the effectiveness of a method suggested for higher encapsulation of a tris(bipyridine)cobalt(II) complex into zeolite Y can easily be manifested. In addition to that, simple diffuse reflectance spectra give information about a relative amount of two spin states of the cobalt bipyridine complexes and their alteration upon the method used.

Flexible Co(II)-and Ni(II)-Based Cationic 2D Metal–Organic Frameworks Based on a Charge-Neutral (O,O)-Donor Bridge

“…The UV/vis absorption of solid 1 and 2 was investigated via diffuse reflectance spectroscopy (DRS). As shown in Figure 4b, compound 1 possesses one absorption band in the green region with λ max = 530 nm, apparently corresponding to d-d electron transitions in Co 2+ , hexa-coordinated by oxygen [80,81] and providing its pink color as a mixture of low-wavelength violet and high-wavelength red color components. Oppositely, the DRS spectrum of 2 contains an absorption band in the violet-blue region with λ max = 418 nm and a very wide weak band in the red/NIR area (λ max ≈ 776 nm), providing a green color quite typical of Ni 2+ complexes with an octahedral [82,83] oxygen environment.…”