The Catalytic Activities of Carbocyclic Fused Pyridineimine Nickel Complexes Analogues in Ethylene Polymerization by Modeling Study

Abstract

In this work, two carbocyclic fused pyridineimine nickel analogue systems (Ni1 and Ni2) with different fused member rings were investigated to reveal the relationship between catalyst structure and reaction activity. Multiple linear regression analysis was performed by means of five electronic descriptors and two steric descriptors, including the Hammett constant (F), effective net charge (Qeff), energy difference (ΔE), HOMO–LUMO energy gap (Δε1, Δε2), open cone angle (θ), and bite angle (β). Very good values of correlation coefficient (R2) over 0.938 were obtained by using a combination of effective net charge (Qeff) and open cone angle (θ) for both individual analysis and comparisons between analogue systems. By analyzing the contribution of descriptors, it indicates that the dominant descriptor is effective net charge (Qeff) in the Ni1 system and open cone angle (θ) in Ni2 systems, respectively. This may explain the different variation trends of catalytic activities in two Ni complexes systems as a function of substituents.

Catalytic Performance of Cycloalkyl-Fused Aryliminopyridyl Nickel Complexes toward Ethylene Polymerization by QSPR Modeling

“…The descriptors are then calculated by the CODESSA software, generating around 350 descriptors for each complex. As in previous studies [39][40][41][42], there are seven selfdefined descriptors which show good correlations with catalytic activity. Therefore, these descriptors are also calculated for each complex as shown in Table S8.…”

Catalytic Performance of Cobalt(II) Polyethylene Catalysts with Sterically Hindered Dibenzopyranyl Substituents Studied by Experimental and MLR Methods

“…On the basis of optimized structures, the values of descriptors were calculated and are listed in Table 5 . Herein, seven descriptors are considered based on our previous studies [ 38 , 39 , 40 ], including effective net charge ( Q eff ), HOMO–LUMO energy gaps (Δ ε 1 , Δ ε 2 ), energy difference (Δ E ), Hammett constant ( F ), bite angle ( β ), and open cone angle ( θ ). The detail definition and calculation procedure of each descriptor are provided in Supplementary Materials .…”

n-Butene Synthesis in the Dimethyl Ether-to-Olefin Reaction over Zeolites

“…Multiple regression analysis, which can provide effective information for the development of catalysts, was performed to model the performance of the catalysts [40][41][42]. Malik et al reported that the analysis results can explain the different variation trends of catalytic activities using similar catalysts [42].…”