Homoleptic Carbonyls of the Second-Row Transition Metals:  Evaluation of Hartree−Fock and Density Functional Theory Methods

Abstract

The homoleptic mono- and multinuclear carbonyls for Mo, Tc, Ru, and Rh, namely, Mo(CO)6, Ru(CO)5, Tc2(CO)10, Ru3(CO)12, Rh4(CO)12, and Rh6(CO)16, are investigated theoretically by the Hartree-Fock method and three density functional theory (DFT) methods, i.e., BP86, B3LYP, and MPW1PW91, along with the SDD ECP basis sets. The results predicted by all the methods are basically in agreement with each other. The MPW1PW91 and BP86 methods predict geometric parameters and vibrational spectra, respectively, closest to the experimental values. For Ru3(CO)12 the relative energies of the D3h isomer with only terminal CO groups and the C2v isomer with two bridging CO groups are within 3 kcal/mol of each other with the lower energy isomer depending upon the computational method used. For Rh4(CO)12 the global minimum is predicted to have C3v symmetry, with three bridging and nine terminal carbonyls, in accord with experiment. The Rh6(CO)16 structure has Td symmetry and satisfies the Wade-Mingos rules for an octahedral cluster. Using the MPW1PW91 method the Rh-Rh distances in Rh4(CO)12 are found to be 2.692 Å and 2.750 Å and those in Rh6(CO)16 to be 2.785 Å.

Inhibition of Alkyne Cyclotrimerization to Arenes on a Metal Site by Four‐Electron Donation through Simultaneous Sigma and Pi Bonding: The Tris(alkyne)Tungsten Carbonyls

“…[24] The MPW1PW91 functional has been shown to be typically more reliable than the first generation functionals for carbonyl derivatives of the second and third row transition metals. [25,26] For the third-row transition-metal derivatives effective core potential (ECP) and related basis sets provide a simple but efficient approach for reducing the computational effort while considering relativistic effects. In this study the ECP basis set SDD (Stuttgart-Dresden ECP plus DZ), [27,28] is used for the tungsten atom.…”

“…[32] In the present study, the MPW1PW91 and BP86 methods are found to agree fairly well with each other in predicting the structures of the (R 2 C 2 ) 3 W(CO) n (R = CH 3 , CF 3 ) derivatives. Since previous work [25] indicates that the MPW1PW91 method generally gives closer agreement with experimental bond lengths, the bond lengths obtained by the MPW1PW91 method are given in the discussion unless otherwise indicated. A total of 24 structures for the neutral (R 2 C 2 ) 3 W(CO) n (R = CH 3 ,CF 3 ) (n = 3, 2, 1, 0) compounds are reported in this paper.…”

Comparison of Isoelectronic Heterometallic and Homometallic Binuclear Cyclopentadienylmetal Carbonyls: The Iron–Nickel vs. the Dicobalt Systems

“…[22][23][24][25][26][27][28][29][30] Extensive experience suggests that the pure GGA functional BP86 is often more reliable for many organometallic systems than the popular hybrid functional B3LYP when compared with available experimental results. [17,31,32,33] In the present study, complete geometrical optimization and vibrational frequency analyses were carried out using the DFT functional BP86 with DZP basis sets. The BP86 functional combines Becke's 1988 exchange functional (B) with Perdew's 1986 correlation functional.…”

“…The isoelectronic species Cp 2 Co 2 (CO) was reinvestigated [32] for comparison with Cp 2 FeNi(CO) using the same level of theory. The singlet states of Cp 2 Co 2 (CO) were studied in the previous work using a coarser integration grid (75,302) than the (99,590) integration grid used in this work; this leads to some significant imaginary frequencies.…”

NMR (13C, 17O), IR and Raman Studies of Poly-nuclear Carbonyls Transition Metal Carbonyls : A DFT Application

“…But unlike the vast variety of NMR parameters of 20 mono-and bi-nuclear [8][9][10][11][12][13][14] carbonyls studied by our group of workers 1,4 ,only a little had been reported on NMR studies by computational methods for poly-nuclear [18][19][20][21][22] carbonyls as follows:…”