Molecular Structure of Phthalocyaninatotin(II) Studied by Gas-Phase Electron Diffraction and High-Level Quantum Chemical Calculations

Abstract

The molecular structure of phthalocyaninatotin(II), Sn(II)Pc, is determined by density functional theory (DFT/B3LYP) calculations using various basis sets and gas-phase electron diffraction (GED). The quantum chemical calculations show that Sn(II)Pc has C4V symmetry, and this symmetry is consistent with the structure obtained by GED at 427 degrees C. GED locates the Sn atom at h(Sn) ) 112.8(48) pm above the plane defined by the four isoindole N atoms, and a N-Sn bond length of 226.0(10) pm is obtained. Calculation at the B3LYP/ccpVTZ/cc-pVTZ-PP(Sn) level of theory gives h(Sn) ) 114.2 pm and a N-Sn bond length of 229.4 pm. The phthalocyanine (Pc) macrocycle has a slightly nonplanar structure. Generally, the GED results are in good agreement with the X-ray structures and with the computed structure; however, the comparability between these three methods has been questioned. The N-Sn bond lengths determined by GED and X-ray are significantly shorter than those from the B3LYP predictions. Similar trends have been found for C-Sn bonds for conjugated organometallic tin compounds. Computed vibrational frequencies give five low frequencies in the range of 18-54 cm-1, which indicates a flexible molecule.

Understanding the structure of salicyl hydrazone metallocomplexes: crystal structure, AIM and Hirshfeld surface analysis of trichloro-(N-salicylidenebenzoylhydrazinato-N,O,O′)-tin(IV)

“…E bond (Sn-O) in 1 is in the range obtained for Sn 2 (OCH 2 CH 2 NMe 2 ) 2 (OPh) 2 (24-52 kcal/mol) [20] and also in good accord with the ΔH value of hydroxydistannoxane dimerization (MP2/6-311 + G(d)) (49.7 kcal/mol) [63]. At the same time, value of E bond (Sn-N) = 24-45 kcal/mol in 1 significantly varies from those previously calculated (9, 15 and 13-18 kcal/mol for [(Me 3 Si) 2 NSnL] 2 [64], phthalocyaninatotin(II) [65] and Sn 2 (OCH 2 CH 2 NMe 2 ) 2 (OPh) 2 ) [20].…”

Bis(μ2-2-(dimethylamino)ethoxo-N,O,O)-di(phenolato-O)ditin(II): a high-resolution single-crystal X-ray diffraction and quantum chemical study

“…In accordance with , the energy of the Me 2 N!Sn bond in [(Me 3 Si) 2 NSnL] 2 is 36.0 kJ mol À1 . At the same time, Strenalyuk et al (2008) estimated the E bond for Sn-N to be 61.71 kJ mol À1 in the structure of phthalocyaninatotin(II) [r(Sn-N) = 2.042 Å ]. The latter value is closer to E bond (N!Sn) obtained from (r) in (I).…”

Accurate molecular structure of nickel phthalocyanine (NiN8C32H16): Gas-phase electron diffraction and quantum-chemical calculations

“…It is generally known [9,12,51,52] that introduction of small or large central atoms into the coordination cavity causes a conformation stress of a relatively rigid macrocycle. This strain can be reduced by moving the isoindole nitrogen atoms towards or away from the cavity center, by the displacement of the central metal atom out of the N 4 C 8 plane or by the ''ruffling'' of the macrocycle core.…”

“…Since that time the molecular structure of only four Pc macrocycles (F-PcZn, H 2 Pc, and Cl-MPc, where M = Al, Ga) [9][10][11] have been studied, and three complexes (ZnPc, SnPc, CuPc) have been re-investigated by GED [9,12,13]. It should be noted that the re-investigation of the ZnPc, SnPc, CuPc complexes resulted in a considerably higher accuracy molecular structures, as compared with the previous investigations demonstrating the reliability of the GED method when being associated with high-level quantum chemical calculations for the structure determination of the MPc complexes.…”