title: Multivariate statistical analysis of mid-infrared spectra for a G1 allyl-terminated carbosilane dendrimer.
abstract: The FTIR spectra were measured for G1 allyl terminated carbosilane dendrimer over a temperature range of 25-200°C to explore the temperature-dependent changes. The dendrimer spectra exhibited complicated patterns and thus were analyzed by both the exploratory principal component analysis (PCA) and two-dimensional (2D) correlation spectroscopy. Boltzmann fitting and score plots of PCA evidenced the phase transition temperature to be about 172°C. Frequency variables, which strongly contributed to each principal component highlighted in their loadings plot, were linked to the frequencies assigned to vibrations of the CH(2) and CH(3) groups, as well as to vibrations of the SiCH groups. 2D correlation spectroscopy discerned all the sequences of group motion of dendrimer, indicating that during the heating process a reorganization of core structure takes place, followed by a conformational rearrangement of the terminal units.
authors.affiliation: Petru Poni Institute of Macromolecular Chemistry of Romanian Academy, Iasi, Romania. cpopescu@icmpp.ro
authors.forename: Maria-Cristina
authors.initials: MC
authors.lastname: Popescu
authors.forename: Bogdan C
authors.initials: BC
authors.lastname: Simionescu
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry*; D050091:Dendrimers / Q000737:chemistry*; D015999:Multivariate Analysis; D044367:Phase Transition; D025341:Principal Component Analysis; D012821:Silanes / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
chemical_list: D000498:Allyl Compounds; D050091:Dendrimers; D012821:Silanes; C504072:carbosilane