Crystal structure and experimental and theoretical studies of the second-order nonlinear optical properties of salts of triphenylguanidine with carboxylic acids.
N,N',N''-triphenylguanidinium carboxylate salts have been prepared by acid-base reactions of triphenylguanidine with formic, benzoic, and m-methoxybenzoic acids, and their single-crystal X-ray structure analysis has been performed. The salts were found to crystallize into noncentrosymmetric structures with an orthorhombic space group P2(1)2(1)2(1) for the formate and m-methoxybenzoate salts and a monoclinic space group Cc for the benzoate salt. The anions and cations are linked by intermolecular hydrogen bonds with the same motifs in the three salts. By using the molecular structures, the molecular first hyperpolarizabilities of several clusters were determined by semiempirical methods, and the components of the second-order susceptibility tensor, d, of triphenylguanidine and those of the reported crystals were evaluated using the oriented gas model with two different local-field corrections. The efficiency of the second-harmonic generation of triphenylguanidine and that of the reported triphenylguanidinium salts were measured using the Kurtz and Perry powder method.
Silva
Pedro S Pereira
PS
CEMDRX, Physics Department, University of Coimbra, P-3004-516 Coimbra, Portugal. psidonio@pollux.fis.uc.pt
Cardoso
Cláudia
C
Silva
Manuela Ramos
MR
Paixão
José A
JA
Beja
Ana Matos
AM
Garcia
Maria Helena
MH
Lopes
Nelson
N
D002264:Carboxylic Acids / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D006146:Guanidines / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D012492:Salts / Q000138:chemical synthesis / Q000737:chemistry
D002264:Carboxylic Acids; D006146:Guanidines; C549456:N,N',N''-triphenylguanidinium carboxylate; D012492:Salts; C026943:phenylguanidine