+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

A kinetics and mechanistic study on the role of the structural rigidity of the linker on the substitution reactions of chelated dinuclear Pt(II) complexes

, : A kinetics and mechanistic study on the role of the structural rigidity of the linker on the substitution reactions of chelated dinuclear Pt(II) complexes. Dalton Transactions 41(3): 908-920

Substitution reactions of platinum complexes bearing cyclohexylamine/diamine moieties viz., [Pt(H(2)O)(N,N-bis(2-pyridylmethyl)cyclohexylamine)](CF(3)SO(3))(2), bpcHna; [{Pt(H(2)O)}(2)(N,N,N',N'-tetrakis(2-pyridylmethyl)-trans-1,4-cyclohexyldiamine)](CF(3)SO(3))(4), cHn and [{Pt(H(2)O)}(2)(N,N,N',N'-tetrakis(2-pyridylmethyl)-4,4'-dicyclohexylmethanediamine)](CF(3)SO(3))(4), dcHnm and phenylamine/diamine moieties viz., ([Pt(H(2)O)N,N-bis(2-pyridylmethyl)phenylamine)](CF(3)SO(3))(2), bpPha; [{Pt(H(2)O)}(2)(N,N,N',N'-tetrakis(2-pyridylmethyl)-1,3-phenyldiamine)](CF(3)SO(3))(4), mPh; [{Pt(H(2)O)}(2)(N,N,N',N'-tetrakis(2-pyridylmethyl)-1,4-phenyldiamine)](CF(3)SO(3))(4), pPh and [{Pt(H(2)O)}(2)(N,N,N',N'-tetrakis(2-pyridylmethyl)-4,4'-diphenylmethanediamine)](CF(3)SO(3))(4)), dPhm with thiourea nucleophiles were studied in acidified 0.01 M LiCF(3)SO(3) aqueous medium under pseudo-first-order conditions using stopped-flow and UV-visible spectrophotometric techniques. The rate of substitution follows a similar trend in the two sets of complexes and decreases in the order: bpcHna > dcHnm > cHn and bpPha > dPhm ≈ pPh ≈ mPh), respectively. The result of this study has shown that the rigidity and/or the planarity of a diamine bridge linking the two (2-pyridylmethyl)amine-chelated Pt(II) centres, influences the reactivity of the metal centres by protracting similar symmetry elements within the complexes, which determines the amount of steric influences felt on the coordination square-plane. Hence, the order of reactivity is controlled by both the steric hindrance and the magnitude of the trans σ-inductive effect originating from the linker towards the metal centre. These two factors also impact on the acidity of the complexes. The high negative entropies and low positive enthalpies support an associative mode of activation.


PMID: 22095243

DOI: 10.1039/c1dt11516b

Other references

Zin'kovskiĭ, M.F.; Ignatov, P.I., 1984: Rare case of congenital subaortic stenosis caused by hyperplasia of the anterior cusp of the mitral valve. Grudnaia Khirurgiia: 83-83

Simic, C.; Gladilin, N.; Petrovic, Z.; Lepes, T., 1953: Intestinal parasites in man in Yugoslavia. III. Intestinal parasites in school children in Metohia. Glasnik: 109-120

Lefcheck, J.S.; Brandl, S.J.; Reynolds, P.L.; Smyth, A.R.; Meyer, S.T., 2016: Extending Rapid Ecosystem Function Assessments to Marine Ecosystems: A Reply to Meyer. Trends in Ecology & Evolution 31(4): 251-253

Arima T.; Miyamoto Sudo C.; Hirohata M.; Tanigawa T.; Tsuboi S.; Tsunajima T.; Kuwauchi S.; Imai M., 1975: Further studies on an 11th case of heavy h gamma 1 chain disease clinical study. Acta Medica Okayama 29(3): 199-208

Borgström, B., 1975: On the interactions between pancreatic lipase and colipase and the substrate, and the importance of bile salts. The interactions between pancreatic lipase and colipase and the substrate and the effect of bile salts on these interactions have been investigated by the use of kinetic experiments and studies on the semiquantitative phase distribution of lipase...

Fries, Nils, 1994: Sexual incompatibility in Suillus variegatus. Homokaryons developed from basidiospores produced by sporocarps of Suillus variegatus collected in forests near Uppsala, Sweden, were crossed on agar plates to test mating type. These tests showed that homokaryons from the same spore-stock of S. v...

Butcher, C., 1994: Extension and pastoral development: past, present and future. This paper clarifies past contradictions in extension approaches with nomadic pastoralists in sub-Saharan Africa, reviews current ideas, and outlines future directions evolving from current thought. Extension design, rather than extension content,...

Ubels, J.L.; Rismondo, V.; Edelhauser, H.F., 1987: Treatment of corneal xerophthalmia in rabbits with micromolar doses of topical retinoic acid. Several reports have appeared on the efficacy of topically applied 0.01% or 0.1% all-trans retinoic acid (0.04-0.4 millimolar) for treatment of xerophthalmia, conjunctival squamous metaplasia, and corneal epithelial erosions in humans and animals....

Nasi, S., 2008: From databases to modelling of functional pathways. This short review comments on current informatics resources and methodologies in the study of functional pathways in cell biology. It highlights recent achievements in unveiling the structural design of protein and gene networks and discusses curr...

Cervera, F.; Sanchis, L.; Sánchez-Pérez, J.V.; Martínez-Sala, R.; Rubio, C.; Meseguer, F.; López, C.; Caballero, D.; Sánchez-Dehesa, J., 2002: Refractive acoustic devices for airborne sound. We show that a sonic crystal made of periodic distributions of rigid cylinders in air acts as a new material which allows the construction of refractive acoustic devices for airborne sound. It is demonstrated that, in the long-wave regime, the cry...