Oxyhemocyanin is diamagnetic because of antiferromagnetic coupling of unpaired electron on two similar Cu(II) centers. The diagram that correctly represents this spin-spin coupling is
In oxyhemocyanin each Cu(II) (d9) carries one unpaired electron in a magnetic orbital, and the two copper ions are bridged by a μ-η2:η2 peroxide. Strong superexchange through the peroxide couples the two S = ½ centres antiferromagnetically, so the molecule is EPR-silent and diamagnetic.
Because the two copper centres are similar, their S = ½ levels must start at the same energy. The interaction of the two magnetic orbitals through the bridge produces a lower in-phase and a higher out-of-phase combination; as in any orbital interaction with overlap, the upper level is pushed up by more than the lower level is pulled down. The two electrons pair in the lower combination, giving the diamagnetic singlet ground state with the paramagnetic state far above it.
Diagrams in which the A and B levels sit at different energies describe two dissimilar centres and contradict the stem. The diagram in which the lower level drops much more than the upper rises does not show the overlap-driven, strongly destabilised upper combination that characterises this coupling.
the symmetric diagram in which the upper combination rises well above the two S = ½ levels while the lower lies just below them option is correct.
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.................... is a client server application that identifies each host on the internet with a unique user-friendly name.
Every OS has a ................ or .......... which primarily resides in the main memory of the computer to perform some of the basic functions of the OS.
(i) Kernel
(ii) Interface
(iii) Nucleus
(iv) Compiler
Codes:
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(i) Machine language
(ii) Assembly language
(iii) High level language
(iv) Natural language
Codes:
Match the following:
List I List II (a) New York Public Library (i) Shelv AR (b) Miami University Augmented Research Group (ii) Smart library (c) Oula University Library (iii) Wolf Walk (d) North Carolina State University (iv) Find the future Codes:
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