PNC Financial Services has annnounced that it is acquiring National City Bank for about $5.6 billion.Cleveland-based National City has been in talks with potential buyers in recent weeks. It was hit hard by the downturn in the mortgage market and announced this week it would lay off about 4,000 workers across the country.Indiana University Southeast business professor Dr. Uric Dufrene says despite its troubles, National City is still a strong brand and a good buy for Pittsburgh-based PNC, which has weathered the financial crisis well."I think PNC is on much stronger ground, stronger footing than some of the other players, like Wachovia and so forth," Dufrene said.National City is Kentucky's largest bank in terms of deposits and has about 1,300 employees in the Louisville region.